Evaluation of Interhospital Spread of Methicillin-Resistant Staphylococcus aureus in Sao Paulo, Brazil, Using Pulsed-Field Gel Electrophoresis of Chromosomal DNA

Abstract

To evaluate the interhospital spread of methicillin-resistant Staphylococcus aureus (MRSA) clone in Sao Paulo, we analyzed the restriction fragment length polymorphisms (RFLP) of chromosomal DNA from isolates from nine Sao Paulo hospitals. Restriction digestion of genomic DNA was performed with SmaI and the fragments were separated by pulsed-field gel electrophoresis. Only six different RFLP patterns were demonstrated among 30 MRSA isolates. Isolates possessing an identical RFLP pattern were demonstrated in eight of the nine Sao Paulo hospitals evaluated. Our results documented the widespread dissemination of a single clone of MRSA in several hospitals. Furthermore, the small clonal variability among multidrug-resistant MRSA coupled with the wide spread of this clone could make the intrahospital epidemiological evaluation of RMSA outbreaks very difficult.

New multilocus sequence typing of MRSA in São Paulo, Brazil

“…Among species of Staphylococcus, they account for 30 to 50% of nosocomial infections and this number is on the rise (2,3). After the description of the Brazilian epidemic clone (BEC) in 1992 (4), other studies further demonstrated the persistence of this microorganism in Brazilian hospitals (3). In these studies, the molecular characterization of methicillin-resistant S. aureus (MRSA) has been conducted primarily by pulsed-field gel electrophoresis (PFGE) and plasmid analysis, which showed the existence of internationally disseminated clones, reflecting epidemiological and geographical relatedness (5).…”

Type IV SCCmec found in decade old Brazilian MRSA isolates

“…This well characterised clone has been described as ST239 when typed by Multilocus Sequence Typing (MLST) [13], and carries a type III SCCmec [14]. Previous studies [15][16][17] describing the prevalence and extension of geographic dissemination of this single MRSA clone in Brazil showed it to represent close to 80% of MRSA isolates. This clone was reported as being the most frequent among MRSA isolates recovered from several hospitals from several cities located throughout Brazil's enormous territory and separated by a distance of several thousand kilometres.…”

“…Souza et al [11] also reported the predominance (97%) and persistence of this clone among isolates in Brazil. Using Pulsed Field Gel Electrophoresis (PFGE), the BEC has been broken down into different subtypes all related to one another [11], which could be explained by its maintenance in Brazil at least since 1990 [17].…”

Application of molecular techniques in the study of Staphylococcus aureus clonal evolution - A Review

“…However, Oliveira et al (2002) described the same clone as XI::B and the HC as III::B. Nevertheless, in 1994, Sader et al (1994) had already reported the occurrence of an endemic MRSA clone in eight hospitals in São Paulo city. This was named SP Clone and was probably the first report of the BC.…”