Assessment of the prevalence of Streptococcus uberis in dairy cow feces and implications for herd health

Abstract

Streptococcus uberis is a major causative agent of bovine mastitis worldwide, negatively affecting both milk production and animal welfare. Mammary infections result from environmental reservoirs, with cattle themselves required to propagate the infection cycle. Two longitudinal studies were performed to investigate the prevalence of Streptococcus uberis within feces and to evaluate factors which may affect gastrointestinal carriage. Bacterial detection was confirmed using a PCR-based method directed against sub0888 that detected S. uberis at an analytical sensitivity of 12 cfu/g of bovine feces. The first study sampled an entire herd at 8-wk intervals, over a 10-mo period and identified that maintenance of S. uberis within the dairy cow environment was due to a high proportion of animals shedding S. uberis and not due to a low number of "super-shedding" cows within the herd. Seasonality influenced detection rates, with detection levels significantly higher for housed cattle compared with those at pasture. Multilevel logistic regression was used to identify significant factors that affected S. uberis detection; these included parity, stage of lactation, and body condition score. An additional study involved screening a smaller cohort of cows housed over a 4-wk period and identified an increased probability of detection if cows were housed in loose straw yards, compared those in straw cubicles. This study highlighted several cow and management related factors that affect both detection of S. uberis and future infection risks.

Genomic surveillance reveals antibiotic resistance gene transmission via phage recombinases within sheep mastitis-associated Streptococcus uberis

“…1 ). This data is consistent with dairy animals being opportunistically colonised by environmental [ 7 , 8 ] or gastrointestinal carriage of S. uberis [ 21 ].…”

In silico analysis of virulence factors of Streptococcus uberis for a chimeric vaccine design

“…S . uberis has been identified as one of the most prevalent environmental infectious agents in several countries, despite the fact that multiple bacterial species can cause bovine mastitis (Sherwin et al 2021 ; Sherwin and Breen 2022 ). The transmission of S .…”

Streptococcus ruminantium-associated sheep mastitis outbreak detected in Italy is distinct from bovine isolates

“…Future genomic sequencing of clinical isolates is recommended so that a greater number of genomes can be used to improve future genomic understanding of this under-represented but relevant agricultural pathogen. Short-term but frequent gastrointestinal colonisation and faecal shedding by the closely related S. uberis has been demonstrated [50] and it is possible that S. ruminantium follows a similar strategy. Therefore, we recommend molecular and/or genomic surveillance of non-clinical (healthy) host gastrointestinal tracts to determine non-clinical carriage rates, which would help to determine ock/herd susceptibility and allow early intervention to prevent disease onset, while ock outbreaks could be prevented by isolation of positive hosts.…”