Sub-inhibitory concentrations of penicillin G induce biofilm formation by field isolates of Actinobacillus pleuropneumoniae

摘要: Abstract Actinobacillus pleuropneumoniae is a Gram-negative bacterium and causative agent of porcine pleuropneumonia. This highly contagious disease that causes important economic losses to the swine industry worldwide. Penicillins are extensively used in production these antibiotics associated with high systemic clearance low oral bioavailability. may expose A. sub-inhibitory concentrations penicillin G when antibiotic administered orally. Our goal was evaluate effect sub-minimum inhibitory concentration (MIC) on biofilm formation pleuropneumoniae. Biofilm 13 field isolates from serotypes 1, 5a, 7 15 tested presence sub-MIC using polystyrene microtiter plate assay. Using microscopy techniques enzymatic digestion, architecture composition were also characterized after exposure G. Sub-MIC significantly induced nine isolates. The G-induced biofilms contained more poly-N-acetyl- d -glucosamine (PGA), extracellular DNA proteins compared control grown without Additionally, sensitive DNase which not observed untreated controls. Furthermore, up-regulated expression pgaA, encodes protein involved PGA synthesis, genes encoding envelope-stress sensing two-component regulatory system CpxRA. In conclusion, sub-MICs induce this likely result cell envelope stress sensed by CpxRA resulting an increased other matrix components.