A proactive approach to prevention of health care–acquired Legionnairesʹ disease: The Allegheny County (Pittsburgh) experience

Background The Allegheny County Health Department (ACHD) in Pennsylvania distributed the first guidelines for prevention and control of health care–acquired Legionnairesʹ disease (LD) by 1995. The proactive approach advocated in the guidelines differed notably from that of the Centers for Disease Control and Prevention (CDC) by recommending routine environmental testing of the hospital water distribution system even when cases of health care–acquired Legionnairesʹ disease had never been identified. Objectives Our purpose was to (1) evaluate the impact of the ACHD guidelines on the Legionella diagnostic and preventive practices of health care facilities in Allegheny and surrounding counties and (2) compare the incidence of health care–acquired LD before and after issuance of the ACHD guidelines. Methods CDC case reports of LD from 1991 to 2001 were tabulated and compiled by the ACHD Infectious Disease Unit and the Association for Professionals in Infection Control and Epidemiology, Inc, Three Rivers Chapter. A survey was distributed to 110 hospitals and long-term care facilities in the region. The results were analyzed as occurring either in the preguideline period (1991-1994) or postguideline period (1995-2001). Results A significant decrease in the number of health care–acquired cases was demonstrated between the preguideline (33%) and postguideline (9%) periods (P = .0001). In contrast, community-acquired cases increased from 67% pre guideline to 91% post guideline. A total of 71% of the facilities were colonized with Legionella. Disinfection of the water distribution system was initiated by 44% of facilities. Use of urinary antigen testing significantly increased from 40% pre guideline to 79% post guideline (P = .0001). Conclusions Health care–acquired LD declined significantly after the issuance of guidelines for prevention and control of health care–acquired LD. The decline was associated with health care facilities performing routine environmental monitoring of their water distribution systems followed by the initiation of disinfection methods if indicated. Two unanticipated benefits were (1) cases of LD in the community and long-term care facilities were uncovered as a result of increased availability of Legionella tests and (2) litigation and unfavorable publicity involving ACHD hospitals ceased.