Rapid identification and differentiation of fungal DNA in dermatological specimens by LightCycler PCR

2004 ◽  
Vol 53 (12) ◽  
pp. 1207-1214 ◽  
Author(s):  
Ralf Gutzmer ◽  
Susanne Mommert ◽  
Uta Küttler ◽  
Thomas Werfel ◽  
Alexander Kapp

The aim was to develop a LightCycler PCR method for the rapid detection and differentiation of fungal DNA in dermatological specimens such as skin scales and skin swabs. LightCycler PCR assays were established for seven primer sets specific for fungal DNA. For each primer set LightCycler melting points were defined by amplification of DNA from 21 fungi and sensitivity was determined by amplification of serial dilutions of fungal DNA. A protocol was established that allows detection and differentiation of mould and yeast DNA with one highly sensitive PCR reaction by assessment of LightCycler melting points. Two subsequent LightCycler PCR reactions and one RFLP reaction allowed the differentiation of dermatophytes and non-dermatophyte moulds and the subclassification of yeasts. Analysis of clinical samples from 38 patients with fungal skin diseases provided conclusive new diagnostic information in 9/38 cases (23.7 %) by this PCR protocol that was not equally provided by direct microscopy and mycological culture. Thus the LightCycler PCR protocol established here represents a rapid diagnostic tool that aids in the diagnosis of fungal skin disease in a substantial number of patients.

2009 ◽  
Vol 58 (7) ◽  
pp. 878-883 ◽  
Author(s):  
Wafa Habbal ◽  
Fawza Monem ◽  
Barbara C. Gärtner

Standardization of human cytomegalovirus (CMV) PCR is highly recommended. As primer design is essential for PCR sensitivity, this study evaluated all published CMV primer pairs to identify the most sensitive for single-round real-time PCR. PubMed (1993–2004) was searched for original papers aimed at CMV PCR. Fifty-seven papers were identified revealing 82 different primer pairs. Of these, 17 primer sets were selected for empirical study, as they were either used in real-time PCR or were evaluated comparatively by conventional PCR. After optimizing the PCR conditions, these primer sets were evaluated by real-time PCR using a SYBR Green format. Analytical sensitivities were assessed by testing the reference standard CMV strain AD169. A blast search was performed to identify mismatches with published sequences. Additionally, 60 clinical samples were tested with the three primer sets showing highest analytical sensitivity and the best match to all CMV strains. Three primer sets located in the glycoprotein B (UL55) gene region were found to be the most sensitive using strain AD169. However, two of these showed a considerable number of mismatches with clinical isolates in a blast search. Instead, two other pairs from the lower matrix phosphoprotein (UL83) gene and DNA polymerase (UL54) gene showed reasonable sensitivity and no mismatches with clinical isolates. These three pairs were further tested with clinical samples, which indicated that the two primer sets from UL55 and UL54 were the most sensitive. Interestingly, the analytical sensitivity of the PCR was inversely correlated with the size of the PCR product. In conclusion, these two primer pairs are recommended for a standardized, highly sensitive, real-time PCR.


Mycoses ◽  
2002 ◽  
Vol 45 (S2) ◽  
pp. 26-26
Author(s):  
S. Jalal ◽  
E. Norberg ◽  
J. Tollemar ◽  
J. Loeffler ◽  
L. Klingspor

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12561
Author(s):  
Pimchanok Panpru ◽  
Arpasiri Srisrattakarn ◽  
Nuttanun Panthasri ◽  
Patcharaporn Tippayawat ◽  
Aroonwadee Chanawong ◽  
...  

Vancomycin-resistant enterococci (VRE), especially Enterococcus faecium, have been a global concern, often causing serious healthcare-associated infections. We established a rapid approach for detecting E. faecium and vancomycin-resistance genes (vanA and vanB) in clinical samples using isothermal recombinase polymerase amplification (RPA) combined with a lateral-flow (LF) strip. Specific RPA primer sets and probes for ddl (to identify the presence of E. faecium) vanA and vanB genes were designed. The RPA reaction was performed under isothermal condition at 37 °C within 20 min and read using the LF strip within a further 5 min. A total of 141 positive blood-cultures and 136 stool/rectal swab samples were tested using RPA-LF method compared to the conventional PCR method. The RPA-LF method exhibited 100% sensitivity in both blood-culture (60 E. faecium; 35 vanA type and two vanB type) and stool/rectal-swab samples (63 E. faecium and 36 vanA type) without cross-reaction (100% specificity). The lower detection limit of the RPA-LF was approximately 10 times better than that of the conventional PCR method. The RPA-LF method is an alternative rapid method with excellent sensitivity and specificity for detecting E. faecium, vanA, and vanB, and it has the potential to be used as a point-of-care device for VRE therapy and prevention.


1998 ◽  
Vol 36 (10) ◽  
pp. 2990-2995 ◽  
Author(s):  
J. Stockton ◽  
J. S. Ellis ◽  
M. Saville ◽  
J. P. Clewley ◽  
M. C. Zambon

A multiplex reverse transcription (RT)-PCR method that has been developed is capable of detecting and subtyping influenza A (H1N1 and H3N2) and B viruses as well as respiratory syncytial virus (RSV) types A and B in respiratory clinical samples taken as part of a national community-based surveillance program of influenza-like illness in England and Wales. The detection of each different pathogen depended on distinguishing five amplification products of different sizes on agarose gels following RT-PCR with multiple primer sets. The multiplex RT-PCR was tested with 65 nasopharyngeal apirates from which RSV had been isolated and 237 combined nose and throat swabs from which influenza A (H1N1 and H3N2) or B virus had been detected by virus isolation, as well as 40 respiratory samples from which other viruses including cytomegalovirus, herpes simplex virus, enteroviruses, and parainfluenza viruses had been grown. For the typing and subtyping of influenza A and B viruses and RSV types A and B, the multiplex RT-PCR gave an excellent (100%) correlation with the results of conventional typing and subtyping with specific antisera. Multiplex RT-PCR can also be used to accurately detect more than one viral template in the same reaction mixture, allowing viral coinfections to be identified with the same respiratory specimen.


2020 ◽  
Vol 26 (1-2) ◽  
pp. 73-78
Author(s):  
A Hossen ◽  
MH Rahman ◽  
MZ Ali ◽  
MA Yousuf ◽  
MZ Hassan ◽  
...  

Duck plague (DP) is the most important infectious disease of geese, ducks and free-ranging water birds. The present study was conducted to determine the prevalence of duck plague virus followed by isolation and identification. For these purposes, a total of 155 cloacal swabs samples were collected randomly from duck of different haor areas of Bangladesh including 45 (41 surveillance and 4 clinical) samples from Netrokona; 42 (40 surveillance and 2 clinical) samples from Kishoregonj; 30 samples from Brahmanbaria and 38 samples from Sunamganj. The samples were processed and pooled (1:5 ratio) for initial screening of target polymerase gene of duck plague virus by polymerase chain reaction (PCR) method. All the samples of a positive pool were then tested individually for identifying the individual positive samples. The result showed that out of 155 samples, 41 (26.45%) were found positive in which 17 were from Netrokona, where 15 (36.58%) were from surveillance samples and 2 (50%) were from clinical sample; 16 were from Kishoregonj, where 14 (35%) were from surveillance samples and 2 (100%) were from clinical sample; 2 (6.6%) were from Brahmanbaria and 5 (13.15%) were from Sunamganj. These positive samples were inoculated into 9-10 days embryonated duck eggs (EDE) through chorioallantoic membrane (CAM) route for the isolation of virus. The EDE died earlier was also chilled, and in a similar way, the CAMs were collected and again performed PCR for id entification of virus. Out of 41 PCR positive samples, 26 samples were isolated and reconfirmed by PCR. Subsequently, DPV was isolated in primary duck embryo fibroblasts cell culture and confirmed by observing cytopathic effect (CPE). Bang. J. Livs. Res. Vol. 26 (1&2), 2019: P. 73-78


2020 ◽  
pp. 54-59
Author(s):  
A. S. Molostova ◽  
N. S. Gladyshev ◽  
A. V. Svarval ◽  
R. S. Ferman ◽  
A. B. Karasyova ◽  
...  

(HP) infection was performed using invasive and non-invasive methods. The study group consisted of 95 patients with dyspepsia. HP infection was detected in 47 patients (49.4 %). The expediency of using a set of diagnostic methods for detecting HP (PCR, immunochromatographic, bacteriological and method for determining urease activity) is proved. Most often (100 %) in patients HP infection was detected in biopsies using the PCR method. Somewhat less frequently it was detected when examining biopsies with an invasive biochemical method (AMA RUT Reader) (82 %) and fecal immunochromatographic method (83 %). Despite the fact that helicobacteriosis was detected bacteriologically in a small number of patients (24 %), this method is of particular value, since it allows you to assess the sensitivity to antimicrobial drugs and probiotics, and does not give false positive results.


2011 ◽  
Vol 74 (2) ◽  
pp. 240-247 ◽  
Author(s):  
MIGUELÁNGEL PAVÓN ◽  
ISABEL GONZÁLEZ ◽  
MARÍA ROJAS ◽  
NICOLETTE PEGELS ◽  
ROSARIO MARTÍN ◽  
...  

The genus Alternaria is considered one of the most important fungal contaminants of vegetables, fruits, and cereals, producing several mycotoxins that can withstand food processing methods. Conventional methods for Alternaria identification and enumeration are laborious and time-consuming, and they might not detect toxigenic molds inactivated by food processing. In this study, a PCR method has been developed for the rapid identification of Alternaria spp. DNA in foodstuffs, based on oligonucleotide primers targeting the internal transcribed spacer (ITS) 1 and ITS2 regions of the rRNA gene. The specificity of the Alternaria-specific primer pair designed (Dir1ITSAlt–Inv1ITSAlt) was verified by PCR analysis of DNA from various Alternaria spp., and also from several fungal, bacterial, yeast, animal, and plant species. The detection limit of the method was 102 CFU/ml in viable culture, heated culture, or experimentally inoculated tomato pulp. The applicability of the method for detection of Alternaria spp. DNA in foodstuffs was assessed by testing several commercial samples. Alternaria DNA was detected in 100% of spoiled tomato samples, 8% of tomato products, and 36.4% of cereal-based infant food samples analyzed.


2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yang Zhang ◽  
Chunyang Dai ◽  
Huiyan Wang ◽  
Yong Gao ◽  
Tuantuan Li ◽  
...  

Abstract Background Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is posing a serious threat to global public health. Reverse transcriptase real-time quantitative polymerase chain reaction (qRT-PCR) is widely used as the gold standard for clinical detection of SARS-CoV-2. Due to technical limitations, the reported positive rates of qRT-PCR assay of throat swab samples vary from 30 to 60%. Therefore, the evaluation of alternative strategies to overcome the limitations of qRT-PCR is required. A previous study reported that one-step nested (OSN)-qRT-PCR revealed better suitability for detecting SARS-CoV-2. However, information on the analytical performance of OSN-qRT-PCR is insufficient. Method In this study, we aimed to analyze OSN-qRT-PCR by comparing it with droplet digital PCR (ddPCR) and qRT-PCR by using a dilution series of SARS-CoV-2 pseudoviral RNA and a quality assessment panel. The clinical performance of OSN-qRT-PCR was also validated and compared with ddPCR and qRT-PCR using specimens from COVID-19 patients. Result The limit of detection (copies/ml) of qRT-PCR, ddPCR, and OSN-qRT-PCR were 520.1 (95% CI: 363.23–1145.69) for ORF1ab and 528.1 (95% CI: 347.7–1248.7) for N, 401.8 (95% CI: 284.8–938.3) for ORF1ab and 336.8 (95% CI: 244.6–792.5) for N, and 194.74 (95% CI: 139.7–430.9) for ORF1ab and 189.1 (95% CI: 130.9–433.9) for N, respectively. Of the 34 clinical samples from COVID-19 patients, the positive rates of OSN-qRT-PCR, ddPCR, and qRT-PCR were 82.35% (28/34), 67.65% (23/34), and 58.82% (20/34), respectively. Conclusion In conclusion, the highly sensitive and specific OSN-qRT-PCR assay is superior to ddPCR and qRT-PCR assays, showing great potential as a technique for detection of SARS-CoV-2 in patients with low viral loads.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chukwunonso Onyilagha ◽  
Henna Mistry ◽  
Peter Marszal ◽  
Mathieu Pinette ◽  
Darwyn Kobasa ◽  
...  

AbstractThe coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), calls for prompt and accurate diagnosis and rapid turnaround time for test results to limit transmission. Here, we evaluated two independent molecular assays, the Biomeme SARS-CoV-2 test, and the Precision Biomonitoring TripleLock SARS-CoV-2 test on a field-deployable point-of-care real-time PCR instrument, Franklin three9, in combination with Biomeme M1 Sample Prep Cartridge Kit for RNA 2.0 (M1) manual extraction system for rapid, specific, and sensitive detection of SARS-COV-2 in cell culture, human, and animal clinical samples. The Biomeme SARS-CoV-2 assay, which simultaneously detects two viral targets, the orf1ab and S genes, and the Precision Biomonitoring TripleLock SARS-CoV-2 assay that targets the 5′ untranslated region (5′ UTR) and the envelope (E) gene of SARS-CoV-2 were highly sensitive and detected as low as 15 SARS-CoV-2 genome copies per reaction. In addition, the two assays were specific and showed no cross-reactivity with Middle Eastern respiratory syndrome coronavirus (MERS-CoV), infectious bronchitis virus (IBV), porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis (TGE) virus, and other common human respiratory viruses and bacterial pathogens. Also, both assays were highly reproducible across different operators and instruments. When used to test animal samples, both assays equally detected SARS-CoV-2 genetic materials in the swabs from SARS-CoV-2-infected hamsters. The M1 lysis buffer completely inactivated SARS-CoV-2 within 10 min at room temperature enabling safe handling of clinical samples. Collectively, these results show that the Biomeme and Precision Biomonitoring TripleLock SARS-CoV-2 mobile testing platforms could reliably and promptly detect SARS-CoV-2 in both human and animal clinical samples in approximately an hour and can be used in remote areas or health care settings not traditionally serviced by a microbiology laboratory.


2016 ◽  
Vol 2 (5) ◽  
pp. e1600300 ◽  
Author(s):  
Ki Soo Park ◽  
Chen-Han Huang ◽  
Kyungheon Lee ◽  
Yeong-Eun Yoo ◽  
Cesar M. Castro ◽  
...  

Health care–associated infections (HAIs) and drug-resistant pathogens have become a major health care issue with millions of reported cases every year. Advanced diagnostics would allow clinicians to more quickly determine the most effective treatment, reduce the nonspecific use of broad-spectrum antimicrobials, and facilitate enrollment in new antibiotic treatments. We present a new integrated system, polarization anisotropy diagnostics (PAD), for rapid detection of HAI pathogens. The PAD uses changes of fluorescence anisotropy when detection probes recognize target bacterial nucleic acids. The technology is inherently robust against environmental noise and economically scalable for parallel measurements. The assay is fast (2 hours) and performed on-site in a single-tube format. When applied to clinical samples obtained from interventional procedures, the PAD determined the overall bacterial burden, differentiated HAI bacterial species, and identified drug resistance and virulence status. The PAD system holds promise as a powerful tool for near-patient, rapid HAI testing.


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