Phenotypic and Genotypic Identification of Carbapenemase-producing Klebsiella pneumoniae in Bushehr Province, Iran

Introduction and Objectives: The emergence of carbapenem-resistant pathogens particularly, the increasing prevalence of carbapenemase-producing Klebsiella pneumoniae poses a serious threat to public health worldwide. The aim of this study was to evaluate the prevalence of carbapenemase-producing Klebsiella pneumoniae using phenotypic and genotypic methods. Materials and Methods: A total of 151 non duplicate K. pneumoniae isolates were collected from six hospitals in Bushehr province and confirmed using PCR of malate dehydrogenase (mdh) gene. Antimicrobial susceptibilities were determined by disk diffusion and E-test methods. The modified carbapenem inactivation method (mCIM), EDTA-modified carbapenem inactivation method (eCIM) and OXA-48 Disk Test were used for phenotypic confirmation of carbapenemase production. The resistance genes including blaKPC, blaNDM, blaOXA-48, blaIMP, blaVIM, and blaGES were detected by PCR method. Results: Totally 12 (7.9%) carbapenemase-producing K. pneumoniae isolates were identified. Antibiogram results via disk diffusion revealed colistin (99.4%) as the most effective of all 18 tested antimicrobial agents. Carbapenemase-producing isolates exhibited a range of imipenem MIC values from 4 μg/ml to ≥32μg/ml. The results of molecular detection were in accordance with phenotypic confirmatory tests. PCR results indicated that blaNDM-1 and blaOXA-48 genes were found in 11(91.6%) and 4 (33.3%) carbapenemase-producing isolates respectively. It is notable that the coexistence of blaNDM and blaOXA-48 was seen in 3 (25%) isolates. In addition, blaKPC, blaIMP, blaVIM, and blaGES were not found in our isolates. Conclusion: Our findings highlight the emergence and dissemination of NDM-producing K. pneumoniae and emphasize the need for intensive surveillance and precautions.

کلیدواژه ها:

Klebsiella pneumoniae ، KPC ، NDM-1 ، OXA-48 ، Carbapenemases