Analysis of different molecular methods for typing methicillin-resistant Staphylococcus aureus isolates belonging to the Brazilian epidemic clone

Abstract

The extensive geographic spread of MRSA isolates belonging to the Brazilian epidemic clone (BEC) limited the value of pulsed-®eld gel electrophoresis (PFGE) in epidemiological studies of outbreaks caused by these strains. Thus, the discriminatory power of eight different molecular methods was evaluated in an attempt to establish a methodology for genotyping BEC isolates involved in intra-hospital outbreaks. BEC isolates from ®ve hospitals in Teresina City, Piauõ Â State were genotyped by conventional electrophoresis or PFGE of Cla I-or Sma I-digested genomic DNA hybridised with speci®c labelled mecA, Tn554, IS257 and IS256 probes. The combination of PFGE with Cla I/mecA, Cla I/Tn554, Cla I/IS257, Sma I/mecA and Sma I/IS257 probe-®ngerprinting techniques provided a very poor discriminatory power for BEC strains. Although Cla I/ IS256 ®ngerprinting discriminated 17 different polymorphisms among the isolates displaying PFGE A 1 pattern, this strategy was not reproducible. In contrast, the combination of PFGE and Sma I/IS256 polymorphisms differentiated BEC isolates into nine stable polymorphisms. Thus combination of PFGE and hybridisation with IS256 probe may be recommended as a useful means of typing BEC strains involved in intrahospital infections.

Molecular typing of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in two metropolitan areas of São Paulo State, southeast Brazil

“…This approach would be able to show a possible clonal variability in these MRSA strains that was not demonstred in previously published works [16][17][18].…”

“…Four strains (257A, 20COA, 256B, and 24COA) also obtained in the Medical School Hospital of Campinas State University were considered in this work as representative strains of a previously described work [20]. As control strains and for comparison sake in the clustering analysis, another 2 strains (BEC 9393; HC 562) [17] were used.…”

“…A second multiresistant clone (Brazilian Epidemic clone -BEC) was shown to be widely spread in Brazilian hospitals several thousands of kilometers apart [11] and later it was also associated with infections in Portugal, Argentina, Uruguay, Czech Republic, and Canada [12][13][14][15]. Several other studies [16][17][18] in Brazil, using pulsed-field gel electrophoresis (PFGE) technique, to analyze Brazilian MRSA strains, also indicated a low variability between strains.…”

Otimização do processo de extração de própolis através da verificação da atividade antimicrobiana

“…Bactéria: Uma cepa de Staphylococcus aureus multirresistente pertencente ao clone epidêmico brasileiro foi utilizada neste estudo 17 . Esta bactéria foi gentilmente cedida pelo laboratório de Biologia Molecular de Bactérias (IMPPG -UFRJ) onde o seu perfil de sensibilidade foi determinado, apresentando resistência à maioria dos antibióticos utilizados na prática clínica, sendo sensível apenas a vancomicina.…”

New method for early detection of two random amplified polymorphic DNA (RAPD) groups of Staphylococcus aureus causing bovine mastitis infection in Paraná State, Brazil

“…Fragments were prepared according to the pGEM® Systems, (Promega Corporation) and cloning in the E. coli TOP10 F1 (Soares et al, 2001). For visualization of the possible insertion fragments in the plasmids, eletrophoresis in agarose gel (0.8 %) was carried out after the treatment with EcoRI restriction enzyme (Invitrogen Life).…”