Outcome of polymerase chain reaction (PCR) analysis in 100 suspected cases of infectious uveitis

Evolution of research in diagnosis and management of uveitis over four decades in India

Uveitis and its complications are more common in the developing world, in which the condition occurs in up to 714 per 100,000 in the population and accounts for up to 25% of all blindness. In India, the ophthalmic sub speciality of uveitis greatly evolved in the last four decades. In the early decades most of the studies were epidemiological studies. In recent years, more research has been published due to tremendous advancements in clinical diagnosis, laboratory investigations and ancillary test and treatment modalities. In this review article, we did a medline search with key words 'uveitis' and 'India', and selectively incorporated articles showing the evolution of this sub-speciality in India.

Polymerase chain reaction test for diagnosis of infectious uveitis

BACKGROUND

To study the clinical utility of broad-range real-time Polymerase Chain Reaction (PCR) assay in patients suspected for infectious uveitis and to analyze the clinical relevance.

METHODS

Medical records of patients with uveitis were assessed in whom PCR analysis of intraocular fluids was performed between January 2018 and February 2021. Intraocular samples were investigated for cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella zoster virus (VZV), herpes simplex viruses type 1 and 2 (HSV_1,2), human T-lymphotropic virus type 1 (HTLV-1), Toxoplasma gondii and also for bacterial 16 S and fungal 18 S/28S ribosomal DNA (rDNA).

RESULTS

Aqueous paracentesis and vitreous sampling was done for 151 (81.2%) and 35 (18.8%) patients, respectively. Most of the patients had panuveitis (61.3%). PCR results were positive in 69 out of 186 patients (37%) according to the following order: CMV (18 cases), VZV (18 cases), fungal 18s/28s rDNA (17 cases), HSV (9 cases), bacterial 16s rDNA (3 cases), HTLV-1 (2 cases), and Toxoplasma gondii (2 cases). PCR positivity rate was 5.8% in patients with undifferentiated panuveitis. EBV was not detected at all. Initial treatment was changed in 38 patients (20%) based on PCR results. The overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of PCR test for aqueous samples was 82%, 91%, 96%, and 87%, respectively. No significant adverse effect related to sampling was reported.

CONCLUSION

PCR analysis of intraocular fluids in patients with suspected infectious uveitis plays an important role in confirming diagnosis or changing treatment with good predictive value. However, routine PCR test in patients with undifferentiated panuveitis in order to rule out possible underlying infectious etiology had low benefit.

Polymerase chain reaction confirmed mycobacterium tuberculosis intermediate uveitis - analysis of 22 eyes of 14 cases from a tertiary care centre in South India: a retrospective study

Background

To report the role of Polymerase Chain Reaction in confirming the diagnosis of presumed Mycobacterium Tuberculosis (MTB) Intermediate Uveitis.

Method

Retrospective analysis of 22 eyes of 14 cases of presumed tubercular intermediate uveitis wherein intraocular fluid was tested for MTB DNA by Nested & Real-time PCR, based on clinical suspicion of tubercular aetiology. QuantiFERON TB gold test and High-Resolution CT Chest were done. Patients were treated with anti-tubercular therapy with oral steroids & immunomodulators. In the study, eleven were male (79%) and three female (21%). The median age was 34 years. Nested PCR for both IS 6110 & MPB 64 was positive in 64% of the cases, IS 6110 positive in 23% and MPB 64 positive in 15%. Real-time PCR was positive in 48% of the cases. Vision improved in 33% of cases, maintained in 57%, and worsened in 10% of cases.

Conclusion

Presumed Tubercular intermediate uveitis can be confirmed by PCR of intraocular fluids. Anti-tubercular therapy with immunosuppression can improve vision and prevent recurrences in such cases.

Changing Trends in Uveitis in the United Kingdom: 5000 Consecutive Referrals to a Tertiary Referral Centre

PURPOSE

To demonstrate changes in the demography and diagnosis of uveitis in a specialist clinic in the United Kingdom.

METHODS

Retrieval of data including all new referrals to Manchester Uveitis Clinic from 1991 to 2020. The incidence and proportions of diagnoses between 4 quartiles was compared.

RESULTS

5000 patients with uveitis were seen. Referral rates trebled over time. Highly significant increases in referrals were seen for multiple evanescent white dot syndrome-spectrum disorders, syphilis and tuberculosis; increases were also seen for herpetic retinitis, vitreoretinal lymphoma and sarcoidosis. Highly significant decreases were seen for Fuchs' uveitis, Behçet's uveitis and ocular toxoplasmosis.

CONCLUSIONS

Subspecialisation and de-skilling has changed referral patterns to specialist clinics; changes cannot be entirely attributed to disease incidences, which also vary between countries. International data are non-comparable. There are clear changes in referral patterns and disease incidence in this population, influenced by evolving diagnosis. Local data should steer care planning.

Ocular Manifestations of Chikungunya Infection: A Systematic Review

The Chikungunya virus (CHIKV) can cause long lasting symptoms and manifestations. However, there is little information on which ocular ones are most frequent following infection. We performed a systematic review (registered in the International Prospective Register of Systematic Reviews; no CRD42020171928) to establish the most frequent ocular manifestations of CHIKV infection and their associations with gender and age. Articles published until September 2020 were selected from PubMed, Scielo, Cochrane and Scopus databases. Only studies with CHIKV-infected patients and eye alterations were included. Reviews, descriptive studies, or those not investigating the human ocular manifestations of CHIKV, those with patients with other diseases and infections, abstracts and studies without relevant data were excluded. Twenty-five studies were selected for inclusion. Their risk of bias was evaluated by a modified Newcastle-Ottawa scale. The most frequent ocular symptoms of CHIKV infection included ocular pain, inflammation and reduced visual acuity, whilst conjunctivitis and optic neuritis were the most common manifestations of the disease. These occurred mostly in individuals of 42 ± 9.5 years of age and woman. The few available reports on CHIKV-induced eye manifestations highlight the need for further research in the field to gather more substantial evidence linking CHIKV infection, the eye and age/gender. Nonetheless, the data emphasizes that ocular alterations are meaningful occurrences of CHIKV infection which can substantially affect quality of life.

The impact of polymerase chain reaction (PCR) on diagnosis and management of infectious uveitis at a tertiary care facility

BACKGROUND

Polymerase Chain Reaction (PCR) is a well-accepted adjunct in the management of infectious uveitis. In turn, few reports in the literature have evaluated how PCR then impacts patient care. This study aims to evaluate the impact of PCR sampling on diagnosis and treatment of infectious uveitidies at a large tertiary care facility.

MAIN BODY

This is a retrospective, observational study of patients with aqueous and vitreous PCR samples obtained from 2014 to 2019. The study was undertaken at a single institution. At least one follow up visit following results of PCR testing was required for inclusion. If a patient had multiple PCR samples taken, only the first sample was included. The patients were divided into three categories based on pre-sampling diagnosis. A chi-square test was used to analyze the data. 108 cases were available for analysis. PCR did not change diagnosis or management in any of the cases where pre-sampling diagnosis carried a high clinical suspicion for negative PCR. Overall, the results of PCR testing had a more significant impact on diagnosis in those cases where pre-sampling diagnosis was unknown versus those where it was confirmatory in nature, thus presumed to be related to an infectious entity tested by PCR (74% vs. 29%, p = 0.00006). The rate of treatment change based on PCR was similar between those cases where there was a high clinical suspicion for positive PCR and those where pre-sampling diagnosis was unknown (32% vs. 33%, p = 0.95). Further analyzing specimens separately depending on source of sample, this pattern persisted for aqueous samples, with PCR showing a more significant impact on diagnosis in those cases where the diagnosis was unknown versus those where sampling was confirmatory (86% vs. 31%, p = 0.00004). The rate of change in treatment between the two groups was similar (35% vs. 31%, p = 0.79). Vitreous samples followed a similar pattern with a higher rate of diagnosis change for those cases where pre-sampling diagnosis was unknown and a similar rate in treatment change between the two groups, however this did not reach statistical signifigance (44% vs. 25%, p = 0.28; 27% vs. 33%, p = 0.74).

CONCLUSION

There is no well-defined algorithm as to when to employ PCR testing in uveitis. As expected, in our experience, it has the largest impact on diagnosis when the diagnosis is unknown, however even when confirmatory in nature, it continues to impact patient management.

Infectious Uveitis after Local Steroid and/or Methotrexate Injections at A Tertiary Referral Center in New Zealand: A Case Series

Aim: Infectious uveitis is one of the most visually devastating causes of uveitis worldwide and accounts for 19.6% of all cases of uveitis in New Zealand. With the burgeoning use of intravitreal injections, there has been a commensurate increase in the number of injection-related complications and reports of infectious uveitis following their administration in recent years. We present a case series of four patients with infectious uveitis after local injections.Method: We retrospectively reviewed the data of four patients (mean age, 67.25 ± 7.58 years) who presented to the department of ophthalmology at Auckland District Health Board with infectious uveitis which occurred or worsened after local triamcinolone acetonide (TA) and/or methotrexate (MTX) injections.Results: Three patients received local TA and one patient received intravitreal MTX. All patients were immunosuppressed prior to treatment. Two patients had toxoplasma chorioretinitis which worsened with local TA and one patient developed cytomegalovirus (CMV) retinitis after intravitreal TA. The last patient had syphilis retinopathy which worsened with intravitreal MTX. There were atypical presentations, as demonstrated by a case of presumed birdshot chorioretinopathy flare which tested positive for toxoplasma chorioretinitis with polymerase chain reaction (PCR).Conclusion: Uveitis due to infectious etiologies needs to be carefully excluded prior to the use of local steroid and/or methotrexate injections. Disease presentations may be atypical in the presence of marked immunosuppression following local therapy. Polymerase chain reaction (PCR) can play an important role in the diagnosis in this setting.

Exploration of Anti-infectives From Mangrove-Derived Micromonospora sp. RMA46 to Combat Vibrio cholerae Pathogenesis

Vibrio cholerae, the etiological agent of cholera, employs quorum sensing (QS) pathways to control the expression of virulence factors, including the production of cholera toxin and biofilm formation. Acquired antibiotic resistance in V. cholerae draws attention to the development of novel therapeutics that counteract virulence, rather than the viability of the pathogen. In this context, we explored the anti-infective potential of rare marine Actinobacteria (RMA) from a mangrove ecosystem. Here, we report the effects of Micromonospora sp. RMA46 against V. cholerae in vitro. The RMA46 organic extract was non-bactericidal to V. cholerae cells and non-cytotoxic to macrophage RAW264.7 cell lines. RMA46 inhibited the formation of V. cholerae biofilms and downregulated the QS global switches LuxO and HapR, as well as other virulence genes including ct, tcp, and hapA. In silico molecular docking simulation of RMA46 ethyl acetate extract with LuxO and HapR revealed that 2-methoxy-4-vinylphenol and hexahydro-3-(phenylmethyl)-pyrrolo[1,2-a]pyrazine-1,4-dione could interact with the active sites of LuxO and HapR and potentially inhibit them. This study highlights Micromonospora sp. RMA46 as a potential source of anti-infectives against V. cholerae.

Coats-like response in tubercular subretinal abscess masquerading as melanoma as the initial manifestation of miliary tuberculosis

Ocular neoplasia can masquerade as an inflammatory condition and vice-versa, which if untreated, can lead to loss of vision or even life. We present a young immunocompetent adult male referred to us as choroidal melanoma. He had a large atypical choroidal mass and exudative retinal detachment. He had no systemic complaints and ocular lesions were the first manifestation of disseminated disease. Aqueous polymerase chain reaction for Mycobacterium tuberculosis (MTB) was negative, but Mantoux, chest radiology, acid-fast bacilli, and caseation necrosis on pleural nodule histopathology confirmed tuberculosis (TB). While on antitubercular therapy, a rare “Coats'-like response” was noted which eventually resolved completely with treatment.

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.

Performance of 2 Polymerization Protocols Targeting Cloned Toxoplasma Parasites

BACKGROUND

Toxoplasma gondii is a common parasitic infection of humans. Infection is usually mild. Serious complications can occur in pregnant and immunocompromised patients.

AIM

The present study aims to investigate the performance of 2 different PCR protocols; real-time quantitative molecular assays (qPCR) and conventional molecular assays (cPCR), using 2 different sets of primers and by using cloned purified Toxoplasma genomic substances to be evaluated as reference samples.

METHODS

The target DNA was provided in 8 different quantities.

RESULTS

Amplification failure was reported only with the cPCR in samples of low concentrations using both primer sets. Quantitative PCR detected the 8 different dilutions of the purified Toxoplasma gondii using the 2 sets of primers while cPCR was sensitive to detect only 6 different dilutions.

CONCLUSION

Generally real-time quantitative molecular assays, is easy to use method compared to conventional PCR assay and produces more reliable results within only one hour time but still the possible application of qPCRs in routine diagnosis necessitates analysis of a large number of clinical samples in further studies to make the proper choice.