The prevalence of antiseptic tolerance genes among staphylococci and enterococci in a pediatric population
Lauren M Sommer1, Jennifer L Krauss2, Kristina G Hultén1
1Department of Pediatrics, Section of Infectious Diseases,Baylor College of Medicine and Texas Children's Hospital,Houston, Texas.
Insights
Antiseptic tolerance genes are common in bloodstream bacteria, especially coagulase-negative staphylococci (CoNS). These genes are linked to hospital-acquired infections in CoNS and Staphylococcus aureus.
Area of Science:
- Microbiology
- Infectious Diseases
- Clinical Science
Background:
- Antiseptic tolerance (AT) genes (smr and qacA/B) in Staphylococcus aureus are linked to nosocomial infections.
- AT genes are also found in coagulase-negative staphylococci (CoNS) and enterococci, but their prevalence is less studied.
Purpose of the Study:
- To determine the frequency of AT genes in bloodstream isolates of S. aureus, CoNS, and enterococci at Texas Children's Hospital (TCH).
Main Methods:
- Collected and analyzed banked CoNS, S. aureus, and enterococci isolates from blood cultures at TCH.
- Utilized polymerase chain reaction (PCR) to detect smr and qacA/B genes.
- Reviewed medical records for clinical data.
Main Results:
- 80.6% of CoNS isolates carried AT genes, compared to 37% of S. aureus and 43.8% of Enterococcus faecalis.
- AT genes in CoNS were strongly associated with nosocomial infections (P < .001).
- In S. aureus, AT genes correlated with nosocomial infection, central-line-associated bloodstream infection (CLABSI), and recent hospitalizations.
Conclusions:
- Antiseptic tolerance is prevalent in bloodstream staphylococci and E. faecalis at TCH.
- The healthcare environment likely contributes to AT in staphylococci, particularly CoNS, which are frequently associated with nosocomial infections.
Objective:
The smr and qacA/B genes in Staphylococcus aureus confer tolerance to antiseptics and are associated with nosocomial acquisition of infection and underlying medical conditions. Such antiseptic tolerance (AT) genes have also been reported in coagulase-negative staphylococci (CoNS) and enterococci, however, few data are available regarding their prevalence. We sought to describe the frequency of AT genes among bloodstream isolates of S. aureus, CoNS and enterococci at Texas Children's Hospital (TCH).
Methods:
Banked CoNS, S. aureus and enterococci isolated from blood cultures collected bewteen October 1, 2016, and October 1, 2017, were obtained from the TCH clinical microbiology laboratory. All isolates underwent polymerase chain reaction (PCR) assay for the qacA/B and smr genes. Medical records were reviewed for all cases.
Results:
In total, 103 CoNS, 19 Enterococcus spp, and 119 S. aureus isolates were included in the study, and 80.6% of the CoNS possessed at least 1 AT gene compared to 37% of S. aureus and 43.8% of E. faecalis isolates (P < .001). Among CoNS bloodstream isolates, the presence of either AT gene was strongly associated with nosocomial infection (P < .001). The AT genes in S. aureus were associated with nosocomial infection (P = .025) as well as the diagnosis of central-line-associated bloodstream infection (CLABSI; P = .04) and recent hospitalizations (P < .001). We found no correlation with genotypic AT in E. faecalis and any clinical variable we examined.
Conclusions:
Antiseptic tolerance is common among bloodstream staphylococci and E. faecalis isolates at TCH. Among CoNS, the presence of AT genes is strongly correlated with nosocomial acquisition of infection, consistent with previous studies in S. aureus. These data suggest that the healthcare environment contributes to AT among staphylococci.
Related Concept Videos
01:08Prevalence and Incidence
Prevalence indicates the proportion of individuals in a population who have a specific disease or health...
01:25What is Population Genetics?
02:04Conservation of Small Populations
00:57Population Growth
00:30What are Populations and Communities?
02:39Gene Flow