Decreased susceptibility to chlorhexidine and prevalence of disinfectant resistance genes among clinical isolates of Staphylococcus epidermidis

Abstract

Staphylococcus epidermidis is a versatile agent, being both a commensal and a nosocomial pathogen usually with an opportunistic role in association with implanted foreign body materials. Pre-operative antiseptic preparation is an important strategy for reducing the risk of complications such as surgical site infection (SSI). Currently, the most widely used antiseptics are alcohols, quaternary ammonium compounds (QACs), and the bisbiguanide chlorhexidine. Occurrence of resistance to the latter agent has drawn increasing attention. The aim of this study was to investigate if decreased susceptibility to chlorhexidine among S. epidermidis was present in our setting, a Swedish university hospital. Staphylococcus epidermidis (n = 143), retrospectively collected, were obtained from prosthetic joint infections (PJI) (n = 61), post-operative infections after cardiac surgery (n = 31), and the skin of the chest after routine disinfection prior to cardiac surgery (n = 27). In addition, 24 commensal isolates were included. Minimum inhibitory concentration (MIC) of chlorhexidine was determined on Mueller Hinton agar plates supplemented with serial dilutions of chlorhexidine. Five QAC resistance genes, qacA/B, smr, qacH, qacJ, and qacG, were detected using PCR. Decreased susceptibility to chlorhexidine was found in 54% of PJI isolates, 68% of cardiac isolates, 21% of commensal isolates, and 7% of skin isolates from cardiac patients, respectively. The qacA/B gene was present in 62/143 isolates (43%), smr in 8/143 (6%), and qacH in one isolate (0.7%). The qacA/B gene was found in 52% of PJI isolates, 61% of cardiac isolates, 25% of commensal isolates, and 19% of the skin isolates. In conclusion, decreased susceptibility to chlorhexidine, as well as QAC resistance genes, were prevalent among S. epidermidis isolates associated with deep SSIs.

Diversity of antimicrobial resistance and virulence genes in methicillin-resistant non-Staphylococcus aureus staphylococci from veal calves

“…Regarding to S. epidermidis, some isolates had incomplete forms of the combination aphA3-aadE-sat, as has been described for S. epidermidis isolates from pets (Kern and Perreten, 2013). Some S. epidermidis isolates carried the spc, qac, fosB, merA and/or merB genes, which have previously been described in S. epidermidis related to the nosocomial setting (Gill et al, 2005;Prag et al, 2014) and the food industry (Heir et al, 1999;Zhang et al, 2003). In our study, some S. epidermidis isolates carried the genes cat(pC194/pMC524) or dfrD, that have been reported rarely in animal staphylococci (Wendlandt et al, 2013).…”

Methicillin-Resistant Staphylococcus aureus in Commercial Swine Herds Is Associated with Disinfectant and Zinc Usage

“…A selection of genes responsible for tolerance to quaternary ammonium compounds (QACs) (qacAB, qacG, qacH, qacJ, and smr) was evaluated using a real-time PCR protocol (22). The amplification and melting curves were assessed for agreement with controls, and the products were confirmed by sequencing.…”

Antiseptic solutions modulate the paracrine‐like activity of bone chips: differential impact of chlorhexidine and sodium hypochlorite

“…, Prag et al. ). This research is a logical extension of previous studies describing the paracrine‐like function of bone chips in vitro – bone chips that were freshly prepared (Caballe‐Serrano et al.…”

“…Antiseptic solutions are widely used in preventive and regenerative dentistry for procedures such as mouth rinsing prior and after surgical interventions (Prag et al. ), irrigation of pockets around implants (Pedrazzi et al. ), and decontamination of extraction cavities (Haraji & Rakhshan ).…”