Journal Article

Virulence traits, agr typing, multidrug resistance patterns, and biofilm ability of MDR Staphylococcus aureus recovered from clinical and subclinical mastitis in dairy cows

Eidaroos, Nada H., Asfor, Samar Ali, Kabrah, Ahmed, Moawad, Amira A., Algammal, Abdelazeem M., Algwad, Alaa Abd, Mohamaden, Walaa Ismail, El-Mahallawy, Heba Sayed, Alghamdi, Saad, El-Tarabili, Reham M., Neubauer, Heinrich, Alenzi, Asma Massad, Eid, Hamza M.

2025

Overview

Background Bovine mastitis caused by Staphylococcus aureus is considered a public health threat globally. Herein, we aimed to investigate the occurrence, agr typing, antimicrobial resistance patterns, biofilm production, and PCR-based detection of the virulence, biofilm, adhesion, and enterotoxins genes of S. aureus strains recovered from clinical and subclinical bovine mastitis. Results The prevalence of S. aureus in the examined milk samples was 44.4%. Besides, 95% of the retrieved S. aureus strains were identified as MRSA. Herein, all the tested isolates were biofilm producers. PCR revealed that 85% of the retrieved S. aureus strains were positive for the agr I gene. Furthermore, the clf B, clf A, fnb B, fnb A, and cna genes were detected with a prevalence of 100%, 80%, 60%, 55%, and 30%, respectively. Also, all the tested S. aureus strains were positive for the coa gene (100%). Besides, 92.5% and 85% of the recovered strains harbored the luk F and spa genes, respectively. In addition, the prevalence of the hla , hlb , and hlg hemolysin genes was 70%, 50%, and 35%, respectively. Among the enterotoxin genes, the seb gene was detected in 30% of the tested strains. The prevalence of eno and ica A biofilm genes was 95% in the tested strains. Moreover, 15% of S. aureus strains were MDR to 8 antimicrobial agents and harbored the  mec A, erm C, and erm B genes. As well, 12.5% of S. aureus strains were MDR to 8 antimicrobial agents and carried the mec A, erm C, erm B, tet K, and tet M genes. Also, 5% of S. aureus strains were XDR to 11 antimicrobial agents and carried the  mec A, erm C, and erm B genes. Conclusions The existence of MDR and XDR MRSA strains in bovine milk is a public health hazard. The mec A, erm C, erm B, tet K, and tet M resistance genes and the coa, clf B, eno, ica A, lukF , spa , clf A, and hla virulence genes are commonly associated with the MDR and XDR MRSA strains. Moreover, the seb gene was the predominant enterotoxin gene in the MRSA strains recovered from milk.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: agr typing / Analysis / Animals / Anti-Bacterial Agents - pharmacology / Antibiotics / Antimicrobial agents / Antimicrobial resistance / Bacteria / Bacterial Proteins - genetics / Biofilms / Biofilms - growth & development / Biological Microscopy / Biomedical and Life Sciences / Bovine mastitis / Care and treatment / Cattle / Complications and side effects / Cow's milk / Dairy cattle / Dairy industry / Diagnosis / Diseases / Drug resistance / Drug resistance in microorganisms / Drug Resistance, Multiple, Bacterial - genetics / Enterotoxins / Enterotoxins - genetics / Female / Genes / Genetic aspects / Growth / Health hazards / Health risks / Immune system / Life Sciences / Mastitis / Mastitis, Bovine - microbiology / MDR / Microbial Sensitivity Tests / Microbiology / Milk / Milk - microbiology / MRSA / Multidrug resistance / Mycology / Parasitology / Pathogenesis / Pathogens / Prevention / Proteins / Public health / R&D / Research & development / Risk factors / Spas / Staphylococcal Infections - microbiology / Staphylococcal Infections - veterinary / Staphylococcus aureus / Staphylococcus aureus - drug effects / Staphylococcus aureus - genetics / Staphylococcus aureus - isolation & purification / Staphylococcus aureus - pathogenicity / Staphylococcus aureus - physiology / Staphylococcus aureus infections / Staphylococcus infections / Tissue typing / Toxins / Trans-Activators - genetics / Virology / Virulence / Virulence (Microbiology) / Virulence - genetics / Virulence Factors - genetics / Virulence genes / XDR