Characterization of Vibrio cholerae isolates from 1976 to 2013 in Shandong Province, China

Cholera continues to be a serious public health issue in developing countries. We analyzed the epidemiological data of cholera from 1976 to 2013 in Shandong Province, an eastern coastal area of China. A total of 250 Vibrio cholerae isolates were selected for PCR analysis of virulence genes and pulsed-field gel electrophoresis (PFGE). The analysis of the virulence genes showed that the positive rates for tcpA and tcpI were the highest among strains from the southwest region, which had the highest incidence rate of cholera. Low positive rates for tcpA, tcpI and ctxAB among isolates from after 2000 may be an influencing factor contributing to the contemporary decline in cholera incidence rates. Spatiotemporal serotype shifts (Ogawa, Inaba, Ogawa, Inaba and O139) generally correlated with the variations in the PFGE patterns (PIV, PIIIc, PIa, PIIIb, PIIIa, PIb, and PII). O1 strains from different years or regions also had similar PFGE patterns, while O139 strains exclusively formed one cluster and differed from all other O1 strains. These data indicate that V. cholerae isolates in Shandong Province have continually undergone spatiotemporal changes. The serotype switching between Ogawa and Inaba originated from indigenous strains, while the emergence of serogroup O139 appeared to be unrelated to endemic V. cholerae O1 strains.(AU)

Climate Variability and Avian Cholera Transmission in Guangxi, China

In recent years, Guangxi has become one of the most severely affected provinces by epidemics of avian cholera in China. To date, the major determinant climatic factors of the disease in the region have remained largely unknown, making it difficult to effectively target countermeasures for avian cholera surveillance and control. This study aimed to quantify the relationship between climatic variables and cases of avian cholera in subtropical areas of China. Data relating to local meteorological variables and notified cases of avian cholera were supplied by the relevant authorities between January 2006 and December 2015. Spearman correlation, co-linearity statistics and cross-correlation analysis were applied to the data, controlling for co-linearity and lag effects. A time-series Poisson regression analysis was conducted to examine the degree of correlation between the climate variables and avian cholera transmission. The results indicated that monthly mean temperature, relative humidity, rainfall and the multivariate El Niño Southern Oscillation Index, with 2-3 months lag, were correlated with avian cholera incidence. The final model had good predictive ability for the occurrence of avian cholera. Overall, the findings indicate that climate variability plays an important role in avian cholera transmission in Guangxi province. Adoption of the model presented in this study could usefully inform avian cholera surveillance strategies, making them significantly simpler and more effective. The model could also serve as a decision support tool for veterinary professionals and health authorities.(AU)

Climate Variability and Avian Cholera Transmission in Guangxi, China

In recent years, Guangxi has become one of the most severely affected provinces by epidemics of avian cholera in China. To date, the major determinant climatic factors of the disease in the region have remained largely unknown, making it difficult to effectively target countermeasures for avian cholera surveillance and control. This study aimed to quantify the relationship between climatic variables and cases of avian cholera in subtropical areas of China. Data relating to local meteorological variables and notified cases of avian cholera were supplied by the relevant authorities between January 2006 and December 2015. Spearman correlation, co-linearity statistics and cross-correlation analysis were applied to the data, controlling for co-linearity and lag effects. A time-series Poisson regression analysis was conducted to examine the degree of correlation between the climate variables and avian cholera transmission. The results indicated that monthly mean temperature, relative humidity, rainfall and the multivariate El Niño Southern Oscillation Index, with 2-3 months lag, were correlated with avian cholera incidence. The final model had good predictive ability for the occurrence of avian cholera. Overall, the findings indicate that climate variability plays an important role in avian cholera transmission in Guangxi province. Adoption of the model presented in this study could usefully inform avian cholera surveillance strategies, making them significantly simpler and more effective. The model could also serve as a decision support tool for veterinary professionals and health authorities.

Vibrio spp. pathogenicity factors of importance in foodborne diseases / Fatores de patogenicidade de Vibrio spp. de importância em doenças transmitidas por alimentos

Bacteria of the genus Vibrio typically habitat marine and estuarine environment and are commonly isolated from fish. The main Vibrio species reported as agents of infections in humans are V. vulnificus , V. parahaemolyticus , V. cholerae and V. mimicus . V. vulnificus is considered the most dangerous, may cause sepsis and lead to death. V. parahaemolyticus is an important pathogen in coastal regions of temperate and tropical climates around the world and has been responsible for cases of gastroenteritis associated with consumption of fish, shellfish and marine crustaceans. V. cholerae causes outbreaks, epidemics and pandemics related to estuarine environments. V. mimicus can cause sporadic episodes of acute gastroenteritis and infections. The pathogenicity of the bacteria is linked to the ability of the micro-organism to initiate a disease (including entry, colonization and multiplication in the human body). For this to occur, the micro-organisms make use of several factors. The objective of this review is to summarize the knowledge available in the literature on the factors of pathogenicity of V. vulnificus , V. parahaemolyticus , V. cholerae and V. mimicus.

As bactérias do gênero Vibrio habitam ambiente tipicamente marinho e estuarino, sendo comumente isoladas de pescados. As principais espécies de Vibrio reportadas como agentes de infecções em humanos são V. vulnificus , V. parahaemolyticus , V. cholerae e V. mimicus . V. vulnificus é considerado o mais perigoso, podendo causar septicemia e levar à morte. V. parahaemolyticus é um patógeno importante nas regiões costeiras de clima temperado e tropical em todo o mundo e tem sido responsável por casos de gastroenterites associadas ao consumo de peixes, moluscos e crustáceos marinhos. V. cholerae causa surtos, epidemias e pandemias relacionados com ambientes estuarinos. V. mimicus pode causar episódios esporádicos de gastroenterite aguda e infecções de ouvido. A patogenicidade das bactérias está ligada à habilidade do micro-organismo em iniciar uma doença (incluindo entrada, colonização e multiplicação no corpo humano). Para que isso ocorra, os micro-organismos fazem uso de diversos fatores. O objetivo desta revisão foi sintetizar o conhecimento disponível na literatura sobre os fatores de patogenicidade de V. vulnificus , V. parahaemolyticus , V. cholerae e V. mimicus.

Fatores de patogenicidade de Vibrio spp. de importância em doenças transmitidas por alimentos / Vibrio spp. pathogenicity factors of importance in foodborne diseases

As bactérias do gênero Vibrio habitam ambiente tipicamente marinho e estuarino, sendo comumente isoladas de pescados. As principais espécies de Vibrio reportadas como agentes de infecções em humanos são V. vulnificus , V. parahaemolyticus , V. cholerae e V. mimicus . V. vulnificus é considerado o mais perigoso, podendo causar septicemia e levar à morte. V. parahaemolyticus é um patógeno importante nas regiões costeiras de clima temperado e tropical em todo o mundo e tem sido responsável por casos de gastroenterites associadas ao consumo de peixes, moluscos e crustáceos marinhos. V. cholerae causa surtos, epidemias e pandemias relacionados com ambientes estuarinos. V. mimicus pode causar episódios esporádicos de gastroenterite aguda e infecções de ouvido. A patogenicidade das bactérias está ligada à habilidade do micro-organismo em iniciar uma doença (incluindo entrada, colonização e multiplicação no corpo humano). Para que isso ocorra, os micro-organismos fazem uso de diversos fatores. O objetivo desta revisão foi sintetizar o conhecimento disponível na literatura sobre os fatores de patogenicidade de V. vulnificus , V. parahaemolyticus , V. cholerae e V. mimicus.(AU)

Bacteria of the genus Vibrio typically habitat marine and estuarine environment and are commonly isolated from fish. The main Vibrio species reported as agents of infections in humans are V. vulnificus , V. parahaemolyticus , V. cholerae and V. mimicus . V. vulnificus is considered the most dangerous, may cause sepsis and lead to death. V. parahaemolyticus is an important pathogen in coastal regions of temperate and tropical climates around the world and has been responsible for cases of gastroenteritis associated with consumption of fish, shellfish and marine crustaceans. V. cholerae causes outbreaks, epidemics and pandemics related to estuarine environments. V. mimicus can cause sporadic episodes of acute gastroenteritis and infections. The pathogenicity of the bacteria is linked to the ability of the micro-organism to initiate a disease (including entry, colonization and multiplication in the human body). For this to occur, the micro-organisms make use of several factors. The objective of this review is to summarize the knowledge available in the literature on the factors of pathogenicity of V. vulnificus , V. parahaemolyticus , V. cholerae and V. mimicus.(AU)

Vibrio spp. pathogenicity factors of importance in foodborne diseases / Fatores de patogenicidade de Vibrio spp. de importância em doenças transmitidas por alimentos

Bacteria of the genus Vibrio typically habitat marine and estuarine environment and are commonly isolated from fish. The main Vibrio species reported as agents of infections in humans are V. vulnificus , V. parahaemolyticus , V. cholerae and V. mimicus . V. vulnificus is considered the most dangerous, may cause sepsis and lead to death. V. parahaemolyticus is an important pathogen in coastal regions of temperate and tropical climates around the world and has been responsible for cases of gastroenteritis associated with consumption of fish, shellfish and marine crustaceans. V. cholerae causes outbreaks, epidemics and pandemics related to estuarine environments. V. mimicus can cause sporadic episodes of acute gastroenteritis and infections. The pathogenicity of the bacteria is linked to the ability of the micro-organism to initiate a disease (including entry, colonization and multiplication in the human body). For this to occur, the micro-organisms make use of several factors. The objective of this review is to summarize the knowledge available in the literature on the factors of pathogenicity of V. vulnificus , V. parahaemolyticus , V. cholerae and V. mimicus.(AU)

As bactérias do gênero Vibrio habitam ambiente tipicamente marinho e estuarino, sendo comumente isoladas de pescados. As principais espécies de Vibrio reportadas como agentes de infecções em humanos são V. vulnificus , V. parahaemolyticus , V. cholerae e V. mimicus . V. vulnificus é considerado o mais perigoso, podendo causar septicemia e levar à morte. V. parahaemolyticus é um patógeno importante nas regiões costeiras de clima temperado e tropical em todo o mundo e tem sido responsável por casos de gastroenterites associadas ao consumo de peixes, moluscos e crustáceos marinhos. V. cholerae causa surtos, epidemias e pandemias relacionados com ambientes estuarinos. V. mimicus pode causar episódios esporádicos de gastroenterite aguda e infecções de ouvido. A patogenicidade das bactérias está ligada à habilidade do micro-organismo em iniciar uma doença (incluindo entrada, colonização e multiplicação no corpo humano). Para que isso ocorra, os micro-organismos fazem uso de diversos fatores. O objetivo desta revisão foi sintetizar o conhecimento disponível na literatura sobre os fatores de patogenicidade de V. vulnificus , V. parahaemolyticus , V. cholerae e V. mimicus.(AU)

Establishment of a Pathogenicity Index for One-day-old Broilers to Pasteurella multocida Strains Isolated from Clinical Cases in Poultry and Swine

Although Pasteurella multocida is a member of the respiratory microbiota, under some circumstances, it is a primary agent of diseases , such as fowl cholera (FC), that cause significant economic losses. Experimental inoculations can be employed to evaluate the pathogenicity of strains, but the results are usually subjective and knowledge on the pathogenesis of this agent is still limited. The objective of this study was to establish a new methodology for classifying the pathogenicity of P. multocida by formulating a standard index. Strains isolated from FC cases and from swine with respiratory problems were selected. One hundred mL of a bacterial culture of each strain, containing 106 CFU, was inoculated in 10 one-day-old broilers. Mortality after inoculation, time of death (TD), and the presence of six macroscopic lesions were evaluated over a period of seven days post-inoculation (dpi). A Pathogenicity Index Per Bird (IPI), ranging 0 to 10, was calculated. Liver and heart fragments were collected to reisolate the bacteria. Blood was collected from the surviving birds, and an ELISA test was carried out to detect specific antibodies. The median of the pathogenicity indices, the number of lesions and the rate of bacteria reisolation were significantly different (p 0.05) among the origins of the isolates (p 0.05). The pathogenicity index developed in this study allows the classification of Pasteurella multocida pathogenicity and may be an alternative to the pathogenicity models currently used for screening.

Establishment of a Pathogenicity Index for One-day-old Broilers to Pasteurella multocida Strains Isolated from Clinical Cases in Poultry and Swine

Although Pasteurella multocida is a member of the respiratory microbiota, under some circumstances, it is a primary agent of diseases , such as fowl cholera (FC), that cause significant economic losses. Experimental inoculations can be employed to evaluate the pathogenicity of strains, but the results are usually subjective and knowledge on the pathogenesis of this agent is still limited. The objective of this study was to establish a new methodology for classifying the pathogenicity of P. multocida by formulating a standard index. Strains isolated from FC cases and from swine with respiratory problems were selected. One hundred mL of a bacterial culture of each strain, containing 106 CFU, was inoculated in 10 one-day-old broilers. Mortality after inoculation, time of death (TD), and the presence of six macroscopic lesions were evaluated over a period of seven days post-inoculation (dpi). A Pathogenicity Index Per Bird (IPI), ranging 0 to 10, was calculated. Liver and heart fragments were collected to reisolate the bacteria. Blood was collected from the surviving birds, and an ELISA test was carried out to detect specific antibodies. The median of the pathogenicity indices, the number of lesions and the rate of bacteria reisolation were significantly different (p 0.05) among the origins of the isolates (p 0.05). The pathogenicity index developed in this study allows the classification of Pasteurella multocida pathogenicity and may be an alternative to the pathogenicity models currently used for screening.(AU)

Diversidade genética de receptores de lactoferrina e transferrina em Moraxella bovis e Moraxella bovoculi

A ceratoconjuntivite infecciosa bovina (CIB) é a doença ocular de maior relevância em bovinos e os principais agentes etiológicos associados são Moraxella bovis e Moraxella bovoculi. Para o controle desta doença a vacinação é imprescindível, entretanto, as vacinas atualmente disponíveis apresentam baixa eficiência. Espécies de Moraxella possuem sistemas capazes de extrair ferro a partir de glicoproteínas compostos por uma proteína integral da membrana externa, as proteínas de ligação à lactoferrina ou transferrina A (LbpA ou TbpA), e uma lipoproteína de superfície, as proteínas de ligação à lactoferrina ou transferrina B (LbpB ou TbpB). Imunização com antígenos derivados desses receptores demonstraram grande capacidade em prevenir infecções, porém, não existem estudos sobre a diversidade genética desses receptores e tampouco foram investigados como potenciais compostos vacinais. Neste contexto, esta tese foi elaborada visando investigar a diversidade genética das proteínas TbpA e TbpB de M. bovis e M. bovoculi (manuscrito 1) e a diversidade genética de LbpA e o desenvolvimento de antígenos híbridos (manuscrito 2). Para o manuscrito 1, 37 sequências de M. bovis e M. bovoculi foram utilizadas, sendo traduzidas para aminoácidos e alinhadas. Posteriormente, árvores filogenéticas foram geradas, e os alinhamentos mapeados nas estruturas preditas das proteínas. As sequências de TbpB foram separadas por espécies e mostraram-se mais variáveis que as de TbpA. Também, foram selecionadas duas cepas representativas de TbpB que provavelmente são capazes de cobrir toda a variabilidade encontrada nessas cepas. No manuscrito 2, análise semelhante foi realizada com trinta e seis sequências de LbpA, além disso, foram construídos cinco antígenos híbridos utilizando quatro combinações diferentes dos loops de LbpA em um esqueleto da lipoproteína de superfície de Vibrio cholerae (VcSLP). LbpA mostrou-se bastante conservada, inclusive em toda sua estrutura. Os antígenos híbridos foram expressos em pequena escala de forma eficiente e apresentaram potencial para serem produzidos em grande escala e analisados como antígenos vacinais. Em conclusão, foi demonstrado em dois estudos diferentes a diversidade de TbpA, TbpB e LbpA e as abordagens que podem ser feitas para produzir antígenos vacinais a partir destas proteínas pensando em abranger toda diversidade genética destes receptores em ambas as espécies.

Infectious bovine keratoconjunctivitis (IBK) is the most important eye disease in cattle, which has a great economic impact due to eye injuries and loss of vision, resulting in pain, reduced milk production, and decreased weight gain. The main etiological agents associated with IBK are Moraxella bovis (M. bovis) and Moraxella bovoculi (M. bovoculi). Vaccination is essential for the disease control; however, currently available vaccines may present limited efficiency. Moraxella spp. have systems capable of extracting iron from the host glycoproteins named lactoferrin and transferrin. Each receptor is composed of an integral outer membrane protein, named lactoferrin or transferrin binding protein A (LbpA or TbpA), and of exposed surface lipoprotein, named lactoferrin or transferrin binding protein B (LbpB or TbpB). These receptors are known to be functionally and genetically related and are known for being essential in the maintenance of pathogens on the mucosal surface leading to disease development. Studies involving immunization with antigens derived from these receptors demonstrate a great capacity to prevent infection, as well as to eliminate colonization of the upper respiratory tract. A great potential of these receptors as vaccine antigens is expected due to their privileged position on the cell surface, and their presumed ubiquity in all isolates of Moraxella spp. However, to date, there have been no studies on the diversity of the pathogens responsible for IBK, or they have been investigated as potential vaccine compounds. In this context, this thesis was designed to investigate the genetic diversity and its distribution in the structure of TbpA and TbpB proteins of M. bovis and M. bovoculi (manuscript 1) and the diversity of LbpA, as well as the development of hybrid antigens (manuscript 2). For manuscript 1, DNA sequences of thirty-seven M. bovis and M. bovoculi strains were translated into amino acids to build phylogenetic trees for each protein. The alignments were then mapped on the predicted structures of the proteins. In the phylogenetic analysis, TbpB sequences were separated by species and more variable than TbpA. Also, two representative strains of TbpB were selected that are likely to be able to cover all the variability found in these strains. In manuscript 2, a similar analysis was performed with thirty-six LbpA sequences, and five hybrid antigens were constructed using four different combinations of LbpA loops in a scaffold of the surface lipoprotein from Vibrio cholerae (VcSLP). LbpA was very conserved also throughout its whole structure. Hybrid antigens were expressed on a small scale efficiently and had the potential to be large scaled for analysis of immunogenicity and cross-reactivity as vaccine antigens. In conclusion, it was demonstrated in two different studies the diversity of TbpA, TbpB, and LbpA and the approaches that can be taken to produce vaccine antigens derived from these proteins intending to cover all the genetic diversity of the species

Antibacterial potential of a basic phospholipase A2(VRV-PL-VIIIa) from Daboia russelii pulchella (Russell's viper) venom

Background:Microbial/bacterial resistance against antibiotics poses a serious threat to public health. Furthermore, the side effects of these antibiotics have stimulated tremendous interest in developing new molecules from diverse organisms as therapeutic agents. This study evaluates the antibacterial potential of a basic protein, Vipera russellii venom phospholipase A2 fraction VIIIa (VRV-PL-VIIIa), from Daboia russelii pulchella venom against gram-positive and gram-negative bacteria.Methods:The antibacterial potential of VRV-PL-VIIIa in the presence and absence of an inhibitor (p-bromophenacyl bromide) was tested against gram-positive and gram-negative bacteria and the minimum inhibitory concentration was determined by microdilution tests.Results:VRV-PL-VIIIa demonstrated potent antibacterial activities against all the human pathogenic strains tested. It more effectively inhibited such gram-positive bacteria as Staphylococcus aureus and Bacillus subtilis, when compared to the gram-negative bacteria Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae and Salmonella paratyphi. It inhibited bacterial growth at minimum inhibitory concentration values ranging from 11.1 to 19.2 μg/mL. The anti-bacterial potential of VRV-PL-VIIIa was comparable to the standards gentamycin, chlorophenicol and streptomycin. The PLA2's hemolytic and antibacterial activities were strongly correlated. Furthermore, even in the presence of p-bromophenacyl bromide, intense antibacterial activity was observed, suggesting a dissociation or partial overlapping of the bactericidal/antimicrobial domains.Conclusion:VRV-PL-VIIIa demonstrated potent antibacterial activities against all the human pathogenic strains tested. The study shows that despite a strong correlation between enzymatic and antimicrobial activities of VRV-PL-VIIIa, it may possess additional properties that mimic the bactericidal/membrane permeability-increasing protein. This study encourages further in-depth studies on the molecular mechanisms of antibacterial properties of VRV-PL-VIIIa, which would thereby facilitate development of this protein into a possible therapeutic lead molecule for treating bacterial infections.(AU)

Antibacterial potential of a basic phospholipase A (VRV-PL-VIIIa) from Daboia russelii pulchella (Russell's viper) venom

Background: Microbial/bacterial resistance against antibiotics poses a serious threat to public health. Furthermore, the side effects of these antibiotics have stimulated tremendous interest in developing new molecules from diverse organisms as therapeutic agents. This study evaluates the antibacterial potential of a basic protein, Vipera russellii venom phospholipase A2 fraction VIIIa (VRV-PL-VIIIa), from Daboia russelii pulchella venom against gram-positive and gram-negative bacteria. Methods: The antibacterial potential of VRV-PL-VIIIa in the presence and absence of an inhibitor (p-bromophenacyl bromide) was tested against gram-positive and gram-negative bacteria and the minimum inhibitory concentration was determined by microdilution tests. Results: VRV-PL-VIIIa demonstrated potent antibacterial activities against all the human pathogenic strains tested. It more effectively inhibited such gram-positive bacteria as Staphylococcus aureus and Bacillus subtilis, when compared to the gram-negative bacteria Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae and Salmonella paratyphi. It inhibited bacterial growth at minimum inhibitory concentration values ranging from 11.1 to 19.2 μg/mL. The anti-bacterial potential of VRV-PL-VIIIa was comparable to the standards gentamycin, chlorophenicol and streptomycin. The PLA2's hemolytic and antibacterial activities were strongly correlated. Furthermore, even in the presence of p-bromophenacyl bromide, intense antibacterial activity was observed, suggesting a dissociation or partial overlapping of the bactericidal/antimicrobial domains. Conclusion: VRV-PL-VIIIa demonstrated potent antibacterial activities against all the human pathogenic strains tested. The study shows that despite a strong correlation between enzymatic and antimicrobial activities of VRV-PL-VIIIa, it may possess additional properties that mimic the bactericidal/membrane permeability-increasing protein. This study encourages further in-depth studies on the molecular mechanisms of antibacterial properties of VRV-PL-VIIIa, which would thereby facilitate development of this protein into a possible therapeutic lead molecule for treating bacterial infections.(AU)

Antibacterial potential of a basic phospholipase A (VRV-PL-VIIIa) from Daboia russelii pulchella (Russell's viper) venom

Background: Microbial/bacterial resistance against antibiotics poses a serious threat to public health. Furthermore, the side effects of these antibiotics have stimulated tremendous interest in developing new molecules from diverse organisms as therapeutic agents. This study evaluates the antibacterial potential of a basic protein, Vipera russellii venom phospholipase A2 fraction VIIIa (VRV-PL-VIIIa), from Daboia russelii pulchella venom against gram-positive and gram-negative bacteria. Methods: The antibacterial potential of VRV-PL-VIIIa in the presence and absence of an inhibitor (p-bromophenacyl bromide) was tested against gram-positive and gram-negative bacteria and the minimum inhibitory concentration was determined by microdilution tests. Results: VRV-PL-VIIIa demonstrated potent antibacterial activities against all the human pathogenic strains tested. It more effectively inhibited such gram-positive bacteria as Staphylococcus aureus and Bacillus subtilis, when compared to the gram-negative bacteria Escherichia coli, Vibrio cholerae, Klebsiella pneumoniae and Salmonella paratyphi. It inhibited bacterial growth at minimum inhibitory concentration values ranging from 11.1 to 19.2 μg/mL. The anti-bacterial potential of VRV-PL-VIIIa was comparable to the standards gentamycin, chlorophenicol and streptomycin. The PLA2's hemolytic and antibacterial activities were strongly correlated. Furthermore, even in the presence of p-bromophenacyl bromide, intense antibacterial activity was observed, suggesting a dissociation or partial overlapping of the bactericidal/antimicrobial domains. Conclusion: VRV-PL-VIIIa demonstrated potent antibacterial activities against all the human pathogenic strains tested. The study shows that despite a strong correlation between enzymatic and antimicrobial activities of VRV-PL-VIIIa, it may possess additional properties that mimic the bactericidal/membrane permeability-increasing protein. This study encourages further in-depth studies on the molecular mechanisms of antibacterial properties of VRV-PL-VIIIa, which would thereby facilitate development of this protein into a possible therapeutic lead molecule for treating bacterial infections.

Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

Vibrio cholerae O1 from superficial water of the Tucunduba Stream, Brazilian Amazon

Isolation and genetic characterization of an environmental Vibrio cholerae O1 from the Amazon is reported. This strain lacks two major virulence factors - CTX and TCP - but carries other genes related to virulence. Genetic similarity with epidemic strains is evaluated and the importance of V. cholerae surveillance in the Amazon is emphasized.

Vibrio cholerae O1 from superficial water of the Tucunduba Stream, Brazilian Amazon

Isolation and genetic characterization of an environmental Vibrio cholerae O1 from the Amazon is reported. This strain lacks two major virulence factors - CTX and TCP - but carries other genes related to virulence. Genetic similarity with epidemic strains is evaluated and the importance of V. cholerae surveillance in the Amazon is emphasized.

UTILIZAÇÃO DE EXTRATOS DE MACROALGAS NO REVESTIMENTO DE FILÉS DE ROBALO CONGELADO E RESFRIADO

Este trabalho visou analisar o efeito antimicrobiano e antioxidante de extratos de macroalgas, para conservar filés de robalo como alternativa ao uso de aditivos sintéticos. Espécies de macroalgas foram coletadas no banco natural da praia de Manguinhos, Itaparica BA e, encaminhadas sob refrigeração para a Universidade Federal do Recôncavo da Bahia para triagem, identificação e herborização, secagem em estufa (40ºC), moagem e extração com etanol por meio da maceração a frio por 72 h. A atividade antimicrobiana foi determinada pela concentração inibitória mínima (CIM), frente a Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 43300, Salmonella enterica sorotipo Enteritides ATCC13076, Vibrio cholerae, Bacillus cereus, Listeria monocytogenes CERELA e Enterococcus faecalis. Para verificar a atividade antimicrobiana na matriz alimentar utilizou-se filés revestidos com alginato de sódio a 1% adicionado do extrato da macroalga, os tratamentos foram mantidos sob refrigeração por um período de 10 dias, sendo realizadas análises microbiológicas nos dias 1, 3, 5, 7 e 10 em triplicata. Foram analisadas a atividade antioxidante dos extratos usando os métodos DPPH (2,2-difenil-1-picrilhidrazilo) e ABTS [2,2-azinobis-(3-etilbenzotiazolina-6-ácido sulfônico)], teor de flavonoides, tanino esteroides/triterpenoide, saponina e alcaloides. A solução de revestimento foi obtida usando alginato de sódio a 1% + 20 mg.mL-1 do extrato de P. gymnospora. O monitoramento microbiológico e físico-químico foi realizado nos intervalos T0, T30, T60, T90 e T120 dias. Ao final foi realizada análise sensorial para verificar se o extrato da macroalga influenciava no grau de aceitação dos filés de peixe. Os peixes foram adquiridos no município de Canavieiras-BA e encaminhados em caixas isotérmicas para UFRB onde foram processados. Dentre os microrganismos testados na CIM S. aureus se mostrou o mais sensível ao ser inibido por quatro extratos, tendo P. gymnospora apresentado maior inibição. Todos os extratos testados apresentaram efeito bacteriostático. Na matriz alimentar, houve redução da população microbiana de 3 ciclos logaritmos para L.monocytoges (24 h) e para S. aureus (72 h). Os ensaios químicos DPPH e ABTS mostraram que todos os extratos analisados apresentaram biocompostos com capacidade de sequestrar radicais livres, sendo que foi P. gymnospora que apresentou maior atividade antioxidante, conteúdo de compostos fenólicos e compostos fitoquímicos identificados. Durante 120 dias de armazenamento o extrato da P. gymnospora apresentou potencial semelhante ao aditivo químico BHT. Estes resultados evidenciam que o extrato etanólico de P. gymnospora pode ser utilizado como alternativa ao uso de aditivos sintéticos quanto a atividade antioxidante.

This work aimed to analyze the antimicrobial and antioxidant effects of seaweed extracts to preserve fillet of robalo as an alternative to the use of synthetic additives. Species of seaweed were collected at the natural bank of the beach of Manguinhos, Itaparica, Bahia, and sent to the Federal University of the Recôncavo da Bahia for sorting, identification and herborization, drying in a greenhouse (40ºC), grinding and ethanol extraction of cold maceration for 72 h. The antimicrobial activity was determined by the minimum inhibitory concentration (MIC) against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 43300, Salmonella enterica serotype Enteritides ATCC13076, Vibrio cholerae, Bacillus cereus, Listeria monocytogenes CERELA and Enterococcus faecalis. In order to verify the antimicrobial activity in the food matrix, fillets coated with 1% sodium alginate added to the seaweed extract were used, the treatments were kept under refrigeration for a period of 10 days, and microbiological tests were performed on days 1, 3, 5 , 7 and 10 in triplicate. The antioxidant activity of the extracts was analyzed using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2'-azinobis- (3-ethylbenzothiazoline-6-sulfonic acid)], flavonoid content, tannin steroids / triterpenoid, saponin and alkaloids. The coating solution was obtained using 1% sodium alginate + 20 mg.mL-1 extract of P. gymnospora. Microbiological and physicochemical monitoring was performed at intervals T0, T30, T60, T90 and T120 days. At the end, sensorial analysis was carried out to verify if the extract of the seaweed influenced the degree of acceptance of the fish fillets. The fish were purchased in the municipality of Canavieiras-BA and sent in isothermal boxes to UFRB where they were processed. Among the microorganisms tested in MIC S. aureus showed the most sensitive to be inhibited by four extracts, with P. gymnospora presented greater inhibition. All extracts tested had a bacteriostatic effect. In the food matrix, there was a reduction of the microbial population of 3 logarithmic cycles for L. monocytoges (24 h) and for S. aureus (72 h). The chemical tests DPPH and ABTS showed that all the analyzed extracts presented biocomposites with capacity to sequester free radicals, being that P. gymnospora that presented greater antioxidant activity, content of phenolic compounds and identified phytochemical compounds. During 120 days of storage the extract of P. gymnospora showed similar potential to the chemical additive BHT. These results show that the ethanolic extract of P. gymnospora can be used as an alternative to the use of synthetic additives for antioxidant activity.

Isolamento de Vibrio spp de camarões comercializados in natura na cidade de São Gonçalo - RJ

Bactérias do gênero Vibrio fazem parte da microbiota de camarões, pois têm capacidade de associar-se à quitina presente no exoesqueleto destes animais e ao zooplancton, que por sua vez são consumidos por estes animais. O gênero contém pelo menos 12 espécies patogênicas, incluindo V. cholerae, responsável por várias pandemias de cólera. A contaminação humana acontece através do consumo de alimentos, principalmente de origem marinha, crus ou mal cozidos. Por se tratar de um tipo de pescado amplamente consumido pela população, este trabalho teve como objetivo investigar a presença de espécies de Vibrio em camarões comercializados in natura na cidade de São Gonçalo-RJ. Os camarões foram adquiridos em duas peixarias da cidade e caracterizados por metodologia convencional e molecular; cento e vinte e nove amostras testaram positivamente para as provas bioquímicas realizadas e, destas, cinquenta e duas testaram positivamente para os testes moleculares. Visando investigar a identidade das espécies de Vibrio, as amostras foram submetidas ao PCR multiplex para 4 espécies (V. cholerae, V. mimicus, V. parahaemolyticus, V. vulnificus). Doze isolados foram identificados como V parahaemolyticus e 9 como V. cholerae não O1. Dentre os demais isolados, 31 demonstram se tratar de outras espécies de Vibrio spp. O Sítio com o maior número de isolados foi a casca, seguida pelo hepatopâncreas/ hemolinfa. A ribotipagem por PCR das 21 cepas demonstrou claramente a separação das cepas de V. parahaemolyticus e V. cholerae. As cepas de V. cholerae e V. parahaemolyticus demonstraram alto índice de resistência a ampicilina (83,33%) e 100% de sensibilidade à nitroflurantoína e tetraciclina. Sete cepas (38,8%) apresentaram perfil de multirresistência a dois antimicrobianos. Nossos resultados demonstram a presença de espécies patogênicas de Vibrio em amostras de pescados amplamente consumidos pela população. (AU)

Vibrio genus is part of the microbiota of shrimps as they have the ability to join the chitin present in the exoskeleton of these animals and to zooplancton, which are consumed by shrimp. The genus contains at least 12 pathogenic species, which includes V. cholerae, responsible for several pandemics of cholera. Human contamination occurs through the consumption of raw or undercooked seafood. Considering it is a type of fish widely consumed by the population, this study aims to investigate the presence of species of Vibrio in shrimps commercialized in São Gonçalo/RJ Shrimps were acquired in two local fishmarkets and characterized by conventional and molecular methods. One hundred and twenty nine isolates tested positive in the biochemical tests. Among them, fifty two have tested positive in molecular tests. In order to investigate the identity of the species of Vibrio, the samples were subjected to the multiplex PCR searching for four species of Vibrio (V. cholerae, V. mimicus, v. parahaemolyticus, V. vulnificus). Twelve isolates were identified as V. parahaemolyticus and 9 as V. cholera non-O1. Thirty one were classified as Vibrio spp. The site with the largest number of isolates was the shell, followed by the hepatopancreas/hemolymph. The PCR ribotyping clearly separate V. parahaemolyticus strains from V. cholerae strains. The strains of V. cholerae and V. parahaemolyticus showed high ampicillin resistance index (83.33%) and 100% sensitivity to nitrofurantoin and tetracycline. Seven strains (38.8%) had profiles of multiresistence to two antimicrobials. Our results demonstrate the presence of pathogenic species of Vibrio in shrimp samples widely consumed by the population.(AU)

Vibrio na água e sedimento de viveiros de quatro fazendas de carcinicultura no estado do Ceará, Brasil / Vibrio in pond water and sediment from four shrimp farms in Ceará state, Brazil

Foram realizadas 16 coletas, oito no período chuvoso e oito no período de estio, em quatro fazendas de carcinicultura do Estado do Ceará, nos estuários dos rios Jaguaribe (fazendas A e B) e Acaraú (fazendas C e D), totalizando 32 amostras. O objetivo da pesquisa foi quantificar e identificar Vibrio spp. nas amostras de água e sedimento. Os valores máximos da Contagem Padrão em Placas (CPP) de Vibrio spp. encontrados para as amostras de água, no período chuvoso, foram de 5.103 UFC/mL est. e, para o sedimento, de 7,5.103 UFC/g est. No período de estio, a CPP máxima para água foi de 4,35.102 UFC/mL est. e de 3,55.103 UFC/g est. para as amostras de sedimento. Foram obtidos 36 isolados de Vibrio: Vibrio spp. (17), V. vulnificus B1(3); V. calviensis (2), V. cholerae (2), V. litoralis (2), V. metschnikovii (2), V. agarivorans (1), V. alginolyticus (1), V. campbellii (1), V. coralliilyticus (1), V. diazotrophicus (1), V. logei (1), V. mediterranei (1), V. vulnificus B2 (1). O conhecimento da presença de espécies, nunca anteriormente isoladas em viveiros de fazendas de carcinicultura, tais como o V. coralliilyticus, V. agarivorans, V. litoralis e V. calviensis são importantes para o monitoramento microbiológico contínuo desses ambientes. (AU)

Sixteen collections were taken, eight during rainy season and eight on the draught season in four shrimp farms in Ceará State, from Jaguaribe River (farms A and B) and Acaraú River (farms C and D) estuaries, totalizing 32 samples. The goal of the research was to identify and quantify Vibrio spp. in water and in sediment samples. The maximum Standard Plate Count (SPC) values of Vibrio spp. calculated for the rainy season, from water, was 5.103 CFU/mL est., and for the sediment 7.5.103 CFU/g est.. For the draught season, maximum counting for water was 4.35.102 CFU/mL est. and for sediment 3.55.103 CFU/g est.. Thirty six strains of Vibrio were isolated: Vibrio spp. (17), V. vulnificus B1(3), V. calviensis (2), V. cholerae (2), V. litoralis (2), V. metschnikovii (2), V. agarivorans (1), V. alginolyticus (1), V. campbellii (1), V. coralliilyticus (1), V. diazotrophicus (1), V. logei (1), V. mediterranei (1), V. vulnificus B2 (1). The isolation of species never previously isolated of shrimp farms, such as V. coralliilyticus, V. agarivorans, V. litoralis and V. calviensis are important for the continuous microbiological monitoring these environments. (AU)

Atividade antimicrobiana de Lactobacillus reuteri contra bactérias de interesse alimentar / Antimicrobial activity of Lactobacillus reuteri against bacteria of nourishment concern

Lactobacillus reuteri é uma espécie heterofermentativa que reside nos tratos gastrointestinal (GI), vaginale oral do homem e de outros animais de sangue quente. A ação probiótica de L. reuteri é atribuída a sua capacidade de exercer um efeito inibitório sobre micro-organismos patogênicos pela combinação de diversos mecanismos, incluindo-se a produção de ácido lático, peróxido de hidrogênio e produção de bacteriocinas. A reuterina é um composto neutro, de baixo peso molecular, solúvel em água, ativa em uma larga faixa de pH e resistente a ação de enzimas proteolíticas e lipolíticas. Neste estudo foi avaliado o efeito inibitório de L. reuteri sobre bactérias patogênicas ou deteriorantes de alimentos. L. reuteri apresentou capacidadede inibir o crescimento de Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus e Vibrio cholerae. Sugere-se que o antimicrobiano produzido pelo L. reuteri seja a reuterina.

Lactobacillus reuteri is a heterofermentative species that lives in the gastrointestinal (GI), vaginal and oraltracts of humans and other warm-blooded animals. The action of probiotic L. reuteri is derived from itsability to exert an inhibitory effect on pathogens, combining several mechanisms, including the productionof lactic acid, hydrogen peroxide and bacteriocin production. The reuterin is a neutral compound of lowmolecular weight, water soluble, active in a wide pH range, and resistant to proteolytic and lipolytic enzymes.This study evaluated the inhibitory effect of L. reuteri on pathogenic bacteria or food deterioration. L. reuterishowed ability to inhibit the growth of Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteusvulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus and Vibrio cholerae. Itis suggested that the antibiotic produced by L. reuteri is the reuterin.Key words. reuterin, L. reuteri, antimicrobial activity.

Atividade antimicrobiana de Lactobacillus reuteri contra bactérias de interesse alimentar / Antimicrobial activity of Lactobacillus reuteri against bacteria of nourishment concern

Lactobacillus reuteri é uma espécie heterofermentativa que reside nos tratos gastrointestinal (GI), vaginale oral do homem e de outros animais de sangue quente. A ação probiótica de L. reuteri é atribuída a sua capacidade de exercer um efeito inibitório sobre micro-organismos patogênicos pela combinação de diversos mecanismos, incluindo-se a produção de ácido lático, peróxido de hidrogênio e produção de bacteriocinas. A reuterina é um composto neutro, de baixo peso molecular, solúvel em água, ativa em uma larga faixa de pH e resistente a ação de enzimas proteolíticas e lipolíticas. Neste estudo foi avaliado o efeito inibitório de L. reuteri sobre bactérias patogênicas ou deteriorantes de alimentos. L. reuteri apresentou capacidadede inibir o crescimento de Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus e Vibrio cholerae. Sugere-se que o antimicrobiano produzido pelo L. reuteri seja a reuterina.(AU)

Lactobacillus reuteri is a heterofermentative species that lives in the gastrointestinal (GI), vaginal and oraltracts of humans and other warm-blooded animals. The action of probiotic L. reuteri is derived from itsability to exert an inhibitory effect on pathogens, combining several mechanisms, including the productionof lactic acid, hydrogen peroxide and bacteriocin production. The reuterin is a neutral compound of lowmolecular weight, water soluble, active in a wide pH range, and resistant to proteolytic and lipolytic enzymes.This study evaluated the inhibitory effect of L. reuteri on pathogenic bacteria or food deterioration. L. reuterishowed ability to inhibit the growth of Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Proteusvulgaris, Pseudomonas aeruginosa, Salmonella tiphymurium, Staphylococcus aureus and Vibrio cholerae. Itis suggested that the antibiotic produced by L. reuteri is the reuterin.Key words. reuterin, L. reuteri, antimicrobial activity.(AU)