Traditional and Molecular Gene Detection (blaIMP-1 and blaIMP) of multi-drug resistant Acinetobacter baumannii

Document Type : Original Article

Authors

1 Urology and Nephrology Center, Mansoura University, Mansoura, Egypt

2 Botany and Microbiology Department, Faculty of Science, Damietta University, Egypt

Abstract

Acinetobacter bacteria are widely resistant to β-lactam antibiotics in. The formation of carbapenemases such metallo—β lactamases (MBLs), which hydrolyze a variety of β-lactams including penicillin, cephalosporins, and carbapenems, is one of the primary causes of resistance in Acinetobacter baumannii. MBL-producing carbapenem-resistant strains have been detected all over the world in recent years, and at a rising pace. The goal of this study is to compare phenotypic and genotypic methods for identifying MBL producers in carbapenem-resistant Acinetobacter baumannii utilizing PCR technique as the gold standard investigation. Fifty-two A. baumannii isolates were chosen for this study according to imipenem (IMP) resistance (MIC >16 µg/ml). Phenotypic expression of MBL was detected applying Modified Hodge test (MHT) and CDDT (Combine Disk Diffusion Test). Genotypic expressions of blaIMP-1 and blaIMP genes were detected by PCR for all metallo β -lactamase producing A. baumannii. Forty nine out of 52 isolates (94.2%) of A. baumannii were carbapenemase producers by MHT while forty-seven (90.4. %) of isolates were MBL producers by CDDT Test. Thirty-nine (75%) A. baumannii of 52 presumptive MBL producer isolates (with isolates were negative for MBL producer in phenotypic technique applied on control isolates) were positive for blaIMP-1 gene by PCR, while fifteen (28.8%) A. baumannii were positive for blaIMP gene by PCR. The co-occurrence of blaIMP-1 and blaIMP genes in 23% (12/52) of cases. Isolates of A. baumannii detected as metallo beta-lactamase (MBL) producers using Modified Hodge test and Combine Disk Diffusion Test, must be confirmed by applying genotypic method.

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