Susceptibility of Staphylococcus aureus strains toward combinations of oxacillin-2,4-dihydroxychalcone.
In order to determine the existence of synergism of the bacteriostatic action of flavonoids against G(+) bacteria between a clinically interesting conventional antibiotic and a flavonoid, combinations of oxacillin (OXC) and 2,4-dihydroxychalcone (DCH) as enhancer were assayed against methicillin-sensitive Staphylococcus aureus ATCC 29 213 and methicillin-resistant S. aureus ATCC 43 300. Using a kinetic-turbidimetric method, growth kinetics was monitored in a broth containing variable amounts of OXC alone and combinations of variable OXC-constant DCH. The minimum inhibitory concentrations (MIC) of OXC alone and in combination with DCH were evaluated. For the 29 213 strain, OXC MIC was 25 microg/mL, while combinations of 2-8 microg/mL OXC with 10 microg/mL of DCH totally inhibited growth and showed synergism. The resistance of the 43 300 strain in the presence of OXC was verified; OXC-DCH combinations decreased bacterial growth by 35 %. DCH augments the action of OXC against methicillin-susceptible S. aureus and therefore constitutes a good bacteriostatic agent for methicillin-resistant S. aureus.
Laboratory of Physical Chemistry, Department of Chemistry, San Luis National University, San Luis, Argentina.
J M
JM
Talia
M A
MA
Alvarez
N B
NB
Debattista
N B
NB
Pappano
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D047188:Chalcones / Q000494:pharmacology*; D004347:Drug Interactions; D006801:Humans; D008826:Microbial Sensitivity Tests; D009391:Nephelometry and Turbidimetry; D010068:Oxacillin / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
D000900:Anti-Bacterial Agents; D047188:Chalcones; C059354:2',4'-dihydroxychalcone; D010068:Oxacillin