Cuidados de enfermeria

AACN Advanced Critical Care Volume 22, Number 1, pp.5–12 © 2011, AACN

Drug Update

Earnest Alexander, PharmD, and Gregory M. Susla, PharmD Department Editors

Treatment of Methicillin-Resistant Staphylococcus aureus Surgical Site Infections
Elena M. Santayana, PharmD, BCPS Jacqueline Jourjy, PharmD, BCPS

is estimated that there are approximately 500 000 cases infecIttionsof patientswho undergo surgical procedures and is of surgical siteinseri(SSIs) each year in the United States. Surgical site infection occurs 2% to 5% associated with
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ous negative outcomes, including increased health care–associated morbidity and mortality.2 The risk of mortality increases 2- to 11-fold in patients with SSI.3 Moreover, the duration of postoperative hospitalization may increase by anaverage of 7 to 10 days because of an episode of SSI.1,4 Another important issue is the burden of increased costs for patients and health care institutions. The estimated cost per patient per SSI has ranged from $3000 to $29 000 in published studies.5 Accordingly, the appropriate and timely management of SSI is of critical importance to prevent serious complications. SSIs account for 20% of all skinand soft tissue infections present among patients who are admitted to hospitals.6 Among hospitals that report to the Centers for Disease Control and Prevention, Staphylococcus aureus is identified as the primary pathogen in 20% of SSI cases.7 Alarmingly, hospital data reported to the Centers for Disease Control and Prevention from 1992 to 2002 indicated that the rate of SSI caused by Staphylococcusaureus increased from 16.6% to 30.9%, whereas methicillin-resistant Staphylococcus aureus (MRSA) isolates increased from 9.2% to 49.3% during this time period.8 Resistance has become a major concern because SSIs caused by MRSA are typically more severe and have worse outcomes than those caused by methicillin-sensitive Staphylococcus aureus (MSSA).9 Other potential pathogens responsible for SSIsinclude Staphylococcus epidermidis (or coagulase-negative staphylococci), Enterococcus spp, Streptococcus spp, as well as gram-negative organisms, including Pseudomonas aeruginosa and Escherichia coli. Less commonly SSIs may be caused by fungi.7 Methicillin-Resistant Staphylococcus aureus Methicillin-resistant Staphylococcus aureus is a strain of Staphylococcus aureus that is resistant to -lactamantibiotics, including penicillins, cephalosporins, and carbapenems. The -lactams inhibit bacterial cell wall synthesis by binding to 1 or more of the penicillin-binding proteins (PBP) located on the bacterial cell.

Elena M. Santayana is Clinical Pharmacist Specialist, Critical Care, University of Chicago Medical Center, 5841 S Maryland Ave, MC 0010, Chicago, IL 60637(elena.santayana@uchospitals.edu). Jacqueline Jourjy is Assistant Professor of Pharmacy Practice, LECOM—Bradenton School of Pharmacy, Bradenton, Florida. DOI: 10.1097/NCI.0b013e3181ef86fe2049019

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Copyright © 2011 American Association of Critical-Care Nurses. Unauthorized reproduction of this article is prohibited.

Drug Update

A AC N

Staphylococcus aureus resistance to -lactam antibiotics is caused by thepresence of the mecA gene that codes for an altered PBP-2a. This alteration of PBP-2a prevents the antibiotic’s -lactam ring from binding to the bacterial cell. Consequently, the agent cannot exert its antimicrobial effect.10 Some risk factors associated with MRSA SSI include receipt of emergent or contaminated surgery, extended surgical duration, presence of comorbid conditions, and receipt ofimmunosuppressive therapy.11 In recent years, a distinct strain of MRSA has emerged. Because it affects individuals in the community who lack the traditional risk factors for drug-resistant infections, this strain has been termed community-associated MRSA (CA-MRSA). CA-MRSA has commonly affected children and young adults, men more than women, individuals of nonwhite race, and those sharing personal...