Characterization of sulphonamide resistance genes and class 1 integron gene cassettes in Enterobacteriaceae, Central African Republic (CAR)

Abstract

The aim of this study was to characterize genes encoding sulphonamide resistance and gene cassettes associated with class 1 integrons in trimethoprim-sulphamethoxazole resistant Enterobacteriaceae recovered from Bangui, Central African Republic (CAR). We studied 78 clinical Enterobacteriaceae isolates, including 16 extended-spectrum β-lactamases producers, 10 Salmonella and 9 Shigella, resistant to trimethoprim-sulphamethoxazole as assessed by the disc diffusion method. PCR was used to test for sul1 and sul2 genes. Class 1 integron resistance gene cassettes were characterized by directly sequencing PCR products obtained with primers recognising 5′ and 3′ conserved regions. The sul1 gene was found in 67 isolates, the sul2 gene in 72 isolates and both genes in 62 isolates, while the int1 gene was found in 74 isolates. The most prevalent dfr genes were dfrA7 (49%), dfrA1 (17%) and dfrA2d (13%). These results illustrate the wide distribution of sulphonamide and trimethoprim resistance genes among Enterobacteriaceae in Bangui (CAR).