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At least 415 records · Page 23Linked to original sources

Development of a single-round and multiplex PCR method for the simultaneous detection of Babesia caballi and Babesia equi in horse blood.

With the aim of developing more simple diagnostic alternatives, a differential single-round and multiplex polymerase chain reaction (PCR) method was designed for the simultaneous detection of Babesia caballi and Babesia equi, by targeting 18S ribosomal RNA genes. The multiplex PCR amplified DNA fragments of 540 and 392 bp from B. caballi and B. equi, respectively, in one reaction. The PCR method evaluated on 39 blood samples collected from domestic horses in Mongolia yielded similar results to those obtained from confirmative PCR methods that had been established earlier. Thus, the single-round and multiplex PCR method offers a simple tool for the differential diagnosis of B. caballi and B. equi infections in routine diagnostic laboratory settings as well as in epidemiological studies.

Animals↗

Reverse transcription-competitive multiplex PCR improves quantification of mRNA in clinical samples--application to the low abundance CFTR mRNA.

BACKGROUND: To monitor gene therapy, we wished to quantify cystic fibrosis transmembrane conductance regulator (CFTR) mRNA. We developed a PCR-based method to measure CFTR mRNA in clinical samples. METHODS: Expression was determined by reverse transcription-competitive multiplex PCR (RCMP) for CFTR and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) transcripts, and for serial dilutions of two internal cDNA standards consisting of CFTR and GAPDH mutants containing short deletions. The RCMP used simultaneous amplification of the gene of interest with a reporter gene in one reaction tube. The expression of CFTR was calculated with reference to the amount of GAPDH to correct for variations in initial RNA loading. RESULTS: Amplification of cDNAs derived from different amounts of RNA (1-4 microgram) gave similar GAPDH/CFTR ratios, with a coefficient of variation (CV) below 7.5%. RCMP was applied on nasal and bronchial brushings and shows a high variability of CFTR expression in non-cystic fibrosis donors. CONCLUSION: This method is precise and reproducible and advantageous for use with limited amounts of tissue, such as from biopsies or from nasal or bronchial brushings.

Bronchi↗

Swiss population data on three tetrameric short tandem repeat loci--VWA, HUMTHO1, and F13A1--derived using multiplex PCR and laser fluorescence detection.

Allele and genotype frequencies for 3 tetrameric short tandem repeat loci VWA, HUMTHO1, and F13A1 were determined in a Swiss population sample using multiplex PCR and subsequent electrophoresis in DNA sequencing gels processed by automated laser fluorescence detection. The technique allows single base pair resolution and rapid typing, with a concomitant reduction in the potential for human transcriptional typing errors. All loci meet Hardy-Weinberg expectations. In addition, there is little evidence for association of alleles among the 3 loci. The allelic frequency data can be used in forensic analyses and paternity tests to estimate the frequency of a multiple STR locus DNA profile in the Swiss population.

Alleles↗

Novel multiplex PCR assay for detection of the staphylococcal virulence marker Panton-Valentine leukocidin genes and simultaneous discrimination of methicillin-susceptible from -resistant staphylococci.

We developed a new multiplex PCR assay for detection of Panton-Valentine leukocidin virulence genes and simultaneous discrimination of methicillin-susceptible from -resistant staphylococci. This assay is simple, rapid, and accurate and offers the potential for prompt detection of newly emerging community-associated methicillin-resistant Staphylococcus aureus.

Alberta↗

Multiplex PCR for screening of integrons in bacterial lysates.

Bacterial integrons are a useful PCR amplification target in epidemiological surveys of bacterial antibiotic resistance, and a variety of primers have been published. We describe multiplex PCR methodology to test for classes 1, 2 and 3 integron-associated integrases in boiled lysates of Gram-negative bacteria. We report on performance in Acinetobacter spp. (n=50), Enterobacteriaceae (n=76), Pseudomonas aeruginosa (n=15), Bacteroidesspp. (n=69), and in undifferentiated mixed cultures derived from perineal swabs (n=50) and endotracheal aspirates (n=8). This method achieved 100% sensitivity and specificity in simple lysates made from a range of bacteria, without requiring DNA extraction, and is recommended as an efficient screening tool for surveys of integron cassettes.

Acinetobacter↗

Semiquantitative and qualitative assessment of B-lymphocyte V H repertoire by a fluorescent multiplex PCR.

We established a new tool to perform semiquantitative and qualitative screening for V(H) gene usage frequency during IgH rearrangements in human B-lymphocytes. In two separate multiplex PCRs, the rearranged VDJ regions were amplified with V(H) family-specific primers labeled with different fluorescent dyes (FAM, HEX, NED, or ROX). The relative amount of each of the particular V(H) family products and their ratios were determined by fragment analysis on a ABI PRISM 377 sequencer. We verified that the fluorescent multiplex PCR (FMPCR) shows high specificity and sensitivity, acceptable reproducibility and reliability. Data obtained were well in agreement with results revealed by sequencing following single-cell PCR. Ten healthy volunteers showed a comparable semiquantitative V(H) family distribution. The FMPCR also correctly detected a monoclonal peak in a CLL patient. Thus, labeling primers with various fluorescent dyes allows for an assessment of V(H) family usage and an immediate determination of the involved V(H) gene family if any clonal peaks are present. This method provides a quick, easy, and reliable tool for V(H) repertoire screening of larger populations of patients suffering from diseases with changes in the V(H) repertoire allowing for selection of cases worth a more detailed and cumbersome sequence analysis later on.

Adult↗

Identification of Actinobacillus actinomycetemcomitans serotypes by multiplex PCR.

Oligonucleotide primers specific for gene clusters involved in the biosynthesis of serotype-specific polysaccharide antigens were designed to identify Actinobacillus actinomycetemcomitans serotypes a to e using the multiplex PCR. This method may be useful for serotype-specific genotyping rapidly and directly from clinical samples containing various organisms.

Actinobacillus Infections↗

Rapid and reliable detection and identification of GM events using multiplex PCR coupled with oligonucleotide microarray.

To devise a rapid and reliable method for the detection and identification of genetically modified (GM) events, we developed a multiplex polymerase chain reaction (PCR) coupled with a DNA microarray system simultaneously aiming at many targets in a single reaction. The system included probes for screening gene, species reference gene, specific gene, construct-specific gene, event-specific gene, and internal and negative control genes. 18S rRNA was combined with species reference genes as internal controls to assess the efficiency of all reactions and to eliminate false negatives. Two sets of the multiplex PCR system were used to amplify four and five targets, respectively. Eight different structure genes could be detected and identified simultaneously for Roundup Ready soybean in a single microarray. The microarray specificity was validated by its ability to discriminate two GM maizes Bt176 and Bt11. The advantages of this method are its high specificity and greatly reduced false-positives and -negatives. The multiplex PCR coupled with microarray technology presented here is a rapid and reliable tool for the simultaneous detection of GM organism ingredients.

Brassica rapa↗

Identification of substrains of BCG vaccine using multiplex PCR.

Current methods for determining the identity of substrains of Mycobacterium bovis BCG (BCG) vaccine are labour intensive, or provide only limited substrain differentiation. In this paper we describe a multiplex PCR that distinguishes between M. tuberculosis (TB) and M. bovis and the non-pathogenic BCG strain, and also subdivides the BCG vaccine substrains investigated into seven distinct fingerprints based on six target regions in the DNA. This test is specific, rapid, reproducible and portable and is proposed as a novel test for BCG vaccine control. It offers substantial advantages over the methods currently in use. Using this test we have characterised a number of commercial BCG vaccines.

BCG Vaccine↗

Identification of New World Leishmania species from Peru by biochemical techniques and multiplex PCR assay.

We have characterized diverse strains or species of Leishmania isolated in humans that are currently circulating throughout Peru, by means of isoenzymatic characterization, kDNA analysis by restriction enzymes, and multiplex PCR assay. The cluster analysis gave five groups. Cluster 1 includes L. (L.) donovani together with the isolates LP4 and LP7, forming the donovani complex. Thus, this complex corresponds to the New World visceral form, L. (L.) chagasi. Cluster 2 is formed by the isolates LP1-LP3, LP6, LP10, LP9, and LP11, phylogenetically intermediate between Cluster 1 and Cluster 3, or they can be treated as hybrids. Cluster 3 is divided into two subgroups: one formed by L. (V.) peruviana, together with the isolates LP14 and LP5, and the second one formed by L. (V.) brazilensis and the isolate LP8. These two subgroups form part of the brazilensis complex. The three strains of L. (L.) infantum [L. (L.) infantum I and II and la LSI] make up Cluster 4. In Cluster 5, we include the three Mexican strains (LM1-LM3) forming one subgroup while we would place L. (L.) amazonensis in another subgroup. These two subgroups would comprise the complex mexicana.

Animals↗

[Detection of microsatellite instability in primary gastric cancer using fluorescence-labelled primers multiplex PCR].

To assess the role of microsatellite instability(MSI) on chromosome 19 in the carcinogenesis of gastric cancer. 26 microsatellite markers on chromosome 19 were amplified by Fluorescence-Labelled Primers Multiplex PCR in 44 paired gastric cancer tissues for MSI. The amplified fragments ran in PAGE gel by ABI 377 sequencer and the gel images were analyzed by GeneScan and Genotyper. Meanwhile, MSI of four of all microsatellite sites were also analyzed using PCR-SSLP-silver stain method. MSI was observed in 22 of 26(84.62%) microsatellite sites. D19S402 showed the highest frequency(22.73%). The total frequency of MSI was 8.3%. In 44 gastric cancer samples, 34(77.27%) cases showed MSI at one or more than one site. MSI, as a possible mechanism of carcinogenesis, might play an important role in human primary gastric cancer. MSI detections will become an integral part of the routine classification of all gastrointestinal tumors in the very near future.

Fluorescence↗

A multiplex PCR for the detection of Brucella spp. and Leptospira spp. DNA from aborted bovine fetuses.

Bovine brucellosis and leptospirosis are important causes of bovine abortion around the world. Both diseases can be serologically diagnosed, but many factors may cause false positive and negative results. Direct methods based on bacteriological isolation are usually employed, but they are difficult, time consuming and dangerous. Monoplex polymerase chain reaction (PCR) have been successfully described for the detection of Brucella spp. and Leptospira spp. Aiming at improvement in the direct diagnosis, a multiplex PCR (mPCR) for the detection of these agents in aborted bovine fetuses is described. The detection threshold of the mPCR was evaluated in experimentally contaminated bovine clinical samples using a conventional proteinase K/SDS or a boiling-based extraction protocols. The mPCR was applied to two groups of clinical samples: 63 episodes of bovine abortion and eight hamsters experimentally infected with Leptospira interrogans serovar pomona. Adopting microbiological isolation as reference, the test showed a sensitivity of 100% in both groups of clinical samples. Seven samples collected from bovine fetuses were Brucella spp. culture negative but showed positive results in mPCR. Regarding Leptospira spp. detection, similar results were observed in three bovine clinical samples. All hamsters infected with Leptospira were positive in both microbiological culture and mPCR. The boiling extraction protocol showed better results in some clinical samples, probably by the removal of PCR inhibitors by heat treatment. The high sensitivity, simplicity and the possibility of detection of both bacteria in a single tube reaction support the use of the mPCR described in the routine diagnosis.

Abortion, Veterinary↗

The analysis of three short tandem repeat (STR) loci in the Slovene population by multiplex PCR.

Allele frequencies for three tetrameric short tandem repeat (STR) loci D3S1358, HUMVWA, and HUMFGA were determined in a Slovene Caucasian population sample. DNA samples from a total of 221 Slovenes were amplified by multiplex PCR using the commercial kit AmpFISTR Blue (Perkin-Elmer). Separation and detection of the amplified STR fragments were carried out using a 377 automated genetic analyzer (Applied Biosystem Division/Perkin Elmer). Seven alleles at the D3S1358 locus, 8 alleles at the HUMVWA31A locus, and 13 alleles at the HUMFGA locus were observed. A deviation from Hardy-Weinberg equilibrium was observed, only at the HUMVWA31A locus (p = 0.045, exact test). The departure at this locus was not significant after Bonferroni correction. There were no detectable departures between pairwise comparisons of the loci. The combined power of discrimination for all three loci is 0.9998, and the power of exclusion is 0.9526. The observed allele frequencies for the loci D3S1358, HUMVWA31A, and HUMFGA are similar to those in European and U.S. Caucasian populations.

Alleles↗

Correlation between the resistance genotype determined by multiplex PCR assays and the antibiotic susceptibility patterns of Staphylococcus aureus and Staphylococcus epidermidis.

Clinical isolates of Staphylococcus aureus (a total of 206) and S. epidermidis (a total of 188) from various countries were tested with multiplex PCR assays to detect clinically relevant antibiotic resistance genes associated with staphylococci. The targeted genes are implicated in resistance to oxacillin (mecA), gentamicin ¿aac(6')-aph(2"), and erythromycin (ermA, ermB, ermC, and msrA). We found a nearly perfect correlation between genotypic and phenotypic analysis for most of these 394 strains, showing the following correlations: 98% for oxacillin resistance, 100% for gentamicin resistance, and 98.5% for erythromycin resistance. The discrepant results were (i) eight strains found to be positive by PCR for mecA or ermC but susceptible to the corresponding antibiotic based on disk diffusion and (ii) six strains of S. aureus found to be negative by PCR for mecA or for the four erythromycin resistance genes targeted but resistant to the corresponding antibiotic. In order to demonstrate in vitro that the eight susceptible strains harboring the resistance gene may become resistant, we subcultured the susceptible strains on media with increasing gradients of the antibiotic. We were able to select cells demonstrating a resistant phenotype for all of these eight strains carrying the resistance gene based on disk diffusion and MIC determinations. The four oxacillin-resistant strains negative for mecA were PCR positive for blaZ and had the phenotype of beta-lactamase hyperproducers, which could explain their borderline oxacillin resistance phenotype. The erythromycin resistance for the two strains found to be negative by PCR is probably associated with a novel mechanism. This study reiterates the usefulness of DNA-based assays for the detection of antibiotic resistance genes associated with staphylococcal infections.

Anti-Bacterial Agents↗

Multiplex PCR assay simplifies serotyping and sequence typing of Listeria monocytogenes associated with human outbreaks.

Listeria monocytogenes serotypes 1/2a and 4b are responsible for the majority of cases of human listeriosis worldwide. In this study, a multiplex PCR assay was developed to allow rapid identification and easily interpretable differentiation of serotypes 1/2a and 4b from other serotypes of L. monocytogenes by simultaneously targeting two virulence genes (inlB and inlC) and two serotype-specific genes (ORF2372 and Imo0171). A subsequent gel extraction and sequence typing analysis of the highly polymorphic intragenic regions in inlB and inlC simplified a previously developed multi-virulence-locus sequence typing scheme and provided discriminatory power for subtyping L. monocytogenes similar to pulsed-field gel electrophoresis analysis.

Bacterial Typing Techniques↗

Sequential multiplex PCR approach for determining capsular serotypes of Streptococcus pneumoniae isolates.

Accurate serotyping is essential to monitor the changes in the seroepidemiology of Streptococcus pneumoniae. We devised a simple and schematic sequence-based system of seven multiplex PCRs, in a sequence order based upon Active Bacterial Core surveillance (ABCs) serotype distribution during 2002 to 2003, to reliably deduce specific pneumococcal serotypes. A total of 421 isolates from ABCs were randomly chosen to evaluate this system. Two hundred twenty-nine of the isolates (54.3%) were specifically assigned 1 of 17 serotypes by the multiplex PCR system, with the results in complete concordance with conventional serotyping. One hundred seventy-two additional isolates (40.9%) were assigned to 11 specific sets of 2 to 4 serotypes that with one exception (serotypes 6A and 6B) consisted of the single frequently occurring targeted serotype and 1 to 3 additional rare serotypes primarily within the same serogroup as the targeted serotype. Only 20 isolates (4.8%) could not be assigned specific serotypes or serotype sets, since they were either of rare serotypes not included in the assay design or were nonserotypeable. Overall, we found this system to be highly reliable, with the potential to greatly reduce our reliance upon conventional serotyping. Especially important is the capability of this system to give serotype-determining potential to any facility that lacks the expensive typing sera and expertise needed for conventional serotyping yet has the modest equipment necessary for DNA amplification and electrophoresis.

Bacterial Capsules↗

Allele distribution at nine STR loci--D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317 and D7S820--in the Japanese population by multiplex PCR and capillary electrophoresis.

Nine tetranucleotide short tandem repeat (STR) loci, D3S1358, vWA, FGA TH01, TPOX, CSF1PO, D5S818, D13S317 and D7S820, were analyzed in the Japanese population with a newly released kit for personal identification using multiplex PCR with fluorescent-labeled primers following capillary electrophoresis. The observed heterozygosities were 0.67, 0.77, 0.82, 0.61, 0.62, 0.73, 0.78, 0.81 and 0.74, respectively, and the combined discrimination power of the nineplex was 0.9999999991. None of the nine loci deviated from Hardy-Weinberg equilibrium expectations using the chi-square test, homozygosity test, likelihood ratio test and exact test after the grouping of the alleles. The nine STR loci allele frequencies were significantly different from those of other ethnic populations.

Alleles↗