Antibiotic resistance and genotyping of clinical group B Salmonella isolated in Accra, Ghana

Abstract

AIMS: The purpose of this study was to investigate the antibiotic resistance and clonal lineage of serogroup B Salmonella isolated from patients suspected of suffering from enteric fever in Accra, Ghana. METHODS AND RESULTS: Serogroup B Salmonella were isolated from blood (n=28), cerebral spinal fluid (CSF) (n=1), or urine (n=2), and identified based on standard biochemical testing and agglutinating antisera. Isolates were examined for their susceptibility to ampicillin, chloramphenicol, tetracycline and trimethoprim-sulfamethoxazole. Most of the isolates could be classified as multiple-drug resistant. Furthermore, the genetic location of resistance genes was shown to be on conjugative plasmids. Genetic fingerprinting by plasmid profiling, enterobacterial repetitive intergenic consensus (ERIC)-PCR, and repetitive element (REP)-PCR were performed to determine the diversity among the isolates. Plasmid profiling discriminated five unique groupings, while ERIC-PCR and REP-PCR resulted in two and three groupings, respectively. CONCLUSIONS: A high rate of antibiotic resistance was associated with the Salmonella isolates and the genes responsible for the resistance are located on conjugative plasmids. Also, there appears to be minimal diversity associated with the isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: As a result of the increasing antibiotic resistance among bacteria of all genera, surveys to monitor microbial populations are critical to determine the extent of the problem. The inability to treat many infectious diseases with current antibiotic regimens should prompt the medical community to be more prudent with its antibiotic use.