Antimicrobial resistance pattern and molecular genetic distribution of metallo-β-lactamases producing Pseudomonas aeruginosa isolated from hospitals in Minia, Egypt

Figures & data

Table 1 PCR primers used for detection of ESBL-CTX-M₁₅ and MBL genes in Pseudomonas aeruginosa

Gene	Primers	Sequence	Product size
ESBL-CTXM15	CTX-M15-F	5'-CGTCACGCTGTTGTTAGGAA-'3	780 bp
	CTX-M15-R	5'-ACGGCTTTCTGCCTTAGGTT-3'
blaVIM	VIM-F	5'-GATGGTGTT TGG TCG CAT A-3'	390 bp
	VIM-R	5'-CGA ATG CGC AGC ACC AG-3'
blaIMP	IMP-F	5'GGAATAGAGTGGCTTAATTCTC3'	188 bp
	IMP-R	5'-CCAAACCACTACGTTATCT-3'
blaGIM	GIM-F	5'-TCG ACA CAC CTT GGT CTG AA 3'	477 bp
	GIM-R	5'-AAC TTC CAA CTT TGC CAT GC-3'	271 bp
blaSPM	SPM-F	5'-AAA ATC TGG GTA CGC AAA CG-3'
	SPM-R	5'-ACA TTA TCC GCT GGA ACA GG-3'

Abbreviations: ESBL, extended-spectrum β-lactamase; MBL, metallo-β-lactamase; IMP, imipenemase; VIM, Verona integron–encoded MBL; GIM, German imipenemase MBL; SPM, S>o Paulo MBL.

Figure 1 Prevalence of Pseudomonas aeruginosa isolated from different hospitals in Minia.

Figure 2 Resistance pattern of Pseudomonas aeruginosa isolates to different antimicrobial agents.

Table 2 Antibiotic-resistance patterns of ESBL- and MBL-producing strains

	% Resistance
	ESBL-producing P. aeruginosa (n=54)	MBL-producing P. aeruginosa (n=11)
Azlocillin	100	100
Amoxicillin– clavulanic acid	100	100
Ampicillin/sulbactam	100	100
Tobramycin	81.5	45.5
Aztreonam	83.3	54.5
Cefepime	100	72.7
Polymyxin B	74.1	54.5
Cefoperazone	90.8	54.5
Colistin sulfate	37	36.4
Levofloxacin	55.6	36.4
Amikacin	55.6	63.6
Ciprofloxacin	35.2	36.4
Piperacillin	51.9	54.5
Gentamicin	46.3	63.6
Imipenem	5.6	100
Meropenem	7.4	100
Carbenicillin	46.3	72.7
Tigecycline	42.6	45.5

Abbreviations: ESBL, extended-spectrum β-lactamase; MBL, metallo-β-lactamase; P. aeruginosa, Pseudomonas aeruginosa.

Table 3 Distribution of ESBL- and MBL-producing isolates among MDR Pseudomonas aeruginosa isolates from different clinical specimens

Type of infection	MDR P. aeruginosa	ESBLs		MBL
		n	%	n	%
Wound	59	24	40%	4	19%
Ear	20	16	80%	3	14.3%
Burns	2	1	50%	—	—
Urinary tract	2	1	50%	—	—
Chest	4	3	75%	1	4.8%
Gastroenteritis	3	2	66.7%	1	4.8%
Patients admitted to ICU (from buccal cavity, skin swab, and eye swab)	10	7	70%	2	9.5%
Total	100	54	54%	11	11%

Note: Percentages correlated with number of MDR P. aeruginosa isolates from each type of infection.

Abbreviations: ICU, intensive-care unit; MDR, multidrug-resistant; ESBL, extended-spectrum β-lactamase; MBL, metallo-β-lactamase.

Table 4 Distribution of different groups of carbapenem-resistance genes in phenotypically positive ESBL- and MBL-producing Pseudomonas aeruginosa isolates

	blaCTXM-15 positive isolates	blaIMP	blaVIM	blaGIM	blaSPM
	n (%*)	n (%*)	n (%*)	n (%*)	n (%*)
ESBL^+/MBL^–, n=49	27 (55.1)	0 (0)	7 (14.2%)	3 (6.1)	2(4)
ESBL^–/MBL^+, n=6	0 (0)	6 (100)	2 (33.3)	3 (50)	2 (33.3)
MBL^+/ESBL, n=5	3 (60)	3 (60)	2 (40)	3 (60)	3 (60)

Note: *Percentages were correlated with number of isolates positive for ESBL, MBL, or both.

Abbreviations: ESBL, extended-spectrum β-lactamase; MBL, metallo-β-lactamase; IMP, imipenemase; VIM, Verona integron–encoded MBL; GIM, German imipenemase MBL; SPM, S>o Paulo MBL.

Table 5 Demographic, phenotypic and genotypic features of MBL-producing Pseudomonas aeruginosa

Group	Carbapenem-resistance genes				Sample	Isolate source	Hospital	ESBL production	blaCTXM15	Resistance pattern
	blaIMP	blaVIM	blaGIM	blaSPM
A	+	–	+	–	PA1 PA2 PA8	ICU Wound swab ICU	Minia University	–,+_	–,–	CAZ, CN, AK, PB, MEM CAZ, CEP, TGC, MEM CAZ, CN, CT, CIP, IPM
B	+	+	–	+	PA7	Stool	Minia University	_	_	CAZ, CEP, AK, CT, PB, MEM
C	+	–	–	–	PA9	Wound swab	Minia University	+	+	CAZ, CN, TGC, CIP, IPM
D	+	–	–	+	PA11 PA33	Ear discharge Wound swab	Minia University	–,+	–,+	CAZ, CEP, AK, PB, CIP, IPM, CAZ, CEP, CN, CT, MEM
E	+	–	+	+	PA13	ICU	Minia University	+	+	CAZ, CN, AK, TGC, PB, MEM
F	+	+	–	–	PA16	Stool	Minia University	_	_	CAZ, CEP, AK, TGC, CIP, MEM
G	–	+	+	+	PA19	Wound swab	Minia University	_	_	CAZ, CN, AK, CT, PB, IPM
H	–	+	+	–	PA27	Sputum	Chest Hospital	+	_	CAZ, CEP, CN, AK, TGC, PB, MEM

Notes: A, MBL-producing P. aeruginosa isolates positive for bla_IMP and bla_GIM; B, MBL-producing P. aeruginosa isolates positive for bla_IMP, bla_VIM, and bla_SPM; C, MBL- producing P. aeruginosa isolates positive for bla_IMP; D, MBL-producing P. aeruginosa isolates positive for bla_IMPand bla_SPM; E, MBL-producing P. aeruginosa isolates positive for bla_IMP, bla_GIM, and bla_SPM; F, MBL-producing P. aeruginosa isolates positive for bla_IMP and bla_VIM; G, MBL-producing P. aeruginosa isolates positive for bla_VIM, bla_GIM, and bla_SPM; H, MB-producing P. aeruginosa isolates positive for bla_VIM and bla_GIM.

Abbreviations: ESBL, extended-spectrum β-lactamase; MBL, metallo-β-lactamase; ICU, intensive-care unit; CAZ, Ceftazibime, CN, Gentamicin, AK, Amikacin, PB, ploymxin B, MEM, meropenem, TGC, Tigecycline, CEP, cefeperazone, CT, colistin, CIP, ciprofloxacin, IPM, imipenem; IMP, imipenemase; VIM, Verona integron–encoded MBL; GIM, German imipenemase MBL; SPM, S>o Paulo MBL.