Antimicrobial property of lemongrass (Cymbopogon citratus) oil against pathogenic bacteria isolated from pet turtles / 한국실험동물학회지

The usage of essential oils as antimicrobial agents is gaining attention. Besides, pet turtles were known to harbor a range of pathogenic bacteria while the turtle keeping is a growing trend worldwide.The current study examined the antimicrobial activity of lemon grass oil (LGO) against seven species of Gram negative bacteria namely; Aeromonas hydrophila, A. caviae, Citrobacter freundii, Salmonella enterica, Edwardsiella tarda, Pseudomonas aeruginosa, and Proteus mirabilis isolated from three popular species of pet turtles. Along with the results of disc diffusion, minimum inhibitory and minimum bactericidal concentration (MIC and MBC) tests, LGO was detected as effective against 6 species of bacteria excluding P. aeruginosa. MIC of LGO for the strains except P. aeruginosa ranged from 0.016 to 0.5% (V/V). The lowest MIC recorded in the E. tarda strain followed by A. hydrophilla, C. freundii, P. mirabilis, and S. enterica. Interestingly, all the bacterial species except E. tarda were showing high multiple antimicrobial resistance (MAR) index values ranging from 0.36 to 0.91 upon the 11 antibiotics tested although they were sensitive to LGO.

Mortalidade de tambacus (Colossoma macropomum x Piaractus mesopotamicus) infectados por Edwardsiella tarda / Mortality of tambacus (Colossoma macropomum x Piaractus mesopotamicus) infected by Edwardsiella tarda

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.

Adhesive and invasive capacities of Edwarsiella tarda isolated from South American sea lion

Edwarsiella tarda is a zoonotic bacterium that can be isolated from humans, animals and the environment. Although E. tarda is primarily considered a fish pathogen, it is the only species of its genus considered to be pathogenic for humans as well. A survey of zoonotic intestinal bacteria in fresh feces from South American sea lions (SASL) Otaria flavescens, reported E. tarda as the most frequently isolated species. In this study, we used HEp-2 cells to establish in vitro the adherence and invasive ability of 17 E. tarda strains isolated from SASL fecal material. All the strains were able to adhere and invade HEp-2 cells with adhesion and invasion percentages ranging from 56 to 100% and 21 to 74%, respectively. Despite the expression of these pathogenic factors, further investigation is needed to determine whether this bacterium could play a role as primary pathogen for this and other species of pinnipeds.

Development of a multiplex PCR assay to detect Edwardsiella tarda, Streptococcus parauberis, and Streptococcus iniae in olive flounder (Paralichthys olivaceus)

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.

Liver Abscess Caused by Edwardsiella tarda: A Case Report

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.

Edwardsiella tarda sepsis with multiple liver abscesses in a patient with Cushing's syndrome.

Edwardsiella tarda is very seldom a cause for gastroenteritis in humans. This organism can also cause extraintestinal infections, such as soft tissue infections, meningitis, peritonitis, osteomyelitis, endocarditis and hepatobiliary tract disease, particularly in the setting of compromised immunity. We describe, for the first time a case of E. tarda sepsis with multiple liver abscesses associated with Cushing's syndrome as a result of recreational aquatic exposure.

Isolation and characterizaton of Edwardsiella tarda from pacu Myleus micans / Isolamento e caracterização de Edwardsiella tarda em pacu Myleus micans

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.

Liver abscess caused by Edwardsiella tarda biogroup 1 and identification of its epidemiological triad by ribotyping.

Two clinical isolates and an environmental isolate of Edwardsiella tarda biogroup 1 (ETB1), recovered from liver pus, the stool specimen and from the pond water of the village of the patient, diagnosed to have liver abscess, were found to be identical by protein fingerprinting and ribotyping. It can be construed that the pond water served as the source of infection. The epidemiological triad of the agent (ETB1), host (the patient) and environment (pond water) was thus established. This is the first report in which the triad for extraintestinal Edwardsiellosis caused by ETB1 has been identified. This also constitutes the first report of typing of ETB1 strains by SDS-PAGE and ribotyping.

Empiema pleural causado por Edwardsiella tarda / Pleural empyema caused by Edwardsiella tarda

Os autores descrevem o primeiro caso registrado de empiema pleural causado por Edwardsiella tarda, uma bactéria Gram negativa, e fazem uma revisão da literatura das infecções causadas por este patógeno

Edwardsiella tarda endotoxin as an immunopotentiator in Singhi, Heteropneustes fossilis fingerlings.

Endotoxin of E. tarda grown in brain heart infusion broth at 30 degrees C for 18 hr was extracted by differential centrifugation. Fingerlings of H. fossilis (weighing 1-2 g) were allowed for hyperosmotic infiltration in the endotoxin at the rate of 0,2,4,8,16 and 20 mg/l. Mortality varied from 20-50% at 2 to 20 mg/ml. Toxin treated fishes were challenged 21 days post treatment with the same E. tarda strain containing 2.1 x 10(9) CFU/ml. There was 80% mortality in the control group whereas only 20% mortality in toxin treated group at 2 mg/l concentration after challenge with homologous E. tarda. Subsequently a second challenge of E. tarda was given to the survivors of fish one month after first challenge using same concentration where no mortality could be observed. It was concluded that the endotoxin could enhance percentage of survival against E. tarda infection in Singhi.

Effects of Sodium Alginate on the Non-Specfic Defense System of the Common Carp ( Cyprinus carpio L. ) / 대한면역학회지

Carp which receive intraperitoneal injections of sodium alginate show a high survival rate after being challenged with Edwardsiella tarda. To elucidate the immunoenhancement by sodium alginate, its effects on the non-specific defense system of carp were investigated. Sodium alginate had little influence either on the activity of the alternative complement pathway or on the phagocytic and respiratory burst activities of head kidney phagocytes (HKP), yet it greatly enhanced the migration of HKP to the peritoneal cavity (the site of injection) and concurrently elevated their phagocytic activity. The number of phagocytes mobilized by sodium alginate was 2 to 50 times greater than that by the well-known peritoneal exudate cell-eliciting agents when injected at the same dose. Accordingly, it is highly probable that the early elimination of challenge bacteria by such mobilized and activated phagocytes was responsible for the high survival rate of the alginateinjected fish. In chemotaxis assays, it was revealed that sodium alginate stimulated sorne leukocyte subpopulation (s) within the peritoneal cavity to produce and/or secrete chemotactic factor (s), while concurrently enhancing the sensitivity of HKP to the factor (s).