Molecular epidemiology of a cluster of cases due to Klebsiella pneumoniae producing SHV-5 extended-spectrum beta-lactamase in the premature intensive care unit of a Hungarian hospital.

Fifteen nosocomial cases of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae occurred among 132 neonates in a premature intensive care unit in Hungary in June through November 1998. Fourteen strains were indistinguishable by molecular biological typing and harbored the same single conjugative extended-spectrum beta-lactamase-encoding plasmid that was spontaneously found in a Serratia marcescens strain in the same patient.