Related Experiment Videos
Genotypic analysis of pseudoepidemic due to contamination of Hanks' balanced salt solution with Candida parapsilosis
S C Deresinski1, K V Clemons, C A Kemper
1Department of Medicine, Santa Clara Valley Medical Center, San Jose, California 95128, USA.
Abstract:
A cluster of isolates of Candida parapsilosis recovered from clinical specimens was demonstrated, by both classical and molecular epidemiological techniques, to have resulted from contamination in the laboratory. The source of the pseudoepidemic was a repeatedly utilized contaminated container of Hanks' balanced salt solution used in specimen processing. The patterns of restriction fragment length polymorphisms of DNA extracted from the clinical and environmental isolates were identical to each other but composed a newly identified unique C. parapsilosis DNA type.
Insights
A laboratory contamination, not a true Candida parapsilosis outbreak, was identified using molecular techniques. The source was a contaminated Hanks
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Candida parapsilosis is an opportunistic fungal pathogen causing infections, particularly in healthcare settings.
- Distinguishing true outbreaks from laboratory contamination is crucial for accurate patient management and infection control.
Purpose of the Study:
- To investigate a cluster of Candida parapsilosis isolates from clinical specimens.
- To determine the source and nature of the observed isolate cluster, differentiating between a true pseudoepidemic and laboratory error.
Main Methods:
- Classical microbiological techniques were employed for isolate characterization.
- Molecular epidemiological methods, including DNA extraction and restriction fragment length polymorphism (RFLP) analysis, were utilized.
- Environmental sampling and analysis were performed to identify the contamination source.
Main Results:
- A cluster of Candida parapsilosis isolates from clinical specimens was confirmed to be due to laboratory contamination.
- The contamination originated from a reusable container of Hanks' balanced salt solution used in specimen processing.
- DNA fingerprinting (RFLP) revealed identical patterns among clinical and environmental isolates, representing a unique Candida parapsilosis DNA type.
Conclusions:
- Laboratory procedures can lead to pseudoepidemics, mimicking true outbreaks of Candida parapsilosis.
- Rigorous quality control and aseptic techniques in laboratories are essential to prevent specimen contamination.
- The identification of a unique DNA type highlights the importance of molecular tools in tracing microbial sources.