Epidemiology and genetics of CTX-M extended-spectrum β-lactamases in Gram-negative bacteria

Figures & data

Table 1.  CTX-M ESBLs and their bacterial hosts.

CTX-M (alternate name)	Bacterial host	GenBank accession no.	Reference
CTX-M-1 (MEN-1)	Escherichia coli	X92506	Bauernfeind et al., 1996
	Enterobacter cloacae		al Naiemi et al., 2006
	Klebsiella pneumoniae		Komatsu et al., 2001
	Proteus mirabilis		al Naiemi et al., 2006
	Pseudomonas aeruginosa		al Naiemi et al., 2006
	Salmonella enterica		Rodríguez et al., 2009
	Serratia marcescens		Choi et al., 2007
	Stenotrophomonas maltophilia		al Naiemi et al., 2006
CTX-M-2	Salmonella enterica	X92507	Bauernfeind et al., 1996
	Acinetobacter baumannii		Nagano et al., 2004
	Citrobacter koseri		al Naiemi et al., 2006
	Escherichia coli		Arduino et al., 2003
	Enterobacter cloacae		Arduino et al., 2003
	Klebsiella pneumoniae		Arduino et al., 2003
	Morganella morganii		Power et al., 2005
	Proteus mirabilis		Bonnet et al., 2000
	Providencia stuartii		Minarini et al. 2009
	Pseudomonas aeruginosa		Arduino et al., 2003
	Serratia marcescens		Arduino et al., 2003
	Vibrio cholerae		Soler Bistué et al., 2006
CTX-M-3	Citrobacter freundii	Y10278	Gniadkowski et al., 1998
	Aeromonas caviae		Ye et al., 2010
	Escherichia coli		Yan et al., 2000
	Enterobacter cloacae		De Champs et al., 2000
	Enterobacter aerogenes		Liu et al., 2009
	Klebsiella pneumoniae		Baraniak et al., 2002b
	Klebsiella oxytoca		Baraniak et al., 2002b
	Morganella morganii		Baraniak et al., 2002b
	Proteus mirabilis		Eckert et al., 2006
	Salmonella enterica		Gierczyński et al., 2003
	Sarratia marcescens		Baraniak et al., 2002b
	Shigella flexneri		Galimand et al., 2005
	Shigella sonnei		Acikgoz et al., 2003
CTX-M-4	Salmonella enterica	Y14156	Gazouli et al., 1998b
CTX-M-5	Salmonella enterica	U95364	Bradford et al., 1998
	Acinetobacter baumannii	AF462635
CTX-M-6 (renumbered)	Salmonella enterica	AJ005044	Gazouli et al., 1998a
CTX-M-7 (renumbered)	Salmonella enterica	AJ005045	Gazouli et al., 1998a
CTX-M-8	Citrobacter amalonaticus	AF189721	Bonnet et al., 2000
	Enterobacter cloacae		Bonnet et al., 2000
	Enterobacter aerogenes		Bonnet et al., 2000
	Escherichia coli		Minarini et al. 2009
CTX-M-9	Escherichia coli	AF174129	Sabaté et al., 2000
	Citrobacter freundii		Minarini et al. 2009
	Enterobacter aerogenes	EF441350
	Enterobacter cloacae		Chanawong et al., 2002
	Enterobacter hormaechei		Ho et al., 2005b
	Klebsiella pneumoniae		Chanawong et al., 2002
	Klebsiella oxytoca		Alobwede et al., 2003
	Salmonella enterica		García Fernández et al., 2007
	Serratia marcescens		Choi et al., 2007
CTX-M-10	Escherichia coli	AF255298	Oliver et al., 2001
	Citrobacter freundii		Valverde et al., 2004
	Enterobacter cloacae		Cantón et al., 2002
	Enterobacter gergoviae		Cantón et al., 2002
	Klebsiella pneumoniae		Coque et al., 2002
	Salmonella enterica		Cartelle et al., 2006
CTX-M-11	Klebsiella pneumoniae	AY005110
CTX-M-12	Klebsiella pneumoniae	AF305837	Kariuki et al., 2001
	Escherichia coli		Bae et al., 2006b
	Proteus mirabilis		Song et al., 2011
CTX-M-13	Klebsiella pneumoniae	AF252623	Chanawong et al., 2002
	Escherichia coli	DQ058147
	Enterobacter cloacae	AF462399
	Enterobacter hormaechei		Ho et al., 2005b
	Proteus mirabilis		Ho et al., 2005a
CTX-M-14	Escherichia coli	AF252622	Chanawong et al., 2002
	Citrobacter freundii		Kanamori et al., 2011
	Citrobacter koseri		Kanamori et al., 2011
	Enterobacter cloacae		Chanawong et al., 2002
	Enterobacter hormaechei		Ho et al. 2005b
	Klebsiella pneumoniae		Chanawong et al., 2002
	Proteus mirabilis		Ho et al., 2005a
	Providencia stuartii		Liu et al., 2009
	Salmonella enterica		Romero et al., 2004
	Serratia liquefaciens	AF462398
	Shigella flexneri	DQ350883
	Shigella sonnei		Pai et al., 2001
CTX-M-15 (UOE-1) *	Escherichia coli	AY044436	Karim et al., 2001
	Acinetobacter baumannii		Shakil & Khan, 2010
	Aeromonas hydrophila		Gómez-Garcés et al., 2011
	Citrobacter freundii	HQ214043
	Citrobacter koseri		Kanamori et al., 2011
	Enterobacter aerogenes		Kim et al., 2005
	Enterobacter cloacae		Moubareck et al., 2005
	Enterobacter gergoviae	EU118595
	Klebsiella pneumoniae		Lartigue et al., 2003
	Klebsiella oxytoca		Zhang et al., 2008
	Morganella morganii		al Naiemi et al., 2006
	Pantoea agglomerans		Aibinu et al., 2012
	Proteus mirabilis		Song et al., 2011
	Salmonella enterica		Weill et al., 2004
	Serratia marcescens		Baraniak et al., 2002a
	Shigella flexneri		Zhang et al., 2011
	Shigella sonnei		Hrabák et al., 2008
CTX-M-16 *	Escherichia coli	AY029068	Bonnet et al., 2001
CTX-M-17	Klebsiella pneumoniae	AY033516	Cao et al., 2002
CTX-M-18^§	Klebsiella pneumoniae	AF325133	Poirel et al., 2001
CTX-M-19 *	Klebsiella pneumoniae	AF325134	Poirel et al., 2001
CTX-M-20	Proteus mirabilis	AJ416344	Saladin et al., 2002
CTX-M-21	Escherichia coli	AJ416346	Saladin et al., 2002
CTX-M-22	Klebsiella pneumoniae	AY080894	Yu et al., 2007
	Escherichia coli		Yu et al., 2007
	Enterobacter cloacae		Liu et al., 2007
	Serratia liquefaciens	HM470254
	Serratia marcescens	DQ309026
CTX-M-23 *	Escherichia coli	AF488377	Stürenburg et al., 2004
	Klebsiella pneumoniae		Stürenburg et al., 2004
CTX-M-24	Klebsiella pneumoniae	AY143430	Yu et al., 2007
	Escherichia coli		Yu et al., 2007
	Enterobacter aerogenes		Ho et al., 2005b
	Proteus mirabilis		Wu et al., 2008
	Shigella sonnei	FN594520
CTX-M-25 *	Escherichia coli	AF518567	Munday et al., 2004
	Klebsiella pneumoniae		Navon-Venezia et al., 2008
	Proteus mirabilis		Navon-Venezia et al., 2008
CTX-M-26	Klebsiella pneumoniae	AY157676	Brenwald et al., 2003
CTX-M-27 *	Escherichia coli	AY156923	Bonnet et al., 2003
	Salmonella enterica		Bouallègue-Godet et al., 2005
	Shigella sonnei	HM595763
CTX-M-28	Escherichia coli	AJ549244	Galimand et al., 2005
	Enterobacter sp.	EU531513
	Klebsiella pneumoniae		Yu et al., 2007
	Salmonella enterica		Hasman et al., 2005
CTX-M-29	Escherichia coli	AY267213	Yu et al., 2007
CTX-M-30	Citrobacter freundii	AY292654	Abdalhamid et al., 2004
CTX-M-31	Providencia stuartii	AJ567481	Quinteros et al., 2003
	Escherichia coli		Quinteros et al., 2003
CTX-M-32 *	Escherichia coli	AJ557142	Cartelle et al., 2004
	Klebsiella pneumoniae		Mendonça et al., 2009
	Proteus mirabilis		Fernández et al., 2007
CTX-M-33	Escherichia coli	AY238472	Galani et al., 2007
CTX-M-34	Escherichia coli	AY515297	Miró et al., 2005
CTX-M-35 *	Klebsiella pneumoniae	AB176532
	Citrobacter koseri		Tian et al., 2010
	Escherichia coli	AB176533
	Klebsiella oxytoca	AB176534
CTX-M-36	Escherichia coli	AB177384
CTX-M-37 *	Enterobacter cloacae	AY649755
	Salmonella enterica		Govinden et al., 2006
CTX-M-38	Klebsiella pneumoniae	AY822595
CTX-M-39	Escherichia coli	AY954516	Chmelnitsky et al., 2005
	Enterobacter cloacae		Navon-Venezia et al., 2008
	Klebsiella pneumoniae		Navon-Venezia et al., 2008
CTX-M-40 *	Escherichia coli	AY750914	Hopkins et al., 2006
CTX-M-41	Proteus mirabilis	DQ023162	Navon-Venezia et al., 2008
CTX-M-42 *	Escherichia coli	DQ061159	Stepanova et al., 2008
CTX-M-43	Acinetobacter baumannii	DQ102702	Celenza et al., 2006
	Enterobacter aerogenes		Celenza et al., 2006
	Enterobacter cloacae		Celenza et al., 2006
	Morganella morganii		Celenza et al., 2006
	Pseudomonas aeruginosa		Celenza et al., 2006
CTX-M-44 (Toho-1)	Escherichia coli	D37830	Ishii et al., 1995
CTX-M-45 (Toho-2)	Escherichia coli	D89862	Ma et al., 1998
CTX-M-46	Klebsiella pneumoniae	AY847147	Cheng et al., 2008
CTX-M-47	Escherichia coli	AY847143	Cheng et al., 2008
	Klebsiella pneumoniae		Cheng et al., 2008
CTX-M-48	Klebsiella pneumoniae	AY847144	Cheng et al., 2008
	Escherichia coli		Cheng et al., 2008
CTX-M-49	Klebsiella pneumoniae	AY847145	Cheng et al., 2008
CTX-M-50	Klebsiella pneumoniae	AY847146	Cheng et al., 2008
CTX-M-51	Escherichia coli	DQ211987
CTX-M-52	Klebsiella pneumoniae	DQ223685
CTX-M-53 *	Salmonella enterica	DQ268764	Doublet et al., 2009
CTX-M-54 *	Klebsiella pneumoniae	DQ303459	Bae et al., 2006a
CTX-M-55 *	Escherichia coli	DQ885477	Kiratisin et al., 2007
	Klebsiella pneumoniae		Kiratisin et al., 2007
	Shigella sonnei		Zhang et al., 2011
CTX-M-56	Escherichia coli	EF374097	Pallecchi et al., 2007
CTX-M-57^§	Salmonella enterica	DQ810789	Hopkins et al., 2008
	Shigella sonnei	EU086736
CTX-M-58 *	Escherichia coli	EF210159
CTX-M-59	Klebsiella pneumoniae	DQ408762	de Oliveira et al., 2008
CTX-M-60	Klebsiella pneumoniae	AM411407
CTX-M-61	Salmonella enterica	EF219142	Brasme et al., 2007
	Klebsiella pneumoniae		Mendonça et al., 2009
CTX-M-62 *	Klebsiella pneumoniae	EF219134	Zong et al., 2008
CTX-M-63	Klebsiella pneumoniae	AB205197
	Morganella morganii	EU660216
	Salmonella enterica		Pornruangwong et al., 2011
CTX-M-64 *	Shigella sonnei	AB284167	Nagano et al., 2009
	Escherichia coli		Sun et al., 2010
	Enterobacter cloacae	GQ300937
CTX-M-65	Escherichia coli	EF418608	Doi et al. 2008
	Citrobacter freundii	EF394372
	Salmonella enterica	FJ907380
CTX-M-66	Proteus mirabilis	EF576988	Wu et al., 2008
CTX-M-67	Escherichia coli	EF581888	Oteo et al., 2008
CTX-M-68	Klebsiella pneumoniae	EU177100	Heffernan et al., 2009
CTX-M-69	Escherichia coli	EU402393
CTX-M-70^†		Assigned
CTX-M-71	Klebsiella pneumoniae	FJ815436	Schneider et al., 2009
CTX-M-72	Klebsiella pneumoniae	AY847148	Cheng et al., 2009
CTX-M-73^†		Assigned
CTX-M-74	Enterobacter cloacae	GQ149243	Minarini et al., 2009
CTX-M-75	Providencia stuartii	GQ149244	Minarini et al., 2009
c-CTX-M-76^‡	Kluyvera ascorbata	AM982520
c-CTX-M-77^‡	Kluyvera ascorbata	AM982521
c-CTX-M-78^‡	Kluyvera georgiana	AM982522	Rodríguez et al., 2010
CTX-M-79	Escherichia coli	EF426798	Tian et al., 2008
CTX-M-80	Klebsiella pneumoniae	EU202673	Cheng et al., 2010
CTX-M-81	Klebsiella pneumoniae	EU136031	Cheng et al., 2010
CTX-M-82 *	Escherichia coli	DQ256091	Liu et al., 2009
CTX-M-83	Salmonella enterica	FJ214366	Cui et al., 2009
CTX-M-84	Salmonella enterica	FJ214367	Cui et al., 2009
CTX-M-85	Salmonella enterica	FJ214368	Cui et al., 2009
CTX-M-86	Salmonella enterica	FJ214369	Cui et al., 2009
CTX-M-87 (renumbered)	Escherichia coli	EU545409	Yin et al., 2009
CTX-M-88	Salmonella enterica	FJ873739	Ranjbar et al., 2010
CTX-M-89	Proteus mirabilis	FJ971899	McGettigan et al., 2009
	Enterobacter cloacae	FJ966096
CTX-M-90	Salmonella enterica	FJ907381
	Proteus mirabilis		Song et al., 2011
CTX-M-91	Proteus mirabilis	GQ870432
CTX-M-92	Escherichia coli	GU127598	Seputiene et al., 2010
	Klebsiella pneumoniae		Seputiene et al., 2010
CTX-M-93 *	Escherichia coli	HQ166709	Djamdjian et al., 2011
CTX-M-94	Escherichia coli	HM167760
c-CTX-M-95^‡	Kluyvera ascorbata	FN813245
CTX-M-96 (CTX-M-12a)	Klebsiella pneumoniae	AJ704396
CTX-M-97	Escherichia coli	HM776707
CTX-M-98	Escherichia coli	HM755448
CTX-M-99	Klebsiella pneumoniae	HM803271
CTX-M-100^†		Assigned
CTX-M-101	Escherichia coli	HQ398214
CTX-M-102	Escherichia coli	HQ398215
CTX-M-103^†		Assigned
CTX-M-104	Escherichia coli	HQ833652
CTX-M-105	Escherichia coli	HQ833651
CTX-M-106	Escherichia coli	HQ913565
CTX-M-107	Shigella flexneri	JF274244	Zhang et al., 2011
CTX-M-108	Shigella flexneri	JF274245	Zhang et al., 2011
CTX-M-109	Shigella flexneri	JF274248	Zhang et al., 2011
CTX-M-110	Shigella sonnei	JF274242	Zhang et al., 2011
CTX-M-111	Shigella flexneri	JF274243	Zhang et al., 2011
CTX-M-112	Shigella sonnei	JF274246	Zhang et al., 2011
CTX-M-113	Shigella flexneri	JF274247	Zhang et al., 2011
CTX-M-114	Providencia rettgeri	GQ351346
CTX-M-115^†		Assigned
CTX-M-116	Proteus mirabilis	JF966749
CTX-M-117	Escherichia coli	JN227085
CTX-M-118		Withdrawn
CTX-M-119^†		Assigned
CTX-M-120^†		Assigned
CTX-M-121	Escherichia coli	JN790862
CTX-M-122	Escherichia coli	JN790863
CTX-M-123	Escherichia coli	JN790864
CTX-M-124^†		Assigned

*, with enhanced catalytic efficiencies against ceftazidime; †, have been assigned in the Lahey database (Jacoby and Bush 2012); ‡, chromosome-encoded intrinsic cefotaximase identified in Kluyvera spp.; §, CTX-M-18 and CTX-M-14, CTX-M-57 and CTX-M-55 are identical in their amino acid sequences.

Figure 1.  Phylogenetic tree of CTX-M family based on amino-acid sequences. DNASIS Pro v2.10 (Hitachi Software Engineering Co., Tokyo, Japan) was used to align the amino-acid sequences and construct the phylogenetic tree. The amino-acid sequences were downloaded from GenBank under the accession numbers cited in Table 1. The branch lengths are drawn to scale and are proportional to the number of different amino-acid residues. The scale bars of 0.05 and 0.005 represent 5% and 0.5% amino-acid difference, respectively.

Table 2.  Amino acid substitutions of CTX-M variants compared to their representative enzymes.

CTX-M	Amino acid substitution	CTX-M	Amino acid substitution
Cluster 2	vs. CTX-M-2	Cluster 8	vs. CTX-M-8
CTX-M-4	L48Q, R61V, K98R, K99A, A125G, T171S, L225M, V230G	CTX-M-40	K89N, T109A, N158D, N192H
CTX-M-5	A26T, V230G, E253A, I278V	CTX-M-63	K89N, T109A, N158D, N192H, S274N
CTX-M-6	R61L, K99A, A125G, T171S, S228C, I278V	Cluster 14	vs. CTX-M-14
CTX-M-7	R61V, K98R, K99A, E121Q, A125G, T171S, V230G, I278V	CTX-M-9	V231A
CTX-M-20	I278F	CTX-M-13	V2M, A52K, A154E
CTX-M-31	T159S	CTX-M-16	V231A, D240G
CTX-M-35	P167S	CTX-M-17	E288K
CTX-M-43	D240G, S274R	CTX-M-19	P167S
CTX-M-44	S274R	CTX-M-21	A9G, A10G, C12G, L22F, V29G
CTX-M-56	S274N	CTX-M-24	S274R
CTX-M-59	H89L	CTX-M-27	D240G
CTX-M-74	P167T	CTX-M-38	S220R
Cluster 2	vs. CTX-M-2	Cluster 14	vs. CTX-M-14
CTX-M-75	P14S	CTX-M-46	S27N, A47P
CTX-M-92	A205T	CTX-M-47	G42R
CTX-M-97	R3G	CTX-M-48	S27N
Cluster 3	vs. CTX-M-3	CTX-M-49	G42R, A47P
CTX-M-1	A77V, N114D, A140S, D288N	CTX-M-50	A47P
CTX-M-10	A27V, R38Q	CTX-M-51	A77V, V231A
CTX-M-11	E35G, L119P, D277H, deletion of ^282AAKIVTDGL^290	CTX-M-65	A77V, S274R
CTX-M-12	T12A, N89S, V278I	CTX-M-67	N106S
CTX-M-15	D240G	CTX-M-81	K82E, K98Q, N132H
CTX-M-22	D288N	CTX-M-83	Q56H
CTX-M-23	A77V, P167T, D288N	CTX-M-84	T209A
CTX-M-28	D240G, D288N	CTX-M-85	L119P
CTX-M-29	T12A, N114D, D240G, D288N	CTX-M-86	I108F
CTX-M-30	T12A, N114D	CTX-M-87	A77V, P167L
CTX-M-32	A77V, N114D, A140S, D240G, D288N	CTX-M-90	A77V
CTX-M-33	N106S, D240G	CTX-M-93	L169Q, D240G
CTX-M-34	A27V, R38Q, G238C	CTX-M-98	A77V, D240G
CTX-M-36	N114D, A140S, D288N	CTX-M-99	P167S, S274R
CTX-M-37	Y23H, R38Q, N114D	CTX-M-102	A205E, D240G
CTX-M-42	P167T	CTX-M-104	S274N
CTX-M-52	A77V, P167S	CTX-M-105	A77V, A205E, D240G
CTX-M-53	A27V, R38Q, A77V, D240G, T263I	CTX-M-106	K234R, R276H, deletion of ^290L
CTX-M-54	P167Q	CTX-M-110	K111E, insertion of N before ^290L
CTX-M-55	A77V, D240G	CTX-M-111	P145Q
CTX-M-58	A77V, N114D, A140S, P167T, D288N	CTX-M-112	S123G
CTX-M-60	T12A, N89S, V278I, A77V	CTX-M-113	Q83R
CTX-M-61	A77V, N114D, A140S	CTX-M-121	A109T, D240G
CTX-M-62	P167S	CTX-M-122	A154S, S274R
CTX-M-66	S19N	Cluster 25	vs. CTX-M-25
CTX-M-68	Y23H, A27V, E158D	CTX-M-26	V77A, Q222R, G240D
CTX-M-69	A77V, D240G, K271N, D288N	CTX-M-39	V77A, G240D
CTX-M-71	G238C, D240G	CTX-M-41	V77A, I103V, S123I
CTX-M-72	R164G	CTX-M-89	G240D
CTX-M-79	A77V, D240G, D288N	CTX-M-91	A189S, G240D
CTX-M-80	A27V	CTX-M-94	V77A, F119L
CTX-M-82	A67P, D240G	Cluster 64	vs. CTX-M-64
CTX-M-88CTX-M-96	D240G, R276HT12A, N89S, D240G, V278I	CTX-M-123	P67A, Q83K, T86S, Q87E, K88P, Q89N, P94R, P99K, A100S, T118S, A227T, V230T
CTX-M-101	S123I, D240G		T118S, A227T, V230T
CTX-M-107	K234R, D240G, deletion of ^288DGL^290
CTX-M-108	V95A, D240G, deletion of ^288DGL^290
CTX-M-109	Q56R, D240G, D288K, deletion of ^289GL^290
CTX-M-114	V74A, A77V, D240G
CTX-M-116	A77V, D288N
CTX-M-117	P174Q, D240G

Figure 2.  Comparison of amino-acid sequences of seven representative enzymes in the CTX-M family. Amino-acids are numbered according to the standard numbering scheme for the class A serine β-lactamases, giving the active site serine residue the Ambler number 70. Dots indicate identical amino-acids compared to CTX-M-2. Deletion mutations are expressed with short lines. The underlined amino-acids, ⁷⁰SXXK⁷³, ¹⁰⁷P, 130SDN¹³², ¹⁴³GG¹⁴⁴, ¹⁶⁶E and ²³⁴KXG²³⁶, represent the conserved residues in typical class A serine β-lactamases.

Figure 3.  Identification of intrinsic cefotaximase genes in Kluyvera spp. as the original sources of acquired CTX-Ms based on their amino-acid identities and the homologies of neighboring sequences of the associated genes. c-CTX-M, CTX-M identified on chromosome of Kluyvera spp.; p-KLUC-2, KLUC-2 identified on plasmid in a clinical isolate of Enterobacter cloacae.

Table 3.  Genetic platforms of CTX-M enzymes.

CTX-M	Genetic platform	Bacterial host	Reference/GenBank accession no.
CTX-M-1	ISEcp1–blaCTX-M-1–orf477	E. coli	Eckert et al., 2006
	ISEcp1Δ----IS26–ISEcp1Δ–blaCTX-M-1	K. pneumoniae	Diestra et al., 2009
	IS26–ISEcp1Δ–blaCTX-M-1– orf477Δ	E. coli	Cullik et al., 2010
	intI1–dfrA17–aadA5–qacEΔ1–sul1–ISCR1–blaCTX-M-1–orf3–IS3000–qacEΔ1–sul1-like–orf5	E. coli	Su et al., 2008
CTX-M-2	intI1–aacA4–blaOXA-2–orfD–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1	P. mirabilis	Arduino et al., 2002
	intI1–aacA4–blaOXA-2–orfD–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1–orf5	V. cholera	Soler Bistué et al., 2006
	intI1–aacA4–blaOXA-2–orfD–qacEΔ1–sul1–ISCR1–dfrA10–blaCTX-M-2–orf3Δ–qacEΔ1–sul1–orf5–tniBΔ–IS1326	S. enterica	AJ311891
	intI1–dfrA12–orfF–aadA2–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1–orf5–IS1326	K. pneumoniae	EU780013
	intI1–estX–aadA1–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1–orf5–IS1326	E. coli	Valverde et al., 2006
	intI1–aac(6′)-Iq–aadA1–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1	K. pneumoniae	EU622037
	intI1–aadA1–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1	K. pneumoniae	EU622040
	intI1–aadA2–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1	K. pneumoniae	EU622038
	intI1–dhfrh1–aadA2–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1	E. coli	Eckert et al., 2006
	intI1–dfrA1–aadA1–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1	S. enterica	EF592570
	intI1–dfrA12–orfF–aadA2–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1	S. enterica	EF592571
	intI1–dfrA21–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1	K. pneumoniae	EU622039
	intI1–dfr22–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1	K. pneumoniae	EU622041
	intI1–orf1–cat–orf2–aadA1–qacEΔ1–sul1–ISCR1–blaCTX-M-2–orf3Δ–qacEΔ1–sul1	P. mirabilis	Song et al., 2011
	ISEcp1–blaCTX-M-2	P. mirabilis	Harada et al., 2012
CTX-M-3	ISEcp1–blaCTX-M-3–orf477	K. pneumoniae	Eckert et al., 2006
	ISEcp1–blaCTX-M-3–orf477–mucA	K. pneumoniae	Eckert et al., 2006
	ISEcp1-like–blaCTX-M-3–orf477-like	P. mirabilis	Wu et al., 2008
	ISEcp1–blaCTX-M-3	E. coli	Diestra et al., 2009
	ISEcp1–IS1–blaCTX-M-3–orf477–mucA	K. pneumoniae	Eckert et al., 2006
	ISEcp1–blaCTX-M-3–orf–mucA	C. freundii	Lartigue et al., 2004
	IS26–ISEcp1Δ–blaCTX-M-3	E. coli	Diestra et al., 2009
	IS26–ISEcp1–blaCTX-M-3–orf477–mucA	P. mirabilis	Eckert et al., 2006
CTX-M-9	intI1–aadB–qacEΔ1–sul1–ISCR1–blaCTX-M-9–orf3-like–IS3000	E. cloacae	DQ108615
	intI1–dhfr12–orfX–aadA8–qacEΔ1–sul1–ISCR1–blaCTX-M-9–orf3–orf339Δ	E. coli	Eckert et al., 2006
	intI1–dfrA16–aadA2–qacEΔ1–sul1–ISCR1–blaCTX-M-9–orf3-like–IS3000–qacEΔ1–sul1	E. coli	Sabaté et al., 2002
	ISCR1–blaCTX-M-9	E. coli	Diestra et al., 2009
	ISEcp1–blaCTX-M-9	C. freundii	Minarini et al. 2009
CTX-M-10	Tn1000-like–orf2–orf3–orf4–DNA-invertase-gene–blaCTX-M-10–orf7–orf8–IS4321–orf10–orf11–IS5	K. pneumoniae	Oliver et al., 2005
	ISEcp1–blaCTX-M-10–orf–Tn5396	E. coli	Lartigue et al., 2004
CTX-M-12	ISEcp1–blaCTX-M-12	P. mirabilis	Song et al., 2011
CTX-M-13	ISEcp1B–blaCTX-M-13	E. coli	DQ058147
CTX-M-14	ISEcp1–blaCTX-M-14–IS903	E. coli	Lartigue et al., 2004
	ISEcp1-like–blaCTX-M-14–IS903-like	P. mirabilis	Wu et al., 2008
	ISEcp1–IS10–blaCTX-M-14–IS903	E. coli	Eckert et al., 2006
	ISEcp1–IS10–blaCTX-M-14–IS903D	E. coli	EU136400
	IS26–ISEcp1–blaCTX-M-14	K. pneumoniae	Eckert et al., 2006
	IS26–ISEcp1–blaCTX-M-14–IS903	K. pneumoniae	GQ385317
	IS26–blaCTX-M-14–IS903D	S. enterica	Izumiya et al., 2005
	ISEcp1B–blaCTX-M-14	E. coli	Billard-Pomares et al., 2011
	intI1–dfrA12–orfF–aadA2–qacEΔ1–sul1–ISCR1–blaCTX-M-14–IS903-like	E. coli	Bae et al., 2007
	intI1–dfrA12–orfF–aadA2–qacEΔ1–sul1–orf5–IS6100–ISCR1–ISEcp1Δ–blaCTX-M-14–IS903D	E. coli	Bae et al., 2008
CTX-M-15	ISEcp1–blaCTX-M-15	A. hydrophila	Gómez-Garcés et al., 2011
	ISEcp1–blaCTX-M-15–orf477	E. coli	Eckert et al., 2006
	ISEcp1–blaCTX-M-15–orf477Δ–Tn3	A. baumannii	JN788267
	Tn3Δ–ISEcp1–blaCTX-M-15–orf–Tn3Δ	E. coli	Lartigue et al., 2004
	IS26–ISEcp1–blaCTX-M-15–orf477	E. coli	Eckert et al., 2006
	IS26–ISEcp1–blaCTX-M-15–orf477Δ	S. enterica	Fabre et al., 2009
	blaTEM-1–tnpR–tnpA–ISEcp1–blaCTX-M-15–orf477	E. coli	Eckert et al., 2006
CTX-M-16	ISEcp1–blaCTX-M-16–IS903	E. coli	Brasme et al., 2007
	ISEcp1–blaCTX-M-16–orf3–orf339–orf477	E. coli	AM910790
CTX-M-17	ISEcp1-like–blaCTX-M-17–IS903C	K. pneumoniae	Cao et al., 2002
CTX-M-19	intI1-like–aacA4–cmlA1–qacEΔ1–sul1–Tn1721–ISEcp1B–blaCTX-M-19–IS903D	K. pneumoniae	Poirel et al., 2003
CTX-M-20	ISEcp1–blaCTX-M-20	P. mirabilis	AJ416344
CTX-M-21	ISEcp1–blaCTX-M-21	E. coli	AJ416346
CTX-M-22	ISEcp1Δ–IS26–blaCTX-M-22–orf477–ISEcp1Δ	S. liquefaciens	HM470254
CTX-M-24	ISEcp1–blaCTX-M-24–IS903	E. coli	Eckert et al., 2006
	ISEcp1-like–blaCTX-M-24–IS903-like	P. mirabilis	Wu et al., 2008
CTX-M-25	intI1–aacA4–blaOXA-2–ISEcp1–blaCTX-M-25–qacEΔ1–sul1	P. mirabilis	Navon-Venezia et al. 2008
	ISEcp1Δ–IS50-A–ISEcp1Δ–blaCTX-M-25–orfX	E. coli	Munday et al. 2004
CTX-M-26	intI1–dhfr7–ISEcp1–blaCTX-M-26–qacEΔ1–sul1	K. pneumoniae	Navon-Venezia et al. 2008
	ISEcp1–blaCTX-M-26–orfX	K. pneumoniae	Munday et al. 2004
CTX-M-27	ISEcp1–blaCTX-M-27	S. enterica	Bouallègue-Godet et al., 2005
	ISEcp1–blaCTX-M-27–IS903	E. coli	Sun et al., 2010
CTX-M-32	ISEcp1Δ–IS5–IS1A–ISEcp1Δ–blaCTX-M-32–orf477	E. coli	Fernández et al., 2007
	ISEcp1Δ–IS5–ISEcp1Δ–blaCTX-M-32	E. coli	Diestra et al., 2009
CTX-M-39	intI1–dhfr7–ISEcp1–blaCTX-M-39–qacEΔ1–sul1	E. coli	Navon-Venezia et al. 2008
	intI1–aadA1–ISEcp1–blaCTX-M-39–qacEΔ1–sul1	E. coli	Navon-Venezia et al. 2008
CTX-M-40	ISEcp1-like–blaCTX-M-40	E. coli	Hopkins et al., 2006
CTX-M-42	ISEcp1–blaCTX-M-42	E. coli	DQ061159
CTX-M-53	ISSen2---blaCTX-M-53–orf477Δ–IS26	S. enterica	Doublet et al., 2009
CTX-M-54	ISEcp1–blaCTX-M-54–IS903-like	K. pneumoniae	Bae et al., 2006a
CTX-M-55	ISEcp1–blaCTX-M-55–orf477	E. coli	Sun et al., 2010
	ISEcp1Δ–IS1294–blaCTX-M-55–orf477	E. coli	JN977127
CTX-M-59	intI1–dfr15b–cmlA4-like–aadA2–qacEΔ1–sul1–ISCR1–blaCTX-M-59–orf3Δ–qacEΔ1	K. pneumoniae	EU622856
CTX-M-62	ISEcp1–blaCTX-M-62–ISEcp1Δ1/Δ2	K. pneumoniae	Zong et al., 2010
CTX-M-64	ISEcp1–blaCTX-M-64–orf477	S. sonnei	Nagano et al., 2009
CTX-M-65	ISEcp1–blaCTX-M-65–IS903	E. coli	Sun et al., 2010
CTX-M-66	ISEcp1-like–blaCTX-M-66–orf477-like	P. mirabilis	Wu et al., 2008
CTX-M-74	ISCR1–blaCTX-M-74–orf3Δ–qacEΔ1–sul1	E. cloacae	Minarini et al. 2009
CTX-M-75	ISCR1–blaCTX-M-75–orf3Δ–qacEΔ1–sul1	P. stuartii	Minarini et al. 2009
CTX-M-79	ISEcp1–blaCTX-M-79	E. coli	FJ169498
CTX-M-82	ISEcp1–blaCTX-M-82	E. coli	GU477621
CTX-M-89	ISEcp1-like–blaCTX-M-89–orf477-like	E. cloacae	FJ966096
CTX-M-90	ISEcp1–blaCTX-M-90–IS903-like	P. mirabilis	Song et al., 2011
	ISEcp1–blaCTX-M-90	P. mirabilis	Song et al., 2011
CTX-M-93	ISEcp1–blaCTX-M-93–IS903	E. coli	Djamdjian et al., 2011
CTX-M-98	ISEcp1–blaCTX-M-98–IS903	E. coli	HM755448
CTX-M-101	ISEcp1–blaCTX-M-101	E. coli	HQ398214
CTX-M-102	ISEcp1–blaCTX-M-102–IS903	E. coli	HQ398215
CTX-M-104	ISEcp1–blaCTX-M-104–IS903	E. coli	HQ833652
CTX-M-105	ISEcp1–blaCTX-M-105–IS903	E. coli	HQ833651
CTX-M-116	ISEcp1–blaCTX-M-116	P. mirabilis	JF966749
CTX-M-121	ISEcp1–blaCTX-M-121–IS903	E. coli	JN790862
CTX-M-122	ISEcp1–blaCTX-M-122–IS903	E. coli	JN790863
CTX-M-123	ISEcp1–blaCTX-M-123	E. coli	JN790864

Figure 4.  Typical genetic platforms of CTX-M enzymes. A & B: the bla_CTX-M gene cassettes bracketed upstream by ISEcp1/ISEcp1-like and downstream by IS903/IS903-like (A) or orf477/orf477-like (B); C: bla_CTX-M genes associated with class 1 integron-ISEcp1; D & E: bla_CTX-M genes associated with class 1 integron-ISCR1 complex. CS, conserved segment; intI, integrase gene; qacE▵1, quaternary ammonium resistance gene; sul1, sulphonamide resistance gene; 3′-CS2, the second copy of 3′-conserved segment.

Table 4.  Plasmids associated with the spread of CTX-M genes.

CTX-M gene (No. of isolates)	Inc group (No. of isolates)	Rate*	Resource	Reference
blaCTX-M-1 (119)	N (119)	100%	E. coli from bovine on a dairy farm with high consumption of cephalosporins in Czech Republic, 2008	Dolejska et al., 2011
blaCTX-M-1 (10)	I1 (10)	100%	S. enterica from poultry and humans in France, 2003–08	Cloeckaert et al., 2010
blaCTX-M-3 (14)	L/M (13)	92.9%	Enterobacteriaceae from Bulgaria, Poland and France	Galimand et al., 2005
blaCTX-M-9 (41)	HI2 (24) P1-α (10) FIB (4) HI2, F1 (2) I1 (1)	58.5% 24.4% 9.8% 4.9% 2.4%	Enterobacteriaceae from a university hospital in Spain, 1996–03	Novais et al., 2006
blaCTX-M-14 (40)	K (27) I1 (11) HI2 (2)	67.5% 27.5% 5%	E. coli from patients and healthy volunteers in Spain, 2000–05	Valverde et al., 2009
blaCTX-M-14 (25)	F (8) I1 (5) F, I1 (3) N (1) Q (1)	32% 20% 12% 4% 4%	E. coli from 20 hospitals in 15 provinces in China, 2007–08	Cao et al., 2011
blaCTX-M-14 (23)	FII (13) I1-Iγ (4) FIB (2) FII, I1-Iγ (1) K (1)	56.5% 17.4% 8.7% 4.3% 4.3%	E. coli from outpatients in Hong Kong, 2002–04	Ho et al., 2011
blaCTX-M-15 (18)	FII (17) FI (1)	94.4% 5.6%	E. coli from a hospital in Turkey, 2002–04	Gonullu et al., 2008
blaCTX-M-15 (36)	FI (36)	100%	E. coli from a university hospital in Germany, 2006–07	Mshana et al., 2009
blaCTX-M-15 (55)	FIIA (41) A/C (3) FIIA, A/C (4)	74.5% 5.5% 7.3%	K. pneumoniae from patients in 9 Asian countries, 2008–09	Lee et al., 2011
blaCTX-M-1 (11) blaCTX-M-14 (15) blaCTX-M-15 (19)	N (8) I1 (3) F (9) K (2) F (12) I1 (1) L/M (1) N (1)	72.7% 27.3% 60% 13.3% 63.2% 5.3% 5.3% 5.3%	E. coli from different areas in France, 1997–02	Marcadé et al., 2009
blaCTX-M-1 (7) blaCTX-M-9 (14) blaCTX-M-14 (13) blaCTX-M-15 (4) blaCTX-M-32 (3)	N (5) FII (2) I1 (4) I1, P (3) HI2 (4) FIB (2) K (12) F (4) N (3)	71.4% 28.6% 28.6% 21.4% 28.6% 14.3% 92.3% 100% 100%	E. coli and K. pneumoniae from 11 hospitals in Spain, 2004	Diestra et al., 2009
blaCTX-M-2 (16) blaCTX-M-14 (8)	A/C (11) FVII (1) I1 (1) I1 (6)	68.8% 6.3% 6.3% 75%	E. coli from a survey among 3193 healthy children in Peru & Bolivia, 2005	Pallecchi et al., 2007
blaCTX-M-3 (49) blaCTX-M-15 (11)	I1 (36) FI (8) Y (3) N (2) FI (11)	73.5% 16.3% 6.1% 4.1% 100%	E. coli from faeces of residents in16 nursing homes in the UK, 2004–06	Dhanji et al., 2011a

*Rate = (No. in the 2nd column/No. in the 1st column) × 100%.

Bauernfeind A, Stemplinger I, Jungwirth R, Ernst S, Casellas JM. (1996). Sequences of beta-lactamase genes encoding CTX-M-1 (MEN-1) and CTX-M-2 and relationship of their amino acid sequences with those of other beta-lactamases. Antimicrob Agents Chemother, 40, 509–513.

 PubMed Web of Science ®Google Scholar

al Naiemi N, Bart A, de Jong MD, Vandenbroucke-Grauls CM, Rietra PJ, Debets-Ossenkopp YJ, Wever PC, Spanjaard L, Bos AJ, Duim B. (2006). Widely distributed and predominant CTX-M extended-spectrum beta-lactamases in Amsterdam, The Netherlands. J Clin Microbiol, 44, 3012–3014.

 PubMed Web of Science ®Google Scholar

Komatsu M, Ikeda N, Aihara M, Nakamachi Y, Kinoshita S, Yamasaki K, Shimakawa K. (2001). Hospital outbreak of MEN-1-derived extended spectrum beta-lactamase-producing Klebsiella pneumoniae. J Infect Chemother, 7, 94–101.

 PubMedGoogle Scholar

Rodríguez I, Barownick W, Helmuth R, Mendoza MC, Rodicio MR, Schroeter A, Guerra B. (2009). Extended-spectrum beta-lactamases and AmpC beta-lactamases in ceftiofur-resistant Salmonella enterica isolates from food and livestock obtained in Germany during 2003-07. J Antimicrob Chemother, 64, 301–309.

 PubMed Web of Science ®Google Scholar

Choi SH, Lee JE, Park SJ, Kim MN, Choo EJ, Kwak YG, Jeong JY, Woo JH, Kim NJ, Kim YS. (2007). Prevalence, microbiology, and clinical characteristics of extended-spectrum beta-lactamase-producing Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii in Korea. Eur J Clin Microbiol Infect Dis, 26, 557–561.

 PubMed Web of Science ®Google Scholar

Nagano N, Nagano Y, Cordevant C, Shibata N, Arakawa Y. (2004). Nosocomial transmission of CTX-M-2 beta-lactamase-producing Acinetobacter baumannii in a neurosurgery ward. J Clin Microbiol, 42, 3978–3984.

 PubMed Web of Science ®Google Scholar

Arduino SM, Catalano M, Orman BE, Roy PH, Centrón D. (2003). Molecular epidemiology of orf513-bearing class 1 integrons in multiresistant clinical isolates from Argentinean hospitals. Antimicrob Agents Chemother, 47, 3945–3949.

 PubMed Web of Science ®Google Scholar

Power P, Galleni M, Di Conza J, Ayala JA, Gutkind G. (2005). Description of In116, the first blaCTX-M-2-containing complex class 1 integron found in Morganella morganii isolates from Buenos Aires, Argentina. J Antimicrob Chemother, 55, 461–465.

 PubMed Web of Science ®Google Scholar

Bonnet R, Sampaio JL, Labia R, De Champs C, Sirot D, Chanal C, Sirot J. (2000). A novel CTX-M beta-lactamase (CTX-M-8) in cefotaxime-resistant Enterobacteriaceae isolated in Brazil. Antimicrob Agents Chemother, 44, 1936–1942.

 PubMed Web of Science ®Google Scholar

Minarini LA, Poirel L, Trevisani NA, Darini AL, Nordmann P. (2009). Predominance of CTX-M-type extended-spectrum beta-lactamase genes among enterobacterial isolates from outpatients in Brazil. Diagn Microbiol Infect Dis, 65, 202–206.

 PubMed Web of Science ®Google Scholar

Soler Bistué AJ, Martín FA, Petroni A, Faccone D, Galas M, Tolmasky ME, Zorreguieta A. (2006). Vibrio cholerae InV117, a class 1 integron harboring aac(6′)-Ib and blaCTX-M-2, is linked to transposition genes. Antimicrob Agents Chemother, 50, 1903–1907.

 PubMed Web of Science ®Google Scholar

Gniadkowski M, Schneider I, Palucha A, Jungwirth R, Mikiewicz B, Bauernfeind A. (1998). Cefotaxime-resistant Enterobacteriaceae isolates from a hospital in Warsaw, Poland: identification of a new CTX-M-3 cefotaxime-hydrolyzing beta-lactamase that is closely related to the CTX-M-1/MEN-1 enzyme. Antimicrob Agents Chemother, 42, 827–832.

 PubMed Web of Science ®Google Scholar

Ye Y, Xu XH, Li JB. (2010). Emergence of CTX-M-3, TEM-1 and a new plasmid-mediated MOX-4 AmpC in a multiresistant Aeromonas caviae isolate from a patient with pneumonia. J Med Microbiol, 59, 843–847.

 PubMed Web of Science ®Google Scholar

Yan JJ, Ko WC, Tsai SH, Wu HM, Jin YT, Wu JJ. (2000). Dissemination of CTX-M-3 and CMY-2 beta-lactamases among clinical isolates of Escherichia coli in southern Taiwan. J Clin Microbiol, 38, 4320–4325.

 PubMed Web of Science ®Google Scholar

De Champs C, Sirot D, Chanal C, Bonnet R, Sirot J. (2000). A 1998 survey of extended-spectrum beta-lactamases in Enterobacteriaceae in France. The French Study Group. Antimicrob Agents Chemother, 44, 3177–3179.

 PubMed Web of Science ®Google Scholar

Liu W, Chen L, Li H, Duan H, Zhang Y, Liang X, Li X, Zou M, Xu L, Hawkey PM. (2009). Novel CTX-M beta-lactamase genotype distribution and spread into multiple species of Enterobacteriaceae in Changsha, Southern China. J Antimicrob Chemother, 63, 895–900.

 PubMed Web of Science ®Google Scholar

Baraniak A, Fiett J, Sulikowska A, Hryniewicz W, Gniadkowski M. (2002b). Countrywide spread of CTX-M-3 extended-spectrum beta-lactamase-producing microorganisms of the family Enterobacteriaceae in Poland. Antimicrob Agents Chemother, 46, 151–159.

 PubMed Web of Science ®Google Scholar

Eckert C, Gautier V, Arlet G. (2006). DNA sequence analysis of the genetic environment of various blaCTX-M genes. J Antimicrob Chemother, 57, 14–23.

 PubMed Web of Science ®Google Scholar

Gierczynski R, Szych J, Cieslik A, Rastawicki W, Jagielski M. (2003). The occurrence of the first two CTX-M-3 and TEM-1 producing isolates of Salmonella enterica serovar Oranienburg in Poland. Int J Antimicrob Agents, 21, 497–499.

 PubMed Web of Science ®Google Scholar

Galimand M, Sabtcheva S, Courvalin P, Lambert T. (2005). Worldwide disseminated armA aminoglycoside resistance methylase gene is borne by composite transposon Tn1548. Antimicrob Agents Chemother, 49, 2949–2953.

 PubMed Web of Science ®Google Scholar

Acikgoz ZC, Gulay Z, Bicmen M, Gocer S, Gamberzade S. (2003). CTX-M-3 extended-spectrum beta-lactamase in a Shigella sonnei clinical isolate: first report from Turkey. Scand J Infect Dis, 35, 503–505.

 PubMed Web of Science ®Google Scholar

Gazouli M, Tzelepi E, Sidorenko SV, Tzouvelekis LS. (1998b). Sequence of the gene encoding a plasmid-mediated cefotaxime-hydrolyzing class A beta-lactamase (CTX-M-4): involvement of serine 237 in cephalosporin hydrolysis. Antimicrob Agents Chemother, 42, 1259–1262.

 PubMed Web of Science ®Google Scholar

Bradford PA, Yang Y, Sahm D, Grope I, Gardovska D, Storch G. (1998). CTX-M-5, a novel cefotaxime-hydrolyzing beta-lactamase from an outbreak of Salmonella Typhimurium in Latvia. Antimicrob Agents Chemother, 42, 1980–1984.

 PubMed Web of Science ®Google Scholar

Gazouli M, Tzelepi E, Markogiannakis A, Legakis NJ, Tzouvelekis LS. (1998a). Two novel plasmid-mediated cefotaxime-hydrolyzing beta-lactamases (CTX-M-5 and CTX-M-6) from Salmonella Typhimurium. FEMS Microbiol Lett, 165, 289–293.

 PubMed Web of Science ®Google Scholar

Sabaté M, Tarragó R, Navarro F, Miró E, Vergés C, Barbé J, Prats G. (2000). Cloning and sequence of the gene encoding a novel cefotaxime-hydrolyzing beta-lactamase (CTX-M-9) from Escherichia coli in Spain. Antimicrob Agents Chemother, 44, 1970–1973.

 PubMed Web of Science ®Google Scholar

Chanawong A, M’Zali FH, Heritage J, Xiong JH, Hawkey PM. (2002). Three cefotaximases, CTX-M-9, CTX-M-13, and CTX-M-14, among Enterobacteriaceae in the People’s Republic of China. Antimicrob Agents Chemother, 46, 630–637.

 PubMed Web of Science ®Google Scholar

Ho PL, Shek RH, Chow KH, Duan RS, Mak GC, Lai EL, Yam WC, Tsang KW, Lai WM. (2005b). Detection and characterization of extended-spectrum beta-lactamases among bloodstream isolates of Enterobacter spp. in Hong Kong, 2000-2002. J Antimicrob Chemother, 55, 326–332.

 PubMed Web of Science ®Google Scholar

Alobwede I, M’Zali FH, Livermore DM, Heritage J, Todd N, Hawkey PM. (2003). CTX-M extended-spectrum beta-lactamase arrives in the UK. J Antimicrob Chemother, 51, 470–471.

 PubMed Web of Science ®Google Scholar

García Fernández A, Cloeckaert A, Bertini A, Praud K, Doublet B, Weill FX, Carattoli A. (2007). Comparative analysis of IncHI2 plasmids carrying blaCTX-M-2 or blaCTX-M-9 from Escherichia coli and Salmonella enterica strains isolated from poultry and humans. Antimicrob Agents Chemother, 51, 4177–4180.

 PubMed Web of Science ®Google Scholar

Oliver A, Pérez-Díaz JC, Coque TM, Baquero F, Cantón R. (2001). Nucleotide sequence and characterization of a novel cefotaxime-hydrolyzing beta-lactamase (CTX-M-10) isolated in Spain. Antimicrob Agents Chemother, 45, 616–620.

 PubMed Web of Science ®Google Scholar

Valverde A, Coque TM, Sánchez-Moreno MP, Rollán A, Baquero F, Cantón R. (2004). Dramatic increase in prevalence of fecal carriage of extended-spectrum beta-lactamase-producing Enterobacteriaceae during nonoutbreak situations in Spain. J Clin Microbiol, 42, 4769–4775.

 PubMed Web of Science ®Google Scholar

Cantón R, Oliver A, Coque TM, Varela Mdel C, Pérez-Díaz JC, Baquero F. (2002). Epidemiology of extended-spectrum beta-lactamase-producing Enterobacter isolates in a Spanish hospital during a 12-year period. J Clin Microbiol, 40, 1237–1243.

 PubMed Web of Science ®Google Scholar

Coque TM, Oliver A, Pérez-Díaz JC, Baquero F, Cantón R. (2002). Genes encoding TEM-4, SHV-2, and CTX-M-10 extended-spectrum beta-lactamases are carried by multiple Klebsiella pneumoniae clones in a single hospital (Madrid, 1989 to 2000). Antimicrob Agents Chemother, 46, 500–510.

 PubMed Web of Science ®Google Scholar

Cartelle M, Canle D, Llarena FJ, Molina F, Villanueva R, Bou G. (2006). Characterisation of the first CTX-M-10-producing isolate of Salmonella enterica serotype Virchow. Clin Microbiol Infect, 12, 285–287.

 PubMed Web of Science ®Google Scholar

Kariuki S, Corkill JE, Revathi G, Musoke R, Hart CA. (2001). Molecular characterization of a novel plasmid-encoded cefotaximase (CTX-M-12) found in clinical Klebsiella pneumoniae isolates from Kenya. Antimicrob Agents Chemother, 45, 2141–2143.

 PubMed Web of Science ®Google Scholar

Bae IK, Lee YN, Hwang HY, Jeong SH, Lee SJ, Kwak HS, Song W, Kim HJ, Youn H. (2006b). Emergence of CTX-M-12 extended-spectrum beta-lactamase-producing Escherichia coli in Korea. J Antimicrob Chemother, 58, 1257–1259.

 PubMed Web of Science ®Google Scholar

Song W, Kim J, Bae IK, Jeong SH, Seo YH, Shin JH, Jang SJ, Uh Y, Shin JH, Lee MK, Lee K. (2011). Chromosome-encoded AmpC and CTX-M extended-spectrum ß-lactamases in clinical isolates of Proteus mirabilis from Korea. Antimicrob Agents Chemother, 55, 1414–1419.

 PubMed Web of Science ®Google Scholar

Ho PL, Ho AY, Chow KH, Wong RC, Duan RS, Ho WL, Mak GC, Tsang KW, Yam WC, Yuen KY. (2005a). Occurrence and molecular analysis of extended-spectrum beta-lactamase-producing Proteus mirabilis in Hong Kong, 1999-2002. J Antimicrob Chemother, 55, 840–845.

 PubMed Web of Science ®Google Scholar

Kanamori H, Yano H, Hirakata Y, Endo S, Arai K, Ogawa M, Shimojima M, Aoyagi T, Hatta M, Yamada M, Nishimaki K, Kitagawa M, Kunishima H, Kaku M. (2011). High prevalence of extended-spectrum ß-lactamases and qnr determinants in Citrobacter species from Japan: dissemination of CTX-M-2. J Antimicrob Chemother, 66, 2255–2262.

 PubMed Web of Science ®Google Scholar

Romero L, López L, Martínez-Martínez L, Guerra B, Hernández JR, Pascual A. (2004). Characterization of the first CTX-M-14-producing Salmonella enterica serotype Enteritidis isolate. J Antimicrob Chemother, 53, 1113–1114.

 PubMed Web of Science ®Google Scholar

Pai H, Choi EH, Lee HJ, Hong JY, Jacoby GA. (2001). Identification of CTX-M-14 extended-spectrum beta-lactamase in clinical isolates of Shigella sonnei, Escherichia coli, and Klebsiella pneumoniae in Korea. J Clin Microbiol, 39, 3747–3749.

 PubMed Web of Science ®Google Scholar

Karim A, Poirel L, Nagarajan S, Nordmann P. (2001). Plasmid-mediated extended-spectrum beta-lactamase (CTX-M-3 like) from India and gene association with insertion sequence ISEcp1. FEMS Microbiol Lett, 201, 237–241.

 PubMed Web of Science ®Google Scholar

Shakil S, Khan AU. (2010). Detection of CTX-M-15-producing and carbapenem-resistant Acinetobacter baumannii strains from urine from an Indian hospital. J Chemother, 22, 324–327.

 PubMed Web of Science ®Google Scholar

Gómez-Garcés JL, Saéz D, Almagro M, Fernández-Romero S, Merino F, Campos J, Oteo J. (2011). Osteomyelitis associated to CTX-M-15-producing Aeromonas hydrophila: first description in the literature. Diagn Microbiol Infect Dis, 70, 420–422.

 PubMed Web of Science ®Google Scholar

Kim J, Lim YM, Jeong YS, Seol SY. (2005). Occurrence of CTX-M-3, CTX-M-15, CTX-M-14, and CTX-M-9 extended-spectrum beta-lactamases in Enterobacteriaceae clinical isolates in Korea. Antimicrob Agents Chemother, 49, 1572–1575.

 PubMed Web of Science ®Google Scholar

Moubareck C, Daoud Z, Hakimé NI, Hamzé M, Mangeney N, Matta H, Mokhbat JE, Rohban R, Sarkis DK, Doucet-Populaire F. (2005). Countrywide spread of community- and hospital-acquired extended-spectrum beta-lactamase (CTX-M-15)-producing Enterobacteriaceae in Lebanon. J Clin Microbiol, 43, 3309–3313.

 PubMed Web of Science ®Google Scholar

Lartigue MF, Poirel L, Heritier C, Tolun V, Nordmann P. (2003). First description of CTX-M-15-producing Klebsiella pneumoniae in Turkey. J Antimicrob Chemother, 52, 315–316.

 PubMed Web of Science ®Google Scholar

Zhang Y, Zhou H, Shen XQ, Shen P, Yu YS, Li LJ. (2008). Plasmid-borne armA methylase gene, together with blaCTX-M-15 and blaTEM-1, in a Klebsiella oxytoca isolate from China. J Med Microbiol, 57, 1273–1276.

 PubMed Web of Science ®Google Scholar

Aibinu I, Pfeifer Y, Peters F, Ogunsola F, Adenipekun E, Odugbemi T, Koenig W. (2012). Emergence of blaCTX-M-15, qnrB1 and aac(6′)-Ib-cr resistance genes in Pantoea agglomerans and Enterobacter cloacae from Nigeria (sub-Saharan Africa). J Med Microbiol, 61, 165–167.

 PubMed Web of Science ®Google Scholar

Weill FX, Perrier-Gros-Claude JD, Demartin M, Coignard S, Grimont PA. (2004). Characterization of extended-spectrum-beta-lactamase (CTX-M-15)-producing strains of Salmonella enterica isolated in France and Senegal. FEMS Microbiol Lett, 238, 353–358.

 PubMed Web of Science ®Google Scholar

Baraniak A, Fiett J, Hryniewicz W, Nordmann P, Gniadkowski M. (2002a). Ceftazidime-hydrolysing CTX-M-15 extended-spectrum beta-lactamase (ESBL) in Poland. J Antimicrob Chemother, 50, 393–396.

 PubMed Web of Science ®Google Scholar

Zhang W, Luo Y, Li J, Lin L, Ma Y, Hu C, Jin S, Ran L, Cui S. (2011). Wide dissemination of multidrug-resistant Shigella isolates in China. J Antimicrob Chemother, 66, 2527–2535.

 PubMed Web of Science ®Google Scholar

Hrabák J, Empel J, Gniadkowski M, Halbhuber Z, Rébl K, Urbásková P. (2008). CTX-M-15-producing Shigella sonnei strain from a Czech patient who traveled in Asia. J Clin Microbiol, 46, 2147–2148.

 PubMed Web of Science ®Google Scholar

Bonnet R, Dutour C, Sampaio JL, Chanal C, Sirot D, Labia R, De Champs C, Sirot J. (2001). Novel cefotaximase (CTX-M-16) with increased catalytic efficiency due to substitution Asp-240–>Gly. Antimicrob Agents Chemother, 45, 2269–2275.

 PubMed Web of Science ®Google Scholar

Cao V, Lambert T, Courvalin P. (2002). ColE1-like plasmid pIP843 of Klebsiella pneumoniae encoding extended-spectrum beta-lactamase CTX-M-17. Antimicrob Agents Chemother, 46, 1212–1217.

 PubMed Web of Science ®Google Scholar

Poirel L, Naas T, Le Thomas I, Karim A, Bingen E, Nordmann P. (2001). CTX-M-type extended-spectrum beta-lactamase that hydrolyzes ceftazidime through a single amino acid substitution in the omega loop. Antimicrob Agents Chemother, 45, 3355–3361.

 PubMed Web of Science ®Google Scholar

Saladin M, Cao VT, Lambert T, Donay JL, Herrmann JL, Ould-Hocine Z, Verdet C, Delisle F, Philippon A, Arlet G. (2002). Diversity of CTX-M beta-lactamases and their promoter regions from Enterobacteriaceae isolated in three Parisian hospitals. FEMS Microbiol Lett, 209, 161–168.

 PubMed Web of Science ®Google Scholar

Yu Y, Ji S, Chen Y, Zhou W, Wei Z, Li L, Ma Y. (2007). Resistance of strains producing extended-spectrum beta-lactamases and genotype distribution in China. J Infect, 54, 53–57.

 PubMed Web of Science ®Google Scholar

Liu G, Ling BD, Xie YE, Lin L, Zeng Y, Zhang X, Lei J. (2007). Characterization of CTX-M-22 and TEM-141 encoded by a single plasmid from a clinical isolate of Enterobacter cloacae in China. Jpn J Infect Dis, 60, 295–297.

 PubMed Web of Science ®Google Scholar

Stürenburg E, Kühn A, Mack D, Laufs R. (2004). A novel extended-spectrum beta-lactamase CTX-M-23 with a P167T substitution in the active-site omega loop associated with ceftazidime resistance. J Antimicrob Chemother, 54, 406–409.

 PubMed Web of Science ®Google Scholar

Wu JJ, Chen HM, Ko WC, Wu HM, Tsai SH, Yan JJ. (2008). Prevalence of extended-spectrum beta-lactamases in Proteus mirabilis in a Taiwanese university hospital, 1999 to 2005: identification of a novel CTX-M enzyme (CTX-M-66). Diagn Microbiol Infect Dis, 60, 169–175.

 PubMed Web of Science ®Google Scholar

Munday CJ, Boyd DA, Brenwald N, Miller M, Andrews JM, Wise R, Mulvey MR, Hawkey PM. (2004). Molecular and kinetic comparison of the novel extended-spectrum beta-lactamases CTX-M-25 and CTX-M-26. Antimicrob Agents Chemother, 48, 4829–4834.

 PubMed Web of Science ®Google Scholar

Navon-Venezia S, Chmelnitsky I, Leavitt A, Carmeli Y. (2008). Dissemination of the CTX-M-25 family beta-lactamases among Klebsiella pneumoniae, Escherichia coli and Enterobacter cloacae and identification of the novel enzyme CTX-M-41 in Proteus mirabilis in Israel. J Antimicrob Chemother, 62, 289–295.

 Google Scholar

Brenwald NP, Jevons G, Andrews JM, Xiong JH, Hawkey PM, Wise R. (2003). An outbreak of a CTX-M-type beta-lactamase-producing Klebsiella pneumoniae: the importance of using cefpodoxime to detect extended-spectrum beta-lactamases. J Antimicrob Chemother, 51, 195–196.

 PubMed Web of Science ®Google Scholar

Bonnet R, Recule C, Baraduc R, Chanal C, Sirot D, De Champs C, Sirot J. (2003). Effect of D240G substitution in a novel ESBL CTX-M-27. J Antimicrob Chemother, 52, 29–35.

 PubMed Web of Science ®Google Scholar

Bouallègue-Godet O, Ben Salem Y, Fabre L, Demartin M, Grimont PA, Mzoughi R, Weill FX. (2005). Nosocomial outbreak caused by Salmonella enterica serotype Livingstone producing CTX-M-27 extended-spectrum beta-lactamase in a neonatal unit in Sousse, Tunisia. J Clin Microbiol, 43, 1037–1044.

 PubMed Web of Science ®Google Scholar

Hasman H, Mevius D, Veldman K, Olesen I, Aarestrup FM. (2005). beta-Lactamases among extended-spectrum beta-lactamase (ESBL)-resistant Salmonella from poultry, poultry products and human patients in The Netherlands. J Antimicrob Chemother, 56, 115–121.

 PubMed Web of Science ®Google Scholar

Abdalhamid B, Pitout JD, Moland ES, Hanson ND. (2004). Community-onset disease caused by Citrobacter freundii producing a novel CTX-M beta-lactamase, CTX-M-30, in Canada. Antimicrob Agents Chemother, 48, 4435–4437.

 PubMed Web of Science ®Google Scholar

Quinteros M, Radice M, Gardella N, Rodriguez MM, Costa N, Korbenfeld D, Couto E, Gutkind G; Microbiology Study Group. (2003). Extended-spectrum beta-lactamases in enterobacteriaceae in Buenos Aires, Argentina, public hospitals. Antimicrob Agents Chemother, 47, 2864–2867.

 PubMed Web of Science ®Google Scholar

Cartelle M, del Mar Tomas M, Molina F, Moure R, Villanueva R, Bou G. (2004). High-level resistance to ceftazidime conferred by a novel enzyme, CTX-M-32, derived from CTX-M-1 through a single Asp240-Gly substitution. Antimicrob Agents Chemother, 48, 2308–2313.

 PubMed Web of Science ®Google Scholar

Mendonça N, Ferreira E, Louro D, Caniça M; ARSIP Participants. (2009). Molecular epidemiology and antimicrobial susceptibility of extended- and broad-spectrum beta-lactamase-producing Klebsiella pneumoniae isolated in Portugal. Int J Antimicrob Agents, 34, 29–37.

 PubMed Web of Science ®Google Scholar

Fernández A, Gil E, Cartelle M, Pérez A, Beceiro A, Mallo S, Tomás MM, Pérez-Llarena FJ, Villanueva R, Bou G. (2007). Interspecies spread of CTX-M-32 extended-spectrum beta-lactamase and the role of the insertion sequence IS1 in down-regulating blaCTX-M gene expression. J Antimicrob Chemother, 59, 841–847.

 PubMed Web of Science ®Google Scholar

Galani I, Souli M, Chryssouli Z, Giamarellou H. (2007). Detection of CTX-M-15 and CTX-M-33, a novel variant of CTX-M-15, in clinical Escherichia coli isolates in Greece. Int J Antimicrob Agents, 29, 598–600.

 PubMed Web of Science ®Google Scholar

Miró E, Mirelis B, Navarro F, Rivera A, Mesa RJ, Roig MC, Gómez L, Coll P. (2005). Surveillance of extended-spectrum beta-lactamases from clinical samples and faecal carriers in Barcelona, Spain. J Antimicrob Chemother, 56, 1152–1155.

 PubMed Web of Science ®Google Scholar

Tian GB, Adams-Haduch JM, Qureshi ZA, Wang HN, Doi Y. (2010). CTX-M-35 extended-spectrum beta-lactamase conferring ceftazidime resistance in Citrobacter koseri. Int J Antimicrob Agents, 35, 412–413.

 PubMed Web of Science ®Google Scholar

Govinden U, Mocktar C, Moodley P, Sturm AW, Essack SY. (2006). CTX-M-37 in Salmonella enterica serotype Isangi from Durban, South Africa. Int J Antimicrob Agents, 28, 288–291.

 PubMed Web of Science ®Google Scholar

Chmelnitsky I, Carmeli Y, Leavitt A, Schwaber MJ, Navon-Venezia S. (2005). CTX-M-2 and a new CTX-M-39 enzyme are the major extended-spectrum beta-lactamases in multiple Escherichia coli clones isolated in Tel Aviv, Israel. Antimicrob Agents Chemother, 49, 4745–4750.

 PubMed Web of Science ®Google Scholar

Hopkins KL, Deheer-Graham A, Threlfall EJ, Batchelor MJ, Liebana E. (2006). Novel plasmid-mediated CTX-M-8 subgroup extended-spectrum beta-lactamase (CTX-M-40) isolated in the UK. Int J Antimicrob Agents, 27, 572–575.

 PubMed Web of Science ®Google Scholar

Stepanova MN, Pimkin M, Nikulin AA, Kozyreva VK, Agapova ED, Edelstein MV. (2008). Convergent in vivo and in vitro selection of ceftazidime resistance mutations at position 167 of CTX-M-3 beta-lactamase in hypermutable Escherichia coli strains. Antimicrob Agents Chemother, 52, 1297–1301.

 PubMed Web of Science ®Google Scholar

Celenza G, Pellegrini C, Caccamo M, Segatore B, Amicosante G, Perilli M. (2006). Spread of blaCTX-M-type and blaPER-2 beta-lactamase genes in clinical isolates from Bolivian hospitals. J Antimicrob Chemother, 57, 975–978.

 PubMed Web of Science ®Google Scholar

Ishii Y, Ohno A, Taguchi H, Imajo S, Ishiguro M, Matsuzawa H. (1995). Cloning and sequence of the gene encoding a cefotaxime-hydrolyzing class A beta-lactamase isolated from Escherichia coli. Antimicrob Agents Chemother, 39, 2269–2275.

 PubMed Web of Science ®Google Scholar

Ma L, Ishii Y, Ishiguro M, Matsuzawa H, Yamaguchi K. (1998). Cloning and sequencing of the gene encoding Toho-2, a class A beta-lactamase preferentially inhibited by tazobactam. Antimicrob Agents Chemother, 42, 1181–1186.

 PubMed Web of Science ®Google Scholar

Cheng J, Ye Y, Wang YY, Li H, Li X, Li JB. (2008). Phenotypic and molecular characterization of 5 novel CTX-M enzymes carried by Klebsiella pneumoniae and Escherichia coli. Acta Pharmacol Sin, 29, 217–225.

 PubMed Web of Science ®Google Scholar

Doublet B, Granier SA, Robin F, Bonnet R, Fabre L, Brisabois A, Cloeckaert A, Weill FX. (2009). Novel plasmid-encoded ceftazidime-hydrolyzing CTX-M-53 extended-spectrum beta-lactamase from Salmonella enterica serotypes Westhampton and Senftenberg. Antimicrob Agents Chemother, 53, 1944–1951.

 PubMed Web of Science ®Google Scholar

Bae IK, Lee BH, Hwang HY, Jeong SH, Hong SG, Chang CL, Kwak HS, Kim HJ, Youn H. (2006a). A novel ceftazidime-hydrolysing extended-spectrum beta-lactamase, CTX-M-54, with a single amino acid substitution at position 167 in the omega loop. J Antimicrob Chemother, 58, 315–319.

 PubMed Web of Science ®Google Scholar

Kiratisin P, Apisarnthanarak A, Saifon P, Laesripa C, Kitphati R, Mundy LM. (2007). The emergence of a novel ceftazidime-resistant CTX-M extended-spectrum beta-lactamase, CTX-M-55, in both community-onset and hospital-acquired infections in Thailand. Diagn Microbiol Infect Dis, 58, 349–355.

 PubMed Web of Science ®Google Scholar

Pallecchi L, Bartoloni A, Fiorelli C, Mantella A, Di Maggio T, Gamboa H, Gotuzzo E, Kronvall G, Paradisi F, Rossolini GM. (2007). Rapid dissemination and diversity of CTX-M extended-spectrum beta-lactamase genes in commensal Escherichia coli isolates from healthy children from low-resource settings in Latin America. Antimicrob Agents Chemother, 51, 2720–2725.

 PubMed Web of Science ®Google Scholar

Hopkins KL, Threlfall EJ, Karisik E, Wardle JK. (2008). Identification of novel plasmid-mediated extended-spectrum beta-lactamase CTX-M-57 in Salmonella enterica serovar Typhimurium. Int J Antimicrob Agents, 31, 85–86.

 PubMed Web of Science ®Google Scholar

de Oliveira Garcia D, Doi Y, Szabo D, Adams-Haduch JM, Vaz TM, Leite D, Padoveze MC, Freire MP, Silveira FP, Paterson DL. (2008). Multiclonal outbreak of Klebsiella pneumoniae producing extended-spectrum beta-lactamase CTX-M-2 and novel variant CTX-M-59 in a neonatal intensive care unit in Brazil. Antimicrob Agents Chemother, 52, 1790–1793.

 PubMed Web of Science ®Google Scholar

Brasme L, Nordmann P, Fidel F, Lartigue MF, Bajolet O, Poirel L, Forte D, Vernet-Garnier V, Madoux J, Reveil JC, Alba-Sauviat C, Baudinat I, Bineau P, Bouquigny-Saison C, Eloy C, Lafaurie C, Siméon D, Verquin JP, Noël F, Strady C, De Champs C. (2007). Incidence of class A extended-spectrum beta-lactamases in Champagne-Ardenne (France): a 1 year prospective study. J Antimicrob Chemother, 60, 956–964.

 PubMed Web of Science ®Google Scholar

Zong Z, Partridge SR, Thomas L, Iredell JR. (2008). Dominance of blaCTX-M within an Australian extended-spectrum beta-lactamase gene pool. Antimicrob Agents Chemother, 52, 4198–4202.

 PubMed Web of Science ®Google Scholar

Pornruangwong S, Hendriksen RS, Pulsrikarn C, Bangstrakulnonth A, Mikoleit M, Davies RH, Aarestrup FM, Garcia-Migura L. (2011). Epidemiological investigation of Salmonella enterica serovar Kedougou in Thailand. Foodborne Pathog Dis, 8, 203–211.

 PubMed Web of Science ®Google Scholar

Nagano Y, Nagano N, Wachino J, Ishikawa K, Arakawa Y. (2009). Novel chimeric beta-lactamase CTX-M-64, a hybrid of CTX-M-15-like and CTX-M-14 beta-lactamases, found in a Shigella sonnei strain resistant to various oxyimino-cephalosporins, including ceftazidime. Antimicrob Agents Chemother, 53, 69–74.

 PubMed Web of Science ®Google Scholar

Sun Y, Zeng Z, Chen S, Ma J, He L, Liu Y, Deng Y, Lei T, Zhao J, Liu JH. (2010). High prevalence of blaCTX-M extended-spectrum ß-lactamase genes in Escherichia coli isolates from pets and emergence of CTX-M-64 in China. Clin Microbiol Infect, 16, 1475–1481.

 PubMed Web of Science ®Google Scholar

Doi Y, Adams-Haduch JM, Paterson DL. (2008). Escherichia coli isolate coproducing 16S rRNA Methylase and CTX-M-type extended-spectrum beta-lactamase isolated from an outpatient in the United States. Antimicrob Agents Chemother, 52, 1204–1205.

 PubMed Web of Science ®Google Scholar

Oteo J, Delgado-Iribarren A, Vega D, Bautista V, Rodríguez MC, Velasco M, Saavedra JM, Pérez-Vázquez M, García-Cobos S, Martínez-Martínez L, Campos J. (2008). Emergence of imipenem resistance in clinical Escherichia coli during therapy. Int J Antimicrob Agents, 32, 534–537.

 PubMed Web of Science ®Google Scholar

Heffernan HM, Woodhouse RE, Pope CE, Blackmore TK. (2009). Prevalence and types of extended-spectrum beta-lactamases among urinary Escherichia coli and Klebsiella spp. in New Zealand. Int J Antimicrob Agents, 34, 544–549.

 PubMed Web of Science ®Google Scholar

Schneider I, Queenan AM, Markovska R, Markova B, Keuleyan E, Bauernfeind A. (2009). New variant of CTX-M-type extended-spectrum beta-lactamases, CTX-M-71, with a Gly238Cys substitution in a Klebsiella pneumoniae isolate from Bulgaria. Antimicrob Agents Chemother, 53, 4518–4521.

 PubMed Web of Science ®Google Scholar

Cheng J, Wang Q, Chen Y, Ye Y, Li H, Li X, Li JB. (2009). Phenotypic and molecular characterization of a novel beta-lactamase carried by Klebsiella pneumoniae, CTX-M-72, derived from CTX-M-3. J Gen Appl Microbiol, 55, 207–216.

 PubMed Web of Science ®Google Scholar

Rodríguez MM, Power P, Sader H, Galleni M, Gutkind G. (2010). Novel chromosome-encoded CTX-M-78 beta-lactamase from a Kluyvera georgiana clinical isolate as a putative origin of CTX-M-25 subgroup. Antimicrob Agents Chemother, 54, 3070–3071.

 PubMed Web of Science ®Google Scholar

Tian SF, Chen BY, Chu YZ, Wang S. (2008). Prevalence of rectal carriage of extended-spectrum beta-lactamase-producing Escherichia coli among elderly people in community settings in China. Can J Microbiol, 54, 781–785.

 PubMed Web of Science ®Google Scholar

Cheng J, Gao W, Yin J, Sun Z, Ye Y, Gao YF, Li X, Li JB. (2010). Phenotypic and molecular characterization of two novel CTX-M enzymes carried by Klebsiella pneumoniae. Mol Biol Rep, 37, 1261–1267.

 PubMed Web of Science ®Google Scholar

Cui S, Li J, Sun Z, Hu C, Jin S, Li F, Guo Y, Ran L, Ma Y. (2009). Characterization of Salmonella enterica isolates from infants and toddlers in Wuhan, China. J Antimicrob Chemother, 63, 87–94.

 PubMed Web of Science ®Google Scholar

Yin J, Cheng J, Sun Z, Ye Y, Gao YF, Li JB, Zhang XJ. (2009). Characterization of two plasmid-encoded cefotaximases found in clinical Escherichia coli isolates: CTX-M-65 and a novel enzyme, CTX-M-87. J Med Microbiol, 58, 811–815.

 PubMed Web of Science ®Google Scholar

Ranjbar R, Giammanco GM, Aleo A, Plano MR, Naghoni A, Owlia P, Mammina C. (2010). Characterization of the first extended-spectrum beta-lactamase-producing nontyphoidal Salmonella strains isolated in Tehran, Iran. Foodborne Pathog Dis, 7, 91–95.

 PubMed Web of Science ®Google Scholar

McGettigan SE, Hu B, Andreacchio K, Nachamkin I, Edelstein PH. (2009). Prevalence of CTX-M beta-lactamases in Philadelphia, Pennsylvania. J Clin Microbiol, 47, 2970–2974.

 PubMed Web of Science ®Google Scholar

Seputiene V, Linkevicius M, Bogdaite A, Povilonis J, Planciuniene R, Giedraitiene A, Pavilonis A, Suziedeliene E. (2010). Molecular characterization of extended-spectrum ß-lactamase-producing Escherichia coli and Klebsiella pneumoniae isolates from hospitals in Lithuania. J Med Microbiol, 59, 1263–1265.

 PubMed Web of Science ®Google Scholar

Djamdjian L, Naas T, Tandé D, Cuzon G, Hanrotel-Saliou C, Nordmann P. (2011). CTX-M-93, a CTX-M variant lacking penicillin hydrolytic activity. Antimicrob Agents Chemother, 55, 1861–1866.

 PubMed Web of Science ®Google Scholar

Jacoby G, Bush K. (2012). β-Lactamase classification and amino acid sequences for TEM, SHV and OXA extended-spectrum and inhibitor resistant enzymes. http://www.lahey.org/Studies/. Accessed on 1 March, 2012.

 Google Scholar

Diestra K, Juan C, Curiao T, Moyá B, Miró E, Oteo J, Coque TM, Pérez-Vázquez M, Campos J, Cantón R, Oliver A, Navarro F; Red Española de Investigación en Patología Infecciosa (REIPI), Spain. (2009). Characterization of plasmids encoding blaESBL and surrounding genes in Spanish clinical isolates of Escherichia coli and Klebsiella pneumoniae. J Antimicrob Chemother, 63, 60–66.

 Google Scholar

Cullik A, Pfeifer Y, Prager R, von Baum H, Witte W. (2010). A novel IS26 structure surrounds blaCTX-M genes in different plasmids from German clinical Escherichia coli isolates. J Med Microbiol, 59, 580–587.

 PubMed Web of Science ®Google Scholar

Su Z, Dai X, Chen J, Kong F, Wang H, Li Y, Peng S, Wang S, Shao Q, Lv L, Xu H. (2008). The blaCTX-M-1 gene located in a novel complex class I integron bearing an ISCR1 element in Escherichia coli isolates from Zhenjiang, China. J Antimicrob Chemother, 62, 1150–1151.

 PubMed Web of Science ®Google Scholar

Arduino SM, Roy PH, Jacoby GA, Orman BE, Pineiro SA, Centron D. (2002). blaCTX-M-2 is located in an unusual class 1 integron (In35) which includes Orf513. Antimicrob Agents Chemother, 46, 2303–2306.

 PubMed Web of Science ®Google Scholar

Valverde A, Cantón R, Galán JC, Nordmann P, Baquero F, Coque TM. (2006). In117, an unusual In0-like class 1 integron containing CR1 and blaCTX-M-2 and associated with a Tn21-like element. Antimicrob Agents Chemother, 50, 799–802.

 PubMed Web of Science ®Google Scholar

Harada S, Ishii Y, Saga T, Kouyama Y, Tateda K, Yamaguchi K. (2012). Chromosomal integration and location on IncT plasmids of the blaCTX-M-2 gene in Proteus mirabilis clinical isolates. Antimicrob Agents Chemother, 56, 1093–1096.

 PubMed Web of Science ®Google Scholar

Lartigue MF, Poirel L, Nordmann P. (2004). Diversity of genetic environment of blaCTX-M genes. FEMS Microbiol Lett, 234, 201–207.

 PubMed Web of Science ®Google Scholar

Sabaté M, Navarro F, Miró E, Campoy S, Mirelis B, Barbé J, Prats G. (2002). Novel complex sul1-type integron in Escherichia coli carrying blaCTX-M-9. Antimicrob Agents Chemother, 46, 2656–2661.

 PubMed Web of Science ®Google Scholar

Oliver A, Coque TM, Alonso D, Valverde A, Baquero F, Cantón R. (2005). CTX-M-10 linked to a phage-related element is widely disseminated among Enterobacteriaceae in a Spanish hospital. Antimicrob Agents Chemother, 49, 1567–1571.

 PubMed Web of Science ®Google Scholar

Izumiya H, Mori K, Higashide M, Tamura K, Takai N, Hirose K, Terajima J, Watanabe H. (2005). Identification of CTX-M-14 beta-lactamase in a Salmonella enterica serovar Enteritidis isolate from Japan. Antimicrob Agents Chemother, 49, 2568–2570.

 PubMed Web of Science ®Google Scholar

Billard-Pomares T, Tenaillon O, Le Nagard H, Rouy Z, Cruveiller S, Médigue C, Arlet G, Denamur E, Branger C. (2011). Complete nucleotide sequence of plasmid pTN48, encoding the CTX-M-14 extended-spectrum ß-lactamase from an Escherichia coli O102-ST405 strain. Antimicrob Agents Chemother, 55, 1270–1273.

 PubMed Web of Science ®Google Scholar

Bae IK, Lee YN, Lee WG, Lee SH, Jeong SH. (2007). Novel complex class 1 integron bearing an ISCR1 element in an Escherichia coli isolate carrying the blaCTX-M-14 gene. Antimicrob Agents Chemother, 51, 3017–3019.

 PubMed Web of Science ®Google Scholar

Bae IK, Lee YH, Jeong HJ, Hong SG, Lee SH, Jeong SH. (2008). A novel blaCTX-M-14 gene-harboring complex class 1 integron with an In4-like backbone structure from a clinical isolate of Escherichia coli. Diagn Microbiol Infect Dis, 62, 340–342.

 PubMed Web of Science ®Google Scholar

Fabre L, Delauné A, Espié E, Nygard K, Pardos M, Polomack L, Guesnier F, Galimand M, Lassen J, Weill FX. (2009). Chromosomal integration of the extended-spectrum beta-lactamase gene blaCTX-M-15 in Salmonella enterica serotype Concord isolates from internationally adopted children. Antimicrob Agents Chemother, 53, 1808–1816.

 PubMed Web of Science ®Google Scholar

Poirel L, Decousser JW, Nordmann P. (2003). Insertion sequence ISEcp1B is involved in expression and mobilization of a blaCTX-M beta-lactamase gene. Antimicrob Agents Chemother, 47, 2938–2945.

 PubMed Web of Science ®Google Scholar

Zong Z, Partridge SR, Iredell JR. (2010). ISEcp1-mediated transposition and homologous recombination can explain the context of blaCTX-M-62 linked to qnrB2. Antimicrob Agents Chemother, 54, 3039–3042.

 PubMed Web of Science ®Google Scholar

Dolejska M, Jurcickova Z, Literak I, Pokludova L, Bures J, Hera A, Kohoutova L, Smola J, Cizek A. (2011). IncN plasmids carrying blaCTX-M-1 in Escherichia coli isolates on a dairy farm. Vet Microbiol, 149, 513–516.

 PubMed Web of Science ®Google Scholar

Cloeckaert A, Praud K, Lefevre M, Doublet B, Pardos M, Granier SA, Brisabois A, Weill FX. (2010). IncI1 plasmid carrying extended-spectrum-beta-lactamase gene blaCTX-M-1 in Salmonella enterica isolates from poultry and humans in France, 2003 to 2008. Antimicrob Agents Chemother, 54, 4484–4486.

 PubMed Web of Science ®Google Scholar

Novais A, Cantón R, Valverde A, Machado E, Galán JC, Peixe L, Carattoli A, Baquero F, Coque TM. (2006). Dissemination and persistence of blaCTX-M-9 are linked to class 1 integrons containing CR1 associated with defective transposon derivatives from Tn402 located in early antibiotic resistance plasmids of IncHI2, IncP1-alpha, and IncFI groups. Antimicrob Agents Chemother, 50, 2741–2750.

 PubMed Web of Science ®Google Scholar

Valverde A, Cantón R, Garcillán-Barcia MP, Novais A, Galán JC, Alvarado A, de la Cruz F, Baquero F, Coque TM. (2009). Spread of blaCTX-M-14 is driven mainly by IncK plasmids disseminated among Escherichia coli phylogroups A, B1, and D in Spain. Antimicrob Agents Chemother, 53, 5204–5212.

 PubMed Web of Science ®Google Scholar

Cao X, Cavaco LM, Lv Y, Li Y, Zheng B, Wang P, Hasman H, Liu Y, Aarestrup FM. (2011). Molecular characterization and antimicrobial susceptibility testing of Escherichia coli isolates from patients with urinary tract infections in 20 Chinese hospitals. J Clin Microbiol, 49, 2496–2501.

 PubMed Web of Science ®Google Scholar

Ho PL, Lo WU, Wong RC, Yeung MK, Chow KH, Que TL, Tong AH, Bao JY, Lok S, Wong SS. (2011). Complete sequencing of the FII plasmid pHK01, encoding CTX-M-14, and molecular analysis of its variants among Escherichia coli from Hong Kong. J Antimicrob Chemother, 66, 752–756.

 PubMed Web of Science ®Google Scholar

Gonullu N, Aktas Z, Kayacan CB, Salcioglu M, Carattoli A, Yong DE, Walsh TR. (2008). Dissemination of CTX-M-15 beta-lactamase genes carried on Inc FI and FII plasmids among clinical isolates of Escherichia coli in a university hospital in Istanbul, Turkey. J Clin Microbiol, 46, 1110–1112.

 PubMed Web of Science ®Google Scholar

Mshana SE, Imirzalioglu C, Hossain H, Hain T, Domann E, Chakraborty T. (2009). Conjugative IncFI plasmids carrying CTX-M-15 among Escherichia coli ESBL producing isolates at a University hospital in Germany. BMC Infect Dis, 9, 97.

 PubMed Web of Science ®Google Scholar

Lee MY, Ko KS, Kang CI, Chung DR, Peck KR, Song JH. (2011). High prevalence of CTX-M-15-producing Klebsiella pneumoniae isolates in Asian countries: diverse clones and clonal dissemination. Int J Antimicrob Agents, 38, 160–163.

 PubMed Web of Science ®Google Scholar

Marcadé G, Deschamps C, Boyd A, Gautier V, Picard B, Branger C, Denamur E, Arlet G. (2009). Replicon typing of plasmids in Escherichia coli producing extended-spectrum beta-lactamases. J Antimicrob Chemother, 63, 67–71.

 PubMed Web of Science ®Google Scholar

Dhanji H, Doumith M, Rooney PJ, O’Leary MC, Loughrey AC, Hope R, Woodford N, Livermore DM. (2011a). Molecular epidemiology of fluoroquinolone-resistant ST131 Escherichia coli producing CTX-M extended-spectrum beta-lactamases in nursing homes in Belfast, UK. J Antimicrob Chemother, 66, 297–303.

 Google Scholar