From the Guidelines
Culturing Coxiella burnetii is not recommended for routine diagnosis due to its highly infectious nature and the requirement for a biosafety level 3 (BSL-3) laboratory, and should only be performed in specialized laboratories with appropriate containment facilities 1.
Key Considerations for Coxiella burnetii Culture
- The process of culturing Coxiella burnetii is difficult, time-consuming, and dangerous, posing a significant risk to laboratory workers 1.
- Cultivation requires a BSL-3 laboratory because the bacteria are highly infective and can be hazardous for laboratory workers 1.
- A negative culture does not rule out a C. burnetii infection, especially in patients with chronic Q fever who have already received antibiotics 1.
Biosafety Protocols for Handling Coxiella burnetii
- Handling of specimens known or suspected to contain viable C. burnetii should be done in a BSL-3 facility and rendered nonviable or destroyed 1.
- Appropriate personal protective equipment (PPE) should be worn, including protective eyewear, disposable gloves, and shoe covers, and showering after working with C. burnetii under BSL-3 conditions is recommended 1.
- Unvaccinated workers should wear respiratory protection such as an N95 respirator when working with viable C. burnetii organisms in culture media or live animals 1.
Alternative Diagnostic Methods
- For clinical diagnosis, serological methods like immunofluorescence assay (IFA) or PCR are typically used instead of culture due to safety concerns and technical challenges 1.
- These alternative methods are preferred due to the significant infection risk to laboratory personnel associated with culturing Coxiella burnetii 1.
From the Research
Coxiella burnetii Culture Protocol
- The culture of Coxiella burnetii is mandatory to assess their susceptibility to antibiotics and sequence their genome in order to optimize patient management and epidemiological studies 2.
- Cultivating this fastidious microorganism is difficult and restricted to reference centers, as it requires biosafety level 3 laboratories and relies on cell culture performed by experienced technicians 2, 3.
- A novel high-content screening (HCS) isolation strategy based on optimized high-throughput cell culture and automated microscopic detection of infected cells with specifically designed algorithms targeting cytopathic effects has been developed 2.
- This method was more efficient than the shell vial assay, at the level of time dependency, when applied to both frozen specimens and fresh samples 2.
- The shell vial assay is also used for antibiotic susceptibility testing of C. burnetii isolates 4.
- Requirements for intracellular multiplication together with the necessity for biosafety level 3 facilities restrict the cultivation of C. burnetii to specialized laboratories 5.
- A novel medium formulation enabling axenic growth of C. burnetii has facilitated fundamental genetic studies 5.
Biosafety Considerations
- Coxiella burnetii is designated as a biosafety level 3 agent 6.
- Handling and analyzing ticks requires differentiation of C. burnetii from Coxiella-like organisms, which is an essential diagnostic prerequisite 5.
- Detection and quantification of the bacteria with conventional culturing methods is time-consuming and poses significant health risks 6.