304. Unexpected high prevalence of qacA/B and smr genes among Staphylococcus spp isolates from individuals attending a Sexually Transmitted Infections (STI) clinic.
Session: Poster Abstract Session: HAI: MSSA, MRSA, and other Gram-Positives
Thursday, October 27, 2016
Room: Poster Hall
Posters
  • qacAB poster V2.pdf (2.7 MB)
  • Background: Plasmid-borne qacA/B and smr genes encode for multidrug efflux pumps and are associated with reduced susceptibility to quaternary ammonium compounds (QAC) and chlorhexidine (CHX). As part of a prevalence survey of Staphylococcus aureus (SA) carriage among people attending a STI clinic, we analyzed the prevalence of qac A/B and smr genes among Staphylococcus spp isolates. Methods: Following Ethics Board approval, written informed consent was obtained and swabs from nares, throat, axilla, groin, perineum-perianal, vaginal, upper back and interdigital web spaces were collected from a STI clinic population over a 5 month period. Following broth enrichment, SA and coagulase negative staphylococci (CNS) isolates were identified using standard laboratory procedures. Identification of qac A/B and smr genes was done with a novel multiplex PCR assay with 6 targets: 16s rRNA, nuc (to distinguish SA from CNS), qacA/B, smr, mupA and mecA. Results: A sample of 265 Staphylococcus spp isolates from 204 individuals was analyzed; 155 (58.5%) were methicillin-susceptible SA (MSSA), 94 (35.4%) were methicillin-susceptible CNS (MS-CNS) and 16 (6%) methicillin-resistant CNS (MR-CNS), no MRSA isolates were found. The overall prevalence of any of qacA/B and/or smr genes was 12.8%; the highest prevalence was among MR-CNS isolates compared to MS-CNS (56.2%, 9/16 vs 20.2%, 19/94; p <0.01) followed by 3.8% (6/155) in MSSA. Combinations of qacA/B and smr genes were only seen among CNS isolates, more commonly in MS-CNS vs. MR-CNS (8.5%, 8/94 vs. 1/16, 6.2%; p=NS). Positivity of the mup gene was only observed in 3 isolates (0.1%), always in combination with other genes.

    Conclusion: We found a high prevalence of qacA/B genes in Staphylococcus spp isolates among people attending a STI clinic compared to very low rates (0-2%) reported in community ambulatory settings. This is one of the first studies documenting the presence of qacA/B and smr genes in staphylococci in a STI population. Genes that may confer resistance to QACs and CHX among isolates in an ambulatory setting are of concern since they may serve as an unrecognized reservoir for their introduction into the hospital setting. Further studies in other STI clinic populations would be of value to corroborate our findings.

    Alejandra Ugarte Torres, MD1, Johanna Delongchamp, MSc2, Linda Ward, MLT2,3, Joann Mcclure, BSc2, Kunyan Zhang, MD, PhD2,4,5, Thomas Louie, MD2,3,6, Judy Macdonald, MD7,8, Daniel Gregson, MD5,9,10, Angel Chu, MD2,11, Oscar Larios, MD2,5, Ron Read, MD, PhD, FRCPC2,5,11 and John Conly, MD2,3,5,6,12, (1)Medicine, Infectious Diseases, Alberta Health Services, Calgary, AB, Canada, (2)Microbiology, Infectious Diseases and Immunology, University of Calgary, Calgary, AB, Canada, (3)Infection Prevention and Control, Alberta Health Services, Calgary, AB, Canada, (4)Pathology and Laboratory Medicine, Alberta Health Services, Calgary, AB, Canada, (5)Snyder Institute for Chronic Diseases, Calgary, AB, Canada, (6)Pathology and Laboratory Medicine, University of Calgary, Calgary, AB, Canada, (7)Public Health, Alberta Health Services, Calgary, AB, Canada, (8)Community Health Sciences, Cumming School of Medicine, Calgary, AB, Canada, (9)University of Calgary, Calgary, AB, Canada, (10)Calgary Laboratory Services, Calgary, AB, Canada, (11)STI Clinic, Alberta Health Services, Calgary, AB, Canada, (12)Medicine, Alberta Health Services, Calgary, AB, Canada

    Disclosures:

    A. Ugarte Torres, None

    J. Delongchamp, None

    L. Ward, None

    J. Mcclure, None

    K. Zhang, None

    T. Louie, None

    J. Macdonald, None

    D. Gregson, None

    A. Chu, None

    O. Larios, None

    R. Read, None

    J. Conly, None

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