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1.
Mycobacterium spp. isolated from food and ornamental fish in Thailand (TB1, TB40, TB267 and TB268), and the type strains Mycobacterium marinum (NCIMB 1298), M. fortuitum (NCIMB 1294) and M. chelonae (NCIMB 1474) were cultured in Long's medium, Eagle's minimum essential medium, Sauton's medium and modified Sauton's medium. The latter enabled excellent growth and production of extracellular products (ECP) from TB 40, TB267, TB268 and M. marinum NCIMB 1298 in particular, whereas growth and production of ECP for all strains was limited in Long's medium. SDS-PAGE protein profiles of ECPs from 14-day culture supernatants showed major bands at 65 and <14 kDa. After 2 days culture at the higher temperature of 37°C (heat shock), the production of ECP from all mycobacteria strains except M. marinum averaged approximately four- to 10-fold higher than from strains cultured for 14 days at 28°C. Enzyme testing for the type strains indicated only mucinase activity for M. marinum, while lipase and RNase activities were detected for M. chelonae and M. fortuitum . Protease and DNase activities could not be detected for any of the Mycobacterium spp. tested. The medium lethal dose (LD50) of ECP to rainbow trout and Nile tilapia was greater than 400 μg protein fish–1.  相似文献   

2.
Mycobacterium marinum is the causative agent of mycobacteriosis in wild and cultured fish and of atypical infection in humans. For the diagnosis of M. marinum , cultural and traditional polymerase chain reaction (PCR) methods are currently used. However, these protocols, although able to discriminate within Mycobacterium spp., have proved to be time-consuming or difficult to carry out. For this reason, the aim of this study was to obtain a rapid and specific diagnostic tool to quantify fish Mycobacterium spp. or to discriminate M. marinum from other mycobacteria. A primary PCR amplification with SYBR Green had a detection limit (dl) of 102 Mycobacterium DNA copies with a log-linear quantification range up to 104 ( R 2 = 0.99). The second PCR using FRET probes, flanking a region containing species specific nucleotide variations, was designed and validated with synthetic erp gene fragments corresponding to different mycobacterial species, different whole mycobacteria suspensions, experimentally infected fish tissues, tissues from experimentally infected fish, and samples of cultured fish. The results show that the FRET probes demonstrate a high specificity as the melting curve analysis allowed efficient discrimination of M. marinum from Mycobacterium chelonae , Mycobacterium fortuitum , Mycobacterium pseudoshottsii , Mycobacterium shottsii and Mycobacterium ulcerans . The kidney is the organ with the strongest detection signal and using fish tissues the method has a mean sensitivity of 50 DNA copies/PCR.  相似文献   

3.
A variety of methods have been used to identify Mycobacterium spp. isolated from snakehead and Siamese fighting fish, including biochemistry, mycolic acid profiles and antibody-based methods. However, these methods are unable to differentiate between different species of Mycobacterium . Polymerase chain reaction (PCR) followed by reverse cross blot hybridization (RCBH) was adapted in this study to speciate aquatic mycobacteria. The method was highly specific for Mycobacterium spp. and identified the bacteria to species level with a detection limit of 100 fg DNA, equivalent to 20 mycobacteria. Twenty-nine isolates previously collected and cultured from Siamese fighting fish (10 isolates) and snakehead (19 isolates) during outbreaks of mycobacteriosis were analysed using PCR–RCBH. Six of the Siamese fighting fish isolates and nine of the snakehead isolates were identified as Mycobacterium fortuitum , while the remainder were classified as M. marinum . Notably, two isolates recovered from snakehead and Siamese fighting fish, previously identified as M. poriferae and M. piscicida , respectively, were confirmed to be M. fortuitum .  相似文献   

4.
Some mycobacterial species (particularly Mycobacterium marinum) found in aquarium environments may cause chronic diseases in fish and cutaneous infections in humans, the so-called 'fish tank granuloma'. The presence and distribution of mycobacterial species in clinically healthy aquarium fish and their environment has not been adequately explored. The present study analysed the occurrence of mycobacteria in a decorative aquarium (Brno, South Moravia) and in five aquaria of a professional fish breeder (Bohumin, North Moravia). After Ziehl-Neelsen staining, acid-fast rods (AFR) were observed in six (14.3%) and mycobacteria were detected by culture in 18 (42.9%) of 42 tissue samples from 19 fish. Sixty-five samples of the aqueous environment from all six aquaria were examined; AFR were found in 16 (24.6%) and mycobacteria were detected by culture in 49 (75.4%) samples. Forty-one (70.7%) of 58 selected mycobacterial isolates were identified biochemically as follows: M. fortuitum, M. flavescens, M. chelonae, M. gordonae, M. terrae, M. triviale, M. diernhoferi, M. celatum, M. kansasii and M. intracellulare. The clinically important species for humans and fish, M. marinum, was not detected. Mycobacterium kansasii was isolated from one sample of the aquarium environment from North Moravia, which is a region of the Czech Republic with endemic incidence of M. kansasii in water. The incidence of other conditionally pathogenic mycobacterial species in healthy fish and in all investigated constituents of the aquarium environment including snails and crustaceans used for fish feeding, was quite high. Accordingly, mycobacterial species from aquarium environments may serve as a possible source of infection for both aquarium fish and immunodeficient fish handlers.  相似文献   

5.
A survey of the occurrence of mycobacteria was conducted from 717 freshwater fish (25 species) in two water reservoirs, five ponds and two farms in the Czech Republic. A total of 2182 tissue samples from these fish were examined using the conventional culture method. Thirteen mycobacterial isolates were obtained from 12 (1.7%) fish belonging to nine species. Isolates were identified using sequence analysis of the 16SrRNA gene as: Mycobacterium algericum, M. fortuitum, M. gordonae, M. insubricum, M. kumamotonense, M. nonchromogenicum, two isolates of M. peregrinum, M. terrae and M. triplex. Mycobacteria were isolated more frequently from fish skin and gills than from internal organs or muscles.  相似文献   

6.
Mycobacteria are significant pathogens of laboratory zebrafish, Danio rerio (Hamilton). Stress is often implicated in clinical disease and morbidity associated with mycobacterial infections but has yet to be examined with zebrafish. The aim of this study was to examine the effects of husbandry stressors on zebrafish infected with mycobacteria. Adult zebrafish were exposed to Mycobacterium marinum or Mycobacterium chelonae , two species that have been associated with disease in zebrafish. Infected fish and controls were then subjected to chronic crowding and handling stressors and examined over an 8-week period. Whole-body cortisol was significantly elevated in stressed fish compared to non-stressed fish. Fish infected with M. marinum ATCC 927 and subjected to husbandry stressors had 14% cumulative mortality while no mortality occurred among infected fish not subjected to husbandry stressors. Stressed fish, infected with M. chelonae H1E2 from zebrafish, were 15-fold more likely to be infected than non-stressed fish at week 8 post-injection. Sub-acute, diffuse infections were more common among stressed fish infected with M. marinum or M. chelonae than non-stressed fish. This is the first study to demonstrate an effect of stress and elevated cortisol on the morbidity, prevalence, clinical disease and histological presentation associated with mycobacterial infections in zebrafish. Minimizing husbandry stress may be effective at reducing the severity of outbreaks of clinical mycobacteriosis in zebrafish facilities.  相似文献   

7.
Mycobacterium spp. and Photobacterium damselae subsp. piscicida are recognized as the most frequent causative agents of granulomatous lesions in fish. Although frequent episodes of mycobacterial infections have been reported in wild fish worldwide, only sporadic cases have been documented to date in Italy. To investigate for the presence of lesions referable to mycobacteriosis and to identify the mycobacterial species involved, a total of 159 wild mullets were fished from the eastern coast of the Ligurian Sea, killed and necropsied. Liver and spleen samples were collected from all fish for histopathological and microbiological analyses. Molecular investigations for identification of Photobacterium damselae subsp. piscicida were performed. Gross examination revealed granulomatous lesions in one animal; microscopically, 42.14% of fish displayed granulomas with various histological features, 19.50% resulted positive at Ziehl–Neelsen staining, and were confirmed as mycobacterial lesions by culture. The identified colonies were characterized as M. fortuitum, M. abscessus, M. flavescens, M. chelonae, M. septicum and M. nonchromogenicum. In all, 35% of animals resulted positive for Photobacterium damselae subsp. piscicida. These data suggest widespread mycobacterial infection also by Photobacterium damselae subsp. piscicida infections in wild fish. Moreover, the pathogenicity of some mycobacterial species, previously considered as saprophytic, was demonstrated.  相似文献   

8.
The antigenicity of extracellular products (ECPs) derived from Mycobacterium spp. isolated from snakehead, Channa striata (Bloch), and Siamese fighting fish, Betta splendens (Regan), were examined by immunoblotting and enzyme-linked immunosorbent assay (ELISA) using sera collected from immunized rabbits, mice and fish (rainbow trout). All three species responded to a 65-kDa protein present in both the ECPs and whole cell sonicates (WCSs) from a variety of Mycobacterium spp. Cross-reactivity of anti- M. tuberculosis and anti-human heat-shock protein monoclonal antibodies (MAbs), and the presence of fibronectin binding proteins secreted into ECPs of mycobacteria were also examined. The MAbs against human 60-kDa heat-shock protein cross- reacted with the band at 65 kDa in the ECPs of TB1 (isolated from snakehead fish) and the type strain M. marinum, while the anti- M. tuberculosis MAb F29–47 elicited a strong reaction with a band at 21 kDa with most of the ECPs from mycobacterial strains examined. The major fibronectin-binding proteins were located between 21 and 25 kDa. The 65-kDa protein from ECPs of Mycobacterium spp. proved strongly immunogenic to rabbits, mice and fish. Rabbit antiserum against the 65-kDa protein from strain TB267 reacted with many non- Mycobacterium WCSs, and therefore, the 65-kDa protein from Mycobacterium spp. is believed to be a common protein found in many fish bacterial pathogens.  相似文献   

9.
The disease status of Australian salmonids: bacteria and bacterial diseases   总被引：2，自引：0，他引：2  
Abstract. Eleven freshwater salmonid hatcheries in southern Australia were surveyed for bacterial pathogens and diseases between 1981 and 1985, Twenty-five populations of fish were examined in the study, representing a total of 2755 fish, from which kidney, liver, spleen, and in some cases peritoneum, blood and faeces were cultured. Bacteria of pathogenic significance isolated included Aeromonas hvdrophila, Streptococcus sp., Lactobacillus piscicola, Yersinia ruckeri, Mycobacterium fortuitum, M. chelonei and a filamentous acid-fast organism of uncertain taxonomic position. Lacto-bacillus piscicola and Streptococcus sp. were associated with clinical and subclinical peritonitis. Mycobacterium chelonei was isolated from visceral granulomas in an externally normal fish. Aeromonas salmonicida, Renibacterium salmoninarum and Edwardsiella tarda were not isolated, indicating that the diseases furunculosis, bacterial kidney disease and edwardsiellosis are exotic to Australian salmonids. Similarly, while Y. ruckeri was isolated, enteric redmouth disease had not been recorded and is considered an exotic disease.  相似文献   

10.
A survey was carried out on occurrence of Mycobacterium marinum in fish kept in aquaria and those living in their natural environment. Species‐specific qPCR targeting the erp and IS2404 genes together with the conventional culture method were used. The analysis of 72 ornamental fish (n = 216 samples: gills, muscle and intestine) collected from aquaria revealed the presence of M. marinum in 30 individuals (41.7%) of whom 17 (23.6%) were later culture positive. Culture‐independent detection revealed the presence of M. marinum in 16 of 83 environmental samples (19.3%) collected in aquaria. The presence of viable M. marinum cells was later confirmed in 5 samples (6.0%). No qPCR or culture positivity was observed when 123 groundwater fish and their corresponding environmental samples (n = 142) were analysed.  相似文献   

11.

Ornamental fish farming is globally a key sector of aquaculture. The purpose of this study was to report on the parasitic fauna of ornamental fish from seven farms in the East Azerbaijan province in northwestern Iran. Between November 2020 and February 2021, a total of 600 freshwater ornamental fish of six species, including goldfish (Carassius auratus), angel (Pterophyllum scalare), guppy (Poecilia reticulata), dwarf gourami (Colisa lalia), swordtail (Xiphophorus helleri), and cichlid (Cichlasoma sp.) were collected for parasitological analysis. Six ciliate protozoan species (Trichodina mutabilis, Trichodina nobilis, Trichodina spp., Heteropolaria lwoffi, Ichthyophthrius multifiliis, and Chilodonella spp.), three species of monogenean trematodes (Dactylogyrus dulkeiti, Dactylogyrus spp. and Gyrodactylus spp.), two species of crustacean arthropods (Lernaea cyprinacea and Argulus japonicus), and a nematode (Capillaria spp.) were identified among the examined fish. Parasites were detected in the fish from 5 of 7 farms, with an overall parasitic prevalence in 26.33% (158/600) of the fish. Fish infection rates with protozoans, monogenean trematodes, crustacean arthropods, and nematodes were 16.83, 13.17, 4, and 0.33% respectively. The highest prevalence was found in X. helleri infected with Gyrodactylus spp. and P. scalare infested with Trichodina spp. Moreover, 9/100 and 10/100 of goldfish were infected with A. japonicus and L. cyprinacea, compared to 2/500 and 3/500, respectively, for all other species in combination, which is a statistically significant result (p?<?0.01). Assessment of farmed fish parasitic fauna is important to inhibit the spread of infections, ensure fish production and improve fish health.

  相似文献   

12.
A survey was performed on ornamental fish imported into the EU to detect viral agents belonging to the genus Ranavirus. The objective was to gain knowledge of the potential for these systemic iridoviruses to gain entry into the EU via international trade in ornamental fish. A total of 208 pooled samples, representing 753 individual fish, were tested. The samples included 13 orders and 37 families, originating from different countries and continents. Tissues from fish that died during or just after transport were collected and examined by standard virological techniques in epithelioma papulosum cyprini cells, by transmission electron microscopy and by PCR for the detection of the major capsid protein and DNA polymerase gene sequences of ranaviruses. Virus was isolated from nine fish species but ranavirus was not identified in those samples. The results suggest that ranaviruses are not highly prevalent in ornamental fish imported into the EU.  相似文献   

13.
Keeping fish is a popular pastime in South Africa and the majority of ornamental fish are imported. A pilot study was initiated to examine the health status of ornamental freshwater fishes imported to South Africa. Four groups of thirty fish each were examined for the presence of external parasites, and processed for virus isolation and for bacterial and mycobacterial culture. The groups consisted of goldfish (Carassius auratus), koi (Cyprinus carpio), guppies (Poecilia reticulata) and cardinal tetras (Cheirodon axelrodi). Mycobacterium fortuitum was isolated from the goldfish and koi. No other significant bacteria were isolated and virus culture was negative for all groups. Skin scrapings and wet gill preparations were made to detect external parasites. Parasites were identified from fixed material. External parasites included Trichodina mutabilis, Ichthyophthirius multifiliis, ciliophorans of the genus Tetrahymena, and monogeneans belonging to the genera Dactylogyrus and Gyrodactylus. This is the first report of Trichodina mutabilis in South Africa. Diseases imported with ornamental fish pose a risk to both indigenous fish populations and the aquaculture industry. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

14.
The natural route by which fish become infected with mycobacteria is unknown. Danio rerio (Hamilton) were exposed by bath immersion and intubation to Mycobacterium marinum and Mycobacterium peregrinum isolates obtained from diseased zebrafish. Exposed fish were collected over the course of 8 weeks and examined for the presence of mycobacteriosis. Mycobacteria were consistently cultured from the intestines, and often from the livers and spleens of fish exposed by both methods. Mycobacteria were not observed in the gills. Histological analysis revealed that fish infected with M. marinum often developed granulomas accompanied by clinical signs of mycobacteriosis, while infection with M. peregrinum infrequently led to clinical signs of disease. Passage of the bacteria through environmental amoebae (Acanthamoeba castellani) was associated with increased growth of M. peregrinum over the course of 8 weeks, when compared to infection with the bacteria not passed through amoebae. The results provide evidence that zebrafish acquire mycobacteria primarily through the intestinal tract, resulting in mycobacterial dissemination.  相似文献   

15.
A cross-sectional survey of Renibacterium salmoninarum infection in farmed rainbow trout (RBT) and wild fish populations was carried out in 10 farms and six river catchments, respectively, in England and Wales. The majority of the wild fish were sampled in 1998 and the farmed fish in 2000. Grayling, Thymallus thymallus, and brown trout, Salmo trutta, were the main wild species sampled. Two fish, one grayling and one salmon, Salmo salar, were R. salmoninarum culture-positive, compared with 40 confirmed polymerase chain reaction-positive wild fish. The highest prevalence of R. salmoninarum infection was found in grayling in rivers with RBT farms with a history of R. salmoninarum infection. One hundred and fifty fish were sampled from each RBT farm, but none of the fish was found to be R. salmoninarum-positive. Evidence was found, for the first time, for the presence of R. salmoninarum in an eel, Anguilla anguilla.  相似文献   

16.
Mycobacteriosis in fish is a chronic progressive ubiquitous disease caused by Mycobacterium marinum, M. gordonae and M. fortuitum in most cases. The aim of this study was to describe the morphology and distribution of lesions in 322 freshwater ornamental fish across 36 species. Granulomatous inflammation was diagnosed by gross examination and histopathology testing in 188 fish (58.4%); acid‐fast rods (AFR) were determined in only 96 (51.1%) fish from 19 species after Ziehl–Neelsen staining. The most often affected organs with AFR were the kidney (81.2%), digestive tract (54.1%), liver (48.2%), spleen (45.9%) and skin (21.2%); sporadically, AFR were found in the branchiae (9.4%) and gonads (4.7%). In 14 randomly selected fish originating from four different fish tanks, the distribution of mycobacterial infection was studied by culture examination of the skin, gills, muscle tissue, digestive tract, liver, spleen and kidney. In 12 fish, the species M. marinum, M. gordonae, M. fortuitum, M. triviale, and M. avium subsp. hominissuis (serotypes 6 and 8 and genotype IS901? and IS1245+) were detected; mixed infection caused by different mycobacterial species was documented in five of them.  相似文献   

17.
Disease due to non‐tuberculous mycobacteria (NTM) is common in fish. Current recommendations focus on outbreak management by depopulating entire fish stocks and disinfecting tanks. Treatment is not advocated. Treatment may be appropriate, however, where individual, valuable fish are concerned. ZSL London Zoo managed an outbreak of mycobacteriosis in a valuable group of imported F1 captive‐bred Australian lungfish (Neoceratodus fosteri) by depopulation, isolation, extensive testing and daily oral antibiotic treatment. Four species of Mycobacterium (M. marinum, M. fortuitum, M. chelonae and M. peregrinum) were involved in this outbreak, each with unique antibiotic sensitivities. Triple therapy with rifampicin, doxycycline and enrofloxacin for 8 months was the most effective antibiotic combination, resulting in full disease resolution. No side effects were noted and, more than 18 months post‐treatment, no recurrence had occurred. This is the first report of mycobacterial disease in lungfish and the first report of a polymycobacterial outbreak in fish involving these four species of Mycobacterium. This report demonstrates the value of extensive isolation and identification. Also, as therapies currently advised in standard texts did not reflect the antibiotic sensitivity of the NTM found in the fish reported here, we recommend that antibiotic treatment should always be based on sensitivity testing.  相似文献   

18.
Abstract. Bacteriologically sterile filtrates of 'tumorous' fish elicited formation of 'tumours' in vivo which were morphologically indistinguishable from those described by Wessing & Bargen (1959). Attempts to isolate the putative aetiologic 'Virus' in primary and established cell cultures failed. When the lesions were examined for other compatible aetiologies, acid-fast stains revealed acid-fast bacilli and cultures grew Mycobacterium fortuitum . It is suggested that the 'kidney tumour virus' is actually soluble mycobacterial cell-fractions capable of eliciting tubercle formation in vivo .  相似文献   

19.
Based on microbiological and histopathological examinations and DNA sequencing, several outbreaks of mycobacteriosis in the reared sturgeons, including Chinese sturgeon (Acipenser sinensis Gray) and Amur sturgeon (Acipenser schrencki), were identified during 2009 to 2010. Forty‐nine isolates of non‐tuberculous mycobacteria(NTM)were isolated from 19 diseased sturgeons. In total, seven species of Mycobacterium were identified, namely, Mycobacterium chelonae, Mycobacterium marinum, Mycobacterium gordonae, Mycobacterium fortuitum, Mycobacterium szulgai, Mycobacterium arupense and Mycobacterium porcinum. Among them, M. marinum was found to be more prevalent (89.5%) compared with the other mycobacterial species. When two molecular biological methods, PCR‐DGGE (denaturing gradient gel electrophoresis) analysis and rpoB gene library sequencing, were used to analyse the mycobacterial DNAs extracted from the diseased fish tissues, mixed infections of two or three mycobacterial species were found being the predominant infection form (94.7%) in sturgeon mycobacteriosis. M. marinum was the only one species that caused sturgeon mycobacteriosis alone. Virulence assay showed that M. marinum possessed stronger pathogenicity to zebrafish killing 100% of fish in 28 days at 103 cfu/fish than the other species. These results suggested that M. marinum is the major pathogenic bacteria in sturgeon mycobacteriosis. To the best of our knowledge, this study is the first report on mycobacteriosis in farmed Chinese and Amur sturgeons as well as the first isolation of M. porcinum and M. arupense from fish.  相似文献   

20.
Fish are commonly infected with non‐tuberculous mycobacteria (NTM), which should be regarded as potential pathogens when handling aquarium fish and equipment. This study examined 107 aquarium fish from pet shops. Cultivation of the fish samples using different selective media was conducted for identification of NTM. Isolates were identified using the GenoType Mycobacterium common mycobacteria and additional species assays, sequencing of the 16S rRNA and rpoB genes, and real‐time PCR assay for identification of Mycobacterium (M.) marinum. Among the investigated fish, 79.4% (85/107) were positive for mycobacteria, with 8.2% (7 of 85) having two mycobacterial species present. Among the positive fish, the common pathogens M. marinum, Mycobacterium fortuitum (M. fortuitum group) and Mycobacterium chelonae were identified in approx. 90% of fish and other NTM species in 10%, including Mycobacterium peregrinum/septicum, Mycobacterium gordonae, Mycobacterium arupense, Mycobacterium kansasii, Mycobacterium ulcerans and Mycobacterium setense. The well‐known human pathogen M. marinum was present in 10.6% of the positive fish (9 of 85). The species of mycobacteria identified in the study are not only recognized as aquarium fish pathogens, but can also cause pathology in humans. Microbiological and clinical communities should therefore be sensitized to the role of NTM in infections associated with exposure to aquarium fish.  相似文献   

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