Multiple Tube Technique Research Articles

Bacteriological assessment of fruit pulp sold in supermarkets in São Raimundo das Mangabeiras, Maranhão State, Brazil

Natural fruit pulp is highly appreciated because it retains the flavor and nutrients of the fresh fruit. However, fruit pulp is susceptible to contamination by pathogenic bacteria, mainly because of improper handling and storage. Therefore, this study evaluated and quantified the presence of pathogenic bacteria in fruit pulp sold in São Raimundo das Mangabeiras, Maranhão, Brazil. Two fruit pulp samples each of açaí (A and B), acerola (C and D), cajá (E and F), cashew (G and H), and passion fruit (I and J) were obtained from supermarkets and subjected to the following microbiological analyses: enumeration of mesophilic bacteria using plate count agar; quantification of total (TC) and thermotolerant (TTC) coliforms using the multiple tube technique; qualitative detection of Escherichia coli on eosin methylene blue agar and that of Salmonella on xylose lysine base agar and enteric agar. Mesophilic bacteria were found to grow in all the samples, with the highest value obtained for the acerola pulp (sample D; average: 1.08 x 105 colony-forming units g-1). However, all samples were in accordance with the Brazilian legislation for this parameter. The most probable number of colonies (MPN g-1) of TC and TTC were ≥1,100 in açaí (sample A), cajá (sample E), and cashew (sample G) pulps, which is in disagreement with the maximum value allowed. E. coli and Salmonella were not found to grow in the samples evaluated in this study. Collectively, the data indicate inadequate handling and storage in the production chain of fruit pulp sold in the municipality of São Raimundo das Mangabeiras, suggesting that the population in the region is exposed to a probable risk of food contamination.

Physico-chemical and Coliform Bacteria characterization of Selected Shallow wells in Awe, South-western Nigeria

Due to lack of town-water supply in Awe area within South-western Nigeria, residents rely on shallow groundwater for household utilization. The aim of the present work is to study the water quality from selected hand-dug wells in Awe communities. The study involved analyses of major ions and trace elements which included iron, lead, zinc, copper and cadmium; and assessment of coliform bacteria counts in thirty (30) shallow hand-dug wells. Spectrophotometric method was used for chemical analyses while multiple-tube technique was employed for the bacterial enumeration in water. From the results, the pH was between 5.9 and 7.4 mg/l, Electrical Conductivity (EC) ranged from 20 to 1000 μS/cm while total dissolved solids (TDS) ranged between 30 and 500 mg/L. Concentration of major ions in mg/L were; calcium, 9.63- 76.8, magnesium, 4.58- 32.03, sodium, 2.12 – 27.85 and potassium, 1.68- 20.29 while for anions bicarbonate, 46- 260, nitrate, 0.1- 0.42; sulphate 4- 26 and chloride-7.81- 103.6. Trace elements occurred below detection limits ranging from < 0.01 to < 0.05 mg/L. From the Piper plot, the dominant hydrogeochemical facies was Ca-HC03 type. The concentrations of the major ions are within the acceptable limits. However, there is presence of coliform bacteria in most wells and the growth were too numerous to count in some wells. This indicated anthropogenic inputs from infiltration of contaminated water most likely from poorly maintained human waste storage facilities such as toilet facilities and poor maintenance culture of the sampled hand-dug wells.

Pseudomonas aeruginosa biofilm formers in drinking water

Currently there has been an increase in demand for bottled water, this is due to the population’s dissatisfaction with the quality of water provided by public agencies. The present study sought to evaluate the presence of biofilm-forming P. aeruginosa in bottled drinking water. Thirty-five typical bottled water samples were selected to identify the presence of P. aeruginosa and its ability to form bacterial biofilm. The methodology used to verify the presence of P. aeruginosa followed the multiple tube technique and the evaluation of biofilm forming capacity followed the microdilution technique, with the optical capacity read by spectrophotometry at 620 nm. The presence of P. aeruginosa was detected in 26% of the samples analyzed, representing nine of the 35 samples tested. Of these, 55% had the ability to form biofilm. The present study shows that the presence of P. aeruginosa, which is capable of forming biofilms, is a risk factor for public health because of the widespread commercialisation of bottled water.

Assessment of nitrate, trace elements and bacterial contamination of groundwater in ilora area of southwestern nigeria

Assessments of groundwater pollution parameters were carried out in groundwater samples collected from selected shallow hand-dug wells across Ilora township. The analysed parameters were nitrate, trace elements including, iron, cobalt, chromium, manganese, zinc, arsenic, cadmium and lead, and bacteria count in water; using spectrophotometric method, HM Metalyser 5000 and multiple tube techniques respectively. The pH of the samples was between 6.4 and 7.6 and TDS range was 50 - 640 mg/l. The concentration of nitrate (NO3) in water was 12.8 - 274 mg/l. For trace elements concentrations in µg/l ; iron (Fe): 150 – 880, Cobalt (Co): 1 – 100, Manganese (Mn): 0.01 - 140, Chromium (Cr): 0.01 – 0.31, Zinc (Zn): 1.86 - 9.97, Arsenic (As): 3.11 - 20.80, Cadmium (Cd): 0.71 - 4.76, Lead (Pb): 1.00 – 6.82. Based on the average concentration of the trace elements the order of abundance was Fe > Co > Mn > As > Zn > Pb > Cd > Cr. Total coliform count (TCC) in groundwater samples were between 18 and 370 cfu/100mL. From the evaluation of the degree of association between the parameters, a moderate to strong positive relationship occurred between Fe/Mn (0.59), Fe/Cr (0.85), Fe/TC (0.56), NO3/Co (0.56), NO3/Mn (0.48), NO3/Cd (0.51) and Mn/Pb (0.85). Presence of coliform bacteria in the groundwater samples indicated fecal contamination from surface environment. Comparing the parameters with guideline standards for drinking water, most of the hand-dug wells are contaminated with nitrate, five wells were contaminated with either arsenic and/or cadmium, while water from some of the wells may have objectionable taste due to high iron content. The high values of cadmium and arsenic in some wells are harmful to human health and appropriate treatment is needed. For bacteria contamination, deeper wells are recommended, and the water should to be treated and boiled prior to consumption.

MICROBIOLOGICAL AND PHYSICOCHEMICAL QUALITIES OF IKPOBA RIVER IMPACTED BY PIPED TREATED BREWERY EFFLUENT STREAM

The impact of discharged treated brewery effluent stream on the microbial andphysicochemical qualities of Ikpoba River which is serving as a receptacle for the treatedwastewater was investigated. Serial dilution, pour plate and multiple tube technique wereemployed in evaluating the culturable microbial diversity of the water samples and thetreated brewery wastewater. The physicochemical attributes of the freshwater and effluentsamples were ascertained using titrimetric and spectrophotometric procedures. The meanheterotrophic bacterial counts for the upstream freshwater samples ranged from 3.7 ×102cfu/ml ± 2.1 to 0. 6 × 102 cfu/ml ± 2. The mean heterotrophic fungal counts for watersamples obtained at the point of discharge ranged from 0.7×103 cfu/ml ± 6.6 to 9.7 × 103cfu/ml ± 6.1. The total coliform counts recorded for water samples obtained at thedownstream sampling point ranged from 2 MPN/105 ml to 5 MPN/105 ml. The E. colicounts for the treated brewery wastewater varied from 2 MPN/105 ml to 4 MPN/105 ml. Theobserved differences in the mean heterotrophic bacterial and fungal counts was statisticallysignificant (P<0.05). Seven bacterial and four fungal isolates were characterized andtentatively identified; Proteus vulgaris, Bacillus cereus, Klebsiella pneumoniae, Escherichiacoli, Streptococcus sp., Pseudomonas sp., Enterobacter aerogenes, Saccharomycescerevisiae, Candida tropicalis, Penicillium sp. and Aspergillus niger. The mean pH, turbidityand conductivity of the respective samples ranged from 5.63±0.05 to 6.78±0.05, 4.1 NTU±0.21 to 6.81 NTU ±0.55 and 3.3 ?s/cm ±0.25 to 73.3 ?s/cm ±6.56 respectively. Thedischarged brewery effluent stream impacted negatively on the as aesthetic quality of theIkpoba River at the point of discharge. The microbiological quality of both the watersamples and the treated effluent is very poor when compared with Federal Ministry ofEnvironment limits for potable water, hence discouraging the direct consumption of thewater sourced from the Ikpoba River at these sampling points by individuals living along thecatchment area of the river

Groundwater quality evaluation: a case study of Igando waste dumpsite, southwestern Nigeria

The quality of groundwater samples around Igando area, Lagos State, Nigeria was investigated with the aim of detecting possible influence of dumpsites on nearby aquifers. Thirty-seven (37) groundwater samples were evaluated for their suitability in drinking and agricultural purposes. Physical parameters were determined in situ using portable multi-meter. Flame absorption was used to determine the concentrations of major cations while ion chromatography and titrimetry was used for anions’ concentration. Bacteriological test was conducted using multiple tube technique. Results of in-situ physical parameters revealed pH range of 7.01–7.79, EC range of 20–880 μS/cm while TDS range from 13–590 mg/L. Laboratory analyses showed Ca2+ concentration ranging 1.60–72.80 mg/L and HCO3− ranging 19.52–204.96 mg/L as the dominant ions. None of the ions’ concentrations exceed the WHO drinking limit. Water Quality Index (WQI) classification showed that all samples fall within good to excellent water categories. The majority of the samples are suitable for irrigation using indices such as Sodium Adsorption Ratio (SAR), Kelly’s ratio (KR), and Magnesium Hazard (MH). Bacteriological analyses revealed low total bacterial count and E-coli absence making the samples safe for drinking. Piper diagram indicated two main water-facies (Ca–HCO3 and the Mixed Ca–Mg–Cl). Gibbs’s plots showed that the samples are primarily influenced by rock weathering, while precipitation also contributed. Chloro-Alkaline Index confirmed direct ion-exchange process. Cluster analyses revealed four groups: the first revealed influence of groundwater by anthropogenic activities in the study area, the second and third revealed lithological origin of ions in the water while group 4 indicated pH low influence on the dissolved ions in the waters. The groundwater quality can be said to be fair-good, thus suggestive of minimal interactions between the dumpsites and the groundwater in the area at the time of testing.

Preliminary Assessment of Water Quality in Some Hydrocarbon-imparted Ogoni Communities in River State, Nigeria

Aim: This study aimed to assess the quality of drinking water in some hydrocarbon-impacted Ogoni communities.
 Study Design: The study employ a cross-sectional and analytical design using stratified sampling method.
 Place and Duration of Study: Department of Medical Laboratory Science of Rivers State University, Giolee Global Resource Limited and Environmental Consultancy Services between March 2020 and March 2021.
 Methodology: Water samples were collected from (20 hydrocarbon- impacted communities) in the 4 Local Government Area (LGAs) of Ogoni land. These water samples were analyzed to determine the physicochemical, bacteriological, heavy metal and total petroleum hydrocarbon (TPH) parameters using standard methods and operational procedures. The data obtained were subjected to descriptive statistical analysis. The general linearized model (GIG) was used to generate analysis of variance (ANOVA) mean and standard error and arrange, statistically significant was set as p-value of .05 (95% confidence limit). Pearson correlation test was used to calculate the correlation between TPH, Heavy metal, and physicochemical parameters in hydrocarbon and non-hydrocarbon impacted communities. All statistical analyses were performed using GraphPad Prism (Version 8).
 Results: The results obtained for physicochemical parameters were pH 4.3±0.8 mg/l, EC 0.03±0.05 mg/l, DO 5.5±1.6 mg/l, Temp 25.0±0.0 mg/l, Mv 0.32±0.27 mg/l, Nitrite 0.0058±013 mg/l, Nitrate 0.1530±158 mg/l. These results were all below the recommended standard for Nigeria standard of drinking water quality (NSDWQ) and World Health Organization (WHO). The bacteriological analyses were carried out using multiple tubes technique (Most Probable Number), total coliform count, (TC), total heterotrophic count (THBC) and total fungal count (TFC). The results obtained were 0.941±2.397 cfu/ml, 89.3±176.6 cfu/ml, 297.8±144.4 cfu/ml, and 0.32±0.84 cfu/ml respectively. The p-values for TFC (<0.0002) were statistically significant. Heavy metal profiling was: Cr 0.194±0.320 mg/l, Cd 0.469±0.569 mg/l, Cu 0.211±0.348 mg/l, Pb 0.0336±0.20 mg/l, Fe 0.705±1.244 mg/l, Zn 0.258±0.249 mg/l, respectively. Generally, the concentration of heavy metal increased more than the standard recommended by NSDWQ and WHO except for Zn 0.255±0.249 mg/l, and Cu 0.56±0.50 mg/l, that is slightly lower than the acceptable limit recommended by WHO and NSWWQ. The sequences of heavy metal concentration were in Cd > Cr> Pb>Fe> Cu.>Zn. The statistical significance values for Pb p=.003 and for Zn p=.009 were statistically significant. The concentration of TPH were (349.9 ppm/ml) higher than the recommended values for NSDWQ and WHO.
 Conclusion: The findings in this research reviewed a worrisome level of TPH and Pb, and which could have devastating impact on bacterial biodiversity.

Storage tanks for household water usage in Brazil: Microbiological and chemical quality, and maintenance of sanitary conditions

Introduction: Storage tanks for household water usage guarantees convenience and safety forconsumers in relation to water intermittency. Neglecting a minimal care for storage tanks can turnthem into a source of water unfit for consumption. Objective: Evaluate the physical, chemical, andmicrobiological quality of water in household tanks to highlight the need for individual actions toguarantee the quality of water consumed at home. Methods: Residents of 217 homes answereda questionnaire to gather information about the water storage tank conditions and maintenance.Chlorine dosing, pH and temperature measurements were performed in situ and metal analyseswere made using an inductively coupled plasma mass spectrometry (ICP-MS). The presence ofparasites was evaluated using the spontaneous sedimentation technique and presence of bacteriafrom the coliform groups (total and fecal) were made using the multiple-tube technique with thechromogenic substrate. Results: Results showed that 115 participants knew the correct storage tankmaintenance period and 109 participants did not perform the storage tank maintenance at therecommended frequency. Mean values of chlorine, pH, and temperature were 1.34 mg/L, 6.5, and25.4 ºC, respectively. Average concentrations of metals were below the maximum values allowed.Parasites and bacteria were not detected. Tests indicated the water samples were in accordancewith the potable water quality standards endorsed or recommended by the Brazilian legislation.Conclusion: Results did not show microbiological contamination in study samples. Nevertheless, it isnecessary to keep the population regularly informed about the importance to maintain storage watertanks clean. Currently, there is a growing concern with the development of individual actions aimedat human health and prevention of water-related diseases concerning its access and use. Therefore,we need health education programs to guide community participation into the promotion of a betterquality of life.

Ambulant Market Foods: Consumer Problem or Solution?

Background: The sale of food by street vendors is an activity of economic, sanitary, and nutritional importance, but these foods can pose a high risk to the health of consumers in inadequate conditions of preparation and storage. The aim of this study was to investigate the preparation conditions and the hygienic-sanitary quality of food sold by street vendors in the vicinity of four campuses of a University Center in Maceió, Brazil. The aim was to verify the sanitary hygienic conditions of the preparation site as well as to carry out a microbiological analysis of the commercialized foods. Methods: In this cross-sectional study, the microbiological analyses were carried out on different foods following the multiple tube technique for coliforms and surface sowing method and pour-plate assay for Salmonella sp., molds, and yeasts. In addition, an observational checklist was applied involving 21 trailer tent owners in the vicinity of the four campuses of the University Center. Inclusion criterion included adult vendors selling food near four campuses at the Centro Universitário de Maceió, Brazil. Exclusion criteria consisted of street vendors due to the difficulty in locating them. Results: The findings showed high presence of microorganisms; a high degree of risk was observed in 100% of the studied places. Conclusion: Hygienic-sanitary interventions are necessary to train these vendors on the importance of good manufacturing practices, since this will probably not result in food-borne outbreaks.

Impactos ambientais macroscópicos e qualidade da água em nascentes localizadas na Vila Bananeira, Arapiraca-AL

RESUMO: O crescimento populacional vem acompanhado de uma constante degradação do meio ambiente, colocando em risco o equilíbrio ecológico de diversos ecossistemas afetando, direta ou indiretamente, muitas nascentes. Nascentes são sistemas ambientais importantes para a manutenção do equilíbrio hidrológico e são as principais fontes de água para um rio. Nesse contexto, e considerando que a água é um recurso natural imprescindível para diversas atividades humanas, objetivou-se, com este estudo, avaliar o grau de conservação de nascentes localizadas na Vila Bananeira, Arapiraca-AL, através do Índice de Impacto Ambiental em Nascentes (IIAN), assim como averiguar a qualidade da água proveniente dessas nascentes por meio da análise de alguns parâmetros físico-químicos e microbiológicos nas amostras coletadas. O estudo foi realizado nos meses de Janeiro e Fevereiro de 2020 e dividido em duas etapas. A primeira consistiu em um trabalho de campo com a observação dos parâmetros macroscópicos, para determinação do IIAN. Sete nascentes foram avaliadas. Na segunda etapa, análises laboratoriais foram realizadas para determinação da qualidade da água das nascentes em estudo. Amostras das três nascentes que apresentavam maior volume de água foram encaminhadas aos laboratórios da UFAL/ Campus Arapiraca. Parâmetros físico-químicos como: pH, turbidez e condutividade foram determinados utilizando-se aparelhos específicos para este fim. Também foram realizados testes microbiológicos para averiguar a presença de bactérias do grupo coliformes. Para a análise microbiológica, utilizou-se a técnica dos tubos múltiplos. Após as análises, constatou-se que seis nascentes apresentavam grau de conservação razoável (classe C) e uma delas, a nascente denominada “A”, grau de conservação ruim (classe D). Os valores de pH encontrados estavam ligeiramente abaixo daquele exigido pela legislação, mas foram classificados como satisfatórios para consumo humano. Os valores de turbidez estavam dentro da normalidade, considerando os valores de referência apontados pela legislação. Os valores de condutividade encontrados foram: 304,9; 302,1 e 355,8 µS/cm para as nascentes “A”, “B” e “C”, respectivamente. Quanto aos resultados microbiológicos, somente a nascente “A” apresentou contaminação por coliformes fecais. Os resultados encontrados nesta pesquisa, tanto quanto ao grau de conservação da nascente “A”, considerado ruim, como os achados microbiológicos, são preocupantes, dada a importância dessa nascente para a comunidade local e circunvizinha, uma vez que se trata da principal fonte de água da região.
 PALAVRAS-CHAVES: conservação, recursos hídricos, impactos sócio-ambiental.

Physico-chemical and bacteriological evaluation of hand-dug wells in major markets in south-western Nigeria

Background: Quality of drinking water has always been a major health concern. Lack of access to safely managed water is responsible for high burden of waterborne diseases which disproportionately impact children and equity of women in Nigeria. This study, therefore, assessed the physico-chemical and bacteriological qualities of hand-dug wells in some major markets in Ibadan Southwestern, Nigeria. Methods: Twenty-two (22) water samples from hand-dug wells, measured sequentially along seven major marketswere tested for their physico-chemical and bacteriological characteristics. Following standard sampling procedures, in-situ measurements were taken for total dissolved solute (TDS), pH, electrical conductivity (EC), salinity and temperature. The most probable number – multiple tube technique was used for coliform enumeration in addition to total viable bacteria count (TVBC). Results: Mean pH (7.37±0.47), TDS (597.51±109.06mg/L), EC (748.79±110.67µS/cm), salinity (0.05±0.01mg/L), and temperature (28.75±0.58ºC) for all the marketswere withinWHO permissible limits except pH. High pH may be due to high organic matter content of the water samples. Bacteria genera comprising Esherichiacoli (37.5%), Staphylococcus aureus (25%), Proteus vulgaris (14.6%), Baccilusspp. (12.5%), Pseudomonas aeruginosa (8.3%) and Klebsiella spp. (2.1%).The mean TVBC of 500 to 192,000cfu/ml were higher than the stipulated WHO standard of <1cfu/100ml.The presence of Esherichiacoli in hand-dug well water samples revealed human or animal faecal contamination.Conclusions: Water from these sources, intended for human consumption or washing of food items, maycompromise food safety and pose severe health risks to consumers. The provision of deep tube wells for safe drinking water, periodically testing of the water quality, and education of the users on improved hygiene practices will help in the provision of safe water to the public consumers.Keywords: Water quality, Hand-dug well, Bacteriological analysis, Coliforms,

Qualidade microbiológica da água de poços artesianos localizados na Cidade de Acari, Rio Grande do Norte

Este estudo teve como objetivo analisar, mediante caracterização microbiológica, a qualidade da água de dois poços artesianos localizados na cidade de Acari-RN. As amostras de água foram coletadas em dois poços artesianos localizado na zona rural da cidade de Acari-RN e encaminhadas para serem submetidas à análises realizadas em triplicatas no Laboratório de Microbiologia de Alimentos, da Universidade Federal de Campina Grande, Campus Pombal, Paraíba. Os parâmetros analisados foram: coliformes totais, coliformes termotolerantes, Escherichia coli, determinados seguindo as metodologias da CETESB (Companhia Ambiental do Estado de São Paulo). A determinação do número mais provável de coliformes nas amostras foram obtidas por meio da aplicação da técnica de tubos múltiplos seriados, sendo também realizada a análise de diferenciação de coliformes termotolerantes. Como resultados, as amostras analisadas apresentaram uma variação de 320 a 360 NMP.org/100 mL na contagem de coliformes fecais, resultado semelhante foi obtido para coliformes termotolerantes refrente aos dois poços artesianos, sendo que o maior valor foi observado no poço artesiano 2 com 240 NMP.org/100 mL, a Escherichia coli apresentou valores variando de <1,4 a <1,9 NMP.org/100 mL, sendo assim, as águas analisadas são consideradas impróprias para o consumo de acordo com Portaria de N° 5/2017 do Ministério da Saúde por configurar risco à saúde da população.

Estudo da qualidade microbiológica de linguiças provenientes do Rio Grande do Sul e do perfil de suscetibilidade das bactérias isoladas

Atualmente a ocorrência de doenças bacterianas transmitidas pela ingestão de alimentos contaminados, como as linguiças, é um alerta no dia a dia da população. As principais bactérias causadoras destes distúrbios são os coliformes termotolerantes, que podem apresentar um alto índice de resistência, tornando-se mais patogênicos aos seres humanos. Dessa forma, é importante a realização de um controle microbiológico em todos os alimentos antes de consumi-los. Este trabalho teve por objetivo a análise da qualidade microbiológica de linguiças, provenientes de diferentes regiões do estado do Rio Grande do Sul, e o estudo do perfil de suscetibilidade das bactérias isoladas destas amostras. A análise microbiológica foi realizada através da técnica dos tubos múltiplos (Número Mais Provável por grama de amostra) e o perfil de suscetibilidade pelo método de Kirby-Bauer. Os resultados das análises microbiológicas demonstraram que 100% (16) das amostras analisadas estavam próprias para o consumo humano. Foram avaliados os perfis de suscetibilidade de 28 bactérias isoladas, sendo que estas apresentaram sensibilidade em 85% de todos antimicrobianos testados, 2% dos perfis foram considerados intermediários e 13% resistentes. Através desta pesquisa se obteve informações de grande valia para toda a comunidade, as quais ajudarão a minimizar e prevenir infecções alimentares decorrentes do consumo destes embutidos.

Nitratation in pilot-scale bioreactors fed with effluent from a submerged biological aerated filter used in the treatment of dog wastewater

ABSTRACT Nitrification is a biochemical process that allows oxidation of ammonium ion to nitrite, and nitrite to nitrate in a system. Aerobic processes, such as use of submerged biological aerated filter (SBAF), enable nitrification. However, some variables that are entirely unavailable or not available at the required concentration range may hamper the process. In this study, nitratation under high dissolved oxygen (DO) concentrations was evaluated in laboratory-scale bioreactors containing 10% inoculum (0.5 kg kg−1) fed with affluent from a SBAF that receive the sewage generated from washing the bays of a dog kennel. The following variables were monitored over time: ammoniacal nitrogen (12.44–29.62 mg L−1), nitrite (0.28–0.54 mg L−1), nitrate (1.75–3.55 mg L−1), pH (8.11 ± 0.62), temperature (21.61 ± 1.24°C) and DO (9.69 ± 0.36 mg L−1). Quantification of nitrifying bacteria by the multiple tube technique showed the value of 1.4 × 1012 MPN mL−1for ammonia-oxidizing bacteria (AOB) and 9.2 × 1014 MPN mL−1 for nitrite-oxidizing bacteria. These values were higher than those found in a synthetic medium, which can be explained by the greater availability of ammonium and nitrite in the effluent. By the extraction of genomic DNA, and PCR, with specific primers, the presence of the AmoA (Ammonia monooxygenase) gene for AOB and of the Nitrobacter was detected in the bioreactor samples. By PCR-DGGE, the sequenced bands showed high similarity with denitrifying bacteria, such as Pseudomonas, Limnobacter, Thauera, Rhodococcus, and Thiobacillus. Thus, the saturation of dissolved oxygen in the system resulted in improvement in the nitratation step and allowed detection of bacterial genera involved in the process.

Determinação de bactérias do grupo dos coliformes no tecido mole de Mytella guyanensis extraídas em Cananéia/SP, Brasil

This study aimed to evaluate the microbiological quality of water and tissue samples of Mytella guyanensis (Mollusk: Bivalve),a species of relevant commercial interest and is a direct part of the income and food of traditional communities in coastalregions. This study was carried out in two communities in the Cananeia Estuary known as Retiro and Itanhoapina. Duringthe period of 2017, where the species is collected for human consumption, water and bivalve samples were collectedin the localities in order to determine the concentrations of total and thermotolerant coliforms. The samples of water andM. guyanensis were analyzed to determine the Most Probable Number (MPN) of Coliforms, based on the Multiple TubeTechnique. The results of the analyses showed low concentrations of coliforms in the water samples, with a similar result forthe tissue samples of the individuals collected. The water analysis showed a geometric mean of 34.81 total coliforms and20.70 MPN 100 mL-1 of thermotolerant coliforms. The averages of coliforms in the soft tissues of M. guyanensis were 190MPN g -1 for total coliforms and 174 MPN g -1 for thermotolerant coliforms. The concentrations of coliforms in the tissue ofthe collected specimens showed a positive correlation with temperature and a negative correlation with salinity. There weresignificant differences between seasonality in relation to the concentration of total and thermotolerant coliforms in the tissue.The summer rainy season showed the highest seasonal average of coliforms in M. guyanensis. All values obtained for MPNof coliforms were below the limit established by the legislation.

Biocorrosion Inhibitory Potential of Aqueous Extract of Phyllanthus amarus against Acid Producing Bacteria

Biocorrosion is a form of corrosion of metallic and concrete materials mediated by microorganisms. Acid producing bacteria are major culprits in the corrosion of materials in the environment. This study focused on the inhibition of biocorrosion by acid producing bacteria using aqueous extract of Phyllanthus amarus (PAAE). Acid producing bacteria were isolated from produced water samples collected from oilfields located in Niger Delta, Nigeria. Multiple fermentation tube technique was adopted for the isolation of the acid producing bacteria using phenol red dextrose broth as culture broth medium. The gravimetric analysis was performed with different concentrations of the plant extract incorporated in universal culture bottles containing broth, sample and carbon steel coupon. The setup was incubated at 20ºC, 30ºC and 40ºC for 7 days and for 14 days. The least corrosion rate (CR) at 20ºC, 30ºC and 40ºC for the 7 days test were 1.446mp/y (80mg/ml PAAE); 27.558mp/y (5 mg/mlLeu+20 mg/ml PAAE) and 5.134 mp/y (80 mg/ml PAAE) with corresponding inhibition efficiency (IE) of 81.92, 87.750 and 80.91 respectively. For the 14 days, the CR values at 20ºC, 30ºC and 40ºC were: 3.192mp/y (5mg/mlLeu+20mg/ml PAAE); 1.458 mp/y (5 mg/mlLeu + 20 mg/ml PAAE) and 117.345mp/y (5 mg/mlLeu + 20 mg/ml PAAE) with corresponding IE of 86.09, 83.87 and 98.89 respectively. The results obtained show that the extract could be considered as a good inhibitor for the biocorrosion of carbon steel mediated by acid producing bacteria.

Efficiency of a sewage treatment station in the elimination of fecal contamination

Sewage from the various water uses such as domestic and industrial uses, as well as a high content of organic matter may contain chemical, toxic and pathogenic microorganisms. The present study was developed at the Sewage Treatment Station (ETE) in the municipality of Santa Helena de Goiás - Goiás and had as objective to evaluate the efficiency of the sewage treatment process in the elimination of fecal microbial contamination regarding the level of thermotolerant coliforms . Samples were collected in the months of March, April, May and June, which corresponded, respectively, to the rainy and dry season. The samples collected at the arrival of the raw sewage, in the final emissary, source spring being upstream and upstream were conditioned at 4ºC until the moment of the analysis; the Most Probable Number (NMP) or multiple tubes technique was used. It was verified that the ETE reached a significant efficiency index in the elimination of fecal coliforms, and in the period of rain there was a reduction of 99.8% and in the period of the drought a reduction of 99.7% in the fecal contamination after the treatment of sewage.

Avaliação da qualidade microbiológica da água do córrego Barreirinho no município de Ibirité-MG. Uma comparação com o Kit Enzquik

O córrego Barreirinho, objeto desse estudo, situado no município Ibirité-MG, vem sendo utilizado pela população do entorno principalmente para irrigação de hortaliças, mas a qualidade microbiológica do mesmo ainda não foi avaliada. O objetivo deste estudo foi avaliar os parâmetros físico-químicos e microbiológicos da água deste córrego e compará-los com os padrões da Resolução N°357 do CONAMA. A metodologia utilizada foi a técnica de tubos múltiplos e análise com o Kit de Detecção Rápida EnZquik. Os resultados das análises deste estudo demonstraram que os pontos próximos à nascente e no meio do curso d’água, com irrigação das hortas, mostram resultados semelhantes; as águas nesses pontos podem ser utilizadas para irrigação de hortaliças e consumo humano após tratamento simplificado. Os testes apontaram que no final do curso, na área urbana, a água é imprópria para qualquer uso. A semelhança entre os resultados obtidos com as duas técnicas permite sugerir que o Kit Enzquik, pode futuramente substituir técnicas utilizadas em laboratório, diminuindo o tempo de incubação e análise com outras metodologias, gerando um resultado quase instantâneo.

Evaluation of the immune responses of the brown mussel Perna perna as indicators of fecal pollution

The mussel Perna perna is an intertidal bivalve that is widely distributed, cultivated and consumed in South Africa, Brazil and Venezuela. Among marine resources, bivalve mollusks are one of the most impacted by anthropogenic pollution, as they can accumulate pathogenic bacteria and water pollutants. Hemocytes are molluscan defense cells, and their abundance and functions can be affected in response to contaminants, such as bacterial load. However, no previous study has investigated the immune response of P. perna hemocytes. The aim of this study was to evaluate several immune parameters in P. perna as indicators of fecal pollution in mussel hemolymph and in seawater. We collected mussels and adjacent seawater from beaches with different levels of fecal contamination in Rio de Janeiro state (Brazil): Vermelha Beach (VB); Icaraí Beach (IB); Urca Beach (UB); and Jurujuba Beach (JB). Hemocyte parameters (density, morphology, phagocytic activity and production of Reactive Oxygen Species - ROS) were evaluated using flow cytometry. We quantified Fecal Indicator Bacteria (FIB) in seawater by the multiple tubes technique for each beach and for hemolymph by the spread-plate technique. In agreement with historical evaluation of fecal contamination levels, UB presented the highest FIB abundance in seawater (thermotolerant coliforms, TEC = 1600 NMP 100 mL−1), whereas VB exhibited the lowest (TEC = 17 NMP 100 mL−1). UB mussels had six and eight times higher hemocyte density and phagocytic activity, respectively, than mussels from VB. Mussels from VB and IB presented a significantly lower number of total coliforms in hemolymph and a significantly higher relative internal complexity of hemocytes than those from UB and JB (p ≤ 0.01, PERMANOVA). ROS production by hemocytes was significantly lower in mussels from VB compared to those from JB (p = 0.04, ANOVA). Our results indicate a significant relationship between the level of fecal contamination in aquatic environments and the immune response of mussel hemocytes. Immune-related parameters may therefore be useful as indicators of bivalve health and environmental quality. Our flow cytometric analysis of P. perna hemocytes represents a new approach for studying Perna perna biology and might represent a novel tool for measuring organic pollution and water quality.

Análisis de la contaminación por Coliformes termotolerantes en el estuario del río Ranchería, la Guajira (Colombia)

El estuario del río Ranchería es una fuente hídrica de gran importancia para el municipio de Riohacha; formado por diferentes cuerpos de agua constituye un sistema dinámico y complejo que abastece tanto a centros poblados como rurales. Uno de los criterios más usados para la determinación de la calidad del agua es la medición de Coliformes Termotolerantes (CTT). Con el objetivo de estudiar la distribución espaciotemporal de estos elementos se colectaron muestras de agua en cinco zonas diferentes y se analizó el contenido de CTT mediante la técnica de tubos múltiples (NMP/100 ml). Los muestreos se realizaron cada 15 días, entre septiembre de 2014 y agosto de 2015, en los cuales no se establecieron diferencias estadísticamente significativas en el contenido de CTT entre los sitios, con excepción de EM (igualdad de varianza; ρ = 0,018), pero sí entre los periodos de lluvia y sequía (ρ = 0,027; ρ = 0,029) y en el cuarto trimestre en VF (ρ = 0,000), los mayores registros se encuentran relacionados con DB y CG, así como en las zonas más cercanas a los centros urbanos o de explotación agrícola.