Study of the efficacy of a Streptococcus uberis mastitis vaccine against an experimental intramammary infection with a heterologous strain in dairy cows

Abstract

Streptococcus uberis is a worldwide pathogen that causes intramammary infections in dairy cattle. Nevertheless, commercial vaccines are currently not available and measures to control S. uberis mastitis are limited to the implementation of good management practices. The aim of the present study was to evaluate the efficacy of an S. uberis subunit vaccine against bovine mastitis (Laboratorios Hipra S.A., Amer, Spain) administered precalving against an experimental intramammary challenge with a heterologous S. uberis strain in dairy cows postcalving. With this objective, 25 gestating Holstein-Friesian heifers were randomly assigned to 1 of 2 groups: group 1 (n = 13), vaccinated by intramuscular route with the vaccine, and group 2 (n = 12), vaccinated by intramuscular route with phosphate-buffered saline as a control group. Both groups were immunized 60 and 21 d before the expected parturition date (75 and 36 d before challenge). Fourteen days after calving all cows were challenged by intramammary infusion of 100 colony-forming units of a heterologous S. uberis strain in 2 quarters per cow. Then, challenged quarters were monitored for clinical signs of mastitis, bacterial count, and somatic cell count for the following 21 d. Rectal temperature and daily milk yield per cow were also assessed. Results showed that all challenged quarters developed clinical mastitis. Nevertheless, vaccination significantly reduced the clinical signs of mastitis, bacterial count, rectal temperature, and daily milk yield losses after the intramammary infection and significantly increased the number of quarters with no bacterial isolation and somatic cell count <200,000 cells/mL at the end of the study (d 19, 20, and 21 after challenge). To confirm the efficacy of this vaccine, further studies under field conditions are needed.

Symposium review: Intramammary infections—Major pathogens and strain-associated complexity

“…Challenge of vaccinated cows with a heterologous strain of Strep. uberis showed that vaccination did not prevent infection but reduced clinical mastitis signs, bacterial count in milk, and milk yield (Collado et al, 2018). This vaccine requires the administration of 3 doses yet does not induce long-lasting immunity (https: / / www .ema .europa .eu/ documents/ product -information/ ubac -epar -product -information _en .pdf).…”

Technical note: Development of multiplex PCR assays for the molecular characterization of Streptococcus uberis strains isolated from bovine mastitis

“…It has been estimated that Strep. uberis is responsible for 14 to 26% of clinical mastitis cases in Canada, the United States, and the Netherlands, and it is the main cause of clinical mastitis in New Zealand and Australia (Collado et al, 2018). It has also been identified as being responsible for a large part of clinical mastitis in several European countries such as Belgium, Germany, Italy, and the UK (Bradley et al, 2007;Krömker et al, 2014).…”

In Vitro Susceptibility of Mastitis Pathogens Isolated from Clinical Mastitis Cases on Northern German Dairy Farms

“…In several trials, the application of vaccines was able to cause a reduced severity of the clinical signs accompanied with mastitis cases caused by S. uberis and E. coli [43,44]. Furthermore, S. uberis-specific vaccines were beneficial concerning the reduction in somatic cell count and bacterial count [44]. While Schukken et al (2014) achieved a reduction in both the incidence and prevalence of intramammary infections with staphylococci [45], previous observations by Tenhagen et al (2001) were contrary.…”

“…Another possibility for avoiding the extensive use of antimicrobials could be the application of vaccines. In several trials, the application of vaccines was able to cause a reduced severity of the clinical signs accompanied with mastitis cases caused by S. uberis and E. coli [43,44]. Furthermore, S. uberis-specific vaccines were beneficial concerning the reduction in somatic cell count and bacterial count [44].…”