单核细胞增生李斯特菌是一种重要的食源性致病菌,在全球范围内流行。了解不同亚型菌株之间潜在致病性的变异性对于风险评估至关重要。在这项研究中,增长,生存,对从中国进口肉类中分离的16株(2018-2020年)单核细胞增生李斯特菌的毒力特征进行了研究。使用检测时间(TTD)方法和Baranyi模型在不同温度(25、30和37°C)下评估了最大比生长速率(μmax)和滞后期(λ)。生存特征通过暴露于热(60、62.5和65°C)和酸(HCl,pH=2.5、3.5和4.5)。通过对Caco-2细胞的粘附和侵袭来评估潜在的毒力,运动性,以及对MellonellaGalleriaMellonella的杀伤力。在不同谱系和亚型的菌株之间比较了潜在的致病性。结果表明,在三个生长温度下,谱系I菌株表现出比谱系II菌株更高的生长速率,特别是谱系I中的血清型4b,在所有测试温度下,血清型1/2a和1/2b始终显示出比其他亚型更高的耐热性。在pH2.5、3.5和4.5下,在谱系I和谱系II菌株之间没有观察到对数减少的显著差异。然而,血清型1/2c菌株在pH2.5时表现出显着的低耐酸性。在毒力方面,谱系I菌株优于谱系II菌株。血清型4b菌株对Caco-2细胞的侵袭率和对G.mellonella的致死率高于其他血清型。这项研究为增长提供了有意义的见解,生存,和单核细胞增生李斯特菌的毒力,为了解单核细胞增生李斯特菌的致病性和亚型之间的相关性提供有价值的信息。
Listeria monocytogenes is an important foodborne pathogen with worldwide prevalence. Understanding the variability in the potential pathogenicity among strains of different subtypes is crucial for risk assessment. In this study, the growth, survival, and virulence characteristics of 16 L. monocytogenes strains isolated from imported meat in
China (2018-2020) were investigated. The maximum specific growth rate (μmax) and lag phase (λ) were evaluated using the time-to-detection (TTD) method and the Baranyi model at different temperatures (25, 30, and 37 °C). Survival characteristics were determined by D-values and population reduction after exposure to heat (60, 62.5, and 65 °C) and acid (HCl, pH = 2.5, 3.5, and 4.5). The potential virulence was evaluated via adhesion and invasion to Caco-2 cells, motility, and lethality to Galleria mellonella. The potential pathogenicity was compared among strains of different lineages and subtypes. The results indicate that the lineage I strains exhibited a higher growth rate than the lineage II strains at three growth temperatures, particularly serotype 4b within lineage I. At all temperatures tested, serotypes 1/2a and 1/2b consistently demonstrated higher heat resistance than the other subtypes. No significant differences in the log reduction were observed between the lineage I and lineage II strains at pH 2.5, 3.5, and 4.5. However, the serotype 1/2c strains exhibited significantly low acid resistance at pH 2.5. In terms of virulence, the lineage I strains outperformed the lineage II strains. The invasion rate to Caco-2 cells and lethality to G. mellonella exhibited by the serotype 4b strains were higher than those observed in the other serotypes. This study provides meaningful insights into the growth, survival, and virulence of L. monocytogenes, offering valuable information for understanding the correlation between the pathogenicity and subtypes of L. monocytogenes.