The Health Care Worker, Resistant Bacteria (MRSA), and Preventing Contagion
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Methicillin-resistant S. aureus infection is a particularly serious problem in hospitals, where MRSA often exceeds 25% of S. aureus isolates. Because MRSA strains are not susceptible to cephalosporin or semi-synthetic penicillin antibiotics, intravenous vancomycin is usually employed when MRSA infections occur. For reasons of cost, toxicity, and to avoid driving the emergence of vancomycin-resistant Enterococcus (VRE) or the more fearsome vancomycin-resistant S. aureus (VRSA), vancomycin is not routinely ordered at the outset of most infections. Rather, empiric antibiotics are selected that would usually treat the affected body system. A delay of 36-48 hours may occur before culture results identify MRSA and antibiotics are changed. Like all bacterial species, there are many strains of MRSA. Some posit that MRSA may be inherently more pathogenic than methicillin-sensitive S. aureus (MSSA), but the data are inconclusive.1 Also of note, some MRSA strains are susceptible to antibiotics other than vancomycin, and some of these can be given orally. Community-acquired MRSA strains may be more broadly susceptible, as shown in a recent study comparing community-acquired to hospital-acquired MRSA: ciprofloxacin 79% versus 16% susceptible; clindamycin 83% versus 21%; erythromycin 44% versus 9%; trimethoprim-sulfamethoxazole 95% versus 90%; and vancomycin, both 100%.2
To prevent the spread of MRSA between hospitalized patients, hospital epidemiologists recommend contact precautions for infected or colonized patients. Because MRSA colonization often persists for months or years, at our institution a “flag” is maintained in the patient’s record and precautions are immediately resumed if the patient returns to the hospital at a later time.
Presence of MRSA may delay or alter discharge plans. Many nursing homes also employ contact precautions for patients known to have recently carried MRSA. Patients with MRSA can be placed in rooms with other MRSA-positive patients (cohorting) or in private rooms, but staff members must still observe contact precautions such as using gloves for all contact and disposable gowns for more extensive care, adding cost and reducing efficiency. Consequently, finding post-hospital institutional placement for patients with MRSA may be difficult. The problem is compounded by a misunderstanding of “mersa” by staff members, patients, and family members. Methicillin-resistant S. aureus is perceived by some to be a mysterious and dangerous contagion rather than a variant strain of a bacterium that is commonly present on many individuals’ skin or inside their nares.
Given the prevalence and persistence of MRSA, presence of this bacterium poses a question for medical practitioners who work in outpatient environments such as the office or the home: should we follow contact precautions in these other settings? Often, MRSA-carrying patients appear in our offices or are seen on house calls within days or weeks of being discharged from hospitals, where we carefully donned gloves, used “dedicated” stethoscopes that stayed in the patients’ rooms, washed hands between patients with antiseptic soap, and avoided surface contact that could transfer microorganisms. Sitting on the bed of a patient with MRSA in a wound or VRE in his or her stool would not be compliant with contact precautions. Could we not see ourselves unwittingly sitting on the bed of such a patient in the home? The only real difference lies in the distance we travel between patients.
Intuitively, it seems unlikely that MRSA infection is being spread in an epidemic manner from one home care patient to the next by careless health care providers; cause-and-effect cases are difficult to recall. Yet, home health care workers usually have no way of knowing when acute illnesses that may have resulted from nosocomial contagion occur in their patients.
References
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