In Vitro Activities of Amoxicillin-Clavulanate, Doxycycline, Ceftazidime, Imipenem, and Trimethoprim-Sulfamethoxazole against Biofilm of Brazilian Strains of Burkholderia pseudomallei

Abstract

eThis study aimed at investigating the in vitro activities of amoxicillin-clavulanate, doxycycline, ceftazidime, imipenem, and trimethoprim-sulfamethoxazole against Burkholderia pseudomallei in planktonic and biofilm forms, through broth microdilution and resazurin-based viability staining, respectively. In planktonic growth, the strains were susceptible to the drugs, while in biofilm growth, significantly higher antimicrobial concentrations were required, especially for ceftazidime and imipenem, surpassing the resistance breakpoints. These results highlight the importance of the routine evaluation of biofilm antimicrobial susceptibility.

Farnesol increases the susceptibility of Burkholderia pseudomallei biofilm to antimicrobials used to treat melioidosis

“…pseudomallei (Bandeira et al . ), which leads to decreased antimicrobial susceptibility and the occurrence of clinical relapses (Limmathurotsakul et al . ), it was decided to evaluate the effects of farnesol alone and in combination with antimicrobial drugs on mature biofilms of B .…”

“…In parallel, 96‐well flat‐bottomed polystyrene microtitre plates were prepared by adding 175 μ l of BHI broth supplemented with 1% glucose (BHIGlic, Vetec, Brazil) (Bandeira et al . ). Afterwards, 25 μ l of the bacterial suspension were added to each well, and the plates were incubated at 37°C, for 48 h (Roveta et al .…”

“…; Bandeira et al . ). Staphylococcus aureus ATCC 25923 and Staphylococcus epidermidis ATCC 12228 were used as positive and negative control for biofilm formation respectively (Bandeira et al .…”

“…Each well of the microdilution plate received 300 μ l of a given drug concentration and all plates were incubated in an aerobic atmosphere, at 37°C, for 24 h (Bandeira et al . ).…”

“…The minimum biofilm erradication concentration (MBEC) was defined as the lowest concentration capable of completely inhibiting biofilm metabolic activity, which was detected by the absence of colour change suffered by resazurin (Bandeira et al . ). Finally, the content of the plate was transferred to another microplate for spectrophotometric reading, to confirm the results.…”