新生兒加護病房Klebsiella pneumoniae群突發感染事件調查

Investigating outbreak of Klebsiella pneumoniae infection in a Neonatal Intensive Care Unit

2015年7月14日至2015年10月31日於台北市某醫學中心新生兒加護病房，發生克雷伯氏肺炎菌（Klebsiella pneumoniae）感染或移生造成的群突發事件，這期間共有12位病人檢體培養出K. pneumoniae，10位為醫療照護相關感染（8位血流感染、1位腸胃道感染、1位泌尿道感染）及2位痰液移生；而這12位病人菌株培養的抗生素敏感試驗結果，有11位病人的抗生素敏感試驗結果對第三代頭孢菌素（Third-generation cephalosporins）產生抗藥性，抗藥性的比例為92％（11／12）；於流行期間針對醫護人員進行手部衛生採檢，採檢10件檢體有2件培養出K. pneumoniae，陽性率為20％（2／10）；並使用ATP（adenosine triphosphate）──生物冷光檢測法進行環境清潔度檢測，採檢12件檢體，檢測結果不合格率為36.3％（4／12）；8位血流感染病人中，有7位分別置放臍動靜脈導管或中心靜脈導管，依據侵入性醫療裝置相關感染監測定義，判定有6位為中心導管相關血流感染，導管置放日至感染日平均天數為11±7.9天。此事件經流行病學調查未找到共同感染源，但在醫護人員手部採檢到相同細菌，因此推測可能與醫護人員未能落實手部衛生以及環境清潔消毒未確實所造成的交叉感染，群突發事件以血流感染居多且新生兒加護病房因病人特性，無導入中心靜脈導管組合式照護措施central venous catheter（CVC）bundle，故本事件介入之感染管制措施包括：導入修改過CVC bundle、加強人員教育訓練、落實手部衛生、將感染及移生的病人集中照護並採接觸隔離措施、加強環境清潔──包括儀器設備及環境清潔順序流程化、改用單次拋棄式紙巾清潔消毒環境、並增加清潔頻次、空間及硬體設備改善等。該單位自2015年11月後，即無K. pneumoniae的感染及移生新案發生。 An outbreak of Klebsiella pneumoniae infection occurred in a Neonatal Intensive Care Unit (ICU) of Taipei medical center from July through October 2015, during which time K. pneumoniae was isolated from 12 critically ill neonates. Of these, 10 were identified as health-care associated infections (8 blood stream, 1 urinary tract, 1 gastrointestinal tract) and 2 were sputum colonization. Although the antibiotic susceptibility of 12 K. pneumoniae isolates from patients was not completely identical, 11of 12 (92%) were ESBL (Extended-spectrum β-lactamases) strains which were resistant to 3rd generation cephalosporins. We used ATP (Adenosine triphosphate) bioluminescence method to detect environmental cleanliness. Of 12 collected environmental sample, detection result of the failure rate was 36.3% (4/12). Besides, among the 8 patients with blood stream infection, seven had placement of central venous catheter (CVC) and/or umbilical arteriovenous catheter before infections. Six of them were identified as catheterrelated blood steam infection according to CDC definition. The mean interval from catheter insertion to infection was 11.2 ±7.9 days. Epidemiological investigation failed to reveal a common source of the outbreak, although the epidemic K. pneumoniae strain was isolated from hand-washes. We inferred that cross-transmission was the major route for this outbreak. Besides, we found that catheter-related blood stream infection played an important role in this outbreak. However, central venous catheter (CVC) bundle was not introduced in neonatal ICU before due to patient characteristics. Therefore, the management of this outbreak included: implementing a modified CVC care bundle, strengthen staff education and training, strict handwashing practices, cohorting and isolation of colonized and infected patients, aggressive cleaning of the environment surfaces with disposable paper towels, and ICU space improvement. The outbreak was successfully controlled, no further K. pneumoniae infection was identified since Nov 2015.