Detection of OXA-51 Carbapenemase Gene in Klebsiella pneumoniae: A Case Report and a New Dimension on Carbapenemase Resistance

Abstract

We investigated the occurence of genes associated with the production of carbapenem hydrolysing carbapenemases in Klebsiella pneumoniae isolates recovered from ICU patient. Antimicrobial susceptibility testing was performed and resistance genes were characterized by PCR amplification and sequencing. The Modified Hodge Test (MHT), MBL E-test, EDTA and aminophenylboronic acid (APBA) combined disk diffusion method, and a disk enzymatic assay were performed for the screening of carbapenemases. MICs of carbapenems were as follows (mg/L) ertapenem 8, meropenem 1, imipenem 0.25 and doripenem 0.5. The isolate demonstrated positive results in the ESBL, EDTA and APBA combined tests, and disk enzymatic assay. PCR and sequencing revealed the presence of bla OXA-51 and bla CTX-M-15 beta-lactamase genes. Plasmids were not transferred to recipient E.coli by conjugation and transformation. In conclusion, we report on the first detection of the OXA-51 harboring K.pneumoniae isolate and co-produced a CTX-M-15 β-lactamase.