High Prevalence of blaNDM Among Carbapenem Non‑Susceptible Klebsiella pneumoniae in a Tunisian Hospital First Report of blaNDM‑9, blaKPC‑20, and blaKPC‑26 Genes

peer reviewedFifty-four carbapenem non-susceptible Klebsiella pneumoniae (CNSKP) isolates were collected from a Tunisian hospital over a period of 13 consecutive months. Carbapenemase production and the prevalence of carbapenemase-encoding genes were investigated using combined-disk test (CDT), modified Carba NP (mCarba NP) test, and UV-spectrophotometry method complemented by PCR experiments and sequencing. Carbapenemase production was detected by the mCarba NP test and CDT in 92.59% and 96.29% of the 54 CNSKP isolates, respectively; while imipenem hydrolysis was detected using UV-spectrophotometry in the crude extracts of 44 isolates. blaNDM, blaOXA-48-like , and blaKPC carbapenemase-encoding genes were found in 48, 31, and 22 isolates, respectively. Remarkably, blaNDM-9, blaKPC-20 , and blaKPC-26 genes were reported. The co-occurrence of carbapenemase-encoding genes in a single isolate was detected in 62.96% of the isolates. The analysis of clonal relationships between the isolates by pulsed field gel electrophoresis revealed that the majority of them were geneti-cally unrelated. Our investigation provides molecular data on enzymatic mechanism of carbapenem non-susceptibility among 54 CNSKP showing the dominance of blaNDM, and comprises the first identification of blaNDM-9, blaKPC-20 , and blaKPC-26 genes in a Tunisia hospital