Prevalence of qacA/B Genes and Mupirocin Resistance Among Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates in the Setting of Chlorhexidine Bathing Without Mupirocin. (2nd February 2016)

• Record Type: Journal Article
• Authors: Warren, David K.; Prager, Martin; Munigala, Satish; Wallace, Meghan A.; Kennedy, Colleen R.; Bommarito, Kerry M.; Mazuski, John E.; Burnham, Carey-Ann D.
• Is Part Of: Infection control and hospital epidemiology. Volume 37:Number 5(2016)
• Page Start: 590
• Page End: 597
• Publication Date: 2016-02-02
• Subjects: Nosocomial infections -- Epidemiology -- Periodicals; Health facilities -- Sanitation -- Periodicals; Hospital buildings -- Sanitation -- Periodicals; Cross Infection -- Periodicals; Epidemiology -- Periodicals; Hospitals -- Periodicals; Infection Control -- Periodicals; 614.44
• DOI: 10.1017/ice.2016.1
• Languages: English
• ISSNs: 0899-823X

Abstract

Abstract : OBJECTIVE: We aimed to determine the frequency of qacA/B chlorhexidine tolerance genes and high-level mupirocin resistance among MRSA isolates before and after the introduction of a chlorhexidine (CHG) daily bathing intervention in a surgical intensive care unit (SICU). DESIGN: Retrospective cohort study (2005–2012) SETTING: A large tertiary-care center PATIENTS: Patients admitted to SICU who had MRSA surveillance cultures of the anterior nares METHODS: A random sample of banked MRSA anterior nares isolates recovered during (2005) and after (2006–2012) implementation of a daily CHG bathing protocol was examined for qacA/B genes and high-level mupirocin resistance. Staphylococcal cassette chromosome mec (SCC mec ) typing was also performed. RESULTS: Of the 504 randomly selected isolates (63 per year), 36 (7.1%) were qacA/B positive (+) and 35 (6.9%) were mupirocin resistant. Of these, 184 (36.5%) isolates were SCCmec type IV. There was a significant trend for increasing qacA/B ( P =.02; highest prevalence, 16.9% in 2009 and 2010) and SCC mec type IV ( P <.001; highest prevalence, 52.4% in 2012) during the study period. qacA/B (+) MRSA isolates were more likely to be mupirocin resistant (9 of 36 [25%] qacA/B (+) vs 26 of 468 [5.6%] qacA/B (−); P =.003). CONCLUSIONS: A long-term, daily CHG bathing protocol was associated with a change in the frequency of qacA/B genes in MRSA isolates recovered from the anterior nares over an 8-year period. This change in the frequency of qacA/B genes is most likely due to patients in those years being exposed in prior admissions. Future studies need to further evaluate the implications of universal CHG daily bathing on MRSA qacA/B genes among hospitalized patients. Infect Control Hosp Epidemiol 2016;37:590–597