Introduction: Aspiration pneumonia is increasingly recognised as a common condition. Studies in the 1970s recommended anaerobic coverage, but recent studies and the ATS/IDSA guidelines suggest it may not necessarily benefit prognosis. However, no systematic review has been done on this topic, and guidelines have mainly referenced observational studies. Clinical practice should be based on current data reflecting the shift in causative bacteria. The aim of this review was to investigate whether anaerobic coverage is recommended in the treatment of aspiration pneumonia.

Methods: A systematic review and meta-analysis of studies comparing antibiotics with and without anaerobic coverage in the treatment of aspiration pneumonia was performed. The main outcome studied was mortality. Additional outcomes were resolution of pneumonia, development of resistant bacteria, length of stay, recurrence, and adverse effects. PRISMA guidelines were followed.

Results: From an initial 2523 publications, one RCT and two observational studies were selected. The studies did not show a clear benefit of anaerobic coverage. All included studies reported no benefit of anaerobic coverage in improving mortality. Studies reporting resolution of pneumonia, length of hospital stay, recurrence of pneumonia, and adverse effects showed no benefit of anaerobic coverage. The development of resistant bacteria was not discussed in these studies.

Conclusion: In the current limited literature, there is no clear evidence to recommend routine anaerobic coverage in the treatment of aspiration pneumonia. Guidance is needed to help clinicians determine which cases require anaerobic coverage.