腹部外科常见的厌氧菌感染及其快速诊断

Anaerobic infections in abdominal surgery and its rapid diagnosis in intra-abdominal infections

目的 研究阐明腹部外科常见厌氧菌感染的致病菌及其特点 ,探索将气相色谱 (GLC)应用于这类感染的快速诊断。方法 用常规细菌学检验和直接显微镜观察结合GLC定量分析厌氧菌特征性代谢产物———短链脂肪酸 (SCFA)。两种方法分别检测 42 1例腹腔感染标本。结果 常规细菌学检验 32 6例细菌培养阳性。单独厌氧菌和需氧 (或兼性厌氧 )菌感染分别为 34例 (8.1% )和 83例 (19.7% ) ;厌氧菌与需氧 (或蒹性厌氧 )菌混合感染 2 0 9例 (4 9.6 % )。厌氧菌培养阳性 2 43例 (5 7.7% )。常见厌氧菌是脆弱类杆菌组和其他类杆菌、G+厌氧球菌和链球菌 ;常见需氧 (或蒹性厌氧 )菌是大肠埃希菌、其他肠杆菌、铜绿假单胞菌和其他假单胞菌、粪肠球菌和其他肠球菌。GLC直接检出标本中SCFA为 6 2 .9% (2 6 5 /4 2 1)。其诊断厌氧菌感染的敏感性和特异性分别为 85 .3% (2 2 6 /2 6 5 )和 89.1% (139/15 6 )。GLC直接检测与标本显微镜观察可将 88.5 % (2 0 0 /2 2 6 )的厌氧致病菌鉴定至属或种。结论 GLC直接检测腹腔感染标本可在几小时内诊断厌氧菌感染。随着方法的改进 ,GLC将更适合临床快速诊断 ,这对深化厌氧菌感染的认识、普及和提高诊断外科厌氧菌感染的水平、指导临床合理应用有效抗生素、减少盲目性有重要意义。

Objective To study the characteristics of intra abdominal infections with anaerobic bacteria and the applicability of short chain fatty acids(SCFAs) analysis using gas liquid chromatography (GLC) for rapid diagnosis. Methods 421 specimens of intrabdominal infections were examined both by the conventional bacteriology method as well as the non culture quantitative procedure of GLC to analyze directly the SCFAs(volatile and nonvolatile acids).Results Pathogenic bacteria were isolated in 326 specimens(77.4%)with anaerobes only in 34(8.1%),aerobic or facultative anaerobic bacteria only in 83(19.7%),mixed aerobic anaerobic in 209(49.6%). Thus, from all samples, anaerobic bactria were identified in 243cases(57.7%) in total. The predominant anaerobes included Bacteroides fragilis group and other Bacteroides spp, Peptostreptococcus spp and gram positive anaerobic cocci. The predominant aerobic and facultative bacteria included Escherichia coli, Enterobacteriaceae, Pseudomonas aeroginosa and Pseudomonas spp, other nonfermenters, Enterococcus faecalis and other Enterococcus spp. GLC showed SCFAs in 62.9%(265/421) of specimens directly.The sensitivity and specificity of the GLC for diagnosis of intra abdominal infections with anaerobes were 85.3%(226/265) and 89.1%(139/156)respectively; 88.5%(200/226) of anaerobes were correctly identified to the species or genus level with GLC and bacterioscopy. Conclusion The direct GLC assay of specimens combining with bacterioscopy can detect anaerobes of intra abdominal infections within several hours. Further developments in GLC technology can provide rapid, accurate and more applicable techniques for diagnosis of intra abdominal infections with anaerobes. The system may replace conventional bacteriology as an alternate diagnostic method for anaerobic infections in surgery. It will correct the common malpractice of administering empiric and prolonged courses of broad spectrum antibiotics in the treatment of intra abdominal infections, thus upgrade the effect of resolving anaerobic infections in surgery.