Thursday, June 11, 2009

Methicillin-Resistant Staphylococcus aureus Furunculitis in the Outpatient Burn Setting

Methicillin-Resistant Staphylococcus aureus Furunculitis in the Outpatient Burn Setting

J Burn Care Res. 2009 Jun

Warner P, Neely A, Bailey JK, Yakuboff KP, Kagan RJ.
From the *Shriners Hospitals for Children, Cincinnati, Ohio; and daggerUniversity of Cincinnati, Cincinnati, Ohio.

Methicillin-resistant Staphylococcus aureus (MRSA) is becoming more predominant in the community. We have seen increasing cases of furunculitis in our outpatient burn clinic, which appear to develop weeks after the initial burn injury and in patients with limited inpatient stays. We performed a 3-year retrospective review of all outpatient burn patients who developed furunculitis. Data analyzed included length of hospital stay, type of injury sustained, culture and sensitivity results, and treatment provided. A total of 28 patients were identified with MRSA furunculitis, which presented as painful, hard, indurated boils with minimal purulent drainage. Adults had less extensive burn injuries (mean of 12% TBSA adults vs 20% TBSA children) with shorter hospital stays (mean 8 days adults vs 22 days children). Fifty-seven percent of the patients had multiple furuncules, involving both burned and nonburned areas. Patients with furunculitis had a less resistant MRSA strain than those without furunculitis. Of the 22 patients who received systemic antibiotic coverage, 14 (58%) were successfully treated with 1 antibiotic regimen, whereas 8 (33%) required multiple antibiotics. In this study, furunculitis in the outpatient setting was believed to be consistent with community-acquired MRSA. Incision and drainage was not sufficient in patients with multiple furuncles, and systemic antibiotics were administered. Through increased awareness of the prevalence of community-acquired MRSA in the community, appropriate antibiotic treatment can be initiated, and the discomfort and transmission risk associated with this disease can be minimized.

Lippincott, Williams & Wilkins

Monday, June 8, 2009

Topical Therapy for Methicillin-Resistant Staphylococcus aureus Colonization: Impact on Infection Risk.

Topical Therapy for Methicillin-Resistant Staphylococcus aureus Colonization: Impact on Infection Risk.

Infect Control Hosp Epidemiol. 2009 Jun

Robicsek A, Beaumont JL, Thomson Jr RB, Govindarajan G, Peterson LR.
From the Departments of Medicine (A.R.) and Pathology (R.B.T., L.R.P.), Feinberg School of Medicine, Northwestern University, Chicago, and the Department of Medicine (G.G.), the Division of Infectious Diseases (A.R.), the Division of Microbiology (R.B.T., L.R.P.), and the Center on Outcomes, Research, and Education (J.L.B.), NorthShore University HealthSystem, Evanston, Illinois.


We evaluated the usefulness of topical decolonization therapy for reducing the risk of methicillin-resistant Staphylococcus aureus (MRSA) infection among MRSA-colonized inpatients.


Retrospective cohort study. Setting and intervention. Three hospitals with universal surveillance for MRSA; at their physician's discretion, colonized patients could be treated with a 5-day course of nasal mupirocin calcium 2%, twice daily, plus chlorhexidine gluconate 4% every second day. Patients and methods. MRSA carriers were later retested for colonization (407 subjects; study 1) or followed up for development of MRSA infection (933 subjects; study 2). Multivariable methods were used to determine the impact of decolonization therapy on the risks of sustained colonization (in study 1) and MRSA infection (in study 2).


Independent risk factors for sustained colonization included residence in a long-term care facility (odds ratio [OR], 1.8 [95% confidence interval {CI}, 1.1-3.2]) and a pressure ulcer (OR, 2.3 [95% CI, 1.2-4.4]). Mupirocin at any dose decreased this risk, particularly during the 30-60-day period after therapy; mupirocin resistance increased this risk (OR, 4.1 [95% CI, 1.6-10.7]). Over a median follow-up duration of 269 days, 69 (7.4%) of 933 patients developed infection. Independent risk factors for infection were length of stay (hazard ratio [HR], 1.2 per 5 additional days [95% CI, 1.0-1.4]), chronic lung disease (HR, 1.7 [95% CI, 1.0-2.8]), and receipt of non-MRSA-active systemic antimicrobial agents (HR, 1.8 [95% CI, 1.1-3.1]). Receipt of mupirocin did not affect the risk of infection, although there was a trend toward delayed infection among patients receiving mupirocin (median time to infection, 50 vs 15.5 days; [Formula: see text]).


Mupirocin-based decolonization therapy temporarily reduced the risk of continued colonization but did not decrease the risk of subsequent infection.


Activity of the anti-MRSA carbapenem razupenem (PTZ601) against Enterobacteriaceae with defined resistance mechanisms.

Activity of the anti-MRSA carbapenem razupenem (PTZ601) against Enterobacteriaceae with defined resistance mechanisms.

J Antimicrob Chemother. 2009 Jun

Livermore DM, Mushtaq S, Warner M.
Antibiotic Resistance Monitoring & Reference Laboratory, Health Protection Agency Centre for Infections, 61 Colindale Avenue, London, NW9 5EQ, UK.


Razupenem (previously known as PTZ601, PZ-601, SMP-601 or SM-216601) is a novel carbapenem, active against Enterobacteriaceae as well as Gram-positive bacteria including methicillin-resistant staphylococci and enterococci.


We examined the effect of extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases on the activity of razupenem, using the CLSI agar dilution method to measure MICs for mutants, transconjugants and isolates with and without these enzymes.


ESBLs had no effect on the activity of razupenem against Escherichia coli and Klebsiella spp., and only a small effect when coupled with outer membrane impermeability. Inducible or, more especially, derepressed AmpC enzymes gave some protection, with most AmpC-derepressed Enterobacter and Citrobacter spp. requiring MICs of approximately 8 mg/L. This relative resistance was further increased when porins were lost, restricting drug uptake. Metallo- and class A-carbapenemases conferred resistance, with MICs >/=16 mg/L.


Razupenem has good activity against ESBL producers, but is affected by AmpC enzymes, especially when derepressed and coupled with outer membrane impermeability; its activity is also compromised by carbapenemases.