Persistent contamination of raw milk by Campylobacter jejuni ST-883

Abstract

Campylobacter jejuni has caused several campylobacteriosis outbreaks via raw milk consumption. This study reports follow-up of a milk-borne campylobacteriosis outbreak that revealed persistent C. jejuni contamination of bulk tank milk for seven months or longer. Only the outbreak-causing strain, representing sequence type (ST) 883, was isolated from milk, although other C. jejuni STs were also isolated from the farm. We hypothesized that the outbreak strain harbors features that aid its environmental transmission or survival in milk. To identify such phenotypic features, the outbreak strain was characterized for survival in refrigerated raw milk and in aerobic broth culture by plate counting and for biofilm formation on microplates by crystal violet staining and quantification. Furthermore, whole-genome sequences were studied for such genotypic features. For comparison, we characterized isolates representing other STs from the same farm and an ST-883 isolate that persisted on another dairy farm, but was not isolated from bulk tank milk. With high inocula (10 5 CFU/ml), ST-883 strains survived in refrigerated raw milk longer (4-6 days) than the other strains (�3 days), but the outbreak strain showed no outperformance among ST-883 strains. This suggests that ST-883 strains may share features that aid their survival in milk, but other mechanisms are required for persistence in milk. No correlation was observed between survival in refrigerated milk and aerotolerance. The outbreak strain formed a biofilm, offering a potential explanation for persistence in milk. Whether biofilm formation was affected by pTet-like genomic element and phase-variable genes encoding capsular methyltransferase and cytochrome C551 peroxidase warrants further study. This study suggests a phenotypic target candidate for interventions and genetic markers for the phenotype, which should be investigated further with the final aim of developing control strategies against C. jejuni infections.

Investigating Major Recurring Campylobacter jejuni Lineages in Luxembourg Using Four Core or Whole Genome Sequencing Typing Schemes

“…Thus, the question of the environmental transmission routes arises, particularly concerning animal reservoirs such as poultry and ruminants that could contribute to water contamination (Mughini-Gras et al, 2016). Persistent strains have already been identified, mainly in poultry farms and in milk, and it would be interesting to link lineage A with other contamination sources such as insects, rodents, drinking water, or the surrounding environment (Kudirkienėet al, 2010;Perez-Boto et al, 2012;Rauber-Würfel et al, 2019;Jaakkonen et al, 2020). The lineage B (ST2254-gyrA9-porA1) arose unexpectedly from our national surveillance with an epidemic curve between March and April 2014 (>70 campylobacteriosis cases).…”

High Prevalence of Intestinal Pathogens in Indigenous in Colombia

“…Chicken/poultry are the most common animals distributed within Wiwa communities. The consumption of raw milk might also contribute to the high number of infections [ 34 ].…”

Evaluation of culture‐based and molecular detection methods for Campylobacter in New Zealand raw cows’ milk

“…Consistent with this, C.jejuni isolates from raw milk samples were recently shown to have prolonged survival in raw milk compared with isolates from other farm sources (Jaakkonen et al . 2020).…”

“…A reduction in viability from ~0·5 to >3 log 10 CFU per ml was observed for some dairy‐associated C. jejuni isolates incubated for 24 h in refrigerated raw milk (Jaakkonen et al . 2020). Cells might also potentially have entered into a VBNC state, although to our knowledge, a VBNC state has not been demonstrated in milk.…”