Assessment of handwashing practices with chemical and microbiologic methods: Preliminary results from a prospective crossover study

Background: Handwashing (HW) by clinical staff is the single most important measure for preventing transmission of nosocomial infection (NI). The primary objectives of this study were to improve the motivation and awareness of the importance of HW practices among health care workers (HCWs) and to assess the effectiveness of a new chemical system in checking HW compliance. In addition, we evaluated the efficacy and tolerability of 2 soap solutions used during regular working hours by HCWs at our institution. Method: A preliminary short training course was performed to promote HW compliance and awareness. We chose 2 surgical wards at our 1200-bed teaching hospital. Sampling of hands was conducted weekly during routine activities of HCWs without advance warning. We used the staff list as a sampling frame to select subjects. Data were collected anonymously. On the basis of a crossover study design, a plain soap and one containing 4% chlorhexidine gluconate (CHG) were used alternatively in each ward for 4 consecutive months. Hand samples were evaluated with microbiologic cultures and with a commercially available kit that measures adenosine triphosphate (ATP) bioluminescence. As additional process indicators, we examined the amount of hand soap and CHG solution distributed and rate of NIs. Results: A total of 74 HCWs were evaluated for hand contamination. During the 4-month study, we found a significant reduction in colony-forming unit counts (P < .008) and ATP levels (P < .002) compared with baseline values. The results showed a positive correlation (r = 0.68, P < .0001) between the microbial counts detected by standard culture and ATP levels measured with the commercial kit. Plain soap (P < .003) was more effective than CHG in reducing colony-forming unit counts among HCWs in the vascular surgery ward. We documented a reduction in the NI rate and an increase in the consumption of soap and paper towels. Conclusion: HW compliance improved during the study period among HCWs. The method to measure ATP bioluminescence is simple and easy to perform and provides reliable results within a few minutes of sampling hands. It can be used extensively to test HW compliance among HCWs.