Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.
Dipartimento di Medicina Veterinaria, Laboratorio di Ispezione degli Alimenti di Origine Animale, University of Perugia, 06126 Perugia, Italy.
Toxins (Basel). 2019 Jul 19;11(7):424. doi: 10.3390/toxins11070424.
Shiga toxin-producing (STEC) isolates (N = 38) that were incriminated in human disease from 2006 to 2013 in South Africa were characterized by serotype, virulence-associated genes, antimicrobial resistance and pulsed-field gel electrophoresis (PFGE). The isolates belonged to 11 O:H serotypes. STEC O26:H11 (24%) was the most frequent serotype associated with human disease, followed by O111:H8 (16%), O157:H7 (13%) and O117:H7 (13%). The majority of isolates were positive for key virulence-associated genes including (84%), (61%), (68.4%) and (55%), but lacked (29%), (42%), (16%), (16%) and (3%). positive isolates carried (26%) and/or (26%) subtypes All pathogenicity island encoded virulence marker genes were detected in all (100%) isolates except (47%), (84%) and (76%). Multidrug resistance was observed in 89% of isolates. PFGE revealed 34 profiles with eight distinct clusters that shared ≥80% intra-serotype similarity, regardless of the year of isolation. In conclusion, STEC isolates that were implicated in human disease between 2006 and 2013 in South Africa were mainly non-O157 strains which possessed virulence genes and markers commonly associated with STEC strains that have been incriminated in mild to severe human disease worldwide. Improved STEC monitoring and surveillance programs are needed in South Africa to control and prevent STEC disease in humans.
2006 年至 2013 年期间，南非从与人类疾病相关的志贺毒素产生型（STEC）分离株（N=38）中鉴定出 11 种 O:H 血清型。STEC O26：H11（24%）是与人类疾病相关的最常见血清型，其次是 O111：H8（16%）、O157：H7（13%）和 O117：H7（13%）。大多数分离株携带关键毒力相关基因，包括stx1（84%）、stx2（61%）、eae（68.4%）和 tir（55%），但缺乏 ehxA（29%）、vat（42%）、afa/draBC（16%）、aggR（16%）和 espP（3%）。stx1 阳性分离株携带 stx1c（26%）和/或 stx1e（26%）亚型。所有毒力岛编码的毒力标记基因均在所有（100%）分离株中检测到，除了 ehxA（47%）、vat（84%）和 aggR（76%）。89%的分离株表现出多药耐药性。PFGE 显示 34 种谱带，8 个不同的簇具有≥80%的血清内相似性，无论分离年份如何。总之，2006 年至 2013 年期间，南非与人类疾病相关的 STEC 分离株主要是非 O157 株，这些分离株携带与世界各地引起轻度至重度人类疾病的 STEC 株相关的毒力基因和标记。南非需要加强 STEC 监测和监测计划，以控制和预防人类 STEC 疾病。
