Evaluation of Host Protein Biomarkers by ELISA From Whole Lysed Peripheral Blood for Development of Diagnostic Tests for Active Tuberculosis

Tuberculosis (TB) remains a significant global health crisis and the number one cause of death for an infectious disease. The health consequences in high-burden countries are significant. Barriers to TB control and eradication are in part caused by difficulties in diagnosis. Improvements in diagnosis are required for organisations like the World Health Organisation (WHO) to meet their ambitious target of reducing the incidence of TB by 50% by the year 2025, which has become hard to reach due to the COVID-19 pandemic. Development of new tests for TB are key priorities of the WHO, as defined in their 2014 report for target product profiles (TPPs). Rapid triage and biomarker-based confirmatory tests would greatly enhance the diagnostic capability for identifying and diagnosing TB-infected individuals. Protein-based test methods e.g. lateral flow devices (LFDs) have a significant advantage over other technologies with regard to assay turnaround time (minutes as opposed to hours) field-ability, ease of use by relatively untrained staff and without the need for supporting laboratory infrastructure. Here we evaluate the diagnostic performance of nine biomarkers from our previously published biomarker qPCR validation study; CALCOCO2, CD274, CD52, GBP1, IFIT3, IFITM3, SAMD9L, SNX10 and TMEM49, as protein targets assayed by ELISA. This preliminary evaluation study was conducted to quantify the level of biomarker protein expression across latent, extra-pulmonary or pulmonary TB groups and negative controls, collected across the UK and India, in whole lysed blood samples (WLB). We also investigated associative correlations between the biomarkers and assessed their suitability for ongoing diagnostic test development, using receiver operating characteristic/area under the curve (ROC) analyses, singly and in panel combinations. The top performing single biomarkers for pulmonary TB versus controls were CALCOCO2, SAMD9L, GBP1, IFITM3, IFIT3 and SNX10. TMEM49 was also significantly differentially expressed but downregulated in TB groups. CD52 expression was not highly differentially expressed across most of the groups but may provide additional patient stratification information and some limited use for incipient latent TB infection. These show therefore great potential for diagnostic test development either in minimal configuration panels for rapid triage or more complex formulations to capture the diversity of disease presentations

Seroprevalence of syphilis in patients attending a tertiary care hospital in Southern India

Objective: To report our experience with two tests, anti-cardiolipin antibody test [venereal disease reasearch laboratory (VDRL) test] and specific treponemal test (Treponema pallidum hemagglutination assay), used for screening antenatal, high risk cases and cases from sexually transmitted infection in a tertiary care hospital from January 2006 till December 2008. Methods: A total of 14 639 samples received from various patient groups including antenatal cases, patients attending sexually transmitted disease (STD) clinic, blood donors and HIV positive patients were screened. Results: Among the 14 639 samples collected, 103 were positive by VDRL test. Of these 89 cases were confirmed by quantitative VDRL test and Treponema pallidum hemagglutination assay. The cumulative seroprevalence over two years was found to be 0.61% in this study. The syphilis seroprevalence reduced from 0.88% in 2006 to 0.40% in 2008. Among the various sub-populations studied, patients attending the sexually transmitted infection clinic showed a seroprevalence of 2.62%. The seroprevalence decreased significantly from 4.00% in 2006 to 1.39% in 2008. Conclusions: Our study showed a statistically significant declining rate of syphilis in STD clinics as well as the overall seroprevalence. These findings could be interpreted as indicators of improved programmes for prevention and management of STDs

Case Report Streptomyces bacteremia in a patient with actinomycotic mycetoma

A 29-year-old woman presented with multiple painful swelling with discharging sinuses over the scalp. Histopathological examination of the biopsy tissue was suggestive of actinomycotic mycetoma. Streptomyces spp. was isolated from blood culture. The patient was successfully treated with trimethoprim-sulfamethoxazole and crystalline penicillin. This case is reported because of the rare occurrence of bacteremia by Streptomyces spp. secondary to subcutaneous actinomycotic mycetoma. Moreover, an interesting association between successive two pregnancies and occurrence of mycetoma of the scalp was observed in this case

Efficacy of intraoperative vancomycin in irrigating solutions on aqueous contamination during phacoemulsification

Purpose: To study the efficacy of adding vancomycin in irrigating solutions, in comparison to topical antibiotic given preoperatively for a day, during phacoemulsification, in reducing the anterior chamber (AC) contamination. Settings and Design: This was a prospective, interventional, hospital-based study. Materials and Methods: This was a study involving 400 eyes of 400 paitens, undergoing routine phacoemulsification between January 2004 and June 2006. The patients were non-randomly assigned to two groups: Group 1 included 180 patients, who received topical ciprofloxacin eye-drops (four-hourly) for a day preoperatively and Group 2 included 220 patients, who underwent phacoemulsification with vancomycin (20 µg/ml) in the irrigating solution. Anterior chamber aspirate obtained at the end of the surgery was sent for microbial workup. The number of positive cultures in both the groups was determined. Statistical analysis: This was performed using Chi-square test. Results: Aqueous samples showed microbial growth in 38 (21.1%) out of 180 eyes in Group 1 and in 17 (7.7%) out of 220 eyes in Group 2 ( P = 0.001). Coagulase-negative staphylococcus was the most common organism in both the groups. Aqueous samples from four eyes in group 1 showed multiple organisms, while none of the sample from group 2 showed more than one organism. None of the eyes in either group showed fungal contamination. One patient in Group 1 developed endophthalmitis, and the causative organism was Alcaligenes faecalis. All patients were followed up for a minimum of six months (range: 6 to 14 months and mean: 9.3 months). Conclusion: Addition of vancomycin in irrigating solutions is more efficacious in reducing AC contamination in comparison to topical antibiotic administered a day preoperatively

Original Article Clinical and serological evaluation of leptospirosis in Puducherry, India

Background: Leptospirosis is a zoonotic disease with a worldwide distribution. There is a paucity of available data about prevalence of this disease in Pondicherry. Our aim was to investigate the seropositivity rate of leptospirosis in suspected cases and also to identify the predominant serogroups present by performing Microscopic Agglutination Test (MAT). The other aim of this study was to compare the results of a commercially available IgM ELISA with that of MAT. Methodology: A total of 110 blood samples from patients suspected of leptospirosis were sent for diagnosis. These samples were subjected to IgM ELISA and the microscopic agglutination test (MAT). MAT was done using a panel of 12 Leptospira serovars. Results: MAT analysis of the 110 samples showed 40 (36%) to be positive. Antibodies were predominantly seen against serogroup Leptospira Icterohemorrhagiae (27%), followed by Pomona (17%), and Pyrogenes (12%). IgM ELISA done on these samples showed a positivity of 37% compared to MAT. Conclusion: This study reveals that the MAT test can be standardized in a diagnostic laboratory and used in conjunction with an IgM ELISA