Molecular epidemiology of Streptococcus agalactiae isolated from mastitis in Brazilian dairy herds

Abstract

Streptococcus agalactiae is one of the most common pathogens leading to mastitis in dairy herds worldwide; consequently, the pathogen causes major economic losses for affected farmers. In this study, multilocus sequence typing (MLST), genotypic capsular typing by multiplex polymerase chain reaction (PCR), and virulence gene detection were performed to address the molecular epidemiology of 59 bovine (mastitis) S. agalactiae isolates from 36 dairy farms located in the largest milk-producing mesoregions in Brazil (Minas Gerais, São Paulo, Paraná, and Pernambuco). We screened for the virulence genes bac, bca, bibA, cfb, hylB, fbsA, fbsB, PI-1, PI-2a, and PI-2b, which are associated with adhesion, invasion, tissue damage, and/or immune evasion. Furthermore, five capsular types were identified (Ia, Ib, II, III, and IV), and a few isolates were classified as non-typeable (NT). MLST revealed the following eight sequence types (STs): ST-61, ST-67, ST-103, ST-146, ST-226, ST-314, and ST-570, which were clustered in five clonal complexes (CC64, CC67, CC103, CC17, and CC314), and one singleton, ST-91. Among the virulence genes screened in this study, PI-2b, fbsB, cfb, and hylB appear to be the most important during mastitis development in cattle. Collectively, these results establish the molecular epidemiology of S. agalactiae isolated from cows in Brazilian herds. We believe that the data presented here provide a foundation for future research aimed at developing and implementing new preventative and treatment options for mastitis caused by S. agalactiae.

Investigation ofStreptococcus agalactiaeusingpcsB‐based LAMP in milk, tilapia and vaginal swabs in Haikou, China

“…We demonstrated that the bac gene was absent in the four human GBS isolates. Similar results were observed for GBS isolates causing mastitis in Brazilian dairy herds, irrespective of their serotypes (Ib, Ia or II) (Carvalho‐Castro et al ). Given the small sample sizes involved, the fact that only GBS strains of serotypes Ib, Ia and II were detected in both populations may have been a coincidence.…”

Biofilm formation on different pH conditions byStreptococcus agalactiaeisolated from bovine mastitic milk

“…; Carvalho‐Castro et al . ). Although they are available in a very short time in the environment, S. agalactiae survives inside the mammary gland for a long time (Kefee ).…”

“…Genetic diversity and clonal relatedness of S. agalactiae strains recovered from human and animal infections have been previously demonstrated by pulsed-field gel electrophoresis (PFGE) (Pinto et al 2013). Studies performed in different countries showed capsular types Ia, II, III, IV and V predominant in human and bovine infections, including Brazil (Pinto et al 2013;Carvalho-Castro et al 2017;Pang et al 2017).…”

“…Streptococcus agalactiae causes clinical and subclinical contagious bovine mastitis, a major problem for the dairy industry. Consequently, the disease may cause significant economic loss due to decreased production and milk quality, increased use of medicaments and veterinary fees (Gomes et al 2016;Carvalho-Castro et al 2017). Although they are available in a very short time in the environment, S. agalactiae survives inside the mammary gland for a long time (Kefee 1997).…”

Microevolution of aquaticStreptococcus agalactiaeST-261 from Australia indicates dissemination via imported tilapia and ongoing adaptation to marine hosts or environment

“…In GBS, capsular serotyping either with antibodies or by ‘molecular serotyping’ (sequencing of the capsular operon) has become a widely used method of typing for population studies (17–20) and, currently, S . agalactiae can be divided into ten capsular serotypes (Ia, Ib and II-IX) (18, 21). Determining capsular serotypes is also critical for vaccine formulation since CPS is highly immunogenic and can confer excellent protection against infections by the homologous CPS serotype (20, 22, 23).…”