scholarly journals Critical analysis: use of polymerase chain reaction to diagnose leprosy

2016 ◽  
Vol 52 (1) ◽  
pp. 163-169 ◽  
Author(s):  
Flaviane Granero Maltempe ◽  
Vanessa Pietrowski Baldin ◽  
Mariana Aparecida Lopes ◽  
Vera Lúcia Dias Siqueira ◽  
Regiane Bertin de Lima Scodro ◽  
...  

ABSTRACT Leprosy is a neglected tropical disease and an important public health problem, especially in developing countries. It is a chronic infectious disease that is caused by Mycobacterium leprae, which has a predilection for the skin and peripheral nerves. Although it has low sensitivity, slit-skin smear (SSS) remains the conventional auxiliary laboratory technique for the clinical diagnosis of leprosy. Polymerase chain reaction (PCR) is a molecular biology technique that holds promise as a simple and sensitive diagnostic tool. In the present study, the performance of two PCR methods, using different targets, PCR-LP and PCR-P, were compared with SSS with regard to leprosy diagnosis in a reference laboratory. M. leprae DNA was extracted from 106 lymph samples of 40 patients who had clinical suspicion of leprosy. The samples were subjected to both PCR techniques and SSS. Amplification of the human b-globin gene was used as PCR inhibitor control. The specificity of both PCR techniques was 100%, and sensitivity was 0.007 and 0.015 µg/ml for PCR-LP and PCR-P, respectively. No significant difference was found between either the PCR-LP or PCR-P results and SSS results (p > 0.05). Although PCR is not yet a replacement for SSS in the diagnosis of leprosy, this technique may be used as an efficient auxiliary tool for early detection of the disease, especially in endemic regions. This strategy may also be useful in cases in which SSS results are negative (e.g., in paucibacillary patients) and cases in which skin biopsy cannot be performed.

2012 ◽  
Vol 3 (1) ◽  
pp. 13
Author(s):  
Aline T.A. Chagas ◽  
Michelle D. Oliveira ◽  
Jose M.S. Mezencio ◽  
Eduardo A.M. Silva ◽  
Leandro L. Oliveira ◽  
...  

The <em>Dengue virus</em> is the main arbovirus that affects man in terms of morbidity and mortality. The detection of the virus is very important for epidemiological surveillance, so here we propose to standardize and compare the immunodot blot (IDB) and multiplex reverse transcriptase-polymerase chain reaction (M-RT-PCR) techniques to detect and characterize the dengue virus (DENV) serotypes in samples of <em>Aedes aegypti</em> larvae. Thus, the IDB and M-RT-PCR techniques were standardized using macerated samples of larvae collected in nature. The use of monoclonal antibodies in IDB has not shown great results, but DENV detection through this method was possible using polyclonal antibodies. The distinction of serotypes 1, 2 and 3 was carried out by M-RT-PCR.


2013 ◽  
Vol 2 (1) ◽  
pp. 12-16
Author(s):  
A Shrestha ◽  
N Adhikari ◽  
Y Shah ◽  
P Poudel ◽  
B Acharya ◽  
...  

Introduction: Chlamydia trachomatis is a sexually transmitted organism and causes important public health problem in the sexually active age group. Limited studies are found regarding the prevalence of C. trachomatis in Nepal. Moreover, currently there are no any study in Nepal reporting the association of chlamydia and HIV infection. This study attempts to determine the burden of chlamydia on HIV positive patients. Materials and Methods: A total of 117 HIV positive patients visiting a HIV clinic in Kathmandu, were screened for chlamydia infection. For this, urine samples were collected and analyzed using the Polymerase Chain Reaction Technique (PCR). Results: C. trachomatis was detected in 4.2% of the total 117 HIV patients. Out of positive cases 60% were males and 40% were females. However, chlamydia was found more prevalent among females (6.8%) than males (3.4%). Eighty percent of positive cases were asymptomatic. Conclusions: Although, the prevalence of chlamydia infection was found less HIV patients, most of those cases were asymptomatic. Therefore, routine checkup is recommended for all suspected cases for timely management of the disease. DOI: http://doi.dx.org/10.3126/ijim.v2i1.8003 Int J Infect Microbiol 2013;2(1):12-16


1995 ◽  
Vol 41 (9) ◽  
pp. 816-825 ◽  
Author(s):  
R. J. Watson ◽  
C. Haitas-Crockett ◽  
T. Martin ◽  
R. Heys

A genetically marked Rhizobium meliloti strain, R692, was prepared by insertion of a 1.7-kb DNA segment from Tn903 between the nifHDK and fixABC genes in the nod megaplasmid. This DNA was used as a marker, detectable by polymerase chain reaction (PCR), for the specific identification of bacteria in soil samples and alfalfa nodules. This detection technique was tested by applying different titres of the marked strain to field plots seeded with alfalfa. Samples of soil and nodules were assayed for the presence of the marker DNA fragment by PCR using primers specific to the marker sequence. The experiments revealed that the bacteria could be detected directly in soil containing about 103–104 bacteria/g, but greater sensitivity was prevented by potent PCR inhibitors present in the samples. The titre of the bacteria in the soil decreased rapidly after inoculation, dropping about 10-fold per week. Tests of vertical location of the bacteria in soil cores showed that the bacteria were initially dispersed to a depth of 18 cm, and subsequently retained viability in the top 2–8 cm. As few as 10 marked R. meliloti per gram of soil resulted in its establishment at detectable levels in nodules. Application of about 104–105 bacteria/g soil was sufficient to give the maximum number of nodules per plant and resulted in 70–90% occupancy by the marked strain. Limited movement of the inoculant was detected by analysis of nodules from plants adjacent to the sites where the bacteria were applied, probably by movement in water. The experiments demonstrated the advantages of PCR for the monitoring of marked microorganisms in the environment.Key words: genetically engineered microorganism, PCR inhibitor, nitrogen fixation, nif and fix genes, genetic marker.


Blood ◽  
1991 ◽  
Vol 78 (9) ◽  
pp. 2433-2437 ◽  
Author(s):  
SZ Huang ◽  
GP Rodgers ◽  
FY Zeng ◽  
YT Zeng ◽  
AN Schechter

Abstract We have developed a technique to diagnose the alpha- and beta- thalassemia (thal) syndromes using the polymerase chain reaction to amplify cDNA copies of circulating erythroid cell messenger RNA (mRNA) so as to quantitate the relative amounts of alpha-, beta-, and gamma- globin mRNA contained therein. Quantitation, performed by scintillation counting of 32P-dCTP incorporated into specific globin cDNA bands, showed ratios of alpha/beta-globin mRNA greater than 10-fold and greater than fivefold increased in patients with beta 0- and beta (+)- thal, respectively, as well as a relative increase in gamma-globin mRNA levels. Conversely, patients with alpha-thalassemia showed a decreased ratio of alpha/beta-globin mRNA proportional to the number of alpha- globin genes deleted. This methodology of ascertaining ratios of globin mRNA species provides a new, simplified approach toward the diagnosis of thalassemia syndromes, and may be of value in other studies of globin gene expression at the transcription level.


1993 ◽  
Vol 79 (2) ◽  
pp. 133-136 ◽  
Author(s):  
Guseppe Pellegris ◽  
Claudia Lombardo ◽  
Annelisa Cantoni ◽  
Liliana Devizzi ◽  
Monica Balzarotti

Background A number of reports have studied associations between Hodgkin's disease and HLA. Some of them established correlation between several antigens and Hodgkin's disease, and others found no correlations. Methods The HLA DP locus was determined by the polymerase chain reaction method in 31 Hodgkin's disease patients and 58 healthy controls. Results No significant difference between patients and controls was noted. Conclusions Further investigations are needed to confirm the hypothesis of a possible role of the HLA complex as one of the factors involved in Hodgkin's disease.


Blood ◽  
1994 ◽  
Vol 83 (5) ◽  
pp. 1412-1419 ◽  
Author(s):  
T Furukawa ◽  
G Zitnik ◽  
K Leppig ◽  
T Papayannopoulou ◽  
G Stamatoyannopoulos

Abstract We developed a method detecting globin gene expression in single cells using reverse transcription polymerase chain reaction. epsilon and gamma globin cDNAs are coamplified by an epsilon gamma primer set whereas gamma and beta globin cDNAs are coamplified by a gamma beta primer set and the individual globin cDNAs are distinguished by restriction enzyme digestion. Analysis of RNA preparations from human fetal liver, neonatal red blood cells (RBCs), or adult RBCs showed the expected mRNA species for each stage of human development. Analysis of single cells from a human erythroleukemia line coexpressing gamma and beta globin chains showed heterogeneity in gamma and beta mRNA contents. The method was subsequently used to test whether only one or more than one globin genes are expressed in cells that contain a single human beta globin locus. We found that about 50% of single cells from MEL x fetal erythroid cell hybrids containing a single human beta globin locus coexpressed gamma and beta globin mRNA. This finding is best explained by assuming that both gamma and beta genes are simultaneously transcribed from the same beta globin locus implying that the LCR can simultaneously interact with more than one globin gene promoter.


Author(s):  
Mami Taniuchi ◽  
Kamrul Islam ◽  
Md Abu Sayeed ◽  
James A Platts-Mills ◽  
Md Taufiqul Islam ◽  
...  

Abstract Background Diarrhea remains a major public health problem and characterization of its etiology is needed to prioritize interventions. However, most data are from single-site studies of children. We tested samples from participants of any age from 11 geographically diverse hospitals in Bangladesh to describe pathogen-specific burdens of diarrhea. Methods We utilized 2 existing diarrhea surveillance systems: a Nationwide network at 10 sentinel hospitals and at the icddr,b hospital. We tested stools from enrolled participants and nondiarrheal controls for enteropathogens using quantitative polymerase chain reaction and calculated pathogen-specific attributable fractions (AFs) of diarrhea. Results We analyzed 5516 patients with diarrhea and 735 controls. Overall, rotavirus had the highest attributable burden of diarrhea (Nationwide AF, 17.7%; 95% confidence interval [CI], 14.3–20.9%; icddr,b AF, 39.9%; 38.0–41.8%), followed by adenovirus 40/41 (Nationwide AF, 17.9%; 95% CI: 13.9–21.9%; icddr,b AF, 16.6%; 95% CI, 14.4–19.4%) and Vibrio cholerae (Nationwide AF, 10.2%; 95% CI, 9.1–11.3%; icddr,b AF, 13.3%; 95% CI: 11.9–15.1%). Rotavirus was the leading pathogen in children &lt;5 years and was consistent across the sites (coefficient of variation = 56.3%). Adenovirus 40/41 was the second leading pathogen in both children and adults. Vibrio cholerae was the leading pathogen in individuals &gt;5 years old, but was more geographically variable (coefficient of variation = 71.5%). Other attributable pathogens included astrovirus, norovirus, Shigella, Salmonella, ETEC, sapovirus, and typical EPEC. Conclusions Rotavirus, adenovirus 40/41, and V. cholerae were the leading etiologies of infectious diarrhea requiring hospitalization in Bangladesh. Other pathogens were important in certain age groups or sites.


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