Molecular characterization and antibiotic resistance of Salmonella in children with acute gastroenteritis in Abuja, Nigeria.

INTRODUCTION

In Nigeria, acute gastroenteritis in children under five years of age is a major cause of mortality and morbidity; identification and characterization of microbial agents of acute gastroenteritis, including Salmonella, remains a powerful tool for effective management, surveillance, and control.

METHODOLOGY: Diarrheal stool samples were directly plated onto differential and selective media to isolate Salmonella. Extended-spectrum beta-lactamases were screened using the double disk diffusion technique and by PCR targeting the blaTEM and blaCTX-M genes. Pulsed-field gel electrophoresis (PFGE) was performed usingthe PulseNet Canada Laboratory protocol for molecular subtyping using the restriction enzymes XbaI and BlnI.

RESULTS

The serotypes identified were Salmonella enterica serovar Zanzibar (n = 5), Salmonella Brancaster (n = 3), and one isolate of Salmonella Enteritidis (phage type 1). The following levels of resistance were found among the Salmonella strains: amoxicillin, five strains (55.6%); amoxicillin-clavulanic acid, two strains (22.2%); cephalexin, five strains (55.6%); and cefuroxime, five strains (55.6%). Intermediate resistance was found in five strains (55.6%) only to amoxicillin-clavulanic acid. All isolates were susceptible to nalidixic acid, ciprofloxacin, and ceftriaxone, and no ESBL-producing Salmonella were detected.

CONCLUSIONS

Our findings demonstrated the involvement of three Salmonella serovars in acute gastroenteritis; resistance to penicillins and cephalosporins was common.