Faculty of Agronomy and Veterinary Medicine, Graduate Program in Bioexperimentation, University of Passo Fundo, BR 285, Passo Fundo, RS 99052-900, Brazil.
Faculty of Agronomy and Veterinary Medicine, Graduate Program in Bioexperimentation, University of Passo Fundo, BR 285, Passo Fundo, RS 99052-900, Brazil.
Int J Food Microbiol. 2022 Oct 16;379:109863. doi: 10.1016/j.ijfoodmicro.2022.109863. Epub 2022 Jul 30.
Salmonella Heidelberg is a clinically-important serovar linked to food-borne illness, and commonly isolated from poultry products. Since 1962, Salmonella Heidelberg has been widely reported from poultry production systems in several countries, including Brazil. The emergence of multidrug-resistant (MDR) Salmonella Heidelberg strains in food animals underscores a significant food safety hazard. In our study, we performed antimicrobial susceptibility testing (AST) and Whole-genome sequencing (WGS) to identify the antimicrobial resistance (AMR) genes, pathogenicity mechanisms and virulence factors (VF) in Salmonella Heidelberg E2 strain recovered from a chicken carcass in Southern Brazil. Salmonella Heidelberg strain belonged to ST15 and showed to be susceptible to colistin (MIC ≤2 μg/mL) and multidrug-resistant to amoxicillin-clavulanic acid, gentamicin, ampicillin, cefaclor, cefazolin, ceftiofur, nalidixic acid, azithromycin, erythromycin, doxycycline, tetracycline and sulfonamide. We identified AMR genes mediating resistance to aminoglycosides (aac(6')-Iaa, aac(3)-VIa, aph(3')-Ia, aadA, 16S rrsD), β-lactams (blaCTX-M-2), quinolones (parC), macrolides (acrB), tetracyclines (tet(A)), fosfomycin (fosA7) and sulfonamide (sul1). Interestingly, the mutation in parC T255S has never been reported among Salmonella Heidelberg strains. To our knowledge, this is the first report of a Salmonella enterica strain harbouring 16S rrsD 471G > A, acrB F28L and acrB L40P chromosomal point mutations. Three plasmid replicon types, ST2-IncHI2, ST2-IncHI2A and IncX1 were identified. Nine Salmonella Pathogenicity Islands and 98 virulence genes encoding virulence factors were identified associated with cell adhesion, invasion, intracellular survival and resistance to antimicrobial peptides. Although Salmonella Heidelberg E2 strain likely originated from poultry, cross-contamination during meat processing cannot be excluded. This study adds to our understanding of Salmonella Heidelberg transmission along the food-chain and informs ongoing regulatory discussions on Salmonella Heidelberg in poultry.
海德堡沙门氏菌是一种与食源性疾病相关的重要临床血清型，通常从家禽产品中分离出来。自 1962 年以来，海德堡沙门氏菌已在包括巴西在内的多个国家的家禽生产系统中广泛报道。食源性动物中出现多药耐药（MDR）海德堡沙门氏菌菌株突出了重大的食品安全隐患。在我们的研究中，我们对从巴西南部鸡胴体中回收的海德堡沙门氏菌 E2 菌株进行了抗菌药物敏感性测试（AST）和全基因组测序（WGS），以鉴定其抗菌药物耐药（AMR）基因、发病机制和毒力因子（VF）。海德堡沙门氏菌菌株属于 ST15，对黏菌素（MIC≤2μg/mL）敏感，对阿莫西林-克拉维酸、庆大霉素、氨苄西林、头孢克洛、头孢唑林、头孢噻呋、萘啶酸、阿奇霉素、红霉素、强力霉素、四环素和磺胺类药物呈多药耐药。我们鉴定出介导氨基糖苷类（aac(6')-Iaa、aac(3)-VIa、aph(3')-Ia、aadA、16S rrsD）、β-内酰胺类（blaCTX-M-2）、喹诺酮类（parC）、大环内酯类（acrB）、四环素类（tet(A））、磷霉素（fosA7）和磺胺类（sul1）耐药的 AMR 基因。有趣的是，沙门氏菌海德堡菌株中从未报道过 parC T255S 的突变。据我们所知，这是首次报道携带 16S rrsD 471G>A、acrB F28L 和 acrB L40P 染色体点突变的肠沙门氏菌菌株。鉴定出三种质粒复制子类型，ST2-IncHI2、ST2-IncHI2A 和 IncX1。确定了 98 个与细胞黏附、侵袭、细胞内存活和抗抗菌肽耐药相关的毒力基因编码的 9 个沙门氏菌致病岛。尽管海德堡沙门氏菌 E2 菌株可能来自家禽，但不能排除在肉类加工过程中的交叉污染。本研究增加了我们对食源性疾病沙门氏菌沿食物链传播的理解，并为正在进行的家禽中沙门氏菌海德堡的监管讨论提供了信息。
