Multiplex PCR Method For Detection Research Articles

Application of a Multiplex PCR Assay for Molecular Identification of Pathogenic and Non-Pathogenic Leptospires based on lipL32 and 16S rRNA Genes.

Leptospirosis is a serious zoonotic infection and the most prevalence disease is in the tropical and subtropical region. The definitive diagnosis of Leptospirosis, caused by spirochetes of the genus Leptospira infection is already using culture methods, serological tests such as the microscopic agglutination test (MAT) and molecular detection methods (PCR) are possible. In this study, we used multiplex PCR method for detection of pathogenic and non - pathogenic Leptospira based on lipL32 and 16S rRNA genes. All serovars were obtained from the Leptospira Reference Laboratory of Microbiology Department, Razi Vaccine and Serum Research Institute, Karaj, Iran. The PCR product for the lipL32 and 16S rRNA genes was 272 bp and 240 bp respectively. The sensitivity amplification for the multiplex assay was 10-6 pg / μl for 16S rRNA gene and 10-4 pg / μl for lipL32 gene. The sensitivity for multiplex PCR was 10-3 pg / μl. The results supported the idea that multiplex PCR can be used to detect Leptospira samples. This method was also able to differentiate between saprophytic and pathogenic leptospires and was able to do so much easily than conventional methodologies. Due to the slow growth of Leptospira and the importance of time in diagnosis, molecular methods such as PCR are suggested.

Multiplex PCR method for detection of variability in genes encoding the alpha proteins of Streptococcus agalactiae

The majority of Streptococcus agalactiae strains express one or more surface-anchored proteins that vary by strain. These proteins, which are characteristic for S. agalactiae, and are able to induce protective antibodies, include the alpha C, Rib proteins, alpha-like protein 2, and alpha-like protein 3. In this study was developed multiplex PCR method for detection of genes encoding these proteins, and its occurrence within a various S. agalactiae isolates of bovine origin. Also are reported two new genes from bovine isolates of S. agalactiae amplified by PCR, encoding other putative members of the family, alphalike protein 6, and alpha-like protein 7. They contain an overall genetic organization highly similar to that of the alpha C and Rib proteins.

Multiplex PCR method for simultaneous detection of five pathogenic bacteria closely related to foodborne diseases.

In this study, we describe a multiplex PCR method for the detection of five food-relevant virulence pathogenicity genes of intestinal pathogens. Five pairs of primers were designed based on nuc gene for Staphylococcus aureus, hlyA gene of Listeria monocytogenes, ipaH gene of Shigella flexneri, lysP gene of Yersinia enterocolitica and tpi gene of Clostridium difficile. Conditions were optimized to amplify fragments of those genes simultaneously in one PCR amplification. After developing and optimizing the multiplex PCR reaction system, the specificity and sensitivity of the multiple PCR assays were evaluated. The optimized program is also applied to retail meat for testing. The result indicated that when the annealing temperature was 54°C and the primer concentrations of S. aureus, L. monocytogenes, S. flexneri, Y. enterocolitica and C. difficile are 10, 10, 5, 3 and 2μM, the five strains could expand 484, 345, 204, 156, 88bp of clear fragments, respectively. So was the multiple PCR in artificially contaminated beef produce. All cultures were cultured and separated by traditional methods. The multiplex PCR method offers a rapid, simple, and accurate identification of pathogens and could be used in food safety investigations, clinical diagnosis as well as for the surveillance of the spreading determinants of pathogens in epidemiological studies.

A multiplex PCR method for detection of five animal species in processed meat products using novel species-specific nuclear DNA sequences

The continuous development of fast and simple new methods to identify animal-derived ingredients is very important for the authentication of meat products. This study intended to develop a multiplex PCR method using new species-specific nuclear DNA (nDNA) sequences for the detection of ingredients derived from sheep/goat, bovine, chicken, duck and pig in meat products. Sequence alignment analysis in 53 species showed high specificity of species-specific nDNA. Species-specific primers were designed on the conservative region of each species-specific nDNA sequence. The specificity and conservation of the sequences and primers were verified by PCR reaction and sequencing with the limit of detection down to 0.5 ng. Then, a species-specific multiplex PCR method was developed and optimized to simultaneously detect sheep/goat (237 bp), bovine (223 bp), chicken (192 bp), duck (168 bp) and pig (154 bp) in one reaction. Various processed meat products containing one or more animal-derived ingredients were detected by the developed multiplex PCR method, and the results were consistent with their labeled meat species. Our study provides a fast and simple detection method for regulating labeling of animal-derived ingredients in meat products.

New Drugs for Multidrug-Resistant Gram-Negative Organisms: Time for Stewardship.

A gradual rise in drug-resistant trends among Gram-negative organisms, especially carbapenem-resistant (CR) Enterobacteriaceae (CRE), CR-Pseudomonas aeruginosa, and extensively-drug-resistant (XDR) Acinetobacter baumannii, poses an enormous threat to healthcare systems worldwide. In the last decade, many pharmaceutical companies have devoted enormous resources to the development of new potent antibiotics against XDR Gram-negative pathogens, particularly CRE. Some of these novel antibiotics against CRE strains are β-lactam/β-lactamase-inhibitor combination agents, while others belong to the non-β-lactam class. Most of these antibiotics display good in vitro activity against the producers of Ambler class A, C, and D β-lactamase, although avibactam and vaborbactam are not active in vitro against metallo-β-lactamase (MβL) enzymes. Nevertheless, in vitro efficacy against the producers of some or all class B enzymes (New Delhi MβL, Verona integron-encoded MβL, etc) has been shown with cefepime-zidebactam, aztreonam-avibactam, VNRX-5133, cefiderocol, plazomicin, and eravacycline. As of Feburary 2019, drugs approved for treatment of some CRE-related infections by the US Food and Drug Administration included ceftazidime-avibactam, meropenem-vaborbactam, plazomicin, and eravacycline. Although active against extended-spectrum and AmpC β-lactamase-producing Enterobacteriaceae, delafloxacin does not show in vitro activity against CRE. Murepavadin is shown to be specifically active against CR- and colistin-resistant P. aeruginosa strains. Despite successful development of novel antibiotics, strict implementation of an antibiotic stewardship policy in combination with theuse of well-established phenotypic tests and novel multiplex PCR methods for detection of the most commonly encountered β-lactamases/carbapenemases in hospitals is important for prescribing effective antibiotics against CRE and decreasing the resistance burden due to CRE.

Multiplex PCR methods for detection of several viruses associated with canine respiratory and enteric diseases.

Viral respiratory and intestinal infections are the most common causes of canine viral illness. Infection with multiple pathogens occurs in many cases. Rapid diagnosis of these multiple infections is important for providing timely and effective treatment. To improve diagnosis, in this study, two new multiplex polymerase chain reactions (mPCRs) were developed for simultaneous detection of canine respiratory viruses (CRV) and canine enteric viruses (CEV) using two separate primer mixes. The viruses included canine adenovirus type 2 (CAV-2), canine distemper virus (CDV), canine influenza virus (CIV), canine parainfluenza virus (CPIV), canine circovirus (CanineCV), canine coronavirus (CCoV) and canine parvovirus (CPV). The sensitivity of the mPCR results showed that the detection limit of both mPCR methods was 1×104 viral copies. Twenty nasal swabs (NS) and 20 anal swabs (AS) collected from dogs with symptoms of respiratory disease or enteric disease were evaluated using the novel mPCR methods as a clinical test. The mPCR protocols, when applied to these respiratory specimens and intestinal samples, could detect 7 viruses simultaneously, allowing rapid investigation of CRV (CAV-2, CDV, CIV and CPIV) and CEV (CAV-2, CanineCV, CCoV and CPV) status and prompt evaluation of coinfection. Our study provides an effective and accurate tool for rapid differential diagnosis and epidemiological surveillance in dogs.

Clostridium Perfringens Spores in Polish Honey Samples.

IntroductionThe aim of this study was examination of honey samples collected from apiaries situated in all Polish provinces for occurrence of Clostridium spp., especially C. perfringens.Material and MethodsThe study was carried out on 240 honey samples (15 samples/province). Estimation of Clostridium titre, its cultures and C. perfringens isolate characterisation were performed according to the standard PN-R-64791:1994. A multiplex PCR method for detection of genes coding cpa (α toxin), cpb (β), cpb2 (β2), etx (ε), iap (ι), and cpe (enterotoxin) toxins was used.ResultsClostridium spp. was noticed in 56% (136/240) of samples, and its titres ranged between 0.1 g and 0.001 g. Clostridium perfringens occurrence was evidenced in 27.5% (66/240) of samples. All isolates were classified to toxinotype A.ConclusionsEvidence of a high number of positive samples with occurrence of Clostridium spp. indicates a potential risk to consumers’ health. The infective number of Clostridium spp. is unknown; however, the obtained results have shown that a risk assessment on the entire honey harvesting process should be made in order to ensure microbiological safety. Moreover, a detailed study should be undertaken on the antibiotic resistance of C. perfringens isolates from honey samples.

Simple and fast multiplex PCR method for detection of species origin in meat products.

Identification of animal species is one of the major concerns in food regulatory control and quality assurance system. Different approaches have been used for species identification in animal origin of feedstuff. This study aimed to develop a multiplex PCR approach to detect the origin of meat and meat products. Specific primers were designed based on the conserved region of mitochondrial Cytochrome C Oxidase subunit I (COX1) gene. This method could successfully distinguish the origin of the pig, camel, sheep, donkey, goat, cow, and chicken in one single reaction. Since PCR products derived from each species represent unique molecular weight, the amplified products could be identified by electrophoresis and analyzed based on their size. Due to the synchronized amplification of segments within a single PCR reaction, multiplex PCR is considered to be a simple, fast, and inexpensive technique that can be applied for identification of meat products in food industries. Nowadays, this technique has been considered as a practical method to identify the species origin, which could further applied for animal feedstuffs identification.

High throughput multiplex-PCR for direct detection and diagnosis of dermatophyte species, Candida albicans and Candida parapsilosis in clinical specimen

We have developed and validated a multiplex-PCR method for detection of dermatophyte spp., Candida albicans and parapsilosis for routine diagnostics. Our m-PCR showed excellent concordance with culture results in 475 clinical samples. Through the rapid diagnosis by our m-PCR, clinicians are able to initiate adequate antimycotic therapy much earlier.

A multiplex PCR method for detection of Aspergillus spp. and Mycobacterium tuberculosis in BAL specimens

The aim of this study was the detection of Aspergillus species and Mycobacterium tuberculosis together in bronchoalveolar lavage (BAL) using of multiplex PCR. In this study, from September 2012 until June 2013, 100 bronchoalveolar lavage (BAL) specimens were collected from patients suspected of tuberculosis (TB). After the direct and culture test, multiplex PCR were utilized in order to diagnose Aspergillus species and M.tuberculosis. Phenol-chloroform manual method was used in order to extract DNA from these microorganisms. Aspergillus specific primers, M.tuberculosis designed primers and beta actin primers were used for multiplex PCR. In this study, by multiplex PCR method, Aspergillus species were identified in 12 samples (12%), positive samples in direct and culture test were respectively 11% and 10%. Sensitivity and specificity of this method in comparison to direct test were respectively 100% and 98.8%, also sensitivity and specificity of this method in comparison to culture test were respectively 100% and 97.7%. In this assay, M.tuberculosis was identified in 8 samples (8%). Mycobacterium-positive samples in molecular method, direct and culture test were respectively 6%, 5% and 7%. Sensitivity and specificity of PCR method in comparison to direct test were 80% and 97.8% also sensitivity and specificity of this method in comparison to culture test was 71.4% and 98.9%. In the present study, multiplex PCR method had higher sensitivity than direct and culture test in order to identify and detect Aspergillus, also this method had lower sensitivity for identification of M.tuberculosis, suggesting that the method of DNA extraction was not suitable.

Comparison of Direct Culture, Immunomagnetic Separation/culture, and Multiplex PCR Methods for Detection of <i>Salmonella</i> in Food

Comparison of Direct Culture, Immunomagnetic Separation/culture, and Multiplex PCR Methods for Detection of <i>Salmonella</i> in Food

Identification of clinical aeromonas species by rpoB and gyrB sequencing and development of a multiplex PCR method for detection of Aeromonas hydrophila, A. caviae, A. veronii, and A. media.

Conventional identification of Aeromonas species based on biochemical methods is challenged by the heterogeneous nature of the species. Here, we present a new multiplex PCR method directed toward the gyrB and rpoB genes that identifies four Aeromonas species, A. hydrophila, A. media, A. veronii, and A. caviae, and we describe the application of this method on a Danish strain collection.

Design of a multiplex PCR method for detection of toxigenic-pathogenic in Vibrio cholerae

ObjectiveTo study virulence and regulatory genes (hlyA, ctxB, tcpI) in clinical strains of Vibrio cholerae (V. cholerae), simultaneously. MethodsThree important genes, tcpI, hlyA and ctxB were used for detection of toxigenic and pathogenic V. cholera by chain reaction assay method. ResultsAccording to the results of the PCR, the incidence of hlyA, tcpI, and ctxB genes in clinical isolates was obtained as 94.7% (72 sample), 90.8% (69 sample), and 92.1% (70 sample), respectively. Five strains possessed all genes except ctxB, six strains possessed all genes except tcpI, four strains possessed all genes except hlyA, one strain possessed only hlyA and 60 strains contained a combination of three genes, Including hlyA, ctxB and tcpI. ConclusionsResult show that this method could be reliable to detect toxigenic-pathogenic strains of V. cholerae in Iran.

In-House Validation of Multiplex PCR Method for Detection of Clostridium Botulinum in Food and Feed

Abstract The aim of this study was to perform an in-house validation of multiplex PCR method for C. botulinum detection in food and feed samples. The study was carried out on food and feed matrixes artificially contaminated by spores of C. botulinum reference strains. The following characteristic parameters for qualitative detection were estimated: limit of detection expressed as LOD50 according to the Spearman-Kärber formula, specificity, sensitivity, and accuracy according to the PN-EN ISO 16140:2004. The validated method showed high specificity. Specific PCR products were revealed only for DNA obtained from samples contaminated with C. botulinum spores. PCR inhibition was observed, especially during examination of contaminated feed. The calculated LOD50 for feed was nearly 10 times higher than for food. The implemented method enables to obtain test results during 3 d without time- consuming process of isolation and proving the ability of strains to produce botulinum toxins.

Intra- and inter-laboratory evaluation of an improved multiplex-PCR method for detection and typing of Salmonella

We developed and evaluated a multiplex-PCR method for rapid detection of the most common Salmonella serovars in both developed and developing countries. Additionally, the stability of the premixed reagents at high room temperature was studied. Fifty-two Salmonella strains belonging to the collections of the University of Sassari, Italy, and to the University of the Basque Country, Spain, and a collection of a hundred blinded strains, were used to evaluate the multiplex-PCR. Primers targeting genes STY1599 and fliC were selected, and the method was evaluated both intra and inter-laboratories. The inter-laboratory reproducibility was 95.92%, with a kappa index of 0.757 that indicates a substantial agreement and a high accuracy (80.81%). The sensitivity, specificity, accuracy and precision indexes for the Salmonella genus and S. Typhi targets were maximum, although the targets for Paratyphi A, Typhimurium and Enteritidis showed less accuracy. During a seven-week period, hot-start multiplex-PCR runs were performed with reagents mixed with wax to test their stability at 30ºC, and no significant variation in the patterns of amplification was observed. An improved multiplex-PCR for rapid detection of the most common serovars of Salmonella operable in both developed and developing countries has been designed and tested intra and inter-laboratories. Following a careful optimization protocol will not only allow the confirmation of any suspicious colony by the amplification of the Salmonella genus target, but also the preliminary adscription to the prevalent serovars. Premixed reagents with wax facilitate the throughput and stability of reagents at high room temperatures.

Development of multiplex and construct specific PCR assay for detection of cry2Ab transgene in genetically modified crops and product

An efficient detection system for trait validation and screening of GMOs is a much sought after procedure, which could also help in regulatory compliance. Currently, in India, a number of cry2Ab transgene carrying GM crops are undergoing field trial i.e., MON15985 cotton, Bt rice, Bt okra, Bt corn, Bt brinjal, Bt potato and Bt tomato. In this study, we report a qualitative assay for detection for cry2Ab (326 bp). Further, the amplification compatibility with promoter, p35S (195 bp), terminator, t-nos (180 bp) and marker gene, npt II (215 bp) was also confirmed using Bt cotton event MON15985 as reference material. The detection sensitivity was 0.1% that is far below the requirement of the stringent European Union (EU) regulations of 0.9%. The target DNA when spiked with either MECH-12 (cry1Ac), RR-soya (epsps) or MON-810 (cry1Ab) showed no inhibitory effect on cry2Ab detection. Moreover, the cry2Ab specific transgene construct (1.9 kb) was amplified and its identity confirmed by a nested PCR. Hence, a comprehensive multiplex PCR method for detection of cry2Ab gene in a GM crop/products was established. This is possibly a first report showing concurrent amplification of cry2Ab transgene, promoter, terminator and marker gene.

METHYLENETETRAHYDROFOLATE REDUCTASE (MTHFR) MULTIPLEX – PCR METHOD

Introduction: Gene polymorphisms in human methylenetetrahydrofolate reductase (MTHFR) have been linked to the disorders of folate metabolism, and may contribute to such disease as neural tube defect, coronary heart disease, venous thrombosis, and several types of cancers. Methodology: We have modified our current real-time PCR method (Clin Biochem 2000;33:535-539.) for the detection of the MTHFR c.677C > T variant to a real-time multiplex-PCR method for detection of MTHFR c.1298A > C and c.677C > T variants on a LightCycler 1.2. Our multiplex method is partly based on that of Agarwal et al.(J Mol Diag 2007;9:345). Results: The genotyping results of c.677C > T variant analyzed by both methods were in agreement. All samples analyzed for the c.1298A > C variant by the Multiplex-PCR method gave clear-cut results. The LightCycler multiplex method was validated with 14 specimens previously genotyped by restriction fragment length polymorphism at Montreal Children’s Hospital. All results were in agreement except for one sample that failed to amplify. There was no significant difference in Tm between the Multiplex-PCR procedure and the previously reported Tm’s for both variants. When run alone but not as a multiplex, the progress curve of the c.1298A > C variant exhibited the “hook effect”. Asymmetric amplification was found to reduce this effect. Conclusions: The multiplex assay is reliable, economical, fast and simple method to perform as compared with RFLP technique. Asymmetric PCR is a helpful tool to minimize the hook effect.

A multiplex PCR method for detection of Clavibacter michiganensis subsp. michiganensis with co-amplification of its host DNA

A multiplex PCR assay system was developed for the detection of Clavibacter michiganensis subsp. michiganensis (Cmm), which combined two tests in one reaction mixture. Cmm-specific primers PSA-4/PSA-R and Solanum lycopersicum-specific primers NS-7-F/NS- 8-R (internal PCR control primer) were combined in one PCR reaction mixture with Cmm and plant DNA as template. The primer sets could amplify the target product successfully. Different combinations and concentrations of primers and annealing temperatures were tested, respectively. The detection level of the optimized multiplex PCR assay was up to 5×102 cfu·mL−1. To verify the applicability of this system, it was employed to detect Cmm in tomato seeds and plantlet samples. Seeds mixed with Cmm and diseased plantlets were detected successfully. The multiplex PCR system will avoid false-negative results and provide a reliable method for the detection of Cmm.

Standard and real-time multiplex PCR methods for detection of trimethoprim resistance dfr genes in large collections of bacteria

Two multiplex PCR (mPCR) methods were developed to screen large collections of trimethoprim-resistant Escherichia coli isolates for the most prevalent resistance determinants. Five common integron-carried genes (dfrA1, dfrA5, dfrA7, dfrA12 and dfrA17) were selected as PCR targets. Primers and conditions for standard mPCRs and real-time mPCRs were selected and tested. Two protocols using essentially the same primer pairs were established. The standard mPCR protocol also included an internal control targeting the E. coli 16S rRNA gene. Both protocols proved to be sensitive and specific for detection of the five selected genes. Screening of three different collections of clinical urinary and blood isolates (n = 368) with the two multiplex methods revealed that the five dfr genes accounted for 75-86% of trimethoprim resistance. The standard mPCR is useful and accessible for most laboratories, while the real-time mPCR requires additional equipment and expensive reagents, but is very convenient for high-throughput screening of large collections of bacterial isolates.

PCR method for the detection of potential ochratoxin-producing Aspergillus species in coffee beans

Ochratoxin A (OA) is a nephrotoxic and carcinogenic mycotoxin that has been found in cereal and food commodities. Currently, Aspergillus carbonarius, A. niger and A. ochraceus have been recognized as the species responsible for OA in coffee beans. With the aim of developing multiplex-PCR for detection of these species in coffee bean samples, we first developed specific primers for A. niger detection. The primer designed (OPX7 372) provided an amplicon of 372 pb in all A. niger stricto sensu isolates. The PCR assay developed for A. niger identification in pure culture was also successfully used for detecting this species in coffee beans. No cross-reaction was observed using DNA from coffee beans inoculated with closely related black aspergilli species. A multiplex-PCR method for detection of A. carbonarius, A. niger and A. ochraceus species in coffee beans was developed. From a single assay this method detected the amplicons of 809, 372, and 260 pb that represent the three most ochratoxigenic species found in coffee bean samples, i.e., A. carbonarius, A. niger and A. ochraceus, respectively.