title: Multicenter Evaluation of MRSASelect II Chromogenic Agar for Identification of Methicillin-Resistant Staphylococcus aureus from Wound and Nasal Specimens.
abstract: Hospitals strive to reduce methicillin-resistant Staphylococcus aureus (MRSA) prevalence via active surveillance of inpatient populations. Rapid and inexpensive screening methods are utilized when molecular methods are not operationally feasible. In this multisite clinical trial, the utility of Bio-Rad's MRSASelect II was evaluated for MRSA identification from remnant nares and wound swabs. The prevalence of MRSA was 11.1% (n = 1,384) from nares samples and 18.1% (n = 842) from wound samples. MRSASelect II had an overall concordance of 95.4% (confidence interval [CI] = 94.5% to 96.2%) compared to a broth-enriched reference standard. Comparisons between results, stratified by examination times, exhibited a nonsignificant trend toward increased positivity at prolonged incubation times. Cefoxitin screening of colonies directly from MRSASelect II was 96.7% (95.8% to 97.3%) concordant compared to testing of colonies following broth enrichment. A comparison of MRSASelect and MRSASelect II revealed no statistical differences; however, the latter exhibited earlier positivity, greater selectivity, and more intense indicator staining, which resulted in facilitated differentiation of positive results. MRSASelect II agar is a simple, rapid, and robust method to routinely screen patients for MRSA colonization without the need for additional testing.
authors.affiliation: Geisinger Health System, Danville, Pennsylvania, USA drhernandez@geisinger.edu.
authors.forename: Diana R
authors.identifier: http://orcid.org/0000-0003-1377-4438
authors.initials: DR
authors.lastname: Hernandez
authors.affiliation: University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: Duane W
authors.initials: DW
authors.lastname: Newton
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Ledeboer
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Blake
authors.identifier: http://orcid.org/0000-0002-4111-048X
authors.initials: B
authors.lastname: Buchan
authors.affiliation: University of Michigan Health System, Ann Arbor, Michigan, USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Young
authors.affiliation: University of Arizona, Tucson, Arizona, USA.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Clark
authors.affiliation: Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Connoly
authors.affiliation: Geisinger Health System, Danville, Pennsylvania, USA.
authors.forename: Donna M
authors.initials: DM
authors.lastname: Wolk
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002863:Chromogenic Compounds; D052978:Disk Diffusion Antimicrobial Tests; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests / Q000379:methods* / Q000592:standards; D009296:Nasal Cavity / Q000382:microbiology*; D010641:Phenotype; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology*; D057188:Workflow; D014947:Wounds and Injuries / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D002863:Chromogenic Compounds