Leprosy transmission in endemic and non-endemic areas
Leprosy transmission in endemic and non-endemic areas based on the profile of antibody response of PGL-1 and PCR detection of Mycobacterium leprae DNA from nasal swab among healthy children of East Java, Indonesia
Background: East Java has become one of the provinces that have higher prevalence of leprosy, especially in the coastal region. Environment has also influenced for leprosy transmission and early detection could reduce the incidence rate of new leprosy cases. Epidemiological studies of leprosy in children can give an illustration of the important aspects of the environment. Presence of Mycobacterium leprae (M. leprae) DNA in nasal swabs and seropositivity level among them can describe M. leprae exposure in that area.
Objective: Analyzing PCR from nasal swab and seropositivity level among elementary school children between northern coast and southern coast of East Java province.
Methods: Five hundred and thirty children in Pacitan and Lamongan were involved. Both areas are representation of northern and southern coastal region in East Java Province. After clinical examination, nasal swab and blood samples were obtained. ELISA test was performed to measure the titer of IgM anti Phenolic Glicolipid-1 (PGL-1) antibody then continued by PCR to detect M. leprae DNA.
Results: From 301 students in Pacitan, 25 students (8.3%) are sero-positives and 9 students (2.9%) are PCR positives. from 229 students in Lamongan, 110 (48,3%) students are sero-positives and 49 students (21.4%) are PCR positives. Both are analyzed by Chi-Square, and from the PCR and ELISA, it concluded that there are statistically significant differences between the two regions.
Conclusion: From study above shows that in the northern coast of East Java, incidence of subclinical leprosy is still high, it means that in this area still has a high risk of new cases of leprosy in the future and early detection tools need to performed as a preventative measure.
Optimized broad-range real-time PCR-based method for bacterial screening of platelet concentrates
Bacterial contamination of blood components remains a major challenge in transfusion medicine, particularly, platelet concentrates (PCs) due to the storage conditions that support bacterial proliferation. In this study, we develop a rapid, sensitive and specific real-time PCR protocol for bacterial screening of PCs. An internally controlled real-time PCR-based method was optimized and validated with our proprietary 16S Universal PCR Master Mix (IBMP/Fiocruz), which targets a conserved region of the bacterial 16S rRNA gene. Nonspecific background DNA was completely eliminated by treating the PCR Master Mix with ethidium monoazide (EMA).
A lower limit of detection was observed for 10 genome equivalents with an observed Ct value of 34±1.07 in calibration curve generated with 10-fold serial dilutions of E. coli DNA. The turnaround time for processing, including microbial DNA purification, was approximately 4 hours. The developed method showed a high sensitivity with no non-specific amplification and a lower time-to-detection than traditional microbiological methods, demonstrating it to be an efficient means of screening pre-transfusion PCs.
Evaluation of sample pooling for diagnosis of COVID-19 by Real time PCR– A resource saving combat strategy
Background& objectives: Although about 80% of COVID-19 cases are reported to be mild, the remaining 20% of cases often result in a severe disease with the potential of crushing already overstrained health care services. There has been sustainable growth of COVID-19 cases worldwide since mid-May 2020. In order to keep tabs on community transmission of COVID-19 infection screening of the samples from large population is needed which includes asymptomatic/symptomatic individuals along with migrant population. This requires extra resources, man power and time for detection of SARS-CoV-2by RT-PCR. In current scenario pooled sample testingstrategy advocated by ICMR, New Delhiis a new approach which is very promising in resource limited settings. In this study we have evaluated pooled strategy in terms of accurate testing results, utilization of consumables and identification of border line positive cases.
Materials & methods: Between April-June 2020 we performed COVID-19 testing by RTPCR from areas with varying prevalence of population referred to COVID laboratory, Dr RMLIMS, Lucknow. In a first step the samples are collated into pools of 5 or 10.These pools are tested by RT-PCR. Negative Pools were reported as negative whereas positive pools of 5 and 10 are then deconvoluted and each sample is tested individually.
Results: In the present study, we tested 4620 samples in 462 pools of 10 and 14940 samples in 2990 pools of 5. Among 10 samples pool 61 (13%) pools flagged positive in first step. In second step among 61 pools (610 samples) deconvoluted strategy was followed in which 72 individual samples came positive. Pooled-sample testing strategy helps saves substantial resources and time during surge testing and enhanced pandemic surveillance. This approach requires around 76% to 93% less tests done in low to moderate prevalence settings and group sizes up to 5-10 in a population, compared to individual testing.
Conclusions: Pooled-sample PCR analysis strategies can save substantial resources and time for COVID-19 mass testing in comparison to individual testing without compromising the result outcome of test. In particular, pooled-sample approach can facilitate mass screening in early coming stages of COVID-19 outbreaks, especially in low- and middle-income settings and control the spread by meticulous testing of all risk groups. This article is protected by copyright. All rights reserved.
