RESUMO
BACKGROUND: CTX-M-15 is the dominant type of extended-spectrum ß-lactamase in clinical isolates. This enzyme constitutes the most widespread enzymes in Tunisia. In this study, we were interested to understand the causes of the evolutionary success of CTX-M-15 in a Tunisian university hospital. METHODS: A total of of 72 cefotaxime-resistant Enterobacteriaceae were isolated from newborn patients at the hospital Taher sfar Mahdia in Tunisia and characterized their genetic support by means of molecular techniques. RESULTS: Isolates were clustered into various clonal groups, although most isolates belonged to sequence types ST39 (Klebsiella pneumoniae) and ST131 (Escherichia coli). F replicons (FIA, FIB, and FII) were the most frequently detected replicon types in our collection (91.66%). CONCLUSION: This is the first report of QnrB- and CTX-M-15-encoding large IncF-type conjugative plasmids in Tunisia.