Jorgensen Frieda, Kesby Michelle, Amar Corinne, Rajendram Dunstan, Barker Clare, Crewdson Adam, Painset Anais, Sadler-Reeves Lorraine, Aird Heather, Lai Sandra, Willis Caroline
UK Health Security Agency, Food Water and Environmental Microbiology Laboratory Porton, Porton Down, Salisbury, SP4 0JG, United Kingdom.
UK Health Security Agency, Gastrointestinal Bacteria Reference Unit, National Infection Service, Colindale, London, NW9 5EQ, United Kingdom.
J Appl Microbiol. 2025 Aug 4;136(8). doi: 10.1093/jambio/lxaf192.
A survey to determine the presence of Listeria and indicator bacteria in smoked fish was performed from 2022 to 2023.
Listeria monocytogenes was detected in 3.6% of 783 samples. Listeria monocytogenes was detected more frequently in cold smoked (4.9%) compared to hot smoked (2.0%) samples. The majority (63%) of samples had a water activity that would not prevent the growth of L. monocytogenes. Elevated levels of Enterobacteriaceae (>10 000 CFU g-1) were detected in 4.7% of samples. Listeria monocytogenes was detected more frequently in samples with elevated levels of Enterobacteriaceae. Isolates of L. monocytogenes were compared using whole genome sequencing to historic isolates. Isolates from three samples were the same strain as that associated with a clonal complex (CC) 217 outbreak under investigation and detected despite an earlier product recall. Twelve isolates were CC121 strains and 10 of these belonged to six single nucleotide polymorphism single-linkage clusters with one strain linked to a human case from 2021. One CC415 strain was also linked to a human case. The remaining isolates belonged to CC8, CC9, CC14, CC37, CC31, CC398, CC87, and CC475 with no links to human cases. Investigation of historical isolates revealed that 11 strains were associated with specific manufacturers for up to 10 years. The presence of quaternary ammonium compound efflux genes showed an association with CC.
Diverse L. monocytogenes detected in smoked fish with persistent strains associated with some manufacturing premises. Correlation between presence of L. monocytogenes and high levels of Enterobacteriaceae was detected.
于2022年至2023年开展一项调查，以确定烟熏鱼中是否存在李斯特菌和指示菌。
在783份样本中，3.6%检测出单核细胞增生李斯特菌。与热熏（2.0%）样本相比，冷熏样本（4.9%）中更频繁地检测到单核细胞增生李斯特菌。大多数（63%）样本的水分活度不会抑制单核细胞增生李斯特菌的生长。4.7%的样本中检测到肠杆菌科细菌水平升高（>10 000 CFU g-1）。在肠杆菌科细菌水平升高的样本中更频繁地检测到单核细胞增生李斯特菌。使用全基因组测序将单核细胞增生李斯特菌分离株与历史分离株进行比较。三个样本的分离株与正在调查的克隆复合体（CC）217暴发相关的菌株相同，尽管此前已进行产品召回，但仍被检测到。12株分离株为CC121菌株，其中10株属于六个单核苷酸多态性单连锁簇，有一株与2021年的一例人类病例相关。一株CC415菌株也与一例人类病例相关。其余分离株属于CC8、CC9、CC14、CC37、CC31,、CC398、CC87和CC475，与人类病例无关联。对历史分离株的调查显示，11株菌株与特定制造商有关联，时间长达10年。季铵化合物外排基因的存在与克隆复合体有关联。
在烟熏鱼中检测到多种单核细胞增生李斯特菌，存在与某些生产场所相关的持续性菌株。检测到单核细胞增生李斯特菌的存在与高水平肠杆菌科细菌之间存在相关性。
