Journal Article

Vancomycin-resistant Staphylococcus aureus endangers Egyptian dairy herds

Tartor, Yasmine H., Algendy, Reem M., Mahmmod, Yasser, Elsohaby, Ibrahim, Enany, Mohamed E., Ismail, Noreen I., Eidaroos, Nada H., El-Demerdash, Azza S.

2024

Overview

The emergence of pandrug-resistant (PDR) and extensive drug-resistant (XDR) methicillin-resistant and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) isolates from bovine milk samples along with biofilm formation ability and harboring various virulence genes complicates the treatment of bovine mastitis and highlights the serious threat to public health. This study investigated for the first time the frequency, antimicrobial resistance profiles, biofilm-forming ability, virulence factors, spa and staphylococcal cassette chromosome mec (SCC mec ) types of MRSA and VRSA isolated from clinical and subclinical bovine mastitis in Egypt. A total of 808 milk samples were collected from each quarter of 202 dairy animals, including 31 buffaloes and 171 cattle. The frequency of mastitis in the collected milk samples was 48.4% (60/124) in buffaloes and 29.2% (200/684) in cattle. A total of 65 Staphylococcus species isolates were recovered, including 27 coagulase-positive S. aureus (CoPS) isolates and 38 coagulase-negative staphylococci (CoNS). The CoNS included 27 mammaliicocci (20 Mammaliicoccus lentus and 7 M. sciuri ) and 11 Non-aureus staphylococci ( S. lugdunensis ) isolates. All the CoPS isolates were mec A positive and resistant to 20–33 tested antimicrobials with multiple antibiotic resistance index ranging from 0.61 to 1. Three isolates were PDR, four were XDR, and 20 were multidrug resistant isolates. VRSA was detected in 85.2% of CoPS isolates with minimal inhibitory concentration (MIC) ranging from 64 to 1024 µg/mL. The van A gene was found in 60.8%, van B in 73.9%, and both genes in 43.5% of VRSA isolates. All the CoPS isolates exhibited biofilm formation ability, with 55.6% being strong, and 44.4% moderate biofilm producers, and harbored ica A (74.1%) and ica D (74.1%) biofilm-forming genes. All S. aureus isolates harbored both beta-haemolysin ( hlb ) and leucotoxin ( luk MF) genes, while 44.4% were positive for toxic shock syndrome toxin ( tsst ) gene. Enterotoxin genes sea , seb , sec , sed , and see were found in 59.3%, 40.7%, 18.5%, 33.3%, and 14.8% of isolates, respectively. Additionally, 70.4% of the isolates had  spa X-region gene, and exhibited eight different MRSA spa types (t127, t267, t037, t011, t843, t1081, t2663, and t1575), with spa t127 being the most common. Three SCC mec types (I, II and III) were identified, with SCC mec I being predominant, and were further classified into subtypes 1.1.1, 1.1.2, 1.n.1, and 4.1.1. The ability of MRSA and VRSA isolates to produce biofilms and resist antimicrobials highlights the serious threat these pathogens pose to bovine milk safety, animal welfare, and public health. Therefore, strict hygiene practices and antimicrobial surveillance are crucial to reduce the risk of MRSA and VRSA colonization and dissemination.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 631/326 / 692/699 / Animal welfare / Animals / Anti-Bacterial Agents - pharmacology / Antibiotic resistance / Antimicrobial agents / Antimicrobial resistance / Biofilm / Biofilms / Biofilms - drug effects / Buffaloes / Cattle / Coagulase / Cow's milk / Dairying / Drug resistance / Egypt / Female / Gene frequency / Genes / Genotyping / Humanities and Social Sciences / Hygiene / Mastitis / Mastitis, Bovine - microbiology / Methicillin / Methicillin-Resistant Staphylococcus aureus - drug effects / Methicillin-Resistant Staphylococcus aureus - genetics / Methicillin-Resistant Staphylococcus aureus - isolation & purification / Microbial Sensitivity Tests / Milk / Milk - microbiology / MRSA / multidisciplinary / Multidrug resistance / Pandrug-resistant / Public health / Risk reduction / S. aureus / Science / Science (multidisciplinary) / Septic shock / Staphylococcal enterotoxin F / Staphylococcal Infections - drug therapy / Staphylococcal Infections - microbiology / Staphylococcal Infections - veterinary / Staphylococcus aureus / Staphylococcus infections / Toxic shock syndrome / Toxins / VanA gene / Vancomycin / Vancomycin - pharmacology / Vancomycin-Resistant Staphylococcus aureus - drug effects / Vancomycin-Resistant Staphylococcus aureus - genetics / Virulence / Virulence factors / Virulence Factors - genetics / VRSA