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Surgical Aspects of MRSA Lena Napolitano, MD, FACS, FCCP, FCCM Discussion Dr Kollef: I think I have heard people say that for some of these so-called spider bites, if you drain them you may not even need antibiotics. This is probably not correct. Dr Napolitano: Pediatric studies have reported that if the abscess is less than 5 cm in diameter, you could get away without using antibiotics.1 Not 100% of the time, but a good percentage of the time. The question is how to determine which ones need the antibiotics. A recent randomized trial of cephalexin versus placebo in patients with uncomplicated skin abscesses (mostly due to methicillin-resistant Staphylococcus aureus [MRSA]) documented a 90.5% cure rate in the placebo arm.2 These data provide evidence that antibiotics may not be necessary after surgical drainage of uncomplicated abscesses. But when lesions are large, are surrounded by cellulitis, or do not have drainable foci, or when patients manifest systemic signs of infection, antimicrobial therapy is warranted.3 Dr Bartlett: There is some question right now regarding the policy of the Veteran’s Affairs required by some state legislatures that all admissions must be screened for MRSA in the nose. If it is positive they do not say what you need to do but the assumption is that you give the patient mupirocin and chlorhexidine. There were 2 back-to-back papers that examined this. One from Sweden showed no impact of screening, isolation, and treatment for MRSA.4 In fact, it turned out to be a risk with an odds ratio of 1.2, so a 20% increase. So the screening didn’t help. Then there was a series from Chicago that did the sequential analysis before and after MRSA screening and infection control precautions.5 With universal screening and infection control and so forth they had a 76% reduction in MRSA infections. Dr Napolitano: The STAR ICU (Strategies to Reduce Transmission of Antimicrobial Resistant Bacteria in Adult Intensive Care Units) trial was a National Institutes of Health-sponsored study by the Bacteriology and Mycology Study Group that prospectively randomized ICUs to intensive versus standard infection control.6 The objective of this study was to evaluate the effectiveness of an intensive infection control strategy that included the use of: (1) surveillance cultures to identify patients with colonized with MRSA or vancomycin-resistant enterococci (VRE); (2) preemptive universal gloving for newly admitted patients while awaiting admission surveillance culture results; and (3) contact precautions in the care of these patients for reducing the transmission of MRSA and VRE in adult ICUs. No difference in the incidence density of new colonization or infection events or for MRSA or VRE was noted between the 2 groups. These data were presented at SCCM (Society for Critical Care Medicine) and SHEA (Society for Healthcare Epidemiology of America) in 2007. One problem with this study is the way that intensive infection control was done. Surveillance was done by nasal swab for MRSA, and rectal swab for VRE. But the intensive infection control was gloves only until they were identified as being colonized or not colonized. Maybe it should have been gloves, gowns, and masks for the intensive infection control group. Compliance may have been much worse if that were the experimental design though. Dr Bartlett: There were 2 other things that have been criticized in these studies. One is that looking for MRSA in the nose is probably not adequate. Dr Napolitano: Particularly in our surgical patients. You have got to swab the open wounds in order to obtain an accurate determination of MRSA colonization. Dr Bartlett: The other problem was that they put all of the healthcare workers on infection control precautions, but they did not monitor compliance. Nobody knows whether compliance was good or bad. Dr Napolitano: Every unit had compliance monitored regarding hand washing. And they found the same thing that is found in every study with hand washing, which is that compliance was approximately 60%. So you do not have a true, intensive infection control group, even in this large, prospective, randomized trial. References 1. Lee MC, Rios AM, Aten MF, et al. Management and outcome of children with skin and soft tissue abscesses caused by community-acquired methicillin-resistant Staphylococcus aureus. Pediatr Infect Dis J. 2004;23:123-127. 2. Rajendran PM, Young D, Maurer T, et al. Randomized, double-blind, placebo-controlled trial of cephalexin for treatment of uncomplicated skin abscesses in a population at risk for community-acquired methicillin-resistant Staphylococcus aureus infection. Antimicrob Agents Chemother. 2007;51:4044-4048. 3. Napolitano LM. Early appropriate parenteral antimicrobial treatment of complicated skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus. Surg Infect. 2008;9(suppl 1):s17-s27. 4. Jarvis WR, Muto C. Universal screening for methicillin-resistant Staphylococcus aureus by hospitals. JAMA. 2008;300:504. 5. Robicsek A, Beaumont JL, Paule SM, et al. Universal surveillance for methicillin-resistant Staphylococcus aureus in 3 affiliated hospitals. Ann Intern Med. 2008;148:409-418. 6. Huskins WC, O’Grady NP, Samore M, et al. Design and methodology of the Strategies to Reduce Transmission of Antimicrobial Resistant Bacteria in Intensive Care Units (STAR-ICU) trial. Infect Control Hosp Epidemiol. 2007;28:245-246.
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