Antimicrobial Drug Susceptibility of Staphylococcus aureus Strains Isolated from Bovine and Ovine Mammary Glands

Abstract

The activity of selected antimicrobial agents against Staphylococcus aureus was determined with the agar disk diffusion test to determine the diameter of the zone of inhibition and the E-test for determination of the minimal inhibitory concentration (MIC). The 92 S. aureus strains used in this study were isolated from bovine (n = 76) and ovine (n = 16) intramammary infections. Four antibiotics, which are frequently used in mastitis therapy were chosen: penicillin-G, ampicillin, kanamycin, and cephalexine. The fifth compound (oxacillin) was used to detect methicillin-resistant S. aureus, but no such strains could be found. According to the evaluation criteria, 65.2 (penicillin) to 93.5% (kanamycin, cephalexine) S. aureus strains were susceptible to the antibiotics tested. Ovine S. aureus strains reveal a lower resistance rate than bovine isolates. Comparison of the results of the two methods of susceptibility testing shows, with exception of penicillin and ampicillin, satisfactory agreement. Analyzing the results of the MIC endpoints and the zone diameter values, very major errors, according to the error rate bounded method of Metzler and DeHaan, occurred at an error rate of 3.3% for penicillin and 3.8% for ampicillin.

Development of multiplex polymerase chain reaction assay for rapid detection of Staphylococcus aureus and selected antibiotic resistance genes in bovine mastitic milk samples

“…In a previous study that compared the resistant results between 2 methods of susceptibility testing, some error was detected for intermediate, susceptible, and resistant results. 16 Though some discordance may exist, the developed multiplex PCR method could be chosen as a fast, practical, and economical technique for the detection of S. aureus and related antibiotic resistance. In practice, antibiotic resistance of mastitis pathogens is only one of the key factors to influence therapy.…”

Antibiotic Resistance in the Environment, with Particular Reference to MRSA

“…Penicillin and ampicillin resistance are more widespread (Gentilini et al, 2000;Guler et al, 2005) due to the frequent use of these antibiotics in treating intramammary infections (Pengov and Ceru, 2003). Antibacterial treatment for mastitis has been implicated as a major cause of resistance in bacterial isolates from treated animals, other animals within the herd, and in meat products intended for human consumption (Berghash et al, 1983;Chen et al, 2004;Griggs et al, 1994;Piddock, 1996).…”

Effect of Combination Therapy with Lactoferrin and Antibiotics against Staphylococcal Mastitis on Drying Cows

“…On the other hand, Lf has low anti-bacterial activity against the some strains of S.aureus that were isolated from bovine mastitic MGSs [29]. Therefore, these reports indicated that Lf acted with penicillin G to enhance the phagocytes of S.aureus by bovine polymorphonuclear neutrophils and to decrease the invasion of mammary epithelial cells [7].…”

“…Therefore, the many therapeutic methods have been reported, such as antibiotics [8,28,29], cytokines [30,35], immunoglobulin [1], vaccines [27,34], disinfectants [10,11,38] and biologically active substrates [16,19].…”