Genotypic detection of extended spectrum beta lactamases from selected bacterial isolates in the Specialist Hospital Sokoto, Nigeria

Abstract

There are numerous reported cases of extended spectrum beta lactamases (ESBLs) producing Enterobacteriaceae in Nigeria, with little effort done on the molecular detection. Epidemiological studies around the world have investigated the prevalence of ESBL-producing enterobacteriaceae and they have seen multiple mechanisms of drug-resistance. Our study was designed to detect ESBLs genes such as CTX-M, SHV, and TEM using PCR from clinical isolates in a tertiary hospital in Sokoto metropolis. Clinical isolates from the Microbiology laboratory of the tertiary hospital was collected for 3 months. These isolates were identified using standard microbiological methods. They were tested against 8 antibiotics using the modified Kirby Bauer disc diffusion method. Multidrug resistant isolates were screened for ESBL production, and further confirmed by the Double Disc Synergy Test (DDST). Genotypic confirmation was carried out using multiplex Polymerase Chain Reaction (PCR). A total of 47 isolates made up of 21 E. coli (44.6%), 13 Klebsiella spp (27.6%), 7 Salmonella spp (14.9%), 5 Proteus mirabilis (10.6%), and 1 Enterobacter spp (2.1%) were obtained from urine, stool, and wound swab. Out of the 47 isolates, (45) 95.7% were multidrug resistant. Twenty-five (53.2%) were potential ESBL producers, while only 5 (20.0%) were confirmed phenotypically using a DDST. PCR results revealed 4 out of 5 of the isolates were possessing ESBL genes. It also revealed that 3 isolates co-produce TEM and SHV at 403bp and 293bp respectively. Only 1 isolate produced CTX-M gene at 569bp. The prevalence of ESBL production in the Gram negative enterobacteriaceae in our study did not indicate a high prevalence as reported by some studies in Sokoto and Northwest Nigeria.

Keywords: Molecular detection, ESBLs, Clinical isolates, PCR