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Use of a Novel Selective Medium to Detect Methicillin-Resistant Staphylococcus aureus in Colonized Patients of an Intensive Care Unit

Published online by Cambridge University Press:  02 January 2015

Cícero Gomes Dias ,
Marcos Vinícius Rosa Röpke ,
Silvana Superti ,
Laura Berquó  and
Pedro d'Azevedo
Cícero Gomes Dias*
Affiliation:
Department of Microbiology and Parasitology, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, Porto Alegre, Brazil
Marcos Vinícius Rosa Röpke
Affiliation:
Department of Microbiology and Parasitology, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, Porto Alegre, Brazil
Silvana Superti
Affiliation:
Laboratory, Hospital Mãe de Deus, Porto Alegre, Brazil
Laura Berquó
Affiliation:
Infection Control Service, Hospital Mãe de Deus, Porto Alegre, Brazil
Pedro d'Azevedo
Affiliation:
Department of Microbiology and Parasitology, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, Porto Alegre, Brazil
*
Department of Microbiology and Parasitology, Fundação Faculdade Federal de Ciências Médicas de Porto Alegre, Porto Alegre, RS, BrazilCEP: 900050-170
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Abstract

Background:

Detection of colonized patients is important for implementing control measures for methicillin-resistant Staphylococcus aureus (MRSA). Laboratory detection of MRSA carriers is increased by the use of selective screening media, helping control dissemination of such organisms.

Objective:

To evaluate three different media, including selective and nonselective media, in the detection of MRSA from clinical specimens of patients of an intensive care unit (ICU).

Patients:

Adult patients in the ICU of the Hospital Mae de Deus, Porto Alegre, Brazil.

Methods:

A total of 224 specimens were obtained from the nares of patients and plated on blood agar, mannitol sait agar containing 2 μg/mL of oxacillin (MSAO), and oxacillin resistance screening agar base (ORSAB). The presence of MRSA was investigated in typical colonies growing on the three types of media. Discrepant results were resolved by detection of the mecA gene by polymerase chain reaction and the modified penicillin binding protein known as PBP2'.

Results:

MRSA was detected in 32 (14.3%) of 224 specimens. Blood agar, MSAO, and ORSAB detected MRSA in 17, 31, and 28 specimens, respectively. After the coagulase test, no false resistance was observed.

Conclusion:

MSAO and ORSAB performed equivalently in the detection of MRSA of colonized patients and require a single supplementary test (coagulase) to confirm MRSA.

Type
Original Articles
Information
Infection Control & Hospital Epidemiology , Volume 25 , Issue 2 , February 2004 , pp. 130 - 132
Copyright
Copyright © The Society for Healthcare Epidemiology of America 2004

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