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

Emergence and dominance of CTX-M-15 extended spectrum beta-lactamase among Escherichia coli isolates from children

Of forty-seven extended-spectrum cephalosporin-resistant Escherichia coli isolates, collected from children at the Children’s Hospital in 2006 (Tunis, Tunisia), we analyzed 32 isolates that were genotypically different by enterobacterial repetitive intergenic consensus -polymerase chain reaction. For all isolates, the double-disk diffusion test revealed synergy between clavulanate and cefotaxime and/or ceftazidime, suggesting the production of extended-spectrum beta-lactamases. Polymerase chain reaction experiments, performed on plasmid DNA, and sequencing revealed the presence of blaTEM-1B (26 isolates, 81%), blaTEM-34(IRT-6) (3 isolates, 9%), blaSHV-12 (2 isolates, 6%), and blaCTX-M-15 (31 isolates, 97%). Further, the insertion sequence ISEcp1 was found upstream from the blaCTX-M-15 gene in 11 isolates. The bla genes were found alone or in various combinations in a single isolate. blaTEM-1B and blaCTX-M-15 genes were detected in 26 out of the 32 isolates. Three isolates harbored both blaTEM-34(IRT-6) and blaCTX-M-15. blaSHV-12 was identified either alone or with blaCTX-M-15 in a single isolate. Our investigation showed the dominance of CTX-M-type extended-spectrum beta-lactamases, with CTX-M-15 particularly common, and to our best knowledge, this is the first report of the coexistence of CTX-M-15 and IRT-6 in E. coli isolates from children in Tunisia.Fil: Réjiba, Samia. Université Tunis El-Manar; Túnez. Hôpital d’Enfants; TúnezFil: Mercuri, Paola Sandra. Universite de Liege; BélgicaFil: Power, Pablo. Universite de Liege; Bélgica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Kechrid, Amel. Hôpital d’Enfants; Túne