西安某医院临床分离嗜麦芽窄食单胞菌的临床分布及毒力基因检测

Clinical distribution and prevalence of virulence genes of Stenotrophomonas maltophilia strains in a hospital in Xi′an

目的了解嗜麦芽窄食单胞菌的临床感染特点、抗菌药物敏感性及毒力基因携带情况,为嗜麦芽窄食单胞菌的感染控制提供数据支持。方法收集该院2017年1月至2018年12月分离的嗜麦芽窄食单胞菌79株,剔除重复菌株,对其临床感染特点进行总结分析,用纸片扩散法检测嗜麦芽窄食单胞菌对3种抗菌药物的敏感性;采用改良微孔板法分析其生物膜形成能力;PCR检测4种主要毒力基因(Stmpr1、Stmpr2、smf-1、Smlt3773locus)的携带状况。结果临床分离的79株嗜麦芽窄食单胞菌主要来自痰标本62例、肺泡灌洗液6例、分泌物8例、尿液3例;分离率最高的科室是呼吸及重症医学科29例,其次是神经外科28例,其余来自全科医学科、内分泌科、肾病血液科及骨科等;嗜麦芽窄食单胞菌感染患者中,男性居多,有51例(64.6%);大多数患者在检测到嗜麦芽窄食单胞菌前均使用过2~5种抗菌药物,其中抗菌药物的使用种类大于3种的患者占比高达64.5%,主要的抗菌药物为头孢菌素类(82.3%)、碳青霉烯类(53.1%)和含酶抑制剂复合制剂(63.3%)。79株菌株对左氧氟沙星、甲氧苄啶-磺胺甲噁唑的耐药率分别为12.6%和3.8%,未发现对米诺环素耐药的菌株。生物膜形成试验的结果表明,生物膜形成能力A 492为0.50±0.42,不同性别患者间差异无统计学意义(P>0.05)。毒力基因检测显示,Stmpr1、Stmpr2、smf-1、Smlt3773locus的阳性率较高,分别为75.9%、91.1%、93.7%和44.3%。结论嗜麦芽窄食单胞菌检出以男性患者居多,且大多数患者有多种抗菌药物的应用史,细菌毒力基因携带率较高。

Objective To investigate the clinical characteristics of Stenotrophomonas maltophilia infection,antimicrobial susceptibility and virulence gene carrying status,so as to provide data support for the infection control of Stenotrophomonas maltophilia.Methods A total of 79 strains of Stenotrophomonas maltophilia isolated in the hospital from January 2017 to December 2018 were collected and the repetitive strains were eliminated,and the clinical characteristics of infection were summarized and analyzed.The sensitivity of Stenotrophomonas maltophilia to three antimicrobial agents was detected by disk diffusion method,and the biofilm formation ability was analyzed by improved microplate method.PCR was used to detect the carrying status of four major virulence genes(Stmpr1,Stmpr2,smf-1,Smlt3773locus).Results A total of 62 strains(78.5%)were isolated from sputum specimens,6 strains were isolated from bronchoalveolar lavage fluid,8 strains from secretion and 3 strains from urine.The isolation rate was highest in Department of Respiratory and Severe Diseases Medicine(29 cases),followed by the Department of Neurosurgery(28 cases),and the rest were from Department of General Medicine,Department of Endocrinology,Department of Kidney Hematology and Department of Orthopaedics.A total of 51 strains(64.6%)were from male patients.Most patients used 2-5 kinds of antibiotics before detection of Stenotrophomonas maltophilia,and 64.5%of the patients used more than 3 kinds of antibiotics,and the main antibiotics were cephalosporins(82.3%),carbapenems(53.1%)and enzyme inhibitors(63.3%).The resistance rates of 79 strains to levofloxacin and trimethoprim sulfamethoxazole were 12.6%and 3.8%respectively and no minocycline resistant strain was found.The results of biofilm formation test showed that the average value A 492 of biofilm formation ability was 0.50±0.42,and there was no significant difference between different genders.Vir ulence gene detection results showed that the positive rates of Stmpr1,Stmpr2,smf-1 and Smlt3773locus were relatively high,75.9%,91.1%,93.7%and 44.3%respectively.Conclusion Stenotrophomonas maltophilia is mainly detected in male patients,and most of the patients have a history of multiple antimicrobial agents,and the bacterial virulence gene carrying rate is high.