Mupirocin- and methicillin-resistant Staphylococcus aureus spreading in an intermediate-care unit in a Brazilian hospital

Mupirocin resistance among methicillin-resistant Staphylococcus aureus-colonized patients at admission to a tertiary care medical center

All patients admitted to our tertiary care hospital from 1 December 2007 to 10 June 2008 were screened for methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) nasal colonization, and the isolates were tested for mupirocin susceptibility by using Etest. Mupirocin resistance (MR) was noted to occur in 3.4% of MRSA carriers, and high-level MR was noted to occur in 0.62% of carriers.

Decrease in the incidence of mupirocin resistance among methicillin-resistant Staphylococcus aureus in carriers from an intensive care unit

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious nosocomial problem, globally distributed. Decolonization with mupirocin can be used to control its dissemination.

OBJECTIVE

To determine the incidence of mupirocin resistance among MRSA carriers from an intensive care unit.

METHODS

We obtained 2723 nasal swabs during 3 years. Resistance to methicillin and mupirocin were verified (agar diffusion and the E test) and confirmed by polymerase chain reaction (PCR) (mecA for methicillin; ileS-2 and mupA for mupirocin). Plasmid-curing procedure and pulsed-field gel electrophoresis (PFGE) were employed in isolates exhibiting high resistance to mupirocin (HR-Mup) and in other selected organisms.

RESULTS

The overall incidence of HR-Mup among MRSA carriers during the studied period was 4.84% (8/165); however, the incidence decreased from 13.04% (6/46) in the first year to 3.5% (2/57) in the second year and was 0% in the last year (P = .02). LR-Mup, in contrast, increased significantly (P = .01).

CONCLUSION

Plasmid-curing procedure showed the plasmid location of genes responsible for HR-Mup. PFGE demonstrated that most MRSA, including the isolates with HR-Mup, were genetically related. The decline in HR-Mup may be attributable to the plasmid location of genes (ileS-2/mupA) and to the fact that all patients colonized with HR-Mup MRSA died or were discharged in a relatively short period of time.

Searching the health care literature efficiently: from clinical decision-making to continuing education

Searching the health care literature is an activity in which infection control professionals must routinely engage to seek evidence-based answers to specific practice questions and to stay abreast of developments in the field. Without the appropriate tools, the tremendous volume of clinical literature makes both of these daunting tasks. In this article, we illustrate techniques for searching MEDLINE efficiently, both as a means of answering particular clinical questions and for generating periodic updates on topics of general interest. With use of a specific example relevant to infection control, we demonstrate the identification of appropriate Medical Subject Headings terms that capture a given question or topic and the development of effective searches with use of these terms. We also touch on the advantages of targeting systematic reviews and meta-analyses in searching for evidence and staying abreast of the literature in general.