Dissemination of multidrug-resistant blaCTX-M-15/IncFIIk plasmids in Klebsiella pneumoniae isolates from hospital- and community-acquired human infections in Tunisia

• This study characterized CTX-M-15 plasmids in K. pneumoniae in Tunisia.
• All K. pneumoniae isolates produced CTX-M-15.
• The blaCTX-M-15 gene was mostly carried on IncFIIk plasmids.
• Identical clones were found among diverse wards at hospital.

This study investigated the molecular features of extended-spectrum β-lactamase (ESBL)–producing Klebsiella pneumoniae from hospital- and community-acquired (HA/CA) infections in the region of Mahdia, Tunisia. Among 336 K. pneumoniae isolates recovered from both clinical contexts between July 2009 and December 2011, 49 and 15 were ESBL producers and originated from clinical and community sources, respectively. All isolates produced the CTX-M-15 enzyme. As shown by Southern blot on S1 nuclease treatment followed by pulsed-field gel electrophoresis (PFGE) gels, the blaCTX-M-15 gene was carried on IncFII (n = 4), IncFIIk (n = 25), IncL/M (n = 4), IncK (n = 1), or untypeable (n = 15) plasmids in HA isolates. In CA isolates, the blaCTX-M-15 gene was carried on IncFIIk (n = 6), IncFII (n = 1), IncHI1 (n = 1), or untypeable (n = 7) plasmids. In all, 23 and 11 PFGE types were found among the HA and CA isolates. Multilocus sequence typing on representative isolates shows diverse sequence types (STs), such as ST307, ST101, ST39, ST4, ST140, ST15, and ST307 in HA isolates and ST101, ST664, and ST323 in CA isolates. This study is the first comprehensive report of ESBL plasmids in K. pneumoniae from HA and CA infections in Tunisia.