Antimicrobial Resistance ofStaphylococcus aureusIsolates from Dairy Cows and Genetic Diversity of Resistant Isolates

Abstract

Staphylococcus aureus is a frequent and major contagious mastitis bacterial pathogen. The antibiotic treatment cure rates vary considerably from 4% to 92%. Staphylococcus aureus readily becomes resistant to antibiotics, resulting in persistent noncurable intramammary infection that usually results in culling of infected animals. Because of its notorious ability to acquire resistance to the commonly used as well as last resort antimicrobials such as methicillin and vancomycin and the development of multidrug-resistant strains, antimicrobial resistance (AMR) in S. aureus is of paramount importance in human medicine. The objective of this study was to evaluate the prevalence of AMR and genetic diversity of S. aureus isolates from milk of dairy cattle. Staphylococcus aureus isolates (n = 239) from 33 dairy farms in Tennessee were tested against 10 antimicrobials by broth microdilution method using the Sensititer system. Genetic diversity of resistant isolates was evaluated by pulsed-field gel electrophoresis (PFGE). Overall, AMR of the S. aureus isolates varied from as low as 1.3% for ceftiofur to as high as 25% for sulfadimethoxine. Out of 239 S. aureus isolates, 82 (34.3%) of them were resistant to at least 1 of the 10 antimicrobials. The AMR isolates belonged to two major PFGE types, indicating the presence of dominant clonal patterns among the resistant isolates. In general, there was a variation of prevalence of AMR within and among farms over time, with an increasing trend in tetracycline resistance. Judicious use of antimicrobials in dairy cattle farms can reduce the development of antimicrobial-resistant S. aureus.

Surveillance of Antibiotic Resistance of Maltose-Negative Staphylococcus aureus in South African Dairy Herds

“…A similar study in dairy cattle in Tennessee also established a variation of prevalence of antibiotic resistance of S. aureus, with an increasing trend in tetracycline resistance [ 40 ]. These conclusions followed the report identifying the predominant antibiotic groups used in animal health in South Africa from 2014 to 2015, as the growth promoters (animal use only antibiotics) (62%) followed by tetracyclines (17%) and macrolides (11%) [ 41 ].…”

“…As generalised models, they allow a nonlinear relationship between the dependent variable (variable to be explained) and the model parameters [ 50 ]. In the univariate multivariable GLMM [ 40 ], the drug-specific antibiotic resistance of all S. aureus isolates was used as the dependent variable. As it is a binomial variable a logit link function was used.…”

Microbiological Safety and Antibiogram Analysis of Selected Food Products Obtained in the Marketplace of Peshawar and Mardan, KPK, Pakistan

“…The resistance of microbial isolates to a drug was also determined in terms of percent isolates showing resistance to a specific drug. Relatively the highest resistance frequency was observed towards Methicillin as compared to other antibiotics used against Gram-positive isolates [5,15]. A similar level of resistance was observed in Gram-negative bacterial isolates towards Cefixime, Cefuroxime, and Linezolid.…”

“…Different sets of rice were mixed; if these vanished then detection of B. cereus would be difficult in fried rice. The methicillin-resistant Staphylococcus aureus infections have been reported in the USA for up to 30 years [5,15]. Clostridium perfringens is usually found in raw meat, soil and the intestinal tract of humans [16,17].…”

Surveillance of antimicrobial resistance of maltose negative Staphylococcus aureus in South African dairy herds

“…A similar study in dairy cattle in Tennessee also found that there was a variation of prevalence of antimicrobial resistance of S. aureus, with an increasing trend in tetracycline resistance [1]. This was also in accordance with the report which showed that the predominant antimicrobial groups used in animal health in South Africa from 2014 to 2015, were the growth promoters (animal-use-only antimicrobials) (62%) followed by tetracyclines (17%) and macrolides (11%) [23].…”