侵袭性非伤寒沙门菌血清型和耐药性分析

Analysis on serotype and antimicrobial resistance of invasive non-typhoidal Salmonella

目的分析7株侵袭性非伤寒沙门菌(iNTS)的血清型和耐药性。方法针对收集的7株iNTS菌株,开展血清学鉴定、药物敏感性实验以及全基因组测序,并对血清型、MLST型和耐药基因进行鉴定、注释和分析。结果7株iNTS菌株中,包含1株鼠伤寒血清型和2株Ⅰ4,[5],12:i:-(ST34型)、2株肠炎血清型、1株科瓦利斯血清型和1株未知血清型Ⅰ4,[5],12:d:-(ST279型),其中6株为单相菌,沙门菌二相鞭毛基因缺失或假基因化可能有助于增强沙门菌侵袭性。未发现替加环素、氨曲南、阿米卡星及头孢类、碳青霉烯类抗生素耐药株,存在1株八重耐药鼠伤寒沙门菌。耐药基因与耐药表型基本相符。结论本研究中的iNTS菌株存在八重耐药株,整体耐药水平尚低但不可忽视。

Objective To investigate the serotypes and antimicrobial resistance of seven invasive non-typhoidal Salmonella(iNTS)isolates.Methods For 7 iNTS strains collected,serotype identification,antimicrobial susceptibility testing and whole genome sequencing were performed.We identified,annotated and analyzed the serotypes,MLST types,and antimicrobial resistance genes.Results Among the 7 tested iNTS isolates,we found one Salmonella Typhimurium strain and two SalmonellaⅠ4,[5],12:i:-strains whose MLST types were ST34,two Salmonella Enteritidis strains,one Salmonella Corvallis strain and one strain of unknown serotype with the antigenic formulae ofⅠ4,[5],12:d:-(ST279 type).Six of seven strains were monophasic and the deletion or pseudogenization of Salmonella Flagellum gene might contribute to the enhancement of Salmonella invasiveness.None was found to be resistant to tigarcycline,aztreonam,amikacin,cephalosporins and carbapenem and one Salmonella Typhimurium strain was found to be co-resistant to eight classes of antimicrobials at the same time.Resistance genes were generally in accord with relative resistant phenotypes.Conclusion The iNTS strains could show high level multi-drug resistance,indicating that close attention should be paid to the resistance of iNTS though the overall resistance might be relatively not high.