Machado Virginia, Pardo Lorena, Cuello Dianna, Giudice Guillermina, Luna Patricia Correa, Varela Gustavo, Camou Teresa, Schelotto Felipe
Universidad de la República, Facultad de Medicina, Instituto de Higiene, Departamento de Bacteriología y Virología, Montevideo, Uruguay.
Departamento de Laboratorios de Salud Pública, Montevideo, Uruguay.
Rev Inst Med Trop Sao Paulo. 2020 Feb 7;62:e5. doi: 10.1590/S1678-9946202062005. eCollection 2020.
The aim of this study was to describe the microbiological characteristics and profile of genes encoding enterotoxins in 95 Staphylococcus aureus isolates obtained between April 2011 and December 2014 from foodstuffs, persons and surfaces of retail food stores. After microbiological identification and antimicrobial susceptibility testing, polymerase chain reactions (PCR) were performed, targeting sea, seb, sec, sed and see genes that code for classical enterotoxins (ET) A-E, and three additional genes: seg , seh and sei , coding for so-called "new enterotoxins" G, H and I. The isolates were characterized by Pulsed Field Gel Electrophoresis (PFGE), and five selected isolates were further analyzed through Multi Locus Sequence Typing (MLST). It is noteworthy that 54.7% of the examined isolates harbored one or more of the investigated ET gene types. Most positive isolates carried more than one ET gene up to five types; seg was the most frequent ET gene, followed by sei. Five enterotoxin-coding isolates also coded for some antimicrobial resistance genes. Two of them, and four additional non-enterotoxic isolates carried erm genes expressing inducible clindamycin resistance. PFGE-types were numerous and diverse, even among enterotoxin-coding strains, because most isolates did not belong to known foodborne outbreaks and the sampling period was long. MLST profiles were also varied, and a new ST 3840 was described within this species. ST 88 and ST 72 enterotoxin-coding isolates have been identified in other regions in association with foodborne outbreaks. This manuscript reports the first systematic investigation of enterotoxin genes in S. aureus isolates obtained from foodstuffs and infected people in Uruguay.
本研究的目的是描述2011年4月至2014年12月期间从零售食品店的食品、人员和表面分离得到的95株金黄色葡萄球菌的微生物学特征及编码肠毒素的基因谱。在进行微生物鉴定和抗菌药物敏感性测试后，进行聚合酶链反应（PCR），靶向编码经典肠毒素（ET）A-E的sea、seb、sec、sed和see基因，以及另外三个基因：编码所谓“新型肠毒素”G、H和I的seg、seh和sei基因。通过脉冲场凝胶电泳（PFGE）对分离株进行分型，对5株选定的分离株进一步通过多位点序列分型（MLST）进行分析。值得注意的是，54.7%的检测分离株携带一种或多种所研究的ET基因类型。大多数阳性分离株携带不止一种ET基因，最多达五种类型；seg是最常见的ET基因，其次是sei。五株编码肠毒素的分离株还编码了一些抗菌耐药基因。其中两株以及另外四株非产肠毒素分离株携带erm基因，表达诱导型克林霉素耐药。即使在产肠毒素菌株中，PFGE型也多种多样，因为大多数分离株不属于已知的食源性暴发，且采样期较长。MLST谱也各不相同，在该菌种内描述了一个新的ST 3840。在其他地区已鉴定出与食源性暴发相关的ST 88和ST 72产肠毒素分离株。本手稿报告了在乌拉圭从食品和感染人群中获得的金黄色葡萄球菌分离株中首次对肠毒素基因进行的系统研究。
