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Contaminated collection media as a cause of pseudoinfection
R H Schiappacasse1, S Ritter, C Schleis
1Department of Infection Control, St. Joseph's Mercy Hospital, Clinton Township, MI 48038.
Infection Control and Hospital Epidemiology
|December 1, 1994
Abstract:
Following the appearance of positive Gram's stains from sterile surgical cases, an investigation was begun. Nonviable but stainable bacteria were found in the gel-based transport media. The use of a cause-and-effect diagram helped to show the numerous items that affected the problem.
Insights
Positive Gram stains in sterile surgical cases were traced to nonviable bacteria in transport media. A cause-and-effect diagram identified factors contributing to this contamination issue.
Area of Science:
- Microbiology
- Clinical Diagnostics
- Quality Control
Background:
- Sterile surgical cases are critical for patient safety.
- Positive Gram stains from sterile sites indicate potential contamination.
- Investigating unexpected microbiological findings is essential.
Purpose of the Study:
- To identify the source of positive Gram stains in sterile surgical cases.
- To determine the nature of the observed bacterial presence.
- To analyze factors contributing to the contamination.
Main Methods:
- Microscopic examination of samples from sterile surgical cases.
- Analysis of gel-based transport media using Gram staining.
- Application of a cause-and-effect diagram (Ishikawa or fishbone diagram) to analyze potential sources.
Main Results:
- Nonviable but stainable bacteria were identified in the gel-based transport media.
- The investigation confirmed that the bacteria were not viable, thus not causing active infection.
- A cause-and-effect diagram highlighted multiple potential contributing factors to the presence of bacteria in the media.
Conclusions:
- The positive Gram stains originated from nonviable bacteria within the transport media, not active infections.
- Proper quality control of transport media is crucial to prevent false-positive results.
- Root cause analysis using tools like cause-and-effect diagrams can effectively identify sources of laboratory errors.