Detection of extended-spectrum beta-lactamase and scarbapenemase-producing Enterobacteriaceae in Tunisia

Abstract

The emergence of dramatic urinary tract infections (UTIs) caused by the members of the Enterobacteriales is an important public health problem in the community as well as in Tunisian hospitals. This study aims to investigate the prevalence of extended-spectrum β-lactamase (ESBL) and carbapenemase-producing uropathogenic isolates of Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae). Based on decreased susceptibility to β-lactams antibiotics and analyzed for the presence of ESBL and carbapenemase genes by Real Time- polymerase chain reaction (RT-PCR), 56 uropathogenic isolates of E. coli (n = 36) and K. pneumoniae (n = 20) were confirmed positive for ESBLs. The CTX-M-type β-lactamases were mostly detected in E. coli isolates (21 strains, 58.33% [95% CI 38.09% - 72.06%]) followed by blaSHV-like (18 strains, 50% [95% CI 32.92% - 67.07%]), blaTEM-like and blaCMY-2-like simultaneously (15 strains, 41.67% [95% CI 25.51% - 59.24%]). Furthermore, the RT-PCR system on the K. pneumoniae strains demonstrated that blaSHV-12-like was the most predominant (16 strains, 80% [95% CI 56.33% - 94.26%]) followed by blaTEM-like (14 strains, 70% [95% CI 45.72% - 88.10%]), blaCTX-M belonging to groups 9 and 1 (11 strains, 55% [95% CI 31.52% - 76.94%]) and finally blaCMY-2-like (10 strains, 50% [95% CI 27.19% - 72.80%]). In addition, E. coli and K. pneumoniae strains harbored a carbapenemase gene blaOXA-48-like with 22.2% [95% CI 10.11% - 39.15%]; 20% [95% CI 12.83% - 43.66%], respectively. Our results confirm the need to monitor the resistance to extended-spectrum β-lactams and to carbapenems among enterobacteria in Tunisia.