Identification of MRSA Carriers Helps Select Measures to Reduce Colonization Pressure

There are few studies in Brazil that address baseline prevalence of MRSA colonization and associated risk factors at hospital admission, or the incidence of nosocomial colonization. Helena Santos, of Hospital de Clínicas de Porto Alegre in Porto Alegre, Brazil, and colleagues, report a prospective study in a tertiary-care, university-affiliated hospital to implement a new MRSA control policy at their institution. Their research was published in BMC Infectious Diseases.

The researchers report that a cohort of randomly selected patients admitted to emergency and clinical wards at their hospital was followed until discharge. Nasal swabs were taken for identification of MRSA-colonized patients and detection of SCCmecA in positive cultures, at admission and weekly thereafter. Multivariate analysis using a log-binomial analysis was used to identify risk factors for colonization.

After screening 297 adult patients and 176 pediatric patients, the prevalence of MRSA at admission was 6.1 percent (95%CI, 3.6% to 9.4%), in the adult population and 2.3 percent (95%CI, 0.6% to 5.7%), for children. From multivariate analysis, the risk factors associated with colonization in adults were: age above 60 years (P = 0.019) and hospitalization in the previous year (P = 0.022). Incidence analysis was performed in 276 MRSA-negative patients (175 adults and 101 children). Acquisition rate was 5.5/1,000 patient-days for adults (95%CI, 3.4 to 8.5/1,000 patients-days), and 1.1/1,000 patient-days for children (95%CI, 0.1 to 4.0/1,000 patients-days).

The researchers conclude that identification of MRSA carriers is a step toward establishing a control policy for MRSA, and helps to identify measures needed to reduce colonization pressure and to decrease the high acquisition rate in hospitalized patients.

Reference: Santos HB, Machado DP, Camey SA, Kuchenbecker RS, Barth AL and Wagner MB. Prevalence and acquisition of MRSA amongst patients admitted to a tertiary-care hospital in Brazil. BMC Infectious Diseases 2010, 10:328doi:10.1186/1471-2334-10-328