Resumo

Staphylococcus haemolyticus has emerged as an important pathogen in human diseases, and among coagulase-negative staphylococci (CoNS), it is the second most frequently specie isolated from human blood cultures. However, its pathogenic potential and its virulence factors are still underexplored. Recently, genome sequencing of the Staphylococcus aureus ST239 strain revealed a novel gene, which function is still unknown, encoding a surface protein of 15 kDa, named SasX. Another protein, named SesI, with a high similarity has been also found in Staphylococcus epidermidis RP62A strain. In both cases the proteins demonstrated to be involved in pathogenesis, especially adhesion and invasion of host cell. The aim of the current study is to extend this research to Staphylococcus haemolyticus. For this, 62 S. haemolyticus strains were isolated from patients at Hospital Naval Marcílio Dias, Rio de Janeiro, between 2006 and 2008. The presence of a gene encoding for a protein similar to SasX were analyzed by PCR. A fragment of the gene was detected in 33 samples (53.22%) and 2 of them were sequenced. The sequences were similar with sasX (95%) and sesI (98%), previously described in S. aureus and S. epidermidis respectively. The full sequence and the genetic context of the sasX-like gene in the S. haemolyticus genome are being determinated. The expression of the gene sasX-like will be also evaluated in order to prove that the detectable genes are functional. The description of a new protein probably involved in the pathogenesis of S. haemolyticus will be valuable in elucidating the virulence factors of this pathogen and may be a new target for therapeutic action providing even more promising developments. CNPq, FAPERJ and CAPES