Release: Immediate Contact: Kenneth Satterfield561-447-5521 (May 9-14, 2002)703-519-1563[email protected]
Culture-Directed Therapy Recommended for Treatment of Chronic Sinusitis
When physicians prescribe medication based on experience, treatment may fail and antimicrobial resistance may result.
Boca Raton, FL -- Patients with chronic sinusitis, including those with previous sinus surgeries, often return to the physician with infections. The management of these patients routinely includes antibiotics. However, increasing levels of antibiotic resistance has caused many specialists to obtain cultures before prescribing medications.
Employing these cultures may increase the cost of therapy compared to making an "educated guess" as to which medications to use. On the other hand, treating without cultures may increase costs through the use of ineffective antibiotics.
To investigate whether empiric therapy is adequate treatment, researchers from Stanford Sinus Center reviewed the microorganisms identified in cultures from a cohort of chronic sinusitis patients with acute infections. The authors of "Is Empiric Therapy Sufficient for Acute Exacerbations of Chronic Sinusitis?" are Christopher A. Church MD, Winston C. Vaughan, MD, Susan M. Poutanen, MD MPH, Ellen Jo Baron PhD, all from the Stanford University School of Medicine, Stanford, CA. Their findings will be presented May 10, 2002, at the Annual Meeting of the American Rhinologic Society http://www.american-rhinologic.org/, at the Boca Raton Resort & Club, Boca Raton, FL.
Methodology: Patients reporting with an acute exacerbation of chronic sinusitis were routinely cultured over a 25-month period from July 1998 to July 2000. All cultures were obtained via endoscopic aspiration using nasal endoscopes.
A retrospective review of all corresponding sinus specimen culture orders and final reports was then completed.
Results: Approximately 1030 specimens from 470 patients were reviewed over the 25-month study period. The estimated average patient age was 44 years (range: 18-84 years), and approximately half of the patients were female. Approximately 70 percent of all patients had at least one positive sinus culture; the remaining 30% of patients failed to yield organisms from their cultures. An estimated 85 percent of all specimens processed for culture showed growth. A total of 2095 organisms were isolated from the estimated 1,030 specimens. Seventy-three percent were aerobic bacteria, and 27 percent were fungi.
Of all bacterial isolates, 67 percent were gram-positive and 33 percent were gram-negative. The most commonly isolated bacteria included coagulase-negative staphylococci (26 percent), Staphylococcus aureus (17 percent), Pseudomonas aeruginosa (nine percent), Streptococcus pneumoniae (six percent) and other alpha-hemolytic streptococci (nine percent).
Among gram-negative bacteria, the most frequent isolates included P. aeruginosa (26 percent), Hemophilus influenzae (10 percent), Stenotrophomonas maltophilia (nine percent), Moraxella catarrhalis (six percent) and Serratia marcescens (six percent). Thirteen percent of P. aeruginosa isolates were mucoid strains, despite the exclusion of specimens from cystic fibrosis patients.
Drug resistant isolates: Resistance to routinely prescribed antibiotics was often found among isolates thought to be pathogens. Thirty isolates of penicillin-resistant S. pneumoniae were identified, accounting for 35 percent of all S. pneumoniae isolates. In addition, 12 percent of all S. aureus isolates were methicillin-resistant, and 15 percent of all P. aeruginosa isolates were resistant to ciprofloxacin.
Fungal isolates: Approximately 35 percent of all fungal cultures exhibited growth. Fungal cultures most commonly yielded Aspergillus fumigatis group (29 percent), Aspergillus niger group (14 percent), and Alternaria species (eight percent). Among specimens processed for culture with positive fungal growth, pure fungal cultures were identified in 20 percent, representing nine percent of all positive specimens.
Conclusion: The microbiology data in this study reveals a high rate of isolation of gram-negative bacteria, drug-resistant bacteria, and fungi. Guessing which antibiotic to use would not be sufficient to effectively treat these patients. The frequency of negative cultures (30 percent) and cultures of non-pathogens (35 percent of bacterial isolates) suggests that empiric therapy may also result in the unnecessary use of antibiotics.
While culture directed approaches might be more expensive, they may ultimately result in more effective treatment and reduction in antimicrobial resistance. Further studies are being carried out.
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