배경: 2006년 5월부터 기관지 세척액 배양에서 Klebsiella oxytoca의 분리 빈도가 갑작스럽게 증가하였다. 이에 저자들은 K. oxytoca에 의한 돌발 감염을 의심하여 감염원을 찾기 위한 역학 조사 및 추가발생을 감소시키기 위한 감염활동을 실시 하였다. 방법: 총 18검체를 대상으로 하였다. K. oxytoca 14주는 기관지 내시경실 전용 기관지 내시경 장비에서, 나머지 4주는 내과 중환자실에서 사용했던 이동식 기관지 내시경 장비에서 검출되었다. 환자들의 병력과 미생물 검사 결과를 통해 감염 유무를 조사하였고, 기관지 내시경 기구 및 환경 검체에 대한 배양검사를 실시하였다. 분자역학적 연관성을 확인하기 위하여 보관이 가능하였던 10주를 대상으로 pulsed-field gel electrophoresis를 실시하였다. 결과: 환자들의 병력조사에서 기관지 내시경 시행 전후 K. oxytoca에 의한 호흡기 감염발생 증거는 없었다. 2대의 기관지 내시경 기구 및 환경 검체에 대한 배양검사 결과 K. oxytoca는 검출되지 않았다. Pulsed-field gel electrophoresis 유전자 형별분석 결과 8주에서 유사한 패턴이 관찰되었다. 가유행의 역학조사 기간 동안 기관지 내시경의 세척, 소독 강화 및 지속적인 감염관리 활동으로 이후 K. oxytoca 검출빈도는 점차 감소하였다. 결론: 기관지 세척액 배양에서 K. oxytoca 분리 빈도의 갑작스런 증가는 가유행으로 판명되었으며, 역학조사상 감염원은 기관지 내시경 검사 당시 해당 균을 상재하고 있던 환자로 추정하였다.

Background: We noticed a sudden increase in the isolation of Klebsiella oxytoca from bronchial washing specimens during May to June 2006. An epidemiological investigation was conducted to identify the cause of the outbreak and to implement appropriate infection control measures. Methods: A total of 18 isolates of K. oxytoca were found. The 14 bronchial washing specimens that yielded K. oxytoca were taken in the outpatient bronchoscopy suite, and the other 4 specimens were obtained by a portable bronchoscopy. The medical records and microbiologic findings of these patients were reviewed. Environmental samples from two bronchoscopes and the bronchoscopy suite were cultured. The relations between the available 10 isolates from bronchial washing fluid were investigated by pulsed- field gel electrophoresis (PFGE). Results: No patients were judged to have had true infections attributable to K. oxytoca either before or after bronchoscopy. Cultures of samples from two bronchoscopes and related environment did not grow K. oxytoca. The PFGE analysis showed that 8 of 10 isolates had a similar pattern of DNA fragments. An infection control strategy was implemented, including adequately cleaning and disinfecting the bronchoscopes, and a sharp reduction in the incidence of K. oxytoca from bronchial washing samples followed. Conclusion: The sudden increase of K. oxytoca from bronchial washing specimens was a pseudo-outbreak. We presumed that the bronchoscopes became contaminated during a procedure in a patient colonized with K. oxytoca in the upper-respiratory tract.

Background: We noticed a sudden increase in the isolation of Klebsiella oxytoca from bronchial washing specimens during May to June 2006. An epidemiological investigation was conducted to identify the cause of the outbreak and to implement appropriate infection control measures. Methods: A total of 18 isolates of K. oxytoca were found. The 14 bronchial washing specimens that yielded K. oxytoca were taken in the outpatient bronchoscopy suite, and the other 4 specimens were obtained by a portable bronchoscopy. The medical records and microbiologic findings of these patients were reviewed. Environmental samples from two bronchoscopes and the bronchoscopy suite were cultured. The relations between the available 10 isolates from bronchial washing fluid were investigated by pulsed- field gel electrophoresis (PFGE). Results: No patients were judged to have had true infections attributable to K. oxytoca either before or after bronchoscopy. Cultures of samples from two bronchoscopes and related environment did not grow K. oxytoca. The PFGE analysis showed that 8 of 10 isolates had a similar pattern of DNA fragments. An infection control strategy was implemented, including adequately cleaning and disinfecting the bronchoscopes, and a sharp reduction in the incidence of K. oxytoca from bronchial washing samples followed. Conclusion: The sudden increase of K. oxytoca from bronchial washing specimens was a pseudo-outbreak. We presumed that the bronchoscopes became contaminated during a procedure in a patient colonized with K. oxytoca in the upper-respiratory tract.