The incidence of anaerobic bacteria in adult patients with chronic sinusitis: A prospective, single-centre microbiological study.

Introduction: Chronic sinusitis caused by anaerobes is a particular concern clinically, because many of the complications are associated with infections caused by these organisms. The aim of this study was to evaluate the incidence of anaerobic bacteria in chronic sinusitis in adults as a part of a prospective microbiological study.

Materials and methods: Over a one-year period, aspirations of maxillary sinus secretions and/or ethmoid cavities were derived in n = 79 adult patients with chronic sinusitis by endoscopy in a tertiary-care teaching hospital in Hungary. The qualitative and quantitative compositions of the total cultivable aerobic and anaerobic bacterial and fungal flora cultured on the samples were compared. Correct anaerobic species level identifications were carried out according to standard methods.

Results: Bacteria were recovered for all of the 79 aspirates and the numbers of the significant cultured isolates (with colony forming units ≥103) were between 1 and 10. A total of 206 isolates, 106 anaerobic and 100 aerobic or facultative-anaerobic strains were isolated. The most common aerobic bacteria were Streptococcus pneumoniae (n = 40), Haemophilus influenzae (n = 29), Moraxella catarrhalis (n = 6), Staphylococcus aureus (n = 7) and Streptococcus pyogenes (n = 6). The anaerobic bacteria included black-pigmented Prevotella spp. and Porphyromonas spp. (n = 27), Actinomyces spp. (n = 13), Gram-positive anaerobic cocci (n = 16), Fusobacterium spp. (n = 19) and Cutibacterium acnes (n = 8).

Conclusions: This study illustrates the microbial dynamics in which anaerobic and aerobic bacteria prevail and highlights the importance of obtaining cultures from patients with chronic sinusitis for guidance in selection of proper antimicrobial therapy.