Bacteriophages in the control of pathogenic vibrios

Vibrios are common inhabitants of marine and estuarine environments. Some of them can be pathogenic to humans and/or marine animals using a broad repertory of virulence factors. Lately, several reports have indicated that the incidence of Vibrio infections in humans is rising and also in animals constitute a continuing threat for aquaculture. Moreover, the continuous use of antibiotics has been accompanied by an emergence of antibiotic resistance in Vibrio species, implying a necessity for efficient treatments. One promising alternative that emerges is the use of lytic bacteriophages; however, there are some drawbacks that should be overcome to make phage therapy a widely accepted method. In this work, we discuss about the major pathogenic Vibrio species and the progress, benefits and disadvantages that have been detected during the experimental use of bacteriophages to their control.

Pathogenic Vibrio species isolated from estuarine environments (Ceará, Brazil) - antimicrobial resistance and virulence potential profiles

ABSTRACT Detection of virulent strains associated with aquatic environment is a current concern for the management and control of human and animal health. Thus, Vibrio diversity was investigated in four estuaries from state of Ceará (Pacoti, Choró, Pirangi and Jaguaribe) followed by antimicrobial susceptibility to different antimicrobials used in aquaculture and detection of main virulence factors to human health. Isolation and identification were performed on TCBS agar (selective medium) and dichotomous key based on biochemical characteristics, respectively. Nineteen strains of genus Vibrio were catalogued. Vibrio parahaemolyticus (Choró River) and V. alginolyticus (Pacoti River) were the most abundant species in the four estuaries. All strains were submitted to disk diffusion technique (15 antimicrobials were tested). Resistance was found to: penicillin (82%), ampicillin (54%), cephalotin (7%), aztreonan (1%), gentamicin, cefotaxime and ceftriaxone (0.5%). Five pathogenic strains were chosen to verification of virulence factors. Four estuaries showed a high abundance of species. High number of tested positive strains for virulence is concerning, since some of those strains are associated to human diseases, while others are known pathogens of aquatic organisms.

Occurrence of potentially pathogenic Vibrio in oysters (Crassostrea gigas) and waters from bivalve mollusk cultivations in the South Bay of Santa Catarina

Introduction This research aimed to identify and quantify potentially pathogenic Vibrio from different cultivations of bivalve shellfish in the State of Santa Catarina, Brazil, and water regions in the South Bay, as well as correlate the incidence of these microorganisms with the physicochemical parameters of marine waters. Methods Between October 2008 and March 2009, 60 oyster and seawater samples were collected from six regions of bivalve mollusk cultivation, and these samples were submitted for Vibrio counts. Results Twenty-nine (48.3%) oyster samples were revealed to be contaminated with one or more Vibrio species. The Vibrio parahaemolyticus and Vibrio vulnificus counts in the samples ranged from < 0.5 log10 Most Probable Number (MPN) g–1 to 2.3 log10 MPN g–1 oyster and from < 0.5 log10 MPN g–1 to 2.1 log10 MPN g–1 oyster, respectively. Of the 60 seawater samples analyzed, 44 (73.3%) showed signs of contamination with one or more vibrio species. The counts of V. parahaemolyticus and V. vulnificus in the samples ranged from < 0.3 log10 MPN·100mL–1 to 1.7 log10MPN·100mL–1 seawater and from < 0.3 log10 MPN·100mL–1 to 2.0 log10 MPN·100mL–1 seawater, respectively. A positive correlation between V. vulnificus counts and the seawater temperature as well as a negative correlation between the V. parahaemolyticus counts and salinity were observed. Conclusions The results suggest the need to implement strategies to prevent vibrio diseases from being transmitted by the consumption of contaminated bivalve shellfish. .

Isolation and characterization of infectious Vibrio sinaloensis strainsfrom the Pacific shrimp Litopenaeus vannamei (Decapoda: Penaeidae)

Infectious diseases especially those caused by bacterial and viral pathogens are serious loss factors in shrimp farming. In this study, bacteria were isolated from the gut and hepatopancreas of stressed shrimps obtained from a commercial farm. The isolates were screened on Thiosulfate citrate bile salt sucrose (TCBS) agar plates for the selection of Vibrio species. Presumptive vibrios were characterized through tests for hemolytic and enzymatic activity, hydrophobicity, growth and molecular identification. Three experimental infections were conducted in order to confirm the pathogenicity of selected bacterial strains VHPC18, VHPC23, VHPC24 and VIC30. In the third experimental challenge the LD50 was obtained, it lasted 10 days with 10 shrimp, weighing 6.9±1.1g, per tank. The treatments in triplicate were: (1) saline solution (control group); (2) 2×10(5)CFU/shrimp; (3) 4×10(5)CFU/shrimp; (4) 2×10(6)CFU/shrimp; (5) 4×10(6)CFU/shrimp, and (6) 8×10(6)CFU/shrimp. In all challenges, water parameters measured during the experimental period remained within optimum ranges. Pathogenicity tests confirmed that the mixture of four vibrio isolates, identified as Vibrio sinaloensis, was virulent for L. vannamei. The LD50 value was 1.178×10(5)CFU/g body weight. V. sinaloensis may act as opportunistic pathogens for cultured L. vannamei. Rev. Biol. Trop. 60 (2): 567-576. Epub 2012 June 01.

Las enfermedades de etiología infecciosa, especialmente las causadas por patógenos bacterianos y virales ocasionan graves pérdidas en el cultivo de camarón blanco Litopenaeus vannamei. En este estudio se caracterizo: la actividad enzimática y hemolítica; hidrofobicidad; crecimiento e identificación molecular de vibrios aislados del intestino y hepatopancreas de camarones estresados, obtenidos de una granja comercial, en medio Agar Tiosulfato Citrato Bilis Sacarosa. Además, se realizaron tres infecciones experimentales para confirmar la patogenicidad de las cepas bacterianas seleccionadas VHPC18, VHPC23, VHPC24 y VIC30. En la tercera infección experimental se obtuvo la LD50, el reto duro 10 días, con 10 camarones por tanque con un peso de 6.9±1.1g. Los tratamientos se realizaron por triplicado: (1) solución salina (grupo control); (2) 2×10(5)UFC/camarón; (3) 4×10(5)UFC/camarón; (4) 2×10(6)UFC/camarón; (5) 4×10(6)UFC/camarón y (6) 8×10(6)UFC/camarón. En todos los retos, los parámetros del agua permanecieron dentro de los intervalos óptimos. Las pruebas de patogenicidad confirmaron que la mezcla de cuatro aislados de Vibrio, identificados como Vibrio sinaloensis, fue virulenta para L. vannamei. El valor de la LD50 fue de 1.178×10(5)UFC/g de peso corporal. Los resultados permiten establecer que las cepas de V. sinaloensis pueden actuar como patógenos oportunistas en L. vannamei cultivado.

Vibrios patogênicos isolados em mexilhões (Perna perna) cultivados em sistema longline na Baía de Ilha Grande, RJ / Pathogenic vibrios isolated from mussels (Perna perna) cultivated in longline system in the Baía de Ilha Grande, RJ

Avaliaram-se 200 unidades de mexilhões (Perna perna) cultivados em sistemas longline na Baía de Ilha Grande, a fim de avaliar a presença de Vibrio spp. As amostras foram analisadas e submetidas a enriquecimento em água peptonada alcalina adicionada de 1% de NaCl, incubadas a 37ºC por 24 horas. Em seguida, os cultivos foram semeados em Agar tiossulfato citrato bile sacarose e as colônias suspeitas foram submetidas à caracterização bioquímica. Vibrio alginolyticus, V. harveyi e V. cincinnatiensis representaram as principais espécies (>70%) isoladas dos mexilhões in natura.

Isolamento e identificação molecular de Vibrio metschnikovii em amostras ambientais e análise do perfil de suscetibilidade a antibióticos / Isolation and molecular identification of Vibrio metschnikovii from environmental samples and analysis of antibiotic susceptibility profile

Introdução - Vibrio metschnikovii é um bacilo gram-negativo, potencialmente patogênico, amplamente distribuído e isolado de ecossistemas aquáticos e raramente de amostras clínicas de humanos. Na triagem laboratorial para espécies do gênero Vibrio, Vibrio metschnikovii é descartado por ser oxidase negativa, característica que o diferencia das demais espécies patogênicas. Em relação à pesquisa do perfil de suscetibilidade a antibióticos, esta é pouco realizada com isolados de origem ambiental. Objetivos - Isolar e identificar genotipicamente Vibrio metschnikovii de amostras ambientais e caracterizar seu perfil de suscetibilidade a antibióticos. Métodos - Um total de dez amostras foram obtidas de Março a Agosto de 2009, sendo uma de molusco (vôngole), três de peixe (pescada, sardinha e tainha) e seis de esgoto (três de esgoto bruto e três de esgoto tratado). O isolamento foi inicialmente realizado em meio seletivo para Vibrio (ágar TCBS) e a confirmação da espécie foi feita com iniciadores específicos através da PCR utilizando o DNA extraído pela técnica de choque térmico. O antibiograma foi realizado com base no documento M45-A CLSI 2006, seguindo a técnica de disco difusão, empregando quinze antibióticos. Foi realizada a pesquisa de genes de resistência a beta-lactâmicos e aminoglicosídeos. Resultados - De 123 isolados com características típicas para a espécie, 70 foram confirmados como Vibrio metschnikovii através da PCR, sendo 43 de amostras de molusco e peixes e 27 de esgoto.

Protein profile of Vibrio species isolated from diseased Penaeus monodon [Fab.]

Asia is the hub of aquaculture. In the Indian continents 75% culture development is on the East Coast along the Bay of Bengal. An attempt has been made to analyse the protein profile of Vibrio sp. isolated from Penaeus monodon. For the present study five isolates of Vibrio namely, V. alginolyticus, V. anguillarium, V. fluvialis, V. furnissi and V. mimicus were selected for protein estimation and SDS-PAGE analysis. The study revealed the total protein range from 10.4 +/- 0.17 to 12.3 +/- 0.26%, respectively. In the SDS-PAGE analysis the tested Vibrio sp. showed a single band of 38 kDa. The study revealed that the isolated Vibrio sp. showed 38 kDa protein band unique to pathogenic condition

Bacterial biofilm formation, pathogenicity, diagnostics and control: An overview.

Bacterial biofilms are complex, mono- or poly-microbialn communities adhering to biotic or abiotic surfaces. This adaptation has been implicated as a survival strategy. The formation of biofilms is mediated by mechanical, biochemical and genetical factors. The biofilms enhance the virulence of the pathogen and have their potential role in various infections, such as dental caries, cystic fibrosis, osteonecrosis, urinary tract infection and eye infections. A number of diagnostic techniques, viz., bright-field microscopy, epifluorescence microscopy, scanning electron microscopy, confocal laser scanning microscopy and amplicon length heterogeneity polymerase chain reaction, have been employed for detection of these communities. Researchers have worked on applications of catheter lock solutions, a fish protein coating, acid shock treatment, susceptibility to bacteriophages, etc., for biofilm control. However, we need to rearrange our strategies to have thorough insight and concentrate on priority basis to develop new accurate, precise and rapid diagnostic protocols for detection and evaluation of biofilm. Above all, the strict compliance to these techniques is required for accurate diagnosis and control.

Primary Shewanella algae Bacteremia Mimicking Vibrio Septicemia

Shewanella algae infections are rare in humans. Previously reported cases of S. algae have mainly been associated with direct contact with seawater. We report a case of primary S. algae bacteremia occurring after the ingestion of raw seafood in a patient with liver cirrhosis that presented a fulminent course of necrotizing fasciitis.

Vibriosis in some fishes: molecular characterization of fish pathogenic vibrios

Studies were undertaken to isolate and characterize vibrio species pathogenic to fish. Thirty six vibrio-like isolates were obtained from twenty one of 160 fish samples. Biochemically the collected isolates were identified as Listonella anguillarum biotype B and C, Vibrio alginolyticus and unidentified lactose-fermenting vibrio spp. Eight vibrio strains of different origins were selected and were grown onto tryptose soya agar with 5% sheep blood for preparation of outer membrane proteins [OMPs]. The OMP profiles of the tested strains were separated using sodium dodecyl- sulphate polyacrylamide gel electrophoresis [SDS- PAGE]. Dice index of similarity was determined with each strain. Analysis of OMPs showed that the local vibrio strains had 8-9 protein bands of molecular weight ranging from 19.7- 212.9 KDa and they contained three major protein bands of molecular weight 19.7, 36 and 80 KDa. Moreover, SDS - PAGE analysis of the local vibrio strains indicated OMP expression differences in protein between strains defined mutant and within the same species strains belonging to different biogroups possessed distinct electrophoretic banding proteins. In conclusion SDS-PAGE analysis of OMPs may be considered as sensitive, reliable and rapid diagnostic method to characterize vibrio isolates

Vibrio vulnificus: un veraneante letal en las aguas oceánicas de Uruguay. Comunicación del primer caso nacional / Vibrio vulnificus: a lethal summer visitor in Uruguay oceanic water. First national case

Vibrio vulnificus es un bacilo Gram-negativo marino causante en el ser humano de dos entidades clínicas bien definidas de acuerdo a la puerta de entrada. Una es la sepsis primaria a través de la ingesta de productos marinos crudos o mal cocidos, especialmente en pacientes inmunocomprometidos. La otra es la infección de partes blandas a través del contacto con el agua de mar de heridas preexistentes o adquiridas en el ambiente marino. Debido a la alta morbimortalidad asociada a este germen, el tratamiento consiste en la prevención, sospecha diagnóstica y antibioticoterapia precoz, debridamiento agresivo de las heridas infectadas y medidas de sostén. Se comunica el primer caso de sepsis por V. vulnificus en Uruguay, al mismo tiempo que se alerta sobre su presencia en sus aguas oceánicas

Sepsis fulminante por Vibrio vulnificus. Serie de casos / Fulminant sepsis related to vibrio vulnificus. series of cases

Introducción. Vibrio vulnificus es un microorganismo marino asociado a infección de heridas, gastroenteritis y sepsis, posterior a la ingesta de mariscos crudos o contacto con agua salada. El principal factor de riesgo es la insuficiencia hepática y la mortalidad varía entre 40 y 63 por ciento. Objetivo. Informar una serie de 8 casos de infección diseminada por V. vulnificus que presentaron sepsis fulminante. Diseño. Serie de casos. Métodos. Se revisó la base de datos del laboratorio de microbiología clínica de 1990 a 1999 del Instituto Nacional de la Nutrición y del Hospital General de Durango, y los expedientes clínicos de los pacientes. Se hizo revisión de la literatura mundial. Resultados. Se encontraron 8 casos de infección por V. vulnificus, todos cursaban con enfermedad hepática crónica, 3 con diabetes mellitus y 1 recibía inmunosupresores. Cinco pacientes habían ingerido mariscos crudos. El tiempo de evolución promedio antes del fallecimiento fue de 4 días. Todos los pacientes cursaron con sepsis, 7 presentaron lesiones cutáneas. Sólo cinco recibieron tratamiento antimicrobiano en las primeras 24 horas, y todos en las primeras 48 horas. Aunque el aislado se reportó sensible, la mortalidad fue del 87.5 por ciento. La sensibilidad antimicrobiana por difusión en disco reportó sensibilidad de 100 por ciento para imipenem, ceftazidima y tetraciclinas; 83 por ciento para cefepime, ticarcilina y cotrimoxazol, y 50 por ciento para quinolonas. Conclusión. La infección por V. vulnificus ocurre en pacientes con insuficiencia hepática crónica y se asocia con una mortalidad elevada. Por ello, esta infección debe sospecharse en pacientes de alto riesgo, con antecedente de ingestión de mariscos y el tratamiento deberá iniciarse lo antes posible.

Vibrio vulnificus infection in Mexico: report of a fatal case

Se informa el segundo caso de infección por Vibrio vulnificus en México. Se describen los tres síndromes clínicos de presentación secundarios a la infección por esta bacteria "marina": gastroenteritis, infección de tejidos blandos y choque séptico, en pacientes con una enfermedad crónica subyacente. Se comentan las estrategias de prevención para la población en riesgo de adquirir esta infección potencialmente letal, que seguramente es poco reconocida en nuestro país.

New pathogens of interest in food Vibrio vulnificus

Essa revisäo aborda os seguintes tópicos relativos a Vibrio vulnificus: características do microorganismo, epidemiologia das infecçöes humanas (septicemia primária, gastroenterites e infecçöes de feridas), mecanismos de virulência (efeito do ferro, papel da citotoxina-hemolisina, papel da capsula na virulência), V. vulnificus em alimentos (casos esporódicos, incidência e sobrevivência em alimentos), métodos de detecçäo em alimentos e medidas de controle

Vibrio fluvialis attachs to but does not enter Hela cell monolayers

Considering the possibility that invasiveness could be a neglected factor of virulence in Vibrio fluvialis-linked enteritis, since a dysenteric form of the disease was seen in Bangladesh, we studied 12 Brazilian strains of the organism, six clinical and six environmental, to determine whether they might be able to enter into HeLa cell monolayers or would carry plasmids incidentally involved in invasiveness. Four human and two environmental isolates attached to but did not enter into the cells. Though five strains harbored plasmids,no relationship was found between the carriage of these genetic elements and adhesiveness

Evaluation of virulence factors in environmental isolates of Vibrio species

Strains of Vibrio parahaemolyticus, Vibrio fluvialis and Vibrio mimicus isolated from seafood and seawater were examined for characteristics related to infectivity, such as enzymatic activity and animal assays. All strains hydrolysed DNA, starch, gelatin and chitin. Variable results were obtained with the haemolysin, chondroitin, collagen, elastin and lecithin tests. Production of thermostable direct haemolysin by V. parahaemolyticus was detected in 7.1 per cent strains derived from seafood and 2 per cent from seawater. In the animal assays, strains of V. fluvialis showed positive results at skin PF (75 per cent ), mouse lethality (100 per cent ), but no fluid accumulation in the suckling mice model was noted. Concerning V. mimicus, results showed skin PF (100 per cent ), mouse lethality (100 per cent ) and fluid accumulation in suckling mice (66.6 per cent )

Laboratory evaluation on pathogenic potentialities of Vibrio furnissii

Sixteen strains of Vibrio furnissii recovered from 16 Brazilian patients with diarrhea were screened for virulence-associated factors. All strains were non-invasive, non-fimbriated, and did not produce either enterotoxins or cholera-like toxin. In contrast, most were hemolytic on blood agar and their broth-culture supernatants damaged HeLa cell monolayers. These cytolysins, as accepted for other enteropathogenic members of the family Vibrionaceae, might be determinants of pathogenicity in V. furnissii-mediated enteritis