Abstract:For understanding the effect of OmpU on antibiotics resistance of Vibrio parahaemolyticus, a deletion mutant strain of the highly abundant outer membrane protein(OmpU) in Vibrio parahaemolyticus, designated as ΔompU, was constructed in this study. Minimum inhibitory concentration (MIC) assay revealed altered antibiotic resistances of ΔompU to 12 antibiotics, with the highest increase observed in resistance to ampicillin. Quantitative reverse transcription PCR showed a general downregulation in the transcription level of peptidoglycan synthesis genes in both wild-type (WT) and ΔompU cells under ampicillin stimulation. However, the gene VP_RS17515 encoding β-lactamase exhibited the higher transcription level in WT strains than ΔompU. The results suggest that V. parahaemolyticus responds to ampicillin through expressing β-lactamase and reducing peptidoglycan synthesis rates, while OmpU changes the cell membrane permeability to affect the penetration of ampicillin.
