Longitudinal study of the occurrence, persistence and contamination routes of Listeria monocytogenes genotypes on three Finnish dairy cattle farms.

Longitudinal study of the occurrence, persistence and contamination routes of Listeria monocytogenes genotypes on three Finnish dairy cattle farms. Appl Environ Microbiol. 2017 Dec 08;: Authors: Castro H, Jaakkonen A, Hakkinen M, Korkeala H, Lindström M Abstract The molecular epidemiology of Listeria monocytogenes was investigated in a longitudinal study of three Finnish dairy farms during 2013 -- 2016. Totals of 186 bulk tank milk (BTM) samples, 224 milk filter socks (MFS), and 1702 samples of the barn environment were analyzed and isolates of L. monocytogenes were genotyped using pulsed-field gel electrophoresis. L. monocytogenes occurred throughout the year in all sample types, and the prevalence in MFS increased significantly during the indoor season. L. monocytogenes was more prevalent in MFS (29%) than in BTM samples (13%). However, the prevalence of L. monocytogenes varied more between farms in samples of MFS (13--48%) than BTM (10--16%). For each farm, the L. monocytogenes genotypes detected were classified by persistence (persistent if isolated from ≥3 samples during ≥6 months) and predominance (predominant if >5% prevalence on at least one farm visit). The prevalence of sporadic genotypes was 4--5% on all three farms. In contrast, the prevalence of persistent predominant genotypes varied between farms from 4% to 16%. The highest prevalence of persistent predominant genotypes was observed on the farm with the poorest...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research