Microbiology of Intracranial Abscesses and Their Associated Sinusitis

Abstract

To evaluate the organisms recovered from infected sinuses and associated intracranial abscesses (IAs). Design: Retrospective review of findings from aspirate of pus from 10 infected sinuses and their corresponding IAs. Setting: Academic medical center. Patients: Ten patients diagnosed as having sinusitis (age range, 7-58 years). Main Outcome Measure: Aerobic and anaerobic bacteria findings from infected sinuses and IAs. Results: Polymicrobial flora was found in 9 sinuses and 8 IAs. Anaerobes were isolated from all sinuses and 9 IAs. A total of 26 isolates (2.6 isolates per specimen) were recovered from the sinuses: 19 anaerobic, 6 aerobic or facultative, and 1 microaerophilic; 17 isolates were found in the IAs (1.7 isolates per site): 13 anaerobic, 2 aerobic or facultative, and 2 microaerophilic. The predominant anaerobes were Fusobacterium species (in 5 corresponding sinuses and abscesses, 1 in a sinus only, and 1 in an IA only), Prevotella species (in 3 corresponding sinuses and abscesses), Peptostreptococcus species (in 2 corresponding sinuses and abscesses, and 4 in a sinus only), Staphylococcus aureus, Haemophilus influenzae type b, microaerophilic streptococci, and Bacteroides ureolyticus (in 1 corresponding sinus and abscess each). Streptococcus pneumoniae was recovered 2 times, only from a sinus. ␣-Hemolytic streptococci and ␤-hemolytic streptococci group F were each isolated once from the sinus. Concordance in the microbiological findings between the sinus and the IA was found in all instances. However, certain organisms were present at only one or the other site. Conclusion: These data illustrate the concordance in the recovery of organisms from infected sinuses and their associated IA and confirm the importance of anaerobic bacteria in sinusitis and IA.

Microbiology of acute complicated bacterial sinusitis at the University of the Witwatersrand

“…Negative culture rates are a measure of prior antibiotic consumption, specimen handling and laboratory standards, and may vary widely from 0% to above 50%. 6,12 In this study, the negative culture rate of 27.9% is comparable to that encountered in similar studies. 2,4,11 Recent publications mention S. milleri as being the most common pathogen in patients with complicated sinusitis.…”

“…Reports from several smaller studies quote higher isolation rates, ranging from 7.7% to 11.9%. 1,2,4,6,8,12 On the other hand, total absence of S. pneumoniae is also reported. 7 Studies have shown M. catarrhalis to be a frequent isolate in cultures from patients with acute sinusitis.…”

“…In medical literature the aerobic species cited as being among the most prevalent include S. aureus, 3,6,7,[11][12][13] H. influenzae, 1,2,6,9 S. milleri, 4,5 S. pneumoniae, 2,9,12 S. viridans 3,6 and M. catarrhalis. 2,9 The most frequently reported anaerobes include Peptostreptococcus, Prevotella, Fusobacterium, Propionibacterium and Bacteroides.…”

“…The notable absence of S. milleri as seen at JH is also reported by other authors. 3,6,7,[11][12][13] Lancefield group A, C, F and G β-haemolytic streptococci (10.8%) were isolated at both hospitals. Group C, with 11 isolates, had the highest count, followed by groups A and F, then finally by group G ( Table I).…”

“…Previous studies cite wide variations, of between 2.8% and 26%, in the incidence of positive isolates of H. influenzae in complicated sinusitis. 1,2,[4][5][6]12 Equivalent studies attach no importance to H. influenzae as a pathogen. 3,8,11,13 Coagulase-negative staphylococci have long been regarded as non-pathogenic, but in a recent study their role as important pathogens is recognised.…”