RAPID EVALUATION OF VIABLE CELL COUNTS BY USING THE MICROTITER SYSTEM AND MPN TECHNIQUE

1969 ◽  
Vol 32 (10) ◽  
pp. 408-409 ◽  
Author(s):  
Daniel Y. C. Fung ◽  
Allen A. Kraft
Keyword(s):  
Cell Concentration ◽  
Agar Plate ◽  
Viable Cell ◽  
Most Probable Number ◽  
Plate Method ◽  
Probable Number ◽  
Bacterial Cultures ◽  
Cell Counts ◽  
Time Space ◽  
Wide Range

A rapid procedure was developed for estimating viable cell counts in bacterial cultures by combining the Microtiter system and Most Probable Number technique. The correlation coefficient of the data between this method and the agar plate method was statistically significant at the 1% level. The advantage of this Microtiter-MPN procedure are savings of time, space, and material. Since the method covers a wide range of dilutions, estimates of cell concentration for proper dilutions are not needed in advance of enumeration procedures. Data are obtainable as early as 6 hr after samples are placed in incubation.

Comparison of Legiolert and a Conventional Culture Method for Detection of Legionella pneumophila from Cooling Towers in Québec

2019 ◽  
Vol 102 (4) ◽  
pp. 1235-1240 ◽  
Author(s):  
Isabelle Barrette
Keyword(s):  
Legionella Pneumophila ◽  
Cooling Tower ◽  
Test Procedure ◽  
Agar Plate ◽  
Culture Method ◽  
Most Probable Number ◽  
Cooling Towers ◽  
Plate Method ◽  
Probable Number ◽  
Compliance Testing

Abstract Background: Legionnaires’ disease is a potentially lethal pneumonia contracted through inhalation of aerosolized water contaminated with Legionella bacteria. Detection and control of L. pneumophila, the primary species responsible for the disease, is critical to public health. In Québec, cooling towers and evaporative condensers are required to follow a maintenance and testing program to ensure L. pneumophila concentrations remain at acceptable levels. Objective: This study compared a new culture method based on the most probable number approach, Legiolert®, with the formal culture method used at EnvironeX for regulatory compliance testing to quantify L. pneumophila from cooling tower waters in Québec. Methods: A split-sample analysis was performed in which 401 samples from cooling towers in Québec were tested with both methods. Results: Results with 74 positive samples showed that Legiolert provided a significant increase in sensitivity for L. pneumophila compared with the agar plate method. Cooling tower samples often contain non-Legionella flora that necessitate multiple treatment and plating conditions to prevent interference with the test. Legiolert showed little to no impact from non-Legionella organisms in this study. Conclusions: Overall, Legiolert showed several advantages over the agar plate method, including increased sensitivity, reduced interference, a simplified test procedure, and an easy-to-read positive signal.

Microbial Community Analysis inside a Biooxidation Heap for Gold Recovery in Equador

2017 ◽  
Vol 262 ◽  
pp. 135-138 ◽  
Author(s):  
Carlos L. Aspiazu ◽  
Paulina Aguirre ◽  
Sabrina Hedrich ◽  
Axel Schippers
Keyword(s):  
Microbial Community ◽  
Fine Fraction ◽  
Community Analysis ◽  
Gold Recovery ◽  
Microbial Community Analysis ◽  
Most Probable Number ◽  
Rrna Gene ◽  
Probable Number ◽  
Cell Numbers ◽  
Cell Counts

In a mine owned by the company Orenas S.A. (Equador), a biooxidation process for gold recovery has been developed. Refractory gold ore was crushed, milled and 500 ton of flotation concentrate was agglomerated by coating a support rock. This was piled up on a liner and the biooxidation process in the heap of 35x25x6 m3 was run for approximately 150 days. The oxidized material was subsequently removed for further processing. An outcrop allowed for depth dependent sampling of altogether 36 samples at three sites over the complete depth of 6 m. The fine fraction was removed from the host rock and sent to the laboratory for analysis of the microbial community. The pH ranged between 2.2 and 2.9. Total cell counts determined via counting under a fluorescence microscope after SYBR Green staining indicated a high microbial colonialization of the heap in all depths between 106 to 109 cells per g concentrate, however the highest cell numbers were mainly found in the upper 50 cm. Most-probable-number determination of living, acidophilic iron (II)-oxidizers for one site also revealed a decrease of cell numbers with depth (between 104 to 108 cells per g concentrate). Further molecular analyses of the community composition based on extracted DNA and 16S rRNA gene analyses by TRFLP and qPCR revealed a complex archaeal and bacterial community within the heap. It can be stated that an active community of acidophiles runs the biooxidation process in all sampled parts of the heap.

Colony-Forming Unit Enumeration by a Plate-MPN Method

1983 ◽  
Vol 46 (10) ◽  
pp. 836-841 ◽  
Author(s):  
S-T. TAN ◽  
R. B. MAXCY ◽  
W. W. STROUP
Keyword(s):  
Standard Technique ◽  
Most Probable Number ◽  
Plate Method ◽  
Probable Number ◽  
Microbial Counts ◽  
Colony Forming Unit ◽  
Pure Cultures ◽  
Petri Plate ◽  
Mpn Test ◽  
Surface Plate

Concepts of the standard surface plate method and the most probable number method (MPN) were combined to provide a new enumeration technique (plate-MPN). Three discrete 0.01-ml samples of an appropriate decimal dilution were inoculated onto each quadrant of a pre-dried petri plate. The discrete spots from the inoculum were then observed for growth after incubation. Results were interpreted analogous to a 3-tube MPN test using presently available tables. Application of the test to pure cultures and mixed flora provided no evidence to indicate the plate-MPN technique to be any less accurate than the standard technique for microbial counts. The plate-MPN technique was less precise than the standard technique. However, the plate-MPN technique has many advantages over traditional methods.

An Investigation of Escherichia coli O157 Contamination of Cattle during Slaughter at an Abattoir

2005 ◽  
Vol 68 (3) ◽  
pp. 451-457 ◽  
Author(s):  
NARELLE FEGAN ◽  
GLEN HIGGS ◽  
PAUL VANDERLINDE ◽  
PATRICIA DESMARCHELIER
Keyword(s):  
Escherichia Coli ◽  
Oral Cavity ◽  
Immunomagnetic Separation ◽  
Most Probable Number ◽  
Escherichia Coli O157 ◽  
Probable Number ◽  
Fecal Samples ◽  
E Coli ◽  
Cell Counts ◽  
Carcass Contamination

The extent of contamination with Escherichia coli O157 was determined for 100 cattle during slaughter. Samples from 25 consecutively slaughtered cattle from four unrelated groups were collected from the oral cavity, hide, rumen, feces after evisceration, and pre- and postchill carcass. Ten random fecal samples were collected from the pen where each group of animals was held at the abattoir. E. coli O157 was detected using automated immunomagnetic separation (AIMS), and cell counts were determined using a combination of most probable number (MPN) and AIMS. E. coli O157 was isolated from 87 (14%) of the 606 samples collected, including 24% of 99 oral cavity samples, 44% of 100 hides, 10% of 68 fecal samples collected postevisceration, 6% of 100 prechill carcass swabs, and 15% of 40 fecal samples collected from holding pens. E. coli O157 was not isolated from rumen or postchill carcass samples. E. coli O157 was isolated from at least one sample from each group of cattle tested, and the prevalence in different groups ranged from less than 1 to 41%. The numbers of E. coli O157 differed among the animals groups. The group which contained the highest fecal (7.5 × 105 MPN/g) and hide (22 MPN/cm2) counts in any individual animal was the only group in which E. coli O157 was isolated from carcasses, suggesting a link between the numbers of E. coli O157 present and the risk of carcass contamination. Processing practices at this abattoir were adequate for minimizing contamination of carcasses, even when animals were heavily contaminated with E. coli O157.

Microtiter Technique for Enumeration of Mesophiles, Psychrotrophs, and Coliforms in Raw and Pasteurized Milk

1977 ◽  
Vol 40 (11) ◽  
pp. 795-797 ◽  
Author(s):  
IVÀN A. CASAS ◽  
NELSON LEÓN ◽  
PEDRO IZQUIERDO
Keyword(s):  
Viable Cell ◽  
Limiting Factors ◽  
Plate Count ◽  
Microbial Quality ◽  
Pasteurized Milk ◽  
Standard Plate Count ◽  
Cell Counts ◽  
Count Method ◽  
Time Space ◽  
Standard Plate

The Microtiter Count Method was compared with the Standard Plate Count (SPC) method in evaluating mesophile, psychrotroph, and coliform counts for raw and pasteurized milk samples. Statistical analysis showed that the Microtiter Count Method was reliable when compared with the SPC for making viable cell counts on these products. The Microtiter Count Method is advantageous because it saves time, space, and material; this method should be useful for developing countries where availability of testing materials, manpower, and costs are limiting factors in surveillance of microbial quality.

scholarly journals Liquid preservation of human neutrophils stored in synthetic media at 22 degrees C: controlled observations on storage variables

Blood ◽  
1985 ◽  
Vol 66 (2) ◽  
pp. 267-272 ◽  
Author(s):  
L Glasser ◽  
RL Fiederlein ◽  
DW Huestis
Keyword(s):  
Glucose Utilization ◽  
Cell Function ◽  
Cell Concentration ◽  
Basal Medium ◽  
Human Neutrophils ◽  
Autologous Plasma ◽  
Bacterial Killing ◽  
Cell Counts ◽  
Wide Range ◽  
Synthetic Media

Abstract The purpose of this study was to use a chemically defined medium to identify essential substances and optimal conditions for the liquid storage of neutrophils at 22 degrees C. Several commercially available synthetic media were evaluated: L-15, McCoy's 5a, M199, minimum essential medium, Dulbecco's MEM, NCTC135, and RPMI 1640. Proteins, glucose, pH, and neutrophil concentration were systematically studied. Neutrophils were harvested by centrifugal cell separators or phlebotomy, and their maintenance was evaluated by monitoring cell counts, dye exclusion, phagocytosis, bacterial killing, and chemotaxis. Neutrophils stored equally well in all synthetic media except L-15; however, chemotaxis was poorly maintained in synthetic media as compared with autologous plasma. RPMI 1640 was arbitrarily selected as a basal medium to evaluate storage variables. RPMI 1640 supplemented with albumin to a concentration of 1% improved chemotaxis and was equivalent to plasma as a storage medium with regard to the in vitro functions tested. Cohn fractions IV-1, IV-4, and gamma globulin were not effective substitutes for albumin. Glucose is essential for neutrophil storage; its absence from the medium correlated with poor cell function. Optimal glucose requirements depend on the cell concentration. High glucose concentrations were toxic to neutrophils; at 1,000 mg/dL, chemotaxis was depressed by 58%. Glucose utilization was dependent on the initial pH of the medium and on the cell concentration. A wide range of hydrogen ion concentrations was tolerated, and the optimum pH range was 7.2 to 7.8. Cell concentration is an important variable because it affects the pH of the medium as well as glucose utilization.

scholarly journals Approaches for Eliminating Bacteria Introduced during In Situ Bioleaching of Fractured Sulfidic Ores in Deep Subsurface

2017 ◽  
Vol 262 ◽  
pp. 70-74 ◽  
Author(s):  
Hendrik Ballerstedt ◽  
Eva Pakostova ◽  
D. Barrie Johnson ◽  
Axel Schippers
Keyword(s):  
Ferric Iron ◽  
Iron Oxidation ◽  
Most Probable Number ◽  
Reduced Sulfur Compounds ◽  
Oxidation Activity ◽  
Probable Number ◽  
Horizon 2020 ◽  
Cell Counts ◽  
Microbial Iron Oxidation

The major objective of the EU Horizon 2020 project “BioMOre” is the technical realization of indirect in situ leaching of Kupferschiefer sandstone and black shale ore by a ferric iron lixiviant generated by a mixed culture of autotrophic, acidophilic, iron-oxidizing bacteria and archaea in a ferric iron-generating bioreactor (FIGB). These organisms could colonize the deeply buried geological formations even under anaerobic conditions as most are able to grow by coupling the reduction of ferric iron to the oxidation of reduced sulfur compounds in the absence of oxygen. Development of an inhibition protocol to eliminate these allochthonous microbial bioreactor populations subsequent to the completion of in situ bioleaching was therefore investigated. Column bioleaching experiments using a laboratory-scale FIGB confirmed not only that metals were solubilised from both the sandstone and shale ores, but also that significant numbers of bacteria were released from the FIGB. The efficacy of 13 different chemical compounds in inhibiting microbial iron oxidation has been tested at different concentrations in shake flask and FIGB-coupled columns. Iron-oxidation activity, microcalorimetrically-determined activity and ATP measurements, in combination with microscopic cell counts and biomolecular analysis (T-RFLP, qPCR), plate counts and most-probable-number (MPN), were used to monitor the inhibiting effects on the acidophiles. Complete inhibition of metabolic activity of iron-oxidizing acidophiles was achieved in the presence of 0.4 mM formate, 300 mM chloride, 100 mM nitrate, 10 mM of primary C6 to C8 alcohols, 100 mM 1-butanol, 100 mM 1-pentanol, 0.1 mM SDS or 0.35 mM benzoic acid. No inhibition was found for 0.6 mM acetic acid and 200 mM methanol. Based on these results a recipe for the chemical composition of the “decommissioning solution” is proposed.

scholarly journals Bacteria and protozoa populations in groundwater in landfill area in São Carlos, SP

1999 ◽  
Vol 30 (3) ◽  
pp. 196-202 ◽  
Author(s):  
Roberta Fusconi ◽  
Mirna Januária Leal Godinho
Keyword(s):  
Heterotrophic Bacteria ◽  
Mean Value ◽  
Microbial Populations ◽  
Most Probable Number ◽  
Plate Method ◽  
Probable Number ◽  
Mean Values ◽  
The Mean ◽  
The Town ◽  
Microaerophilic Conditions

The microbial populations of groundwaters were analyzed in a region under the influence of a landfill (piezometer L12) in the town of São Carlos, São Paulo, Brazil, and in an area not influenced by the landfill (piezometer L5). Heterotrophic bacteria were counted by spread plate method and the number of protozoa was estimated by the most probable number method. There was a larger number of organisms in well L12, with a mean value of 15.76 x 104 CFU/ml for bacteria and 9.7 MPN/ml for protozoa, whereas the mean values for piezometer L5 were 2.88 x 104 CFU/ml for bacteria and 3.4 MPN/ml for protozoa. The greater abundance detected in piezometer L12 may be related to the influence of the leachate through the landfill on the microbial populations, also demonstrated by deoxygenation and by the high conductivity values (3530 µS/cm) compared to piezometer L5 (2.47 mg/L dissolved oxygen and 42 µS/cm conductivity). The most commonly detected protozoa were amoebae and flagellates. The density of flagellate protozoa determined under microaerophilic conditions was 10 times higher than that determined under aerobic conditions.

Evaluation of Two Standard and Two Chromogenic Selective Media for Optimal Growth and Enumeration of Isolates of 16 Unique Bacillus Species

2017 ◽  
Vol 80 (6) ◽  
pp. 952-962 ◽  
Author(s):  
M. Shahjahan Kabir ◽  
Ying-Hsin Hsieh ◽  
Steven Simpson ◽  
Khalil Kerdahi ◽  
Irshad M. Sulaiman
Keyword(s):  
Food Poisoning ◽  
Optimal Growth ◽  
Egg Yolk ◽  
Growth Conditions ◽  
Bromothymol Blue ◽  
Culture Collection ◽  
Most Probable Number ◽  
Bacillus Species ◽  
Probable Number ◽  
Wide Range

ABSTRACTThe genus Bacillus is a group of gram-positive endospore-forming bacteria that can cause food poisoning and diarrheal illness in humans. A wide range of food products have been linked to foodborne outbreaks associated with these opportunistic pathogens. The U.S. Food and Drug Administration recommends (in their Bacteriological Analytical Manual) the use of Bacara or mannitol egg yolk polymyxin (MYP) agar plates and the most-probable-number (MPN) method for enumeration and confirmation of Bacillus cereus and related species isolated from foods, sporadic cases, outbreaks, and routine environmental surveillance samples. We performed a comparative analysis of two chromogenic media (Bacara and Brilliance) and two traditional media (MYP and polymyxin egg yolk mannitol bromothymol blue agar [PEMBA]) for the isolation and enumeration of 16 Bacillus species under modified growth conditions that included pH, temperature, and dilution factor. A total of 50 environmental, food, and American Type Culture Collection reference isolates from 16 distinct Bacillus species were evaluated. A food adulteration experiment also was carried out by artificially adulterating two baby food matrices with two isolates each of B. cereus and Bacillus thuringiensis. Our results clearly indicated that chromogenic plating media (Bacara and Brilliance) are better than conventional standard media (MYP and PEMBA) for the detection and enumeration of B. cereus in foods and other official regulatory samples. The comparison of the two chromogenic media also indicated that Brilliance medium to be more efficient and selective for the isolation of Bacillus.

Uptake and Elimination of Bacteria in Shellfish*

1980 ◽  
Vol 43 (2) ◽  
pp. 124-126 ◽  
Author(s):  
FRANK O. PERKINS ◽  
DEXTER S. HAVEN ◽  
REINALDO MORALES-ALAMO ◽  
MARTHA W. RHODES
Keyword(s):  
Crassostrea Virginica ◽  
Environmental Conditions ◽  
Fecal Coliform ◽  
Sea Water ◽  
Fecal Coliforms ◽  
Most Probable Number ◽  
Probable Number ◽  
General Review ◽  
Wide Range ◽  
Bacterial Accumulation

A general review of knowledge concerning bacterial accumulation and depletion by commercially significant bivalve molluses is presented. Naturally contaminated shellfish can eliminate fecal coliforms (FC) in 48 h to levels below most market standards over a wide range of environmental conditions when sea water flowing to the molluses is treated so that fecal coliform levels are indeterminate or marginally determinate as assayed by standard methodology. Most probable number (MPN) enumerations of shellfish depurated for 48 h by the authors yielded a median value of < 18 FC/100 g of oyster (Crassostrea Virginica) meats with < 10% of the samples exceeding 78 FC/100 g.

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