Treatment for Skin Infection May be Effective Against Antibiotic-Resistant Chronic Rhinosinusitis

The treatment for chronic rhinosinusitis (CRS) includes the use of repeated doses of systemic antibiotics. Unfortunately, this treatment option may prove to be counter-productive. A recent survey by the Centers for Disease Control and Prevention (CDC) documented an increase in the use of broader-spectrum, more expensive antibiotics by office based physicians in the treatment of otitis media, rhinosinusitis, and other common infections. Their conclusion was that these "therapeutic misconducts" have led to the development of multi-resistant organisms, in which very few therapeutic options are now available.

With the emergence of antibiotic resistance, new therapeutic challenges have been encountered in this difficult patient population. One such challenge is the treatment of acute exacerbations of CRS caused by methicillin-resistant Staphylococcus aureus (MRSA), a common bacterial species found especially on skin (hair follicles). The treatment of these patients is controversial and often requires intravenous antibiotics. Furthermore, anecdotal experience suggests that intravenous antibiotics for the treatment of chronic rhinosinusitis due to MRSA provide at best transient benefits. No published studies have demonstrated the clinical efficacy offered by intravenous antibiotics for CRS due to MRSA.

A new study provides a retrospective review of using mupirocin nasal irrigations for MRSA exacerbations of CRS, either alone or in combination with either oral trimethoprim-sulfamethoxazole or oral doxycycline between January 2000 and October 2003. Mupirocin is an antibiotic often used to treat skin infections caused by Staphylococcus aureus.

The researchers believed that this novel treatment provides an alternative to intravenous antibiotics in the management of these complex patients. The authors of "Treatment of Chronic Rhinosinusitis Exacerbations due to Methicillin-Resistant Staphylococcus Aureus with Mupirocin Irrigations," are C. Arturo Solares MD, Pete S. Batra MD, Geraldine S. Hall PhD, and Martin J. Citardi MD, all with The Cleveland Clinic Foundation. This paper will be presented at the spring meeting of the American Rhinologic Society being held April 30 through May 1, 2004 in Phoenix.

The authors caution that despite the encouraging results, this study has several limitations. The retrospective methodology precludes patients' outcomes from be assessed relative to a control group that received only saline irrigations. Therefore, it is possible that the patients improved solely as a result of the mechanical debridement provided by the saline irrigation. In addition, comparison to treatment with intravenous antibiotics is not feasible.

The role of MRSA in CRS pathophysiology is controversial. The findings do not totally clarify the question of whether MRSA is an etiologic agent in this patient population or is it simply a colonizer. Clinical observations suggest that MRSA has a role in acute exacerbations of CRS and the use of antibiotic treatment leads to the improvement of symptoms in a significant percentage of patients.

This study does provide a novel treatment strategy for the treatment of CRS exacerbations due to MRSA. Mupirocin nasal irrigations, usually administered in combination with oral doxycycline or trimethoprim/sulfamethoxazole, improved patient symptoms and at least reduced MRSA recovery on subsequent endoscopic culture. This therapeutic strategy may serve as an alternative to intravenous antibiotics in this recalcitrant disease process. Although the risk of recurrent MRSA exacerbation remains, the morbidity associated with this therapy is minimal. Thus, mupirocin nasal irrigations may provide a relatively simple means for the long-term management of MRSA exacerbations of CRS.

Methodology: The results of endoscopic sinus cultures for CRS exacerbations performed in the Cleveland Clinic between January 2000 and October 2003 were reviewed. Patients with MRSA positive sinus cultures obtained under endoscopic visualization in the outpatient rhinology clinic were identified. The charts of patients who received mupirocin nasal irrigations (22 g, two percent ointment in one liter of normal saline; irrigate each side with 50 cc bid for four to six weeks) for MRSA exacerbations of CRS, either alone or in combination with either trimethoprim-sulfamethoxazole DS (one tablet po bid, 4 weeks) or doxycycline (100 mg po bid, four weeks), were reviewed further. The charts were analyzed for the following information: age, sex, previous sinus surgeries, related illnesses, status at the end of treatment including culture results if available, and length of follow-up. The outcome after each episode in three categories (ie. symptoms, endoscopy and bacteriology) was rated as improved, same or worse.

Results: Forty-two MRSA positive cultures were obtained from 24 patients (mean age: 61 years; range: 38 to 82 years; 15 women and nine men). Twenty-two patients had at least one endoscopic surgical procedure. Fourteen patients had documented inhalant allergies, 13 patients had asthma and eight patients had sinonasal polyposis. Other less common illnesses found in the patients included rheumatoid arthritis (two patients), COPD (two patients), and one patient each were diagnosed with gastroesophageal reflux, bronchiectasis, systemic lupus erythematosus, and frontal bone fibrous dysplasia.

Twenty-eight episodes were treated with mupirocin nasal irrigations and doxycycline; four were treated with mupirocin nasal irrigations and trimethoprim-sulfamethoxazole DS, and seven episodes were treated with mupirocin nasal irrigations alone. Patients were re-evaluated at approximately four to six weeks. Repeat cultures were not obtained in 12 patients (due to clinical and endoscopic resolution). Adequate follow-up was unavailable for three patients and of the 27 repeat cultures only one grew MRSA. Twelve patients had at least one recurrence, with a mean number of episodes of 1.75 (range, one to eight episodes). The mean follow-up was 11.8 months (range, three to 27 months).

Conclusions: This data suggests that in some cases, mupiromicin nasal irrigations are a viable alternative to intravenous antibiotics in the treatment of acute exacerbations of CRS due to MRSA. In 42 instances of MRSA-positive sinus cultures, only 14 patients were persistently symptomatic after treatment, and in these 14 patients, endoscopic cultures performed at the end of treatment revealed MRSA in only one patient. Admittedly, the risk of recurrent MRSA exacerbations remains despite this treatment, but this risk is not eliminated by the use of intravenous antibiotics which entail greater costs and morbidity.

Source: American Rhinologic Society

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