肠道沙门菌是一种重要的食源性致病菌,对人体健康构成重大危害。耐抗生素沙门氏菌的出现和恶化已引起全世界的广泛关注。对整个食物链中的抗生素抗性食源性病原体进行风险评估是确保食品安全的迫切要求。增长,生存能力,抗生素耐药沙门氏菌的毒力代表了至关重要的生物学特性,在微生物风险评估中起着重要作用。在这项研究中,用氨苄西林(Amp)和环丙沙星(CIP)诱导了8株抗生素敏感的肠球菌,分别,并获得了AMP抗性和CIP抗性突变体。不同温度(25、30、35℃)下的生长特性,暴露于热(55、57.5、60°C)和酸(HCl,pH=3.0),毒力潜力(对Caco-2细胞的粘附和侵袭,生物膜的形成和运动性)和模型物种(Galleriamellonella)中的致死率进行了评估,并比较了抗生素暴露前后的肠球菌菌株。AMP和CIP的诱导可能会促进对其抗生素类别的交叉抗生素耐药性,β-内酰胺类和喹诺酮类,以及一些复合抗生素。观察到抗生素诱导抗性菌株通常表现出降低的生长能力和较低的耐热性,尽管在所有测试条件下差异均不显著。AMP抗性菌株的耐酸性明显低于敏感菌株和CIP抗性菌株,同时表现出增强的生物膜形成能力。总的来说,抗生素诱导的抗性没有显著影响运动性,坚持,或Caco-2细胞的侵袭能力。然而,CIP耐药菌株在G.melonella感染中显示出较低的致死率,而AMP抗性菌株没有,甚至两个菌株提高了杀伤力。对抗生素抗性肠球菌的生物学特性的研究对于更好地了解微生物对食物链和人类健康的风险至关重要。从而促进更准确的风险评估。
Salmonella enterica is an important foodborne pathogen that constitutes a major health hazard. The emergence and aggravation of antibiotic-resistant Salmonella has drawn attention widely around the world. Conducting a risk assessment of antibiotic-resistant foodborne pathogens throughout the food chain is a pressing requirement for ensuring food safety. The growth, survival capability, and virulence of antibiotic-resistant Salmonella represent crucial biological characteristics that play an important role in microbial risk assessment. In this study, eight antibiotic-sensitive S. enterica strains were induced by Ampicillin (Amp) and Ciprofloxacin (CIP), respectively, and AMP-resistant and CIP-resistant mutants were obtained. The growth characteristics under different temperatures (25, 30, 35 °C), viability after exposure to heat (55, 57.5, 60 °C) and acid (HCl, pH = 3.0), the virulence potential (adhesion and invasion to Caco-2 cells, biofilm formation and motility) and the lethality in a model species (Galleria mellonella) were evaluated and compared for S. enterica strains before and after antibiotic exposure. The induction by AMP and CIP are likely to promote cross-antibiotic resistance to their antibiotic classes, β-lactams and quinolones, as well as some compound antibiotics. It was observed that generally the antibiotic-induction-resistant strains showed decreased growth ability and lower heat resistance, although the differences were not significant at all the conditions tested. The AMP-resistant strains were significantly less acid resistance than the sensitive and the CIP-resistant ones, while exhibiting increased biofilm formation ability. In general, the antibiotic-induced resistance did not significantly affect the motility, adherence, or invasion ability of Caco-2 cells. However, CIP-resistant strains displayed lower lethality in G. mellonella infection, whereas AMP-resistant strains did not, and even two strains improved lethality. The study of the biological characteristics of antibiotic-resistant S. enterica is essential in better understanding the microbial risks to both the food chain and human health, thereby facilitating a more accurate risk assessment.