Continuous chlorhexidine use and its impact on healthcare workers’ hands microbiota

Gisela Serra Rodrigues Costa; William Kazumassa Minami; Marcia Maria Baraldi; Amanda Luiz Pires Maciel; Cristiane Luiz Pires Schmitt; Sânia Alves dos Santos; Ana Paula Marchi; Camila Fonseca Rizek; Maria Eduarda Rufino Zani; Letícia Muniz Souza; Silvia Figueiredo Costa; Ícaro Boszczowski

doi:10.5455/EJMID.20241005122246

Abstract
Aim: To assess chlorhexidine (CHG) susceptibility among resident microbiota from hands of healthcare workers (HCWs) after a period of continuous CHG soap use for handwashing compared to plain soap.
Methods: Before-after crossover study in a not-for-profit private tertiary care hospital in São Paulo, Brazil from April 2016 to April 2018. We alternated control (plain soap) and intervention periods (CHG soap) in selected wards at intervals of four to eight months. We collected the HCWs hand sample before each period swap along with the application of a questionnaire about product tolerability. MALDI-TOF was used for species identification, and CHG susceptibility testing was performed with agar dilution.
Results: We obtained 259 samples yielding 422 isolates and 24 different genera. We observed increased MIC values for Staphylococcus epidermidis in the intervention (MIC50 4 mg/L and MIC90 16 mg/L) compared to baseline and control groups (MIC50 2 mg/L and MIC90 4 mg/L). We detected a higher proportion of gram-negative bacteria and Candida spp. in the intervention than in the baseline group (23% vs 49%; RR 1.91 [CI95% 1.27-2.89]; P=0.001). Skin dryness was more frequent in the intervention group, and better skin comfort was reported within control group.
Conclusion: The MIC values for the most prevalent gram-positive bacteria in HCWs’ hands tended to increase after continuous CHG use. CHG´s handwashing practice seems to modify the microbiological profile and increase skin intolerance among HCWs.

Key words: chlorhexidine resistance, infection control