Dissemination of an extended spectrum beta-lactamase producing Klebsiella pneumoniae strains in a Tunisian university hospital center

On a period of four years (january 1999-december 2002), 49 strains (non redundant) of extended spectrum beta-lactamase-producing Klebsiella pneumoniae from 43 hospitalised patients and three strains from the environment hospital were collected at Mongi Slim University Hospital Center. The objectives of our work were to investigate for clonality of strains, to clarify transmission fashions and reservoirs of the infection by reviewing clinical records and typing strains. Antibiotic susceptibility testing, plasmid analysis and Random Amplified Polymorphic DNA (RAPD) have been done. 84% of the patients were hospitalized in the intensive care and pediatric units. Urinary infections and septicaemias were the more frequent infections (74.2%). The 49 isolats have been classified in 13 antibiotypes. The plasmid analysis showed 16 patterns. The RAPD revealed 28 patterns and variation within patterns in five cases. Our results showed a diversity of the strains suggesting endemicity, possible transmission of plasmids and persistence of some clones which circulated between services. The used markers permitted the evaluation of a long-term strategy of prevention requiring a strict observance of hygiene rules and rational use of antibiotics.