Antimicrobial resistance profiles of Salmonella paratyphi A isolates collected from 3 outbreaks in Fuchuan County of Guangxi, 2000-2018

Objective To describe and compare the profiles and evolution of antimicrobial resistance in Salmonella paratyphi A isolates collected from different years in Fuchuan County of Guangxi, through in vitro drug sensitivity tests, and we provide scientific evidence for formulating surveillance programs and control policies. Methods A panel of 122 isolates of Salmonella paratyphi A were obtained from 3 outbreaks in Fuchuan County of Guangxi, 2000-2018, and tested for minimum inhibitory concentrations (MIC) of antibiotics by the broth dilution method. Results The 122 strains were all susceptible (100.00%) to ampicillin, ampicilli / sulbactam, cotrimoxazole, cefotaxime, ceftazidime, gentamicin, azithromycin, imipenem and sulfamethoxazole. Over 90.00% of them were susceptible to tetracycline, chloramphenicol and cefoxitin. Only 71.31% of them were susceptible to cefazolin. They manifests as drug-resistance and intermediate to quinolones: The intermediate rate of ciprofloxacin is 97.54%; nalidixic acid is entirely 100.00% resistance. Cefotaxim, ceftazidime and gentamicin show the best antibacterial effects, and the phenomenon of multidrug resistance is not severity. No strains resistant to third-generation cephalosporin were detected. Conclusion Third-generation cephalosporins should be accepted as a drug of first choice for Salmonella paratyphi A. And quinolones should be used with caution. Enhanced surveillance of antimicrobial resistance in Salmonella paratyphi A is essential to provide an evidence base for empirical treatment protocols. 摘要：目的 通过体外药物敏感性试验, 了解广西富川县不同年度甲型副伤寒沙门菌对15种抗生素的敏感性及耐 药变迁, 为甲型副伤寒的疾病监测及防治策略提供实验数据。 方法 采用微量肉汤稀释法对广西富川县2000—2018 年三起甲型副伤寒疫情分离的122株甲型副伤寒沙门菌进行药敏试验, 分析不同最低抑菌浓度（MIC)检测结果。 结果 122株甲型副伤寒沙门菌对氨苄西林(AMP)、氨苄西林/舒巴坦(AMS)、复方新诺明(SXT)、头孢噻肟(CTX)、头孢 他啶(CAZ)、庆大霉素（GEN)、阿奇霉素(AZI)、亚胺培南(IMI)和磺胺异恶唑(SUL)等9种药物敏感率达100.00%, 四环 素(TET)、氯霉素(CHL)和头孢西丁(CFX)敏感率也达90.00%以上, 头孢唑啉(CFZ)敏感率仅为71.31%;对喹诺酮类药 物主要表现为耐药和中介:环丙沙星(CIP)中介率为97.54%, 萘啶酸(NAL)100.00%耐药。CTX、CAZ和GEN三种药物 抑菌效果最佳, 多重耐药现象不严重, 未出现耐三代头孢药物菌株。 结论 第三代头孢药物可作为治疗甲型副伤寒 的首选药物, 慎用喹诺酮类药物；同时应加强常用抗生素耐药监测, 结合本地实际情况, 合理选用治疗甲型副伤寒的首 选和常规药物。