ABSTRACT
During a period of 6 years and 5 months (January 1999 to May 2005), 103 extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae isolates, each from an individual patient or site, were collected at Mongi Slim University Hospital Centre, Tunis, Tunisia. The objectives of our work were the characterization of the bla genes encoding ESBLs, the investigation of clonal diversity of strains, and identification of the transmission modes of the resistance genes. We carried out detection by PCR and sequencing of the bla(SHV), bla(CTX-M) and bla(TEM) genes, transferability studies, plasmid replicon typing, and analysis by multilocus sequence typing (MLST) on selected isolates. Forty-seven isolates were found to be producers of CTX-M-type ESBLs, of which 43 were CTX-M-15, two CTX-M-14 and two CTX-M-27. Fifty-eight isolates were producers of SHV-12, and three were producers of SHV-2a. More than one ESBL was detected in seven isolates, as five produced both CTX-M-15 and SHV-12, and two produced both CTX-M-27 and SHV-12. By a PCR-based replicon typing method, the plasmids carrying the bla(SHV-2a) or bla(CTX-M-15) genes were assigned to IncFII or, more rarely, to IncL/M types. Of 12 plasmids carrying the bla(SHV-12) gene, only one could be typed: it was positive for the HI2 replicon. The MLST results showed large genetic background diversity in the SHV-12-producing isolates and dissemination of specific clones of the CTX-M-15-producing isolates within the same ward and among wards, and suggested endemicity with horizontal dissemination of the bla(CTX-M-15) and the bla(SHV-12) genes.
Subject(s)
Bacterial Typing Techniques , Klebsiella Infections/microbiology , Klebsiella pneumoniae/classification , Klebsiella pneumoniae/enzymology , beta-Lactamases/biosynthesis , Cluster Analysis , Gene Transfer, Horizontal , Genotype , Hospitals, University , Humans , Klebsiella pneumoniae/isolation & purification , Molecular Epidemiology , Plasmids , Polymerase Chain Reaction , Polymorphism, Genetic , Sequence Analysis, DNA , Tunisia/epidemiologyABSTRACT
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.
