Molecular Typing and Antimicrobial Susceptibility Profile of Staphylococcus aureus Isolates Recovered from Bovine Mastitis and Nasal Samples

Abstract

In the present study, we aimed to determine the antimicrobial resistance and molecular typing of Staphylococcus aureus recovered from transient and persistent intramammary infections and nares/muzzles in dairy cows. We investigated the antimicrobial resistance of 189 S. aureus strains using a broad antimicrobial susceptibility profile. Furthermore, 107 S. aureus isolates were strain-typed using staphylococcal protein-A (spa) typing. A large proportion of strains exhibited multidrug resistance to antimicrobials, including resistance to critically important antimicrobials, although no methicillin-resistant S. aureus strains were found. Our study did not strengthen the idea that extramammary niches (i.e., nares/muzzles) are an important source of S. aureus for bovine mastitis. A discrepancy in the antimicrobial resistance between S. aureus strains isolated from nares/muzzles and milk samples was observed. Furthermore, S. aureus isolates from transient and persistent intramammary infections (IMIs) did not differ by spa typing, suggesting that the persistence of bovine IMIs was determined by cow factors. Thus, the high level of multidrug-resistant S. aureus found in the two herds, considered together with the predominance of a well udder-adapted S. aureus strain, may contribute to our knowledge of the history of the high prevalence of mastitis caused by S. aureus, which is of great concern for animal and public health.

Distinct behavior of bovine-associated staphylococci species in their ability to resist phagocytosis and trigger respiratory burst activity by blood and milk polymorphonuclear leukocytes in dairy cows

“…Twelve Staphylococcus aureus isolates originating from aseptically collected milk samples (n = 6) and noses (n = 6) obtained from 2 Brazilian dairy herds (Souza et al, 2016a;Cunha et al, 2020;Santos et al, 2020) were available. These isolates were previously identified phenotypically by biochemical tests (Souza et al, 2016a), confirmed by MALDI-TOF MS and molecular identification targeting a portion of the conserved S. aureus thermonuclease gene (Santos et al, 2020).…”

“…Twelve Staphylococcus aureus isolates originating from aseptically collected milk samples (n = 6) and noses (n = 6) obtained from 2 Brazilian dairy herds (Souza et al, 2016a;Cunha et al, 2020;Santos et al, 2020) were available. These isolates were previously identified phenotypically by biochemical tests (Souza et al, 2016a), confirmed by MALDI-TOF MS and molecular identification targeting a portion of the conserved S. aureus thermonuclease gene (Santos et al, 2020). Additionally, a collection of 38 different NAS isolates obtained from 13 Flemish dairy herds during previous studies (Piessens et al, 2011;Supré et al, 2011;De Visscher et al, 2016) was available as well: 5 S. chromogenes isolates originating from teat apices (TA; De , 10 S. chromogenes isolates originating from aseptically collected milk samples (Supré et al, 2011), 5 Staphylococcus haemolyticus isolates originating from TA (De Visscher et al, 2016), 5 S. haemolyticus isolates from aseptically collected milk samples (Supré et al, 2011), 5 S. fleurettii isolates originating from aseptically collected milk samples (Supré et al, 2011), and 8 S. fleurettii isolates originating from cows' environment (Piessens et al, 2011).…”

Staphylococcus aureus Protection-Related Type 3 Cell-Mediated Immune Response Elicited by Recombinant Proteins and GM-CSF DNA Vaccine

“…The produced synthetic genes were cloned into the pUC57 vector and then sub-cloned into the pET28a expression vector [ 16 ]. Recombinant plasmids were used to transform the expression strain E. coli BL21-Star™(DE3) as previously described [ 17 ] with modifications. Briefly, transformed E. coli BL21-Star™(DE3) were selected on kanamycin plates.…”

“…An udder adapted S. aureus isolate originated from a case of chronic subclinical IMI was used [ 17 ]. Staphylococcus aureus (spa typing t605) inoculum was prepared as previously described [ 20 ] with minor modifications.…”

Expression of L-selectin (CD62L) and CD44 on Bovine Lymphocytes and WC1.1+ γδ T Cells under Stimulation with Staphylococcus aureus

“…One of the most common bovine mastitis pathogens is Staphylococcus aureus, which is a notable issue for dairy farming due to its pathogenicity, contagiousness, the likelihood of persistence in the form of intramammary infections, and poor cure rates associated with current antimicrobial therapies; this pathogen has unquestionable importance in veterinary and human medicine [1][2][3]. This bacterium is also known to be part of the skin microbiota [4,5].…”