scholarly journals A real-time PCR for the differentiation of typhoidal and non-typhoidal Salmonella

2019 ◽  
Author(s):  
Satheesh Nair ◽  
Vineet Patel ◽  
Tadgh Hickey ◽  
Clare Maguire ◽  
David R Greig ◽  
...  
Keyword(s):  
Public Health ◽  
Real Time ◽  
Real Time Pcr ◽  
Genomic Analysis ◽  
Rapid Identification ◽  
Specific Gene ◽  
Whole Genome ◽  
Pcr Assay ◽  
Gene Encoding ◽  
Accurate Identification

AbstractRapid and accurate differentiation of Salmonella spp. causing enteric fever from non-typhoidal Salmonella is essential for clinical management of cases, laboratory risk management and implementation of public health measures. Current methods used for confirmation of identification including biochemistry and serotyping as well as whole genome sequencing analyses, takes several days. Here we report the development and evaluation of a real-time PCR assay that can be performed directly on crude DNA extracts from bacterial colonies, for the rapid identification of typhoidal and non-typhoidal Salmonella.This novel two-hour assay identifies the genus Salmonella by detecting the ttr gene, encoding tetrathionate reductase, and defines typhoidal Salmonella by the detection of S. Typhi and Paratyphi-specific gene combinations. PCR assay performance was determined using 211 clinical cultures of Salmonella (114 non-typhoidal and 97 Typhoidal strains) and 7 clinical non-Salmonella cultures. In addition, the specificity of the assay was evaluated in silico using a diverse in-house collection of 1882 Salmonella whole genome sequences. The real-time PCR results for 218 isolates and the genomic analysis of the 1882 isolates produced 100% sensitivity and 100% specificity (based on a 7 gene profile) for identifying typhoidal Salmonella compared to the Salmonella whole genome sequening identification methods currently used at Public Health England.This paper describes a robust real-time PCR assay for the rapid, accurate identification of typhoidal and non-typhoidal Salmonella which will be invaluable for the urgent screening of isolates from symptomatic individuals, the safe processing of isolates in laboratories and for assisting the management of public health risks.

scholarly journals Real-Time PCR Assay for Differentiation of Typhoidal and Nontyphoidal Salmonella

2019 ◽  
Vol 57 (8) ◽  
Author(s):  
Satheesh Nair ◽  
Vineet Patel ◽  
Tadgh Hickey ◽  
Clare Maguire ◽  
David R. Greig ◽  
...  
Keyword(s):  
Public Health ◽  
Risk Management ◽  
Real Time ◽  
Genome Sequencing ◽  
Real Time Pcr ◽  
Enteric Fever ◽  
Rapid Identification ◽  
Whole Genome ◽  
Pcr Assay ◽  
Health Measures

ABSTRACT Rapid and accurate differentiation of Salmonella spp. causing enteric fever from nontyphoidal Salmonella is essential for clinical management of cases, laboratory risk management, and implementation of public health measures. Current methods used for confirmation of identification, including biochemistry and serotyping as well as whole-genome sequencing analyses, take several days. Here we report the development and evaluation of a real-time PCR assay that can be performed directly on crude DNA extracts from bacterial colonies for the rapid identification of typhoidal and nontyphoidal Salmonella.

scholarly journals Duplex Real-Time PCR Assay for Rapid Detection of Ampicillin-Resistant Enterococcus faecium

2004 ◽  
Vol 48 (2) ◽  
pp. 556-560 ◽  
Author(s):  
Stein Christian Mohn ◽  
Arve Ulvik ◽  
Roland Jureen ◽  
Rob J. L. Willems ◽  
Janetta Top ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Enterococcus Faecium ◽  
Rapid Detection ◽  
Resistant Bacteria ◽  
Pcr Assay ◽  
Culture Methods ◽  
Accurate Identification ◽  
Antibiotic Resistant ◽  
Highly Correlated

ABSTRACT Rapid and accurate identification of carriers of resistant microorganisms is an important aspect of efficient infection control in hospitals. Traditional identification methods of antibiotic-resistant bacteria usually take at least 3 to 4 days after sampling. A duplex real-time PCR assay was developed for rapid detection of ampicillin-resistant Enterococcus faecium (ARE). Primers and probes that are used in this assay specifically detected the d-Ala-d-Ala ligase gene of E. faecium and the modified penicillin-binding protein 5 gene (pbp5) carrying the Glu-to-Val substitution at position 629 (Val-629) in a set of 129 tested E. faecium strains with known pbp5 sequence. Presence of the Val-629 in the strain set from 11 different countries was highly correlated with ampicillin resistance. In a screening of hospitalized patients, the real-time PCR assay yielded a sensitivity and a specificity for the detection of ARE colonization of 95% and 100%, respectively. The results were obtained 4 h after samples were harvested from overnight broth of rectal swab samples, identifying both species and the resistance marker mutation in pbp5. This novel assay reliably identifies ARE 2 to 3 days more quickly than traditional culture methods, thereby increasing laboratory throughput, making it useful for rectal screening of ARE. The assay demonstrates the advantages of real-time PCR for detection of nosocomial pathogens.

scholarly journals Rapid identification of Bactrocera zonata (Dip.: Tephritidae) using TaqMan real-time PCR assay

PLoS ONE ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. e0205136 ◽  
Author(s):  
Marzieh Koohkanzade ◽  
Mohammad Zakiaghl ◽  
Manpreet K. Dhami ◽  
Lida Fekrat ◽  
Hussein Sadeghi Namaghi
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Rapid Identification ◽  
Pcr Assay ◽  
Bactrocera Zonata

scholarly journals Usefulness of Multiplex Real-Time PCR for Simultaneous Pathogen Detection and Resistance Profiling of Staphylococcal Bacteremia

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yousun Chung ◽  
Taek Soo Kim ◽  
Young Gi Min ◽  
Yun Ji Hong ◽  
Jeong Su Park ◽  
...  
Keyword(s):  
16S Rrna ◽  
Real Time ◽  
Real Time Pcr ◽  
Pathogen Detection ◽  
Methicillin Resistance ◽  
Blood Cultures ◽  
Pcr Assay ◽  
Accurate Identification ◽  
Essential Information ◽  
Methicillin Resistant

Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targetsmecA,femAspecific forS. aureus,femAspecific forS. epidermidis,16S rRNAfor universal bacteria, and16S rRNAspecific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Gram-positive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistantS. aureus(MRSA), methicillin-susceptibleS. aureus(MSSA), methicillin-resistantS. epidermidis(MRSE), methicillin-susceptibleS. epidermidis(MSSE), methicillin-resistant non-S. epidermidisCoNS (MRCoNS), and methicillin-susceptible non-S. epidermidisCoNS (MSCoNS) (κ=0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings.

A Multi-Target Real-Time PCR Assay for Rapid Identification of Meningitis-Associated Microorganisms

2012 ◽  
Vol 53 (1) ◽  
pp. 74-79 ◽  
Author(s):  
Marco Favaro ◽  
Vincenzo Savini ◽  
Cartesio Favalli ◽  
Carla Fontana
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Rapid Identification ◽  
Pcr Assay

scholarly journals Development of qualitative methods of bifidobacterium bifidum in probiotic with Real-time PCR method

2018 ◽  
Vol 1 (1) ◽  
pp. 13-17
Author(s):  
Trong Pham Nhu ◽  
Long Le Thanh ◽  
Trung Nguyen Thanh ◽  
Yen Ta Thi ◽  
Loan Pham Thi ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Dairy Products ◽  
Food Additives ◽  
Bifidobacterium Bifidum ◽  
Pcr Assay ◽  
Accurate Identification ◽  
Powdered Milk ◽  
Pcr Method

Bifidobacterium strains with probiotic effects have been widely used in dairy products, food additives and pharmaceuticals. Especially, Bifidobacterium bifidum (B. bifidum) is usually presented into food products such as functional food. However, it is difficult to detect, and quantify B. bifidum in a sample with a combination of different probiotics. In Vietnam, there is no official standard method to identify and quantify B. bifidum in the sample with the mix of probiotic species. To fulfil the requirements of a robust quality management, we have developed a quantitative real-time PCR assay based on groEL gene for accurate identification and quantification of Bifidobacterium bifidum. The developed assay allows an unambiguous speciesspecific detection. We built the real-time PCR method to detect and identify B. bifidum in functional and supplemented food with specific up to 100% and reproducibility (SR<0.25) suitable with Annex F AOAC: 2016. This real-time PCR method is rapidly and effectively than conventional method. It takes only 24 hours to detect and identify B. bifidum in compare with at least a period of 3-5 days for conventional methods. The low quantitative limit is 105 CFU/g/mL, which is consistent with probiotic and powdered milk products with a declared quality of more than 106 CFU/g/mL.

scholarly journals A Real-Time PCR Assay for Rapid Identification of Inducible and Acquired Clarithromycin Resistance in Mycobacterium abscessus

2020 ◽  
Author(s):  
Meenu Kaushal Sharma ◽  
Yanni La ◽  
Debra Janella ◽  
Hafid Soualhine
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Acquired Resistance ◽  
Rapid Identification ◽  
Mycobacterium Abscessus ◽  
23S Rrna ◽  
Pcr Assay ◽  
Constitutive Resistance ◽  
Clarithromycin Resistance ◽  
Severe Infections

Abstract Background: Mycobacterium abscessus is a rapidly growing mycobacteria involved in severe infections of the lung, skin, or soft tissue. Macrolides such as clarithromycin are the recommended first line drugs for treatment of M. abscessus infections. However, M. abscessus has dual mechanisms of resistance to macrolides, making treatment by macrolides difficult. A functional erm(41) gene confers for inducible resistance while acquired mutations on the 23S rRNA rrl gene confer for constitutive resistance.Methods: We have developed a real-time PCR assay to detect both inducible and acquired resistance to clarithromycin, and compared the results to traditional erm(41) and rrl sequencing and phenotypic susceptibility testing using Sensititre™ plates. Results: Of the total 126 M. abscessus isolates tested, truncated erm(41) was found in 23/126 (18.3%) of the samples, 27/126 (21.4%) had a T28C mutation in erm(41), and 2/126 (1.6%) had an acquired A2058C mutation in rrl. The phenotypic results correlated with the expected sequencing results in 121/126 samples (96%). Phenotypic testing compared to real-time PCR resolved 2 of these discrepancies by showing the existence of both erm(41) alleles in the isolates that sequencing missed. One culture was found to be mixed with two M. abscessus subsp. as per hsp65 sequencing and 2 isolates had discordance between molecular and phenotypic results. It was presumed that 3 isolates showed discrepancy between sequencing and real-time PCR, but one culture was mixed and other 2 detected both alleles by real-time PCR leading to 100% concordance when compared to sequencing.Conclusion: In conclusion, real-time PCR is more accurate for detection of both acquired and induced clarithromycin resistance, specifically when mixed genic profiles are present in a sample.

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