Most Probable Number

All the physical and biological parameters were determined. The temperature of water sample in studied area was between 26.4-28.5, lower than World Health Organisation (WHO) prescribed limit. The pH of the water samples in Northeast Bangalore is in range of 6.5-8.5, which was in accordance to WHO, Bureau for Indian Standard (BIS) and Central Pollution Control Board (CPCB). TDS values in water samples range from 200-820 mg/L. Nine samples showed higher TDS values and TSS values range from 20-400 mg/L. The samples S01, S04, S08, S14, S15, S19, and S20 contain high MPN Index above 50 and S02, S03, S05, S06, S07, S09, S10, S11, S12, S13, S16, S17, and S18 contain low MPN index below 50. BOD and COD values range from 1.2-5.2 mg/l and 8.8-42.1 mg/l respectively. All twenty samples showed higher DO values than the prescribed limit by WHO. But according to BIS and CPCB, S02, S05, were low than their required limit. S11, S15 and S17 were just at 6.0, rest were higher than their required limit. Seven bacterial strains were isolated from the twenty water samples i.e. Escherichia spp., Klebsiella spp., Shigella spp., Yersinia spp. Enterobacter spp., Vibrio spp., and Salmonella spp. The purification and disinfection is to control the bacterial contamination. Water samples from Northeast Bangalore investigated that moderately contaminated. The presence of bacteria in the water is the indication of poor quality of water. According to WHO, BIS and CPCB standards, the water can be used as drinking water with caution.

Increasing human population coupled with their daily activities has continued to impact on the quality of surface and underground water bodies. Hence, the need to assess the portability of some major sources of drinking water. In the study, the two major sources of drinking water (Hand dug wells and boreholes) within Amai Kingdom, one of the major growing communities in Ukwuani Local Government Area of Delta State, and currently hosting Novena University Campus, where analysed microbiologically to ascertain their portability. A total of 60 water samples were collected from the available boreholes and hand dug well sited within the five major quarters in Amai town, namely Umuekum, Umubu, Amai-Nge, Ishikaguma and Umuosele, and analysed for total heterotrophic microbial (bacterial and fungal) counts, coliforms and faecal coliforms using standard plate count and most probable number (MPN) techniques. The results where compared with WHO standard for drinking water sources. The mean total heterotrophic bacterial counts (THBC) were found to range from 8.0 x 10 1 – 6.4 x 10 3 cfu/ml for borehole water samples and 1.9 x 10 2 – 2.5 x 10 4 cfu/ml for well water samples. The total heterotrophic fungal counts (THFC) ranged from 0-2.0 x 10 2 cfu/ml and 0 – 6.0 x 10 2 cfu/ml respectively. Statistical analysis revealed that the THBCs were significantly higher (p<0.05) in well waters than in borehole water samples. Coliforms were present in all the water samples examined up to levels of 9-26 MPN/100ml, while a few borehole and entire well waters samples demonstrated positive results to faecal coliform test. The dominant bacterial genera encountered were sp. and Pseudomonas sp., while the fungal isolates were Penicillium sp. and Rhizopus sp. Comparing the findings with zero coliform count per 100 ml of water samples according to WHO standard for portable water, suggest that the microbial qualities of drinking waters from some borehole and majority of hand dug wells in Amai Kingdom are poor and possess threat to public health. Hence, simple water treatment method such as boiling, regular disinfection and cleaning of borehole storage vessels or tanks as well as general public education on proper disposal of sewage are recommended in the study area.

This study investigates the extra UV fluence needed to meet the International Maritime Organisation's ballast water discharge standards for the 10–50 μm size-class using the approved vital stain (VS) method compared to the Most Probable Number (MPN) method for organism viability assessment. Low-and medium pressure UV collimated beam treatments were applied to natural algae collected in temperate and tropical water environments and analysed using both methods. About 10 times higher UV fluence was required to meet discharge standards when using VS compared to MPN. Implementing a dark-hold period after UV treatments decreased algal viability. Length of dark-hold period to meet discharge standards decreased with increasing UV fluence. No significant differences between temperate and tropical samples were observed. The results showed that UV treated algae assessed using the VS method could meet discharge standards by increasing fluence and/or introducing a dark-hold period.

This study aimed to determine the occurrence of Vibrio parahaemolyticus in cockles (Anadara granosa) at a harvesting area and to detect the presence of virulent strains carrying the thermostable direct hemolysin (tdh) and TDH-related hemolysin genes (trh) using PCR. Of 100 samples, 62 were positive for the presence of V. parahaemolyticus with an MPN (most probable number) value greater than 3.0 (>1100 MPN per g). The PCR analysis revealed 2 samples to be positive for the tdh gene and 11 to be positive for the trh gene. Hence, these results demonstrate the presence of pathogenic V. parahaemolyticus in cockles harvested in the study area and reveal the potential risk of illness associated with their consumption.

This paper describes a Bayesian technique for unsupervised classification of data and its computer implementation, AutoClass. Given real valued or discrete data, AutoClass determines the most probable number of classes present in the data, the most probable descriptions of those ...

Temporal variations in the diatom benthic propagule (DBP) community and its role in the phytoplankton community in a monsoon-affected tropical estuary, Zuari estuary, Goa (India) is presented. The DBP from the sediments was enumerated using an extinction dilution method (Most Probable Number method), which allows estimation of resting stages through examination of germinated vegetative cells in culture. The DBP community was dominated by planktonic species belonging to the genera Skeletonema, Fragilariopsis, Thalassiosira and Chaetoceros. Benthic propagules (BP) of S. costatum and Fragilariopsis sp. were dominant throughout the year. Between these two species, only S. costatum showed a linear relationship between the BP and planktonic cells indicating that this species is particularly important in coupling of pelagic and benthic ecosystems. During the onset and restart of monsoon after an intermittent break, water column was stratified, with a low salinity layer arising from riverin...

A nested-PCR temporal temperature gradient gel electrophoresis (TTGE) approach was developed for the detection of bacteria belonging to phylogenetic cluster I of the genus Clostridium (the largest clostridial group, which represents 25% of the currently cultured clostridial species) in cheese suspected of late blowing. Primers were designed based on the 16S rRNA gene sequence, and the specificity was confirmed in PCRs performed with DNAs from cluster I and non-cluster I species as the templates. TTGE profiles of the PCR products, comprising the V5-V6 region of the 16S rRNA gene, allowed us to distinguish the majority of cluster I species. PCR-TTGE was applied to analyze commercial cheeses with defects. All cheeses gave a signal after nested PCR, and on the basis of band comigration with TTGE profiles of reference strains, all the bands could be assigned to a clostridial species. The direct identification of Clostridium spp. was confirmed by sequencing of excised bands. C. tyrobutyri...

Microbiological analyses of fresh fruits and vegetables produced by organic and conventional farmers in Minnesota were conducted to determine the coliform count and the prevalence of Escherichia coli, Salmonella, and E. coli O157:H7. A total of 476 and 129 produce samples were collected from 32 organic and 8 conventional farms, respectively. The samples included tomatoes, leafy greens, lettuce, green peppers, cabbage, cucumbers, broccoli, strawberries, apples, and seven other types of produce. The numbers of fruits and vegetables was influenced by their availability at participating farms and varied from 11 strawberry samples to 108 tomato samples. Among the organic farms, eight were certified by accredited agencies and the rest reported the use of organic practices. All organic farms used aged or composted animal manure as fertilizer. The average coliform counts in both organic and conventional produce were 2.9 log most probable number per g. The percentages of E. coli-positive sam...

Phenanthrene-metabolizing soil microbial communities were characterized by examining mineralization of [14C]phenanthrene, by most-probable-number (MPN) counting, by 16S-23S spacer DNA analysis of the numerically dominant, culturable phenanthrene-degrading isolates, and by examining incorporation of [13C]phenanthrene-derived carbon into sterols and polar lipid fatty acids (PLFAs). An unpolluted agricultural soil, a roadside soil diffusely polluted with polycyclic aromatic hydrocarbons (PAHs), and two highly PAH-polluted soils from industrial sites were analyzed. Microbial phenanthrene degraders were not detected by MPN counting in the agricultural soil and the roadside soil. In the industrial soils, phenanthrene degraders constituted 0.04 and 3.6% of the total number of CFU. 16S-23S spacer DNA analysis followed by partial 16S DNA sequencing of representative isolates from one of the industrial soils showed that one-half of the isolates belonged to the genus Sphingomonas and the other...

Biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated sediment is an attractive remediation technique and its success depends on biodegradation kinetics, and the optimal condition for the PAH-degrading isolates; however, information on this aspect is still scarce. The effects of multi-factors on biodegradation of phenanthrene, a 3-ring model PAH, in contaminated sediment slurry by Sphingomonas sp. a bacterial strain isolated from surface mangrove sediment, were investigated using the orthogonal experimental design (form L16(45)). The most significant factors were salinity and inoculum size, while the effects of phenanthrene concentrations, nutrient addition and temperatures were insignificant. The optimal biodegradation condition in contaminated mangrove sediment slurry was 30 °C, 15 ppt salinity, a carbon/nitrogen ratio of 100:1 (the background ratio in sediment) and an inoculum size of 106 most probable number g−1 sediment. The phenanthrene biodegradation could be best described by the first order rate model, C = C0e−kt, where k (the rate constant) is equaled to 0.1185, under the optimal condition. The kinetic model was verified and its validity in predicting biodegradation by Sphingomonas sp. at various phenanthrene concentrations was proved by experimental data.

Spices can present high microbial counts and Clostridium perfringens, Bacillus cereus, Salmonella and Shigella, among others have been isolated from spices. C. perfringens is an important pathogen agent causing, among other diseases, enteritis in humans caused by C. perfringens ...

Three clinical isolates of Acanthamoeba (A. castellanii, A. polyphaga, and A. mauritaniensis) were used to evaluate the cysticidal activity of four different contact lens multi-purpose solutions (Complete Protec, ReNu MultiPlus, Solocare Aqua, and Opti-free Aldox). Enumeration of amoebic was carried out with the control and test samples at 0, 2, 4, 6, 8, 10, and 24 hours after being added to the solutions using the most probable number (MPN) technique. A contact lens solution which achieved a 3-log reduction of Acanthamoeba during the manufacturer&#39;s minimum recommended disinfection time (MMRDT) was considered an effective solution. The studied contact lens solutions demonstrated decreasing number of amoebic with increasing exposure times, but were not effective against Acanthamoeba cysts during the MMRDT. Solocare Aqua gave the greatest reduction in A. castellanii (0.70-log reduction) and A. mauritaniensis (0.33-log reduction) by 4 hours. Only Solocare Aqua caused a 3-log reduct...

The present study was undertaken to examine the drinking water quality of Rawal Treatment Plant, Rawalpindi and its distribution network by collecting samples from eight different locations. The aim was to determine potential relationship between the presence of microorganisms and chlorine residual in the distribution network. Quantification of chlorine residual, turbidity, standard plate count (SPC), fecal and total coliforms by Most Probable Number (MPN) was performed. Three different forms of chlorine were measured at each sampling station such as free chlorine, residual chlorine, chloramines and total chlorine residual. A critical evaluation of data presented indicated that pH generally ranged from 7.02–7.30; turbidity varied from 0.34–2.79 NTU; conductivity fluctuated from 359–374 μS/cm; and TDS values were found to be ranging between 180–187 mg/l. Station # 7 was found to be most contaminated. The value of total chlorine was found to be 0.86 to1.7 mg/l at Station # 3 and 6, re...

New Zealand&#39;s freshwater ecosystems are subject to microbial contamination from a predominantly agricultural landscape. This study examines the spatial and temporal distribution of the human pathogen Campylobacter in the lower Taieri River, South Island (New Zealand). Enumeration of thermophilic Campylobacter from river samples was performed using a most probable number (MPN) method. Seasonal variation in Campylobacter levels was evident, with higher median levels detected in summer, when human exposure through recreational water use is maximal. Campylobacter levels varied significantly among the 10 sampling sites, increasing below a major tributary entering the river and then showing a downstream decrease. These changes probably resulted from inputs from adjacent farms and instream Campylobacter losses (settling, death). Two main peaks in the flux of Campylobacter were observed, one in winter and one in summer. A decrease in notified cases of campylobacteriosis in the human pop...

Ice cream produced by three large-scale and three small-scale manufacturers were studied to determine the microbial load or colony forming units per gram (cfu/g) using the standard aerobic plate count. Analyses for the most probable number/gram (MPN/g) of total coliforms and fecal coliforms, presence of coagulase positive Staphylococcus and Salmonella were also done in order to determine if the samples

A bench-scale horizontal-flow anaerobic immobilized biomass (HAIB) reactor was assayed aiming to verify its performance in degrading benzene, toluene, ethylbenzene and xylene (BTEX). A 138 ml HAIB reactor filled with polyurethane foam matrices containing immobilized anaerobic biomass was initially fed with synthetic substrate containing protein, carbohydrates and lipids. Thereafter, BTEX degradation was evaluated in the presence of the co-solvents ethanol and lineal alkylbenzene sulphonate (LAS), in two sequential experiments. The inlet BTEX concentration ranged from 1.3 to 27.0 mg/L of each compound and outlet concentrations were lower than 0.1 mg BTEX/L for both the experiments with ethanol and LAS. An active enriched microbial consortium was observed in the reactor, containing BTEX-degraders, and also acetogenic, acetotrophic and hydrogenotrophic microorganisms. The results from the most probable number (MPN) tests indicated a decrease in the number of methanogenic archae, while ...

Population development of key groups of bacteria involved in municipal refuse conversion to methane was measured from the time of initial incubation through the onset of methane production. Hemicellulolytic bacteria, cellulolytic bacteria, hydrogen-producing acetogens, and acetate- and H(2)-plus-CO(2)-utilizing methanogens were enumerated by the most-probable-number technique with media containing oat spelt xylan, ball-milled cellulose, butyrate, acetate, and H(2) plus CO(2), respectively. Refuse decomposition was monitored in multiple replicate laboratory-scale sanitary landfills. A laboratory-scale landfill was dismantled weekly for microbial and chemical analysis. Leachate was neutralized and recycled to ensure methanogenesis. The methane concentration of the sampled containers increased to 64% by day 69, at which time the maximum methane production rate, 929 liters of CH(4) per dry kg-year, was measured. Population increases of 2, 4, 5, 5, and 6 orders of magnitude were measured...

Wastewater from tanneries contains high concentrations of organic matter, chromium, nitrogen, and sulfur compounds. In this study, an artificial wetland is is used as the tertiary treatment in a tannery in León Gto., México. It consists of three subplots with an area of about 450 ...