Staphylococci isolated from animals and food with phenotypically reduced susceptibility to β-lactamase-resistant β-lactam antibiotics

Abstract

The antibiotic resistance pattern of 1921 Staphylococcus strains isolated from animals and food within the last two years were examined using diffusion tests. Among them there were only 35 strains of S. aureus having an inhibition zone diameter of 15 mm or less, and 4 strains of coagulase-negative staphylococci (CNS) having a zone diameter of 18 mm or less to 1-µg oxacillin disk. These 39 strains were examined also by E-test to oxacillin and for the detection of the mecA gene by PCR in order to determine whether they might be real methicillinresistant staphylococci. Among the 39 strains there were only two that were susceptible to penicillin by disk diffusion method; however, further examination by the penicillinase test showed that they produced β-lactamase. While 19 (15 S. aureus, 4 CNS) strains were resistant and 7 strains were intermediate to oxacillin in disk diffusion test, the E-test gave 8 resistant and 5 intermediate results. Six out of the 8 oxacillin-resistant strains examined by disk diffusion and E-test harboured the mecA gene. Thus only 6 out of the examined 1921 strains proved to be mecA positive. These methicillin-resistant, mecA-positive strains (5 of the S. aureus strains and 1 of the S. epidermidis) originated from two dairy herds. The results prove that methicillin-resistant S. aureus (MRSA) strains in animals are really rare in Hungary. Eighteen strains were chosen and screened for minimal inhibitory concentration (MIC) of oxacillin with or without clavulanic acid or sulbactam, and three of them produced methicillinase enzyme.

Isolation and characterization of methicillin-resistantStaphylococcus aureus from livestock and poultry meat

“…There were no significant phenotypic differences observed between isolates from different sources, which mean probably the same potential of pathogenicity. Several reports suggest that the transfer of S. aureus between human and cattle is possible and that the infection of humans by transmission through food products contaminated with animal MRSA is very plausible (Roberson et al, 1994;Zadoks et al, 2000;Lee, 2003;Kaszanyitzky et al, 2004).…”

“…In a study by Kaszanyitzky et al (2004), a total of 1005 staphylococcal strains were isolated from carcasses or samples of different animal species and analysis indicated that only 21 were confirmed as methicillin resistant S. aureus (19 originated from cows, 1 poultry and one from horse), six of these harboured the mecA gene. In Hungary, 806 staphylococci from different sources were isolated and only 2% of S. aureus from cattles were resistant to methicillin and were mecA-negative, none of the isolates from pigs and poultry were MRSA (Kaszanyitzky et al, 2004).…”

“…In Hungary, 806 staphylococci from different sources were isolated and only 2% of S. aureus from cattles were resistant to methicillin and were mecA-negative, none of the isolates from pigs and poultry were MRSA (Kaszanyitzky et al, 2004). Lee (2003) indicated that among 1,913 specimens collected from animals in southern Korea, 421 contained S. aureus, of these, 28 specimens (6.7 %) were MRSA (resistant to concentrations of oxacillin higher than 2 µg/ml) and among them 15 (3.6%) were mecA gene positive.…”

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

“…The most effective antibiotics were enrofloxacin, streptomycin and gentamicin. This high sensitivity was also demonstrated in other studies (Kaszanyitzky et al, 2004;Byarugaba, 2004). Despite these data, Freitas et al (2005) reported high resistance level to gentamicin in CoNS isolated in regions where this antibiotic was used.…”

Resistência bacteriana e ação das bacteriocinas de Lactobacillus spp em Staphylococcus aureus isolados de mastite bovina

“…Kaszanyitzky et al, 2004). A transmissão desses genes pode envolver tanto espécies patogênicas como membros da microbiota indígena dos hospedeiros.…”