Molecular variations in Vibrio alginolyticus and V. harveyi in shrimp-farming systems upon stress

Abstract

A study was performed to investigate the genomic variations in the shrimp farm isolates of Vibrio alginolyticus and V. harveyi when the isolates were subjected to environmental stress. Samples of shrimps, water and sediment were collected from Southern Indian coastal shrimp farms. Vibrio isolates were biochemically identified and confirmed using 16S rDNA and gyrB gene specific PCR. The bacterial strains were genotyped by PCR fingerprinting using GTG(5) and IS (Insertion Sequence) primers. Seven strains each of V. alginolyticus and V. harveyi were subjected to 10 passages through trypticase soya broth (TSB), which contained different NaCl concentrations (3, 6 and 8%) and trypticase soya agar (TSA). V. alginolyticus was also passaged through TSB with a 12% NaCl concentration. PCR fingerprinting, which was performed on the strains that were passaged through different salt concentrations, confirmed that V. alginolyticus and V. harveyi could affect the genomic variations, depending on the environmental conditions of the culture. The study highlights the complex genotypic variations that occur in Vibrio strains of tropical aquatic environment because of varied environmental conditions, which result in genetic divergence and/or probable convergence. Such genetic divergence and/or convergence can lead to the organismal adaptive variation, which results in their ability to cause a productive infection in aquatic organisms or generation of new strains.

NaCl promotes antibiotic resistance by reducing redox states in Vibrio alginolyticus

“…Several lines of evidences indicate that V. alginolyticus has developed several strategies to cope with antibiotics, including gene mutation of target proteins, transfer of antibiotic resistance plasmids, decrease in permeability, and activation of an efflux system such as TolC (Hayashi et al, 2002;Xiong et al, 2010;Lajnef et al, 2012;Li et al, 2012;Giedraitiene et al, 2011;Miller et al, 2014). V. alginolyticus lives in the optimum salt concentration ranging from 2.5% to 4.5% NaCl (average NaCl concentrations in the sea are~3.5%) but can survive in a wide range of NaCl concentrations from 0.5% to 12% NaCl (Santhyia et al, 2015;Liu et al, 2004), where the range of 0.5% to 4% NaCl is the conventional environmental condition under which Vibrio species survive. Thus, it is interesting to explore whether NaCl concentration affects the antibiotic resistance in Vibrio species.…”

Transcriptome analysis of Fenneropenaeus merguiensis in response to Vibrio proteolyticus infection

“…SEM images showed that it was short‐rod‐shaped with a curved body and no budding spores, pods and flagella. Vibrio , as an opportunistic pathogen, widely exists in aquaculture water environment, which can lead to disease and even the death of shrimp in numerous reports (Nguyen et al, 2021; Santhyia et al, 2015; Zhou et al, 2012). At present, antibiotics are still the main drugs for the control and treatment of Vibrio diseases (Brumfield et al, 2021).…”

Integrated analysis of intestinal microbiota and metabolomic reveals that decapod iridescent virus 1 (DIV1) infection induces secondary bacterial infection and metabolic reprogramming in Marsupenaeus japonicus

“…Several previous studies have shown that Photobacterium can cause various diseases in fish and shrimp (Vaseeharan et al, 2007; Kanchanopas-Barnette et al, 2009; Zhang et al, 2011; Singaravel et al, 2020; Wang et al, 2020), causing huge losses in aquaculture. Vibrio harveyi, Vibrio alginolyticus and V. parahaemolyticus are three species of Vibrio , which are considered to be the main opportunistic pathogens in shrimp disease outbreaks (Zhou et al, 2012; Santhyia et al, 2015; Nguyen et al,2021). These results suggested that intestinal pathogenic bacteria were increased after DIV1 infection, which may probably because the DIV1 infection disrupted the mechanical barrier of the intestine and impaired the ability of intestine to select microorganisms.…”