Health-care-acquired infections (HAI), previously referred to as nosocomial infection, caused by antibiotic-resistant pathogens is an ongoing topic of debate in the health care industry. Patients with wounds may be at a higher risk for contracting these pathogens.
The Centers for Disease Control and Prevention (CDC) has estimated that approximately 13,300 Americans died in 1992 of health-care-associated infections caused by antibiotic-resistant pathogens. Using that figure, it can be estimated that 130,000 to 150,000 patients have died of these infections in US hospitals during the past decade. 1
Methicillin-resistant Staphylococcus aureus (MRSA) was first recognized in Europe and the United States in the late 1960s, 2,3 and is now evidenced worldwide. In fact, MRSA accounts for a growing proportion of S aureus isolated from hospitalized patients in many countries. According to 2003 National Nosocomial Infections Surveillance reports, the proportion of intensive care unit patients with S aureus nosocomial infections resistant to oxacillin has increased from 30% in 1989 to 60% in 2003. 4
Once considered only a nosocomial pathogen, MRSA appeared in nonhospitalized patients in 1980, primarily among intravenous drug users. 5,6
Debate over the prevalence of MRSA in the community setting continues today. Some studies illustrate the spread of MRSA within community settings, but others report that MRSA transmission occurs only in health care institutions. 7-14 In 2003, Jernegan et al 15 conducted a prevalence study of MRSA colonization among patients presenting to a university hospital by performing surveillance cultures at the time of hospital admission. Of the 974 patients cultured, 21% had S aureus isolated, and 26 (2.7%) had MRSA, representing 12.7% of all patients colonized with S aureus.15 The independent predictors of MRSA colonization in the study's population were admission to a nursing home in the previous year or a hospitalization of 5 days or longer during the preceding year.
These findings are contrary to those of other investigators reporting on the emerging of MRSA as a community pathogen. These studies, however, are retrospectively dependent on microbiology reports and use criteria of culture positive less than 48 hours after admission. 7-10 Because MRSA can persist for months or years, it is difficult to distinguish between true community-acquired and health care-acquired colonization. 16
Two other prospective studies, supporting the finding that MRSA isolated from patients on admission to a hospital correlated with a previous health care system admission, suggest that community-acquired MRSA is uncommon. 17,18 It may be possible that community-acquired MRSA is dependent on a geographic factor or specific high-risk population, such as, children in day care, inmates, sport teams, Native Americans, and other minorities. 19,20,21
In addition, acute rehabilitation units are considered high-risk populations for MRSA colonization/infection because the majority of those patients are transferred from an acute care hospital or nursing home. 22
Manian et al 23 looked at routine screening for MRSA on admission to acute rehabilitation units and reported a 12% isolation rate for MRSA on newly admitted patients and 7% for in-house transfers.
Of note to wound care practitioners, the first 2 cases of VRSA in the United States involved patients with chronic lower extremity ulcers.
History of MRSA infection/colonization and transfer from outside sources were independently associated with positive MRSA screening cultures. However, this represented only 37% of the patients admitted with MRSA colonization, suggesting the value of screening cultures for all admissions.
A new resistant organism emerges
These studies indicate that identifying MRSA-colonized patients is necessary if we are to understand the epidemiology of this organism and apply it to the newest resistant organism, vancomycin-resistant Staphylococcus aureus (VRSA). In addition, patients with colonized MRSA during their hospitalization need postdischarge follow-up. A recent report showed that approximately 50% of MRSA infections in patients who were initially identified to be colonized in a health care setting occurred after discharge. 24 These infections were often severe and involved soft tissue, pneumonia, and osteomyelitis.
VRSA is also emerging in the health care setting. The CDC reported 8 confirmed cases in the United States, and reported cases in France, Hong Kong, Scotland, Japan, and Korea. Current evidence indicates 2 risk factors for infection with VRSA: the use of vancomycin in the prior month and previous MRSA-positive culture. 25
The first 2 cases of VRSA (1 in Michigan, 1 in Pennsylvania) occurred in the summer of 2002 and in the outpatient setting. Both patients had lower extremity ulcers. Table 1 illustrates the characteristics of each case and exposure facts.
Based on available data, 3 facts that are known about these resistant bacteria:
* prevalence in the health care setting is increasing
* transmission occurs outside of the health care setting
* VRSA is emerging.
How do these trends affect the wound care patient and health care provider? And, what can be done to control the spread of MRSA/VRSA?
If not hospitalized, patients with acute or chronic wounds are usually treated in long-term-care facilities, wound clinics, rehabilitation units, or the home. These settings have been shown to significantly affect colonization or infection with MRSA/VRSA. Although wound culturing has not been shown to provide clinically relevant information, surveillance cultures for MRSA/VRSA may be indicated in this patient population. In fact, this may affect the prevalence of MRSA. Many hospitals have been reluctant to conduct surveillance cultures, but several studies have shown that screening high-risk patients and having established infection control policies can provide control of MRSA. 24,25
Patients with wounds, especially chronic lower extremity wounds, can be considered high risk because of an underlying condition, frequent access to health care, or residency in long-term-care settings. All these factors are considered to predispose the patient to MRSA/VRSA.
Making an Impact on MRSA/VRSA
Wound care providers can make the same impact on MRSA as did the Rhode Island infection control practitioners in 2002 when they decided that the increasing MRSA prevalence needed a collaborative, statewide solution. The guidelines they developed and distributed have made them leaders in MRSA control measures. Wound care professionals could take the same stand.
The gap between evidence and practice is a consistent finding in research of health service. 26 In a recent article on best evidence to best practice, Grovi et al 27 state, "Even if doctors are aware of the evidence and are willing to change, to alter pattern of care is difficult[horizontal ellipsis]." The researchers identify the following steps in trying to change or implement a new practice:
* involve relevant people
* develop a proposal
* study the main difficulties in achieving change
* select a set of strategies/measures
* develop a budget.
Wound care professionals can make an impact on MRSA/VRSA in their specialized population. Accept the challenge and make it a priority in 2004.
Acknowledgment:
The author wishes to acknowledge the help of Arlene Shubin in the preparation of this manuscript.
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