Association between obligatory anaerobes and empyema caused by Streptococcus anginosus group bacteria

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Pulmonology

Background:

• Empyema frequently involves co-infections with Streptococcus anginosus group (SAG) bacteria and obligate anaerobes.
• The epidemiology and pathological impact of these co-infections remain poorly understood.

Purpose of the Study:

• To investigate the prevalence of obligate anaerobes in SAG-mediated empyema.
• To compare the diagnostic yield of molecular methods versus conventional cultures for detecting anaerobes.
• To explore potential differences in clinical and radiological features associated with SAG-mediated empyema with or without anaerobic co-infection.

Main Methods:

• Retrospective analysis of 44 patients with pleural effusion microbiota evaluation (January 2006 - March 2018).
• Detection of SAG bacteria using culture analysis of pleural effusion.
• Identification of obligate anaerobe phylotypes using the clone library method and anaerobic culture.

Main Results:

• Twelve patients were diagnosed with SAG-mediated empyema via culture.
• The clone library method detected anaerobes in 66.7% of cases, significantly higher than the 16.7% detected by anaerobic culture.
• No significant clinical differences were found between SAG-mediated empyema with and without anaerobes, except for chest CT findings.

Conclusions:

• Conventional culture methods may underestimate the prevalence of anaerobic co-infections in SAG-mediated empyema.
• Molecular techniques like the clone library method offer superior detection of anaerobic bacteria in this context.
• Radiological features may differ between SAG-mediated empyema with and without anaerobic co-infection, warranting further investigation.