Salmonellosis is one of the most common foodborne illnesses in the world. The irrational use of antibiotics in medicine and in animal nutrition has greatly favored the emergence and spread of resistant strains of non-typhoid Salmonella. This study aims the determination of the prevalence of Salmonella in bivalve mollusks in Northern Morocco, as well as the molecular typing and antibiotic susceptibility testing of the strains isolated from positive samples. In total, 150 samples from shellfish composed of mussels (Mytilus galloprovincialis), clams (Callista chione and Ruditapes descussatus) and oysters (Magallana gigas). Isolated Salmonella were characterized by Molecular techniques PCR, MLST and MLVA, phylogenetically grouped by MLSA, and susceptibilities were determined for 30 antimicrobial drugs using microdilution method by the BD Phoenix Automated Microbiology System. Prevalence of Salmonella enterica subsp. enterica was 12.67%, grouped in four serovars identified as Chester, Hadar, Typhimurium and Kentucky. Five different MLST STs (sequence types) were detected, ST1954 being the most common, which was mostly found in Chester isolates. Forty-two percent of the isolates showed resistance to more than one antibiotic, especially trimethoprim, sulfa drugs, quinolones and β-lactam. There was a marked change in the serovars and antimicrobial resistance profiles of the Salmonella isolates in this study compared to those in previous studies.

沙门氏菌病是世界上最常见的食源性疾病之一。抗生素在医学和动物营养中的不合理使用极大地促进了非伤寒沙门氏菌耐药菌株的出现和传播。本研究旨在确定摩洛哥北部双壳软体动物中沙门氏菌的流行率，以及从阳性样本中分离出的菌株的分子分型和抗生素敏感性测试。总共有 150 个贝类样本，包括贻贝 ( Mytilus galloprovincialis )、蛤蜊 ( Callista chione和Ruditapes descussatus ) 和牡蛎 ( Magallana gigas )）。分离的沙门氏菌通过分子技术 PCR、MLST 和 MLVA 进行表征，通过 MLSA 进行系统发育分组，并通过 BD Phoenix 自动微生物学系统使用微量稀释方法确定了 30 种抗菌药物的敏感性。肠道沙门氏菌的流行亚种 enterica 为 12.67%，分为四个血清型，分别为 Chester、Hadar、Typhimurium 和 Kentucky。检测到五种不同的 MLST ST（序列类型），ST1954 是最常见的，主要在切斯特分离株中发现。42% 的分离株对一种以上的抗生素表现出耐药性，尤其是甲氧苄啶、磺胺类药物、喹诺酮类和 β-内酰胺类。与之前的研究相比，本研究中沙门氏菌分离株的血清型和抗菌素耐药性发生了显着变化。