Microbial assays for mutagenicity: A modified liquid culture method compared with the agar plate system for precision and sensitivity

Paratuberculosis is a chronic disease of ruminants caused by Mycobacterium avium subsp. Paratuberculosis (MAP). Since isolation of MAP type I (S) is rarely reported in Italy, our research was aimed at isolating, by an inexpensive liquid culture manual method, this type of MAP isolates. At first, we used an ELISA to point out to serologically positive samples from five flocks. Secondly, we used a fecal direct IS900-qPCR on the ELISA positive samples, in order to detect shedder animals. Feces from IS900-qPCR positive samples were inoculated in solid and liquid culture media. IS900-qPCR was further used to test the growth of MAP isolates in liquid medium, which were further confirmed by f57-qPCR and submitted to typing by specific PCR in order to identify the MAP type. Twenty-eight samples (24 fecal and four tissutal samples) were processed by culture methods, resulting in the isolation of six type I MAP field isolates. Notably, no isolates were recovered by solid media, underlining the utility of this liquid method. Few data about this type of MAP are currently available in Italy, and further analyses should be carried out in order to study the origin and epidemiology of type I strains circulating in Italy.

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Production of deoxynivalenol and related compounds in liquid culture by Fusarium graminearum

Canadian Journal of Microbiology ◽

10.1139/m83-179 ◽

1983 ◽

Vol 29 (9) ◽

pp. 1171-1178 ◽

Cited By ~ 82

Author(s):

J. D. Miller ◽

A. Taylor ◽

R. Greenhalgh

Keyword(s):

Fusarium Graminearum ◽

Fungal Biomass ◽

Organic Nitrogen ◽

Time Course ◽

Liquid Culture ◽

Culture Method ◽

Medium Ph ◽

Organic Nitrogen Source ◽

Major Factors ◽

Related Compounds

A liquid culture method for the production of deoxynivalenol and related compounds by Fusarium graminearum was developed. Major factors which stimulate the biosynthesis of these compounds include reduced oxygen levels, depletion of carbohydrate in the medium, pH, and possibly a low concentration of an organic nitrogen source. Isolates of F. graminearum were tested for the yields of four trichothecene mycotoxins and zearalenone in this system. The time course of acetyl deoxynivalenol, deoxynivalenol, and zearalenone in the fermentation was measured over a 21-day period against pH, glucose concentration, protein, fungal biomass, and ergosterol. A new ester of deoxynivalenol, 15-acetyl-deoxynivalenol, is reported from North American isolates of F. graminearum.

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Performance of Legiolert Test vs. ISO 11731 to Confirm Legionella pneumophila Contamination in Potable Water Samples

Pathogens ◽

10.3390/pathogens9090690 ◽

2020 ◽

Vol 9 (9) ◽

pp. 690 ◽

Cited By ~ 1

Author(s):

Maria Scaturro ◽

Matteo Buffoni ◽

Antonietta Girolamo ◽

Sandra Cristino ◽

Luna Girolamini ◽

...

Keyword(s):

Risk Assessment ◽

Legionella Pneumophila ◽

Water Samples ◽

Gold Standard ◽

Liquid Culture ◽

Potable Water ◽

Culture Method ◽

Alternative Methods ◽

Significant Difference

Detection and enumeration of Legionella in water samples is of great importance for risk assessment analysis. The plate culture method is the gold standard, but has received several well-known criticisms, which have induced researchers to develop alternative methods. The purpose of this study was to compare Legionella counts obtained by the analysis of potable water samples through the plate culture method and through the IDEXX liquid culture Legiolert method. Legionella plate culture, according to ISO 11731:1998, was performed using 1 L of water. Legiolert was performed using both the 10 mL and 100 mL Legiolert protocols. Overall, 123 potable water samples were analyzed. Thirty-seven (30%) of them, positive for L. pneumophila, serogroups 1 or 2–14 by plate culture, were used for comparison with the Legiolert results. The Legiolert 10 mL test detected 34 positive samples (27.6%) and the Legiolert 100 mL test detected 37 positive samples, 27.6% and 30% respectively, out of the total samples analyzed. No significant difference was found between either the Legiolert 10 mL and Legiolert 100 mL vs. the plate culture (p = 0.9 and p = 0.3, respectively) or between the Legiolert 10 mL and Legiolert 100 mL tests (p = 0.83). This study confirms the reliability of the IDEXX Legiolert test for Legionella pneumophila detection and enumeration, as already shown in similar studies. Like the plate culture method, the Legiolert assay is also suitable for obtaining isolates for typing purposes, relevant for epidemiological investigations.

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Mathematical Analysis of Growth and Interaction Dynamics of Streptomycetes and a Bacteriophage in Soil

Applied and Environmental Microbiology ◽

10.1128/aem.66.9.3868-3877.2000 ◽

2000 ◽

Vol 66 (9) ◽

pp. 3868-3877 ◽

Cited By ~ 22

Author(s):

N. J. Burroughs ◽

P. Marsh ◽

E. M. H. Wellington

Keyword(s):

Liquid Culture ◽

Burst Size ◽

Agar Plate ◽

Quantitative Agreement ◽

Host Population ◽

Soil Environment ◽

Host Interaction ◽

Primary Determinant ◽

Host Life ◽

Underlying Mechanisms

ABSTRACT We observed the infection cycle of the temperate actinophage KC301 in relation to the growth of its host Streptomyces lividansTK24 in sterile soil microcosms. Despite a large increase in phage population following germination of host spores, there was no observable impact on host population numbers as measured by direct plate counts. The only change in the host population following infection was the establishment of a small subpopulation of KC301 lysogens. The interaction of S. lividans and KC301 in soil was analyzed with a population-dynamic mathematical model to determine the underlying mechanisms of this low susceptibility to phage attack relative to aquatic environments. This analysis suggests that the soil environment is a highly significant component of the phage-host interaction, an idea consistent with earlier observations on the importance of the environment in determining host growth and phage-host dynamics. Our results demonstrate that the accepted phage-host interaction and host life cycle, as determined from agar plate studies and liquid culture, is sufficient for quantitative agreement with observations in soil, using soil-determined rates. There are four significant effects of the soil environment: (i) newly germinated spores are more susceptible to phage lysis than are hyphae of developed mycelia, (ii) substrate mycelia in mature colonies adsorb about 98% of the total phage protecting susceptible young hyphae from infection, (iii) the burst size of KC301 is large in soil (>150, 90% confidence) relative to that observed in liquid culture (120, standard error of the mean [SEM], 6), and (iv) there is no measurable impact on the host in terms of reduced growth by the phage. We hypothesize that spatial heterogeneity is the principal cause of these effects and is the primary determinant in bacterial escape of phage lysis in soil.

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Modified agar plate culture method for culture of Strongyloides stercoralis

Tropical Parasitology ◽

10.4103/2229-5070.162535 ◽

2015 ◽

Vol 5 (2) ◽

pp. 136 ◽

Cited By ~ 2

Author(s):

Vinay Khanna ◽

Kriti Tilak ◽

PeralamYegneswaran Prakash ◽

Chiranjay Mukhopadhyay

Keyword(s):

Agar Plate ◽

Culture Method ◽

Strongyloides Stercoralis

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A Versatile Liquid Culture Method to Control the <i>in Vitro</i> Development of Shoot and Root Apical Meristems of Bamboo Plants

American Journal of Plant Sciences ◽

10.4236/ajps.2020.112020 ◽

2020 ◽

Vol 11 (02) ◽

pp. 262-275

Author(s):

Most Tanziman Ara ◽

Taiji Nomura ◽

Yasuo Kato ◽

Shinjiro Ogita

Keyword(s):

Liquid Culture ◽

Culture Method ◽

Apical Meristems

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Novel culture method to diagnose fungal infections with biopsy tissues

10.1101/2020.01.22.916346 ◽

2020 ◽

Author(s):

Jiankang Zhao ◽

Yulin Zhang ◽

Yanyan Fan ◽

Zhujia Xiong ◽

Yudi Xia ◽

...

Keyword(s):

Culture System ◽

Liquid Culture ◽

Clinical Laboratory ◽

Fungal Infections ◽

Culture Method ◽

Culture Methods ◽

Promising Alternative ◽

Biopsy Tissue ◽

Liquid Culture System ◽

Potential Pathogen

AbstractBiopsy tissue is a difficult sample to gain for the identification of potential pathogen in the clinical laboratory. At present, there are no effective culture methods for small-sized biopsy tissue. In this study, we propose a novel tissue biopsy culture method based on Myco/F lytic liquid culture system, namely, tissue was grinded before injected into culture bottles. More types and numbers of fungi are cultivated using this culture system than sputum or BALF culture. A few of mycobacteria were also detected with ground tissues. The method may be a promising alternative to or supplement for the traditional plate culture in clinical practice.

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Enhancement of Campylobacter hepaticus culturing to facilitate downstream applications

Scientific Reports ◽

10.1038/s41598-021-00277-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Canh Phung ◽

Timothy B. Wilson ◽

José A. Quinteros ◽

Peter C. Scott ◽

Robert J. Moore ◽

...

Keyword(s):

Liquid Culture ◽

Vaccine Development ◽

Genomic Analysis ◽

Bacterial Biomass ◽

In Silico Analysis ◽

Culture Method ◽

Efficient Production ◽

Culture Density ◽

Brucella Broth

AbstractCampylobacter hepaticus causes Spotty Liver Disease (SLD) in chickens. C. hepaticus is fastidious and slow-growing, presenting difficulties when growing this bacterium for the preparation of bacterin vaccines and experimental disease challenge trials. This study applied genomic analysis and in vitro experiments to develop an enhanced C. hepaticus liquid culture method. In silico analysis of the anabolic pathways encoded by C. hepaticus revealed that the bacterium is unable to biosynthesise l-cysteine, l-lysine and l-arginine. It was found that l-cysteine added to Brucella broth, significantly enhanced the growth of C. hepaticus, but l-lysine or l-arginine addition did not enhance growth. Brucella broth supplemented with l-cysteine (0.4 mM), l-glutamine (4 mM), and sodium pyruvate (10 mM) gave high-density growth of C. hepaticus and resulted in an almost tenfold increase in culture density compared to the growth in Brucella broth alone (log10 = 9.3 vs 8.4 CFU/mL). The type of culture flask used also significantly affected C. hepaticus culture density. An SLD challenge trial demonstrated that C. hepaticus grown in the enhanced culture conditions retained full virulence. The enhanced liquid culture method developed in this study enables the efficient production of bacterial biomass and therefore facilitates further studies of SLD biology and vaccine development.

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

Journal of AOAC International ◽

10.5740/jaoacint.18-0245 ◽

2019 ◽

Vol 102 (4) ◽

pp. 1235-1240 ◽

Cited By ~ 2

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.

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