Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/22338

TitleVirulence gene expression by staphylococcus epidermidis biofilm cells exposed to antibiotics
Author(s)Gomes, F. I.
Teixeira, P.
Cerca, Nuno
Ceri, Howard
Oliveira, Rosário
Issue date2011
PublisherMary Ann Liebert
JournalMicrobial Drug Resistance
Abstract(s)Staphylococcus epidermidis have become important causes of nosocomial infections, as its pathogenesis is correlated with the ability to form biofilms on polymeric surfaces. Production of poly-N-acetylglucosamine (PNAG) is crucial for S. epidermidis biofilm formation and is synthesized by the gene products of the icaADBC gene cluster. Production of PNAG/polysaccharide intercellular adhesin and biofilm formation are regulated by the alternative sigma factor, σB, and is influenced by a variety of environmental conditions including disinfectants and other antimicrobial substances. The susceptibility of five S. epidermidis strains to antibiotics alone and in double combination was previously tested. Our results demonstrated that some combinations are active and present a general broad spectrum against S. epidermidis biofilms, namely rifampicin–clindamycin and rifampicin–gentamicin. In the present study, it was investigated whether the combination of rifampicin with clindamycin and gentamicin and these antibiotics alone influence the expression of specific genes (icaA and rsbU) of S. epidermidis within biofilms using real-time polymerase chain reaction. The data showed that in most cases the expression of both genes tested significantly increased after exposure to antimicrobial agents alone and in combination. Besides having a similar antimicrobial effect, rifampicin combined with clindamycin and gentamicin induced a lower expression of biofilm-related genes relatively to rifampicin alone. Associated with the advantage of combinatorial therapy in avoiding the emergence of antibiotic resistance, this study demonstrated that it can also cause a lower genetic expression of icaA and rsbU genes, which are responsible for PNAG/polysaccharide intercellular adhesin production, and consequently reduce biofilm formation recidivism, relatively to rifampicin alone.
TypeArticle
URIhttp://hdl.handle.net/1822/22338
DOI10.1089/mdr.2010.0149
ISSN1076-6294
Other identifiers1931-8448
Peer-Reviewedyes
AccessOpen access
Appears in Collections:CEB - Publicações em Revistas/Séries Internacionais / Publications in International Journals/Series

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