Characterization of the clonal profile of MRSA isolated in neonatal and pediatric intensive care units of a University Hospital.
BACKGROUND
Methicillin-resistant Staphylococcus aureus (MRSA) are important pathogens in neonatal and pediatric intensive care units, which can cause severe infections in hospitalized children. Detection of the mecA gene and classification of the staphylococcal cassette chromosome mec (SCCmec) permit the characterization of MRSA strains isolated from infections caused by these microorganisms. In contrast, pulsed-field gel electrophoresis (PFGE) is used to type MRSA clones. This method is commonly used to analyze the epidemiology of bacteria causing nosocomial infections. The objective of this study was to detect and characterize MRSA isolated from clinical specimens of children hospitalized in the neonatal and pediatric intensive care units of the University Hospital of the Botucatu Medical School.


METHODS
A total of 119 S. aureus strains were isolated from clinical specimens and the mecA gene was detected by PCR. SCCmec was detected by multiplex PCR and the clonal profile was analyzed by PFGE.


RESULTS
The mecA gene was detected in 17.6% (21/119) of the isolates; 42.9% (9/21) of MRSA were characterized as SCCmec type III and 57.1% (12/21) as type IV. Analysis of the clonal profile of these strains revealed three distinct clones, with SCCmec type III being related to the Brazilian endemic clone and type IV to clones JCSC4469 and USA800.


CONCLUSIONS
Replacement of clonal groups occurred in the neonatal and pediatric units over the period studied, a fact highlighting the importance of improving hygiene practices and control measures of nosocomial infections in these units.
Laboratory of Bacteriology, Department of Microbiology and Immunology, Institute of Biosciences, UNESP - Univ Estadual Paulista, Botucatu, São Paulo, CEP 18618-970, Brazil. cataneli@ibb.unesp.br.
Valéria Cataneli
VC
Pereira
Laboratory of Bacteriology, Department of Microbiology and Immunology, Institute of Biosciences, UNESP - Univ Estadual Paulista, Botucatu, São Paulo, CEP 18618-970, Brazil. danilo.riboli@ibb.unesp.br.
Danilo Flávio Moraes
DF
Riboli
Laboratory of Bacteriology, Department of Microbiology and Immunology, Institute of Biosciences, UNESP - Univ Estadual Paulista, Botucatu, São Paulo, CEP 18618-970, Brazil. cunhamlr@ibb.unesp.br.
Maria de Lourdes Ribeiro de Souza
Mde L
da Cunha
D000293:Adolescent; D001426:Bacterial Proteins / Q000235:genetics; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D015278:Intensive Care Units, Pediatric; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D058889:Molecular Typing; D046915:Penicillin-Binding Proteins; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology
D001426:Bacterial Proteins; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus