Drug Resistance in Biofilm and Planktonic Cells of Achromobacter spp., Burkholderia spp., and Stenotrophomonas maltophilia Clinical Isolates.

Background: Biofilm production in nonfermenting Gram-negative bacteria influences drug resistance. The aim of this work was to evaluate the effect of different antibiotics on biofilm eradication of clinical isolates of Achromobacter , Burkholderia , and Stenotrophomonas maltophilia . Methods: Clinical isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry in a third-level hospital in Monterrey, Mexico. Crystal violet staining was used to determine biofilm production. Drug susceptibility testing was determined by broth microdilution in planktonic cells and biofilm cells. Results: Resistance in planktonic cells was moderate to trimethoprim-sulfamethoxazole, and low to chloramphenicol, minocycline, levofloxacin ( S. maltophilia and Burkholderia ), ceftazidime, and meropenem ( Burkholderia and Achromobacter ). Biofilm eradication required higher drug concentrations of ceftazidime, chloramphenicol, levofloxacin, and trimethoprim-sulfamethoxazole than planktonic cells ( p < 0.05). Levofloxacin showed biofilm eradication activity in S. maltophilia, minocycline and meropenem in Burkholderia , and meropenem in Achromobacter . Conclusions: Drug resistance increased due to biofilm production for some antibiotics, particularly ceftazidime and trimethoprim-sulfamethoxazole for all three pathogens, chloramphenicol for S. maltophilia and Burkholderia, and levofloxacin for Burkholderia. Some antibiotics could be used for the treatment of biofilm-associated infections in our population, such as levofloxacin for S. maltophilia, minocycline and meropenem for Burkholderia , and meropenem for Achromobacter .