Biofloc production in activated sludge system treating shrimp farming effluent / Produção de bioflocos em sistema de lodos ativados tratando efluente de carcinicultura

ABSTRACT The release of wastewater and the shrimp feed cost are the main challenges faced by the shrimp farming industry. An alternative solution to both problems is biofloc production in a unit external to the farm, in an activated sludge system for effluent treatment. The treatment system's influent was composed of the shrimp farm wastewater supplemented with urea and sugarcane molasses. The results show that the average removal of chemical oxygen demand was 71% and the average biofloc production in the reactor was approximately 1.5g.L-1. Adding molasses to the influent contributed to the increase in the quantity and diversity of existing microorganisms that are beneficial to cultured shrimp. The mass balance of nitrogen compounds confirmed that nitrification occurred in the system. Therefore, the use of the activated sludge system is a viable and environmentally suitable alternative to produce bioflocs and shrimp farming effluent treatment.

RESUMO A geração de efluentes e o custo com a alimentação do camarão são os principais desafios enfrentados pela carcinicultura. Uma solução conjunta para ambos os problemas é a produção de bioflocos em um sistema de lodo ativado para tratamento de efluentes. Neste trabalho, o afluente ao sistema estudado era composto pelas águas residuais do cultivo de camarão suplementadas com ureia e melaço de cana-de-açúcar. Os resultados mostraram que a remoção média de demanda química de oxigênio foi de 71% e a produção média de bioflocos no reator foi de aproximadamente 1,5 g.L-1. A adição de melaço ao afluente contribuiu para o aumento da quantidade e da diversidade de microrganismos benéficos para a produção de camarão. Houve remoção de amônia e nitrificação confirmada pelo balanço de massa. Portanto, a utilização do sistema de lodos ativados é uma alternativa viável e ambientalmente adequada para produzir bioflocos e tratar efluentes de cultivo de camarão.

Antimicrobial resistance and potential virulence of Vibrio parahaemolyticus isolated from water and bivalve mollusks from Bahia, Brazil.

The aim of the present study was to verify the antimicrobial susceptibility profile and virulence factors of Vibrio parahaemolyticus isolated from water and bivalve mollusks. A high percentage of V. parahaemolyticus was isolated in natura, processed bivalves tissues, and surrounding water (75%, 20%, and 59%, respectively). The most potential virulence phenotype in V. parahaemolyticus isolates was amylase production (97%) followed by DNase (83%), phospholipase (70%), ß-hemolytic activity (57%). The tdh and trh genes were not detected. Besides, a high antimicrobial resistance was observed for ampicillin (97%), minimum inhibitory concentration [MIC] = 400 µg and cephalothin (93%, MIC ≤ 100 µg). The absence of expression of tdh and trh virulence genes excluded the toxigenic potential of V. parahaemolyticus isolates; however, the high prevalence of antimicrobial resistance among the environmental strains is a risk to human health.

Antibacterial and cytotoxicity activity in macroalgae extracts: perspectives for the use against pathogenic bacteria from shrimp farms (Litopenaeus vannamei) / Atividade antibacteriana e citotóxica em extratos de macroalgas: perspectivas de uso contra bactérias patogênicas de ambiente de cultivo de camarões (Litopenaeus vannamei)

Some infections caused by pathogenic microorganisms might shows high prevalence in farmed shrimp environments, compromising production and causing economic losses. Therefore, the search for compounds with antibiotic activity has become intensive, following the record of new antimicrobial-resistant bacteria. The study of those bioactive compounds in marine macroalgae has produced satisfactory results, such as the discovery of antibacterial activity against multiresistant strains. Accordingly, this study aims to research antibiotic activity in macroalgae extracts of Chlorophyta, Phaeophyta and Rhodophyta found in the coast of Ceará and also to evaluate the cytotoxicity activity against bacterial strains (Vibrio sp.) from shrimp farms (Litopenaeus vannamei). The extracts cytotoxicity was also evaluated. The results prove that there was antibacterial activity in ethanolic, acetonic, hexanic and methanolic extracts against bacterial strains of Vibrio with multiple resistance profile as well as displaying low cytotoxicity.

Algumas infecções causadas por micro-organismos patogênicos podem apresentar alta prevalência em ambientes de cultivo de camarões marinhos, comprometendo a produção e causando prejuízos econômicos aos aquicultores. Assim, tem-se tornado intensa a busca por compostos com atividade antibiótica pelo registro cada vez mais frequente de bactérias com perfil de resistência a antimicrobianos. A presença desses compostos com bioatividade em macroalgas marinhas tem revelado resultados satisfatórios, como a descoberta de ação antibacteriana contra cepas multirresistentes. Desta forma, decidiu-se pesquisar as propriedades antibióticas dos extratos de macroalgas das classes Chlorophyta, Phaeophyta e Rhodophyta, coletadas no litoral cearense, bem como avaliar a citotoxicidade destes extratos, frente a cepas bacterianas (Vibrio sp.) isoladas e provenientes de ambientes de cultivo de camarões marinhos (Litopenaeus vannamei). Os resultados comprovaram que houve atividade antibacteriana dos extratos etanólicos, acetônicos, hexânicos e metanólicos contra cepas bacterianas de Vibrio, além de apontar que os extratos de todas as espécies apresentaram baixa citotoxicidade.

Ecotypes and virulence factors of Salmonella spp. detected in shrimp farms in State of Ceara, Brazil / Ecotipos e fatores de virulência de Salmonella spp. detectadas em fazendas de carcinicultura do Ceará, Brasil

Our objective was to group in ecotypes 12 serovars of Salmonella isolated from shrimp farming environments in the State of Ceara (Northeast Brazil). Grouping was done based on genotypic virulence factors. Two groups based on the similarity of the Box-PCR were identified: a group consisting of three strains (01 S. ser. Madelia serovar and 02 S. ser. enterica subs. houtenae) and another group consisting of nine isolates (02 S. ser. Saintpaul serovars; 03 S. ser. Infantis; 02 S. ser. Panama; 01 S. enterica subs. enterica; and 01 S. enterica subs. houtenae). Distribution pattern of the serovars was not influenced by the origin matrices (water and sediment). Plasmid virulence genes pefA and invA were detected, unrelated to the serovar and environmental origin of the isolates. The presence of virulence genes in the isolates underlines the potential to trigger salmonellosis events via shrimp consumption. Biomonitoring of these sources of contamination should be encouraged as a protective measure, minimizing health risks and economic losses for the industry.

Nosso objetivo foi agrupar em ecotipos 12 sorovares de Salmonella isolados em ambientes de carcinicultura no Estado do Ceará. O agrupamento foi feito a partir da pesquisa de fatores genotípicos de virulência. Constatou-se a formação de dois grupos baseados na similaridade do Box-PCR: um grupo com três estirpes (01 sorovar S. ser. Madelia e 02 sorovares S. enterica subs. houtenae) e outro constituído por nove isolados (02 sorovares S. ser. Saintpaul, 03 sorovares S. ser. Infantis, 02 sorovares S. ser. Panama, 01 sorovar S. enterica subs. enterica e 01 sorovar S. enterica subs. houtenae). O padrão de distribuição dos sorovares não sofreu influência das matrizes de origem (água e sedimento). Os genes de virulência plasmidial pefA e invA foram detectados independente do sorovar e da origem ambiental dos isolados. A presença desses genes de virulência nos isolados de carcinicultura evidencia o potencial para desencadear eventos de salmonelose relacionados ao consumo de camarão. O biomonitoramento dessas fontes de contaminação deve ser incentivado como medida protetiva, minimizando os riscos do ponto de vista sanitário e das perdas econômicas para o setor da carcinicultura.

Multidrug-resistant Vibrio associated with an estuary affected by shrimp farming in Northeastern Brazil.

Bacteria of genus Vibrio with multidrug resistance in shrimp farm environment were recurrent. Thus, the aim of this study was to evaluate the antimicrobial resistance profile of 70 strains of Vibrio isolated from water and sediment of Acaraú estuary, Ceará, Brazil. In order to achieve this goal, disk diffusion technique was used with the following antimicrobial agents: ampicillin (Amp), aztreonam (Atm), cephalothin (Cef), cefotaxime (Ctx), ceftriaxone (Cro), ciprofloxacin (Cip), chloramphenicol (Clo), florfenicol (Flo), nitrofurantoin (Nit), gentamicin (Gen), oxytetracycline (Otc), tetracycline (Tet), streptomycin (Str), nalidixic acid (Nal), and sulfazotrim (Sut). All Vibrio strains were resistant to at least one antimicrobial agent, being verified as 17 multidrug-resistant profiles. All strains resistant to Otc and Tet were characterized to exhibit plasmidial resistance. Therefore, Vibrio strains from Acaraú estuary pose a risk to public health and aquatic culture.

Population dynamics and antimicrobial susceptibility of Aeromonas spp. along a salinity gradient in an urban estuary in Northeastern Brazil.

The main objective of this study was to quantify population and identify culturable species of Aeromonas in sediment and surface water collected along a salinity gradient in an urban estuary in Northeastern Brazil. Thirty sediment samples and 30 water samples were collected from 3 sampling locations (A, B and C) between October 2007 and April 2008. The Aeromonas count was 10-7050CFU/mL (A), 25-38,500CFU/mL (B) and<10CFU/mL (C) for water samples, and ∼100-37,500CFU/g (A), 1200-43,500CFU/g (B) and<10CFU/g (C) for sediment samples. Five species (Aeromonas caviae, A. sobria, A. trota, A. salmonicida and A. allosaccharophila) were identified among 41 isolates. All strains were sensitive to chloramphenicol and ceftriaxone, whereas 33 (80, 4%) strains were resistant to at least 2 of the 9 antibiotics tested. Resistance to erythromycin was mostly plasmidial. In conclusion, due to pollution, the Cocó River is contaminated by pathogenic strains of Aeromonas spp. with a high incidence of antibacterial resistance, posing a serious risk to human health.

Detection of virulence genes in environmental strains of Vibrio cholerae from estuaries in northeastern Brazil.

The objectives of this study were to detect the presence of Vibrio cholerae in tropical estuaries (Northeastern Brazil) and to search for virulence factors in the environmental isolates. Water and sediment samples were inoculated onto a vibrio-selective medium (TCBS), and colonies with morphological resemblance to V. cholerae were isolated. The cultures were identified phenotypically using a dichotomous key based on biochemical characteristics. The total DNA extracted was amplified by PCR to detect ompW and by multiplex PCR to detect the virulence genes ctx, tcp, zot and rfbO1. The results of the phenotypic and genotypic identification were compared. Nine strains of V. cholerae were identified phenotypically, five of which were confirmed by detection of the species-specific gene ompW. The dichotomous key was efficient at differentiating environmental strains of V. cholerae. Strains of V. cholerae were found in all four estuaries, but none possessed virulence genes.

DETECTION OF VIRULENCE GENES IN ENVIRONMENTAL STRAINS OF Vibrio cholerae FROM ESTUARIES IN NORTHEASTERN BRAZIL / Detecção de genes de virulência em estirpes de Vibrio cholerae isolados de estuários no Nordeste do Brasil

The objectives of this study were to detect the presence of Vibrio cholerae in tropical estuaries (Northeastern Brazil) and to search for virulence factors in the environmental isolates. Water and sediment samples were inoculated onto a vibrio-selective medium (TCBS), and colonies with morphological resemblance to V. cholerae were isolated. The cultures were identified phenotypically using a dichotomous key based on biochemical characteristics. The total DNA extracted was amplified by PCR to detect ompW and by multiplex PCR to detect the virulence genes ctx, tcp, zot and rfbO1. The results of the phenotypic and genotypic identification were compared. Nine strains of V. cholerae were identified phenotypically, five of which were confirmed by detection of the species-specific gene ompW. The dichotomous key was efficient at differentiating environmental strains of V. cholerae. Strains of V. cholerae were found in all four estuaries, but none possessed virulence genes.

O objetivo deste estudo foi detectar a presença potencial virulência de Vibrio cholerae isolado de estuários do Nordeste do Brasil. Amostras de água e sedimento foram coletadas e inoculadas sobre meio seletivo para víbrios (TCBS) e colônias com características morfológicas de V. cholerae foram isoladas. A identificação fenotípica seguiu chave dicotômica baseada em caraterísticas bioquímicas. Foram empregadas as técnicas de amplificação da polimerase em cadeia (PCR) utilizando o gene ompW e a de multiplex PCR para detecção de genes de virulência (ctx, tcp, zot e rfbO1). Os resultados da identificação das diferentes abordagens foram comparados. Nove cepas de V. cholerae foram identificadas fenotipicamente e cinco confirmadas através da detecção do gene ompW. A chave dicotômica utilizada foi eficiente para a confirmação da espécie. Os quatro estuários analisados apresentaram estirpes de V. cholerae, e nenhuma das cepas isoladas apresentaram genes de virulência.

[Familiar outbreak of botulism at Ceará state, Brazil: case report]. / Surto familiar de botulismo no estado do Ceará: relato de caso.

Report of a family outbreak of botulism food poisoning involving a death, where gaps in the completion of medical records were identified. The study aimed to describe the pathology and emphasize to health professionals the need to provide adequate information relevant to epidemiological investigation of compulsory notification diseases.

Surto familiar de botulismo no estado do Ceará: relato de caso / Familiar outbreak of botulism at Ceará state, Brazil: case report

Relato de surto familiar de botulismo por intoxicação alimentar, envolvendo um óbito, onde foram encontradas lacunas no preenchimento do prontuário. O objetivo foi descrever a patologia chamando a atenção dos profissionais de saúde para o fornecimento adequado de informações relevantes para a investigação epidemiológica de doenças de notificação compulsória.

Report of a family outbreak of botulism food poisoning involving a death, where gaps in the completion of medical records were identified. The study aimed to describe the pathology and emphasize to health professionals the need to provide adequate information relevant to epidemiological investigation of compulsory notification diseases.

Raw oysters can be a risk for infections

The aims of this study were to count and identify sucrose positive and negative vibrios isolated from cultivated Crassostrea rhizophorae oysters during their growing cycle. Every month for 12 months, 10 to 18 oysters were collected for study. Collections occurred at the Center for Studies of Coastal Aquaculture (CSCA), which is associated with the Institute of Marine Science, Labomar, located in Euzebio, Ceará, Brazil. Approximately 150 oysters and their intervalvular liquor were studied. Vibrio Standard Plates Counts (SPC) from oyster meat and their intervalvular liquor varied from 25 to 59,000,000 CFU/g. For most of the 12 months of the oysters' life, it was possible to identify Vibrio parahaemolyticus. Vibrio carchariae was identified in four collections. Among other isolated species, the most important, considering public health risks, was V. vulnificus, although only one strain was confirmed. We concluded that retail purchased oysters should never be eaten raw or undercooked because many species of the genus Vibrio are known to be pathogenic to humans and live naturally on and in shellfish throughout their life cycle.

Antibacterial activity of GUAVA, Psidium guajava Linnaeus, leaf extracts on diarrhea-causing enteric bacteria isolated from Seabob shrimp, Xiphopenaeus kroyeri (Heller).

Guava leaf tea of Psidium guajava Linnaeus is commonly used as a medicine against gastroenteritis and child diarrhea by those who cannot afford or do not have access to antibiotics. This study screened the antimicrobial effect of essential oils and methanol, hexane, ethyl acetate extracts from guava leaves. The extracts were tested against diarrhea-causing bacteria: Staphylococcus aureus, Salmonella spp. and Escherichia coli. Strains that were screened included isolates from seabob shrimp, Xiphopenaeus kroyeri (Heller) and laboratory-type strains. Of the bacteria tested, Staphylococcus aureus strains were most inhibited by the extracts. The methanol extract showed greatest bacterial inhibition. No statistically significant differences were observed between the tested extract concentrations and their effect. The essential oil extract showed inhibitory activity against S. aureus and Salmonella spp. The strains isolated from the shrimp showed some resistance to commercially available antibiotics. These data support the use of guava leaf-made medicines in diarrhea cases where access to commercial antibiotics is restricted. In conclusion, guava leaf extracts and essential oil are very active against S. aureus, thus making up important potential sources of new antimicrobial compounds.

Antibacterial activity of GUAVA, Psidium guajava Linnaeus, leaf extracts on diarrhea-causing enteric bacteria isolated from Seabob shrimp, Xiphopenaeus kroyeri (Heller) / Avaliação da atividade antibacteriana de extrato de folhas de goiabeira, Psidium guajava Linnaeus, sobre bactérias entéricas diarreiogênicas, isoladas de camarão sete-barbas, Xiphopenaeus kroyeri (Heller)

Guava leaf tea of Psidium guajava Linnaeus is commonly used as a medicine against gastroenteritis and child diarrhea by those who cannot afford or do not have access to antibiotics. This study screened the antimicrobial effect of essential oils and methanol, hexane, ethyl acetate extracts from guava leaves. The extracts were tested against diarrhea-causing bacteria: Staphylococcus aureus, Salmonella spp. and Escherichia coli. Strains that were screened included isolates from seabob shrimp, Xiphopenaeus kroyeri (Heller) and laboratory-type strains. Of the bacteria tested, Staphylococcus aureus strains were most inhibited by the extracts. The methanol extract showed greatest bacterial inhibition. No statistically significant differences were observed between the tested extract concentrations and their effect. The essential oil extract showed inhibitory activity against S. aureus and Salmonella spp. The strains isolated from the shrimp showed some resistance to commercially available antibiotics. These data support the use of guava leaf-made medicines in diarrhea cases where access to commercial antibiotics is restricted. In conclusion, guava leaf extracts and essential oil are very active against S. aureus, thus making up important potential sources of new antimicrobial compounds.

O chá de folhas de goiaba Psidium guajava Linnaeus é comumente usado como remédio nas gastrenterites e diarréias infantis por aqueles que não têm acesso a antibióticos. Esta pesquisa estudou o efeito antibacteriano sobre bactérias causadoras de diarréias, do óleo essencial e do extrato de folhas de goiabeira usando como diluente: metanol, hexano e acetato de etila. Os extratos foram testados sobre Staphylococcus aureus, Salmonella spp. e Escherichia coli. As bactérias testadas foram isoladas de camarão sete-barbas Xiphopenaeus kroyeri (Heller) usando-se como controle cepas padrão, de cada espécie. Das bactérias testadas, o melhor efeito inibitório foi observado sobre Staphylococcus aureus. O extrato de metanol apresentou maior inibição bacteriana. O óleo essencial mostrou ação inibitória contra S. aureus e Salmonella spp. Foi demonstrada alguma resistência das cepas isoladas de camarão aos antibióticos comerciais testados. Estes dados confirmam que remédios à base de folhas de goiabeira podem ser utilizados em casos de diarréia provocada por essas bactérias, quando o uso de antibiótico for restrito. Conclui-se que extratos de folhas de goiaba e o seu óleo essencial são muito ativos contra S. aureus, tornando-os importantes fontes em potencial de novos compostos antimicrobianos.

Detection of Vibrio parahaemolyticus and Vibrio cholerae in oyster, Crassostrea rhizophorae, collected from a natural nursery in the Cocó river estuary, Fortaleza, Ceará, Brazil

As ostras são alimentos marinhos freqüentemente ingeridos crus ou parcialmente cozidos. Por esta razão, o risco para a saúde dos consumidores desses produtos é muito elevado, principalmente, quando são de regiões tropicais. Foi estudada a presença de Vibrio cholerae e Vibrio parahaemolyticus em ostras de um estuário na região Nordeste do Brasil. Trezentas ostras foram analisadas, em um período de 8 meses. A salinidade da água, no local de coleta, variou de 3 a 27ë. V. cholerae foi o vibrio mais freqüentemente detectado (33,3 por cento das amostras). Dos 22 isolados, 20 foram identificados como V. cholerae não-O1/não-O139, duas delas apresentando forma rugosa sendo a maioria das demais pertencente ao tipo fermentativo Heiberg II. V. parahaemolyticus foi isolado em apenas umas das coletas. Foram, também, identificadas nas amostras isolados de Providencia spp., Klebsiella spp., Proteus spp. e Morganella morganii.

Coliformes isolados de utensílios e equipamentos, na linha de processamento de camarão, de uma indústria de pescado de Fortaleza, Ceará / Coliforms bacilli of utensils and shrimp-processing equipaments of a fishing industry in Fortaleza, Ceará

Teve como objetivo isolar organismos do grupo dos coliformes de utensílios e equipamentos, na linha de processamento de camarão, de uma indústria de pescado, de Fortaleza, Ceará. Os equipamentos e utensílios amostrados pertenciam a duas linhas de diferentes tipos de processamento (camarão com e sem carapaça, congelados). Foram detectados coliformes nos equipamentos e utensílios higienizados e não higienizados, sendo que durante a terceira e quarta coleta se conseguiu um maior isolamento de cepas de Escherichia coli. Também foi investigada a resistência dessas cepas a diferentes concentrações de cloro. Foi possível recuperar células viáveis de Escherichia coli das amostras de utensílios higienizados e não higienizados em soluções de até 116 ppm de cloro livre. As cepas isoladas dos utensílios não higienizados não apresentaram resultados muito diferentes daqueles obtidos para os utensílios higienizados.