Antibiotic Resistance in <i>Staphylococcus aureus</i> Strains Isolated from Cows with Mastitis in Eastern Poland and Analysis of Susceptibility of Resistant Strains to Alternative Nonantibiotic Agents: Lysostaphin, Nisin and Polymyxin B

Abstract

The aim of this study was to analyze the resistance of Staphylococcus aureus isolates from bovine mastitis in the eastern part of Poland to a set of 20 antibiotics and three alternative agents: lysostaphin, nisin and polymyxin B. Eighty-six out of 123 examined isolates were susceptible to all 20 tested antibiotics (70%). The highest percentage of resistance was observed in the case of β-lactam antibiotics: amoxicillin (n=22, 17.9%), ampicillin (n=28, 22.8%), penicillin (n=29, 23.6%) and streptomycin (n=13; 10.6%). Twenty-five of the penicillin-resistant strains were found to carry the blaZ gene coding for β-lactamases. Two strains were found to be mecA positive and a few strains were classified as multidrug resistant (MDR), one of them was simultaneously resistant to six antibiotics. All strains, resistant to at least one antibiotic (n=37) and two control strains, were susceptible to lysostaphin with MIC values of 0.008–0.5 µg/ml (susceptibility breakpoint 32 µg/ml). Twenty-one (54%) isolates were susceptible to nisin. The MIC value of this agent for 17 (44%) strains was 51.2 µg/ml and was not much higher than the susceptibility breakpoint value (32 µg/ml). Polymyxin B was able to inhibit the growth of the strains only at a high concentration (32–128 µg/ml). The presented results confirmed the observed worldwide problem of spreading antibiotic resistance among staphylococci isolated from bovine mastitis; on the other hand, we have indicated a high level of bactericidal activity of nisin and especially lysostaphin.

Antimicrobial profile of multidrug-resistant Staphylococcus spp. isolated from bovine mastitis cases in the northwest region of Paran State, Brazil

“…isolated from bovine mastitis. Similar results were also found in different regions of the world (Szweda et al, 2014;Güller et al, 2005, Sawant et al, 2009.…”

Nanoparticles for treatment of bovine Staphylococcus aureus mastitis

“…Treatment of mastitis by antibiotics is still under debate to develop a standard treatment regime to obtain satisfactory effects (du Preez, 2000) due to persistent intracellular existence with different forms protected it from antibiotics and host defense mechanism after that; they can relapse to more infectious wild-type phenotype, probably causing recurrent infection. Besides, large usage of antibiotics for the long-term increasingly leads to the resistance of S. aureus to antibiotics (Szweda et al, 2014).…”

Additive antibacterial activity of naringenin and antibiotic combinations against multidrug resistant Staphylococcus aureus

“…Staphylococcus aureus (S. aureus) is the leading cause of both nosocomial and community acquired infections (Lowy, 1998) and is often isolated from the bloodstream, skin and soft tissue infections (Bernards et al, 1998;Pfaller et al, 1999;Deresinski, 2005). Disconcertingly, because methicillin-resistant S. aureus (MRSA) strains carry multiple genes of antibiotic resistance, many have developed resistance to a variety of commonly used antimicrobials and may, in future, become resistant to newly developed antimicrobial agents as well (Vijaya et al, 2013;Xia et al, 2013;Medeiros et al, 2014;Szweda et al, 2014). Hence, alternative methods, such as natural plant products, are being studied for their potential to alleviate the burden created by the multidrug resistant bacteria such as MRSA.…”