Clinical impact of and microbiological risk factors for qacA/B positivity in ICU-acquired ST5-methicillin-resistant SCCmec type II Staphylococcus aureus bacteremia.

Abstract

Concern about resistance to chlorhexidine has increased due to the wide use of the latter. The impact of the qacA/B and smr chlorhexidine tolerance genes on the outcome of methicillin-resistant Staphylococcus aureus (MRSA) infections is unclear. We evaluated the prevalence and clinical impact of, and microbiological risk factors for, qacA/B tolerance in MRSA bacteremia. MRSA bacteremia that occurred more than two days after intensive care unit admission between January 2009 and December 2018 was identified from a prospective cohort of S. aureus bacteremia in a tertiary-care hospital from South Korea. A total of 183 MRSA blood isolates was identified, and the major genotype found was ST5-MRSA-II (87.4%). The prevalences of qacA/B and smr were 67.2% and 3.8%, respectively. qacA/B-positive isolates were predominantly ST5-MRSA-II (96.7% [119/123]), the dominant hospital clone. In a homogenous ST5-MRSA-II background, qacA/B positivity was independently associated with septic shock (aOR, 4.85), gentamicin resistance (aOR, 74.43), and non-t002 spa type (aOR, 74.12). qacA/B positivity was found to have decreased significantly in ST5-MRSA-II in association with a decline in qacA/B-positive t2460, despite the increasing use of chlorhexidine since 2010 (P < 0.001 for trend). Continuous surveillance of the qac genes, and molecular characterization of their plasmids, are needed to understand their role in MRSA epidemiology.

• Authors: Haein Kim, Sunghee Park, Hyeonji Seo, Hyemin Chung, Eun Sil Kim, Heungsup Sung, Mi-Na Kim, Seongman Bae, Jiwon Jung, Min Jae Kim, Sung-Han Kim, Sang-Oh Lee, Sang-Ho Choi, Yang Soo Kim, Yong Pil Chong
• Journal: Scientific reports (Sci Rep) Vol. 12 Issue 1 Pg. 11413 (07 06 2022) ISSN: 2045-2322 [Electronic] England
• PMID: 35794229 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2022. The Author(s).

Chemical References

• Bacterial Proteins
• Membrane Transport Proteins
• Chlorhexidine

Topics

• Bacteremia (drug therapy, epidemiology, microbiology)
• Bacterial Proteins (genetics)
• Chlorhexidine (pharmacology)
• Humans
• Intensive Care Units
• Membrane Transport Proteins (genetics)
• Methicillin Resistance
• Methicillin-Resistant Staphylococcus aureus (genetics)
• Microbial Sensitivity Tests
• Prospective Studies
• Risk Factors
• Staphylococcal Infections (drug therapy, epidemiology, microbiology)
• Staphylococcus aureus (genetics)