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Flavobacterium columnare infecting Pangasianodon hypophthalmus. (A) Gross presentation of affected P. hypophthalmus during natural outbreak of F. columnare. Ruler shows cm. (B) Gross presentation of typical saddleback lesion on P. hypophthalmus observed at 84 h post-bacterial exposure with F. columnare strain FC-HN at 10 6 cfu ml −1. Patch on the dorsal area (red arrow), tail erosion (white arrow) and development of an ulcer (blue arrow) are indicated
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The bacterium Flavobacterium columnare was recovered and identified as the aetiological agent causing freshwater columnaris infection in farmed striped catfish Pangasianodon hypophthalmus (Sauvage) fingerlings that had suffered high mortality rates within commercial hatchery ponds in Vietnam. The gross clinical signs were typical of columnaris-infe...
Citations
... Flavobacterium columnare is one of the oldest known bacterial pathogens in aquaculture, having a global impact on freshwater fish farming, infecting most of the cultured species including tilapia, carp and catfish (Anderson & Conroy, 1969;Barony et al., 2015;Chockmangmeepisan et al., 2020;Dong et al., 2016;Tien et al., 2012). Recently, LaFrentz et al. (2022) reclassified Flavobacterium columnare into four distinct species: F. columnare, F. covae, F. davisii and F. oreochromis. ...
Widespread distribution of a highly pathogenic Edwardsiella ictaluri strain in farmed tilapia in northern Vietnam has recently been reported. The subsequent investigation noticed a disease outbreak occurred at five nearby tilapia farms with floating cages, in which the clinical signs of both edwardsiellosis and columnaris diseases were observed on the same infected fish and caused 65% to 85% fish mortality. Naturally diseased fish (n = 109) were sampled from the five infected farms for bacterial identification and conducting challenge tests. The two bacteria Edwardsiella ictaluri and Flavobacterium oreochromis were identified by a combination of biochemical tests, PCR and 16SrRNA sequencing methods. Experimental challenge tests on Nile tilapia resulted in the median lethal dose (LD50 ) of E. ictaluri and F. oreochromis at 70 CFU/fish by intraperitoneal (i.p.) injection and 3.6 × 106 CFU/mL by immersion, respectively. The experimentally co-infected challenged fish exposed to LD50 doses resulted in 83% ± 6% mortality, with the infected fish exhibiting clinical signs of both edwardsiellosis and columnaris diseases, mimicking the naturally diseased fish. This finding suggests that the co-infection of E. ictaluri and F. oreochromis may interact in a synergistic manner, to enhance the overall severity of the infection and elevates the need for efficient methods to control both pathogens.
... F. columnare, là tác nhân chính gây bệnh trắng đuôi, trắng da, thối đuôi trên cá nước ngọt ở nhiệt độ 20-25ºC. Đặc biệt, F. columnare gây thiệt hại rất lớn ở giai đoạn ương cá tra, hao hụt có thể lên đến 80-100% khi bội nhiễm các tác cơ hội như: nấm, vi khuẩn và ký sinh trùng, gây ảnh hưởng lớn đến sự tăng trưởng của cá và chi phí điều trị Tien et al., 2012b). Ở Mỹ, cá nheo có thể được điều trị bệnh này bằng thuốc kháng sinh và dùng vaccine sống thương mại để kiểm soát bệnh. ...
Nuôi trồng thủy sản tiếp tục là lĩnh vực sản xuất quan trọng để cung cấp nguồn thực phẩm phục vụ nhu cầu tiêu dùng trong nước và xuất khẩu, theo Chiến lược tăng trưởng ngành nuôi trồng thủy sản Việt Nam giai đoạn 2021-2030, tầm nhìn đến năm 2045, Việt Nam là quốc gia sản xuất cá tra (Pangasianodon hypophthalmus) lớn nhất trên thế giới. Do đó, việc thâm canh hoá cá tra ngày càng tăng, trong khi cơ sở hạ tầng cơ sở hạ tầng quản lý và kỹ thuật nuôi chưa theo kịp, đã dẫn đến hệ quả dịch bệnh thủy sản bùng phát ngày càng nghiêm trọng. Một số bệnh truyền nhiễm do vi khuẩn Aeromonas hydrophila, Edwardsiella ictaluri và Flavobacterium columnare có ảnh hưởng nghiêm trọng đến năng suất cá tra nuôi. Nghiên cứu này nhằm mục đích tổng hợp và đánh giá một số biện pháp để phòng ngừa và kiểm soát dịch bệnh trong nuôi cá tra thâm canh. Vaccine là chiến lược phòng chống và kiểm soát dịch bệnh hiệu quả nhất trong các chương trình quản lý dịch bệnh. Các loại vaccine cho cá bao gồm vaccine bất hoạt,...
... Vấn đề về giá cả, thị trường xuất khẩu không ổn định và sự thâm canh hóa ngày càng cao làm cho dịch bệnh trên cá tra xảy ra thường xuyên hơn là những thách thức của nghề này (Le & Cheong, 2010). Ngành công nghiệp nuôi cá tra thường xuyên bị ảnh hưởng bởi các mầm bệnh như Aeromonas hydrophila, Edwardsiella ictaluri, Flavobacterium columnare (Crumlish et al., 2002;Tien et al., 2012;Thi et al., 2015). Tình trạng lạm dụng thuốc kháng sinh trong điều trị dẫn tới sự gia tăng hiện tượng kháng thuốc trên vi khuẩn, làm giảm hiệu quả của thuốc tác động lên vi khuẩn (Preena et al., 2020) và việc tồn dư kháng sinh trong thực phẩm cũng sẽ ảnh hưởng đến sức khỏe người tiêu dùng (Reverter et al., 2020). ...
Vi khuẩn Aeromonas hydrophila là một tác nhân gây bệnh xuất huyết và dẫn đến thiệt hại nghiêm trọng về kinh tế đến nghề nuôi cá tra thâm canh. Vì vậy, việc phát triển một loại vaccine hiệu quả để bảo vệ cá tra chống lại A. hydrophila là rất cần thiết. Các chủng vi khuẩn A. hydrophila độc lực cao được sàng lọc để xác định giá trị LD50. Đánh giá khả năng bảo hộ của vaccine sau 40 ngày tiêm chủng với 4 nghiệm thức được tiêm vaccine và 1 nghiệm thức đối chứng (không tiêm vaccine). Kết quả đánh giá vaccine thông qua cảm nhiễm cho thấy vaccine đã bảo vệ cá tra với giá trị tỷ lệ bảo hộ tương đối cao lên đến 90-100% chống lại dòng vi khuẩn A. hydrophila AH03. Kết quả phân tích ngưng kết miễn dịch cho thấy mức kháng thể đặc hiệu tăng lên ở các nghiệm thức tiêm vaccine sau 10 ngày (3,5-7) và giảm nhẹ (5-8) sau 40 ngày tiêm vaccine. Tóm lại, vaccine A. hydrophila bất hoạt là một sản phẩm đầy hứa hẹn cung cấp khả năng bảo hộ cao cho cá tra nuôi.
... The first isolates of F. columnare were isolated from aquarium fish such as Koi (Cyprinus carpio), black molly (Poecilia sphenops) and platy (Xiphophorus maculatus) by Decostere et al., (1998). The emergence of columnaris disease on striped catfish currently has leaded high economic loss due to high mortality within commercial hatchery ponds (Tien et al., 2012). The adhesion of bacteria to tissues has been considered as a crucial step in pathogenesis of many infections in animals and human beings (Magarinos et al., 1996). ...
... Then traditional plate count method was performed to identify cfu/mL. Designed dose for immersion challenge was 6.93x10 6 cfu/mL according to the median lethal concentration (LC 50 ) tested in striped catfish fingerlings (3-6g) previously (Tien et al., 2012). Fishes were divided into 7 groups: 0, 3, 6, 9, 12, 15 ppt (by gradually increased 3 ppt per day) and the control group. ...
This research was conducted to investigate the biofilm formation ability at various salt concentrations and temperatures of Flavobacterium columnare isolated from striped catfish (Pangasianodon hypophthalmus) at Can Tho University. Microtiter plate assay and the in vivo challenge were used to test the virulence of this strain of F. columnare for 10 days by immersion method at different salt concentrations (0, 3, 6, 9, 12 and 15 ppt). Results showed that biofilm formation of F.columnare was inhibited at 3 and 6 ppt and stronger reductions were recorded at 9, 12 and 15 ppt. In the same trend, the higher temperature the lower biofilm formation, the highest biofilm formation was at 25°C treatment, then it was reduced at 28 and 31°C and at 35°C the formed biofilm was greatly reduced. Interestingly, there were no statistically significant differences between 28 and 31°C (P>0.05). The virulent study found that 100% fish died after 1 day post challenge at 0 ppt. There were 10% and 25% of fish died at 3 and 6 ppt respectively. No dead fish was found at 9 and 12 ppt. In conclusion, biofilm formation was inhibited at 3 ppt, was almost controlled at 9, 12 and 15 ppt and was also mostly reduced at 31°C at least in the in-vitro study. Furthermore, the virulence of this bacterial strain was controlled 90% at 3 ppt and completely controlled (100%) at 9, 12 and 15 ppt.
... MAS is caused by Aeromonas hydrophila and related motile aeromonads (Plumb and Hanson 2011). Tail rot, caused by Flavobacterium columnare, is another common highly pathogenic bacterial disease in farmed striped catfish in Vietnam (Tien et al. 2012). Parasitic disease is a general expression for a group of diseases that can be caused by a variety of external and internal parasites, and therefore varies considerably in impact and clinical signs. ...
This study describes the prevalence of common diseases and pathogens of Pangasianodon hypophthalmus in nursing farms in the Mekong delta, Vietnam, and identifies the preventive husbandry measures in use by these farms and their association with diseases. In a first study, farmers of 63 randomly selected nursing farms in An Giang, Can Tho, and Dong Thap provinces were interviewed using semi-structured questionnaires. Questions included topics on disease occurrence and application of husbandry measures in their last crop. The results showed that prevalence of bacillary necrosis of pangasius (BNP) was 75%, motile Aeromonas septicemia (MAS) 60%, parasitic disease 48%, saprolegniasis 19%, pale gill and liver syndrome 17%, tail rot 14%, and swollen swim bladder disease 3%. Eighty-eight percent of farmers had more than one of these diseases in their last crop. The duration of these crops are on average 2 months. Delaying the onset of feed training was significantly preventive for MAS (OR = 0.85, 0.75–0.95 95% CI) and BNP (OR = 0.88, 0.78–0.97), using iodine to disinfect water for BNP (OR = 0.23, 0.05–0.95), draining the pond sludge for parasitic disease (OR = 0.32, 0.10–0.97) and reducing time between filling the pond with water and stocking of fish for parasitic disease (OR of increasing time was 2.49, 1.13–6.40). Of all farmers interviewed, 43% used antibiotics preventively in fish food, but this practice was not significantly associated with lower disease prevalence. In a second study, fish from 48 randomly selected nursing ponds were sampled. Samples were randomly split to diagnose parasites (n = 443), common bacteria (n = 48 pools), or common fungi (n = 371). Prevalences of some pathogens were high, i.e. the parasite Trichodina, 48%, the bacteria Aeromonas hydrophila, causative for MAS, 23%, the bacteria Edwardsiella ictaluri, causative for BNP, 40%, the fungi Fusarium spp., causative for swollen swim bladder disease, 9.7%, and the fungi Aspergillus spp. 9.4%. The high prevalence of some of these diseases and pathogens is concerning, and shows that current preventive and mitigation measures need to be improved. The high number of crops with multiple diseases may indicate a reduced general resilience of the fish, which indicates that mitigation strategies would benefit from a comprehensive approach, instead of focused on single diseases or pathogens. Current preventive husbandry practices needs optimizing, but can play an important role in future mitigation strategies towards improved sustainability of striped catfish nursing farms.
... The F. columnare bacterium was isolated and identified as an etiological factor of infectious disease in Platydoras costatus. Clinical signs were typical of fish columnaris, and microscopic studies revealed numerous Gram-negative filamentous bacteria on the skin, muscle, and gill tissue of the affected fish (Tien et al., 2012). ...
Bacterial preparations contribute to the digestion of mineral nutrition, have antifungicidal activity, increase the grain productivity and biomass of cultivated crops. We studied the influence of microbiological preparations developed on the basis of microorganisms Bacillus subtilis and Lactobacillus buchneri on the growth processes, photosynthetic parameters and grain productivity of barley (Hordeum vulgare L.) of Sonet variety. The experiments were performed in 2019 in the North-West of the Russian Federation. The biological preparations were introduced by soaking seeds and treatment of the plants in the phase of third leaf with solutions of the preparations in the concentration of 1 mL/L. The laboratory surveys revealed the positive effect of the biological preparations on germination rate and energy of germination of seeds. Field trials were conducted on micro plots in six replications. During field experiments, we determined that introduction of biological preparations led to significant increase in the leaf area in the experimental plants (to 64.5%), increase in average daily growth gains (to 82.9%) and accumulation of biomass (to 73.1%). Somewhat higher efficiency was exerted by the biological preparation developed on the basis of a strain of L. buchneri. Perhaps, such effect takes place due to higher activity of pigment units of phytohormones of the auxin group. In our opinion, biological preparations accelerate the completion of the ontogenesis phases, thus the plants more rapidly achieve their genetically programmed sizes and transform to the stage of ear-formation. The studied biological preparations increased the coefficient of agricultural use of plants, and grain productivity of barley by up to 15.8%, and nutritional value remained. Microbial preparations on the basis of B. subtilis and L. buchneri exhibited efficiency, and their trials shall be continued on other crops on industrial scales.
... The F. columnare bacterium was isolated and identified as an etiological factor of infectious disease in Platydoras costatus. Clinical signs were typical of fish columnaris, and microscopic studies revealed numerous Gram-negative filamentous bacteria on the skin, muscle, and gill tissue of the affected fish (Tien et al., 2012). ...
The work is devoted to the calculation, comparison of indicators and the development of a method for regulating the intensity of lipid peroxidation processes (LPP) of strains of basidiomycetes. The purpose of the investigation is to study the effect of phenolic type chemicals and hydrogen peroxide on the lipid peroxidation of certain strains of basidiomycetes under laboratory cultivation. Cultivation of strains of basidiomycetes was carried out by periodic surface method on glucose-peptone medium (GPM) in flasks. The influence of sodium lignosulfonate, tannin, gallic acid and hydrogen peroxide at 0.1% concentration at 24 and 48 hours of exposure on the intensity of lipid peroxidation processes of the strains Pleurotus eryngii P-er, Fistulina hepatica Fh-08 and Agrocybe cylindracea 960, fungi of the phylum Basidiomycota, orderAgaricales has been investigated. It was established that the used phenolic-type chemical compounds that are part of the lignocellulose complex of wood or are the products of its decomposition to a certain extent affect the lipid peroxidation processes of mycelial cell lipids in the studied cultures of basidium fungi. The individual reaction of LPP of cultures to the applied substance and the time of its exposure are determined. The highest degree of LPP induction was recorded upon addition of tannin – by 161%, after 48 hours of exposure in the mycelium of strain Fh-08; sodium lignosulfonate – by 192%, after 48 hours in the mycelium of strain P-er; gallic acid – by 182%, after 24 hours, in the mycelium of strain P-er; hydrogen peroxide – by 257%, after 24 hours, in the CR of strain 960. The biotechnological significance of this is the possibility of regulation (induction or repression) of LPP of producer strains. From a biomedical point of view, the possibility of changing the activity of lipid peroxidation processes of mycelium and culture fluid makes it possible to obtain and use more effective functional products of fungal origin.
... Several cultured fish species e.g. channel catfish, Ictalurus punctatus (Shoemaker et al., 2008), striped catfish, Pangasianodon hypophthalmus (Tien et al., 2012;Dong et al., 2015c), rainbow trout, Oncorhynchus mykiss (Lafrentz et al., 2012), hybrid red tilapia, Oreochromis sp. (Dong et al., 2015a) and Nile tilapia, Oreochromis niloticus (Dong et al., 2015b), are known to be susceptible to columnaris disease. ...
Flavobacterium columnare is the causative organism of columnaris disease in freshwater fish, which may exhibit differences in pathogenicity. The virulence properties and the pathogenicity of F. columnare in juvenile hybrid red tilapia were investigated using a collection of F. columnare isolates recovered from diseased fish. Ten isolates were selected to perform immersion challenge assay in juvenile tilapia. The pathogenicity was highly diverse. Subsequently, three bacterial isolates exhibited different pathogenicity levels, consisting of high, moderate and low virulence (100%, 80% and 0% mortality respectively) and were subjected to virulence properties evaluation e.g. the median lethal dose (LD 50), bacterial adhesion, capsular production and biofilm formation. Interestingly, the adhesion ability to the gill surface, biofilm formation and the production of capsular polysaccharide are significantly associated with the highly pathogenic traits of F. columnare. These findings suggest that efficient columnaris disease control in farmed fish should target these pivotal virulence properties.
... Columnaris, also recognized as saddleback disease, is a notorious infectious disease in freshwater aquaculture species due to its high severity which can cause acute mortality up to 100% within 24 h (Declercq et al., 2013). To this day, F. columnare has been distributed worldwide and the outbreaks of acute mortality associated with columnaris have also been reported in several cold and warm aquaculture freshwater fish species, such as channel catfish (Ictalurus punctatus), red tilapia (Oreochromis sp.), Nile tilapia (Oreochromis niloticus), common carp, (Cyprinus carpio), striped catfish (Pangasianodon hypophthalmus) and rainbow trout (Oncorhynchus mykiss), leading to tremendous losses in the aquaculture industry annually (Dong et al., 2015a;LaFrentz et al., 2012;Rahman et al., 2010;Shoemaker et al., 2008;Tien et al., 2012). ...
Flavobacterium columnare is one of the deadliest fish pathogens causing devastating mortality in various freshwater fish species globally. To gain an insight into bacterial genomic contents and structures, comparative genome analyses were performed using the reference and newly sequenced genomes of F. columnare including genomovar I, II and I/II strains isolated from Thailand, Europe and the USA. Bacterial genomes varied in size from 3.09 to 3.39 Mb (2714 to 3101 CDSs). The pan-genome analysis revealed open pan-genome nature of F. columnare strains, which possessed at least 4953 genes and tended to increase progressively with the addition of a new genome. Genomic islands (GIs) present in bacterial genomes were diverse, in which 65% (39 out of 60) of possible GIs were strain-specific. A CRISPR/cas investigation indicated at least two different CRISPR systems with varied spacer profiles. On the other hand, putative virulence genes, including those related to gliding motility, type IX secretion system (T9SS), outer membrane proteins (Omp), were equally distributed among F. columnare strains. The MLSA scheme categorized bacterial strains into nine different sequence types (ST 9–17). Phylogenetic analyses based on either 16S rRNA, MLSA and concatenated SNPs of core genome revealed the diversity of F. columnare strains. DNA homology analysis indicated that the estimated digital DNA-DNA hybridization (dDDH) between strains of genomovar I and II can be as low as 42.6%, while the three uniquely tilapia-originated strains from Thailand (1214, NK01 and 1215) were clearly dissimilar to other F. columnare strains as the dDDH values were only 27.7–30.4%. Collectively, this extensive diversity among bacterial strains suggested that species designation of F. columnare would potentially require re-emendation.
... A list of 37 susceptible fish species was suggested by Anderson & Conroy (1969), and this number has increased in recent years with Nile tilapia Oreochromis niloticus (L.) (Figueiredo et al. 2005;Eissa, Zaki & Aziz 2010), red tilapia Oreochromis sp. (Dong et al. 2014), Indian carp Catla catla (Hamilton) (Verma & Rathore 2013), striped catfish Pangasianodon hypophthalmus (Sauvage) (Tien et al. 2012) and rainbow trout Oncorhynchus mykiss (Walbaum) (LaFrentz et al. 2012) reported as susceptible. Naturally infected fish usually show lesions on the external body surface and gills such as skin damage, fin rot, 'saddle back' lesion or gill necrosis (Bernardet & Bowman 2006;Declercq et al. 2013). ...
