Short report
Meticillin-resistant Staphylococcus aureus: spread of specific lineages among patients in different wards at a Brazilian teaching hospital

https://doi.org/10.1016/j.jhin.2013.12.004Get rights and content

Summary

This study aimed to characterize meticillin-resistant Staphylococcus aureus (MRSA) lineages circulating in a Brazilian teaching hospital. MRSA isolates from nasal swabs were evaluated to assess antimicrobial susceptibility, staphylococcal cassette chromosome mec (SCCmec), Panton–Valentine leucocidin status, pulsed-field gel electrophoresis profile and multi-locus sequence type (MLST) analysis. Eighty-three MRSA isolates were analysed. SCCmec III (43.4%) and IV (49.4%) were predominant. ST1-IV (USA400) was more common in internal medicine (P = 0.002) whereas ‘clone M’ (SCCmec III) was more common in the medical and surgical intensive care unit (P = 0.004), and all isolates were ST5-IV (USA800) in dermatology (P < 0.001). These data improved the understanding of the MRSA epidemiology inside the hospital and helped to establish effective control measures.

Introduction

Meticillin-resistant Staphylococcus aureus (MRSA) is an important cause of healthcare-associated infections and some lineages are globally spread. Meticillin resistance is due to the mecA gene, located in a staphylococcal cassette chromosome (SCCmec); the most frequent types are I, II, III and IV.1

In Brazil, isolates related to the ‘Brazilian epidemic clone’ (BEC) multi-locus sequence type (ST) 239, SCCmec III (ST239-III) lineage were responsible for 90% of nosocomial MRSA isolates in the late 1990s.2 However, over the last decade SCCmec IV isolates have emerged in our country. Currently, ST1-IV (USA400) and ST5-IV (USA800) are the most common lineages identified in Brazilian hospitals.3, 4, 5

Studies characterizing isolates from nasal colonization of inpatients in Brazil have not been described. Here, we investigated the molecular characteristics of MRSA isolates from colonized patients in a Brazilian hospital to characterize the lineages circulating within the institution.

Section snippets

Methods

This observational study was performed between October 2005 and August 2006, at the Hospital Universitário Clementino Fraga Filho (HUCFF), a tertiary-care public teaching hospital at Rio de Janeiro, Brazil with 490 beds and 1200 patients admitted per month. Nasal swabs were collected from all patients that met at least one of the following criteria: hospitalized in wards with a high MRSA incidence (more than four new cases per 1000 patient-days); hospitalized in the same room as a newly

Results

Eighty-three MRSA-colonized patients were identified [internal medicine (IM), N = 39; medical and surgical intensive care units (MSICU), N = 15; infectious diseases (ID), N = 10; dermatology, N = 8; and others, N = 11]. SCCmec III (43.4%) and IV (49.4%) were predominant. The SCCmec II and V were each found in three isolates (3.6%).

Using standard interpretation criteria it was found that 34 pulsotypes belonged to 15 genotypes.2 ST1-IV (USA400) was the most common lineage (32.5%), followed by

Discussion

To our knowledge, this is the first study to identify distinct MRSA lineages circulating in the major units of a general hospital in Brazil. SCCmec IV isolates accounted for the majority of the MRSA nasal isolates recovered in the main units of the hospital. This high proportion differed from studies carried out in some other countries. In the USA, Tenover et al. reported SCCmec type II as the most prevalent among nasal colonization isolates from different hospitals, whereas Luo et al. reported

Conflict of interest statement

None declared.

Funding sources

This study was supported by Brazilian grants from Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Coordenação de Aperfeiçoamento Pessoal de Nível Superior (CAPES), Fundação Universitária José Bonifácio (FUJB) and Programa de Núcleos de Excelência (PRONEX).

References (12)

There are more references available in the full text version of this article.

Cited by (0)

View full text
Copyright © 2013 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.