Legionella quantification in environmental samples is overestimated by qPCR. Combination with a viable dye, such as Propidium monoazide (PMA), could make qPCR (named then vPCR) very reliable. In this multicentre study 717 artificial water samples, spiked with fixed concentrations of Legionella and interfering bacterial flora, were analysed by qPCR, vPCR and culture and data were compared by statistical analysis. A heat-treatment at 55 °C for 10 minutes was also performed to obtain viable and not-viable bacteria. When data of vPCR were compared with those of culture and qPCR, statistical analysis showed significant differences (P < 0.001). However, although the heat-treatment caused an abatement of CFU/mL ≤1 to 1 log10 unit, the comparison between untreated and heat-treated samples analysed by vPCR highlighted non-significant differences (P > 0.05). Overall this study provided a good experimental reproducibility of vPCR but also highlighted limits of PMA in the discriminating capability of dead and live bacteria, making vPCR not completely reliable.
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http://dx.doi.org/10.1016/j.diagmicrobio.2016.04.009 | DOI Listing |
Biol Methods Protoc
November 2024
Faculty of Natural Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Bratislava, 84215, Slovakia.
Determining the number of viable cells by calculating colony-forming units is time-consuming. The evaluation of mixed biofilms consisting of different species is particularly problematic. Therefore, the aim of this study was to optimize a molecular method-propidium monoazide quantitative polymerase chain reaction (PMA-qPCR)-for accurate and consistent differentiation between living and dead cells.
View Article and Find Full Text PDFFront Cell Infect Microbiol
December 2024
Key Laboratory of Preclinical Study for New Drugs of Gansu Province, School of Basic Medical Sciences, Lanzhou, China.
The zoonotic pathogen is responsible for diverse human diseases, from mild to life-threatening, but it often eludes detection in culture-based assays. This study investigates the potential of to enter a viable but nonculturable (VBNC) state when exposed to human fever temperature or antibiotics, with this state confirmed by successful resuscitation. Viability was assessed using SYBR Green I/PI staining and propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR), while culturability was determined through colony-forming unit (CFU) counting on blood agar plates.
View Article and Find Full Text PDFAntibiotics (Basel)
October 2024
Department of Medicine, Faculty of Medicine, University Complutense, 28040 Madrid, Spain.
: The evaluation of the efficacy of antibacterial treatments in complex oral ecosystems is limited by the inability to differentiate live from dead bacteria using omic techniques. The objective of this study was therefore to assess the ability of the combination of the 16S rRNA Illumina sequencing methodology and the action of propidium monoazide (PMA) to study viable bacterial profiles in oral biofilms after exposure to an antiseptic compound. : Cariogenic supragingival biofilms were developed in an ex vivo model for 96 h, using saliva from healthy volunteers.
View Article and Find Full Text PDFHarmful Algae
November 2024
Department of Marine Environmental Engineering, Gyeongsang National University, 2 Tongyeonghaean-ro, Tongyeong, Gyeongnam 53064, Republic of Korea. Electronic address:
This study investigated the use of propidium monoazide (PMA) to improve the accuracy of environmental DNA (eDNA) monitoring by selectively detecting intracellular DNA (iDNA) from living cells, while excluding extracellular DNA (exDNA) from dead organisms. eDNA samples were collected from various depths off the coast of Tongyeong, South Korea, and analyzed alongside environmental factors, such as temperature, dissolved oxygen, turbidity, and nutrient levels. The results showed that PMA-treated iDNA provided a more accurate estimate of viable harmful algal bloom species (HABs) than total eDNA and DNase-treated iDNA.
View Article and Find Full Text PDFAnal Chem
November 2024
Research Centre for Analytical Instrumentation, Institute of Cyber-Systems and Control, State Key Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou, Zhejiang 310027, P. R. China.
O157:H7 ( O157:H7) is a prominent pathogenic bacterium that poses serious risks to food safety and public health. Rapid and accurate detection of live O157:H7 is of great importance in food quality monitoring and clinical diagnosis. Here, we report a propidium monoazide-assisted nonamplification digital CRISPR/Cas12a assay for sensitive and rapid detection of live O157:H7.
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