Background: There is insufficient evidence for daily chlorhexidine bathing to reduce nosocomial spread
of carbapenem-resistant Acinetobacter baumannii (CRAB) in endemic situations.
Methods: An interrupted time series study was performed to evaluate the effect of daily chlorhexidine
bathing on the acquisition of CRAB in a medical intensive care unit (ICU) with CRAB endemicity. There
was a 14-month control period and 12-month chlorhexidine bathing period. Segmented Poisson
regression analysis was performed to assess the impact of chlorhexidine bathing on the level and trend of
the series of prevalence rates and incidence density. Also, chlorhexidine susceptibility testing was performed
on CRAB isolates collected during the chlorhexidine bathing period.
Results: There was a 51.8% reduction of CRAB acquisition rates after an introduction of daily chlorhexidine
bathing (44.0 vs 21.2 cases/1,000 at-risk patient days, P < .001). There was a significant reduction in
the level (0.604; 95% CI, 0.904 to 0.305; P < .001) of incidence density of CRAB, whereas there was
no significant change in both level and trend of CRAB prevalence rates. Minimum inhibitory concentration
of chlorhexidine against a total of 98 CRAB isolates ranged from 8-64 mg/mL.
Conclusion: Daily chlorhexidine bathing significantly reduces the acquisition of CRAB in a medical ICU
with CRAB endemicity