A novel aptamer-based test for the rapid and accurate diagnosis of pleural tuberculosis.

Pleural tuberculosis (pTB) is diagnosed by using a composite reference standard (CRS) since microbiological methods are grossly inadequate and an accurate diagnostic test remains an unmet need. The present study aimed to evaluate the utility of Mycobacterium tuberculosis (Mtb) antigen and DNA-based tests for pTB diagnosis. Patients were classified as 'Definite TB', 'Probable TB' and 'Non-TB' disease according to the CRS. We assessed the performance of in-house antigen detection assays, namely antibody-based Enzyme-Linked ImmunoSorbent Assay (ELISA) and aptamer-based Aptamer-Linked Immobilized Sorbent Assay (ALISA), targeting Mtb HspX protein and DNA-based tests namely, Xpert MTB/RIF and in-house devR-qPCR. ROC curves were generated for the combined group of 'Definite TB' and 'Probable TB' vs. 'Non-TB' disease group and cut-off values were derived to provide specificity of ≥98%. The sensitivity of ALISA was ∼93% vs. ∼24% of ELISA (p-value ≤0.0001). devR-qPCR exhibited a sensitivity of 50% vs. ∼22% of Xpert (p-value ≤0.01). This novel aptamer-based ALISA test surpasses the sensitivity criterion and matches the specificity requirement spelt out in the 'Target product profile' for extrapulmonary tuberculosis samples by Unitaid (Sensitivity ≥80%, Specificity 98%). The superior performance of the aptamer-based ALISA test indicates its translational potential to bridge the existing gap in pTB diagnosis.

Epstein-Barr virus-induced haemophagocytic syndrome.

Haemophagocytic syndrome or haemophagocytic lymphohistiocytosis is a disorder of histiocytes that has sepsis-like features, combined with haemophagocytosis, cytopenias, hyperferritinaemia, hypercytokinaemia and splenomegaly. Diagnostic, therapeutic and prognostic guidelines are available for childhood (familial) haemophagocytic syndrome. The disorder is diagnosed less frequently among adults than children. We report a case of Epstein-Barr virus-induced haemophagocytic syndrome in a 23-year-old man, who responded to treatment with steroids and chemotherapy.

Assessment of DNA aptamers targeting GlcB and HspX antigens for application in the diagnosis of abdominal tuberculosis.

The diagnosis of abdominal tuberculosis (aTB) is challenging and there is an urgent need for an accurate diagnostic test. We have developed a high affinity DNA aptamer against GlcB antigen of Mycobacterium tuberculosis (Mtb). We further compared the diagnostic utility of in-house-generated high affinity DNA aptamers and polyclonal antibodies against two Mtb antigens, namely GlcB and HspX, in ascitic fluid samples. These diagnostic reagents were assessed in patients (n = 94) who were categorized as 'Definite TB', 'Probable TB', 'Possible TB' (taken together as aTB) and 'Non-TB' disease. Receiver operating characteristic curves were used to derive cut-off values to provide ≥93% specificity. Aptamer Linked Immobilized Sorbent Assay (ALISA) for HspX and GlcB exhibited a sensitivity of ∼84% and 50%, respectively (p-value <0.01). In contrast, antibody-based ELISA exhibited a lower sensitivity of ∼18% and ∼28% for HspX and GlcB, respectively (p-value <0.0001 and p = 0.05 for HspX and GlcB ELISA vs. ALISA, respectively). HspX ALISA detected 32/38 aTB cases, while Xpert detected only 9 samples. In conclusion, HspX aptamer-based test was found to be superior to the other tests for diagnosing aTB and it nearly fulfils the sensitivity criteria of WHO's 'Target Product Profile' for extrapulmonary tuberculosis (sensitivity ≥80%, specificity 98%).

Utility of circulating cell-free Mycobacterium tuberculosis DNA for the improved diagnosis of abdominal tuberculosis.

Abdominal tuberculosis (ATB) continues to pose a major diagnostic challenge for clinicians due to its nonspecific clinical presentation, variable anatomical location and lack of sensitive diagnostic tools. In spite of the development of several assays till date; no single test has proved to be adequate for ATB diagnosis. In this study, we for the first time report the detection of circulating cell-free Mycobacterium tuberculosis (M. tuberculosis) DNA (cfMTB-DNA) in ascitic fluid (AF) samples and its utility in ATB diagnosis. Sixty-five AF samples were included in the study and processed for liquid culture, cytological, biochemical and molecular assays. A composite reference standard (CRS) was formulated to categorize the patients into 'Definite ATB' (M. tuberculosis culture positive, n = 2), 'Probable ATB' (n = 16), 'Possible ATB' (n = 13) and 'Non-TB' category (n = 34). Two molecular assays were performed, namely, the novel cfMTB-DNA qPCR assay targeting M. tuberculosis devR gene and Xpert MTB/RIF assay (Xpert), and their diagnostic accuracy was assessed using CRS as reference standard. Clinical features such as fever, loss of weight, abdominal distension and positive Mantoux were found to be strongly associated with ATB disease (p<0.05). cfMTB-DNA qPCR had a sensitivity of 66.7% (95% CI:40.9,86.7) with 97.1% specificity (95% CI:84.7,99.9) in 'Definite ATB' and 'Probable ATB' group collectively. The sensitivity increased to 70.9% (95% CI:51.9,85.8) in the combined 'Definite', 'Probable' and 'Possible' ATB group with similar specificity. The cfMTB-DNA qPCR assay performed significantly better than the Xpert assay which demonstrated a poor sensitivity of ≤16.7% with 100% (95% CI:89.7,100) specificity (p<0.001). We conclude that cfMTB-DNA qPCR assay is an accurate molecular test that can provide direct evidence of M. tuberculosis etiology and has promise to pave the way for improving ATB diagnosis.

A study of cardiovascular risk factors in Delhi, India.

Acute myocardial infarction (AMI) is a leading cause of mortality and disability of adults in urban and rural India, and occurs at younger age than in western populations. In this paper an attempt has been made to determine the risk factors for non- fatal AMI among Indian men and women and to study the difference in proportion of risk factors by taking non- AMI group along with healthy group as controls. Mantel Haenzel test showed that while comparing AMI with non-AMI group, diabetes mellitus (p < 0.05), family history of MI (p < 0.0001) and smoking (p < 0.0001) are significantly associated with AMI after adjusting the effects of hypertension. The same test was carried out in comparing AMI with healthy group which showed that diabetes mellitus (p < 0.05), family history of MI (p < 0.0001) and smoking (p < 0.0001) are significantly associated with AMI after adjusting the effects of hypertension. Similarly, while comparing CVD group with healthy group, family history of MI (p < 0.0001) and smoking (p < 0.0001) are significantly associated with CVD after adjusting the effects of hypertension. Stepwise logistic regression showed that while comparing AMI cases with non- AMI controls, arrhythmias (odds ratio (OR) = 5.196, p < 0.0001), angina (OR = 3.599, p < 0.0001), CHF (OR = 3.121, p < 0.0001), hypertension (OR = 2.717, p < 0.0001), smoking (OR = 1.993, p < 0.0001) and family history of MI (OR = 1.819, p < 0.01) were important risk factors for a first myocardial infarction. Moreover, while comparing AMI cases with healthy controls, family history of AMI (OR = 15.925, p < 0.0001), smoking (OR = 2.806, p < 0.001), hypertension (OR = 2.718, p < 0.0001), gender (OR = 2.410, p < 0.01) and age (OR = 2.410, p < 0.05) were important predictors of AMI; and while comparing CVD cases (AMI and non-AMI) with healthy group, family history of MI (OR = 10.377, p < 0.01), hypertension (OR = 8.237, p < 0.01) and smoking (OR = 4.454, p < 0.01), were important predictors of cardiovascular disease.

Evaluation of the WHO clinical case definition of AIDS among children in India.

The need of a clinical case definition (CCD) for Acquired Immunodeficiency Syndrome (AIDS) was felt by public health agencies to monitor diseases resulting from human immunodeficiency virus (HIV) infection. To test the statistical significance of the existing World Health Organization (WHO) CCD for the diagnosis of AIDS in areas where diagnostic resources are limited in India, a prospective study was conducted in the Paediatrics department at Dr. Ram Manohar Lohia Hospital, New Delhi. 360 cases between 18 months-12 years of age satisfying WHO case definitions of AIDS were included in the study group. Informed consent was taken from the parents. The serum of patients was subjected to ELISA to conform the diagnosis of HIV infection. Our study detected 16.66% (60) of HIV prevalence in children visiting paediatrics outpatient clinic. 20% cases manifested 3 major and 2 minor signs. This definition had a sensitivity of 73.33%, specificity of 90.66%, positive predictive value (PPV) of 61.11% and negative predictive value (NPV) of 94.44%. On using stepwise logistic regression analysis weight loss, chronic fever > 1 month and total lymphocyte count of less than 1500 cells/mm3 emerged as important predictors. Cases showing 2 major and 2 minor signs were 86 (23.89%) with a sensitivity and specificity of 86.66% and 88.66% respectively. Based on these findings, we propose a clinical case definition based on 13 clinical signs and symptoms for paediatric AIDS in India with better sensitivity and PPV than the WHO case definition but with almost similar specificity. Thus multicentric studies are further required to modify these criteria in Indian set up.

Prevalence of thyroid dysfunction and its correlation with CD4 count in newly-diagnosed HIV-positive adults--a cross-sectional study.

Prevalence of subclinical hypothyroidism in HIV-positive patients is reported to be high in those with severe immune deficiency. However, there is paucity of literature in newly-diagnosed HIV-positive population. Our aim was to estimate the prevalence of thyroid dysfunction and study its correlation with CD4 count in this population. In this cross-sectional study, patients presenting to the antiretroviral therapy clinic were screened with thyroid function tests, including thyroid stimulating hormone, free triiodothyronine, free thyroxine, and anti-thyroid peroxidase antibody levels at the time of diagnosis. Two hundred and twenty-five HIV-positive and an equal number of healthy volunteers were enrolled. The mean (SD) CD4 count in the study group was 147.1 (84) and 70.7% had advanced immune deficiency with CD4 count <200 cells/µL. The overall prevalence of thyroid dysfunction was 75.5% in the study group and 16% in the control group. Subclinical hypothyroidism was the commonest abnormality noted in almost 53%. Significant correlation was observed between CD4 count and thyroid stimulating hormone, free triiodothyronine, and free thyroxine levels (r = -0.86, r = 0.77, and r = 0.84, respectively, p < 0.0001 for all). The present study demonstrated high prevalence of thyroid dysfunction in HIV-positive patients. The dysfunction is subclinical in most cases and correlates well with declining CD4 counts.

Clinical, laboratory, and management profile in patients of liver abscess from northern India.

Objective. To describe the clinical profile, microbiological aetiologies, and management outcomes in patients with liver abscess. Methods. A cross-sectional study was conducted from May, 2011, to April, 2013, on 200 consecutive liver abscess patients at PGIMER and Dr. RML Hospital, New Delhi. History, examination, and laboratory investigations were recorded. Ultrasound guided aspiration was done and samples were investigated. Chi-square test and multivariate regression analysis were performed to test association. Results. The mean age of patients was 41.13 years. Majority of them were from lower socioeconomic class (67.5%) and alcoholic (72%). The abscesses were predominantly in right lobe (71%) and solitary (65%). Etiology of abscess was 69% amoebic, 18% pyogenic, 7.5% tubercular, 4% mixed, and 1.5% fungal. Percutaneous needle aspiration was done in 79%, pigtail drainage in 17%, and surgical intervention for rupture in 4% patients. Mortality was 2.5%, all reported in surgical group. Solitary abscesses were amoebic and tubercular whereas multiple abscesses were pyogenic (P = 0.001). Right lobe was predominantly involved in amoebic and pyogenic abscesses while in tubercular abscesses left lobe involvement was predominant (P = 0.001). Conclusions. The commonest presentation was young male, alcoholic of low socioeconomic class having right lobe solitary amoebic liver abscess. Appropriate use of minimally invasive drainage techniques reduces mortality.

Atypical respiratory complications of dengue fever.

In last decade, dengue has emerged as one of the most important vector born disease. With increasing cases, uncommon presentations and complications are now commonly recognized. Here, we report two cases of rare pattern of respiratory involvement in dengue: acute respiratory distress syndrome and bronchiolitis with respiratory failure.

Multidrug resistant citrobacter: an unusual cause of liver abscess.

Liver abscesses are infectious, space occupying lesions in the liver, the two most common abscesses being pyogenic and amoebic. A pyogenic liver abscess (PLA) is a rare condition with a reported incidence of 20 per 100 000 hospital admissions in the western population. The right lobe of the liver is the most common site in both types of liver abscess. Clinical presentation is elusive with complaints of fever, right upper quadrant pain in the abdomen and hepatomegaly with or without jaundice. The aetiology of PLA has changed in the past few decades and may be of biliary, portal, arterial or traumatic origin, but many cases are still cryptogenic. The most common organisms causing PLA are Gram-negative aerobes, especially Escherichia coli and Klebsiella pneumoniae. Studies have shown a high degree of antimicrobial susceptibility of isolated organism resulting in an overall lower mortality in PLA. Here, we present a case of PLA caused by multidrug-resistant Citrobacter freundii, which is an unusual organism to be isolated.

Guillain-Barre syndrome in an adult patient with Henoch-Schonlein purpura.

A 42-year-old man presented with pain in the abdomen, massive haematemesis and rashes over the body and development of bilateral lower limb weakness the next day. The patient was later diagnosed with Guillain-Barre syndrome with Henoch-Schonlein purpura. He was treated with intravenous immunoglobulins. At 3 months of follow-up and rehabilitation, patient showed complete recovery from weakness.

Changing patterns of cardiovascular risk factors and heart related sickness in relation with acute myocardial infarction in Delhi, India.

In this article an attempt has been made to investigate the 10-year trend of cardiovascular risk factors and common heart related sickness including angina, arrhythmias and congestive heart failure, and to study the impact of cardiovascular risk factors and heart related sickness on time between two acute myocardial infarctions. Chi-square test showed that in comparison to two 5-year study periods, the proportion of smoking, arrhythmias and congestive heart failure increased significantly in the second 5-year study period and the proportion of hypertension decreased significantly in the second 5-year study period. Moreover, with regard to occurrence of myocardial infarction under the age of 45 years, the prevalence decreased significantly in the second 5-year period. Cox regression model with time dependent covariates showed that gender, hypercholesterolaemia, congestive heart failure and arrhythmias were found to be important predictors associated with reduced time to second episode of myocardial infarction. The purpose of this study will help the physicians to detect the risk factors associated with reduced time between two myocardial infarctions after the occurrence of first episode of myocardial infarction so that by controlling the risk factors will either increase the duration between two myocardial infarctions or prevent the occurrence of second episode and hence improving the survival time of the patients.