Methods: Objective: To evaluate different antimicrobial colistin based regimens in the production of biofilm generated by MDR A. baumannii.
We used strains of MDR A. baumannii, with recognized biofilm – production phenotype; all of them showing susceptibility to colistin, according to EUCAST. After 24hrs of incubation, different combinations of antibiotics were added, then they were assigned in 3 groups as follows: Group 1 - colistin 2 mg / ml (for each experiment fixed dose); Group 2 - colistin 2 mg / ml + rifampicin 2 mg / ml and 4 mg / ml; Group 3 - colistin 2 mg / ml + meropenem 2 mg / ml and 4 mg / ml. For the generation of biofilm polystyrene microplates of 96 wells "U" were used, and then biofilm determined by crystal violet to an OD630nm. Each experiment was performed three fold.
Results: A total of 36 strains of MDR A. baumannii were studied. After monotherapy with colistin at 2 mg / ml (Group 1), the biofilm production was evident just in 16 strains (44.4%). The remaining 20 strains were then evaluated with the combination of: colistin plus rifampicin inhibiting biofilm production in 91.7% at 2 mg / ml and 97.3% at 4 mg / ml and colistin plus meropenem in 69.5% at 2 mg / ml and 86.2% at 4 mg / ml.
Conclusion: The effect of anti-biofilm production in the combination therapy with rifampicin–colistin it is similar as the already published, however the results from the combination meropenem-colistin and its directly proportional effect in biofilm production according with the dose of carbapenem used against biofilm production of MDR A. baumannii it is a good window of opportunity for the treatment of this complex rod
C. E. Lopez,
R. Hernández Castro, None
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