Investigation of biofilm production and icaA and icaD genes in Staphylococcus aureus isolated from heifers and cows with mastitis

Abstract

Biofilm formation and antimicrobial resistance of Staphylococcus aureus are important virulence factors in cases of mastitis in dairy cows. However, few studies have investigated mastitis strains isolated from heifers. Within this context, the objective of the present study was to investigate biofilm formation on Congo red agar, the presence of the icaA and icaD genes by polymerase chain reaction (PCR), and the percentage of in vitro antimicrobial resistance of 110 S. aureus isolates from mammary gland secretions of heifers and cows with mastitis. PCR detected the icaA and icaD genes in 98% and 100% of isolates, respectively. However, only 55.5% of all isolates produced a biofilm on Congo red agar. Antimicrobial susceptibility testing revealed that 47.0% of isolates from heifers and 70.4% of isolates from cows were resistant to at least one of the antimicrobial agents tested. Resistance to penicillin and/or ampicillin was the most frequent (44.5%). These results indicate the need to implement prophylactic and control measures of mastitis for heifers. Heifers and cows can carry resistant strains with the capacity of biofilm production, a fact representing a threat to public health and animal well-being and generating losses to dairy farmers.

Therapeutic effects of a combined antibiotic-enzyme treatment on subclinical mastitis in lactating dairy cows

“…The results of this study contradict those of previous studies showing that formation of biofilm has an impact on the efficacy of antimicrobial therapy and the subsequent outcome of infection (Gotz 2002;Parsek and Fuqua 2004;Castelani et al 2015; Krewer et al 2015). This may be due to the fact that biofilm production in the mammary tissue is different from the in vitro situation.…”

“…Biofilms are complex communities of microorganisms attached to surfaces and surrounded by a matrix of extracellular polymer (Davey and O'Toole 2000). Biofilm formation is an important element determining the pathogenicity and antimicrobial resistance of bacteria (Snel et al 2014;Castelani et al 2015;Krewer et al 2015). Biofilms can decrease or block the penetration of antibiotics by formation of a physical barrier or can bind to antibiotics with their negatively charged exopolysaccharides.…”

Genotypic and phenotypic detection of capsular polysaccharide and biofilm formation in Staphylococcus aureus isolated from bovine milk collected from Brazilian dairy farms

“…Studies conducted with S. aureus isolated from bovine mastitis in different countries reported the concomitant presence of both genes in most of the S. aureus isolates analysed (Vasudevan et al 2003;Cucarella et al 2004;Szweda et al 2012;Melo et al 2013;Prenafeta et al 2014;Bar-Gal et al 2015;Castelani et al 2015;Fabres-Klein et al 2015). Moreover, other studies (Ciftci et al 2009;Dhanawade et al 2010;Coelho et al 2011;Darwish and Asfour 2013;Marques et al 2013) reported that lower percentages of S. aureus of bovine origin harboured these genes.…”

Antimicrobial Resistance in Farm Animals in Brazil: An Update Overview

“…Among heifer isolates, 39.6% and 14.5% were resistant to penicillin G and ampicillin, respectively. In the case of cow isolates, 62.9% and 40.7% were resistant to penicillin G and ampicillin, respectively [111].…”

“…Penicillin G resistance frequencies have ranged from 30.4% to 100% in the studies published in the last ten years [100,101,109,110]. Some studies have also tested other PSLPs, sometimes with slightly higher resistance frequencies than penicillin G [106,[111][112][113].…”