Comparative proteomic analysis of sensitive and multi-drug resistant Aeromonas hydrophila isolated from diseased fish

Bacterial hemorrhagic septicemia caused by multi-drug resistant (MDR) Aeromonas hydrophila has exponentially increased in the past decade, and reached an alarming rate making it a major concern in the aquaculture industry in China. The aim of this study was to investigate the difference in the regulation of proteins expression in multi-drug resistance and susceptible A. hydrophila strains isolated from diseased fish using two-dimensional electrophoresis (2-DE) combined with mass spectrometry. 28 isolates of A. hydrophila were successfully identified by biochemical tests. Antibiotic susceptibility test results showed that all the isolates have different drug resistant patterns. A total of 61 and 17 differently expressed proteins were identified in MDR and susceptible A. hydrophila, respectively, evidencing that biological processes related to carbon metabolism, biosynthesis of secondary metabolites, microbial metabolism in diverse environments, cationic antimicrobial peptide (CAMP) resistance and propanoate metabolism were down-regulated in MDR strain, while proteins involved in biosynthesis of antibiotics, glycolysis/gluconeogenesis were highly expressed in the sensitive strain. The analysis of differentially expressed proteins from multi-drug resistance and susceptible strains suggests that a number of proteins are involved in several metabolic metabolism pathways plays an important role in A. hydrophila drug resistance. Our findings provide new insights about mechanisms involved in drug resistance and propose possible novel targets for developing alternative antibacterial drugs.