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Objective: Both infected subdural hematoma (ISH) and Edwardsiella tarda infections are rare in humans. E. tarda is a motile, facultative anaerobic, gram-negative rod bacterium, which is isolated from fresh or brackish water, but not usually from humans. Extra-intestinal E. tarda infections are rare and might cause severe clinical symptoms. However, ISH caused by E. tarda has not been reported previously. We report the first case of ISH due to E. tarda.Patient: A 76-year-old man was admitted to our hospital with a headache, loss of appetite, and nausea. Computed tomography revealed bilateral subdural hematoma.Results: We performed burr hole drainage. A hematoma with pus was found on the left side and chronic hematoma was found on the right side. Consequently, we diagnosed him with ISH on the left side and chronic subdural hematoma on the right side. E. tarda was detected in a culture from the hematoma with pus on the left side. As postoperative antibiotic therapy, we administered ceftriaxone and metronidazole for 47 days. The patient was discharged with no residual neurological deficit.Conclusion: Our case implied that favorable outcomes can be obtained by drainage and appropriate antibiotic therapy for ISH caused by E. tarda.
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RESUMEN Se aislaron 120 morfotipos bacterianos de intestino de tilapia y se seleccionaron según su actividad antibacteriana contra patógenos como Aeromonas hydrophila, Streptococcus agalactiae y Edwardsiella tarda, su capacidad de adherencia a mucus intestinal y cinética de crecimiento. Las bacterias seleccionadas se identificaron mediante secuenciación de 16S rRNA y se identificaron como Exigobacterium sp. l9, Enterococcus faecalis I15 y Myroides odoratimimus l19. Además, se evaluó su efecto in vivo sobre el crecimiento de los peces, mediante su adición al alimento de juveniles de Oreochromis niloticus (106 UFC / g, por 15 días). Se determinó la supervivencia luego de un desafío experimental con Edwardsiella tarda por inyección intraperitoneal (100 µL 105 UFC / mL). Las tres bacterias seleccionadas incrementaron la tasa de crecimiento específico, redujeron la mortalidad de los peces durante el desafío experimental con E. tarda y no causaron mortalidad durante la adición en el alimento. Los efectos positivos in vivo se relacionan posiblemente con actividad in vitro; sin embargo, por motivos de bioseguridad se recomienda efectuar estudios posteriores a Exigobacterium sp. l9y E. faecalis I15 dado que se han reportado miembros de este género como causantes de mortalidad en peces, mientras que en el caso de M. odoratimimus l19, es necesario efectuar futuros estudios para verificar su actividad positiva a mayor escala productiva.
ABSTRACT 120 bacteria were isolated from tilapia intestine and screened according to the antibacterial activity against pathogens such as Aeromonas hydrophila, Edwardsiella tarda and Streptococcus agalactiae, the ability to adhere to intestinal mucus and growth kinetics. The selected bacteria were identified by 16S rRNA sequencing of and were identified as Exigobacterium sp. I9, Enterococcus faecalis l15 and Myroides odoratimimus l19. Furthermore, the in vivo effect on fish growth was assessed by the addition of selected bacteria to juvenile Oreochromis niloticus feed (106 CFU / g, for 15 days). Survival was also determined after a challenge by intraperitoneal injection of E. tarda (100 µL of 105 UFC / mL). The three selected bacteria increased the specific growth rate, reduced mortality of fish during the experimental challenge with E. tarda and did not cause mortality during the addition in the feed. The positive effects observed in vivo are possibly associated with in vitro activity; however, for biosafety reasons, it is recommended that further studies of Exigobacterium sp. l9 and E. faecalis l15 may be carried out since this genus have been reported of as causative agents of fish mortality, whereas in the case of M. odoratimimus l19, verification of positive effects at a higher production scales is desirable.
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Our studies tried to demonstrate Eha (Et haemolysin activator) could regulate the resistance of the bacterium against acidification to survive in the macrophage and explain its underlying molecular mechanism.When the bacteria infected the macrophages at time intervals,intracellular survival rate in bafilomycin-treated macrophages was higher than that with untreated cells,and the rate of wild type ET 13 was higher than that of its eha mutant,respectively (P＜0.05).The survival rate of the wild type was higher than that of the mutant under acid treatment (P＜0.05).To determine the conditions that induced the highest eha expression,we constructed a pMP220-Peha LacZ plasmid and determined the lacZ expression under different conditions.After exposure of pH6.3 medium for 2 h time,we performed the whole transcriptomic profiles of the wild type and mutant by RNA-sequencing.We identified 147 differentially-expressed genes ([log2 ratio| ≥1),113 and 34 of which were significantly up-and down-regulated,respectively in the mutant,comparing with the wild type.These findings were validated by qRT-PCR.GO functional analysis revealed that these genes were divided into 25 categories,including the bacterial catalysis,cellular composition,combination,localization,metabolism,processing,and transportation.Based on the KEGG database,these genes were distributed in 55 pathways,such as two-component system,ABC transporters,and microbial metabolism in diverse environments.Overall,Eha is an important regulator to affect all kinds of target genes and pathways for E.tarda to adapt to an acid environment.These results could be helpful for further investigations of the mechanisms by which E.tarda survives in macrophages.
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O presente trabalho relata um surto de mortalidade de tambacus (Colossoma macropomum x Piaractus mesopotamicus) criados em tanques escavados da Fazenda-Escola da UCDB. Os peixes apresentaram sintomas clínicos de letargia, anorexia, aumento da produção de muco, nado desordenado e comportamento de buscar a superfície da água. Ao exame necroscópico de três peixes foram evidenciadas hemorragias nas nadadeiras e pele, opacidade de córnea, hemoperitôneo, distensão e repleção da vesícula biliar e congestão e hemorragia do tubo digestivo. O exame microbiológico dos materiais coletados das lesões dos tambacus foi positivo para a bactéria Edwardsiella tarda. A análise de qualidade de água indicou grande quantidade de fitoplânctons que proliferaram em função do excesso de matéria orgânica, caracterizando a eutrofização da água. Atribuiu-se a causa da morte dos tambacus à infecção oportunista pela E. tarda, favorecida pelo desequilíbrio devido ao excesso de matéria orgânica em suspensão na água. As mortes cessaram após a correção dos parâmetros da qualidade da água do tanque.
An outbreak of mortality of tambacus (Colossoma macropomum x Piaractus mesopotamicus) cultivated in dug tanks at UCDB was reported. Animals had clinical surface symptoms of lethargy, anorexia, increased mucus production, cluttering and swimming toward the water. Macroscopic examination of three fishes showed hemorrhages of the fins and skin, corneal opacity, hemoperitoneum, gallbladder distension and repletion, congestion and hemorrhages of the digestive tract. Water quality analysis indicated large amounts of phytoplankton that proliferated as a result of the excessive organic matter causing eutrophication of the water. The microbiological examination of tambacus lesions revealed the presence of the bacterium Edwardsiella tarda. The cause of the tambacus death was attributed to opportunistic infection by E. tarda, favored by the imbalance due to the intense organic matter in suspended in the water. Deaths stopped after the correction of the water quality parameters.
Subject(s)
Animals , Characidae/microbiology , Edwardsiella tarda/isolation & purification , Edwardsiella tarda/pathogenicity , Eutrophication , Waterborne DiseasesABSTRACT
A multiplex PCR protocol was established to simultaneously detect major bacterial pathogens in olive flounder (Paralichthys olivaceus) including Edwardsiella (E.) tarda, Streptococcus (S.) parauberis, and S. iniae. The PCR assay was able to detect 0.01 ng of E. tarda, 0.1 ng of S. parauberis, and 1 ng of S. iniae genomic DNA. Furthermore, this technique was found to have high specificity when tested with related bacterial species. This method represents a cheaper, faster, and reliable alternative for identifying major bacterial pathogens in olive flounder, the most important farmed fish in Korea.
Subject(s)
Animals , Edwardsiella tarda/genetics , Enterobacteriaceae Infections/diagnosis , Fish Diseases/diagnosis , Fisheries/methods , Flatfishes , Multiplex Polymerase Chain Reaction/economics , Sensitivity and Specificity , Streptococcal Infections/diagnosis , Streptococcus/geneticsABSTRACT
Edwardsiella tarda is a member of the family Enterobacteriaceae, commonly found in tropical and subtropical aquatic environments. Most E. tarda infections are linked to exposure to water or animals that inhabit water. However, it is still an uncommon pathogen in humans and causes mainly watery diarrhea. We describe a case of liver abscess caused by E. tarda. A 60-yr-old Korean man, with underlying diabetes mellitus, had a 10-day stay in Egypt 15 days before presentation. Ultrasound-guided percutaneous transhepatic abscess aspiration was performed. Pus culture revealed E. tarda, which was susceptible to all the antibiotics commonly used against Gram-negative organisms. The patient was treated with cefobactam for 10 days and piperacillin/tazobactam for another 5 days combined with an additional abscess aspiration due to recurrent fever. This therapy led to clinical improvement. The possible source of infection in this case may have been the drinking water supplied during travel in Egypt, but we cannot completely rule out a domestic source, because a liver abscess caused by E. tarda has been reported in a Japanese patient without travel history. Considering the Korean custom of eating raw fish or shrimp, climate changes, and increasing international travel, infections due to E. tarda may increase in Korea. Clinical microbiologists should be aware of this potential pathogen, and prompt investigation of the infection source and site is needed.
Subject(s)
Animals , Humans , Abscess , Anti-Bacterial Agents , Asian People , Climate Change , Diabetes Mellitus , Diarrhea , Drinking Water , Eating , Edwardsiella , Edwardsiella tarda , Egypt , Enterobacteriaceae , Fever , Korea , Liver , Liver Abscess , Suppuration , WaterABSTRACT
Objective To construct, express and identify the anti-idiotypic antibody single chain variable fragment (scFv) against Edwardsiella tarda. Methods By using RT-PCR method, the variable regions of the heavy and light chain of the anti-idiotypic monoclonal antibody (mAb) 1E11 against Edwardsiella tarda were cloned and joined with a (Gly_4ser)_3 linker, and the scFv in the orientation of V_L-linker-V_H was constructed. It was then cloned into vector plasmid pET-28a, expressed in Escherichia coli BL21(DE3), and confirmed by SDS-PAGE, Western blot and ELISA. Results The recombinant scFv could be expressed in E.coli BL21 (DE3) in a fusion protein pattern. The expression product was in the form of an inclusion body and the purified fusion protein was obtained after being purified and refolded. The SDS-PAGE and Western blot analysis showed that the molecular had the binding activity to the antigen. Conclusion The recombinant anti-idiotype scFv has been successfully constructed and expressed in E.coli BL21 (DE3), providing the basis and potential for preparation of genetically engineered vaccine against Edwardsiella tarda.
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Investigaram-se as causas da mortalidade de peixes ocorrida em janeiro de 2005 na bacia do Rio São Francisco, Brasil. Edwardsiella tarda foi isolada dos rins de pacu Myleus micans. O isolado, denominado Et-LIS, caracterizado por bastonetes Gram negativos móveis, foi identificado por testes bioquímicos e confirmado pelo kit comercial Bactray. A susceptibilidade a 10 drogas das 12 testadas foi determinada pelo método de difusão de discos, enquanto as características de virulência foram avaliadas mediante inoculação experimental em Cyprinus carpio e em Oreochromis spp. Ambas as espécies desafiadas apresentaram sinais compatíveis com infecção por E. tarda. As tilápias (Oreochromis spp.) morreram 48h após a inoculação, enquanto as carpas (Cyprinus carpio) sobreviveram por 72h. Este é o primeiro relato da ocorrência de E. tarda em pacu.
Subject(s)
Animals , Edwardsiella tarda/isolation & purification , Fishes , Measures of Disease Occurrence , Mortality , Veterinary MedicineABSTRACT
Objective To construct,express and identify the anti-idiotypic antibody single chain variable fragment(scFv) against Edwardsiella tarda.Methods By using RT-PCR method,the variable regions of the heavy and light chain of the anti-idiotypic monoclonal antibody(mAb) 1E11 against Edwardsiella tarda were cloned and joined with a(Gly4Ser)3 linker,and the scFv in the orientation of VL-linker-VH was constructed.It was then cloned into vector plasmid pET-28a,expressed in Escherichia coli BL21(DE3),and confirmed by SDS-PAGE,Western blot and ELISA.Results The recombinant scFv could be expressed in E.coli BL21(DE3) in a fusion protein pattern.The expression product was in the form of an inclusion body and the purified fusion protein was obtained after being purified and refolded.The SDS-PAGE and Western blot analysis showed that the molecular weight of scFv protein was 27 ku.Indirect ELISA confirmed that the scFv had the binding activity to the antigen.Conclusion The recombinant anti-idiotype scFv has been successfully constructed and expressed in E.coli BL21(DE3),providing the basis and potential for preparation of genetically engineered vaccine against Edwardsiella tarda.
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A rural property was observed for one year to obtain seasonal observations of Edwardsiella septicemia in tilapias (Oreochromis sp.) from an integrated fish farm (using pig excrements as food). Fifty tilapias on summer, forty-five on autumn, fifty-five on winter and one hundred and five on spring were collected and evaluated microbiologically for the presence of Edwardsiella tarda. Samples of the external surface (skin, gills and fin), intestines and muscle were analyzed. Fishes were transported alive to the laboratory, and maintained for five days for observation. The external signs observed were opacity of cornea, respiratory difficulty, disordered swimming, nodules on gills, hemorrhagic lesions under the skin and fins and incoordination of the posterior part of the body. In general, after three days of observation, the tilapias died. At necropsy, ascites with the distension of the celomatic cavity, hemorrhagic and necrotic lesions in the liver, spleen and kidneys were found. Hemorrhagic enteritis was observed in the gut tube. Edwardsiella tarda isolated presented the following biochemical profile: negative urea, sucrose, phenylalanine desaminase and malonate utilization, and positive indole, methyl red, H2S, motility, glucose with gas production and lysine decarboxylase. The mortality rates were 69.9% on spring, 63.6% on winter, 48.0% on summer and 40.0% on autumn, highest rates occurring on spring and winter (P 0,05).
Com o objetivo de estudar a variação sazonal da septicemia dos peixes tropicais provocada por Edwardsiella tarda foram observadas 50 tilápias (Oreochromis sp.) no verão, 45 no outono, 55 no inverno e 105 na primavera. Os peixes doentes apresentavam opacidade de córnea, dificuldade respiratória, nado desordenado, nódulos nas brânquias e lesões hemorrágicas na pele e nadadeiras. Após três dias de observação as tilápias morriam naturalmente. Nas necrópsias foi encontrado ascite com distensão da cavidade celomática e lesões hemorrágicas e necróticas no fígado, baço e rins. No interior do tubo digestivo observou-se enterite hemorrágica. Isolou-se Edwardsiella tarda a partir de provas positivas para H2S, lisina, indol, motilidade e glicose com gás. Os índices de mortalidade foram: na primavera 69,9%, no inverno 63,6%, no verão 48,0% e no outono 40,0%.
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Aim study the characteristic of the hemolysin of Edwardsiella tarda. Methods Manner plate assay, contact hemolysis and supernatant assay were used. Result discuss the factors about affecting hemolysis activity and testing have been discussed. Conclusion there are at least two kinds of hemolysins of Edwardsiella tarda, activity of which is different with circumstance changing.
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Objective:To study the antigenicity of OMP extracted from Edwardsiella tarda.Methods:ELISA, Bactericidal test, Agglutinating test and Western blotting were used for testing the antigenic titers and immunogenicity of OMP.Results:In immunoblotting, by using ATCC15947 OMP antibody, the non pathgenic strains were negative, while all pathogenic strains except Et 122 gave positive results and had OMP bands of 33k, 35k, 38k, and 45k. OMPs of both ATCC 15947 and JEL4 could induce high antibody titers. Further more, the antibodies evoked by OMPs of ATCC 15947 of 33k or 35k could also protected mice to some degree when diluted.Conclusion:The 33k, 35k, 38k, and 45k of OMPs may be protective antigens, and the OMPs of Et could be a candidative component for vaccine.