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Antimicrobial synergism against different lineages of methicillin‐resistant S taphylococcus aureus carrying SCC mec IV
Author(s) -
Matos P.D.M.,
Sedaca S.,
Ferreira D.C.,
Iorio N.L.,
Toledo V.C.S.,
Freitas A.I.C.,
Coelho F.L.,
Sousa C.,
Santos K.R.N.,
Pereira M.O.
Publication year - 2014
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12472
Subject(s) - library science , medical school , microbiology and biotechnology , medicine , political science , biology , medical education , computer science
Aim To evaluate the synergistic activity of antimicrobial drugs against lineages of methicillin‐resistant S taphylococcus aureus ( MRSA ) carrying SCC mec IV . The biofilm production and related genes were also detected. Methods and Results Forty two MRSA isolates were tested for biofilm production and related genes. B iofilm/biomass susceptibility to gentamicin ( G ), linezolid ( L ), rifampicin ( R ) and vancomycin ( V ) was determined for six isolates from three lineages prevalent in R io de J aneiro hospitals in concentrations ranging from 0·25 to 64 μ g ml −1 . Biomass was evaluated by microtitre plate test and number of viable cells (CFU cm −2 ) and inspected by epifluorescence microscopy. All isolates presented the ica A and sas G genes, but only 38% were biofilm producers. There were 50 and 45% biomass reductions when concentrations ≥4 μ g ml −1 of R or L and ≥16 μ g ml −1 of G or V, respectively, were used. Synergism tests produced a 55% biomass reduction with R 2 μ gml − 1 + G 16 μ gml − 1, R 2 μ gml − 1 + L 2 μ gml − 1, R 2 μ gml − 1 + V 4 μg ml− 1, and L 2 μ gml − 1 + V 4 μ gml − 1. Number of viable cells was reduced from 2 to 3 logs with R 2 μ gml − 1 + L 2 μ gml − 1and R 2 μ gml − 1 + V 4 μ gml − 1. Conclusions Synergisms involving R plus L and R plus V caused important reductions in biofilm/biomass and the number of viable cells. Drug combinations should be considered in the chemotherapies of MRSA ‐ SCC mec IV infections. Significance and Impact of the Study Biofilms in MRSA infections restrict the clinical choice of antimicrobials. Thus, knowledge of the best options for monotherapy and drug synergisms could improve clinical results.