[Pseudo-outbreak of Stenotrophomonas maltophilia due to contamination of bronchoscope].
BACKGROUND
We noticed an abrupt increase in the isolation of Stenotrophomonas maltophilia from bronchoalveolar lavage (BAL) specimens collected at Chosun University Hospital. We performed surveillance cultures in order to identify the source of what appeared to be a pseudo-outbreak.


METHODS
To investigate a possible nosocomial outbreak of S. maltophilia, we performed culture of 11 environmental specimens obtained from a bronchoscopy room and two bronchoscopes. Pulsed-field gel electrophoresis (PFGE) was used to examine the genetic relatedness among the strains of S. maltophilia recovered from BAL specimens of 3 patients and 1 environmental sample, as well as 9 unrelated strains of S. maltophilia as a control.


RESULTS
During a 7 day-period in March 2006, S. maltophilia was isolated from the BAL specimens of 7 of 13 (54%) patients, compared to only 5 of 188 (2.6%) patients during the 6-month period prior to that period. S. maltophilia was isolated from 1 of the 11 environmental samples, which was obtained from a fiberoptic bronchoscope suction channel. All 7 patient isolates and one environmental isolate exhibited similar antibiotic susceptibility patterns. PFGE analysis of the genomic DNA from epidemic strains demonstrated an identical banding pattern, whereas each of epidemiologically unrelated strains showed a unique electrophoretic pattern.


CONCLUSIONS
Apparently one of the hospital bronchoscopes became contaminated with S. maltophilia during a bronchoscopic procedure. It is likely that subsequent specimen contamination occurred because the bronchoscope had been inadequately cleaned and disinfected. The pseudo-outbreak was controlled successfully by removing the source of infection.
Ahn
Gyun Yeol
GY
Department of Laboratory Medicine, Chosun University Medical School, Gwangju, Korea.
Yu
Feng Nan
FN
Jang
Sook Jin
SJ
Kim
Dong-Min
DM
Park
Geon
G
Moon
Dae Soo
DS
Park
Young Jin
YJ
D000368:Aged; D000369:Aged, 80 and over; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D020680:Bronchoscopes / Q000382:microbiology*; D004196:Disease Outbreaks; D016521:Electrophoresis, Gel, Pulsed-Field; D004866:Equipment Contamination; D016905:Gram-Negative Bacterial Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000635:transmission; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D020615:Stenotrophomonas maltophilia / Q000235:genetics* / Q000302:isolation & purification