Reduced susceptibility to chlorhexidine among staphylococcus aureus isolates in israel: Phenotypic and genotypic tolerance

Maya Azrad, Chen Shmuel, Tamar Leshem, Zohar Hamo, Moti Baum, Assaf Rokney, Keren Agay-Shay, Avi Peretz

Research output: Contribution to journalArticlepeer-review


Antiseptic use for body decolonization is the main activity applied to prevent healthcare-associated infections, including those caused by S. aureus. Consequentially, tolerance to several antiseptics such as chlorhexidine gluconate (CHG) has developed. This study aimed to estimate the prevalence of CHG tolerance among S. aureus strains in Israel and to evaluate factors that may affect this tolerance. Furthermore, it tested the associations between phenotypic and genotypic CHG tolerance. S. aureus strains (n = 190) were isolated from clinical samples of patients admitted to various medical institutions in Israel. Phenotypic susceptibility to CHG was assessed by determining minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Genotypic tolerance was detected using real-time PCR for detection of qac A/B genes. MIC for the antibiotic mupirocin was determined using the Etest method. Presence of the Panton–Valentine Leucocidin (pvl) toxin, mecA and mecC genes was detected using an eazyplex® MRSAplus kit (AmplexDiagnostics GmbH, Gars, Germany). CHG tolerance was observed in 13.15% of the isolates. An association between phenotypic and genotypic tolerance to CHG was observed. Phenotypic tolerance to CHG was associated with methicillin resistance but not with mupirocin resistance. Additionally, most of the CHG-tolerant strains were isolated from blood cultures. In conclusion, this work shed light on the prevalence of reduced susceptibility to CHG among S. aureus strains in Israel and on the characteristics of tolerant strains. CHG-tolerant strains were more common than methicillin-resistant ones in samples from invasive infections. Further research should be performed to evaluate risk factors for the development of CHG tolerance.

Original languageEnglish
Article number342
Issue number3
StatePublished - 23 Mar 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.


  • Chlorhexidine
  • Genotypic and phenotypic susceptibility
  • Healthcare-associated infections
  • Reduced susceptibility
  • S. aureus

ASJC Scopus subject areas

  • Microbiology
  • Biochemistry
  • General Pharmacology, Toxicology and Pharmaceutics
  • Microbiology (medical)
  • Infectious Diseases
  • Pharmacology (medical)


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