Methods: The index case was found incidentally from a clinical stool culture which grew MBL-producing Klebsiella pneumoniae. Because the isolated organism was an unusual, resistant strain, rectal swab screening was performed for the other patients in the ward, 6 of whom were later found to be positive for MBL-producing enterobacteriaceae. Once-weekly active surveillance by rectal swab was implemented and an environmental investigation was performed by internal and external teams. A retrospective cohort study was conducted to identify the factors associated with the transmission of MBL-producing enterobacteriaceae. Genotyping of isolates was performed by next generation sequencer.
Results: Of the 249 patients admitted to the ward, 382 samples were obtained from 145 patients (58%) by means of active surveillance cultures. MBL-producing enterobacteriaceae were isolated from 36 patients (25%). None of them developed any clinical diseases. K. pneumoniae and Escherichia coli were predominant among the isolates. Environmental cultures also revealed MBL-producing K. pneumoniae in a sink, a formula-bottle cabinet, a cold tea dispenser, and the tea itself. All isolated organisms from the surveillance and environmental cultures possessed the blaIMP-1 gene. Drinking tea from the tea dispenser was associated with MBL-producing enterobacteriae colonization (adjusted odds ratio, 43.7; 95% confidence interval 7.3-260.5). After use of the tea dispenser was banned, the outbreak ceased.
Conclusion: This is the first report of a contaminated tea dispenser in a hospital being associated with an MBL-producing eneterobacteriaceae outbreak. Awareness of the potential for transmission of MBL-producing enterobacteriaceae via such routes should be noted.
M. Yoshida, None
K. Aoki, None
Y. Ishii, None
Y. Horikoshi, None