BackgroundHealth care associated infections (HAIs) are a source of concern worldwide. No health service in any country can be considered HAI risk-free. However, there is scarcity of data on the risks to which both patients and health workers are subject in non-hospital settings. The aim of this study was to identify issues that determine the adherence of professionals to precautions for preventing transmission of microorganisms in primary health care.MethodThis was a qualitative study, using focus groups of primary health care staff, in two Brazilian municipalities. The data were analysed using content analysis.ResultsFour focus groups were conducted with 20 professionals (11 community health workers, 5 nursing assistants and 4 nurses), and the analysed content was organized into four thematic categories. These categories are: low risk perception, weaknesses in knowledge, insufficient in-service training and infrastructure limitations.Participants expressed their weaknesses in knowledge of standard and transmission based precautions, mainly for hand hygiene and tuberculosis. A lack of appropriate resources and standardization in sharps disposal management was also highlighted by the participants.ConclusionThe study points out the need to provide in-service training for professionals on the transmission of microorganisms in primary health care to ensure adequate level of risk perception and knowledge. Further recommendations include investment to improve infrastructure to facilitate adherence to precautions and to minimize the risk of disease transmission for both patients and health care workers.