Abstract and Introduction
Abstract
Pressure ulcers (PU) are a major reservoir of methicillin-resistant Staphylococcus aureus (MRSA) in hospitals. The objectives of this study were to estimate the prevalence of MRSA colonization in PU of hospitalized patients with Stage II or higher PU, to identify risk factors for colonization of these wounds, and to ascertain whether MRSA colonization of PU increases the risk of MRSA bacteremia.
Methods. This study was conducted at the Clinical Hospital of Federal University of Uberlandia, MG, Brazil. A prospective cohort study of 145 patients with Stage II or higher PU, colonized or not with MRSA, was conducted over 21 months. Infected ulcers were defined for clinical signs and for positive evaluation of smears of the wound by the ratio of polymorphonuclears to epithelial cells of ≥ 2:1, after Giemsa staining.
Results. Sixty-three (43.5%) MRSA colonized PU patients were identified, but none of the risk factors analyzed were independently associated with MRSA colonization. Among the patients with positive blood cultures and MRSA colonized PU, the odds ratio for MRSA bacteremia (OR = 19.0, 95% CI = 2.4–151.1, P < 0.001) and mortality rate (OR = 21.9, 95% CI = 1.23–391.5, P = 0.002), were high. Independent risk factors for MRSA bacteremia were: ≥ 2 underlying disease (OR = 6.26, 95% CI = 1.01–39.1, P = 0.05) and prior MRSA infected PU (OR = 12.75, 95% CI=1.22–132.9, P = 0.03).
Conclusion. The present study identifies MRSA colonized PU patients as a potential epidemiologic reservoir for this organism and a high-risk for MRSA bacteremia, which contributes to prolonged hospitalization and poor prognosis.
Introduction
Pressure ulcers (PU) develop mainly as a consequence of continued skin pressure over bony prominences. Pressure ulcers lead to the disruption of skin integrity, local tissue ischemia, and necrosis. The development of PU not only lengthens a patient's hospital stay, but also increases nurses' workload and healthcare costs. Prevalence is particularly high in critical care units (approximately 22%) and incidence ranges from 8%–40%.
Methicillin-resistant Staphylococcus aureus (MRSA) has increased in relative frequency among isolates from nosocomial infections.S aureus and the phenotype MRSA are commonly recovered from PU cultures, besides being the common cause of hospital-acquired bloodstream, surgical site, and respiratory tract infections. Pressure ulcers are, therefore, reservoirs for these organisms and may impact nosocomial infections. Some reports show the importance of PU as potential sources of bacteremia in hospitalized patients; S aureus is the most commonly isolated organism in these infections.
Standard prevention of MRSA transmission is the same as for all S aureus strains and includes good hygiene, proper hand washing, and appropriate care of skin wounds or infections, all of which reduce or prevent transmission. Nurses' hands are more easily contaminated since patients with PU are strongly associated with longer hospital stays and require more intensive care for their wound dressings. Eliminating colonization is a possible strategy for preventing infection since MRSA colonization generally precedes MRSA infection.
The objectives of this study were to estimate the prevalence of MRSA colonization in PU of hospitalized patients with Stage II or higher PU, to identify risk factors for colonization of these wounds, and to ascertain whether MRSA colonization of PU increases the risk of MRSA bacteremia in a Brazilian university hospital.