广州地区3500株革兰阴性细菌的分布特征及耐药性特点

目的 了解广州地区医院感染常见革兰阴性细菌分布特征和耐药特点。方法 2001年7月-2003年8月，用Kirby—Bauer法检测了从广州地区13家医院分离获得的3500株革兰阴性细菌对临床常用15～21种抗生素的药敏结果．并按美国临床实验标准委员会2000年判断标准进行判断，用WHONET-5软件分析数据。结果 分离出的3500株革兰阴性菌中前3位细菌依次是大肠埃希菌(Echerjchia eoli，ECO)1244株(占35．5％)、肺炎克雷伯菌(Klebsiella pneumontae，Kpn)900株(占25．7％)和铜绿假单胞菌(Pseudomonas aeruginasa，Pae)547株(占15．6％)，广州地区临床分离革兰阴性菌中产超广谱β内酰胺酶(extended—spectrum beta—lactamases，ESBLs)菌株的总检出率为31．0％(1084／3500)，在各种常见菌属中的检出率分别为：大肠埃希菌为38．7％(482／1244)、肺炎克雷伯菌为37．9％(341／900)、铜绿假单胞菌为5.3％(29／547)、阴沟肠杆菌为55．2％(117／212)、不动杆菌属为8．2％(17／208)、其他肠杆菌属为27．7％(53／191)、嗜麦芽窄食单胞菌为33.3％(37／117)、变形杆菌属为9．2％(8／87).从呼吸道标本中分离获得革兰阴性细菌最多。为l463株(占41．8％)；其次为泌尿道标本，为943株(占26．9％)。耐约性分析显示：革兰阴性杆菌对临床常川抗牛素的总体耐药率最低为亚胺培南(8．7％)，其次为头孢哌酮／舒巴坦(13．3％)，而最高为氨苄西林(90．5％)，其次为余啶酸(69.3％)亚胺培南对广州地区临床分离的大肠埃希氏菌、肺炎克雷伯氏菌、阴沟肠杆菌、不动杆菌属、其他肠肝菌属和变形杆菌属的耐药率最低，分别为1．1％、0．5％、0．6％、3．2％、0．8％和0％，而头孢哌酮／舒巴坦对广州地区临床分离的铜绿假单胞菌和嗜麦芽窄食单胞菌的耐药牢最低．分别为10．8％和15．9％，大部分细菌呈多重耐药。产ESBLs菌株对15～21种临床常用抗菌药物的耐药率均显著高于不产ESBLs菌株(P《0．05)．结论细菌耐药性仍是目前广州地区临床用药最为严重的问题，尤其是产ESBLs菌株有上升趋势。业胺培南和头孢哌酮／舒巴坦分别对临床分离革兰阴性菌株有较好的抗菌活性，可以作为广州地区临床经验用药的候选药物。

Distribution and drug-resistance of 3 500 gram-negative bacteria in Guangzhou]

OBJECTIVE: To investigate the distribution and drug-resistance of the common gram-negative bacteria in Guangzhou. METHODS: From July 2001 to August 2003, the resistance of 3 500 strains of common gram-negative bacteria isolated from 13 hospitals in Guangzhou to 15 to 21 antibiotics was determined by standard Kirby-Bauer method according to the guidelines of the National Committee for Clinical Laboratory Standards (NCCLS, 2000). WHONET-5 software was used to analyze the data. RESULTS: Totally 3 500 gram-negative bacterial strains were isolated from 13 hospitals in Guangzhou in the past two years, and the top 3 most common pathogens of them were Escherichia coli (1 244 strains, 35.5%), Klebsiella pneumoniae (900 strains, 25.7%), and Pseudomonas aeruginosa (547 strains, 15.6 %). The total prevalence of extended-spectrum beta-lactamases (ESBLs)-producing strains was 31.0% (1 084/3 500). The prevalences of ESBLs-producing strains in the Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterobacter cloacae, Acinetobacter SP., other Enterobacter SP., Stenotrophomonas maltophilia, and Proteus SP. in Guangzhou were 38.7%, 37.9%, 5.3%, 55.2%, 8.2%, 27.7%, 33.3% and 9.2%, respectively. Among them, 1 463 (41.8%) strains was isolated from the respiratory tract and 943 (26.9%) from the urinary tract. According to our surveillance, the clinical antibacterial drug with the lowest total drug-resistance rates of Gram-negative bacteria was imipenem (8.7%) followed by Cefoperazone/sulbactam (13.3%), while that with the highest resistance was ampicillin (90.9%) followed by nalidixic acid (69.3%). Imipenem was the most effective agents against Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Acinetobacter SP., other Enterobacter SP., and Proteus SP. isolated from 13 hospitals in Guangzhou, with drug-resistant rates of 1.1%, 0.5%, 0.6%, 3.2%, 0.8% and 0%, respectively, whereas the most effective agents against Pseudomonas aeruginosa and Stenotrophomonas maltophilia was cefoperazone/sulbactam, with the drug-resistance rates of 10.8% and 15.9%, respectively. Most of the isolates were multi-drug resistant. The resistance rates of ESBLs-producing strains to 15 to 21 antimicrobial agents were much higher than those of non-ESBLs-producing strains (P<0.05). CONCLUSIONS: Drug resistance of the clinical isolates is a serious problem in Guangzhou, and the increasing prevalence of ESBLs-producing strains of other bacteria should be given full attention. An unanimous and effective strategy for controlling this problem is urgently needed. Imipenem and cefoperazone/sulbactam are the most effective antibiotics against the gram-negative bacteria isolated from the 13 hospitals in Guangzhou.