No abstract

Thirty patients were treated for colonization or for skin and soft tissue infections caused by methicilinresistant Staphylococcus aureus. Three treatment regimens were evaluated, each progressively more aggressive. One regimen was 750 mg of ciprofloxacin twice daily for 5 days, the second regimen was 750 mg of ciprofloxacin twice daily for 10 to 14 days, and the final regimen was 750 mg of ciprofloxacin twice daily plus 300 mg of rifampin twice daily for 21 days. It appears that ciprofloxacin alone produced an initial eradication rate in at least one site in 50% of the patients, regardless of whether the treatment was for 5 or up to 14 days. All of the patients with eradication became recolonized within 1 week posttherapy. When rifampin was combined with ciprofloxacin, the eradication rate was 100% when the isolates were susceptible to both agents, and these patients remained free of methicillin-resistant S. aureus at 1-week and 1-month follow-ups.Methicillin-resistant Staphylococcus aureus (MRSA) has recently emerged as both a colonizing organism and a pathogen among many hospitalized patients. The therapy of infections caused by this organism or the eradication of colonization is particularly difficult. None of the beta-lactam antibiotics appears to be clinically effective; chloramphenicol has not proven effective for the treatment of staphylococcal infection in the past; erythromycin therapy produced rapid emergence of resistance and treatment failures; and finally, the use of aminoglycosides has resulted in the rapid emergence of resistant small-colony variants. Bacitracin, although active against this organism, cannot be applied to the upper nares comfortably to enable eradication of the carrier state. Although vancomcyin has proven effective for treating staphylococcal infections in many body sites, this therapy is expensive. Furthermore, vancomcyin is ineffective for those body sites in which vancomycin does not penetrate well, such as the nares.With the availability of the newer quinolone compounds, many of which show adequate to good in vitro activity against both methicillin-susceptible and methicillin-resistant staphylococci (9, 10), enthusiasm for use of the quinolones for treatment of infection or colonization by MRSA seems justified. We therefore evaluated the effectiveness of ciprofloxacin for treatment of skin and soft tissue infections and for eradication of MRSA carriage. MATERIALS AND METHODSPatient population. Patients identified by the primary care physicians or infection control staff as infected or colonized with MRSA as the primary or sole pathogen were evaluated for entrance into the study. All patients were interviewed and clinically reevaluated by the principal investigator (R.H.K.E.) and informed consent was obtained prior to enrollment. Cultures of the skin structures were obtained by aspiration from the leading edge of the infection. Cultures of groin and perirectal areas were obtained by using salinesoaked cotton-tipped swabs over an area of at least 10 cm2. Cultures of the nares w...

During the first twelve months after ciprofloxacin was introduced for clinical use at our institution, 65 new patients were found to be either infected or colonized by methicillin-resistant Staphylococcus aureus (MRSA) which were also ciprofloxacin resistant (CR-MRSA). Only 18 of these patients (28%) had been previously exposed to this antibiotic. Nine (50%) of the 18 patients had received ciprofloxacin for treatment for a pathogen other than MRSA. Although the initial cases of colonization or infection with CR-MRSA can be directly related to ciprofloxacin use, many of the subsequent cases of colonization and infection were not the consequence of ciprofloxacin therapy but rather hospital transmission of existing CR-MRSA.

In the past, vancomycin has been reported to cause renal failure during intravenous administration; however, more recently, such renal toxicity is alleged not to occur because of increased purity of the vancomycin preparations. In this study, 23 patients were prospectively examined during intravenous vancomycin administration for changes in renal function. Vancomycin was administered for an average of 15 days. The blood urea nitrogen (BUN) changes averaged + 1.7 mg/dl and the creatinine changes averaged + 0.06 mg/dl. Since the accuracy of the serum creatinine determination was ± 0.3 mg/dl, clinically significant deterioration of renal function occurred in 4 patients or 17%. Even among these 4 patients with documented worsening of renal function, we suspect that deterioration was related to the infection being treated. With close monitoring of dosing, the propensity of vancomycin to cause nephrotoxicity may be less than once thought.

Effective antimicrobial therapy for infection or colonization by methicillin-resistant Staphylococcus aureus (MRSA) is very limited. In some institutions, the majority of strains remain susceptible to clindamycin in vitro. We report five patients with colonization or infection of varying severity caused by MRSA who had the organism successfully eradicated by clindamycin. In one patient who had an MRSA infection that persisted during vancomycin therapy clindamycin therapy was able to finally eradicate the organism. Clindamycin should be seriously considered as alternative therapy for colonization or infection by MRSA.