全自动血培养仪分离菌株的特征

Characteristic of Strains Isolated from BacT/Alert System in PUMCH

目的 调查全自动血培养仪分离菌株的特征。方法 从 1999～ 2 0 0 2年 2月我院全自动血培养仪培养的16 32 2瓶临床血液和无菌体液标本中 1788瓶生长菌 ,药敏试验按NCCLS纸片扩散法进行 ,数据分析用BacT/Alert仪中的分析软件及WHONET 5软件。结果 血培养阳性率 10 2 % ,无菌体液培养阳性率 30 2 % ;共检出34个属、87个种 ,需氧菌 6 2 0株 (83 8% ) ,厌氧菌 30株 (4 0 % ) ,真菌 90株 (12 2 % ) ;需氧菌中最常见的细菌是凝固酶阴性葡萄球菌 (CNS)、大肠埃希菌、金黄色葡萄球菌 ;厌氧菌最常见的细菌是脆弱拟杆菌、消化链球菌 ;真菌最常见的是白色念珠菌、近平滑念珠菌和热带念珠菌 ;血标本中大肠埃希菌和肺炎克雷伯菌的超广谱 β 内酰胺酶 (ESBLs)产生率高于非血标本 ,且ESBLs阳性的菌株对抗菌药物的耐药率明显高于ESBLs阴性菌株 ;血标本中肠球菌属对抗菌药物的耐药率明显高于非血标本 ;血培养金黄色葡萄球菌中对苯唑西林耐药 (MRSA)率 6 2 5 % ,对苯唑西林耐药的CNS产生率为 82 7%。结论 血及无菌体液中可分离培养出多种细菌和真菌 ,包括一些不常见细菌和真菌 ,注意监测血标本中菌株的耐药性 ,指导临床合理使用抗菌药物。

OBJECTIVE To investigate the characteristic of strains isolated from BacT/Alert system. METHODS A total of 1 788 isolates were collected from 16 300 culture bottles of blood and other body fluids samples by BacT/Alert in our hospital from Jan 1999 to Feb 2002. Disk diffusion method was performed according to guidelines of NCCLS (2001). BacT/Alert system and WHONET-5 software were used to analyze the data. RESULTS Thirty four genera and 87 species were obtained, including 620 aerobic isolates (83.8%), 30 anaerobic isolates (4.0%), and 90 fungi organisms (12.2%). Positive rate of blood and other body fluids culture was 10.2% and 30.2%, respectively. The most common aerobic pathogens were coagulase negative Staphylococcus(CNS), Escherichia coli and S. aureus. The most common anaerobic ones were Bacteroides fragilis and Peptostreptococcus spp. The most common fungi were Candida albicans, C. parapsilosis and C. tropicalis. The incidence of ESBLs of E. coli and Klebsiella pneumoniae in blood samples were significantly higher than those in non-blood samples. Antimicrobial resistance among ESBLs-producing strains was significantly higher than those in non-blood samples. Antimicrobial resistance of Entercoccus species to many drugs in blood samples was significantly higher than those in non-blood samples. The prevalence of oxacillin-resistant S. aureus and coagulase-negative Staphylococcus was 62.5% and 82.7%. CONCLUSIONS Many kinds of bacteria and fungi, including some uncommon pathogens can be isolated from blood samples and body fluid samples. It is important to select appropriate antimicrobial agents based on the origin of bacterial strains and avoid blindness before the results of drug sensitivity are obtained.