Promethazine improves antibiotic efficacy and disrupts biofilms of <i>Burkholderia pseudomallei</i> José Júlio Costa Sidrim David Caldas Vasconcelos Giovanna Barbosa Riello Glaucia Morgana de Melo Guedes Rosana Serpa Tereza de Jesus Pinheiro Gomes Bandeira André Jalles Monteiro Rossana de Aguiar Cordeiro Débora de Souza Collares Maia Castelo-Branco Marcos Fábio Gadelha Rocha Raimunda Sâmia Nogueira Brilhante 10.6084/m9.figshare.4309232.v1 https://tandf.figshare.com/articles/dataset/Promethazine_improves_antibiotic_efficacy_and_disrupts_biofilms_of_i_Burkholderia_pseudomallei_i_/4309232 <p>Efflux pumps are important defense mechanisms against antimicrobial drugs and maintenance of <i>Burkholderia pseudomallei</i> biofilms. This study evaluated the effect of the efflux pump inhibitor promethazine on the structure and antimicrobial susceptibility of <i>B</i>. <i>pseudomallei</i> biofilms. Susceptibility of planktonic cells and biofilms to promethazine alone and combined with antimicrobials was assessed by the broth microdilution test and biofilm metabolic activity was determined with resazurin. The effect of promethazine on 48 h-grown biofilms was also evaluated through confocal and electronic microscopy. The minimum inhibitory concentration (MIC) of promethazine was 780 mg l<sup>−1</sup>, while the minimum biofilm elimination concentration (MBEC) was 780–3,120 mg l<sup>−1</sup>. Promethazine reduced the MIC values for erythromycin, trimethoprim/sulfamethoxazole, gentamicin and ciprofloxacin and reduced the MBEC values for all tested drugs (<i>p</i><0.05). Microscopic analyses demonstrated that promethazine altered the biofilm structure of <i>B</i>. <i>pseudomallei</i>, even at subinhibitory concentrations, possibly facilitating antibiotic penetration. Promethazine improves antibiotics efficacy against <i>B. pseudomallei</i> biofilms, by disrupting biofilm structure.</p> 2016-12-12 14:05:13 Burkholderia pseudomallei promethazine efflux pumps resistance biofilms synergism