Microbiological methods for assessing handwashing practice in hygiene behaviour studies.

Personal hygiene, especially handwashing, is frequently mentioned as an important aspect of diarrhoeal disease prevention in water and sanitation programmes. Handwashing practice is difficult to assess but the microbiological analysis of hands shows promise as an indicator of this behaviour. Most methods for isolating bacteria from the hands have been developed for use in hospitals in order to investigate the spread of nosocomial infections. However, reliable and inexpensive methods which need only limited expertise are needed for use in developing countries where diarrhoeal diseases remain a major health risk. Techniques for sampling hands and bacteriological analysis methods are discussed with special emphasis on practical considerations for conducting tests in developing countries. Several studies have used these methods successfully and have investigated hygiene behaviour and how living conditions affect behaviour and the role of hands in diarrhoeal disease transmission. We recommend the use of impression plates for isolating faecal indicator bacteria from the hands and also recommend faecal streptococci as an indicator of faecal contamination.