scholarly journals Low sensitivity of polymerase chain reaction for diagnosis of tuberculous meningitis in southeastern Brazil

2001 ◽  
Vol 34 (4) ◽  
pp. 389-393 ◽  
Author(s):  
Vânia Maria Sabadoto Brienze ◽  
Ângela Pedroso Tonon ◽  
Fabrício José Tarelho Pereira ◽  
Elisabete Liso ◽  
Waldir Antônio Tognola ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Cerebrospinal Fluid ◽  
Tuberculous Meningitis ◽  
Nested Pcr ◽  
Southeastern Brazil ◽  
Chain Reaction ◽  
Microbiological Methods ◽  
Polymerase Chain ◽  
Low Sensitivity ◽  
Antituberculosis Chemotherapy

Two polymerase chain reaction (PCR) protocols showed low sensitivity (36% and 53% for TB AMPLICOR and MPB64 nested PCR, respectively), when compared with classic microbiological methods (73% and 54% for Ziehl-Neelsen staining and culture, respectively), in the diagnosis of tuberculous meningitis in 91 patients in southeastern Brazil. Only three PCR-positive, microbiologically negative patients were found. Analysis of sequential cerebrospinal fluid samples by nested PCR detected Mycobacterium tuberculosis DNA up to 29 days after the introduction of antituberculosis chemotherapy.

Rapid diagnosis of tuberculous meningitis by polymerase chain reaction assay of cerebrospinal fluid

1995 ◽  
Vol 242 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Juei-Jueng Lin ◽  
Horng-Jyh Harn ◽  
Yaw-Don Hsu ◽  
Wen-Long Tsao ◽  
Herng-Sheng Lee ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Cerebrospinal Fluid ◽  
Tuberculous Meningitis ◽  
Polymerase Chain Reaction Assay ◽  
Rapid Diagnosis ◽  
Chain Reaction ◽  
Polymerase Chain

Validation of Mycobacterium tuberculosis real-time polymerase chain reaction for diagnosis of tuberculous meningitis using cerebrospinal fluid samples: a pilot study

2019 ◽  
Vol 57 (4) ◽  
pp. 556-564 ◽  
Author(s):  
Sérgio M. de Almeida ◽  
Conrado M. Borges ◽  
Lucas B. Santana ◽  
Gilberto Golin ◽  
Lísia Correa ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Cerebrospinal Fluid ◽  
Mycobacterium Tuberculosis ◽  
Real Time ◽  
Tuberculous Meningitis ◽  
Predictive Value ◽  
Molecular Diagnostic ◽  
Diagnostic Tools ◽  
Chain Reaction ◽  
Polymerase Chain

Abstract Background Timely diagnosis of tuberculous meningitis (TBM) remains challenging. Molecular diagnostic tools are necessary, particularly in low- and middle-income countries. There is no approved commercial polymerase chain reaction (PCR) assay that can be used to detect Mycobacterium tuberculosis in non-respiratory samples, such as the cerebrospinal fluid (CSF). We aimed to validate the threshold cycle (Ct) cut-off points; calculate the operational characteristics of real-time PCR for detection of M. tuberculosis (MTb qPCR) in the CSF; and the inhibitory affect of CSF red blood cells (RBC) and total proteins on MTb qPCR. Methods A total of 334 consecutive participants were enrolled. Based on clinical, laboratory and imaging data, cases of suspected TBM were categorized as definite, probable, possible or not TBM cases. Receiver operating characteristic curve analysis was used to select the best discriminating Ct value. Results For TBM cases categorized as definite or probable (n=21), the Ct validated for CSF (≤39.5) improved the diagnostic performance of MTb qPCR on CSF samples. The sensitivity was 29%, specificity was 95%, positive predictive value was 26%, negative predictive value was 95%, efficiency was 90% and positive likelihood was 5.3. The CSF RBC and total protein did not affect the positivity of the MTb qPCR. Conclusions These data support the validation of a highly specific but low sensitive MTb qPCR assay for the TBM diagnosis using CSF samples. MTb qPCR contributes significantly to the diagnosis, mainly when associated with conventional microbiology tests and clinical algorithms.

Nested polymerase chain reaction for detection of pathogenic leptospires

2006 ◽  
Vol 52 (8) ◽  
pp. 747-752 ◽  
Author(s):  
Sandra Denize Dorneles Jouglard ◽  
Simone Simionatto ◽  
Fabiana Kommling Seixas ◽  
Fernanda Lima Nassi ◽  
Odir Antônio Dellagostin
Keyword(s):  
Polymerase Chain Reaction ◽  
Nested Pcr ◽  
Early Stage ◽  
Diagnostic Methods ◽  
Chain Reaction ◽  
Pcr Assay ◽  
Nested Polymerase Chain Reaction ◽  
Pathogenic Leptospira ◽  
Polymerase Chain ◽  
Low Sensitivity

Leptospirosis is a widespread zoonosis caused by pathogenic members of the genus Leptospira that has a great impact on human and veterinary public health. Early diagnosis of leptospirosis is important because severe lepto spiral infection can have a fulminant course. The available serological techniques for the diagnosis of leptospirosis have low sensitivity during the early stage of the disease. Efforts are being made to develop simpler, effective, efficient, and inexpensive diagnostic methods. In this work, we first evaluate a polymerase chain reaction (PCR) based method for diagnosis of leptospirosis. Primers were designed to amplify a 264 bp region within the lipL32 gene that is conserved among pathogenic Leptospira and absent in nonpathogenic species. The sensitivity and specificity of the assay were evaluated using 7 saprophytic serovars, 37 pathogenic serovars, and 15 other microorganisms. The method was very specific for pathogenic serovars, however, it lacked sensitivity. To enhance the sensitivity, another primer pair was designed to amplify a 183 bp region within the 264 bp region of the lipL32 gene and was used in a nested PCR assay. This approach was much more sensitive than conventional PCR.Key words: leptospirosis, diagnosis, nested PCR, lipL32.

scholarly journals Cerebrospinal Fluid Bacillary Load by Xpert MTB/RIF Ultra Polymerase Chain Reaction Cycle Threshold Value Predicts 2-Week Mortality in Human Immunodeficiency Virus–Associated Tuberculous Meningitis

2020 ◽  
Author(s):  
Emily M Martyn ◽  
Ananta S Bangdiwala ◽  
Enock Kagimu ◽  
Morris K Rutakingirwa ◽  
John Kasibante ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Polymerase Chain Reaction ◽  
Cerebrospinal Fluid ◽  
Tuberculous Meningitis ◽  
World Health ◽  
Chain Reaction ◽  
Cycle Threshold ◽  
Risk Of Death ◽  
Immunodeficiency Virus ◽  
Polymerase Chain

Abstract Background The World Health Organization recommends GeneXpert MTB/RIF Ultra (Xpert Ultra), a fully automated polymerase chain reaction (PCR) assay, as the initial tuberculous meningitis (TBM) diagnostic test. The assay’s PCR cycle threshold (Ct) values represent the number of PCR cycles required for probe signal to be detected (low Ct value = high bacillary load) and may approximate tuberculosis (TB) bacillary load. We measured the relationship between cerebrospinal fluid (CSF) TB bacillary load with mortality. Methods We prospectively enrolled 102 human immunodeficiency virus (HIV)–positive Ugandans with probable or definite TBM from April 2015 to August 2019. Xpert Ultra Ct tertiles and semi-quantitative categories were separately analyzed as predictors of 2-week mortality. We investigated associations between Ct and baseline clinical and CSF parameters. Results Subjects with Ct values in the low tertile (ie, high bacillary load) had 57% 2-week mortality—worse than the intermediate (17%) and high (25%) Ct tertiles and Xpert Ultra–negative (30%) probable TBM cases (P = .01). In contrast, the reported semi-quantitative Xpert Ultra categorization was less precise; with the medium to low category trending toward worse 2-week survival (42%) compared with very low (28%), trace (26%), and negative (30%) categories (P = .48). Ct tertile was significantly associated with baseline CSF lactate (P = .03). Conclusions High CSF TB bacillary load, as measured by Xpert Ultra Ct tertile, is associated with an almost 2-fold higher 2-week mortality in HIV-associated TBM and is a better predictor than the reported Xpert Ultra semi-quantitative category. Xpert Ultra Ct values could identify TBM patients at increased risk of death who may benefit from enhanced supportive care.

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