Virulence gene profiles: alpha-hemolysin and clonal diversity in Staphylococcus aureus isolates from bovine clinical mastitis in China

Abstract

BackgroundStaphylococcus aureus, a common cause of bovine mastitis, is known for its ability to acquire to antimicrobial resistance and to secrete numerous virulence factors that can exacerbate inflammation. In addition, alpha-hemolysin has an important role in S. aureus infections, diversity of the hla gene (that produces alpha-hmolysin) in S. aureus isolated from bovine mastitis has not been well characterized. The objective was, therefore, to determine diversity of virulence genes, hla gene sequences, and clonal profiles of S. aureus from bovine mastitis in Chinese dairy herds, and to evaluate inter-relationships.ResultsThe antimicrobials resistance varies from as low as 1.9% (2/103) for CTX to as high as 76.7% (79/103) for penicilin in the 103 isolates and 46 (44.7%) S. aureus were determined as multi-resistant isolates with diverse resistance patterns. Thirty-eight virulence gene patterns (with variable frequencies) were identified in the 103 isolates and correlated with MLST types, indicating a great diversity. Although the hla gene also had great diversity (14 genotypes), Hla peptides were relatively more conserved. With 7 clonal complexes identified from 24 spa types and 7 MLST types. Regarding the letter, ST 97 was the dominant type in S. aureus from bovine mastitis in China. Furthermore, based on phylogenetic analysis, there was a distinct evolutionary relationship between the hla gene and MLST.ConclusionMulti-resistant S. aureus occurred in bovine mastitis with diverse resistance patterns. The diversity of virulence gene profiles, especially the hla gene and, their relationship with molecular types were reported for the first time in S. aureus from bovine mastitis, which will be useful for future studies on immunogenicity and vaccine development. In addition, based on the distinct evolutionary relationship between the hla gene and MLST types, we inferred that the hla gene has potential role for molecular typing of S. aureus.Electronic supplementary materialThe online version of this article (10.1186/s12917-018-1374-7) contains supplementary material, which is available to authorized users.

Antimicrobial resistance profiles of 5 common bovine mastitis pathogens in large Chinese dairy herds

“…Resistance of Staph. aureus was lower in our study than previously reported in China (Shi et al, 2010;Wang et al, 2015;Zhang et al, 2018a), whereas resistance data for Staph. aureus were similar to that reported by others (Rajala-Schultz et al, 2004;Güler et al, 2005).…”

Identification of staphylococci causing mastitis in dairy cattle from Algeria and characterization ofStaphylococcus aureus

“…Except for the seb gene that was detected in one isolate (S33). In contrast, Zhang et al () reported that some ST97 isolates had seb, sec and see genes. Meanwhile, Li et al () reported that no enterotoxin gene was present in ST97 isolates.…”

“…Similar results were found in Italy by Magro et al () who reported that clfA , clfB , epbS and vwb genes were harboured by all S. aureus strains isolated from bovine mastitis cases. In China, Zhang et al ( ) reported that more than 85% of S. aureus isolated from bovine mastitis cases harboured clfA , clfB , fnbA , and fnbB genes. However, differences were observed in the prevalence of fnbA and fnbB genes in isolates from Australia, where Gogoi‐Tiwari et al () reported that 54·5% of isolates harboured the fnbA gene and only 1·3% of S. aureus strains harboured the fnbB gene.…”

Staphylococcus aureus Exotoxins and Their Detection in the Dairy Industry and Mastitis

“…Different pathogenic properties require different detection methods, both for disease treatment and for gene identification [2]. To successfully treat this pathogen, it is essential to identify and characterize the virulence gene profiles and the clonal diversity present in S. aureus isolates [24].…”