Normalised quantitative polymerase chain reaction for diagnosis of tuberculosis-associated uveitis

Qualitative and Quantitative Detection of Multiple Sexually Transmitted Infection Pathogens Reveals Distinct Associations with Cervicitis and Vaginitis

Many diverse pathogens have been discovered from reproductive-tract infections, but the relationship between the presence and abundance of particular pathogen species and disease manifestations is poorly defined. The present work examined the association of multiple common pathogens causing sexually transmitted infections (STIs) with cervicitis and vaginitis. The presence and abundance of 15 STI pathogens and the genotypes of human papillomavirus were determined in a cohort of 944 women that included 159 cervicitis patients, 207 vaginitis patients, and 578 healthy controls. Logistic regression and random forest models were constructed and validated in a separate cohort of 420 women comprising 52 cervicitis patients, 109 vaginitis patients, and 259 healthy controls. The frequency of individual STI pathogen species varied among the symptomatic patients and healthy controls. Abundance determination was necessary for most pathogens that were associated with the studied diseases. STI pathogens were more commonly associated with cervicitis than with vaginitis. Pathogen identification- and quantification-based diagnosis was observed for cervicitis with high sensitivity and specificity, but for vaginitis, the assay results would need to be combined with results of other diagnostic tests to firmly establish the pathogen-disease correlation. Integrated qualitative and quantitative detection of a selected panel of common STI pathogens can reveal their association with cervicitis and vaginitis. STI pathogen identification and quantification can be used to diagnose cervicitis and also help improve correct diagnosis of vaginitis. IMPORTANCE Scarce information exists with regard to whether STI pathogens can be defined as valid microbiological predictive markers for the diagnosis of cervicitis and vaginitis. We therefore conducted this study to assess the presence and abundance of a wide range of STI pathogens among patients having these two diseases and healthy controls as well. High sensitivity and specificity were observed for cervicitis by pathogen identification- and quantification-based diagnosis. In contrast, the assay results obtained for vaginitis would need to be combined with test results obtained by other diagnostic methods to decisively establish the pathogen-disease correlation. Simultaneous qualitative and quantitative detection of a selected panel of common STI pathogens and further coupling with machine learning models is worthwhile for establishing pathogen-based diagnosis of gynecological inflammations, which could be of great value in guiding the rational use of antimicrobials to control the spread of STIs.

BTS clinical statement for the diagnosis and management of ocular tuberculosis

The BTS clinical statement for the diagnosis and management of ocular tuberculosis (TB) draws on the expertise of both TB and and ophthalmic specialists to outline the current understanding of disease pathogenesis, diagnosis and management in adults. Published literature lacks high-quality evidence to inform clinical practice and there is also a paucity of data from animal models to elucidate mechanisms of disease. However, in order to improve and standardise patient care, this statement provides consensus points with the currently available data and agreed best practice.

Tubercular DNA PCR of ocular fluids and blood in cases of presumed ocular tuberculosis: a pilot study

Background:

The definitive diagnosing of ocular tuberculosis (TB) is difficult; therefore, there is a need of better understanding of investigating TB DNA in presumed ocular TB patients.

Objectives:

The aim of this study is to correlate tubercular DNA PCR of aqueous/vitreous and blood in cases of presumed ocular TB.

Design:

A prospective study.

Methods:

DNA was extracted from aqueous of cases of choroidal tuberculoma (group 1) and serpiginous choroiditis (group 2) and from vitreous of cases of vasculitis (group 3) and macular hole/retinal detachment (group 4). Gel-based PCR and real-time PCR amplification were performed using IS6110 primer on ocular fluids. The same was also performed on the blood samples of cases in which tubercular DNA was detected in the ocular fluids.

Results:

Overall, 31 cases were analysed in our study. Tubercular DNA was detected in ocular fluids of seven cases: group 1, two cases (67%); group 2, one case (17%); group 3, four cases (27%); and no case of group 4. Blood samples of six of these seven patients were positive for tubercular DNA. Of these six patients, four had evidence of systemic TB and were on ATT. Two cases had no evidence of active systemic TB, yet PCR was positive from blood and ocular fluids.

Conclusion:

Tubercular DNA detected from ocular fluids may possibly be due to bystander DNA and may not indicate primary ocular tubercular infection. Thus, caution must be exercised prior to labelling a case of uveitis as being tubercular based on the results of molecular assays on ocular fluids alone. The results of PCR on ocular fluids should be correlated with PCR on blood and systemic findings.

The diagnostic value of polymerase chain reaction for ocular tuberculosis diagnosis in relation to antitubercular therapy response: a meta-analysis

BACKGROUND

Polymerase chain reaction (PCR) is currently considered the method of choice for diagnosing ocular tuberculosis. However, the sensitivity and specificity of PCR using ocular samples remain uncertain. Our meta-analysis aimed to review the diagnostic accuracy of PCR testing in confirming ocular tuberculosis, with responses to antitubercular therapy (ATT) as reference indices.

METHODS

A systematic literature search of the PubMed, EBSCOHost, Scopus, and Google Scholar databases was performed using the standardized PRISMA guideline. Observational studies reporting both PCR MTb positivity and ATT response were included. Meta-analysis was performed to estimate the pooled positivity rate, sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratios (DOR), and summary receiver operating curves (SROC).

RESULTS

The pooled positivity rate for PCR MTb was 0.55 (95% CI 0.44-0.67). The overall sensitivity and specificity were 88% (95% CI 83-92) and 71% (95% CI 60-80), respectively. The pooled DOR was 12.15 (95% CI 5.55-26.62). The area under the SROC was 0.83.

CONCLUSIONS

The diagnostic accuracy of PCR Mtb is not sufficient for use as a benchmark for ocular TB diagnosis routinely based on ATT response. A negative result may help avoid prescribing unnecessary ATT in dilemmatic cases.

Recent Advances in Diagnosis and Treatment of Infectious Uveitis Prevalent in Asia-Pacific Region

ABSTRACT

The role of infections in intraocular inflammation is being increasingly recognized across the world. The Asia-Pacific region, being the single largest and most populous geographical entity on the planet, is home to a wide variety of such infections. Not surprisingly, there has been an explosion in the literature on infectious uveitis emerging from Asia-Pacific countries. In this review, we have covered recent advances in the diagnosis, treatment, and pathogenesis of common forms of infectious uveitis from the Asia-Pacific region. Much of the literature is focussed on the diagnosis of these infections by clinical criteria and laboratory investigations. There has also been an increased emphasis on the application of newer modes of ocular imaging and understanding pathomechanisms of ocular inflammation in these infections. Together this research has significantly improved our understanding of the diagnosis and management of infectious uveitis.

Pathogenesis of ocular tuberculosis: New observations and future directions

Ocular tuberculosis (OTB) encompasses all forms of intra- and extra-ocular inflammation associated with Mycobacterium tuberculosis (Mtb) infection. However, the organism is rarely found in ocular fluid samples of diseased eyes, rendering the pathomechanisms of the disease unclear. This confounds clinical decision-making in diagnosis and treatment of OTB. Here, we critically review existing human and animal data related to ocular inflammation and TB pathogenesis to unravel likely pathomechanisms of OTB. Broadly there appear to be two fundamental mechanisms that may underlie the development of TB-associated ocular inflammation: a. inflammatory response to live/replicating Mtb in the eye, and b. immune mediated ocular inflammation induced by non-viable Mtb or its components in the eye. This distinction is significant as in direct Mtb-driven mechanisms, diagnosis and treatment would be aimed at detection of Mtb-infection and its elimination; while indirect mechanisms would primarily require anti-inflammatory therapy with adjunctive anti-TB therapy. Further, we discuss how that most clinical phenotypes of OTB likely represent a combination of both mechanisms, with one being predominant than the other.

The Emerging Challenge of Diagnosing Drug-resistant Tubercular Uveitis: Experience of 110 Eyes from North India

Background: Rapid and timely diagnosis of tubercular uveitis (TBU) is of paramount importance to save these eyes from blindness. The present study was, therefore, undertaken to carry out a comparative evaluation of Gene Xpert MTB/RIF (Xpert), MTBDRplus and Multiplex PCR (MPCR) for the diagnosis of TBU. These tests were performed on vitreous fluid of 110 patients with presumed TBU and 90 controls. rpoB gene sequencing confirmed Rifampicin resistance.Results: Xpert, MTBDRplus and MPCR were positive in 19(17.2%),38 (34.5%) and 79 (71.8 %) patients, respectively. All tests were negative in all controls. Rif resistance was detected in 3 by Xpert and 7 by MTBDRplus. MPCR followed by rpoB gene sequencing detected Rif resistance in 6 cases. One case of false Rif resistance was reported each by MTBDRplus and Xpert.Conclusion: MPCR followed by rpoB sequencing is a robust technique for the diagnosis of paucibacilliary condition like TBU and reliable detection of drug resistance.