Phenotypic Resistance to Disinfectants and Antibiotics in Methicillin‐Resistant Staphylococcus aureus Strains Isolated from Pigs

Abstract

The aim of this research was to study the phenotypic resistances to disinfectants and antibiotics in strains of methicillin-resistant Staphylococcus aureus (MRSA) obtained from Canary black pigs. Analyses were performed on 54 strains of MRSA, isolated in Canary black pigs from the province of Tenerife (Spain); all of them carried the mecA gene. The strains were isolated by means of nasal swab samples of healthy pigs, collected under veterinarian supervision. Bactericidal activity of antiseptics and disinfectants was tested by means of the dilution-neutralization method. Susceptibility to the disinfectants glutaraldehyde, peracetic acid and silver nitrate was assessed, as well as to the antiseptics chlorhexidine, benzalkonium chloride and povidone iodine. Susceptibility to a wide array of antibiotics representing the main groups was determined by means of the disc diffusion method. All the strains demonstrated susceptibility to the disinfectants tested at the recommended concentration, and even to dilutions equal to or lesser than 1/16. The most effective antiseptic and disinfectant were, respectively, chlorhexidine and silver nitrate. With regard to the antibiotics, the strains proved to be multiresistant. All presented phenotypic resistance to the β-lactam antibiotics ampicillin, penicillin and cefoxitin, as well as to numerous aminoglycosides, tetracycline and trimethoprim-sulfamethoxazole. It was also observed that 61.1% of the strains were carriers of plasmids. Our results underline that in the strains such as MRSA, which show multiple resistances to antibiotics, the antiseptics and disinfectants show great efficacy. Moreover, as other authors also suggest, for the treatment and prevention of infections caused by MRSA, the use of β-lactam and aminoglycoside antibiotics may be less effective.

Prevalence of methicillin resistant Staphylococcus aureus (MRSA) in pigs and workers at abattoirs in Trinidad and Tobago

“…All MRSA strains isolated were resistant to cefoxitin, penicillin and ampicillin, a finding in agreement with the report that MRSA isolates are usually resistant to βlactams [4,37]. Similarly, a high frequency of resistance (88.9%) was detected to tetracycline amongst MRSA strains in our study, a finding in agreement with published reports [37,38].…”

“…All MRSA strains isolated were resistant to cefoxitin, penicillin and ampicillin, a finding in agreement with the report that MRSA isolates are usually resistant to βlactams [4,37]. Similarly, a high frequency of resistance (88.9%) was detected to tetracycline amongst MRSA strains in our study, a finding in agreement with published reports [37,38]. The high frequency of resistance exhibited to by MRSA strains to penicillin, ampicillin, streptomycin and tetracycline in our study may be attributed to their frequent use in veterinary practice in the country [16].…”

Genomic Sequencing Reveals the Diversity of Seminal Bacteria and Relationships to Reproductive Potential in Boar Sperm

“…With respect to the pig raising environment, the stringency of the ultraviolet radiation that has a certain bactericidal effect and results in the decrease of bacteria in the pigpen in summer ( Baubinas et al, 1983 ; Kraemer et al, 2018 ). On the other hand, the high temperature in summer strengthens disease prevention and control, especially using much more antibiotics to reduce the production of bacteria to some extent ( Espigares et al, 2017 ; Johnson et al, 2017 ). Although there is no direct evidence linking microbial diversity in summer boar semen to antibiotic use, the high dosage utilization of antibiotics can alter the composition of gut microbes in pigs ( Zhang et al, 2018 ).…”

Limited association between disinfectant use and either antibiotic or disinfectant susceptibility of Escherichia coli in both poultry and pig husbandry

“…Laboratory-based adaptation experiments have shown that step-wise exposure of initially susceptible bacteria to subinhibitory concentrations of benzalkoniumchloride, chlorhexidine, triclosan and some commercial disinfectants may lead to decreased susceptibility to either antibiotics or disinfectants [6–9]. Recent studies investigated the disinfectant susceptibility of bacteria isolated from live-stock and its environment [10–14] or evaluated the correlation [2, 15] or association [16] between antibiotic resistance and a decreased susceptibility to disinfectants. However, in marked contrast to the in vitro reports, no evidence that the use of disinfectants selects for antimicrobial resistance under practical conditions was found.…”