No clear benefit of anaerobic coverage for treating aspiration pneumonia

"In the current review, the data is not adequate to assess the necessity of covering anaerobic bacteria with antibiotics as an initial treatment of aspiration pneumonia," the investigators wrote. "Further research is required to determine which cases need antibiotic coverage if any."

Aspiration pneumonia has become a leading cause of death and hospitalization in adults. It carries a significant socioeconomic burden worldwide, contributing to up to 90% of pneumonia in the elderly. Aspiration pneumonia is a subtype of hospital-acquired and community-acquired pneumonia with a poor diagnosis. Therefore, it is essential to investigate the current optimal management of aspiration pneumonia.

Anaerobic bacteria have been suggested to play a critical role in the pathogenesis of aspiration pneumonia. Due to these findings, it has become a common practice to consider routine anaerobic coverage in individuals suspected of having aspiration pneumonia. However, recent studies have suggested that anaerobic coverage may not necessarily improve clinical outcomes or be harmful.

Considering that clinical data should be based on current data implying the shift in causative bacteria, Yuki Yoshimatsu, Lewisham and Greenwich NHS Trust, London, UK, and colleagues investigated whether anaerobic coverage is recommended in the treatment of aspiration pneumonia.

For this purpose, the researchers conducted a meta-analysis and systematic review comparing studies with and without anaerobic coverage for treating aspiration pneumonia. Only one randomized trial and two observational studies were eligible for the review.

The study's primary outcome was mortality. Additional outcomes included the development of resistant bacteria, resolution of pneumonia, recurrence, length of stay, and adverse effects.

The researchers reported the following findings:

• From an initial 2523 publications, one randomized control trial and two observational studies were selected.
• The studies did not show a clear benefit of anaerobic coverage.
• Upon meta-analysis, anaerobic coverage did not improve mortality (Odds ratio 1.23).
• Studies reporting the resolution of pneumonia, length of hospital stay, recurrence of pneumonia, and adverse effects showed no benefit of anaerobic coverage.
• The development of resistant bacteria should have been discussed in these studies.

"Although very limited in number, the publications showed no clear evidence to recommend anaerobic coverage in the treatment of patients diagnosed with aspiration pneumonia," the researchers wrote. "No included studies reported the benefit of anaerobic coverage in improving mortality."

"Data is insufficient to assess the necessity of anaerobic coverage," they concluded.

Reference:

Yoshimatsu, Y.; Aga, M.; Komiya, K.; Haranaga, S.; Numata, Y.; Miki, M.; Higa, F.; Senda, K.; Teramoto, S. The Clinical Significance of Anaerobic Coverage in the Antibiotic Treatment of Aspiration Pneumonia: A Systematic Review and Meta-Analysis. J. Clin. Med. 2023, 12, 1992. https://doi.org/10.3390/jcm12051992