Synergy between polypyrrol and benzoic acid against antibiotic-resistant Salmonella spp.
Dino César Pereira Garcez, Gabrielle Ribeiro, Marcelo Kominkiewicz, Mateus Matiuzzi da Costa, Roberta Torres Chideroli, Danillo Sales Rosa, Isaac Emanuel Pereira dos Santos, Vitor Hugo Penariol Morante, Simone Silveira, Lilian Kolling Girardini- Applied Microbiology and Biotechnology
- General Medicine
- Biotechnology
Abstract
Aims
The purpose was to characterize Salmonella Heidelberg (SH) and Minnesota (SM) isolates in terms of their resistance and persistence profile and to assess the antimicrobial effect of benzoic acid (BA) and polypyrrole (PPy).
Methods and results
The 20 isolates from broiler litter drag swabs were submitted to antibiogram and efflux pump expression. The minimum inhibitory/bactericidal concentration (MIC/MBC) of the compounds, synergistic activity, time kill, biofilm production, presence of related genes and molecular docking between compounds and bacterial target sites were evaluated. All isolates showed multi-drug resistance (MDR) and BA and PPy showed mean MIC (1 750 and 342 µg ml −1) and MBC (3 167 and 1 000 µg ml −1), respectively. None of the isolates expressed an efflux pump. The compounds showed synergism against an SH isolate and reduced the count by 3 logs in the presence of the compounds after 4 h. Most isolates (16/20) produced weak to moderate biofilm and 17 showed genes related to biofilm. The compounds interacted with two essential proteins, 3,4-dihydroxy-2-butanone 4-phosphate synthase proteins and ferritin-like domain-containing protein, in bacterial metabolism at different target sites.
Conclusions
It can be concluded that BA and PPy showed activity on SH and SM, MDR and biofilm producers, with a potential synergistic effect.