Six genes of ompA family shuffling for development of polyvalent vaccines against Vibrio alginolyticus and Edwardsiella tarda

Summary Although many typical outer‐membrane proteins (OMPs) have been well characterized, the biological functions of many OMPs remain largely elusive. In this study, we successfully constructed 29 OMP knockout strains in the pathogen Aeromonas hydrophila, which account for about 50% of all predicted OMPs in this bacterial species. We then further validated the antibiotics' susceptibility characteristics against 20 antimicrobial reagents in these mutants considering several phenotypes. Our results showed that a total of 22 OMP mutants affected the susceptibility to at least one antibiotic. The deletion of some OMPs, such as ΔlamB and ΔbamA, revealed very important roles in the resistance to certain antibiotics. However, not a single OMP mutant presented a constant behaviour to all of the tested antibiotics, suggesting the existence of a complex intercellular regulation mechanism and a protein–protein interaction network underlying the OMP homeostasis in the presence of antibiotics. Meanwhile, some OMP mutants also affected biofilm formation, ECPase and haemolytic activity, and carbon resources utilization. This report demonstrates the biological functions of OMPs on a large scale and most of results have not been reported in A. hydrophila.

Section: Discussionmentioning

confidence: 97%

The characteristics of antibiotic resistance and phenotypes in 29 outer‐membrane protein mutant strains in Aeromonas hydrophila

Wang

et al. 2019

“…QRT-PCR was carried out as described previously (Li et al, 2016;Cheng et al, 2018). Total RNA was isolated from V. alginolyticus using TRIZOL regent (Invitrogen Life Technologies) according to the protocol.…”

Section: Analysis Of Gene Expressionmentioning

confidence: 99%

NaCl promotes antibiotic resistance by reducing redox states in Vibrio alginolyticus

Yang

Zeng

Yang

et al. 2018

Self Cite

Summary The development of antibiotic resistance in Vibrio alginolyticus represents a threat to human health and fish farming. Environmental NaCl regulation of bacterial physiology is well documented, but whether the regulation contributes to antibiotic resistance remains unknown. To explore this, we compared minimum inhibitory concentration (MIC) of V. alginolyticus cultured in different media with 0.5%–10% NaCl, and found that the MIC increased as the NaCl concentration increased, especially for aminoglycoside antibiotics. Consistent with this finding, internal NaCl also increased, while intracellular gentamicin level decreased. GC–MS‐based metabolomics showed different distributions of pyruvate cycle intermediates among 0.5%, 4% and 10% NaCl. Differential activity of enzymes in the pyruvate cycle and altered expression of Na(+)‐NQR led to a reducing redox state, characterized by decreased levels of NADH, proton motive force (PMF) and ATP. Meanwhile, NaCl negatively regulated PMF as a consequence of the reducing redox state. These together are responsible for the decreased intracellular gentamicin level with the increased external level of NaCl. Our study reveals a previously unknown redox state‐dependent mechanism regulated by NaCl in V. alginolyticus that impacts antibiotic resistance.

“…The antibiotic‐independent method includes vaccines, metabolome‐reprogramming molecules, phage therapy and antibacterial peptides (Peng et al ., ; Chen et al ., ; Du et al ., ; Pires et al ., ; Wang et al ., ; Zeng et al ., ; Zhang et al ., ; Jiang et al ., ). Vaccines stimulate the host's active immunity against bacterial pathogens (Guo et al ., ; Cheng et al ., ; Peng et al ., ). Metabolome‐reprogramming molecules reprogram host's anti‐infective metabolome that enhances innate immune responses (Yang et al ., ; Cheng et al ., ; Jiang et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Reduced redox‐dependent mechanism and glucose‐mediated reversal in gentamicin‐resistant Vibrio alginolyticus

Zhang

Wang

Jiang

et al. 2019

Self Cite

Summary Strategy of managing antibiotic‐resistant Vibrio alginolyticus, a bacterial pathogen that threatens human health and animal farming, is not available due to the lack of knowledge about the underlying mechanism of antibiotic resistance. Here, we showed that gentamicin‐resistant V. alginolyticus (VA‐RGEN) has four mutations on metabolism and one mutation on a two‐component system by whole‐genome and PCR‐based sequencing, indicating the metabolic shift in VA‐RGEN. Thus, metabolic profile was investigated by GC–MS based metabolomics. Glucose was identified as a crucial biomarker, whose abundance was decreased in VA‐RGEN. Further analysis with iPath, and gene expression and enzyme activity of the pyruvate cycle (the P cycle) demonstrated a global depressed metabolic pathway network in VA‐RGEN. Consistently, NADH, sodium‐pumping NADH:ubiquinone oxidoreductase (Na(+)‐NQR) system, membrane potential and intracellular gentamicin were decreased in VA‐RGEN. These findings indicate that the reduced redox state contributes to antibiotic resistance. Interestingly, exogenous glucose potentiated gentamicin to efficiently kill VA‐RGEN through the promotion of the P cycle, NADH, membrane potential and intracellular gentamicin. The potentiation was further confirmed in a zebrafish model. These results indicate that the gentamicin resistance reduces the P cycle and Na(+)‐NQR system and thereby decreases redox state, membrane potential and gentamicin uptake, which can be reversed by exogenous glucose.