Insight into the Biology of Antiseptic Resistance in Staphylococcus Aureus
Abstract
Staphylococcus aureus has coevolved with humans for thousands of years. The ubiquitous presence of S. aureus on the skin and in the environment results in high rates of human exposure to this formidable pathogen. To limit infections caused by S. aureus, humans have enlisted antiseptics for over 100 years. Two antiseptics that are used universally in healthcare facilities are chlorhexidine and quaternary ammonium compounds. Given their high rates of usage, decreased S. aureus susceptibility to these compounds has been identified and is associated with the presence of specific multidrug efflux pumps, such as QacA, QacC, and NorA. Although these pumps have been studied individually in different S. aureus backgrounds, little is known about the phenotype of strains that possess all three efflux pumps, or the expression of these genes after exposure to subinhibitory antiseptic compounds. Given the presence of all three pumps in clinical isolates, we hypothesized that such a strain would have increased resistance to certain antiseptics. To address this hypothesis, we engineered isogenic strains of S. aureus that harbored the aforementioned efflux pumps individually or in different combinations and viithen tested their resistance to a panel of antiseptic compounds. Indeed, we demonstrated that carrying all three efflux pumps increased protection to a commonly used antiseptic. Furthermore, we showed preexposure to one antiseptic can subsequently increase tolerance to a different antiseptic. In S. aureus, QacA is the prototypical antiseptic resistance-mediating efflux pump. Although epidemiological studies have identified the prevalence of qacA-positive S. aureus strains within defined populations, little is known about the genetic background of these strains. We hypothesized that S. aureus isolates that harbored qacA would carry qacA on different plasmid backbones.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 28, 2019
- Accession Number
- AD1181531
Entities
People
- Patrick T. Labreck
Organizations
- Uniformed Services University of the Health Sciences