Outbreak of colistin-resistant carbapenemase-producing Klebsiella pneumoniae in Tunisia.

Objectives: Mechanisms of colistin and carbapenem resistance among a collection of Klebsiella pneumoniae isolates recovered in a university hospital in Tunisia were studied.

Methods: In vitro antimicrobial susceptibility testing, S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), Southern blotting and PCR-based replicon typing (PBRT) were performed. Extended-spectrum β-lactamases (ESBLs), carbapenemases, AmpC-type enzymes and mgrB genes were detected by PCR and sequencing.

Emergence of ST147 Klebsiella pneumoniae Producing OXA-204 Carbapenemase in a University Hospital, Tunisia.

Molecular features of the first carbapenem-resistant Klebsiella pneumoniae isolates (KP1 and KP2) from the University Hospital Tahar Sfar, Tunisia, were investigated. Antimicrobial susceptibility testing, multilocus sequence typing, S1 nuclease pulsed-field gel electrophoresis, Southern blot, and polymerase chain reaction (PCR)-based replicon typing were performed. Extended-spectrum β-lactamases and carbapenemase genes were detected by PCR and sequencing.

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

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.

Occurrence of conjugative IncF-type plasmids harboring the blaCTX-M-15 gene in Enterobacteriaceae isolates from newborns in Tunisia.

Background: CTX-M-15 is the dominant type of extended-spectrum β-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.

Multidrug-resistant Acinetobacter baumannii strains carrying the bla(OxA-23) and the bla(GES-11) genes in a neonatology center in Tunisia.

Multidrug-resistant and difficult-to-treat Acinetobacter baumannii may be responsible for nosocomial infections. The production of carbapenem-hydrolyzing class D β-lactamases (CHDLs) and extended-spectrum β-lactamase (ESBLs) of the GES type possessing a carbapenemase activity has been increasingly reported worldwide in A. baumannii.

Emergence of SHV-12 extended spectrum beta-lactamase among clinical isolates of Enterobacter cloacae in Tunisia.

A collection of seven multidrug-resistant clinical isolates of Enterobacter cloacae with reduced susceptibility to ceftazidime and cefepime recovered from 2009 to 2010 at the University Hospital of Mahdia, Tunisia, was analysed. PCR analysis and sequencing demonstrated that all study isolates harbored SHV-12 β-lactamase that was transferred by conjugation. Characterization of the regions surrounding the bla(SHV-12) showed that this gene was flanked by two IS26 elements.

[Virulence factors in Pseudomonas aeruginosa: mechanisms and modes of regulation].

Pseudomonas aeruginosa is a bacterium responsible for severe nosocomial infections, life-threatening infections in immunocompromised persons, and chronic infections in cystic fibrosis patients. The bacterium's virulence depends on a large number of cell-associated and extracellular factors. The virulence factors play an important pathological role in the colonization, the survival of the bacteria and the invasion of tissues.