Mycobacterial and Fungal Diagnostics

2012 ◽  
pp. 41-52
Author(s):  
Matthew J. Binnicker ◽  
Glenn D. Roberts ◽  
Nancy L. Wengenack
Keyword(s):  
Polymerase Chain Reaction ◽  
Mycobacterium Tuberculosis ◽  
Dna Sequencing ◽  
Molecular Identification ◽  
Diagnostic Methods ◽  
Direct Examination ◽  
Chain Reaction ◽  
Fungal Organisms ◽  
Polymerase Chain

This chapter reviews diagnostic methods and tests for identifying mycobacterial and fungal organisms. Diagnostic methods include direct examination, staining, culture, molecular identification, DNA sequencing, chromatography, polymerase chain reaction, and immunodiagnostics. Organisms reviewed include Mycobacterium tuberculosis, M kansasii, M marinum, M leprae, M avium, and other mycobacteria; Aspergillus spp; Histoplasma spp; Coccidioides spp; Blastomyces spp; Candida spp; Fusarium spp; Trichophyton spp; and other fungi.

scholarly journals Molecular Identification of Begomovirus Infecting Angled Luffa

2020 ◽  
Vol 24 (2) ◽  
pp. 147
Author(s):  
Alvina Clara Giovanni ◽  
Sedyo Hartono ◽  
Sri Sulandari ◽  
Susamto Somowiyarjo
Keyword(s):  
Polymerase Chain Reaction ◽  
Dna Sequencing ◽  
Molecular Identification ◽  
Leaf Shape ◽  
Mosaic Symptom ◽  
Chain Reaction ◽  
Central Java ◽  
Total Dna ◽  
Polymerase Chain ◽  
Luffa Acutangula

Begomovirus was reported as one of the most aggressive and destructive viruses on several commercial crops, including cucurbits in Indonesia. Plants that infected with Begomovirus show the mosaic symptom on the leaves, change in leaf shape, stunts, change in color and shape of fruit. It was recently observed in cultivated angled luffa [Luffa acutangula (L.) Roxb] around Yogyakarta and Central Java. The aim of this research was to identify the virus by using Polymerase chain reaction (PCR). The result of Begomovirus amplification from the total DNA samples amplification using primer Krusty-Homer showed that DNA of Begomovirus from angled luffa was amplified at ~580bp. The DNA sequencing of angled luffa’s leaf isolate GD1 had 97.8% homology with SCLV-China isolate MC1. However, amplification of DNA seed samples using the same primer showed negative result. It was concluded that Begomovirus was not a seed borne virus. This is the first molecular report on the occurence of Begomovirus in angled luffa in Yogyakarta.

scholarly journals Novel Mutations Detected from Drug Resistant Mycobacterium Tuberculosis Isolated from North East of Thailand

2021 ◽  
Author(s):  
Ei Phoo Thwe ◽  
Wises Namwat ◽  
Porntip Pinlaor ◽  
Kulrattana Rueangsak ◽  
Arunnee Sangka
Keyword(s):  
Polymerase Chain Reaction ◽  
Mycobacterium Tuberculosis ◽  
Dna Sequencing ◽  
Drug Resistant ◽  
Novel Mutations ◽  
Chain Reaction ◽  
Drug Resistant Tuberculosis ◽  
Resistant Tuberculosis ◽  
Polymerase Chain ◽  
Northeastern Thailand

Abstract The emergence of drug-resistant tuberculosis is a major global public health threat. Thailand is one of the top 14 countries with high tuberculosis, tuberculosis co-infected with Human Immunodeficiency Virus (HIV) and multi-drug resistant tuberculosis rates. Immediate detection of drug-resistant tuberculosis is necessary to reduce mortality and morbidity by effectively providing treatment to ameliorate the formation of resistant strains. Limited data exist of mutation profiles in Northeastern Thailand. Here, 65 drug-resistant Mycobacterium tuberculosis isolates were used to detect mutations by polymerase chain reaction (PCR) and DNA sequencing. In the katG gene, mutations occurred in 47(79.7%) among 59 isoniazid resistant samples. For rpoB gene, 31 (96.9%) were observed as mutations in 32 rifampicin resistant isolates. Of 47 katG mutation samples, 45 (95.7%) had mutations in katG 315 codon and 2 (4.3%) showed novel mutations at katG 365 with amino acid substitution of CCG-CGG (Pro-Arg). Moreover, 18 (58.1%) mutations at rpoB 531, 11 (35.5%) mutations at rpoB 516, 10 (32.3%) mutations at rpoB 526 and 1 (3.2%) mutation at rpoB 533 were found between 31 rifampicin resistant samples. Common and novel mutations of the rpoB and katG genes in Northeastern Thailand were generated. DNA sequencing showed high accuracy, while conventional polymerase chain reaction could be applied as an initial marker for screening rifampicin and isoniazid drug-resistant Mycobacterium tuberculosis in Northeastern Thailand. Mutations reported here should be considered when developing new molecular diagnostic methods for implementation in Northeastern Thailand.

Comparison of Droplet Digital Polymerase Chain Reaction (ddPCR) and Real-Time Quantitative Polymerase Chain Reaction (qPCR) in Detecting Neonatal Invasive Fungal Infections

2021 ◽  
Vol 11 (3) ◽  
pp. 373-379
Author(s):  
Huitao Li ◽  
Xueyu Chen ◽  
Xiaomei Qiu ◽  
Weimin Huang ◽  
Chuanzhong Yang
Keyword(s):  
Polymerase Chain Reaction ◽  
Limit Of Detection ◽  
Quantitative Polymerase Chain Reaction ◽  
Diagnostic Methods ◽  
Chain Reaction ◽  
Fungal Isolation ◽  
Blood Samples ◽  
Fungal Strains ◽  
Polymerase Chain ◽  
Digital Polymerase Chain Reaction

Invasive fungal infection (IFI) is the leading cause of death in neonatal patients, yet the diagnosis of IFI remains a major challenge. At present, most IFI laboratory diagnostic methods are based on classical, but limited, methods such as fungal isolation and culture and histopathological examination. Recently, quantitative polymerase chain reaction (qPCR) and droplet digital polymerase chain reaction (ddPCR) technology have been adopted to quantify nucleic-acid identification. In this study, we established qPCR and ddPCR assays for IFI diagnosis and quantification. qPCR and ddPCR were carried out using identical primers and probe for the amplification of 18S rRNA. Assay results for three fungal strains were positive, whereas ten non-fungal strains had negative results, indicating 100% specificity for both ddPCR and qPCR methods. Genomic DNA of Candida albicans was tested after a serial dilution to compare the sensitivity of the two PCR methods. The limit of detection of ddPCR was 3.2 copies/L, which was a ten-fold increase compared with that of the qPCR method (32 copies/L). Blood samples from 127 patients with high-risk factors and clinical symptoms for IFI were collected from a NICU in Shenzhen, China, and analyzed using qPCR and ddPCR. Thirty-four blood samples from neonates had a proven or probable diagnosis of IFI, and 25 of these were positive by qPCR, whereas 30 were positive by ddPCR. Among the 93 blood samples from neonates who had a possible IFI or no IFI, 24 were positive using qPCR, and 7 were positive using ddPCR. In conclusion, ddPCR is a rapid and accurate pan-fungal detection method and provides a promising prospect for IFI clinical screening.

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 Comparative Study of Immune-Diagnostic Tools with Polymerase Chain Reaction in Sub-Clinical Leishmaniasis Isolates

2011 ◽  
Vol 12 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Nazar M Abdalla
Keyword(s):  
Polymerase Chain Reaction ◽  
Skin Test ◽  
Diagnostic Methods ◽  
Diagnostic Tools ◽  
Enzyme Linked Immunosorbent Assay ◽  
Clinical Form ◽  
Chain Reaction ◽  
Leishmanin Skin Test ◽  
Wide Range ◽  
Polymerase Chain

Objective: This study aimed to identify cases of leishmaniasis in the Nuba Mountain area, which is situated in a unique geographical site located in the centre of Sudanese leishmania belt. Wide range of investigations are available for detection of leishmania cases, but still the most reliable and easy test used as screening and epidemiological tool in field studies needs to be evaluated. The most commonly used conventional diagnostic methods direct microscopy and culture have some drawbacks in diagnosing subclinical cases of leishmaniasis. Materials and methods: In this study, comparative properties of various immune-diagnostic tools with Polymerase Chain Reaction used in sub-clinical leishmaniasis isolates were explored. The immune-diagnostic tools involved in this study include- Leishmanin Skin Test (LST), Enzyme Linked Immunosorbent Assay (ELISA) and Direct Agglutination Test (DAT). The study was conducted in the Green Valley village (Rashad Province, South Kordofan State) with a population of 332. Most of the villagers presented with sub-clinical form of leishmaniasis with minor symptoms and signs without the features found in clinical form of visceral leishmaniasis such as fever, diarrhoea, epistaxis, enlarged lymph nodes, spleen and liver. In this study we collected demographic, clinical and epidemiological data using special questionnaire. Leishmanin skin test (LST), ELISA, DAT and PCR for parasite DNA detection were used. Result: The final positive cases detected by PCR were 32 out of 332 belong to L. donovani species. The final positive cases detected by LST were 51.2% of the total population under study, while 11 out of the 37 tested samples were positive by ELISA. All of the 332 villagers showed negative readings by DAT with exception of three individuals who were positive with very high titers. Conclusion: DNA etxtraction and amplification with primers can be a good screening tool in subclinical leishmaniasis isolates. Keyword: Sub-clinical; Leishmaniasis; Leishmanin Skin Test; ELISA; DAT; PCR. DOI: 10.3329/jom.v12i1.5422J Medicine 2011; 12 : 34-39

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