Spread of Pseudomonas fluorescens due to contaminated drinking water in a bone marrow transplant unit

Area of Science:

• Infectious Diseases
• Hospital Epidemiology
• Microbiology

Background:

• Pseudomonas infections pose significant risks for immunocompromised individuals, contributing to morbidity and mortality.
• Bone marrow transplant (BMT) units are particularly vulnerable to opportunistic infections due to profound immunosuppression.

Purpose of the Study:

• To investigate an outbreak of Pseudomonas fluorescens colonization in a BMT unit.
• To identify the source of P. fluorescens transmission and implement control measures.

Main Methods:

• Surveillance cultures of patients' pharyngeal swabs were performed weekly.
• Environmental sampling of water sources within the BMT unit was conducted.
• Isolates were identified using cetrimide agar and characterized by antibiotic susceptibility and molecular typing (RAPD-PCR, PFGE).

Main Results:

• A sharp increase in P. fluorescens isolation from surveillance swabs was observed over one month.
• Nine patients were colonized, with six developing febrile neutropenia.
• P. fluorescens was identified in drinking water from a contaminated chiller unit; other environmental samples were negative.
• Identical P. fluorescens strains were confirmed across patient and water isolates via molecular typing.

Conclusions:

• Contaminated bottled water dispensers can be a source of Pseudomonas fluorescens transmission in high-risk healthcare settings.
• Removal of the contaminated dispenser eradicated the source and prevented further infections.
• Recommendations include avoiding such water supplies in high-risk areas or implementing rigorous microbiological monitoring.