Table 3.

Studies that performed genotypic methods to detect genes encoding carbapenemase enzymes

Author (year)	Setting	Population	Samples	Microorganism (no.)	MIC	Method of carbapenemase detection	Resistance to FQ and AG	Resultsb	Weak points	Strength points	Found carbapenemase genesa
Sharikhani et al (2017)45	Four hospitals in Qom	General inpatients (mostly ICU)	Different sites	Acinetobacter baumannii (108)	–	• DD • PCR	CIP and AMK 93% GEN 81% LVX 91% TOB 47%	• 89% isolates were non-susceptible to IPM and MEM • Among carbapenem non-susceptible isolates, 82%, 55%, 22%, and 14% isolates had blaOXA-23, blaOXA-58, blaOXA-40, and blaOXA-143 genes, respectively	–	• First report of blaOXA-143 in Iran • Multicenter study	blaOXA-51 blaOXA-23 blaOXA-40 blaOXA-58 blaOXA-143
Mohammadi et al (2017)46	Two hospitals in Tehran	General inpatients	Burn wound and trachea	A. baumannii (103)	–	• DD • PCR	–	• About 90% of isolates were resistant to carbapenem • blaOXA-23, blaOXA-24, blaOXA-58, blaTEM, and blaPER genes were detected in 90%, 38%, 1%, 60%, and 18.5% of all isolates, respectively • Significant relationship between the presence of blaOXA-24 and resistance to IPM (not MEM) • All strainshad biofilm producing ability		• Ability of biofilm formation was assessed • Correlation between presence of genes and resistance to antibiotics was defined	blaOXA-23, blaOXA-24, blaOXA-58, blaTEM, blaPER
Bahador et al (2015)44	One hospital in Tehran	Burn patients	Not defined (probably burn wounds)	A. baumanii (62)	✓	• DD • PCR • Clonal typing	Not reported specifically	• According to MIC values, 61% were resistant to IPM • From all strains, 39 had bla OXA-23 (33 were susceptible to IPM), 9 had blaOXA-58.genes • Existence of two genes (in 1.6%–19.3% of strains) was correlated with MIC more than 32 mcg/mL for IPM	• Resistance to each antibiotic was not reported specifically • Small sample size	• MIC values of IPM, tigecycline, and colistin were reported • ISAba gene was assessed	blaoxa-51 blaoxa-23 blaoxa-24 blaoxa-40’ blaoxa-143
Kooti et al (2015)47	Four hospitals in Shiraz	General inpatients	Different sites	A. baumannii (200)	–	• DD • PCR	GEN 84.5% AMK 86.5% CIP and LVX 99.5%	• About 99% of isolates were resistant to IPM and MEM • 40% had blaOXA-23, 7% had blaOXA-24, 0.5% had blaOXA-58 • Two bla genes were detected in 4.5% of strains • The correlation between presence of genes and source of samples was not significant	–	Multicenter study	blaOXA-23 blaOXA_24 blaOXA-58
Azizi et al (2015)43	Two hospitals in Kerman	ICU patients	Different sites	A. baumannii (65 MDR strains from 266)	✓	• DD • PCR	CIP 100% AMK 78.5% TOB 93%	• MIC values for IPM and MEM for 76% of strains were >256 mcg/mL • blaoxa-23 was found in all isolates including sensitive and resistant isolates • Presence of blaOXA 24/40 (29 strains) associated with higher MIC	–	–	blaoxa-51, blaoxa-23, blaoxa-24/40
Mahdian et al (2015)48	One hospital in Tehran (Motahari)	Burn patients	Burn wounds, blood, urine	A. baumanii (37)	–	• DD • PCR • Clonal typing	CIP 100% GEN 94.6%	• 81% of strains were resistant to carbapenem  ◦ All resistant isolates had at least one blaOXA-23 and/or blaOXA-24 and about half of them had both genes	• Small sample size • Few antibiotics were tested	• MIC values for colistin and polymyxin B were reported • ISAba genes were assessed	blaOXA-23, blaOXA-24, blaTEM, blaPER
Farsiani et al (2015)49	One hospital in Mashhad	General inpatients and ICU patients	Different sites	A. baumannii (36)	✓	• DD • PCR • Clonal typing	CIP 97%	• 97% of strains were resistant to carbapenems • MIC values of resistant isolates were >32 • blaOXA-51 and blaOXA-23 were detected in all isolates • From all isolates, blaOXA-24, blaTEM, blaADC, and blaVIM genes were found in 23, 34, 22, and 23 strains, respectively • ISAba1 was detected in 97% of isolates of A. baumannii	• Small sample size	• ISAba genes and tet genes (related to efflux pump) were analyzed	blaOXA-51, blaOXA-23 blaOXA-24, blaTEM, blaADC blaVIM adeB ISAba1 tetA, tetB
Nasrolahei et al (2014)50	Two hospitals in Tehran and Sari	ICU and burn patients	Trachea and burn wounds	A. baumannii (100)	–	• DD • PCR	STP 90% GEN 83% TOB 83% KAN 80%	• Resistance rate to IPM and MEM was about 70% • 67% of strain carried blaoxa-23 gene	• FQ are not tested	• Multicenter study	blaoxa-23
Safari et al (2014)51	Three hospitals in Hamadan	ICU patients	Different sites	Pseudomonas aeruginosa (100)	✓	• DD • PCR	AMK 19% GEN 28% TOB 27% LVX 28% CIP 38%	• Resistance rate to carbapenems was about 20% • According to MIC values, 24% of isolates were carbapenem-resistant • Four isolates had blaIMP		–	blaIMP
Bahador et al (2014)52	Two hospitals in Tehran	ICU patients	Different sites	A. baumannii (100)	✓	• DD • Clonal typing	c	• Resistance rates were compared among years 2006 and 2011, according to MIC cutoffs • In year 2006, resistance rate to IPM was 30% with MIC ≤4–64 mcg/mL. In year 2011 it was 48% and MIC values were ≤4 to ≥256 mcg/mL • Genotypes I and F were the most frequent genotypes in years 2006 and 2011, respectively		• Range of MIC values for each antibiotic was reported	–
Karmostaji et al (2013)53	Two hospitals in Tehran	General inpatients (mostly ICU)	Different sites	Acinetobacter spp. (131)	–	• DD • PCR	CIP 95% GEN 77% AMK 54%	• Resistance rate to IPM and MEM were 67% and 84%, respectively • 107, 17, and 1 of the resistant isolates carried blaOXA-23, blaOXA-24, and blaOXA-58, respectively. From these strains, seven strains had both blaOXA-23 and blaOXA-24	–	–	blaoxa-51 blaoxa-23 blaoxa-24 blaoxa-58
Shoja et al (2013)54	Two hospitals in Ahvaz	ICU patients	Trachea	A. baumannii (206)	–	• DD • PCR	GEN 83%, TOB 78%, AMK 88%, CIP 96%,	• Resistance rate to IPM and MEM was 96% • blaOXA-23 and blaOXA-24 was found in 85% and 8% of all strains, respectively.	–	–	blaOXA-23 blaOXA-24
Sohrabi et al (2012)55	One hospital in Tabriz	General inpatients	Different sites	A. baumanii (100)		• DD • PCR	CIP and GEN 86% LVX 84% AMK 81%	• 62% of isolates were resistant to carbapenems • Out of 62 resistant isolates, 55 carried blaOXA-23, 1 carried blaOXA-40, and 2 isolates had blaOXA-58 genes	–	–	blaOXA-23 blaOXA-58 blaOXA-40
Sepehriseresht et al (2012)56	One hospital in Tehran (Motahari)	Burn patients	Burn wounds	P. aeruginosa (483)	–	• DD • PCR	–	• 56% of isolates were resistant to IPM, although 13% intermediate resistance should be considered • Among resistant isolates, 61 and 33 isolates had blaVIM and blaIPM genes, 23 strains had 2 resistant genes	• Origin of blaIPM is not clear	–	blaVIM blaIPM
Forozesh Fard et al (2012)57	One hospital in Isfahan	CF patients	Sputum	P. aeruginosa (11)	–	• DD • PCR	CIP 0% TOB 45.4%	• None of the isolates was resistant to IPM. None was positive for blaVIM gene	• Very small sample size • Few antibiotics were tested	–	–
Peymani et al (2012)58	One hospital in Tabriz	General inpatients	Different sites	A. baumannii (68)	–	• PCR • Clonal typing	–	• All IPM-resistant isolates were chosen for study • 44% of isolates were from tracheal samples • All were positive for blaOXA-23, and ISAba1 was present upstream of all blaOXA-23 genes	–	–	blaOXA-23
Asadollahi et al (2012)59	One teaching hospital in Tehran	ICU burn patients	Burn wounds	A. baumannii (23)	✓	• DD • PCR	CIP 100% GEN 30% AMK 47%	• Resistance rate to IPM was 48% • Range of MIC values for IPM was 0.004–32 mcg/mL • From all strains, blaPER and blaTEM genes were present in 52% and 43% of isolates, respectively. 21% and 17% of isolates had blaOXA- and blaOXA24 genes, respectively	Small sample size	• MIC values were reported for each antibiotic • CarO and tet genes were assessed	blaTEM blaPER blaOXA-23 blaOXA-24 blaSHV
Taherikalani et al (2009)42	Six hospitals in Tehran	General impatients	Different sites	A. baumannii (80)	✓	• DD • PCR • Clonal typing	–	• 52% of isolates were carbapenem resistant • MIC50 range for carbapenem was 0.12–256 mcg/mL • Seven isolates that had MIC =256 mcg/mL had more than two blaOXA genes • From all strains blaOXA-23 in 25%, blaOXA-58 in 21%, and blaOXA-24 in 15% genes were detected • Coexistence of multiple genes was observed	• Number of tested antibiotics were few	• Multicenter study	blaoxa-23 blaoxa-24 blaoxa-58
Feizabadi et al (2008)60	One hospital in Tehran	General inpatients	Different sites	Acinetobacter spp. (A. baumannii =108 and other Acinetobacter =20, total =128)	✓	• DD • PCR	CIP 81% LVX 74% AMK 61% NTL 86% TOB 79% GEN 81%	• About 50% of strains were resistant to carbapenems • MIC values for carbapenem-resistant species were ≥64 to ≥256 mcg/mL • For details of isolated genes, refer to original article			blaoxa-23 blaoxa-24 blaoxa-51 blaoxa-58
Taherikalani et al (2008)61	Two hospitals in Tehran	Burn patients	Burn wounds	A. baumannii (38)	–	• DD • PCR	Resistance AMK 71% TOB 90% NTL 90% LVX 81% CIP 85%	• Resistance rate to carbapenem was about 60% • Half of the carbapenemresistant strains had at least two blaOXA genes	• Small sample size • MIC values were not determined		blaoxa-23 blaoxa-24 blaoxa-51 blaoxa-58

Notes:

^aResults about bla_OXA-51 were not provided because this gene has no correlation with occurrence of resistance, unless it has ISAba genes in its upstream.

^bResistance rates were according to the results of disk diffusion test.

^cFor complete information about the resistance to AG and FQ, please refer to the original reference.

Abbreviations: AG, aminoglycoside; AMK, amikacin; CIP, ciprofloxacin; DD, disk diffusion; FQ, fluoroquinolones; GEN, gentamicin; ICU, intensive care unit; IPM, imipenem; KAN, kanamycin; LVX, levofloxacin; MEM, meropenem; MIC, minimum inhibitory concentration; NAL, nalidixic acid; PCR, polymerase chain reaction; STP, streptomycin; TOB, tobramycin; NTL, netilmicin.