Verification of clinical samples, positive in AMPLICOR Neisseria gonorrhoeae polymerase chain reaction, by 16S rRNA and gyrA compared with culture

2005 ◽  
Vol 16 (6) ◽  
pp. 415-419 ◽  
Author(s):  
Åsa Airell ◽  
Emma Lindbäck ◽  
Ferda Ataker ◽  
Kirsti Jalakas Pörnull ◽  
Bengt Wretlind
Keyword(s):  
Polymerase Chain Reaction ◽  
16S Rrna ◽  
Neisseria Gonorrhoeae ◽  
False Negative ◽  
Clinical Samples ◽  
Rrna Gene ◽  
Chain Reaction ◽  
Gyra Gene ◽  
Two Samples ◽  
Polymerase Chain

We compared 956 samples for AMPLICOR Neisseria gonorrhoeae polymerase chain reaction (PCR) (Roche) with species verification using the 16S rRNA gene to verification using gyrA gene. Control was the culture method. The gyrA verification uses pyrosequencing of the quinolone resistance-determining region of gyrA. Of 52 samples with optical density ≥0.2 in PCR, 27 were negative in culture, two samples from pharynx were false negative in culture and four samples from pharynx were false positives in verification with 16S rRNA. Twenty-five samples showed growth of gonococci, 18 of the corresponding PCR samples were verified by both methods; three urine samples were positive only in gyrA ; and one pharynx specimen was positive only in 16S rRNA. Three samples were lost. We conclude that AMPLICOR N. gonorrhoeae PCR with verification in gyrA gene can be considered as a diagnostic tool in populations with low prevalence of gonorrhoea and that pharynx specimens should not be analysed by PCR.

scholarly journals UTILITY OF ANTIGEN DETECTION TEST AND POLYMERASE CHAIN REACTION IN THE DIFFERENTIATION OF TUBERCULOUS AND NON-TUBERCULOUS MYCOBACTERIA

2017 ◽  
Vol 10 (6) ◽  
pp. 289
Author(s):  
Yogita Singh ◽  
Raji Vasanth ◽  
Shrikala Baliga ◽  
Dhanashree B
Keyword(s):  
Polymerase Chain Reaction ◽  
False Negative ◽  
Diagnostic Methods ◽  
Clinical Samples ◽  
Chain Reaction ◽  
College Hospital ◽  
Medical College ◽  
Negative Results ◽  
Polymerase Chain ◽  
Mycobacterium Spp

Objectives: Cultivation and identification of mycobacteria to species level remains difficult and time-consuming. Hence, easy and rapid diagnostic methods are necessary for the differentiation of Mycobacterium tuberculosis (MTB) from non-tuberculous mycobacteria (NTM). The present study aims to detect and differentiate MTB from NTM isolated from clinical samples by immunochromatographic test (ICT) and polymerase chain reaction (PCR). Methods: Over a period of 1 year, clinical samples (n=496) received from suspected cases of TB, at the Department of Microbiology, Kasturba Medical College Hospital, Mangalore were cultured to isolate Mycobacterium spp. Identification of all the isolates was done by conventional biochemical technique, ICT, and PCR. Results: Among the 496 samples processed, 49 (9.87%) were acid-fast bacilli smear positive and 59 (11.89%) samples showed the growth of Mycobacterium spp. Among these, 10 were rapid growers, 49 were slow-growing mycobacteria, out of which 30 were MTB as identified by conventional biochemical reaction. Out of 59 Mycobacterial isolates subjected to ICT for the detection of MPT 64 antigen, only 28 were identified as MTB. However, all the 30 isolates were correctly identified as MTB by PCR. Conclusion: Hence, PCR is essential for rapid differentiation of non-tuberculous Mycobacterium from MTB. False negative results seen with immunochromatographic MPT 64 antigen assay could be due to mutations within the mpt64 gene. Further studies are necessary to characterize these PCR-positive and immunochromatographic assay negative MTB isolates.

scholarly journals Comparison of polymerase chain reaction and microscopy for the detection of Fasciola spp. in the fecal matter of domestic bovines in Kalasin Province, Thailand

2021 ◽  
pp. 2878-2882
Author(s):  
Sirikanda Thanasuwan ◽  
Anupong Tankrathok
Keyword(s):  
Polymerase Chain Reaction ◽  
False Negative ◽  
Economic Losses ◽  
Rrna Gene ◽  
28S Rrna ◽  
Chain Reaction ◽  
Fecal Matter ◽  
Specificity And Sensitivity ◽  
Polymerase Chain ◽  
Fasciola Spp

Background and Aim: Fasciola spp. are important foodborne trematodes and waterborne zoonotic parasites that cause health problems and economic losses worldwide, including in Thailand. Fasciola spp. are usually detected by sedimentation or the formalin-ethyl acetate concentration technique (FECT) under microscopy, which is less specific and sensitive. Accurate detection is important to detect real incidence for protection against and elimination of fasciolosis in the area. This study aimed to determine the distribution of Fasciola spp. and compare the specificity and sensitivity of FECT under microscopy to that of polymerase chain reaction (PCR) in cattle feces. Materials and Methods: The study was conducted in Kalasin Province, Thailand. Feces of 46 cattle were investigated for infection with Fasciola spp. To detect infection, FECT under microscopy and PCR amplification of the 28S rRNA gene of Fasciola spp. were used to identify egg parasites. Results: Feces of 16 of 46 (34.78%) cattle were positive for Fasciola spp. using FECT under microscopy, whereas PCR showed that 67.39% (31 of 46) were positive for Fasciola spp. False-negative results were as high as 32.61% when diagnosed under microscopy. Conclusion: This study confirmed the infection of cattle with Fasciola spp. in Kalasin Province, indicating that PCR demonstrated higher sensitivity and specificity when diagnosing infection. FECT under microscopy can still be used as a primary and traditional method for diagnosis. However, relapse cases of Fasciola spp. and Paramphistomum spp. should be diagnosed by microscopy combined with PCR. This is the first report on the molecular distribution of fecal samples in cattle in Kalasin Province.

scholarly journals The Use of a Mimic to Detect Polymerase Chain Reaction– Inhibitory Factors in Feces Examined for the Presence of Lawsonia Intracellularis

2003 ◽  
Vol 15 (3) ◽  
pp. 268-273 ◽  
Author(s):  
Magdalena Jacobson ◽  
Stina Englund ◽  
András Ballagi-Pordány
Keyword(s):  
Polymerase Chain Reaction ◽  
False Negative ◽  
Clinical Samples ◽  
Lawsonia Intracellularis ◽  
Chain Reaction ◽  
Fecal Samples ◽  
Wild Boars ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain

Lawsonia intracellularis is an intracellular organism that causes proliferative enteritis in pigs. This bacterium is difficult to culture, and antemortem demonstration of the microbe is therefore often performed on fecal samples by polymerase chain reaction (PCR). Polymerase chain reaction is sensitive and specific, but inhibitory factors in feces might cause false-negative results. This article describes the construction and use of an internal standard, a mimic. The mimic is amplified by the same primers as those used for L. intracellularis DNA and thus could indicate false-negative results in clinical samples. The amplicon was clearly visible when as few as 10 mimic molecules were added per amplification reaction and when no inhibitors were present. When fecal samples were spiked with the mimic, the detection limit was 102 molecules per PCR. Sixty clinical samples, 20 from wild boars, 20 from growing pigs with diarrhea, and 20 from pigs without diarrhea, were prepared by a boiling procedure and subjected to PCR together with 103 mimic molecules. Nine samples were positive, of which 7 originated from pigs with diarrhea and 2 from pigs without diarrhea. In 14 samples from wild boars, in 8 samples from pigs without diarrhea, and in 3 samples from pigs with diarrhea, neither the mimic nor the target DNA was visible. This indicated the presence of inhibitors in these samples. It is concluded that the mimic can be used as an internal control in the diagnosis of L. intracellularis to indicate inhibition of PCR.

scholarly journals Evaluasi Deteksi Berbasis PCR untuk Bakteri Bifidobacterium longum dalam Sampel Feses Bayi dari Kota Manado

2020 ◽  
Vol 20 (1) ◽  
pp. 18
Author(s):  
Beivy Jonathan Kolondam
Keyword(s):  
Polymerase Chain Reaction ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Detection Method ◽  
Bifidobacterium Longum ◽  
Local Alignment ◽  
Rrna Gene ◽  
Chain Reaction ◽  
Search Tool ◽  
Polymerase Chain

Bifidobakteria merupakan mikroflora yang umum hidup dalam usus manusia sejak bayi. Peran Bifidobacterium longum yang positif sebagai salah satu bakteri yang menunjang kesehatan inangnya membuat bakteri ini menjadi objek studi yang menarik. Salah satu instrumen dalam penelitian adalah adalah metode deteksi bakteri B. longum yang berbasis PCR (Polymerase Chain Reaction) gen 16S rRNA. Dengan mempertimbangkan bahwa perancangan primer untuk deteksi ini sudah lebih dari 20 tahun, penelitian ini bertujuan mengevaluasi hasil deteksi melalui PCR terhadap B. longum dalam feses bayi. Akurasi hasil dilihat melalui sekuensing terhadap hasil PCR sampel yang terdeteksi positif. Dua sampel feses bayi di Manado yang diperiksa menunjukkan hasil positif dan produk PCR tersebut dilakukan sekuensing. Panjang DNA yang nyata dari hasil deteksi ini yaitu 829 bp dan bukan 831 bp. Sekuens DNA kedua sampel ini identik satu sama lain. Hasil BLAST (Basic Local Alignment Search Tool) mengonfirmasi kesamaan 100% (identik) dari kedua specimen dari Kota Manado dengan sekuens gen 16S rRNA specimen bakteri B. longum yang telah ada dalam GenBank.Kata-kata kunci: Bifidobacterium longum, Polymerase Chain Reaction, deteksi, feses, bayi. Evaluation of PCR-Based Detection for Bifidobacterium longum in Infant Fecal Samples from Manado City ABSTRACTBifidobacteria are common members of the gut microflora of humans since infant. The Bifidobacterium longum has positive roles and one of supportive bacteria to the host, which made interesting as a study object. One instrument in studying this bacterial species is the detection method based on PCR of 16S rRNA gene. In consideration of the design of primers for this detection method is already more than 20 years, this research aimed to evaluate the PCR-based detection of B. longum in infant feces. The accuracy of the method was evaluated from sequencing of DNA fragment from positive results. Two fecal samples in Manado City shown positive result were sent for sequencing. The actual length of DNA amplified by PCR was 829 bp, not 831 bp. The DNA sequence of both samples were identical to each other. The BLAST (Basic Local Alignment Search Tool) result confirmed the similarity of both samples from Manado with 16S rRNA gene sequence of B. longum specimens in GenBank.Keywords: Bifidobacterium longum, Polymerase Chain Reaction, detection, feces, infant.

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