Limits of Detection of Mycobacterium tuberculosis in Spiked Cerebrospinal Fluid Using the Polymerase Chain Reaction in Tuberculous Meningitis

2000 ◽  
Vol 19 (1) ◽  
pp. 47-50 ◽  
Author(s):  
J. Baran Jr. ◽  
K. M. Riederer ◽  
R. Khatib

2019 ◽  
Vol 57 (4) ◽  
pp. 556-564 ◽  
Author(s):  
Sérgio M. de Almeida ◽  
Conrado M. Borges ◽  
Lucas B. Santana ◽  
Gilberto Golin ◽  
Lísia Correa ◽  
...  

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.



1995 ◽  
Vol 242 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Juei-Jueng Lin ◽  
Horng-Jyh Harn ◽  
Yaw-Don Hsu ◽  
Wen-Long Tsao ◽  
Herng-Sheng Lee ◽  
...  


Author(s):  
Emily M Martyn ◽  
Ananta S Bangdiwala ◽  
Enock Kagimu ◽  
Morris K Rutakingirwa ◽  
John Kasibante ◽  
...  

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.



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 ◽  
...  

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.



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