Epidemiological typing of extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolates responsible for five outbreaks in a university hospital

• Published in: The Journal of hospital infection Vol. 36; no. 1; pp. 23 - 36
• Main Authors: Branger, C., Bruneau, B., Lesimple, A.L., Bouvet, P.J.M., Berry, P., Sevali-Garcia, J., Lambert-Zechovsky, N.
• Format: Journal Article
• Language: English
• Published: Kent Elsevier Ltd 01.05.1997; Elsevier
• Subjects: Bacteriology; beta-Lactamases - biosynthesis; Biological and medical sciences; Cross Infection - microbiology; Disease Outbreaks; DNA, Bacterial - analysis; Drug Resistance, Microbial; extended-spectrum β-lactamase; Fundamental and applied biological sciences. Psychology; Hospitals, University; Humans; Infection Control; Klebsiella Infections - microbiology; Klebsiella pneumoniae; Klebsiella pneumoniae - classification; Klebsiella pneumoniae - genetics; Microbiology; outbreak; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Serotyping; typing; typing; extended-spectrum β-lactamase; outbreak; Klebsiella pneumoniae; Epidemic; Nosocomial infection; Typing; Drug susceptibility test; Enzyme; β-Lactamase; Epidemiology; Microbiological investigation; Bacteria; Hydrolases; Hospital; Enterobacteriaceae
• ISSN: 0195-6701; 1532-2939
• DOI: 10.1016/S0195-6701(97)90088-8

Thirty-seven isolates of extended-spectrum β-lactamase-producing (ESBL) Klebsiella pneumoniae implicated in five nosocomial outbreaks (I–V) on three distinct wards of our hospital were compared using capsular typing, biotyping, antibiotyping, enzyme electrophoresis typing and DNA macrorestriction analysis with Xba I resolved by pulsed-field gel electrophoresis. The isolates from each outbreak had common phenotypic and genotypic characteristics indicating that they were related epidemiologically. Isolates from outbreaks I (four patients) and V (13 patients), although they occurred in two different wards (neurology and surgery) and three years apart, produced the same ESBL with a pI of 7·8 (SHV-4) and were of serotype K25. The Xba I patterns were closely related. The isolates of outbreaks II (seven patients), III (four patients) and IV (seven patients), which occurred in a single surgical intensive care unit, produced an ESBL with a pI of 6·3 (TEM-3). Isolates from outbreaks III and IV, which occurred six months apart, were of serotype K68 and had similar Xba I patterns suggesting that the two outbreaks were due to a single strain which persisted endemically in the ward. The isolates from outbreak II were of serotype K62, and had distinct characteristics from the two later outbreaks. The Xba I patterns of the isolates from outbreaks ‘I and V’, II and ‘III and IV’ had Dice similarity coefficients under 40% showing that the three groups were genetically distant. DNA macrorestriction analysis was a useful complement to phenotypic methods for identifying K. pneumoniae strains responsible for outbreaks harbouring a common ESBL.