Post-Discharge Methicillin-Resistant Staphylococcus aureus Infections: Epidemiology and Potential Approaches to Control
Wound Care
The presence of a chronic wound in the post-discharge period is associated with a 4.41-fold increased risk of invasive MRSA infection [25]. Although randomized controlled trials are lacking, it is prudent to ensure that wounds are fully debrided to remove devitalized tissue that can be fertile ground for a MRSA infection. The burden of organisms on a chronic wound is often very large, creating high risk of resistance when exposed to antimicrobial agents. Decolonization therapy is not likely to meet with durable success in such cases and should probably be avoided, except in special circumstances, eg, in preparation for cardiothoracic surgery.
Infection Control in Nursing Home Settings
In the Active Bacterial Core cohort, discharge to a nursing home was associated with a 2.1- to 2.65-fold increased risk of invasive MRSA infection [24,25]. It is notable that the authors controlled for the Charlson comorbidity index, suggesting that nursing home care is more than a marker for comorbidity [25]. The tension between the demands of careful infection control and the home-like setting that is desirable for long-term care creates challenges in the prevention of invasive MRSA infection. Nevertheless, careful management of invasive devices and wounds and antimicrobial stewardship are strategies that may reduce the risk of invasive MRSA infection in long-term care settings. Contact precautions for colonized nursing home residents are recommended only during an outbreak [46]. Staff should be trained in proper application of standard precautions, including use of gowns and gloves when handling body fluids. A study of an aggressive program of screening, decolonization with nasal mupirocin and chlorhexidine bathing, enhanced hand hygiene and environmental cleaning demonstrated a significant reduction in MRSA colonization [47]. An increase in mupirocin resistance during the study led to a switch to retapamulin for nasal application. The Association of Practitioners of Infection Control has issued guidance for MRSA prevention in long-term care facilities [48]. The guidance focuses on surveillance for MRSA infection, performing a MRSA risk assessment, hand hygiene, and environmental cleaning.
Antimicrobial Stewardship
Antimicrobial therapy, especially with fluoroquinolones and third- or fourth-generation cephalosporins, is associated with increased risk of MRSA colonization and infection [43,49,50]. Implementation of an antimicrobial stewardship program, coupled with infection control measures, in a region of Scotland resulted in decreased incidence of MRSA infections among hospital inpatients and in the surrounding community [51]. Thus a robust antimicrobial stewardship program is likely to reduce post-discharge MRSA infections.
Role of Hand Hygiene
The importance of hand hygiene in the prevention of infection has been observed for nearly 2 centuries [52]. Multiple quasi-experimental studies have demonstrated a decreased infection rate when hand hygiene practices for health care workers were introduced or strengthened. A randomized trial in a newborn nursery documented a decrease in transmission of S. aureus when nurses washed their hands after handling a colonized infant [53]. In addition to health care providers, patient hand hygiene can reduce health care–associated infections [54]. Traditional handwashing with soap and water will be familiar to most patients and families. Waterless hand hygiene, typically using alcohol-based hand rubs, is more efficacious and convenient for cleaning hands that are not visibly soiled [52]. If products containing emollients are used, it can also reduce skin drying and cracking. Patients and families should be taught to wash their hands before and after manipulating any medical devices and caring for wounds. Education of patients and family members on the techniques and importance of hand hygiene during hospitalization and at the time of discharge is a simple, low-cost strategy to reduce post-discharge MRSA infections. Teaching can be incorporated into the daily care of patients by nursing and medical staff, both verbally and by example. As a horizontal infection control measure, hand hygiene education has the additional benefit of reducing infections due to all pathogens.
Role of Environmental Cleaning in the Home Setting
Multiple studies have found that the immediate environment of patients who are colonized or infected with MRSA is contaminated with the organism, with greater organism burdens associated with infected patients compared to those who are only colonized [55–59]. Greater environmental contamination is observed when MRSA is present in the urine or wounds of patients [59]. This can lead to transmission of MRSA to family members [23,60,61]. Risk factors for transmission include participation in the care of the patient, older age, and being the partner of the case patient. For the patient, there can be transmission to uninfected body sites and a cycle of recolonization and re-infection. Successful decolonization strategies have included frequent laundering of bedclothes and towels, as well as screening and decolonization of family members. While these strategies may succeed in decolonization, there is no consensus on efficacy in preventing infection in patients or family members. More research in this area is needed, particularly for decolonization strategies, which carry risk of resistance. Attention to cleanliness in the home is a basic hygiene measure that can be recommended.
Conclusion
Post-discharge MRSA infections are an important and underestimated source of morbidity and mortality. Strategies for prevention include infection control measures to prevent incident colonization during hospitalization, removal of any nonessential invasive devices, nursing care for essential devices, wound care, avoiding nonessential antimicrobial therapy, hand hygiene for patients and caregivers, and cleaning of the home environment. Decolonization therapies currently play a limited role, particularly in outbreak situations. The future research agenda should include identification of post-discharge patients who are most likely to benefit from decolonization strategies, and testing those strategies.
Corresponding author: Mary Bessesen, MD, InfectiousDiseases (111L), 1055 Clermont St., Denver, CO 80220, Mary.Bessesen@ucdenver.edu.
