Genotypic evaluation of antimicrobial resistance in Staphylococcus spp. isolated from bovine clinical mastitis

Abstract

Bovine clinical mastitis caused by Staphylococcus spp. is a serious and widespread disease in the world of dairy farming. Antimicrobial therapy is of fundamental importance in the prevention and treatment of infectious mastitis, but the indiscriminate use of antimicrobials acts as a determining factor for the spread of the disease. The present study evaluated the resistance profiles of 57 Staphylococcus spp. isolated from bovine clinical mastitis to beta-lactams and gentamicin, relating characteristics of phenotype (in vitro susceptibility tests) and genotype (detection and expression of genes encoding resistance - mecA, mecALGA251, blaZ, femA, femB, and aacA-aphD - using PCR and RT-PCR, respectively). One or more genes coding for resistance to different antimicrobials were detected in 50 Staphylococcus spp. isolates. The femA and femB genes were the most frequent (75.4% for both). The observed expression of the genes was as follows: blaZ (60%), femA (39.5%), aacA-aphD (50%), femB (32.6%), mecA (8.3%), and mecALGA251 (0%). Considering the relevance of the genus Staphylococcus to bovine mastitis, this study aimed to elucidate aspects regarding the genotypic and phenotypic profiles of these microorganisms so as to contribute to the development of effective strategies for mastitis control.

Research Article Pulsed-field gel electrophoresis genotyping and antimicrobial resistance profiles of <i>Staphylococcus</i> <i>aureus</i> isolated from subclinical mastitis in dairy cattle in Brazil

“…The high percentage of strains resistant to β-lactams in the present study was similar to that observed in other previous studies (Daka et al, 2012;Xavier et al, 2017;Benites et al, 2021). In Brazil, resistance to β-lactams has also been observed from 18 to 95% in S. aureus isolated from bovine milk (Medeiros et al, 2009;Silva et al, 2012;Ferreira et al, 2016;Girardini et al, 2016;Carvalho et al, 2018).…”

“…There is a major public and animal health concern about infections caused by antimicrobial resistant S. aureus. Recent studies evaluating S. aureus isolated from bovine mastitis reported resistance of this pathogen to antimicrobials widely used in veterinary and human medicine, especially to β-lactam antibiotics (Oliveira et al, 2012;Xavier et al, 2017;Benites et al, 2021;Freu et al, 2022). Understanding the epidemiology of antimicrobial resistance of S. aureus causing mastitis may allow the development of preventive strategies to decrease existing resistance and prevent the emergence of new strains of resistant S. aureus.…”

Molecular epidemiology and characterization of antimicrobial-resistant Staphylococcus haemolyticus strains isolated from dairy cattle milk in Northwest, China

“…Because of the ubiquitous nature and acquisition of ARGs by these microbial agents, it is important to understand their epidemiology through the molecular approaches mentioned above ( Srednik et al., 2017 ; Benites et al., 2021 ). The Northwest region of China is an important agricultural and pastoral region with much potential for the dairy industry in Gansu, Ningxia, Qinghai, and Xinjiang provinces, and the status of AMR among NAS, particularly S. haemolyticus isolated from the dairy herd is still unknown in the northwest region of China.…”