Objectives To investigate the contamination of legionella pneumophila (LP) and sanitary administration in recycled water from central air conditioning systems and shower water in large hotels of an urban district in Beijing and to provide scientific basis for controlling legionella contamination efficiently.

Methods The contamination of LP in the recycled water of central air conditioning systems was detected in 29 three-star and above hotels selected by random sampling in this area and the sanitary administration was investigated by questionnaire survey.

Results LP was isolated from 17 hotels (58.62%); the positive rate of LP was 40% in cooling water and was 24.1% in shower water. The predominant serum type of isolated strains was LP 1(50%), which was 14.3% in strains isolated from shower water. The positive rate of LP in five-star hotels were lower than that in three-star and four-star hotels. Factors influencing the contamination of legionella were the frequency of legionella detection in cooling water and the sanitation in engine rooms.

Conclusions The situation of LP contamination was not optimistic. The sanitary administration of central air conditioning system should be evaluated from multiple aspects and the targeted health supervision and monitoring should be strengthened.It is necessary to improve legislation and strengthen punishment as well as training to prevent the outbreak of legionella contamination.