血培养病原菌的分布及耐药性分析

目的 了解血液标本培养中病原菌的分布及耐药情况,以指导临床合理用药.方法 收集2008年1月至2009年12月我院血培养标本3277份,采用Bactec 9120型全自动血培养仪进行培养,MicroScan全自动微生物鉴定仪进行鉴定和药敏试验,采用WHONET 5.4软件进行结果分析.结果 3277份血培养标本中分离出病原菌452株,阳性率13.8％.其中革兰阳性菌221株,占48.9％,革兰阴性菌198株,占43.8％,真菌33株,占7.3％.最常见的病原菌分别是凝固酶阴性葡萄球菌（coagulase negative Staphylococcus,CNS）116株（25.7％）、大肠埃希菌88株（19.5％）、金黄色葡萄球菌（Staphylococcus aureus,SA）44株（9.7％）.88株大肠埃希菌检出产ESBLs菌30株,产酶率为34.1％；36株肺炎克雷伯菌检出产ESBLs菌8株,产酶率为22.2％.SA、CNS对青霉素、苯唑西林、红霉素、克林霉素和复方新诺明的耐药率较高,均大于45.0％；未发现对万古霉素、替考拉宁耐药的革兰阳性菌株；大肠埃希菌、肺炎克雷伯菌对亚胺培南、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦、阿米卡星的敏感性较好,耐药率均小于20.0％.结论 血培养病原菌种类复杂,耐药率高,临床医生应及时监测病原菌的变化及耐药趋势,采取合理的抗菌治疗,控制院内感染.

Distribution and drug resistance of bacteria isolated from blood specimens

Objective To investigate the distribution and drug resistance of the pathogenic bacteria in blood culture and to direct usage of antimicrobial agents in clinic. Methods 3277 blood culture samples from January 2008 to December 2009 in our hospital were collected. The blood samples were cultivated in the Bactec 9120 system. Isolated colonies were identified and drug sensitivity was tested by MicroScan system. WHONET 5.4 software was used to analysis datas. Results 452 strains of pathogenic bacteria were isolated from 3277 blood specimens, the positive rate was 13.8%. Gram-positive （221 strains） and Gram-negative （198 strains） bacilli isolated accounted for 48.9% and 43.8%, and fungi for 7.3%（33 strains）. The most frequent isolated were coagulase negative Staphylococcus（CNS） 116 strains（25.7%）, Escherichia coli 88 strains（19.5%）, Staphylococ- cu, s aureus （SA） 44 strains（9.7%）. There were 30 strains Escherichia coli producing extended spectrum β lacta- mases（ESBLs） in 88 strains accounting 34.1%, and 8 strains Klebsiella pneumoniae producing ESBLs in 36 strains accouting 22.2%. The drug resistance of SA and CNS to penicillin, oxacillin, erythrocin, clindamycin and cotrimoxazole were all higher than 45.0%. No strains resistant to vancomycin and teicoplanin were found in Gram-positive cocci. The drug resistance of Escherichia coli and Klebsiella pneumoniae to imipenem, piperacillin/tazabactam, cefoperazone/sulbactam and amikacin were all lower than 20.0%. Conclusion There are many kinds of pathogens identified from blood culture, and the drug resistance is high. Clinicians should monitor the change of pathogens and trends of drug resistance in time, in order to give the patient correct antibi- otic therapy and to control cross-infection in hospitals.