Molecular characterization of carbapenem-resistant Gram-negative bacilli clinical isolates in Algeria

Figures & data

Table 1 Antimicrobial resistance patterns of Gram-negative bacilli clinical isolates according to species (A) and patient types (B)

Antibiotics	(A)				(B)
	Resistance pattern (%)				Patient types ^a		P values ^b
	Enterobacteriaceae (n=47)		Non-Enterobacteriaceae (n=21)		Inpatients (n=29)	Outpatients (n=39)
	Escherichia coli (n=27)	Klebsiella pneumoniae (n=20)	Pseudomonas aeruginosa (n=9)	Acinetobacter baumannii (n=12)
TIC	25 (92.6)	19 (95)	8 (88.9)	11 (91.7)	29	34	0.1
TCC	24 (88.9)	15 (75)	8 (88.9)	11 (91.7)	28	30	0.04
CAZ	9 (33.3)	17 (85)	7 (77.8)	11 (91.7)	23	21	0.02
CRO	9 (33.3)	16 (80)	Nd	Nd	18^c	7^c	< l0^-3c
FEP	5 (18.5)	16 (80)	5 (55.5)	9 (75)	21	14	0.002
ATM	7 (26)	15 (75)	5 (55.5)	9 (75)	21	15	0.005
ETP	1 (3.7)	4 (20)	Nd	Nd	3^c	2^c	0.5^c
IPM	0	2 (10)	2 (22.2)	6 (50)	10	0	<10^-3
GN	9 (33.3)	14 (70)	5 (55.5)	8 (66.7)	18	18	0.2
AMK	0	1 (5)	0	4 (33.3)	5	0	0.02
CIP	15 (55.5)	14 (70)	7 (77.8)	11 (91.7)	24	23	0.03
FOF	0	12 (60)	7 (77.8)	Nd	17^d	2d	<l0^-3d
SXT	23 (85.2)	14 (70)	Nd	12 (100)	26^e	23^e	0.02^e
CT	0	0	0	0	0	0	Nd

Notes: ^aGNB strains were isolated from 29 inpatients (E. coli n=8, K. pneumoniae n=10, P. aeruginosa n=3, and A. baumannii n=8) and 39 outpatients (E. coli n=19, K. pneumoniae n=10, P. aeruginosa n=6, and A. baumannii n=4).

b Statistical tests were performed using two-sided Pearson ×2 or Fisher’s exact test, as appropriate, comparing the levels of antibiotic resistance between hospitalized and external patients.

c P-values for CRO and ETP were evaluated only for Enterobacteriaceae isolates.

d P-values for FOF were evaluated only for Enterobacteriaceae and P. aeruginosa strains.

e P-values for SXT were evaluated only for Enterobacteriaceae and A. baumannii isolates.

Abbreviations: TIC, ticarcillin; TCC, ticarcillin/clavulanic acid; CAZ, ceftazidime; CRO, ceftriaxone; FEP, cefepime; ATM, aztreonam; ETP, ertapenem; IPM, imipenem; GN, gentamicin; AMK, amikacin; CIP, ciprofloxacin; FOF, fosfomycin; SXT, trimethoprim/sulfamethoxazole; CT, colistin; Nd, not determined.

Table 2 Phenotypic and genotypic features of carbapenem-resistant Gram-negative bacilli clinical isolates

GNB clinical isolates	Sources	Ward	Sample source	Resistance phenotype	IMP MIC (µg/mL)	Phenotypic detection of carbapenemase			β-Lactamases genes	Carbapenems resistance genes	Sequence type
Enterobacteriaceae						MCNP	MHT	EDTA
Escherichia coli (S 14)	Community	/	Urine	TIC.TCC.ETP	<0.25	+	+	-	-	OXA-48	533
Klebsiella pneumoniae (S4)	Hospital	Pediatrics	Blood	TIC.TCC.CAZ.CRO.FEP.ATM.EPT.IMP.GN.CIP.FOF.SXT	3	+	+	-	CTX-M-15, SHV-1 1	OXA-48	101
K pneumoniae (S20)	Hospital	Pediatrics	Blood	TIC.TCC.CAZ.CRO.FEP.ATM.EPT.IMP.GN.CIP.FOF.SXT	3	+	+	-	-	OXA-48	2017
K pneumoniae (S50)	Community	/	Urine	TIC.TCC.EPT	<0.25	+	+	-	-	OXA-48	163
K pneumoniae (S 12)	Hospital	Urology	Urine	TIC.TCC.CAZ.CRO.FEP.ATM.EPT.GN.CIP.FOF.SXT	<0.25	+	+	-	TEM-1,CTX-M-15	OXA-48	147
Non-EnterobacteriaceaePseudomonas aeruginosa (S 1)	Hospital	Urology	Urine	TIC.TCC.CAZ.FEP.ATM.IMP.GN.CIP.FOF	>32	-	-	-	SHV-1 1	OprD (PI)	654
P. aeruginosa (S2)	Hospital	Pediatrics	Urine	TIC.TCC.CAZ.FEP.ATM.IMP.CIP.FOF	>32	-	-	-	SHV-1 1	OprD (P2)	654
Acinetobacter baumannii (A1)	Hospital	ICU	Blood	TIC.TCC.CAZ.FEP.ATM.IMP.GN.AMK.CIP.SXT	>32	+	+	-	TEM-1	OXA-23	2
A. baumannii (A2)	Hospital	Urology	Urine	TIC.TCC.CAZ.FEP.ATM.IMP.GN.CIP.SXT	>32	+	+	-	TEM-1	OXA-23	2
A. baumannii (A3)	Hospital	Pediatrics	CSF	TIC.TCC.CAZ.FEP.ATM.IMP.GN.AMK.CIP.SXT	>32	+	+	-	TEM-1	OXA-23	2
A. baumannii (A4)	Hospital	ICU	Urine	TIC.TCC.CAZ.FEP.ATM.IMP.GN.AMK.CIP.SXT	>32	+	+	-	TEM-1D	OXA-23	2
A. baumannii (A5)	Hospital	General surgery	Blood	TIC.TCC.CAZ.FEP.ATM.IMP.GN.CIP.SXT	>32	+	+	-	TEM-1D	OXA-23	2
A. baumannii (A6)	Hospital	Pediatrics	Urine	TIC.TCC.CAZ.FEP.ATM.IMP.GN.CIP.SXT	>32	+	+	-	-	OXA-23	2

Notes: P1: several mutation types leading to the premature stop codon TGA in oprD, resulting in a truncated polypeptide of 83 amino acid residues; P2: several mutation types leading to the premature stop codon TAG in oprD, resulting in a truncated polypeptide of 414 amino acid residues.

Abbreviations: TIC, ticarcillin; TCC, ticarcillin/clavulanic acid; ETP, ertapenem; CAZ, ceftazidime; CRO, ceftriaxone; FEP, cefepime; ATM, aztreonam; IPM, imipenem; GN, gentamicin; AMK, amikacin; CIP, ciprofloxacin; FOF, fosfomycin; SXT, trimethoprim/sulfamethoxazole; ICU, intensive care unit; MIC, minimum inhibitory concentration; MCNP, modified Carba NP; MHT, modified Hodge test; EDTA, ethylene diamine tetra-acetic acid; CSF, cerebrospinal fluid.