A 5-year epidemiological study of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae isolates in a medium- and long-stay neurological unit

Thirty-eight different strains of extended-spectrum beta-lactamase (ESBL)-p roducing Klebsiella pneumoniae (ESBL Kp), isolated from urine and pus sampl es of 38 patients hospitalized in a medium- and long-stay neurology departm ent between 1 January 1992 and 31 December 1996, were analysed by antibioti c resistance phenotyping, DNA macrorestriction by pulsed-field electrophore sis and isoelectric focusing of beta-lactamases. An epidemiological survey was conducted to identify risk factors for infection by ESBL Kp in this set ting. The 38 isolates were distributed into 13 antibiotypes, three of which predominated (13, six and six isolates). The DNA macrorestriction pattern identified 15 genotypes, four of which predominated (11, six, four and four isolates). A combination of the two typing methods revealed several epidem ic clones that emerged consecutively. Two main types of ESBL (SHV-2 and CTX -1) were identified by isoelectric focusing, the former predominating. The case-control study showed that the length of hospital stay, degree of malnu trition and dependency, and urinary sphincter status were the main factors significantly associated with ESBL Kp isolation.