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. 2025 Mar 19;25(1):155.
doi: 10.1186/s12866-025-03870-3.

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

Nada H Eidaroos #  1 , Abdelazeem M Algammal #  2 , Walaa Ismail Mohamaden  3 , Asma Massad Alenzi  4   5 , Saad Alghamdi  6 , Ahmed Kabrah  6 , Heba Sayed El-Mahallawy  7 , Hamza M Eid  8 , Alaa Abd Algwad  9 , Samar Ali Asfor  1 , Heinrich Neubauer  10 , Amira A Moawad  11 , Reham M El-Tarabili  1
Affiliations

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

Nada H Eidaroos et al. BMC Microbiol. .

Abstract

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 clfB, clfA, fnbB, fnbA, 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 lukF 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 icaA biofilm genes was 95% in the tested strains. Moreover, 15% of S. aureus strains were MDR to 8 antimicrobial agents and harbored the mecA, ermC, and ermB genes. As well, 12.5% of S. aureus strains were MDR to 8 antimicrobial agents and carried the mecA, ermC, ermB, tetK, and tetM genes. Also, 5% of S. aureus strains were XDR to 11 antimicrobial agents and carried the mecA, ermC, and ermB genes.

Conclusions: The existence of MDR and XDR MRSA strains in bovine milk is a public health hazard. The mecA, ermC, ermB, tetK, and tetM resistance genes and the coa, clfB, eno, icaA, lukF, spa, clfA, 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.

Keywords: agr typing; Biofilm formation; Bovine mastitis; Enterotoxin genes; MDR; MRSA; MSCRAMM region; Virulence genes; XDR.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: This study was accomplished in compliance with the ARRIVE guidelines. All protocols were conducted according to relevant guidelines and regulations. The handling of animals, all experiments, and the collection of milk samples were approved by the Ethics Committee of the Faculty of Veterinary Medicine, Ismailia, Egypt (SCU-VET-REC- 2024037). Moreover, the collection of samples comply the institutional guidelines. The informed consent is not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Biofilm production of the recovered S. aureus isolates from milk
Fig. 2
Fig. 2
agr typing and the distribution of virulence and antimicrobial resistance genes among the retrieved S. aureus isolates
Fig. 3
Fig. 3
a Heatmap showing the distribution of agr typing, multidrug-resistant phenotypes, antimicrobial resistance genes, and virulence genes in the recovered S. aureus isolates from milk. b Twelve clusters are illustrated in a dendrogram
Fig. 4
Fig. 4
The multidrug resistance patterns of the retrieved S. aureus strains from milk
Fig. 5
Fig. 5
Correlation between antibiotic resistance genes and the tested antibiotics
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References

    1. Abutarbush SM. Veterinary Medicine — A Textbook of the Diseases of Cattle, Horses, Sheep, Pigs and Goats, 10th edition. Can Vet J. 2010;51(5):541.
    1. Khairullah A, Ramandinianto S, Effendi M. A Review of Livestock-Associated Methicillin-Resistant Staphylococcus aureus (LA-MRSA) on Bovine Mastitis. Systematic Reviews in Pharmacy. 2020;11:172–83. 10.31838/srp.2020.7.28.
    1. Ruegg P. Managing cows, milking and the environment to minimize mastitis. Japanese Journal of Large Animal Clinics. 2015;5:210-; 10.4190/jjlac.5.210.
    1. Selim A, Kelis K, AlKahtani MDF, Albohairy FM, Attia KA. Prevalence, antimicrobial susceptibilities and risk factors of Methicillin resistant Staphylococcus aureus (MRSA) in dairy bovines. BMC Vet Res. 2022;18(1):293. 10.1186/s12917-022-03389-z. - PMC - PubMed
    1. Tartor YH, Enany ME, Ismail NI, El-Demerdash AS, Eidaroos NH, Algendy RM, et al. Vancomycin-resistant Staphylococcus aureus endangers Egyptian dairy herds. Sci Rep. 2024;14(1):30606. 10.1038/s41598-024-81516-6. - PMC - PubMed

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