Legionella pneumophila contamination of hospital dishwashers

Area of Science:

• Microbiology
• Healthcare Epidemiology
• Infectious Disease Control

Background:

• Legionella species are waterborne bacteria that can cause Legionnaires' disease, a severe form of pneumonia.
• Healthcare facilities present unique challenges for controlling waterborne pathogens due to complex plumbing systems and vulnerable patient populations.

Purpose of the Study:

• To investigate the presence and genetic relatedness of Legionella spp. in a tertiary hospital's water system.
• To identify potential reservoirs contributing to Legionella contamination within the healthcare environment.

Main Methods:

• Environmental sampling of taps and ward dishwashers in a tertiary hospital.
• Isolation and identification of Legionella species.
• Genotyping of Legionella pneumophila isolates using repetitive-element polymerase chain reaction (rep-PCR).

Main Results:

• Legionella species were successfully isolated from both taps and ward dishwashers.
• Conditions conducive to Legionella growth were identified in the investigated areas.
• All Legionella pneumophila serogroup 6 isolates from taps and dishwashers exhibited identical genetic profiles via rep-PCR.

Conclusions:

• Contaminated tap piping likely served as the source for Legionella in ward dishwashers.
• Ward dishwashers represent a potential reservoir for Legionella amplification and dissemination within healthcare facilities.
• These findings underscore the importance of monitoring and controlling Legionella in hospital water systems to prevent healthcare-associated infections.