Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

Abstract

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

Antimicrobial resistance in Vibrios of shrimp aquaculture: Incidence, identification schemes, drivers and mitigation measures

“…Institutional or research interventions —Surveillance for AMR in the shrimp farming environment is critical for devising strategies for mitigation and control of AMR (Bayliss et al, 2017). Research teams should bring out strategies with dose, route of application and duration of application of antibiotics in the aquaculture ponds; withdrawal period for antibiotics; more alternatives to antibiotics and make them available to the farming community; encourage farmers to use of alternate to antibiotics which are yielding promising results in the management of aquaculture ponds in controlling the count of Vibrios viz., quorum quenching bacteria against vibrios infections (Defoirdt et al, 2011; Peeralil et al, 2020), immuno‐stimulants to improve the innate immune response (Barman et al, 2013; del Carmen Flores‐Miranda et al, 2011); phytochemicals (Madagascan plant, Cinnamosma fragrans , essential oils and others) for controlling bacterial counts (Chi et al, 2017; Munaeni et al, 2020; Randrianarivelo et al, 2010; Rathnakumari et al, 2018), antimicrobial peptides against Vibrios or Vibriocins against Vibrios ( V. alginolyticus and V. parahaemolyticus ) (Cheng et al, 2019; Neha at al., 2019), lytic phage formulations for aquaculture use and finally the use of prebiotic and probiotic preparations to maintain the health status of the aquatic animals and aquaculture pond environment in entire production cycle which encompasses improving dissolved oxygen, reducing the ammonia and sulphur toxicity (Dawood et al, 2018; Duan et al, 2017; Kumar et al, 2016; Li et al, 2018; Lomelí‐Ortega et al, 2014; Nhan et al, 2010; Rao & Lalitha, 2015; Suzuki & Nam, 2018; Thornber et al, 2020; Van Doan et al, 2020; Vaseeharan & Ramasamy, 2003; Vijayan et al, 2006; Vinod et al, 2006). However, there are now emerging alternative options in reducing disease burden in shrimp aquaculture system through vaccination (Milutinovic & Kurtz, 2016) and microbiome management with whole‐genome sequencing for health status management (Zhang et al, 2014) and CRISPR‐CAS editing system which are in the nascent stage of application in the aquaculture industry (Zhu & Ge, 2018).…”

Phytochemical analysis and antibacterial activity of palm waste extract against Vibrio harveyi and Vibrio parahaemolyticus

“…Vibriosis disease can be caused by Vibrio bacteria such as V. harveyi , V. alginolyticus , V. parahaemolyticus and V. Penaeicida (Basir et al., 2023). Bacteria of the species V. harveyi (Peeralil et al., 2020) and V. parahaemolyticus are pathogenic microorganisms that often infect shrimp farming (Yu et al., 2023) and can cause death accompanied by symptomatic necrosis of the hepatopancreas of white‐footed shrimp (Saputra et al., 2023). Vibrio parahaemolyticus is widely recognized as the main causative agent of acute hepatopancreatic necrosis (AHPND) in the aquaculture of white leg shrimp ( Litopenaeus vannamei ) (Luan et al., 2023) and pathogens in the aquatic environment (Gao et al., 2023).…”

Prevalence of Bacterial Coinfections with Vibrio harveyi in the Industrialized Flow-through Aquaculture Systems in Hainan Province: A Neglected High-Risk Lethal Causative Agent to Hybrid Grouper

“…Various tissues or organs, such as the brain [ 20 ], gills [ 21 ], eyeball [ 22 ], liver [ 19 ], spleen [ 23 ], head kidney [ 24 ], intestine [ 25 , 26 ] and heart [ 27 ] have been reported to be targets of V. harveyi infection. As one of the most common pathogens worldwide, the crucial virulence genes of V. harveyi are still not systematically revealed [ 28 , 29 ] since each step of its infection is usually tightly controlled by specific virulence factors [ 30 ]. Therefore, analyzing the infection characteristics under different infection patterns, such as coinfections and monoinfection, is of great significance to uncover the key virulence genes.…”