J Pediatr Infect Dis 2008; 03(01): 047-050
DOI: 10.1055/s-0035-1556960
Original Article
Georg Thieme Verlag KG Stuttgart – New York

Evaluation of accuracy and cost of four different methods for detection of methicillin resistance in Staphylococcus aureus isolates from pediatric patients hospitalized in Brazil

Marcelo Jenné Mimica
a  Department of Pediatrics, Santa Casa University Hospital, Sao Paulo, SP, Brazil
,
Eitan Naaman Berezin
a  Department of Pediatrics, Santa Casa University Hospital, Sao Paulo, SP, Brazil
,
Rozane de Lima Bigelli Carvalho
b  Department of Pathology, Santa Casa University Hospital, Sao Paulo, SP, Brazil
,
Eliana Schneider
b  Department of Pathology, Santa Casa University Hospital, Sao Paulo, SP, Brazil
,
Hélio Hehl Caiaffa-Filho
b  Department of Pathology, Santa Casa University Hospital, Sao Paulo, SP, Brazil
c  Laboratory of Medical Investigation, LIM 03, Hospital das Clinicas-FMUSP, Sao Paulo, SP, Brazil
› Author Affiliations

Subject Editor:
Further Information

Publication History

25 June 2007

10 December 2007

Publication Date:
28 July 2015 (online)

Abstract

We studied 70 pediatric clinical isolates of Staphylococcus aureus to perform a comparison of different methods for detection of methicillin-resistant S. aureus (MRSA) using polymerase chain reaction for mecA as the “gold standard” assay. The isolates were tested with oxacillin and cefoxitin discs, oxacillin agar screening plate and E-test. Of the 70 strains, 43 were mecA-positive and 27 mecA-negative. Oxacillin agar screening plate and E-test had 100% sensitivity and specificity for the presence of mecA gene. We found a specificity of 96% for both disc-diffusion methods, and sensitivities of 95% (oxacillin disc) and 93% (cefoxitin disc). However, with the new Clinical and Laboratory Standards Institute 2007 cefoxitin breakpoints the sensitivity of this method would be increased to 100%, without any decrease in specificity. These results show how important is the evaluation of the available microbiological methods by different laboratories in different settings.