Introduction:
Hand hygiene is very often omitted or improperly performed by healthcare workers. Knowledge of hygienic procedures and guidelines may play a pivotal role in the effectiveness of healthcare workers hand disinfection.

Aim of the research:
The assessment of potential correlation between theoretical knowledge of guidelines to hand hygiene and the frequency of theoretical and practical training in hand hygiene on the microbiological effectiveness of hand disinfection.

Material and methods:
The study was conducted among 200 healthcare workers. For the assessment of the healthcare workers’ knowledge of hand hygiene a self-designed questionnaire was used. The microbiological effectiveness of hand hygiene was performed by collecting pre- and post-disinfected handprints. We assumed that a decrease in bacteria levels on the hands after disinfection indicates the effectiveness of hand hygiene.

Results:
The analysis of microbiological tests demonstrated that the levels of bacteria on healthcare workers’ hands differ according to theoretical knowledge of guidelines for hand hygiene. The group with better results in the knowledge test had a lower number of microorganisms on their hands after hand disinfection. Participants had many problems with identification of situations in which hand disinfection is obligatory. Among wrong answers the most common were: belief that gloves can replace hand disinfection (31%), and lack of knowledge that hand rub must be performed before contact with the patient (30%). More than one theoretical training per year was associated with better hand disinfection efficiency.

Conclusions:
Theoretical knowledge of hand hygiene affects compliance with hand hygiene recommendations and results in better microbiological effectiveness of performed procedures. The fact that HCWs are not aware in which moments they should disinfect their hands highlight the need for designing and implementation of adequate multi-modal strategies for improvement of hand hygiene.