Department of Hygiene, Zoonoses and Animal Behaviour, Faculty of Veterinary Medicine, Suez Canal University, 4.5 Kilo Ring Road St., Ismailia, 41522, Egypt.
Acta Vet Scand. 2022 Jul 29;64(1):17. doi: 10.1186/s13028-022-00637-y.
Salmonella is one of the most common and economically important zoonotic pathogens. This study aimed to determine the occurrence of Salmonella serovars in sheep and goats and their probable zoonotic risk to humans in Suez Canal area in Egypt. A total of 320 fecal samples from sheep (n = 120), goats (n = 100), and humans (n = 100) were collected and examined for the presence of Salmonella based on cultural and biochemical characteristics, and serological analysis. Moreover, the virulence of the identified Salmonella isolates was assessed by molecular screening for invA, stn, spvC, and sopB virulence genes using PCR.
Overall, the occurrence of Salmonella in sheep feces (23.3%) was higher than that in goat feces (7%) and human stool (13%) in the study area. The identified isolates belonged to 12 serotypes; ten, five, and eight from sheep, goats, and humans, respectively. The most frequently identified serotypes were S. Typhimurium from sheep feces, and S. Enteritidis from both goat feces and human stool, with four serotypes; S. Typhimurium, S. Enteritidis, S. Dublin and S. Saintpaul, were mutually shared between all of them. Demographic data revealed that diarrheic sheep (85.7%) and goats (25%) had a higher risk for Salmonella fecal carriage than non-diarrheic ones (19.5% and 6.25%, respectively). The prevalence of Salmonella infection in humans in contact with sheep and goats (28%) was significantly higher than its prevalence in people having a history of contact with animals other than sheep and goats (10%) and those having no history of animal contact (7.3%) (χ = 6.728, P ˂ 0.05). The stn, spvC, and sopB genes were detected in 98.1% of the isolates, with a significant, very strong positive correlation for their mutual presence (P < 0.05). Approximately 40.7% of isolates that carried the invA gene had a non-significant, very weak positive correlation with other virulence genes. The most common genotypic virulence profile for all isolates was stn, spvC, and sopB; however, invA, stn, spvC, and sopB was the frequent virulotype for S. Typhimurium, S. Tsevie, S. Apeyeme, and S. Infantis.
The present study highlights the role of apparently healthy and diarrheic sheep and goats as reservoirs and sources of human infection with virulent Salmonella serovars in the Suez Canal area.
沙门氏菌是最常见和最重要的人畜共患病病原体之一。本研究旨在确定苏伊士运河地区绵羊和山羊中沙门氏菌血清型的发生情况，以及它们对人类可能的人畜共患病风险。从绵羊（n=120）、山羊（n=100）和人类（n=100）中采集了 320 份粪便样本，根据文化和生化特征以及血清学分析，检测沙门氏菌的存在。此外，通过 PCR 对鉴定出的沙门氏菌分离株进行 invA、stn、spvC 和 sopB 毒力基因的分子筛查，评估其毒力。
总的来说，在所研究的地区，绵羊粪便中沙门氏菌的检出率（23.3%）高于山羊粪便（7%）和人类粪便（13%）。鉴定出的分离株属于 12 种血清型；分别来自绵羊、山羊和人类的十种、五种和八种。最常鉴定出的血清型是来自绵羊粪便的鼠伤寒沙门氏菌，来自山羊粪便和人类粪便的肠炎沙门氏菌，四种血清型；鼠伤寒沙门氏菌、肠炎沙门氏菌、都柏林沙门氏菌和圣路易斯沙门氏菌，它们在所有这些中都是相互共享的。人口统计学数据显示，腹泻绵羊（85.7%）和腹泻山羊（25%）比非腹泻绵羊（19.5%）和非腹泻山羊（6.25%）更有可能携带沙门氏菌粪便。与接触绵羊和山羊的人类（28%）相比，与绵羊和山羊以外的动物接触的人类（10%）和没有动物接触史的人类（7.3%）中沙门氏菌感染的患病率显著更高（χ²=6.728，P<0.05）。在 98.1%的分离株中检测到 stn、spvC 和 sopB 基因，它们之间存在显著的、非常强的正相关（P<0.05）。携带 invA 基因的分离株中约有 40.7%与其他毒力基因呈非显著的、非常弱的正相关。所有分离株的最常见基因型毒力谱是 stn、spvC 和 sopB；然而，invA、stn、spvC 和 sopB 是鼠伤寒沙门氏菌、Tsevie 沙门氏菌、Apeyeme 沙门氏菌和 Infantis 沙门氏菌的常见毒力型。
本研究强调了貌似健康和腹泻的绵羊和山羊作为苏伊士运河地区人类感染强毒力沙门氏菌血清型的储存宿主和传染源的作用。
