Comparative study of membrane filtration and enrichment media for the isolation and enumeration of Pseudomonas aeruginosa from sewage, surface water, and swimming pools

1985 ◽  
Vol 31 (8) ◽  
pp. 686-692 ◽  
Author(s):  
A. H. Havelaar ◽  
M. During ◽  
E. H. M. Delfgou-Van Asch

The recovery of Pseudomonas aeruginosa on several selective culture media was tested using raw sewage and secondary sewage effluent samples as well as spiked chlorinated imitation swimming water and samples from whirlpools. mPA-medium B gave good recovery of both vital and chlorine-injured P. aeruginosa and selectivity was greater than 90% when analysing whirlpool samples. It is therefore the medium recommended for examination of chlorinated swimming pools. When analysing sewage polluted water with the mPA-B medium, reduced selectivity was noted from low verification rates and from overgrowth by competitive flora. A modified medium (mPA-D; addition of cetrimide, omission of sulphapyridine and actidione) was more selective and sufficiently recovered noninjured cells. Chlorine-injured cells were completely inhibited, however. C-390 (9-chloro-9-(4-diethylaminophenyl)-10-phenylacridan) was confirmed to be highly selective for P. aeruginosa when used in spread plates at a concentration of 30 μg/mL; P. aeruginosa was slightly inhibited. However, the medium could not be used with conventional membrane filtration techniques, because cellulose ester filters interfered with the selective action of C-390. Selectivity could be improved by using Gelman Tuffryn (polysulphone) filters and increasing the C-390 concentration to 120 μg/mL. At this concentration, however, the medium was strongly inhibitory to P. aeruginosa; resuscitation only partially improved recovery. Two other membrane filtration media were tested. Both cetrimide – nalidixic acid agar and Drake's medium No. 19 were inhibitory to chlorine-injured cells. Several types of membrane filters were tested and there was little difference between them. In the most-probable-number technique, recovery of P. aeruginosa was shown to be excellent when using asparagine broth. Malachite green broth was strongly inhibitory to chlorine-injured P. aeruginosa.

2014 ◽  
Vol 13 (2) ◽  
pp. 427-436 ◽  
Author(s):  
David P. Sartory ◽  
Danièle Pauly ◽  
Nathalie Garrec ◽  
Lucia Bonadonna ◽  
Maurizio Semproni ◽  
...  

In this study, the performance of a new most probable number (MPN) test (Pseudalert®/Quanti-Tray®) for the enumeration of Pseudomonas aeruginosa from hospital waters was compared with both international and national membrane filtration-based culture methods for P. aeruginosa: ISO 16266:2006 and UK The Microbiology of Drinking Water – Part 8 (MoDW Part 8), which both use Pseudomonas CN agar. The comparison based on the calculation of mean relative differences between the two methods was conducted according to ISO 17994:2014. Using both routine hospital water samples (80 from six laboratories) and artificially contaminated samples (192 from five laboratories), paired counts from each sample and the enumeration method were analysed. For routine samples, there were insufficient data for a conclusive assessment, but the data do indicate at least equivalent performance of Pseudalert®/Quanti-Tray®. For the artificially contaminated samples, the data revealed higher counts of P. aeruginosa being recorded by Pseudalert®/Quanti-Tray®. The Pseudalert®/Quanti-Tray® method does not require confirmation testing for atypical strains of P. aeruginosa, saving up to 6 days of additional analysis, and has the added advantage of providing confirmed counts within 24–28 hours incubation compared to 40–48 hours or longer for the ISO 16266 and MoDW Part 8 methods.


1993 ◽  
Vol 27 (3-4) ◽  
pp. 207-210 ◽  
Author(s):  
Gary A. Toranzos ◽  
Abdiel J. Alvarez ◽  
Elizabeth A. Dvorsky

Enteric pathogens may be present in fecally contaminated waters at extremely low concentrations. In addition, these pathogens may be injured when exposed to the environment and may not be able to grow in laboratory culture media or such media may simply not exist for their progagation in the laboratory. It is paramount thus to use techniques which do not depend on culture techniques for the detection of these pathogens and that allow for the detection of single-cell concentrations. The polymerase chain reaction (PCR) technique has been shown to be an excellent and sensitive means of detecting pathogens in waters. Membrane filtration has been combined with PCR and DNA hybridization techniques to be able to detect the DNA equivalent of one single cell in large volumes of water. In addition, this combination of methods allows for the amplification of different target genes fiat may be present in the sample, since the membrane can be subjected to repeated amplification reactions under different conditions. A Most Probable Number PGR was developed which allows for the quantification of gene copy number and thus permits extrapolation to estimate the number of bacterial cells in the original sample.


1991 ◽  
Vol 24 (2) ◽  
pp. 143-147 ◽  
Author(s):  
N. A. Grabow ◽  
R. Kfir ◽  
W. O. K. Grabow

A new quantitative method for the enumeration of Legionella bacteria in water is described. Appropriate tenfold serial dilutions of water samples concentrated by membrane filtration are plated in triplicate on buffered charcoal yeast extract agar. After incubation for 3 days representative smears from individual plates are tested for the presence of Legionella by direct fluorescent antibody staining. The number of positive plates in each dilution is used to calculate the Legionella count by means of conventional most probable number statistics. In comparative tests on a variety of water samples this method yielded significantly higher counts than previously used procedures.


1983 ◽  
Vol 29 (10) ◽  
pp. 1261-1269 ◽  
Author(s):  
W. J. Robertson ◽  
R. S. Tobin

Fifteen stations, in two estuaries, along the Northumberland Strait of Nova Scotia were examined between June and September 1981 for a relationship between the concentrations of commonly monitored fecal indicator bacteria and the potential pathogens Candida albicans, Pseudomonas aeruginosa, and Vibrio parahaemolyticus. Increased densities of these three organisms were usually associated with high densities of indicator bacteria. Whereas C. albicans and P. aeruginosa occur in human fecal wastes, V. parahaemolyticus is indigenous to the marine environment and positively responds to elevated nutrient levels in sewage. There is also some evidence that these bacteria survive as long or longer in marine waters than the common indicator bacteria. While membrane-filtration techniques for the enumeration of C. albicans and P. aeruginosa proved satisfactory, a V. parahaemolyticus membrane-filtration method lacked specificity and was supplemented by a most-probable-number method. In marine recreational and shellfish waters, these three organisms could complement fecal coliforms and fecal streptococci as indicators of human fecal contamination.


2015 ◽  
Vol 5 (2) ◽  
pp. 48-54
Author(s):  
Mathews P. Raj ◽  
Anitha A. Abraham ◽  
Jayarama Reddy

  Lake ecosystems are degraded with the increase in urbanization and anthro-pogenic activities. A study was taken up to analyze the effects of water quality of Ibalur Lake, Bangalore, India. The physico- chemical parameters and bacteriological examination of lake water was done for a period of 3 months from December 2013 – February 2014. The values recorded for Dissolved oxygen (DO), Biological oxygen demand (BOD) and Chemical oxygen demand (COD) were found to be zero. The average values recorded for parameters like calcium, total alkalinity, hardness were 231mg/L, 197mg/L and 587.1 mg/L respectively which were found exceeding the WHO standards set for drinking water; Parameters like Magnesium, Sodium, Chlorides, Sulphates had an average value of 140, 18.4, 59.5, 15 expressed in mg/L, which were within the WHO standards. Coliform count customized using the standard Most Probable Number (MPN) test reported a very high bacterial activity and proved the lake water is non-potable. Analysis carried out to determine the effects of pollutants on the vertebrate system (zebra fish) showed that the polluted waters of the lake have deleterious effects on zebra fish. With these observations it can be concluded that the pollutants of the lake can have detrimental impact on the biotic components.


2020 ◽  
Vol 42 ◽  
pp. e52965
Author(s):  
Wender Cardoso Silva ◽  
Ilva de Fátima Souza ◽  
Vivian Machado Benassi ◽  
Juan Pedro Bretas Roa ◽  
Paulo Henrique Graziotti ◽  
...  

The present work aimed to evaluate the degradability of the chitosan polymer by soil microorganisms. This evaluation was accomplished using the Most Probable Number (MPN) method by plating in drops so that soil microorganisms capable of degrading the polymeric material could be quantified. Soil samples diluted in three specific culture media for each type of microorganism were plated – bacteria, fungi and actinobacteria – and they were maintained at 28°C for seven days to determine the growth rate of fungi and actinobacteria, and for 48 hours for the development of bacteria. Significant differences in the MPN of actinobacteria relative to the other groups analyzed were observed. Thus, the method used was effective for determining the degradability of the chitosan biopolymer when observing the development of microorganisms subjected to the replacement of the carbon source by the addition of 2% w v-1 of the chitosan biopolymer to the culture medium. The formation of clear regions around the microbial colonies was a strong indicator of biodegradation.


1982 ◽  
Vol 89 (1) ◽  
pp. 149-154 ◽  
Author(s):  
J. L. Smith ◽  
S. Rockliff

SUMMARYA single-tube confirmatory test that allows a result to be obtained in 4 h has been developed from the single-tube confirmatory test recommended by the Joint Committee of the Public Health Laboratory Service and the Standing Committee of Analysts (PHLS/SCA, 1980). A variety of river, lake and reservoir samples were examined for the presence ofE. coliusing either most probable number (MPN) or membrane filtration (MF) technique, and the PHLS/SCA recommended confirmatory medium (LTMB) was evaluated against traditional methods. To improve the performance of LTMB, the medium was modified and this modified medium when used in 0·1 ml volumes and incubated for 4 h at 44°C provided 99% agreement with traditional methods.


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