BACKGROUNDHealthcare-associated infections (HAIs) are an important issue that needs to be continuously addressed in healthcare institutions, and healthcare professionals (HCPs) are expected to strengthen educational programmes on infection prevention. Although the incidence of HAIs in Japan has been decreasing, the actual state of knowledge on infection prevention among HCPs remains unclear.AIMTo clarify the actual infection prevention knowledge of HCPs in Japan.METHODSThe study participants were 1158 HCPs working in healthcare institutions with frequent contact with patients (283 doctors, 591 nurses, 115 physical therapists, 97 radiologists, and 72 medical technologists). HCPs described the infection prevention behaviours they consciously adhered to via an online self-administered questionnaire. Data were analysed by text mining. Categories were extracted from the responses to reveal HCPs' infection prevention knowledge.FINDINGSMore than half of the participants (64.9%) were aged > 40 years, and 48.1% had over 20 years of clinical experience. The majority of the participants were nurses (51.0%), 43.9% had a bachelor's degree, and 56.6% were female. Seven categories regarding infection prevention knowledge were extracted: "performing hand hygiene and gargling," "wearing personal protective equipment," "strengthening one's immunity," "protecting oneself and patients from infection," "distinguishing clean and unclean zones," "actions to prevent transmission to others in daily life activities," and "maintaining distance from others."CONCLUSIONThese results suggest that most HCPs working in healthcare settings in Japan prioritize and adhere to standard precautionary measures, and that the low incidence of HAIs may be influenced by perceptions of the knowledge of "handwashing and gargling" among HCPs.