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natural coinfection by streptococcus agalactiae and francisella noatunensis subsp. orientalis in farmed nile tilapia (oreochromis niloticus l.).streptococcus agalactiae and francisella noatunensis subsp. orientalis (fno) are important pathogens for farm-raised tilapia worldwide. there are no reports of coinfection caused by s. agalactiae and fno in fish. this study aimed to determine the aetiology of atypical mortalities in a cage farm of nile tilapia and to characterize the genetic diversity of the isolates. fifty-two fish were sampled and subjected to parasitological and bacteriological examination. the s. agalactiae and fno isolates ...201727144661
characterization and vaccine potential of membrane vesicles produced by francisella noatunensis sup. orientalis in an adult zebrafish model.vaccine development against extracellular bacteria has been important for the sustainability of the aquaculture industry. in contrast, infections with intracellular pathogens remain largely an unresolved problem. francisella noatunensis subspecies orientalis (fno) are gram-negative, facultative intracellular bacteria that cause the disease francisellosis in fish. francisellosis is commonly characterized as a chronic granulomatous disease with high morbidity and can result in high mortality depen ...201728331079
draft genome sequence of francisella noatunensis subsp. orientalis stir-gus-f2f7, a highly virulent strain recovered from diseased red nile tilapia farmed in europe.a highly virulent strain of francisella noatunensis subsp. orientalis, stir-gus-f2f7, was isolated from moribund red nile tilapia (oreochromis niloticus) farmed in europe. in this communication, the complete genome sequencing of this bacterium is reported.201728302784
interaction of francisella noatunensis subsp. orientalis with oreochromis mossambicus bulbus arteriosus cell line.francisella noatunensis subsp. orientalis (fno) (syn. f. asiatica) is an emergent warmwater fish pathogen and the causative agent of piscine francisellosis. although fno causes septicemia and can live extracellularly in infected tilapia (oreochromis spp.), the early interaction of fno with vasculature endothelium is unknown. in the present study, we examined the interaction of wild-type fno (wt) and two fno knockout [intracellular growth loci c (δiglc) and pathogenicity determinant protein a (δp ...201728286149
in vitro assessment of the antimicrobial activity of silver and zinc oxide nanoparticles against fish pathogens.antibiotic resistance is a global issue that threatens public health. the excessive use of antibiotics contributes to this problem as the genes of antibiotic resistance can be transferred between the bacteria in humans, animals and aquatic organisms. metallic nanoparticles could serve as future substitutes for some conventional antibiotics because of their antimicrobial activity. the aim of this study was to evaluate the antimicrobial effects of silver and zinc oxide nanoparticles against major ...201728732514
immunomodulatory properties of concholepas concholepas hemocyanin against francisellosis in a zebrafish model.the development of vaccines for aquaculture has been an important milestone in providing a continuous and sustainable production. most of the vaccines currently on the market for aquaculture include oil as adjuvant. nevertheless, several studies reported an occurrence of side effects after their use in farmed fish. as a result, there is a need for new and improved adjuvants that can stimulate the immune system while causing as few side-effects as possible. hemocyanins are versatile macromolecule ...201728634011
molecular detection of francisella noatunensis subsp. orientalis in cultured nile tilapia (oreochromis niloticus l.) in three brazilian states. 201728449216
a polyphasic approach for phenotypic and genetic characterization of the fastidious aquatic pathogen francisella noatunensis subsp. orientalis.francisella noatunensis subsp. orientalis (fno) is the causative agent of piscine francisellosis, an emerging infectious disease in asia and latin america. in this study two outbreaks of francisellosis were diagnosed in the uk on the basis of histopathology, electron microscopy, pcr, bacterial isolation and fulfillment of koch's postulates. furthermore, a phenotypic fingerprint based on biochemical analyses, metabolic activity, chemotaxonomic composition, and antimicrobial assays was generated f ...201729312155
sensitivity and specificity of real-time pcr and bacteriological culture for francisellosis in farm-raised nile tilapia (oreochromis niloticus l.).despite the worldwide occurrence of francisella noatunensis subsp. orientalis (fno) infection in farmed tilapia, sensitivity and specificity estimates of commonly used diagnostic tests have not been reported. this study aimed to estimate the sensitivity and specificity of bacteriological culture and qpcr to detect fno infection. we tested 559 fish, sampled from four farms with different epidemiological scenarios: (i) healthy fish in a hatchery free of fno; (ii) targeted sampling of diseased fish ...201627670740
susceptibility of common carp and sunfish to a strain of francisella noatunensis subsp. orientalis in a challenge experiment.francisellosis, an emerging disease in many fish species, can cause high mortality in affected populations. here we investigated the susceptibility of common carp cyprinus carpio and sunfish lepomis gibbosus to francisella noatunensis subsp. orientalis (fno), and possible transmission of the bacteria between the 2 fish species. in a challenge experiment, 3 groups of each species were injected intraperitoneally (ip) with 3 different doses of an fno strain no. 9449 of the norwegian veterinary inst ...201627667813
first identification of francisella noatunensis subsp. orientalis causing mortality in mexican tilapia oreochromis spp.francisellosis, an emerging disease in tilapia oreochromis spp., is caused by the facultative, intracellular bacterium francisella noatunensis subsp. orientalis, which is present in various countries where tilapia farming is commercially important. we confirmed the presence of francisellosis in mexican tilapia cultures in association with an outbreak during the second semester of 2012. broodstock fish presented a mortality rate of approximately 40%, and disease was characterized by histologicall ...201627503916
duplex pcr assay and in situ hybridization for detection of francisella spp. and francisella noatunensis subsp. orientalis in red tilapia.conventional isolation and identification based on phenotypic characteristics is challenging with the highly fastidious, intracellular bacterium francisella noatunensis subsp. orientalis (fno). here, we developed a duplex pcr method for simultaneous detection of the francisella genus and fno in one pcr reaction and an in situ hybridization method for paraffin section based diagnosis of fno. the pcr results showed genus- and species-specific bands (1140 and 203 bp) from fno but only one genus-spe ...201627304869
complete genome sequences of francisella noatunensis subsp. orientalis strains fno12, fno24 and fno190: a fish pathogen with genomic clonal behavior.the genus francisella is composed of gram-negative, pleomorphic, strictly aerobic and non-motile bacteria, which are capable of infecting a variety of terrestrial and aquatic animals, among which francisella noatunensis subsp. orientalis stands out as the causative agent of pyogranulomatous and granulomatous infections in fish. accordingly, f. noatunensis subsp. orientalis is responsible for high mortality rates in freshwater fish, especially nile tilapia. in the current study, we present the ge ...201627073591
dynamics of piscine francisellosis differs amongst tilapia species (oreochromis spp.) in a controlled challenge with francisella noatunensis subsp. orientalis.a 25-week immersion challenge was conducted exposing oreochromis mossambicus, oreochromis aureus and oreochromis urolepis hornorum to francisella noatunensis subsp. orientalis (fno). two populations were compared for each fish species; 'resident fish' were defined as fish maintained in tanks since week 0 of challenge, whereas 'naïve fish' were defined as fish added to tanks once temperature in water reached <26 °c at 21 weeks post-challenge. fno genome equivalents (ges) in water were similar in ...201626916547
whole-genome sequence of francisella noatunensis subsp. orientalis strain fno01 isolated from diseased nile tilapia in brazil.this paper describes the complete genome sequence of francisella noatunensis subsp. orientalis strain fno01, which was isolated during the first outbreak of francisellosis in cultured nile tilapia in brazil. the genome is composed of a circular chromosome with 1,859,830 bp and a g+c content of ~32%.201626798105
biofilm formation of francisella noatunensis subsp. orientalis.francisella noatunensis subsp. orientalis (fno) is an emergent fish pathogen in both marine and fresh water environments. the bacterium is suspected to persist in the environment even without the presence of a suitable fish host. in the present study, the influence of different abiotic factors such as salinity and temperature were used to study the biofilm formation of different isolates of fno including intracellular growth loci c (iglc) and pathogenicity determinant protein a (pdpa) knockout s ...201526507830
effect of size and temperature at vaccination on immunization and protection conferred by a live attenuated francisella noatunensis immersion vaccine in red hybrid tilapia.francisella noatunensis subsp. orientalis (fno) is a pleomorphic, facultative intracellular, gram-negative, emerging bacterial pathogen of marine and fresh water fish with worldwide distribution. in this study, the efficacy of an attenuated fno intracellular growth locus c (iglc) mutant was evaluated for use as a live immersion vaccine, when administered to hybrid tilapia at two different stages of growth (5 g fry and 10 g fingerlings) and at two temperatures (25 °c and 30 °c). to determine vacc ...201425462454
outbreaks and genetic diversity of francisella noatunensis subsp orientalis isolated from farm-raised nile tilapia (oreochromis niloticus) in brazil.francisella noatunensis subsp orientalis (fno) is an emerging pathogen of warm water tilapia in a number of different countries. the disease caused by this bacterium in fish is characterized by a systemic granulomatous infection that causes high mortality rates during outbreaks. fno has been previously described in asia, europe, and central and north america. its occurrence in south america has never been described. since 2012, outbreaks of a granulomatous disease have been recorded in cage farm ...201425117328
prevalence of francisella noatunensis subsp. orientalis in cultured tilapia on the island of oahu, hawaii.francisellosis is an emergent disease in cultured and wild aquatic animals. the causative agent, francisella noatunensis subsp. orientalis (fno), is a gram-negative bacterium recognized as one of the most virulent pathogens of warmwater fish. the main objective of this project was to investigate the prevalence of fno in cultured tilapia (specifically, mozambique tilapia oreochromis mossambicus, koilapia [also known as wami tilapia] o. hornorum, blue tilapia o. aureus, and nile tilapia o. nilotic ...201323639074
francisella guangzhouensis sp. nov., isolated from air-conditioning systems.four strains (08hl01032(t), 09hg994, 10hp82-6 and 10hl1960) were isolated from water of air-conditioning systems of various cooling towers in guangzhou city, china. cells were gram-stain-negative coccobacilli without flagella, catalase-positive and oxidase-negative, showing no reduction of nitrate, no hydrolysis of urea and no production of h2s. growth was characteristically enhanced in the presence of l-cysteine, which was consistent with the properties of members of the genus francisella. the ...201323606480
francisella noatunensis subsp. orientalis pathogenesis analyzed by experimental immersion challenge in nile tilapia, oreochromis niloticus (l.).francisella noatunensis subsp. orientalis (fno) (syn. f. asiatica) is an emergent warmwater fish pathogen and the causative agent of francisellosis in tilapia (oreochromis sp). to study the pathogenesis of this bacterium, tilapia fingerlings were experimentally infected by immersion challenge with wild type (wt) fno and the distribution of bacteria to multiple organs, as well as associated lesion development, investigated after 3, 24, 48, 96, and 192h by real-time pcr and histopathological exami ...201323415477
francisella noatunensis subsp. orientalis infection in indo-pacific reef fish entering the united states through the ornamental fish trade. 201323305537
efficacy of florfenicol for control of mortality associated with francisella noatunensis subsp. orientalis in nile tilapia, oreochromis niloticus (l.).francisella noatunensis subsp. orientalis (fno) (syn. f. asiatica) is an emergent gram-negative facultative intracellular bacterium. although it is considered one of the most pathogenic bacteria in fish, there are no commercially available treatments or vaccines. the objective of this project was to determine the most efficacious concentration of florfenicol (ffc) [10, 15 or 20 mg ffc kg(-1) body weight (bw) per days for 10 days] administered in feed to control experimentally induced infections ...201323134104
molecular and immunohistochemical diagnosis of francisella noatunensis subsp. orientalis from formalin-fixed, paraffin-embedded tissues.members of the genus francisella (viz., f. noatunensis subsp. orientalis [fno] and f. noatunensis subsp. noatunensis) have been described as causative agents of chronic granulomatous and pyogranulomatous lesions in wild and cultured fish species. in the present study, 68 archived formalin-fixed, paraffin-embedded (ffpe) tissues from several fish species, collected at different geographical locations from 2000 to 2011, were analyzed using a real-time polymerase chain reaction assay for the detect ...201222786972
whole genome sequencing of the fish pathogen francisella noatunensis subsp. orientalis toba04 gives novel insights into francisella evolution and pathogenecity.francisella is a genus of gram-negative bacterium highly virulent in fishes and human where f. tularensis is causing the serious disease tularaemia in human. recently francisella species have been reported to cause mortality in aquaculture species like atlantic cod and tilapia. we have completed the sequencing and draft assembly of the francisella noatunensis subsp. orientalistoba04 strain isolated from farmed tilapia. compared to other available francisella genomes, it is most similar to the ge ...201223131096
effects of temperature and salt concentration on francisella noatunensis subsp. orientalis infections in nile tilapia oreochromis niloticus.little is known about the environmental conditions that allow francisella noatunensis subsp. orientalis, a worldwide emergent bacterial fish pathogen, to colonize and infect wild and cultured fish. we evaluated the effect of temperature and salinity on the infectivity of f. noatunensis subsp. orientalis in nile tilapia oreochromis niloticus (l). immersion challenges of tilapia with f. noatunensis subsp. orientalis at water temperatures of 25 and 30°c in both sea and fresh water were conducted fo ...201223324418
Genetic analysis and antimicrobial susceptibility of Francisella noatunensis subsp. orientalis (syn. F. asiatica) isolates from fish.Francisella noatunensis subsp. orientalis (syn. F. asiatica) (Fno) is an emergent fish pathogen that causes acute to chronic disease in a wide variety of freshwater, brackish and marine fish. Due to the emergent nature of this bacterium, established protocols to measure antimicrobial susceptibility are lacking. In this project we compare three different methods to examine the antimicrobial susceptibility (Etest, broth microdilution and disk diffusion) of 10 different isolates of Fno from two dif ...201221868177
francisella asiatica as the causative agent of piscine francisellosis in cultured tilapia (oreochromis sp.) in the united states.francisella asiatica is a gram-negative, pleomorphic, facultative intracellular, bacterial pathogen that causes acute to chronic disease in a wide variety of warm-water cultured and wild fish species. outbreaks of francisellosis in warm water fish have been documented in taiwan, japan, united kingdom, hawaii, and latin america (including costa rica) but the organism has only been reported from the united states on one occasion from hybrid striped bass in california. in 2010, the bacterium was de ...201121908332
culturability and persistence of francisella noatunensis subsp. orientalis (syn. francisella asiatica) in sea- and freshwater microcosms.francisella noatunensis subsp. orientalis (syn. francisella asiatica), the causative agent of franciselliosis in warm-water fish, is a gram-negative facultative intracellular bacterium. although it has been characterized as one of the most pathogenic bacteria in fish, the water conditions that allow for its survival and infectious capacities outside the fish host are not known. data obtained in this project indicate that both temperature and salinity are important factors in the culturability an ...201121881943
attenuated francisella asiatica iglc mutant induces protective immunity to francisellosis in tilapia.francisella asiatica is a gram-negative, facultative intracellular bacteria that causes fish francisellosis. fish francisellosis is a severe sub-acute to chronic granulomatous disease with high mortalities and high infectivity rates in cultured and wild fish. to date, there is no approved vaccine for this widespread emergent disease. the goal of this study was to characterize the efficacy of a defined f. asiatica mutant (δiglc) as a live attenuated vaccine against subsequent immersion challenge ...201120600508
in vitro and in vivo efficacy of florfenicol for treatment of francisella asiatica infection in tilapia.francisella asiatica is a recently described, gram-negative, facultative intracellular fish pathogen, known to be the causative agent of francisellosis in warm-water fish. francisellosis outbreaks have increased in frequency among commercial aquaculture operations and have caused severe economic losses in every case reported. the lack of effective treatments for piscine francisellosis led us to investigate the potential efficacy of florfenicol for inhibition of f. asiatica in vitro and as an ora ...201020713674
interaction of francisella asiatica with tilapia (oreochromis niloticus) innate immunity.members of the genus francisella are facultative intracellular bacteria that cause important diseases in a wide variety of animals worldwide, including humans and fish. several genes that are important for intramacrophage survival have been identified, including the iglc gene, which is found in the iglabcd operon in the francisella sp. pathogenicity island (fpi). in the present study, we examined the interaction of wild-type francisella asiatica and a delta iglc mutant strain with fish serum and ...201020160018
development of a real-time pcr assay for identification and quantification of the fish pathogen francisella noatunensis subsp. orientalis.members of the genus francisella are small gram-negative facultative intracellular bacteria that cause francisellosis in a wide variety of fish species worldwide. f. noatunensis subsp. orientalis has been recently described as a warm-water pathogen of tilapia oreochromis spp. in this study, a quantitative real-time polymerase chain reaction (qpcr) taqman probe assay was developed to rapidly and accurately detect and quantify f. noatunensis subsp. orientalis from fish tissue. the target region of ...201020481087
elevation of francisella philomiragia subsp. noatunensis mikalsen et al. (2007) to francisella noatunensis comb. nov. [syn. francisella piscicida ottem et al. (2008) syn. nov.] and characterization of francisella noatunensis subsp. orientalis subsp. nov., two important fish pathogens.this study was conducted to clarify the taxonomic status of francisella sp. strain ehime-1, a fish pathogen, in relation to the fish pathogens f. piscicida and f. philomiragia subsp. noatunensis and to f. philomiragia subsp. philomiragia.200919187160
francisella asiatica sp. nov. isolated from farmed tilapia (oreochromis sp.) and elevation of francisella philomiragia subsp. noatunensis to species rank as francisella noatunensis comb. nov., sp. nov.bacterial isolates from diseased farmed tilapia (oreochromis sp.) from costa rica (pq 1104), atlantic salmon (salmo salar) from chile (pq 1106) and three-line grunt (parapristipoma trilineatum) from japan (ehime-1) were characterized by phenotypic and molecular taxonomic methods. these isolates were gram-negative, oxidase negative, non-motile, strictly aerobic cocco-bacilli, produced h2s from cysteine supplemented media, which is phenotypically consistent with the genus francisella. comparison o ...200919783606
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