Water Microbiology

Brackish water and fish samples of River Nile in Damietta city were examined. Morphological examination of fish obtained from brackish water of River Nile was examined. The highest value of BOD 5 20 was found during summer being 17.4 mgO 2 /L while the lowest value was found during winter being 9.9 mgO 2 /L. Stannum and arsines did not present in all examined seasons of all samples (water and fish). Lead did not detected in all seasons samples except in spring being 0.003 and 0.003 ppm in water and fish, respectively. The highest value of total bacterial count in brackish water was found during summer being 4300cfu/ml x 10 3 , while the lowest value was in winter being 2 cfu/ml x 10 3. The highest value of total fungal count was in summer being 18 while lowest value was in the winter being 0.8cfu/ml x 10 3. There was no bacterial growth on SS agar medium. The highest value of Staphylococci count was in summer being 30cfu/ml x 10 3. The highest value of Aeromonas count in summer is 50cfu/ml x 10 3. The highest value of coliform count was in spring being 150cfu/ml x 10 3. The total bacterial count of fish muscles were 9, 1600, 0.0 and 0.0cfu/ml x 10 3 in spring, summer, autumn and winter, respectively. On the other hand, the highest value of total bacterial count of fish intestine was 3000 cfu/ml x 10 3 in spring, but the lowest value was in the autumn being 0.1cfu/ml x 10 3. Total bacterial count of fish surface was 390, 1000, 0.1 and 1cfu/ml x 10 3 in spring, summer, autumn and winter, respectively. The highest values of fungal count in muscles, intestine and fish surface were during summer, spring, being 1600, 3000 and 1000 cfu/g x 10 3 , respectively. Ahigh correlation coefficient value (r = 0.747) between the log of total bacterial count (LTBC) and BOD in the brackish water of River Nile was indicated, which means there are a highly pollution in river ecosystem by industrial pollutants. Among 18 bacterial isolates, only 4 were coccoid shape, 5 isolates were short rods and 9 isolates were long rods. 5 isolates were Gram negative and 13 isolates were Gram positive. 9 isolates were spore formers and 9 isolates were non spore formers. All isolates gave negative results in acid fast stain. Staphylococcus sp., Micrococcus sp., Bacillus sp., Esherichia sp. Aspergillusglaucus, A. niger and A. flavus were isolated and identified from water and fish.

Mediterranean sea water and fish samples of Ras El-Bar city in Damietta governorate, Egypt were examined. Morphological examination of fish obtained from sea water was examined. The highest value of BOD 5 20 was found during summer being 2.4

Water and fish samples were collected in three replicates from the same site of Manzala lake water of El-Roda city in Damietta Governorate, Egypt were examined. Morphological examination of fish obtained from Manzala lake water was examined. The highest value of BOD 5 20 was found during summer being 14.8 mgO 2 /L while the lowest value was found during winter being 7.6 mgO 2 /L. Arsines and Stannum did not present in all examined seasons of all samples (water and fish). Lead did not detected in all seasons samples except in spring being 0.003 and 0.003 ppm in water and fish, respectively. Also, cadmium and cupper did not presented in all fish samples. Lead did not detected in spring and summer samples while the highest value was during winter being 0.007 ppm in water and 0.032 ppm during autumn in fish. The highest value of total bacterial count in Manzala lake water was found during spring being 4400 cfu/ml ×10 3 , while the lowest value was in autumn. The highest value of total fungal count was in summer being 22500 cfu/ml ×10 3 while lowest value was in the winter being 0.06 cfu/ml ×10 3. There were no bacterial growth on SS agar medium. The highest value of Staphylococci count was in spring being 1760 cfu/ml ×10 3. The highest value of Aeromonas count in spring being 66 cfu/ml×10 3. The highest value of coliform count was in spring being 1210 cfu/ml×10 3. The total bacterial count of fish muscles were 17.6, 6000, 0.06 and 45 cfu/g ×10 3 in spring, summer, autumn and winter, respectively. On the other hand, the highest value of total bacterial count of fish intestine was 46200 cfu/g ×10 3 in spring, but the lowest value was in the autumn. Total bacterial count of fish surface were 1980, 500, 0.2 and 10 cfu/g ×10 3 in spring, summer, autumn and winter, respectively. The highest values of fungal count in muscles, intestine and fish surface being 1.87, 13200 and 46.2 cfu/g ×10 3 during spring, respectively. The highest values of Staphylococcal counts of fish muscles, intestine and fish surface were in spring being 0.198, 33 and 77 cfu/g ×10 3. The highest count of Aeromonas sp. was in fish intestine during spring, being 2530 cfu/g ×10 3. Coliform was found in the highest values in spring being 1210000 cfu/g ×10 3 in intestine, and the lowest values in the autumn and winter. There was no correlation coefficient (r = 0.00) between the log of total bacterial count and BOD 5 20 in the Manzala lake water. Among 19 bacterial isolates, only one was coccoid shape, 13 isolates were short rods and 5 isolates were long rods. Thirteen isolates were Gram negative and 6 isolates were Gram positive. Six isolates were spore formers and 13 isolates were non spore formers. All isolates gave negative results with acid fast stain. Micrococcus sp., Aeromonas sp., Esherichia sp., Pseudomonas sp., Aspergillus alliaceus, Aspergillus niger, Aspergillus flavus and Penicillium sp. were isolated and identified from water and fish.

Biofilm formation by Aeromonas hydrophila in the food industry poses significant challenges to food safety and quality. Therefore, this comprehensive review aimed to provide insights into the mechanisms and key factors influencing A. hydrophila biofilm formation. It explores the molecular processes involved in initial attachment, microcolony formation, and biofilm maturation; moreover, it concurrently examines the impact of intrinsic factors, including quorum sensing, cyclic-di-GMP, the efflux pump, and antibiotic resistance, as well as environmental conditions, such as temperature, nutrient availability, and osmotic pressure, on biofilm architecture and resilience. Furthermore, the article highlights the potential of bibliometric analysis as a promising method for conceptualizing the research landscape of and identifying knowledge gaps in A. hydrophila biofilm research. The findings underscore the requirement for focused interventions that prevent biofilm development and raise food sector safety. The consolidation of current information and incorporation of bibliometric analysis enhances existing understanding of A. hydrophila biofilm formation and offers insights for future research and control strategies within a food industry context.

Water samples were collected from different sites at Damietta City for both microbiological and physico-chemical examinations during winter 2018. The microbiological results showed that virally investigated types including Poliovirus type 1, Rotavirus, HAV type IB, and H9N2 avian influenza were absent in all examined samples during winter 2018. The highest mean values of total bacterial and total fungal counts in SD and SA sites were 251.333 and 112.667 cfu/ml, respectively. There was no bacterial growth on MacConkey broth, Salmonella Shigella (SS) and Staph-110 agar media. Algae in the SA and SD sites showed the highest quantities, both motile and non-motile species were found. There was no species of protozoa in all examined sites except SA and SD sites which showed few motile ones. Obtained results of physico-chemical parameters, showed the pH values varied between 7.46 in AF site and 7.96 in SD site. Temperature also, varied between 21 and 22.4°C in EA and SD sites. The highest values of COD and BOD5 20 were in SeA and SD sites and were 9.6 and 18.9 mgO2/L, respectively. In case of heavy metals, results showed that the highest values of aluminum, cadmium, iron, nickel, lead, manganese, zinc, copper and chromium were in FD,FA,SD,SD,EA,SA, SD,SeA and SD sites and were 0.13,0.019,0.117,0.054,0.046,0.030,0.387,0.007 and0.014 ppm, respectively. So, these results proved that water sources are in agreement with the ES for using of this water for human purposes.

The aim of this study was to evaluate if a model describing the efflux and the influx of C through the root surface could be fitted to experimental short-term kinetics of carbon (C) exudation by individual apical root segments in maize (Zea mays L.). The efflux of C was set constant or modelled by a power function of the distance from the apex to simulate the greater release of C around the root tip commonly reported in the literature. The influx was proportional to the C concentration in the external solution to simulate the active re-uptake of exudates by the root. Plants were exposed to full light or to shade to manipulate C allocation to roots. The model with a constant efflux gave satisfactory fits to the kinetics of exudation (average R 2 =0.66). The average gross efflux was then 2.1 mg C cm 22 root surface h 21 . The model was improved if exudation was set more intense towards the root apex (average R 2 =0.74). The estimated gross efflux decreased then from 5.2 mg C cm 22 h 21 at the apex to 1.8 mg C cm 22 h 21 for the region located 5-25 cm from the root tip. The decrease in net exudation of individual roots due to the shading of plants was weak, which may indicate that the import of C by the primary roots studied was not reduced significantly. By describing the exudation of an apical root segment of variable length and diameter, the model is a first step in linking exudation to root system architecture models and to whole plant functioning.

Members of the genus Ranavirus (family Iridoviridae) can cause catastrophic mortality of pond-breeding amphibians and are associated with an emerging infectious disease that may be contributing to amphibian declines. We conducted three experiments to examine factors that may affect transmission both within and between local breeding populations of the wood frog (Rana sylvatica). In a laboratory study, when exposed to moribund tadpoles collected during a local ranaviral die-off, uninfected tadpoles died as soon as 4 days after exposure. The onset of death was accelerated when tadpoles were allowed to scavenge on carcasses of infected tadpoles. In a mesocosm experiment that was conducted in outdoor wading pools, die-offs of tadpoles began approximately 19 days after infected tadpoles were added to pools containing uninfected tadpoles. Mass die-offs with greater than 98% mortality occurred in all pools, regardless of the initial tadpole density. In a second mesocosm experiment, the addition of water and bottom sediments that were collected from a pond during a ranaviral die-off did not result in lower tadpole survival or growth relative to controls. Only a small percentage of tadpoles appeared to be sick, and most tadpoles survived until the first individuals began metamorphosing within a pool. However, tests for ranavirus using polymerase chain reaction were positive for most pools that received contaminated sediment, suggesting that some infections were sublethal. Our results indicate that transmission within ponds is enhanced by scavenging and that spread between local ponds could occur via the transport of contaminated sediment by animals or humans.

Commercial poultry farms (n° 523), located in all the six regions of Nigeria were sampled with a view to generate baseline information about the distribution of Salmonella serovars in this country. Five different matrices (litter, dust, faeces, feed and water) were collected from each visited farm. Salmonella was isolated from at least one of the five matrices in 228 farms, with a farm prevalence of 43.6% (CI95[39.7-48.3%]). Altogether, 370 of 2615 samples collected (14.1%, CI95[12.8; 15.5%]) contained Salmonella. Considering the number of positive farms and the number of positive samples, it was evident that for the majority of the sampled farms, few samples were positive for Salmonella. With regard to the matrices, there was no difference in Salmonella prevalence among the five matrices considered. Of the 370 isolates serotyped, eighty-two different serotypes were identified and Salmonella Kentucky was identified as having the highest isolation rate in all the matrices sampled (16...

It is hereby notified that no part of this thesis maybe reproduced, stored in a retrieval system, or transmitted, in any form by any means, electronic, mechanical, photocopying, recording or otherwise, without prior consent of the author, except for academic purposes. iv CERTIFICATE OF COMPLETION OF DISSERTATION I, Luke John Banda, do hereby certify that this dissertation is the product of my own work and, in submitting it for my MPH (Environmental Health) programme further attest that it has not been submitted in part or in whole to another University. Signature: _________________________ Date: _______________________ Supervisors: I, Allan R. Mbewe, Having submitted and read this dissertation, I am satisfied that this is the original work of the author under whose name it is being presented. I, therefore, confirm that the worker has been completed satisfactorily and is hereby ready for presentation to the examiners. Signature: ______________________ Date: ________________________ I, Dr. S. H. Nzala, Having submitted and read this dissertation, I am satisfied that this is the original work of the author under whose name it is being presented. I confirm that the worker has been completed satisfactorily and is hereby ready for presentation to the examiners. Signature: ____________________ Date: ___________________________ I, Dr. H. Halwindi, Having submitted and read this dissertation, I am satisfied that this is the original work of the author under whose name it is being presented. I, therefore, confirm that the worker has been completed satisfactorily and is hereby ready for presentation to the examiners.

Poliovirus 1 was inactivated by free chlorine at pH 9.0 three times more rapidly in boric acid (0.05 M)-NaOH buffer than in purified (carbon-filtered, deionized) water. Thus, at a given concentration of free chlorine, it took three times longer to inactivate the same fraction of the poliovirus in purified water than in the boric acid-NaOH buffer. Conversely, in a given period of time, three times more chlorine was required to inactivate a given percentage of the virus in purified water than in the boric acid-NaOH buffer. Buffers are almost always used to control pH in disinfection studies with free chlorine and with other chlorine compounds also. The use of buffers for pH control in such disinfection studies may distort the resulting data and, at least for waters that contain little salt, may cause serious overestimation of the rates at which viruses are inactivated.

SUMMARYCampylobacteris the most prevalent cause of bacterial gastroenteritis worldwide and it represents a significant public health risk of increasing severity due to its escalating resistance to clinically important quinolone and macrolide antibiotics. As a zoonotic pathogenCampylobacteris transmitted along the food chain and naturally cycles from environmental waters, feedstuff, animals and food to humans. We determined antibiotic resistance profiles, as well as multilocus sequence types andflaA-SVR types for 52C. jejuniisolated in Slovenia from human, animal, raw and cured chicken meat and water samples. Twenty-eight different sequence types, arranged in ten clonal complexes, three new allele types and five new sequence types were identified, indicating the relatively high diversity in a small group of strains. The assignment of strains from different sources to the same clonal complexes indicates their transmission along the food supply chain. The most prevalent clonal complex ...

Several studies have revealed that dental unit waterlines (DUWLs) are often contaminated by large numbers of various micro-organisms (bacteria, fungi, protozoa, viruses). Microbial contamination in DUWLs may originate from the mains water piped into the dental unit, the suck-back of patients' saliva into the line due to the lack of adequate valves, and contamination from bottled water systems. Some of the main determinants of microbial contamination in DUWLs are: a very small lumen size (0.5-2 mm) of the tubing used, high surface-to-volume ratio (6:1), low throughput and the materials of which the tubing is made, water stagnation outside of working hours. The environmental conditions present inside the conduits of the dental unit may facilitate the proliferation of micro-organisms and the consequent formation of biofilm on the interior surface of the pipes of DUWLs. During the use of handpieces, particularly high-speed rotating instruments, a spray is thrown up in the form of aerosols or spatters containing biological material (saliva, blood and dental plaque) and micro-organisms. This means that the health of both dental staff and patients could be at risk of infection. The risk of cross-infections in dental settings can be tackled by implementing combined interventions to prevent the contamination of DUWLs.

Viruses which formed plaques on lawns of a eucaryotic, chlorella-like green alga were detected in 37% of the 35 freshwater samples surveyed. Virus populations, monitored in seven locations, fluctuated both qualitatively and quantitatively over an 8-month period. Viruses which infect cyanobacteria (blue-green algae) are common in nature (e.g., see references 4 and 5), and some of these viruses have been characterized in detail (6). In contrast, little information is available on viruses or virus- like particles which infect eucaryotic algae (for reviews, see references 1-3, 6). Most viruses or virus-like particles in eucaryotic algae have been detected during ultrastructural studies of the algae, and only a few attempts have been made to characterize these particles, primarily because they could not be obtained in sufficient quantities. Several factors account for this problem. (i) Usually only a few algal cells contain particles; (ii) usually the cells only contain particles in one stage of the life cycle; (iii) the cells that have particles may not lyse; and (iv) the particles may not be infectious. All of these factors contribute to the lack of a sensitive biological assay for viruses infecting eucaryotic algae; conse- quently, it is not known how common such viruses are in freshwater environments. Thus, it is interesting that we have identified, isolated, and partially characterized a large (negatively stained particles are ca. 190 nm in diameter) polyhedral virus, PBCV-1, from a eucaryotic chlorella-like green alga symbiotic with the protozoan Paramecium bursaria (11). Subsequent experi- ments established that PBCV-1 infects and replicates in a culturable chlorella-like green alga (strain NC64A) also originally isolated from paramecia (8, 10). PBCV-1 is a complex virus that contains a lipid component, at least 50 structural proteins, and a large (at least 300 kilobase pairs), double-stranded DNA genome . Most importantly, the virus can be assayed by plaque formation, which provides a sensitive biological assay for the virus (8). We recently looked for additional plaque-forming Chlor- ella viruses from natural sources. Twenty freshwater sam- ples were collected from ponds and streams in North and South Carolina, Florida, Nebraska, and Illinois and assayed for viruses. To our surprise, 4 of the 20 samples produced plaques on Chlorella strain NC64A lawns (9). The virus titer in these water samples varied from 60 to 4 x 104 PFU/ml. A few of the plaques were picked from each of the four samples and partially characterized. All of the viruses were similar to PBCV-1 with regard to host range, morphology, and sensitivity to organic solvents. Furthermore, the viruses * Corresponding author. t Paper no. 7664, Journal Series, Nebraska Agricultural Experi- ment Station.

Plaque-forming viruses of the unicellular, eucaryotic, exsymbiotic, Chlorella-like green algae strain NC64A, which are common in the United States, were also present in fresh water collected in the People's Republic of China. Seven of the Chinese viruses were examined in detail and compared with the Chlorella viruses previously isolated in the United States. Like the American viruses, the Chinese viruses were large polyhedra and sensitive to chloroform. They contained numerous structural proteins and large double-stranded DNA genomes of at least 300 kilobase pairs. Each of the DNAs from the Chinese viruses contained 5-methyldeoxycytosine, which varied from 12.6 to 46.7% of the deoxycytosine, and N6-methyldeoxyadenosine, which varied from 2.2 to 28.3% of the deoxyadenosine. Four of the Chinese virus DNAs hybridized extensively with DNA from the American virus PBCV-1, and three hybridized poorly. Reacts with antiserum toa: Virus

Due to the growing resistance of pathogenic bacteria and fungi against commercially available therapeutics, the search for new antimicrobial substances is of increasing importance. Based on the hypothesis that microorganisms living in an aquatic environment produce secondary metabolites as chemical weapons to survive in their daily fight against cohabitants of the biotope, a screening of 133 microalgae (121 cyanobacteria, 12 eukaryotic microalgae) was started. Biomass extracts and cultivation media were tested for activity against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa as well as the yeast Candida maltosa. Our data indicates that 56 cyanobacterial strains and 5 eukaryotic algae exhibited antimicrobial activity. Interestingly, 19 of the screened cyanobacteria inhibited the growth of MRSA. Further, screening experiments revealed activity against Helicobacter pylori as well as fish p...

The ‘H2S test’ is being advanced for microbiological water quality testing where conventional coliform based methods are impractical or too expensive. It involves ambient temperature incubation of water samples with nutrient formulated to generate hydrogen sulphide when ‘faecal’ bacteria are present. Recently a WHO review identified several concerns including the limited number of comparative studies, formulation variability, and false positives and negatives. In response we have compared the H2S test's ability to detect and quantify faecal contamination in an aquifer impacted by septic tank leachfields with measurements obtained concurrently using conventional bacterial indicators, coliphages, faecal sterol biomarkers, Cryptosporidium and Giardia. Like these other analytes, H2S testing detected a contamination gradient ranging from high (septic liquid) to moderate (exfiltration zones), to background (e.g. domestic bores), corresponding to indicator removal + dilution by factors...

The traditional approach to biochemical identification of marine fresh isolates requires considerably long culture preparation times and large quantities of expensive materials and reagents, and the results are not very reliable. On the other hand, taxonomy tests based on DNA composition, although sensitive and reliable, require long execution times and high costs. A method is presented for the classification of fatty-acid profiles, extracted from marine bacteria strains, at genus level based on supervised artificial neural networks. The proposed method allows the correct identification of all patterns belonging to the training set and almost all patterns belonging to the test set. Moreover, a quantitative measure of the importance of each fatty acid for bacterial classification is also achieved. This measure allows the determination of a cluster of fatty acids to be controlled with greater care. The results show that the proposed method is reproducible and rapid, so that it can be routinely used in the marine microbiology laboratory to identify fresh isolates. T HE MARINE environment is being given increasing attention by biotechnologists in as much as marine microorganisms play an important role in pollution [3], biodeterioration of immersed material [8], biogeochemical processes, and disease . Moreover, marine bacteria comprise a comparatively unlimited reservoir of commercially valuable compounds such as: enzymes, single cell protein, and pharmaceutical compounds . In the last 20 years bacterial taxonomy has obtained increasing success by using biochemical, genetic, and molecular biology concepts. However, marine fresh isolates are still notoriously difficult to identify. The major difficulties found in the traditional approach to biochemical identification are the need for an easily cultivable strain, the considerably long time required for the preparation of cultures, the need for large quantities of expensive materials and reagents, and, finally, the low reliability of results. Possibly, the reason stems from the lack of correspondence between the biochemical features reported in literature for the type strains and the results obtained in Manuscript

The importance of rapidly developing and distributing safe and effective vaccines was a major lesson from the COVID-19 pandemic, which drove new vaccine development technologies. In May 2024, the World Health Organization (WHO) updated the identification of bacterial pathogens of importance to public health as guidance for research and development of strategies to prevent and overcome global antimicrobial resistance (AMR). In June 2024, the WHO updated the 2017-18 list of priority pathogens to provide a scientific framework for epidemic and pandemic preparedness. The 2024 updated WHO list of priority pathogens also recognizes emerging infections and historical former pandemic infections, including Yersinia pestis, the cause of bubonic, pneumonic, and septicemic plague. Between 2010 and 2019, the six countries with the most reported human cases of Yersinia pestis infection (from highest to lowest) were Madagascar, the Congo, Uganda, Peru, Tanzania, and the USA, with a total of 4,547 cases with a mortality rate of 17% (786 cases). More than 20 candidate plague vaccines are in the preclinical phase, with few in early (phase 1) clinical trials. This editorial highlights the need for continued review of potential pandemic pathogens and the re-emergence of plague, which awaits a vaccine.

A novel filamentous bacterium, designated Nari11AT, was isolated from soil collected from a salt lake named Chott Melghir, located in north-eastern Algeria. The strain is an aerobic, halophilic, thermotolerant, Gram-stain-positive bacterium, growing at NaCl concentrations between 5 and 20 % (w/v) and at 43–60 °C and pH 5.0–10.0. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C17 : 0. The DNA G+C content was 53.4 mol%. ll-Diaminopimelic acid was the diamino acid of the peptidoglycan. The major menaquinone was MK-7, but MK-6 and MK-8 were also present in trace amounts. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and three unidentified phospholipids. Results of molecular and phenotypic analyses led to the description of the strain as a novel member to the genus Melghirimyces , family Thermoactinomycetaceae . Strain Nari11AT shows 96.7 % 16S rRNA gene sequence similarity ...

Mesoscale circulation generated by the Loop Current in the Northern Gulf of Mexico (NGOM) delivers growth-limiting nutrients to the microbial plankton of the euphotic zone. Consequences of physicochemically driven community shifts on higher order consumers and subsequent impacts on the biological carbon pump remain poorly understood. This study evaluates microbial plankton <10 μm abundance and community structure across both cyclonic and anti-cyclonic circulation features in the NGOM using flow cytometry (SYBR Green I and autofluorescence parameters). Non-parametric multivariate hierarchical cluster analyses indicated that significant spatial variability in community structure exists such that stations that clustered together were defined as having a specific 'microbial signature' (i.e. statistically homogeneous community structure profiles based on relative abundance of microbial groups). Salinity and a combination of sea surface height anomaly and sea surface temperature were determined by distance based linear modeling to be abiotic predictor variables significantly correlated to changes in microbial signatures. Correlations between increased microbial abundance and availability of nitrogen suggest nitrogenlimitation of microbial plankton in this open ocean area. Regions of combined coastal water entrainment and mesoscale convergence corresponded to increased heterotrophic prokaryote abundance relative to autotrophic plankton. The results provide an initial assessment of how mesoscale circulation potentially influences microbial plankton abundance and community structure in the NGOM.

The growing threat of antimicrobial resistance of human and animal origin has become a major global public health challenge in the treatment of microbial infections. The discovery and development of novel drugs such as Quorum Sensing (QS) inhibitors are urgently needed to mitigate this problem, which has greatly undermined the clinical effectiveness of conventional antibiotics. QS Systems, which are cell-to-cell communications among bacteria, allow bacteria to adapt rapidly to unfavourable conditions in their environment, promoting the formation of antibiotic-tolerant biofilm communities. It is well known that QS enhances the recalcitrant mode of growth in biofilm formation and also increases bacterial resistance and virulence to conventional antibiotics. QS inhibitors can eliminate the QS signals and hinder biofilm formation, reduce bacterial virulence and prevent antimicrobial resistance by the pathogens. Natural, semi-synthetic and synthetic inhibitors have been identified as potential QS inhibitors in which synthetically modified QS inhibitors with lactone moieties can be designed as an alternative to conventional antibiotics. This review will expand drug design researchers and pharmaceutical companies knowledge base on the development of synthetically modified QS inhibitors and their applicability in treatment.

ObjectiveIn urban Dhaka, Bangladesh, 30% of source water samples collected from the households of patients with cholera had detectable Vibrio cholerae. These findings indicate an urgent need for a public health intervention for this population. The Crystal VC® dipstick test is a rapid method for detecting V. cholerae in stool and water. However, to date no study has investigated the use of the rapid dipstick test for household surveillance of stored drinking water.MethodsThe efficacy of the Crystal VC® dipstick test for detecting V. cholerae in the Dhaka city municipal water supply and stored household drinking water sources after enrichment for 18 h in alkaline peptone water (APW) was compared to bacterial culture as the gold standard.ResultsA total of 1648 water samples (824 stored household drinking water samples and 824 municipal water supply samples) were collected from households of patients with cholera. The overall specificity and sensitivity of the dipstick test compared to...

Drinking water treatment plants rely on purification of contaminated source waters to provide communities with potable water. One group of possible contaminants are enteric viruses. Measurement of viral quantities in environmental water systems are often performed using polymerase chain reaction(PCR) or quantitative PCR (qPCR). However, these results can often be underestimated due to challenges involved in a multi-step viral concentration process and PCR inhibition. In this study, water samples were concentrated from 25 drinking water treatment plants (DWTPs) across the US to study the occurrence of enteric viruses in source water and removal after treatment. The five different types of viruses studied were adenovirus, norovirus GI, norovirus GII, enterovirus, and polyomavirus. Quantitative PCR was performed on all samples to determine presence or absence of these viruses in each sample. Ten DWTPs showed presence of one or more viruses in source water, with four DWTPs having treated drinking water testing positive. Furthermore, PCR inhibition was assessed for each sample using an exogenous amplification control, which indicated that all of the DWTP samples, including source and treated water samples, had some level of inhibition, confirming that inhibition plays an important role in PCR based assessments of environmental samples. PCR inhibition measurements, viral recovery, and other assessments were incorporated into a Bayesian model to more accurately determine viral load in both source and treated water. Results of the Bayesian model documented that viruses are present in source water and treated water. By using a Bayesian framework that incorporates inhibition, as well as many other parameters that affect viral detection, this study offers an approach for more accurately estimating the occurrence of viral pathogens in environmental waters.

An occurrence survey was conducted on selected pathogens in source and treated drinking water collected from 25 drinking water treatment plants (DWTPs) in the United States. Water samples were analyzed for the protozoa Giardia and Cryptosporidium (EPA Method 1623); the fungi Aspergillus fumigatus, A. niger and A. terreus (quantitative PCR [qPCR]); and the bacteria Legionella pneumophila (qPCR), Mycobacterium avium, M. avium subspecies paratuberculosis, and M. intracellulare (qPCR and culture). Cryptosporidium and Giardia were detected in 25% and in 46% of the source water samples, respectively (treated waters were not tested). Aspergillus fumigatus was the most commonly detected fungus in source waters (48%) but none of the three fungi were detected in treated water. L. pneumophila was detected in 25% of the source water samples but in only 4% of treated water samples. M. avium and M. intracellulare were both detected in 25% of source water, while all three mycobacteria were detected in 36% of treated water samples. Five species of mycobacteria, M. mucogenicum, M. phocaicum, M. triplex, M. fortuitum, and M. lentiflavum were cultured from treated water samples. Although these DWTPs represent a fraction of those in the U.S., the results suggest that many of these pathogens are widespread in source waters but that treatment is generally effective in reducing them to below detection limits. The one exception is the mycobacteria, which were commonly detected in treated water, even when not detected in source waters.

16S rRNA-targeted in situ hybridization combined with confocal laser scanning microscopy was used to elucidate the spatial distribution of microbes within two types of methanogenic granular sludge, mesophilic (35°C) and thermophilic (55°C), in upflow anaerobic sludge blanket reactors fed with sucrose-, acetate-, and propionate-based artificial wastewater. The spatial organization of the microbes was visualized in thin sections of the granules by using fluorescent oligonucleotide probes specific to several phylogenetic groups of microbes. In situ hybridization with archaeal- and bacterial-domain probes within granule sections clearly showed that both mesophilic and thermophilic granules had layered structures and that the outer layer harbored mainly bacterial cells while the inner layer consisted mainly of archaeal cells. Methanosaeta -, Methanobacterium -, Methanospirillum -, and Methanosarcina -like cells were detected with oligonucleotide probes specific for the different groups o...

A thermophilic and hydrogenotrophic methanogen, strain RMAST, was isolated from gas-associated formation water of a gas-producing well in a natural gas field in Japan. Strain RMAST grew solely on H2/CO2 but required Casamino acids, tryptone, yeast extract or vitamins for growth. Growth of strain RMAST was stimulated by acetate. Cells were non-motile, straight rods (0.5×3.5–10.5 µm) and occurred singly or in pairs. Bundles of fimbriae occurred at both poles of cells and the cell wall was thick (approximately 21 nm, as revealed by ultrathin section electron microscopy). Strain RMAST grew at 45–80 °C (optimum, 70 °C), at pH 5.8–8.7 (optimum, pH 6.9–7.7) and with 0.001–20 g NaCl l−1 (optimum, 2.5 g NaCl l−1). Phylogenetic analysis revealed that Methanothermobacter thermautotrophicus ΔHT was most closely related to the isolate (95.7 % 16S rRNA gene sequence similarity). On the basis of morphological, phenotypic and phylogenetic characteristics, it is clear that strain RMAST represents a ...

Accurate diagnosis and proper treatment of infectious diseases in the early stages are essential in preventing financial losses and patient suffering. Advanced diagnostic tests e.g. ELISA, CFT, PCR etc. are very costly, cumbersome, require sophisticated equipment and skilled personnel and cannot be employed at field level. Bacteriophages are viruses that specifically infect bacteria, replicate in it and lyse it. Lysis of the bacteria can be detected by using suitable indicator system. By employing bacteriophages along with indicator systems, accurate, easy and cost effective diagnosis of bacterial pathogens is possible in field conditions. Phage based diagnostic methods are cheap, simple and highly specific for bacterial diseases and are of bedside and penside applicability. Phage based diagnostics employing phage amplification and phage plaque method, reporter genes for luminescence, Fluorescence assays, MTT assay, Adenylate Kinase assay and ATP assay have been described here.

Application of manure or soil amendments of animal origin (untreated soil amendments; UTSAs) to agricultural land has been a long-standing practice to maintain or improve soil quality through addition of organic matter, nitrogen, and phosphorus. Much smaller quantities of these types of UTSAs are applied to land used for food crops than to land used for animal grain and forage. UTSAs can harbor zoonotic enteric pathogens that may survive for extended periods after application. Additional studies are needed to enhance our understanding of preharvest microbial food safety hazards and control measures pertaining to the application of UTSAs especially for land used to grow produce that may be consumed raw. This document is intended to provide an approach to study design and a framework for defining the scope and type of data required. This document also provides a tool for evaluating the strength of existing data and thus can aid the produce industry and regulatory authorities in identi...

Data from ice 3590 meters below Vostok Station indicate that the ice was accreted from liquid water associated with Lake Vostok. Microbes were observed at concentrations ranging from 2.8 × 10 3 to 3.6 × 10 4 cells per milliliter; no biological incorporation of selected organic substrates or bicarbonate was detected. Bacterial 16 S ribosomal DNA genes revealed low diversity in the gene population. The phylotypes were closely related to extant members of the alpha - and beta - Proteobacteria and the Actinomycetes. Extrapolation of the data from accretion ice to Lake Vostok implies that Lake Vostok may support a microbial population, despite more than 10 6 years of isolation from the atmosphere.

Laguna de Pozuelos is an extensive wetland in Morthwestern Argentina at 3,600 m above sea level in the Argentinean Andes. The principal lake, placed in the central depression of endorheic basin, is rich in minerals like Cu, As, Fe, etc. It collects water from underground courses and from two main tributaries, namely Santa Catalina River to the north and Cincel River to the south. Following the dry and rainy seasons, the surface of the lake is subject to an annual contraction-expansion cycle, with increasing of salinity during evaporation period. Prokaryotes inhabitants these particular environments have been not described and a few of such places have been surveyed for microbial diversity studies. To systematically explore the underlying communities of Bacteria from the water lake of Laguna de Pozuelos wetland and Cincel River, bacterial 16S rRNA genes (rDNAs) were PCR amplified and analyzed by terminal restriction fragment length polymorphism (T-RFLP) analysis. Analysis of the micr...

We investigated the temporal and vertical changes in the microbial communities related to hydrological variations an aquifer (Brittany, France). Five water samplings were carried out, spanning three hydrological cycles in the variably and the permanently saturated zones. Seasonal variations in the major anion concentrations (NO À 3 , SO 2 4 À and Cl À ) indicated that different physical processes occurred during the recharge process in the two zones. The variably saturated zone is mainly dominated by diffusion and advection processes from the soil, whereas the permanently saturated zone is controlled by moderate advective transfer from the variably saturated zone. Bacterial diversity was investigated by flow cytometry, 16S rRNA and narG genes analyses. Part of this diversity was new in that 6 of the 27 16S rRNA gene sequence phylotypes were unknown even at the class or phylum level. The narG gene analysis did not reveal any clear variation in time or depth within the nitrate reducers' community. In contrast, 16S rRNA gene analyses showed modifications of community composition that could be related to the hydrologic and chemical contrast between the two zones. It was concluded that the physical processes of water transfer could influence bacterial diversity at the soil-aquifer interface.

Population pollution are continous growth leading to scarcity of natural resources like water,Coal,Disel and Petroleum Destruction of forest, Natural habitat of animals and Humans. Growing strength of Building ,Industries , habitans and Transportation vehicles contributing to green house gases leading to climate change .Energy security and climate change are both global challenges. In order to end energy crises and to combat global warming Scientist are begning to look to Biofuels as a replacement of energy source .According to DOE(Department of energy gov of USA has reported that algae yields 30 times more energy per acre than land crops keeping earth clean and free from pollution .Climatic conditions of the country is favourable for this alternative source of energy as it has abudant fresh water resources excellent weather sunshine make it a prime location. Baramati is rich and diverse bio resources of this region are yet to be explored for their potential biotechnological application region Baramati experiences hot summers from march to may weather is dry and hot in summer ,it is usual that day temperature crossing 40.c mark it is good for growth of algae survey on algal samples collection was carried out of Nira left bank canal Baramati to study the density and diversity of phytoplankton .Water samples were collected from two different sites of Nira left bank canal for a period of year with the help of plankton net .Samples were collected between 9am to 11am at a depth of 0.50 m at both the location from different season summer ,winter and rainy .The collected samples were placed in sedwig rafter cell slide and observed under Binocular microscope .The observed algae were identified using standard identification method .The quantitative estimation was done to determine frequency density and abundance of scenedesmus common counting is lackey drop method.

Determining the applicability of a wastewater treatment procedure is dependent on its efficiency and cost-effectivity. The main objective of this study is to establish the reusability of Fe-modified MMT nanomembrane when utilized as adsorbent material for wastewaters containing mercury in complex with cyanide in aqueous solutions. Three cycles of adsorptionelution runs were done on the nanomembranes and the mercury (Hg) concentrations in the wastewaters (initial, after adsorption, after elution) were analyzed using HD XRF. Results showed that there was no substantial difference in the adsorption efficiencies for the first two (2) cycles (37.61% and 35.69%). Using 0.01M acetic acid as eluate, the nanomembranes were observed to be reusable twice before the nanomembranes become extensively degraded. In addition, precipitation was employed to retrieve the Hg from the eluates. One (1) g as-received and grinded (150-500μm) sodium thiosulfate (Na 2 S 2 O 3) precipitants were used and it was established that, after 24 h, the precipitant with finer particle sizes was able to retrieve higher amounts of Hg (as-received:59% vs grinded:87.27%). Moreover, increasing the amount of the grinded Na 2 S 2 O 3 to 5g resulted to better Hg recovery (89.47%). Further analysis on the derived precipitates also confirmed the presence of Hg (19.90ppm for red precipitates; 24.73ppm for black precipitates).

Five nonradioactive probe assays were evaluated by using chemiluminescent and colormetric signals, along with two isotopic assays and cell culture, for the detection of poliovirus in concentrated water samples. In environmental samples, a 100% correlation existed between digoxigenin and single-stranded [32P]RNA probes. All probe assays detected more positive samples than the cell culture did.

The survival of selected hygienically relevant bacterial species in activated carbon (AC) filters on a bench scale was investigated. The results revealed that after inoculation of the test strains the previously sterilized AC adsorbed all bacteria (106 to 107). After a period of 6 to 13 days without countable bacteria in the effluent, the numbers of Escherichia coli, Pseudomonas aeruginosa, and Pseudomonas putida increased up to i04 to i05 CFU/ml of effluent and 106 to 107 CFU/g of AC. When Kkebsiella pneumoniae and Streptococcus faecalis were * Corresponding author.

The aim of this investigation was to assess the startup and operation of a laboratory-scale hybrid UASB-Anaerobic Filter Reactor (UASFB) of 1 L volume, kept at 30°C, in order to carry out a simultaneous autotrophic and heterotrophic denitrification process. First, the heterotrophic and autotrophic populations were separately enriched, with specific cultures and subsequently the UASFB was inoculated with 2 g L(-1) of volatile suspended solids (VSS), with a ratio of 1.5:1 (autotrophs: heterotrophs). The influent or synthetic wastewater used was composed of: Na2S2O3·5H2O, CH3COOK, NaNO3, NaHCO3, K2HPO4, NH4Cl and saline solution. The concentrations varied depending on the organic loading rate (OLR), nitrogen loading rate (NLR) and sulfur loading rate (SLR) applied. In the UASFB reactor, two experimental conditions were tested and assessed: (i) COD/N ratio of 3.6 and SLR of 0.75 kg S m(-3) d(-1); and (ii) COD/N ratio of 5.8 and SLR of 0.25 kg S m(-3) d(-1). The results obtained demonstr...

We investigated the distribution and activity of chloroethene-degrading microorganisms and associated functional genes during reductive dehalogenation of tetrachloroethene to ethene in a laboratory continuousflow column. Using real-time PCR, we quantified "Dehalococcoides" species 16S rRNA and chloroethenereductive dehalogenase (RDase) genes (pceA, tceA, vcrA, and bvcA) in nucleic acid extracts from different sections of the column. Dehalococcoides 16S rRNA gene copies were highest at the inflow port [(3.6 ؎ 0.6) ؋ 10 6 (mean ؎ standard deviation) per gram soil] where the electron donor and acceptor were introduced into the column. The highest transcript numbers for tceA, vcrA, and bvcA were detected 5 to 10 cm from the column inflow. bvcA was the most highly expressed of all RDase genes and the only vinyl chloride reductase-encoding transcript detectable close to the column outflow. Interestingly, no expression of pceA was detected in the column, despite the presence of the genes in the microbial community throughout the column. By comparing the 16S rRNA gene copy numbers to the sum of all four RDase genes, we found that 50% of the Dehalococcoides population in the first part of the column did not contain either one of the known chloroethene RDase genes. Analysis of 16S rRNA gene clone libraries from both ends of the flow column revealed a microbial community dominated by members of Firmicutes and Actinobacteria. Higher clone sequence diversity was observed near the column outflow. The results presented have implications for our understanding of the ecophysiology of reductively dehalogenating Dehalococcoides spp. and their role in bioremediation of chloroethenes.

Floodwaters in New Orleans from Hurricanes Katrina and Rita were observed to contain high levels of fecal indicator bacteria and microbial pathogens, generating concern about long-term impacts of these floodwaters on the sediment and water quality of the New Orleans area and Lake Pontchartrain. We show here that fecal indicator microbe concentrations in offshore waters from Lake Pontchartrain returned to prehurricane concentrations within 2 months of the flooding induced by these hurricanes. Vibrio and Legionella species within the lake were more abundant in samples collected shortly after the floodwaters had receded compared with samples taken within the subsequent 3 months; no evidence of a long-term hurricane-induced algal bloom was observed. Giardia and Cryptosporidium were detected in canal waters. Elevated levels of fecal indicator bacteria observed in sediment could not be solely attributed to impacts from floodwaters, as both flooded and nonflooded areas exhibited elevated l...

New approaches should be considered as the US Environmental Protection Agency (EPA) moves rapidly to develop new beach monitoring guidelines by the end of 2012, as these guidelines serve as the basis by which states and territories with coasts along the oceans and Great Lakes can then develop and implement monitoring programs for recreational waters. We describe and illustrate one possible approach to beach regulation termed as the “Comprehensive Toolbox within an Approval Process (CTBAP).” The CTBAP consists of three components. The first is a “toolbox” consisting of an inventory of guidelines on monitoring targets, a series of measurement techniques, and guidance to improve water quality through source identification and prevention methods. The second two components are principles of implementation. These include first, “flexibility” to encourage and develop an individualized beach management plan tailored to local conditions and second, “consistency” of this management plan to en...

Aims: Research into the relationship between pathogens, faecal indicator microbes and environmental factors in beach sand has been limited, yet vital to the understanding of the microbial relationship between sand and the water column and to the improvement of criteria for better human health protection at beaches. The objectives of this study were to evaluate the presence and distribution of pathogens in various zones of beach sand (subtidal, intertidal and supratidal) and to assess their relationship with environmental parameters and indicator microbes at a non-point source subtropical marine beach. Methods and Results: In this exploratory study in subtropical Miami (Florida, USA), beach sand samples were collected and analysed over the course of 6 days for several pathogens, microbial source tracking markers and indicator microbes. An inverse correlation between moisture content and most indicator microbes was found. Significant associations were identified between some indicator microbes and pathogens (such as nematode larvae and yeasts in the genus Candida), which are from classes of microbes that are rarely evaluated in the context of recreational beach use. Conclusions: Results indicate that indicator microbes may predict the presence of some of the pathogens, in particular helminthes, yeasts and the bacterial pathogen Staphylococcus aureus including methicillin-resistant forms. Indicator microbes may thus be useful for monitoring beach sand and water quality at non-point source beaches. Significance and Impact of the Study: The presence of both indicator microbes and pathogens in beach sand provides one possible explanation for human health effects reported at non-point sources beaches.

We debate molecular (qPCR) versus culture-based tools for monitoring of bathing waters -We identify concerns surrounding the use of qPCR for bathing water regulation -Modelling may offer a more useful 'rapid method' for informing on bathing water quality

Good quality drinking water is essential for human physiology and perpetual existence but the availability remains a challenge most especially in developing countries. As a result of increase in population growth, local effort to satisfy its potable services has been taken over by private sectors, selling it in packaged plastic sachets. The need to ascertain both microbiological and physicochemical quality in order to determine safety become paramount. Ten different brands of sachet water were collected at random at the first instance of five visits and then another 10 samples were collected at the second instance of visit within Dutse metropolis. They were analyzed for physical/organoleptic and some physicochemical properties including total dissolve solids (TDS: 30.60-162.00mg/L), conductivity (27.00-453(µscm -), salinity (11.07-186.4mg/l), hardness (8.05-7.04mg/l), alkalinity (09-82mg/l), temperature , chloride (0.00-0.02mg/l) and laminate thickness (0.032-0.065mm). They were all within the specifications for drinking water quality by World Health Organization (WHO) and National Agency for Food, Drug Administration (NAFDAC) and other regulatory bodies. This indicated high level of conformity to specified standard procedures in treatment, packaging, storage, and distribution. These might lead to significant decrease in waterborne illnesses (non-infectious) in Dutse metropolis. It is highly recommended that these manufacturers of sachet water should keep on maintaining good standard of quality in order to safeguard public health.

ZnO nanorods (ZnO NRs) were grown on ZnO seeded fluorine doped tin oxide (FTO) substrates at low temperatures (90 °C) from Zn2+ precursors in alkaline aqueous solution. The ZnO seeds were deposited on the FTO substrate heated at 350 °C by spray pyrolysis of a zinc acetate solution in a water ethanol mixture. The structure of seeds was tuned by the ethanol water ratio, Γ, which controls the solvent evaporation rate of drops impinging the substrate. The relationship between the microstructure and optical properties of the ZnO NR films and the photocatalytic antibacterial activity for Escherichia coli abatement, was determined through a detailed characterization of the material. The higher photocatalytic antibacterial activity was performed by ZnO NR films grown on seeds deposited from solutions with Γ in the 0.0–0.03 range. With these films, the population of viable E. coli dropped more than six orders, from 8 × 108 to 4 × 102 CFU. These results show the potential of these materials i...

The effectiveness of 10 low-cost UV-absorbers in protecting Bacillus thuringiensis subsp. kurstaki BLB1 toxins against inactivation by UV-A and UV-B irradiation was evaluated in this study. Among them, two by-products, molasses and olive mill wastewater (OMW) were selected for further studies. They were tested at different concentrations of 0.05, 0.1, 0.15 and 0.2% using the para-aminobenzoic acid (PABA) as a common UV protectant. Interestingly, addition of PABA and OMW to BLB1 formulations was found to be most effective in protecting BLB1 spores at 90.8 and 76.4% respectively and in preserving deltaendotoxin concentration at a level of 81.7 and 72.2%, respectively when used at a concentration of 0.2%. The lowest preserved spores (46.3%) and delta-endotoxin level (12.4%) was found using molasses. In contrast, spore count and delta-endotoxin concentration were completely reduced after an exposure of unprotected Bt strain BLB1 to UV radiations up to 96 h. SDS-PAGE analysis of protected and unprotected samples revealed that delta-endotoxin bands (130, 65-70 kDa) were conserved until 96 h of UV exposure in presence of PABA or OMW compared with their disappearance in presence of molasses after 72 h of exposure and their dramatically decline from 8 h of exposure in unprotected mixture. A complete loss of larvicidal toxicity against Ephestia kuehniella was found after 24 h of exposure in absence of any UVabsorber. Addition of OMW or PABA offered the highest levels of insecticidal activity with 63.2 and 74.7% of residual toxicity, respectively. Whereas, molasses addition, as UV protectant retained only 26.3% of residual activity after 96 h of exposure. Therefore, addition of OMW by-product to Bt formulation may be a suitable alternative to others synthetic chemical compounds. OMW may also provided added value, be environmentally friendly and less hazardous, when used at low concentration.

The overall objective of this part of AQUAREHAB was to develop a semi-passive rehabilitation technology to cope with aqueous pesticide pollution. The basic idea of the rehabilitation technology is to treat the pollutants in open-air trenches that drain contaminated groundwater from the riparian zone and that contain tailored materials as support for microbial biofilms that degrade the pesticides in the contaminated drainage water (Figure 1).

High concentrations of water-borne organisms cause multiple public health problems. Contamination of water exiting the dental unit water lines could be inhibited with the use of some disinfectants. The purpose of this investigation was to establish the effect of two disinfectants and to test their capacity to eliminate colony forming units (CFU) per mL. Vacuum lines of four chairs were treated for a total of 2 weeks. Two disinfectants (Bio Ò 2000 and Alpron Ò ) were used as per manufacturer's instructions. Water samples for hetereothrophic counts from each unit's air ⁄ water syringe line were collected before treating the first patient of the day. Baseline, daily, first and second week samples of 10 mL were plated on blood agar plates and eosin ethylene blue agar. For meosifilic bacterial counts, Mueller Hinton agar plates with 1 mL direct and 1 ⁄ 10 were used in sterile serum and CFU were counted. The suspected colonies were further evaluated using API 20E and API 20NE. No Gram(-) opportunistic pathogens were found during the entire observation. Baseline contamination level (>102 CFU mL -1 ) without use of disinfectants was significantly higher (P < 0AE0001) than at both first and second weeks when disinfectants were used. No colony was formed when Bio 2000 was used after both first and second weeks, whereas small number of CFU mL -1 was found at the end of the first week when Alpron (<10) was used. In conclusion, when used daily, both disinfectants prevent the development of bacterial contamination after first and second weeks with no significant differences (P = 0AE35).