In vitro, elusidation of the mechanism by which chlorhexidine induce to cross-resistance of various antimicrobial agents in Pseudomonas aeruginosa

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K19034
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 58050:Fundamental of nursing-related
• Research Institution: Tohoku Medical and Pharmaceutical University
• Principal Investigator: Kawamura Masato 東北医科薬科大学, 薬学部, 講師 (20524581)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 消毒薬 / 緑膿菌 / 耐性菌 / 薬剤耐性菌（AMR） / 抗菌薬 / 医療関連感染

Outline of Final Research Achievements

This study investigated the cross-resistance of antibiotics in P. aeruginosa that exposed to chlorhexidine gluconate (CHG). The testes strains were sub cultured in CHG-containing medium, and the MIC of CHG increased up to 256 μg/mL. Among these clinical isolates exposured to CHG, P. aeruginosa was confirmed to be cross-resistant of ciprofloxacin (CPFX) (MIC; 1 μg/mL). Some P. aeruginosa strains showed no resistance of amikacin (AMK) but showed a 3-tube increase in the MIC. However, no change was observed in the MIC of meropenem of β-lactam drug. In the strains that acquired cross-resistance to quinolone antimicrobials, the expression level of mexCD-oprD, which encodes one of the efflux pumps, increased 1.9 ± 1.1 (mean ± SD) times. These results suggest that inappropriate use of disinfectant concentrations may lead to the emergence of quinolone-resistant P. aeruginosa.

Free Research Field

感染制御　感染症治療　感染対策

Academic Significance and Societal Importance of the Research Achievements

カルバペネム系薬、キノロン系薬およびアミノグリコシド系薬に耐性を獲得したMDRPの出現は、抗菌薬の不適切使用が一因にあると考えられてきた。しかし、消毒薬のCHGに抵抗性を獲得したP. aeruginosaの一部は、キノロン系抗菌薬のCPFXに交差耐性を獲得した。この交差耐性獲得株は、主にMexCD-OprJの高発現が関与すると考えられてた。不適切な抗菌薬使用による薬耐性菌（AMR）の出現のみならず、CHGなどの消毒薬暴露によるAMR対策も講じる必要があると考えられた。