Skin disease presenting as an outbreak of pseudobacteremia in a laboratory worker

Area of Science:

• Clinical Microbiology
• Infectious Disease Epidemiology

Background:

• Pseudobacteremia outbreaks pose a diagnostic challenge.
• Contamination of blood cultures can lead to misdiagnosis and inappropriate treatment.

Purpose of the Study:

• To identify the source and cause of a pseudobacteremia outbreak.
• To evaluate laboratory procedures contributing to contamination.

Main Methods:

• Investigated an outbreak of bloodstream infections.
• Performed bacterial isolate typing (M and T types for GAS, phage profiling for MSSA).
• Reviewed laboratory protocols for blood culture handling.

Main Results:

• Identified Streptococcus pyogenes (group A streptococci [GAS]) and methicillin-susceptible Staphylococcus aureus (MSSA) as causative agents.
• Traced contamination to improper venting of aerobic blood culture bottles by an infected laboratory worker.
• Identified procedural breaches including inadequate personal protective equipment and unsafe venting techniques.

Conclusions:

• Improper laboratory procedures, specifically bottle venting, led to patient contamination.
• Strict adherence to aseptic techniques and biosafety protocols is crucial to prevent pseudobacteremia.
• Prompt identification and treatment of the source case resolved the outbreak.