Pseudobacteremia due to contaminated alcohol swabs

Area of Science:

• Clinical Microbiology
• Infectious Diseases
• Laboratory Science

Background:

• Automated radiometric blood culture systems are widely used for pathogen detection.
• Bacillus species can act as both significant pathogens and common laboratory contaminants.
• Contamination events can impact diagnostic accuracy and patient care.

Purpose of the Study:

• To investigate an outbreak of Bacillus species contamination in an automated radiometric blood culture system.
• To identify the source of Bacillus spores contaminating blood cultures.
• To discuss the implications of Bacillus species in clinical laboratory settings.

Main Methods:

• Monitoring of an automated radiometric blood culture system over a 19-day period.
• Isolation and identification of Bacillus species from blood cultures.
• Traceback investigation to determine the source of contamination.

Main Results:

• Fifteen isolates of Bacillus species were recovered during the study period.
• The contamination outbreak was traced to alcohol-resistant spores found in cotton used for disinfecting blood culture bottles.
• The cotton's alcohol resistance allowed spore survival and subsequent contamination.

Conclusions:

• Cotton disinfection materials can harbor alcohol-resistant Bacillus spores, leading to contamination in blood culture systems.
• Bacillus species pose a dual threat as potential pathogens and persistent laboratory contaminants.
• Strict quality control of consumables is crucial to prevent such outbreaks.