Veterinary Research Forum
Vet Res Forum

Prevalence and molecular characterization of resistant Staphylococcus aureus strains in bulk milk tanks of dairy cattle in Northern Egypt

Document Type : Original Article

Authors

Walaa Abdallah Gad 1
Salama Ahmed Osman 2
Khaled Abd El-Hamid Abd El-Razik 1
Ashraf Hassan Soror 1
Yousef Adel Soliman 3
Ehab Ali Fouad 4

1 Department of Animal Reproduction, Veterinary Research Institute, National Research Center, Cairo, Egypt

2 Department of Animal Medicine, Faculty of Veterinary Medicine, Kafrelsheikh University, Kafr El-Sheikh, Egypt

3 Central Lab for Evaluation of Veterinary Biologics (CLEVB), Cairo, Egypt

4 Department of Zoonosis, Veterinary Research Institute, National Research Center, Cairo, Egypt

https://doi.org/10.30466/vrf.2024.2038109.4398
Abstract
Bovine subclinical mastitis represents a major cause of severe economic losses in dairy farms. This research aimed to detect the antimicrobial resistance trends of Staphylococcus aureus and to determine the presence of mecA, mphC, lnuA, tetK and tetL antimicrobial resistance genes in raw bulk milk in the period between December 2023 and February 2024. One hundred raw bulk cow milk samples were gathered from different dairy farms in Egypt. The prevalence of subclinical bovine mastitis was 65.00% using California mastitis test. The prevalence of isolated S. aureus was 46.15% via bacterial culturing and all isolates (n = 30) were confirmed via hemolytic activity, catalase and coagulase test, and gram staining followed by polymerase chain reaction targeting nuc1 gene. Antimicrobial sensitivity test was applied on all confirmed S. aureus isolates utilizing the disk diffusion method on Mueller-Hinton agar. The highest resistance was verified for tetracycline at 100% followed by erythromycin and clindamycin at 56.66 and 16.66%, respectively. The highest sensitivity at 100% was verified for amikacin, ampicillin, amoxicillin plus clavulanic acid, ampicillin plus sulbactam, ciprofloxacin, colistin, gentamicin, imipenem, tobramycin, doxycycline and vancomycin. Multidrug resistance was found in 20.00% of the total isolates. Methicillin resistant S. aureus represented by mecA gene was identified in 83.33% of isolates. Macrolides resis­tant S. aureus represented by mphC gene was identified in 16.66% of isolates. Lincosamide resistant S. aureus represented by inuA gene was identified in 66.66% of isolates. Tetracycline resistant S. aureus represented by tetK and tetL genes was detected in 23.33 and 53.33% of isolates, respectively. This study provided antibiotic-resistant S. aureus profiles to dairy farms to avoid treatment failure, adverse effects on animal health and economic impact for the owner of the animal.

Keywords

Antibiotic resistance genes
Antimicrobial sensitivity test
Bovine mastitis
Staphylococcus aureus

Subjects

  1. Gad WA, Osman SA, Hegazy YM, et al. Diagnosis of subclinical staphylococcal aureus bovine mastitis using nanotechnology-based techniques. Egypt J Vet Sci 2025; 56(4): 721-730.
  2. Rahman MH, El Zowalaty ME, Falgenhauer L, et al. Molecular identification and whole genome sequence analyses of methicillin-resistant and mastitis-associated Staphylococcus aureus sequence types 6 and 2454 isolated from dairy cows. J Genomics 2024; 12: 19-25.
  3. Lubna, Hussain T, Shami A, et al. Antimicrobial usage and detection of multidrug-resistant Staphylococcus aureus: methicillin-and tetracycline-resistant strains in raw milk of lactating dairy cattle. Antibiotics 2023; 12(4): 673. doi: 10.3390/antibiotics12040673.
  4. Jones GM. Milking practices recommended to assure milk quality and prevent mastitis. Available at: https:// www.thecattlesite.com/articles/714/milking-practices -recommended-to-assure-milk-quality-and-prevent-mastitis. Accessed March 27, 2025.‏
  5. Algammal AM, Enany ME, El-Tarabili RM, et al. Prevalence, antimicrobial resistance profiles, virulence and enterotoxins-determinant genes of MRSA isolated from subclinical bovine mastitis in Egypt. Pathogens 2020; 9(5): 362. doi: 10.3390/pathogens9050362.
  6. Brahma U, Suresh A, Murthy S, et al. Antibiotic resistance and molecular profiling of the clinical isolates of Staphylococcus aureus causing bovine mastitis from India. Microorganisms 2022; 10(4): 833. doi: 10.3390/microorganisms10040833.
  7. Nesma HY, Nagah MH, Halawa MA, et al. Influence of some hygienic measures on the prevalence of subclinical mastitis in a dairy farm. Int J Dairy Sci 2020; 15(1): 38-47.
  8. Khasapane NG, Koos M, Nkhebenyane SJ, et al. Detection of Staphylococcus isolates and their antimicrobial resistance profiles and virulence genes from subclinical mastitis cattle milk using MALDI-TOF Ms, PCR and sequencing in free State Province, South Africa. Animals 2024; 14(1): 154. doi: 10.3390/ ani14010154.
  9. Rahim AH, Ahmad G, Ijaz M, et al. Isolation and identification of antibiotics susceptible Staph aureus from unprocessed milk. J Clin Med Res 2021; 3(2): 1-11.
  10. Wehr HM, Frank Standard methods for the examination of dairy products. Available at: https://ajph.aphapublications.org/doi/book/10.2105/9780875530024. Accessed March 27, 2025.
  11. Lina G, Quaglia A, Reverdy ME, et al. Distribution of genes encoding resistance to macrolides, lincosamides, and streptogramins among staphylococci. Antimicrob Agents Chemother 1999; 43(5): 1062-1066.
  12. Strommenger B, Kettlitz C, Werner G, et al. Multiplex PCR assay for simultaneous detection of nine clinically relevant antibiotic resistance genes in Staphylococcus aureus. J Clin Microbiol 2003; 41(9): 4089-4094.
  13. Performance Standards for Antimicrobial Susceptibility Testing. 35th ed. CLSI guideline. Wayne, USA: Clinical and Laboratory Standards Institute; 2025.
  14. Oxoid Manual. The Oxoid manual culture media, ingredients and other laboratory services. Oxoid Limited, Hampshire, UK: 1982.
  15. Graber HU, Casey MG, Naskova J, et al. Development of a highly sensitive and specific assay to detect Staphylococcus aureus in bovine mastitic milk. J Dairy Sci 2007; 90(10): 4661-4669.
  16. Spanu T, Sanguinetti M, D'Inzeo T, et al. Identification of methicillin-resistant isolates of Staphylococcus aureus and coagulase-negative staphylococci responsible for bloodstream infections with the Phoenix system. Diagn Microbiol Infect Dis 2004; 48(4): 221-227.
  17. Lüthje P, Schwarz S. Antimicrobial resistance of coagulase-negative staphylococci from bovine sub-clinical mastitis with particular reference to macrolide-lincosamide resistance phenotypes and genotypes. J Antimicrob Chemother 2006; 57(5): 966-969.
  18. Ng LK, Martin I, Alfa M, et al. Multiplex PCR for the detection of tetracycline resistant genes. Mol Cell Probes 2001; 15(4): 209-215.
  19. Neelam, Jain VK, Singh M, et al. Virulence and anti-microbial resistance gene profiles of Staphylococcus aureus associated with clinical mastitis in cattle. PLoS One 2022; 17(5): e0264762. doi: 10.1371/journal. pone.0264762.
  20. França A, Gaio V, Lopes N, et al. Virulence factors in coagulase-negative staphylococci. Pathogens 2021; 10(2): 170. doi: 10.3390/pathogens10020170.
  21. Authority EFS. The European union summary report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2018/2019. EFSA J 2021; 19(4): 6490. doi: 10.2903/ j.efsa.2021.6490.
  22. El-Razik KAA, Arafa AA, Fouad EA, et al. Phenotypic and genotypic characterization of erythromycin-resistant Staphylococcus aureus isolated from bovine subclinical mastitis in Egypt. Vet World 2023; 16(7): 1562-1571.
  23. Galia L, Ligozzi M, Bertoncelli A, et al. Real-time PCR assay for detection of Staphylococcus aureus, Panton-Valentine leucocidin and methicillin resistance directly from clinical samples. AIMS Microbiol 2019; 5(2): 138-146.
  24. Stefani S, Goglio A. Methicillin-resistant Staphylococcus aureus: related infections and antibiotic resistance. Int J Infect Dis 2010; 14(Suppl 4): S19-S22.
  25. Jamali H, Paydar M, Radmehr B, et al. Prevalence and antimicrobial resistance of Staphylococcus aureus isolated from raw milk and dairy products. Food Control 2015; 54: 383-388.
  26. Gao J, Ferreri M, Yu F, et al. Molecular types and antibiotic resistance of Staphylococcus aureus isolates from bovine mastitis in a single herd in China. Vet J 2012; 192(3): 550-552.
  27. Chambers HF. Methicillin-resistant Staphylococcus aureus. Mechanisms of resistance and implications for treatment. Postgrad Med 2001; 109(2 Suppl): 43-50.
  28. Aarestrup FM, AgersŁ Y, Ahrens P, et al. Antimicrobial susceptibility and presence of resistance genes in staphylococci from poultry. Vet Microbiol 2000; 74(4): 353-364.
  29. Talaat H, El Beskawy M, Atwa S, et al. Prevalence and antibiogram of Staphylococcus aureus in clinical and subclinical mastitis in Holstein dairy cows in Egypt. Zagazig Vet J 2023; 51(1): 59-75.
  30. Hnini R, Silva E, Pinho L, et al. Phenotypic characterization and resistance genes detection of Staphylococcus aureus isolated from bovine mastitis in the northwest of Portugal. Acta Vet Eurasia 2023; 49(3): 127-136.
  31. Aslantaş Ö, Öztürk F, Ceylan A. Prevalence and molecular mechanism of macrolide and lincosamide resistance in staphylococci isolated from subclinical bovine mastitis in Turkey. J Vet Med Sci 2011; 73(12): 1645-1648.
  32. Gad WA, Osman SA, Abd El-Razik KA, et al. A novel diagnostic technique for diagnosis of Staphylococcus aureus subclinical mastitis using gold nanoparticle-based ELISA. Open Vet J 2024; 14(12): 3388-3396.‏
Veterinary Research Forum
Volume 16, Issue 6
June 2025
Pages 317-323

  • Receive Date 11 August 2024
  • Revise Date 16 November 2024
  • Accept Date 25 December 2024

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