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Persistent colonisation of potable water as a source of Mycobacterium avium infection in AIDS
C F von Reyn1, J N Maslow, T W Barber
1Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756.
Abstract:
The source of Mycobacterium avium infection in AIDS has not been identified and it is not known whether most patients with AIDS acquire the organism from recent infection or by reactivation of previous infection. As part of a prospective epidemiological study, we isolated multiple colonies of M avium from patients with AIDS and from potable water to which they had been exposed. All isolates were analysed with pulsed field gel electrophoresis (PFGE). As judged by PFGE, 29 (81%) of 36 patients were infected with one or more unique clinical strains of M avium. 7 patients (19%) were infected with three groups of common strains. Group 1 included 3 patients who lived in separate rural areas and had no common exposures apart from treatment at hospital A. The same strain was isolated repeatedly during 41 months from a recirculating hot water system at hospital A; residential water cultures were negative. Group 2 included 2 patients with no common exposures apart from treatment at hospital B; the same strain was isolated repeatedly over a period of 24 months from a recirculating hot water system at hospital B. Patients in groups 1 and 2 had numerous possible exposures to hospital hot water. Group 3 included 2 patients treated at the same methadone treatment facility. In an institution the hot water system may be persistently colonised with a particular strain of M avium. HIV-infected patients exposed to these water sources can develop disseminated M avium infection.
Insights
Mycobacterium avium infection in AIDS patients often originates from common strains found in hospital water systems. This study links specific M. avium strains in patients to contaminated recirculating hot water in healthcare facilities.
Area of Science:
- Microbiology
- Epidemiology
- Infectious Diseases
Background:
- The origin of Mycobacterium avium complex (MAC) infections in patients with Acquired Immunodeficiency Syndrome (AIDS) remains unclear, with uncertainty regarding recent acquisition versus reactivation of prior infection.
- Identifying the source of MAC is crucial for preventing disseminated infections in immunocompromised individuals.
Observation:
- A prospective epidemiological study investigated MAC in AIDS patients and their potable water exposure.
- Pulsed field gel electrophoresis (PFGE) was used to analyze M. avium isolates from patients and water sources.
Findings:
- PFGE revealed that 81% of 36 AIDS patients harbored unique clinical M. avium strains.
- 19% of patients were infected with common strains linked to hospital recirculating hot water systems at two separate hospitals.
- Specific M. avium strains were repeatedly isolated from hospital A's water system over 41 months and hospital B's over 24 months.
Implications:
- Recirculating hot water systems in institutions can be persistently colonized by specific M. avium strains.
- HIV-infected patients exposed to these contaminated water sources are at risk for disseminated M. avium infections.
- Findings suggest a significant role for hospital water systems as a reservoir for MAC transmission in AIDS patients.