Liu Guoye, Qian Huimin, Lv Jingwen, Tian Benshun, Bao Changjun, Yan Hong, Gu Bing
Department of Clinical Laboratory, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China.
Department of Acute Infectious Disease Prevention and Control, Jiangsu Provincial Center for Disease Prevention and Control, Nanjing, China.
Front Microbiol. 2021 Sep 3;12:723697. doi: 10.3389/fmicb.2021.723697. eCollection 2021.
This study analyzed the antimicrobial resistance phenotypes and mechanisms of quinolone, cephalosporins, and colistin resistance in nontyphoidal from patients with diarrhea in Jiangsu, China. A total of 741 nontyphoidal isolates were collected from hospitals in major cities of Jiangsu Province, China between 2016 and 2017. Their susceptibility to commonly used antibiotics was evaluated by broth micro-dilution and sequencing analysis of resistance genes screened by a PCR method. For positive isolates, genetic relationship study was carried out by pulsed-field gel electrophoresis and multiloci sequence typing analysis. The transferability of these plasmids was measured with conjugation experiments and the genetic locations of were analyzed by pulsed-field gel electrophoresis profiles of S1-digested genomic DNA and subsequent Southern blot hybridization. Among 741 nontyphoidal isolates, the most common serotypes identified were Typhimurium (=257, 34.7%) and Enteritidis (=127, 17.1%), and the isolates showed 21.7, 20.6, and 5.0% resistance to cephalosporins, ciprofloxacin, and colistin, respectively. Among the 335 nalidixic acid-resistant , 213 (63.6%) and 45 (13.4%) had at least one mutation in and . Among the plasmid-borne resistance, (85; 41.9%) and (75; 36.9%) were the most common quinolone resistance (PMQR) genes, while (=35) and (=46) were found to be dominant extended-spectrum beta-lactamase (ESBL) genes in nontyphoidal . In addition, eight -harboring strains were detected since 2016 and they were predominate in children under the age of 7years. Conjugation assays showed the donor strain has functional and transferable colistin resistance and Southern blot hybridization revealed that was located in a high molecular weight plasmid. In nontyphoidal , there is a rapidly increasing trend of colistin resistance and this is the first report of patients harboring -positive with a new ST type ST155 and new serotype Sinstorf. These findings demonstrate the necessity for cautious use and the continuous monitoring of colistin in clinical applications.
本研究分析了中国江苏腹泻患者非伤寒沙门氏菌对喹诺酮、头孢菌素和黏菌素的耐药表型及机制。2016年至2017年期间，从中国江苏省主要城市的医院收集了741株非伤寒沙门氏菌分离株。通过肉汤微量稀释法评估其对常用抗生素的敏感性，并对通过PCR方法筛选的耐药基因进行测序分析。对于阳性分离株，通过脉冲场凝胶电泳和多位点序列分型分析进行遗传关系研究。通过接合实验测定这些质粒的可转移性，并通过S1酶切基因组DNA的脉冲场凝胶电泳图谱及随后的Southern印迹杂交分析黏菌素耐药基因的遗传位置。在741株非伤寒沙门氏菌分离株中，鉴定出的最常见血清型为鼠伤寒沙门氏菌（=257株，34.7%）和肠炎沙门氏菌（=127株，17.1%），这些分离株对头孢菌素、环丙沙星和黏菌素的耐药率分别为21.7%、20.6%和5.0%。在335株耐萘啶酸的非伤寒沙门氏菌中，213株（63.6%）和45株（13.4%）在gyrA和parC中至少有一个突变。在质粒介导的耐药性中，qnrS（85株；41.9%）和qnrB（75株；36.9%）是最常见的喹诺酮耐药（PMQR）基因，而blaCTX-M（=35株）和blaTEM（=46株）被发现是非伤寒沙门氏菌中占主导地位的超广谱β-内酰胺酶（ESBL）基因。此外，自2016年以来检测到8株携带mcr-1的菌株，且它们在7岁以下儿童中占主导地位。接合试验表明供体菌株具有功能性且可转移的黏菌素耐药性，Southern印迹杂交显示mcr-1位于高分子量质粒中。在非伤寒沙门氏菌中，黏菌素耐药性呈快速上升趋势，这是首次报道携带mcr-1阳性非伤寒沙门氏菌且具有新的ST型ST155和新血清型Sinstorf的患者。这些发现表明在临床应用中谨慎使用和持续监测黏菌素的必要性。
