a Department of Clinical Microbiology , Christian Medical College and Hospital , Vellore , India.
Pathog Glob Health. 2019 Feb;113(1):20-26. doi: 10.1080/20477724.2019.1574112. Epub 2019 Feb 6.
Non-typhoidal Salmonella (NTS) are foodborne pathogens that are responsible for self-limiting gastroenteritis in humans. The present study aims at the molecular characterisation and comparative genomics of Salmonella enterica serovar Senftenberg strain P5558 isolated from the pus samples of a patient suffering from stump infection. The isolate was subjected to serotyping and antimicrobial susceptibility test to understand the phenotypical characteristics. Whole genome sequencing (WGS) was carried out and comparative genomics using computational tools showed the antimicrobial resistance and virulence gene profile of the isolates from the genome sequence data. Typing experiments confirmed that the isolate belong to S. Senftenberg with sequence type ST14. Resistance against β-lactams is associated with the presence of bla, bla, bla and bla genes. Similarly resistance to aminoglycoside was associated with five aminoglycoside modifying enzymes aac(6')-Ia, aac(6')-Ib, aph(3')-Ib, aph(6')-Ib and ant(3'')-Ia, sulfonamide with sul-1 and sul-2 and chloramphenicol with florR gene. Substitutions in gyrA (S83Y, D87G) and parC (S80I) genes found to be the reason for fluoroquinolone resistance. The plasmid profiling showed the isolate has four resistance plasmids in which plasmid p5558-NDM (IncA/C) harbours major resistance genes including bla and bla Determination of virulence gene profile revealed that the genome carries all major Salmonella pathogenicity islands and virulence factors. From our findings it is clear that the isolate possess characteristic pathogenicity islands (SPI 1-6, 13, 14), major virulence factors and acquired resistance genes. Comparative analysis suggests the evolution and distribution of the MDR gene encoding plasmids in NTS.
非伤寒沙门氏菌（NTS）是食源性病原体，可导致人类出现自限性胃肠炎。本研究旨在对从患有残端感染的患者脓液样本中分离到的肠炎沙门氏菌血清型森夫滕贝格 P5558 菌株进行分子特征分析和比较基因组学研究。该分离株进行了血清型鉴定和药敏试验，以了解其表型特征。进行了全基因组测序（WGS），并使用计算工具进行比较基因组学分析，从基因组序列数据中显示了分离株的抗微生物药物耐药性和毒力基因谱。分型实验证实该分离株属于 S. Senftenberg，序列型为 ST14。对β-内酰胺类药物的耐药性与 bla、bla、bla 和 bla 基因的存在有关。同样，对氨基糖苷类药物的耐药性与 5 种氨基糖苷类修饰酶 aac(6')-Ia、aac(6')-Ib、aph(3')-Ib、aph(6')-Ib 和 ant(3'')-Ia、磺胺类与 sul-1 和 sul-2 以及氯霉素与 florR 基因有关。gyrA（S83Y、D87G）和 parC（S80I）基因的取代被认为是氟喹诺酮类药物耐药的原因。质粒谱分析表明，该分离株有 4 个耐药质粒，其中质粒 p5558-NDM（IncA/C）携带主要耐药基因，包括 bla 和 bla。毒力基因谱的测定表明，基因组携带所有主要的沙门氏菌致病性岛和毒力因子。从我们的研究结果可以清楚地看出，该分离株具有特征性的致病性岛（SPI 1-6、13、14）、主要毒力因子和获得性耐药基因。比较分析表明，NTS 中编码 MDR 基因的质粒的进化和分布。
