Antimicrobial susceptibility profile of class D Oxa B-lactamases producing bacteria in Kano state, Nigeria

Abstract

This study was carried out to determine the antibiotic susceptibility profile of Gram negative bacteria obtained from three different hospitals for class D Oxa β-lactamases in Kano metropolis. The clinical isolates include: Escherichia coli, Klebsiella y pneumoniae, Pseudomonas aeruginosa, Proteus sp and Salmonella spp. A total of 500 clinical isolates were screened phenotyphically using double discs synergy test. Confirmatory tests were performed among the suspeced isolates according to the Clinical and Laboratory Standard Institutes guidelines (CLSI). A total of 13 antibiotic discs were used for sensitivity test including: Amoxicillin/clavulanic acid, ceffazidime, cefepime, cepatozime, cefuruxime, imipenem, meropenem, ciprofloxacin, genetamicin, levoflaxacin, nitrofuranton, tigercyline and ofloxacin. Nine antibiotic discs were used on lactose fermenters and seven antibiotics were used on non–lactose fermenters. The result of the prevalence of class D oxa β lactamases producing bacteria among the clinical isolates revealed that, 26.40% of the clinical isolates were confirmed positive for class D oxa Beta lactamases production with the highest prevalence in E. coli (37.88%) and absent in K. oxytoca. The isolates producing this enzyme were sourced mainly from urine (55.17%) or wound swabs (26.44%). The antibiotic susceptibility profile using class D blaOxa showed that E. coli has overall resistance to clavulanic acid and third generation cephalosporins, with high susceptibility profile to tigercycline. (52.0%) and nitrofuranton (49.00%). K. pneumoniae has the highest susceptibility with tigercyclin and Nitrofuranton (56.7% and 56.4% respectively). The most active agents against non–lactose fermenters were meropenem, tigercycline and levofloxacin. The data highlighted the widespread of antibiotic resistance associated with bla OXA among the Gram –negative bacterial isolates in hospitals from Kano metropolis. The attention of the authorities and healthcare sectors is needed urgently towards the rising spate and widespread resistance due to class D oxa βlactamases so as to device a method to curb this threatening trend.

Key words: Antibiotic susceptibility, resistance, lactose fermenters, non–lactose fermenters.