Journal

The Journal of the Japanese Society for Clinical Microbiology

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[Vol.17 No.4 contents]
Japanese / English

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Article in Japanese

ArticleTitle Outbreak of Pseudomonas aeruginosa Mediated by Reused Bite-Block Devices and Its Prevention
Language J
AuthorList Kazuhisa Ugajin1), Mayumi Togashi1), Setsuko Tazawa1), Kenji Marumo2), Kazumi Taguchi2), Mieko Yamanaka3), Toshiki Kikuchi4), Goroh Nagashima5), Hironori Tanaka6)
Affiliation 1) Division of Clinical Laboratory
2) Department of Clinical Pathology
3) Intensive Care Unit
4) Department of Respiratory Medicine
5) Department of Brain Surgery
6) Division of Pharmacy, Showa University Fujigaoka Hospital
Publication J.J.C.M.: 17 (4), 277-283, 2007
Received October 17, 2006
Accepted August 20, 2007
Abstract In the intensive care unit (ICU) of Showa University Fujigaoka Hospital, Pseudomonas aeruginosa was isolated from mainly respiratory tract-derived specimens of 20 patients in July 2004: the weekly patient number demonstrating the organism(mean ± 2x standard deviation=6.2 ± 2.5 patients per week, n=5 weeks of the month) was much greater than the previously recorded numbers(1.6 ± 2.2 patients per week, n=52 weeks between July 2003 and June 2004). This abnormal number represented a serious outbreak in the ICU. P. aeruginosa isolates from 7 of 9 patients with orotracheal intubation were resistant to imipenem and ciprofloxacin by MicroScan testing, although those from the 2 remaining patients were susceptible to these agents. Furthermore, the bite-block devices had been repeatedly cross-reused after disinfection with 140 ppm chlorine. A case-control study showed that the reuse of these bite-block devices was significant risk factor for the pseudomonal outbreak(odds ratio, 7.6; 95% confidence interval, 2.37 to 24.62). Thus, we suspected pseudomonal cross-contamination of the devices, since routes of other cross-contamination had been denied. Of 5 P. aeruginosa isolates from these devices, 4 and 1 were resistant and susceptible to the two antimicrobial agents, respectively. Identical clones of the 7 and 2 isolates from the previous 9 patients with pulsotypes A and B, respectively, were included in the clones isolated from these devices. These results strongly support the pseudomonal cross-contamination mediated by reuse of bite-block devices. Strategies for preventing such pseudomonal contamination were strictly implemented using standard precautions by medical staff, while a disposable bite-block device was introduced. Thus, the patient numbers dramatically decreased in the previously recorded level. This study suggests the importance of surveying the weekly patient number of P. aeruginosa infection to prevent hospital-acquired infection and rapidly implementing measures to control such infection.
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