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Nosocomial mycobacterial pseudoinfection in a Georgia hospital
Abstract:
Nosocomial pseudoepidemics may be detected when clustering of pseudoinfections occur or when artificial clusters of real infection are observed. Nontuberculous mycobacteria were reportedly isolated from specimens obtained from seven patients at one hospital from October 1980 to January 1981. Because the patients' clinical illnesses were not uniformly consistent with mycobacterial disease, we hypothesized that pseudoinfections had occurred and searched for a common source of contamination. The investigation suggested that specimen contamination was associated with one microbiology laboratory technician: 6 of 22 (27%) specimens processed by that person were positive compared with 1 of 103 (1%) specimens processed by the other five technicians. However, a specific mechanism of contamination was not identified. Nosocomial pseudoepidemics associated with false infections should be suspected and investigated when clinical features and laboratory findings do not agree.
Insights
Nosocomial pseudoepidemics, or false infection outbreaks, can occur in hospitals. This study identified a laboratory technician as a likely source of contamination leading to a pseudoepidemic of nontuberculous mycobacteria.
Area of Science:
- Medical Microbiology
- Infectious Disease Epidemiology
- Hospital-Acquired Infections
Background:
- Nosocomial pseudoepidemics arise from either pseudoinfections or artificial clusters of true infections.
- Nontuberculous mycobacteria (NTM) were isolated from seven patients at a single hospital between October 1980 and January 1981.
- Clinical presentations did not consistently align with mycobacterial disease, prompting an investigation into potential pseudoinfections.
Purpose of the Study:
- To investigate the cause of a suspected nosocomial pseudoepidemic.
- To identify a potential common source of contamination for NTM isolates.
- To determine if laboratory procedures contributed to the observed pseudoepidemic.
Main Methods:
- Retrospective analysis of NTM isolates from patient specimens.
- Comparison of specimen contamination rates based on laboratory personnel processing.
- Epidemiological investigation to identify potential sources of contamination.
Main Results:
- A significant association was found between specimen processing by one specific microbiology laboratory technician and positive NTM results.
- 27% of specimens processed by the implicated technician were positive, compared to 1% for other technicians.
- No specific mechanism of contamination was identified, despite the strong association with one technician.
Conclusions:
- The investigation strongly suggested that specimen contamination linked to a single laboratory technician caused the nosocomial pseudoepidemic.
- Clinical and laboratory discrepancies should prompt suspicion and investigation of pseudoepidemics.
- Enhanced laboratory quality control measures are crucial to prevent false infection outbreaks.