Molecular Detection of IMP Carbapenemase-Producing Gram-Negative Bacteria Isolated From Clinical Specimens in Ahvaz, Iran

The emergence and spread of carbapenem-resistant Enterobacteriaceae (CRE), producing acquired carbapenemases, have created a global public health problem. Carbapenems are important therapeutic agents for the treatment of infections due to multidrug-resistant Gram negative bacteria, particularly those carrying genes for AmpC and extended-spectrum and depressed β-lactamases. Early detection of fecal CRE carriers is essential for effective infection control. The aim of this study was to detect IMP carbapenemases by phenotypic combined disk es and pcr of IMP gene in Gram-negative bacteria..
In this study, 600 Enterobacteriaceae clinical isolates were collected and identified by standard biochemical tests. Antimicrobial susceptibility tests were performed using standard disk diffusion method based on guidelines of the Clinical and Laboratory Standards Institute (CLSI). Phenotypic identification of carbapenemases for isolates was done by the combined disk test by ertapenem and imipenem. The carbapenemase blaIMP gene was detected by the Polymerase Chain Reaction (PCR) method..
The results of this study showed that Escherichia coli (59.0 %), Enterobacter species (21.0%), and Klebsiella spp. (10.7%) were the most common clinical isolates among the Enterobacteriaceae. The highest and lowest rates of resistance towards ceftriaxone were 37 and 7.5, respectively. Out of 25 isolates, 4.1% were screened positive by the ertapenem and/or imipenem combined- disk tests. None of these 25 isolates were positive for IMP Gene..
Our results showed high resistance of Enterobacteriaceae isolates to third generation cephalosporin and carbapenem antibiotics. Supervision in antibiogram tests and also prescription of susceptible antibiotics could prevent spread of carbapenem­resistant Enterobacteriaceae and the other of extended spectrum beta Lactamase (ESBL)-producing isolates..