血液科病房临床分离菌株的变迁及耐药性分析

目的：分析我院血液科合并感染的住院患者中分离出菌株的菌谱分布和耐药现状，以了解本院血液科感染情况，为经验性抗感染治疗提供依据。方法：收集我院血液科2003年7月至2007年6月住院患者临床分离的菌株，用Kirby-Bauer纸片法检测，根据NCCLS2002标准判断结果，并应用SPSS11．0统计学软件进行统计分析。结果：共收集血液科住院患者分离菌株259株，以革兰阴性菌为主，共188株（72．6％）；其次为革兰阳性球菌71株。其中金黄色葡萄球菌及凝固酶阴性葡萄球菌（CNS）的比例呈逐年上升趋势。甲氧西林耐药金黄色葡萄球菌（MRSA）及甲氧西林敏感凝固酶阴性葡萄球菌（MRCNS）的检出率为56.3％和72．2％，且两者呈多重耐药。未发现耐万古霉素的金葡菌和肠球菌。常见的肠杆菌科主要有大肠埃希菌、肺炎克雷伯菌、阴沟杆菌，对碳青酶烯类敏感度最高。大肠埃希菌和肺炎克雷伯菌产超广谱β-内酰胺酶（ESBLs）菌株的检出率分别为70.3％和50．0％，2004年至2006年其检出率基本稳定，产ESBLs菌株交叉耐药性高于不产ESBLs株。治疗产ESBLs株感染临床应选用碳青酶烯类、酶抑制剂复合剂及头霉素类抗生素；耐喹诺酮大肠埃希菌检出率较高：非发酵菌属中机会致病菌嗜麦芽窄食单胞菌检出率有上升趋势（P〈0．05），其对碳青酶烯类天然耐药，临床首选复方新诺明。铜绿假单胞菌和鲍曼／溶血不动杆菌对亚胺培南耐药率为8．8％和6．2％，其后敏感率从高到低依次为派拉西林或头孢他啶、酶抑制剂复合制剂、氨基糖苷类。结论：血液系统疾病临床分离菌株多重耐药情况严重，本研究结果对经验性治疗有一定参考价值。

Trends of bacterial strains isolated and their antimicrobial resistance in hematology ward

Objective To investigate the incidence and antimicrobial resistance of bacterial strains isolated from hospitalized patients in hematology ward.Methods A total of 259 bacterial strains were isolated from 1,849 hematology ward patients from July 2003 to June 2007.Antimicrobial susceptibility was tested by Kirby-Bauer method and the data col- lected were analyzed with SPSS11.0 software.Results Among the 259 strains isolated,71(27.4%)were Gram-positive and 188(72.6%)were Gram-negative organisms.The incidence of Staphylococcus Aures and coagulase negative staphylococci had a tendency to increase.MRSA(methicillin resistant Staphylococcus A ures)and MRCNS(methicillin-resistant coagulase- negative Staphylococci)accounted for 56.3% and 72.2% of the Staphylococcus aureus and coagulase negative staphylococci isolated,respectively.Most of the strains had multiple drug resistance.No vancomycin resistant strain of Staphylococcus spp. and Enterococcus spp.was found.The 6 most frequently isolated species of Gram-negative bacilli were Escherichia coil,En- terobacter cloacae,A cinetobocter baumannii,Klebsiella pneumoniae,Pseudomonas aeruginosa and Haemaphilus influenzae. Carbapenems had high activity against Acinetobacter spp.and most isolates of Enterobacteriaae.Detection rates of ESBLs- producing strains in E.coli and K.pneumoniae were 70.3% and 50.0%,respectively.Antimicrobial cross-resistance rate of ESBLs-producing strains was higher than that of ESBLs-nonproducing strains.For ESBLs-producing strains,carbapenems, enzyme inhibitor complex and cephalosporins should be selected;the detection rate of quinolone-resistant Escherichia coli was quite high.Among non-fermentaters,the detection rate of opportunistic pathogen Stenotrophomonas maltophilia had a tendency to increase(P<0.05)and was resistant to carbapenems;SMZ/TMP was the drug of choice.Pseudomonas aeroginosa and Acinetobacter baumannii had an imipenem-resistant rate of 8.8% and 6.2% respectively,followed by piperacillin,cef- tazidime,enzyme inhibitor complex and aminoglycosides as their sensitive antimierobials.Conclusions The data may have some significance for the empirical use of antimierobial agents in the treatment of infections in hematology ward patients.