Distribution and Molecular Characterization of Resistance Gene Cassettes Containing Class 1 Integrons in Multi-Drug Resistant (MDR) Clinical Isolates of Pseudomonas aeruginosa

Figures & data

Table 1 The Comparison of Antibiotic Resistance Profile Between the Integron Positive and Negative Clinical Isolates of Pseudomonas aeruginosa

Antibiotics	Total (n=100)			Integron Positive (n=42)			Integron Negative (n=58)			P-value
	R	I	S	R	I	S	R	I	S
AK	28	13	59	19	5	18	9	8	41	0.0042
GN	41	5	54	26	2	14	15	3	40	0.0012
TN	39	1	60	25	0	17	14	1	43	0.0014
CIP	41	3	56	25	0	17	16	3	39	0.0034
LEV	43	3	54	26	1	15	17	2	39	0.0050
ATM	39	33	28	25	10	7	14	6	21	0.0039
PTZ	12	11	77	10	5	27	2	4	50	0.0052
CPM	32	5	63	21	1	20	11	4	43	0.0040
CAZ	27	2	71	16	1	25	11	1	46	0.0955
PRL	26	21	53	17	12	13	9	9	40	0.0007
DOR	28	11	61	22	3	17	6	8	44	0.0001
IMI	31	8	61	18	5	19	13	3	42	0.0222
MEM	37	5	58	26	0	16	11	5	42	0.0001

Note: All results in this table about the rate of resistance or susceptibility of the isolates are based on the percent.

Abbreviations: R, resistant; I, intermediate resistant; S, susceptible; AK, amikacin; GN, gentamicin; TN, tobramycin; CIP, ciprofloxacin; LEV, levofloxacin; ATM, aztreonam; PTZ, piperacillin-tazobactam; CPM, cefepime; CAZ, ceftazidime; PRL, piperacillin; DOR, doripenem; IMI, imipenem; MEM, meropenem.

Table 2 The Comparison of Resistance Percent Rates Against 13 Tested Antibiotics Among the MDR and Non-MDR Isolates of Pseudomonas aeruginosa

Antibiotics	MDR Isolates (n=41)			Non MDR Isolates (n=59)			P-value
	R	I	S	R	I	S
AK	27	6	8	1	7	51	< 0.0001
GN	39	1	1	2	4	53	< 0.0001
TN	38	0	3	1	1	57	< 0.0001
CIP	38	1	2	3	2	54	< 0.0001
LEV	38	0	3	5	3	51	< 0.0001
ATM	38	3	0	1	30	28	< 0.0001
PTZ	12	11	18	0	0	59	< 0.0001
CPM	32	3	6	0	2	57	< 0.0001
CAZ	27	2	12	0	0	59	< 0.0001
PRL	26	13	2	0	8	51	< 0.0001
DOR	25	6	10	3	5	51	< 0.0001
IMI	24	4	13	7	4	48	< 0.0001
MEM	30	3	8	7	2	50	< 0.0001

Abbreviations: R, resistant; I, intermediate resistant; S, susceptible; MDR, multi-drug resistance; AK, amikacin; GN, gentamicin; TN, tobramycin; CIP, ciprofloxacin; LEV, levofloxacin; ATM, aztreonam; PTZ, piperacillin-tazobactam; CPM, cefepime; CAZ, ceftazidime; PRL, piperacillin; DOR, doripenem; IMI, imipenem; MEM, meropenem.

Table 3 The Prevalence of Different Resistance Gene Cassette Arrays in the Clinical Isolates of Pseudomonas aeruginosa and Their Correlation with the Resistance Towards Tested Antibiotics

Length of IVRs (kb)	Gene Cassettes	No. of Isolates	(No.) of Isolates Which Were Resistant to	No. of MDR Isolates
0.6	Hypothetical gene cassette	1	AK (1), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (1), CPM (1), CAZ (0), PRL (1), DOR (1), IMI (1), MEM (1)	1
0.75	aadB	7	AK (2), GM (3), TN (3), CIP (3), LEV (3), ATM (3), PTZ (1), CPM (3), CAZ (3), PRL (2), DOR (2), IMI (2), MEM (4)	3
1.3	aadA6-orfD	7	AK (1), GM (2), TN (2), CIP (1), LEV (1), ATM (1), PTZ (0), CPM (2), CAZ (2), PRL (1), DOR (2), IMI (1), MEM (2)	2
1.7	aacA4-blaOXA-10	1	AK (0),GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (0), CPM (1), CAZ (1), PRL (1), DOR (0), IMI (0), MEM (0)	1
2.3	aadB-aacA4-blaOXA-10	1	AK (0), GM (0), TN (0), CIP (0), LEV (0), ATM (1), PTZ (0), CPM (0), CAZ (1), PRL (0), DOR (1), IMI (0), MEM (1)	1
2.5	blaOXA-10-aacA4-VIM1	3	AK (2), GM (2), TN (2), CIP (2), LEV (2), ATM (2), PTZ (1), CPM (2), CAZ (0), PRL (0), DOR (2), IMI (1), MEM (2)	2
3.5	aacA5-aadA1-cmlA5	2	AK (0), GM (2), TN (2), CIP (1), LEV (2), ATM (1), PTZ (0), CPM (0), CAZ (0), PRL (0), DOR (1), IMI (1), MEM (1)	1
0.6 + 1.7	Hypothetical gene cassette + aacA4-blaOXA-10	1	AK (1), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (0), CPM (1), CAZ (1), PRL (0), DOR (1), IMI (1), MEM (1)	1
0.75 + 1.3	aadB + aadA6-orfD	1	AK (0), GM (0), TN (0), CIP (0), LEV (0), ATM (0), PTZ (0), CPM (0), CAZ (0), PRL (0), DOR (0), IMI (0), MEM (0)	0
0.75 + 1.7	aadB + aacA4-blaOXA-10	2	AK (2), GM (2), TN (1), CIP (2), LEV (2), ATM (2), PTZ (0), CPM (1), CAZ (1), PRL (0), DOR (1), IMI (2), MEM (2)	2
0.75 + 2.0	aadB + blaOXA-31-aadA2	1	AK (0), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (0), CPM (1), CAZ (1), PRL (1), DOR (0), IMI (0), MEM (0)	1
0.75 + 2.3	aadB + aadB-aacA4-blaOXA-10	3	AK (3), GM (3), TN (3), CIP (3), LEV (3), ATM (3), PTZ (2), CPM (2), CAZ (1), PRL (3), DOR (3), IMI (3), MEM (3)	3
1.3 + 1.5	aadA6-orfD + aacA4-catB10	1	AK (0), GM (0), TN (0), CIP (0), LEV (0), ATM (0), PTZ (0), CPM (0), CAZ (0), PRL (0), DOR (1), IMI (1), MEM (1)	0
1.3 + 1.7	aadA6-orfD + aacA4-blaOXA-10	1	AK (1), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (1), CPM (1), CAZ (1), PRL (1), DOR (1), IMI (1), MEM (1)	1
1.3 + 2.3	aadA6-orfD + aadB-aacA4-blaOXA-10	1	AK (0), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (0), CPM (0), CAZ (0), PRL (1), DOR (1), IMI (1), MEM (1)	1
1.5 + 3.0	aacA4-catB10 + aac(3)-Ic-aacA5-cmlA5	1	AK (1), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (1), CPM (1), CAZ (0), PRL (1), DOR (1), IMI (0), MEM (1)	1
2.0 + 3.5	blaOXA-31-aadA2 + aacA5-aadA1-cmlA5	1	AK (0), GM (0), TN (0), CIP (1), LEV (1), ATM (0), PTZ (0), CPM (0), CAZ (0), PRL (0), DOR (0), IMI (0), MEM (0)	0
0.75 + 1.3 + 1.5	aadB + aadA6-orfD + aacA4-catB10	1	AK (1), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (0), CPM (1), CAZ (1), PRL (1), DOR (0), IMI (0), MEM (1)	1
0.75 + 1.3 + 1.7	aadB + aadA6-orfD + aacA4-blaOXA-10	1	AK (0), GM (0), TN (0), CIP (0), LEV (0), ATM (0), PTZ (0), CPM (0), CAZ (0), PRL (0), DOR (1), IMI (1), MEM (1)	0
0.75 + 1.3 + 2.5	aadB + aadA6-orfD + blaOXA-10-aacA4-VIM-1	2	AK (1), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (0), CPM (1), CAZ (1), PRL (1), DOR (0), IMI (0), MEM (1)	1
0.75 + 1.7 + 2.3	aadB + aacA4-blaOXA-10 + aadB-aacA4-blaOXA-10	2	AK (2), GM (2), TN (2), CIP (2), LEV (2), ATM (2), PTZ (2), CPM (2), CAZ (2), PRL (2), DOR (2), IMI (2), MEM (2)	2
1.7 + 2.3 + 3.0	aacA4-blaOXA-10 + aadB-aacA4-blaOXA-10 + aac(3)-Ic-aacA5-cmlA5	1	AK (1), GM (1), TN (1), CIP (1), LEV (1), ATM (1), PTZ (1), CPM (1), CAZ (0), PRL (1), DOR (1), IMI (0), MEM (1)	1
Total	69 gene cassettes	42		26

Abbreviations: VR, variable regions; MDR, multi-drug resistance, AK, amikacin; GN, gentamicin; TN, tobramycin; CIP, ciprofloxacin; LEV, levofloxacin; ATM, aztreonam; PTZ, piperacillin-tazobactam; CPM, cefepime; CAZ, ceftazidime; PRL, piperacillin; DOR, doripenem; IMI, imipenem; MEM, meropenem.

Table 4 Prevalence of MDR and Integron Positive Pseudomonas aeruginosa Clinical Isolates Based on the Source of Isolation

Source of Isolates	No. (%) of
	Total Isolates	MDR Isolates	Integron Positive Isolates
Sputum	37 (37)	11 (29.72)	16 (43.24)
Urine	26 (26)	7 (26.92)	10 (38.46)
Wound	20 (20)	13 (65)	10 (50)
Catheter	8 (8)	7 (87.5)	4 (50)
Blood	5 (5)	2 (40)	2 (40)
Others	4 (4)	1 (25)	0 (0)

Figure 1 The number of integron positive and MDR Pseudomonas aeruginosa clinical isolates according to the hospital sources.

Notes: Hospital 1, Zare (burn center); Hospital 2, Razi (infectious center); Hospital 3, BuAli Sina (pediatric center); Hospital 4, Fatemeh Zahra (heart center); Hospital 5, Imam Khomeini (infectious center).

Figure 2 The size and structure of resistance gene cassettes between two conserved ends (5′CS and 3′CS) of the class 1 integrons detected in the clinical isolates of Pseudomonas aeruginosa.