Objective To investigate antibiotics resistance of Proteus mirabilis isolated from stools of patients with acute diarrhea for the prevention and treatment of its infection and the rational use of antibiotics. Methods Stool samples of acute diarrhea patients were collected in the diarrhea outpatient clinic of the Second Hospital of Tianjin Medical University and Tianjin Medical University General Hospital from 2013 to 2014. Enrichment culture and biochemical identification were used to isolate and identify Proteus mirabilis, which were further performed antimicrobial susceptibility testing and class 1 integron detection. Extended spectrum β-lactamases (ESBLs) phenotype and ESBLs genes (TEM, OXA and CTX-M) were amplified by polymerase chain reaction (PCR), and sequencing were carried on in parts of suspected isolates. ESBLs-positive strains were analyzed by pulsed-field gel electrophoresis (PFGE). Results A total of 277 strains of non-repetitive Proteus mirabilis were isolated, and 268 of them were performed antimicrobial susceptibility testing (the remaining 9 strains failed to recover). Relative higher resistant rates were trimethoprim/sulfamethoxazole (30.2%), ampicillin (25.4%), nalidixic acid (25.7%), streptomycin (21.6%) and chloramphenicol (21.3%). The multiple drug resistance rate was 24.6% (66/268). The positive rate of class 1 integron was 22.8%(61/268). Resistance rates to third-generation cephalosporin, ciprofloxacin and imipenem were less than 10%, but 4 isolates were resistant to imipenem, third-generation cephalosporin, fluoroquinolones, trimethoprim/sulfamethoxazole, and chloramphenicol simultaneously. Three cefotaxime-resistant strains (1062, 1505 and 1650) were positive for ESBLs phenotype and harbored CTX-M extended-spectrum β-lactamase genes, among them 2 strains also carried TEM and/or OXA β-lactamase genes. The clustering analysis of pulsed-field gel electrophoresis (PFGE) displayed that the similarities between 1505 and 1650 were 85.7%, and the similarity with 1062 was 58.1%. Conclusion Proteus mirabilis isolated from patients with acute diarrhea in our city show significant multidrug resistance, high positive rate of class 1 integron, and emergence of ESBLs-positive strains resistant to imipenem and fluoroquinolones, which pose a threat to public health. Rational use of antibiotics is important in both clinical and nonclinical settings.%目的 了解分离自急性腹泻患者奇异变形杆菌的耐药状况,为防治其感染与合理使用抗菌药物提供依据.方法 收集2013—2014年天津医科大学第二医院和天津医科大学总医院肠道门诊急性腹泻患者粪便标本进行分离培养和生化鉴定,对鉴定得到的奇异变形杆菌进行抗菌药物敏感性试验和1类整合子聚合酶链式反应(PCR)扩增,对部分可疑菌株进行超广谱β-内酰胺酶(ESBLs)表型确证试验和PCR扩增ESBLs基因(TEM、OXA和CTX-M)并测序,对ESBLs阳性菌株进行脉冲场凝胶电泳(PFGE)分型.结果 共非重复分离到奇异变形杆菌277株,对其中268株进行了药敏试验(其余9株未能复苏成功).耐药率较高的为甲氧苄啶/磺胺甲噁唑(30.2%)、氨苄西林(25.4%)、萘啶酸(25.7%)、链霉素(21.6%)和氯霉素(21.3%),多重耐药率为24.6%(66/268).对三代头孢、环丙沙星和亚胺培南等的耐药率小于10%,但有4株菌对亚胺培南、三代头孢、氟喹诺酮、复方磺胺和氯霉素均不敏感.1类整合子阳性率为22.8%(61/268).在头孢噻肟耐药株中随机选取的3株菌(1062、1505和1650)ESBLs表型均阳性,均携带CTX-M型超广谱β-内酰胺酶基因,其中2株还同时携带TEM和(或)OXA非超广谱β-内酰胺酶基因.PFGE聚类分析显示,1505和1650相似度为85.7%,前两者与1062相似度为58.1%.结论 本地区急性腹泻患者分离的奇异变形杆菌呈现明显多重耐药,1类整合子携带率较高,出现ESBLs阳性且同时对碳青霉烯和氟喹诺酮均耐药的菌株,对公众健康构成威胁,临床和非临床领域均需要合理使用抗菌药物.
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