Investigation of the clonal dissemination of Klebsiella pneumoniae isolates producing extended-spectrum beta-lactamases in a neonatal ward, Sousse, Tunisia.

Abstract

This study was designed to investigate the spread of extended-spectrum beta-lactamase producing Klebsiella pneumoniae (ESBL-Kp) strains in Sousse hospital, during 7-month period by using phenotypic and genotypic markers. A total of 57 clinical isolates of ESBL-Kp, 22 strains recovered from seriously infected neonates and 35 strains recovered from colonized neonates and hospitalized in the neonatal ward of Sousse hospital, Tunisia, was subjected to 99 carbon source utilization tests, ribotyping and pulse-field gel electrophoresis (PFGE) profiles of total genomic DNA. Biotyping, ribotyping and PFGE typing showed that four different clones circulated in the neonatal ward between January and July 1997 and suggested that the epidemic strain belonged to the same biotype, ribotype and PFGE pattern, and was represented by 18 isolates from infected neonates and 28 isolates from colonized neonates. Biotyping, ribotyping and PFGE typing appeared to be reliable methods for distinguishing K. pneumoniae strains. Biotyping, which has the advantage of simplicity and rapidity, may be used as a first screening method.