Isolation of methicillin-resistant coagulase-negative staphylococci from patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and comparison of different molecular techniques for discriminating isolates of Staphylococcus epidermidis

Marques de Mattos, Elaine; Arneiro Teixeira, Lenise; Morgado Alves, Vanda Maria; Ferreira Rezenda e Resende, Cleide Aparecida; da Silva Coimbra, Marcus Vinícius; da Silva-Carvalho, Maria C.ícera; Ferreira-Carvalho, Bernadete Teixeira; Sá Figueiredo, Agnes Marie

doi:10.1016/S0732-8893(02)00477-7

« Previous Next »Diagnostic Microbiology & Infectious Disease
Volume 45, Issue 1 , Pages 13-22, January 2003

Isolation of methicillin-resistant coagulase-negative staphylococci from patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and comparison of different molecular techniques for discriminating isolates of Staphylococcus epidermidis

Elaine Marques de Mattos
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Lenise Arneiro Teixeira
- Laboratório de Tecnologia de Produtos Naturais, Faculdde de Farmácia, Universidade Federal Fluminense, Rio de Janeiro, Brazil
Vanda Maria Morgado Alves
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Cleide Aparecida Ferreira Rezenda e Resende
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Marcus Vinícius da Silva Coimbra
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Hospital das Forças Aéreas do Galeão, Rio de Janeiro, Brazil
Maria C.ícera da Silva-Carvalho
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Bernadete Teixeira Ferreira-Carvalho
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
Agnes Marie Sá Figueiredo
- Laboratório de Biologia Molecular de Bactérias, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Corresponding author. Tel.: +021-2260-4193; fax: +021-2560-8028.

Received 16 April 2002; accepted 19 August 2002.

Abstract

Coagulase-negative staphylococci (CNS) have emerged as an important pathogen in nosocomial infections. About 80%–90% of CNS isolates associated with hospital infections are methicillin-resistant coagulase-negative staphylococci (MRCNS). The aims of this study were to screen for MRCNS isolates in the flora of a small population of patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and to evaluate the discriminatory power of different molecular methods: pulsed-field gel electrophoresis (PFGE), mecA location, ClaI/mecA polymorphism and arbitrarely primed polymerase chain reaction (AP-PCR) for characterizing isolates of methicillin-resistant Staphyloccus epidermidis (MRSE). Seventy-nine CNS isolates were recovered from the 11 CAPD patients studied. Using a methicillin screening agar and a DNA specific mecA probe we verified that 30 of the 79 (38%) CNS isolates were resistant to methicillin (MRCNS). Twenty-two of the 30 MRCNS (73%) were MRSE, 7 (23%) methicillin-resistant S. haemolyticus (MRSH_ae) and 1 (3%) methicillin-resistant S. hominis (MRSH_om). All patients analyzed carried MRCNS in their flora, in one or more sites. Since CAPD patients have high risk for developing peritonitis, the colonization of these patients with MRCNS might represent an adittional problem, due to the therapeutic restrictions imposed by these multiresistant isolates. A wide genetic diversity was verified when the PFGE of the MRSE isolates was analyzed. The 22 MRSE isolates displayed a total of 15 PFGE different patterns (11 PFGE types and 4 subtypes). The location of mecA in the SmaI-fragmented genome DNA did not bring any additional advantage for epidemiologic characterization of the isolates. The ClaI/mecA polymorphism was able to correctly discriminate 12 from the 15 PFGE patterns. In addition, the DNA of 20 MRSE isolates were used for AP-PCR typing. These isolates belonged to 14 PFGE patterns (11 types and 3 subtypes) and displayed 15 genotypes (for the association of PFGE, mecA location and ClaI/mecA polymorphism). A total of 17 different amplification patterns was verified using the primer 1. Only for 2 genotypes, strains having identical genetic backgrounds were further discriminated by AP-PCR (2 of 15 genotypes (87%) for AP-PCR and 1 of 15 genotypes for PFGE; (93%). Concluding, our results indicated that the AP-PCR can be an alternative and useful tool for monitoring and genotyping MRSE colonization and also to molecular characterizing MRSE outbreaks in hospitals.