Are routine microbiological investigations indicated in the management of non-perianal cutaneous abscesses?

BACKGROUND: It is common practice to take a specimen of pus for microscopy and bacterial culture during drainage of abscesses. The aim of this study was to determine if routine culture and sensitivity had any therapeutic value in the care of patients with non-perianal cutaneous abscesses. PATIENTS AND METHODS: A retrospective analysis ofall patients undergoing drainage ofa cutaneous abscess during a two year period (June 2003 - June 2005) was performed. Patients were identified from the hospital database and theatre records, and those with perianal, pilonidal or surgical wound sepsis were excluded. Notes were reviewed for clinical details, culture results, subsequent admissions and attendance at follow-up. RESULTS: Of the 239 patients treated during this period, 74 patients had 77 operations to drain abscesses that matched the inclusion criteria. Specimens were sent from 52 (67.5%) procedures. Only 65.4% had an organism identified, of which methicillin-sensitive Staphylococcus aureus (MSSA) was the most commonly isolated organism (36.5%). Forty-one point six per cent of patients received antibiotics as part of their treatment. The results of the bacterial culture and antibiotic sensitivities were not known prior to discharge of any patient. CONCLUSION: This study shows that bacteriology swabs are frequently taken during incision and drainage of non-perianal cutaneous abscesses and had little impact on the subsequent treatment, though these results may not be applicable to immune-compromised patients.

Treatment of prosthetic valve infective endocarditis due to multi-resistant Gram-positive bacteria with linezolid.

OBJECTIVES: Clinical experience with linezolid in the treatment of infective endocarditis either alone or in combination with other agents is limited. We describe our experience in the treatment of two patients with IE due to multi-resistant Gram-positive bacteria. METHODS: One patient with MRSE and one with VRE endocarditis were treated with regimens containing linezolid. The killing kinetics of linezolid in combination with gentamicin or vancomycin against isolates of Staphylococcus epidermidis and Enterococcus faecalis were analysed in vitro. RESULTS: Clinical response and eradication of bacteraemia was achieved with linezolid therapy in both patients. Time-kill curve studies showed that linezolid was bacteriostatic against the MRSE and VRE isolates used. Combination with gentamicin or vancomycin did not produce synergy or antagonism but at best only marginal additive effect. CONCLUSIONS: Although bacteriostatic, linezolid provides an important therapeutic option in IE due to multi-resistant Gram-positive pathogens. It challenges the conventional wisdom that bactericidal synergy is required for the effective treatment of most cases of IE due to Gram-positive organisms.