Neonatal intensive care unit outbreak caused by a strain of Klebsiella oxytoca resistant to aztreonam due to overproduction of chromosomal beta-lactamase

Citation
Sh. Jeong et al., Neonatal intensive care unit outbreak caused by a strain of Klebsiella oxytoca resistant to aztreonam due to overproduction of chromosomal beta-lactamase, J HOSP INF, 48(4), 2001, pp. 281-288
Citations number
17
Categorie Soggetti
Clinical Immunolgy & Infectious Disease
Journal title
JOURNAL OF HOSPITAL INFECTION
ISSN journal
01956701 → ACNP
Volume
48
Issue
4
Year of publication
2001
Pages
281 - 288
Database
ISI
SICI code
0195-6701(200108)48:4<281:NICUOC>2.0.ZU;2-Q
Abstract
Klebsiella oxytoca strains resistant to both aztreonam and ceftriaxone were isolated from six neonates in a neonatal intensive care unit and water res ervoirs of two humidifiers attached to the neonatal incubators. These isola tes were assumed to be of the same clone because they were characterized by the same antimicrobial susceptibility and pulsed field gel electrophoresis patterns. It was established that the drug resistance was attributed to ov erproduction of chromosomally encoded K1 beta -lactamase. It was determined that an isolate (K. oxytoca H1) contained a high enzyme concentration (27 mug/100 tg of protein in enzyme extracts), at least 27 times higher than th e control K. oxytoca N1. It was also demonstrated that isolates had a point mutation in the - 35 concensus region of the promotor gene of bla(OXY-2) l eading to enzyme overproduction. Outbreaks caused by K1 hyperproducers have not previously been described. (C) 2001 The Hospital Infection Society.