Early diagnosis of tuberculous meningitis by an indirect ELISA protocol based on the detection of the antigen ESAT-6 in cerebrospinal fluid

The Diagnostic Value of Urinary Secretory Antigen Target of 6 kDa in Childhood Pulmonary Tuberculosis

Introduction. Childhood tuberculosis (TB) is difficult to diagnosed and is  based together on  clinical and microbiology examinations. Since in children  signs and symptoms of TB are not typical and sputum is  difficult to be obtained,  Mycobacterium tuberculosis (Mtb) antigen detection  could  be considered  as a non invasive method for early detection of childhood TB. ESAT-6 is a low molecular weight specific protein that plays an important role in Mtb virulence. Aim. To determine the diagnostic value of urinary ESAT-6 for the diagnosis of childhood tuberculosis. Methodology.This was a cross-sectional study, with consecutive sampling collection . in children aging between  0-14 years suspected for pulmonary TB based on the clinical presence of  :cough lasting  more than 2 weeks, fever without clear ethiology, loss of body weight or poor weight gain, fatigue, malaise with positive history of contact with sputum smear from adult TB patients. Diagnosis of pulmonary TB was based on clinical presentation plus tuberculin positive skin test, chest x-ray, AFB staining and/or sputum culture. Subjects who met the inclusion criteria but unconfirmed by clinical and microbiological were considered as control (non-TB group). Urinary ESAT-6 level was analyzed by using ELISA. Cut off value and AUC was determined using ROC Statistical Analysis (SPSS 20.0). Sensitivity and specificity was measured from 2x2 crosstable. Result. Between the 61 studied children with suspected TB, 46/61 (75%) were finally diagnosed with TB, with 34/46 (74%) microbiologically confirmed cases either by sputum microscopy 31/34 (91%) or culture 3/34 (9%), whereas 15/61 (25%) subjects were not-confirmed cases (non-TB group). The mean value of urinary ESAT-6 level was higher in TB than non-TB group, Mean (SD) [4.855(6.714)] ng/mLvs [1.503(0.946)] ng/mL; p=<0.001(Mann-Whitney test). At ROC curve analysis ,the cut off value of urinary ESAT-6 in subjects TB  confirmed both with clinical plus microbiology evaluation  as reference standard was 1,91 ng/mL, with sensitivity 72% and specificity 67%. While the cut off value of ESAT-6 in TB subjects confirmed group only by clinical signs was 2.45 ng/mL, with sensitivity 65% and specificity 67%. Conclusion. For  TB Diagnosis in Children, Urinary ESAT-6 urine could be considered  of   value  when  utilized in addition to microbiological tests and clinical examination.

Advances in tuberculous meningitis diagnosis

Introduction: Tuberculous meningitis (TBM) is the most devastating form of central nervous system tuberculosis (TB) and causes high mortality worldwide. Nonspecific clinical manifestations and limited sensitivity of existing laboratory methods make the diagnosis elusive due to the paucibacillary nature of the infection. Areas Covered: We reviewed current literature on the adequacy and limitations of globally existing laboratory methods for diagnosing TBM. Expert opinion: TBM is deadliest among all TB forms, as the outcome may lead to death in 50% of cases, and survivors undergo irreversible neurological disorders. Therefore, early diagnosis and prompt treatment are cornerstones of effective disease management. Conventional microscopy and culture are widely used modalities but remain inadequate in most TBM cases. Although expanded use of rapid molecular tests such as real-time PCR and Xpert Ultra, even in resource-limited settings, hold promising results for TB diagnosis but need optimization for early detection of TBM. Moreover, CSF IGRA is also used but unable to differentiate between active and latent TB. Overall no single test for diagnosing TBM has adequate accuracy so, there is an urgent need to devise a point-of-care test.

Xpert MTB/RIF Ultra for the Diagnosis of Tuberculous Meningitis: A Small Step Forward

The delayed diagnosis of tuberculous meningitis (TBM) leads to poor outcomes, yet the current diagnostic methods for identifying Mycobacterium tuberculosis in cerebrospinal fluid (CSF) are inadequate. The first comparative study of the new GeneXpert MTB/RIF Ultra (Xpert Ultra) for TBM diagnosis suggested increased sensitivity of Xpert Ultra. Two subsequent studies have shown Xpert Ultra has improved sensitivity, but has insufficient negative predictive value to exclude TBM. Collecting and processing large volumes of CSF for mycobacterial testing are important for optimal diagnostic test performance. But clinical, radiological, and laboratory parameters remain essential for TBM diagnosis and empiric therapy is often needed. We therefore caution against the use of Xpert Ultra as a single diagnostic test for TBM; it cannot be used to "rule out" TBM.

Role of Immuno-Polymerase Chain Reaction (I-PCR) in Resolving Diagnostic Dilemma Between Tuberculoma and Neurocysticercosis: A Case Report

BACKGROUND Tuberculoma and neurocysticercosis (NCC) often show similar clinical and neuroimaging features. Differential diagnosis of these 2 diseases is imperative, as tuberculoma is an active infection that requires immediate anti-tubercular therapy (ATT). CASE REPORT We present the case of a 17-year-old Indian girl with fever, severe headache, and right 6th cranial nerve palsy. Brain magnetic resonance imaging (MRI) showed multiple tiny ring-enhancing lesions in bilateral cerebral parenchyma with mild perilesional edema, which were initially thought to be NCC, but subsequently were diagnosed as brain tuberculomas. Based on clinical findings, mildly increased choline/creatine ratio (1.35) with slight prominent lipid lactate peak and absence of alanine, succinate peak by magnetic resonance spectroscopy (MRS), and the detection of Mycobacterium tuberculosis (Mtb)-specific early-secreted antigenic target-6 (ESAT-6, Rv3875) protein from the cerebrospinal fluid (CSF) by indirect ELISA, as well as indirect immuno-PCR (I-PCR) assay, diagnosis of brain tuberculomas associated with tuberculous meningitis (TBM) was confirmed, which was followed by ATT. The patient responded well and the symptoms resolved. CONCLUSIONS In this case, multiple ring-enhancing lesions of the brain by MRI were diagnosed as tuberculomas associated with TBM by MRS and indirect ELISA/I-PCR method, thus resolving the diagnostic dilemma.

Comparison of the Performance of Urinary Mycobacterium tuberculosis Antigens Cocktail (ESAT6, CFP10, and MPT64) with Culture and Microscopy in Pulmonary Tuberculosis Patients

Pulmonary tuberculosis (TB) is a major global health problem and is one of the top 10 causes of death worldwide. Our study aimed to evaluate the performance of urinary Mycobacterium tuberculosis (Mtb) antigens cocktail (ESAT6, CFP10, and MPT64) compared with culture and microscopy. This descriptive cross-sectional study was conducted in Dr. Hasan Sadikin General Hospital, Bandung, from January 2014 to October 2016. A total of 141 pulmonary tuberculosis patients were included. Sputum samples were examined for acid-fast bacilli (ZN stain) and mycobacterial culture (LJ); the Mtb antigens cocktail was examined in the urine sample. The positivity rate of TB detection from the three methods was as follows: AFB 52/141 (36.9%), culture 50/141 (35.5%), and urinary Mtb antigens cocktail 95/141 (67.4%). Sensitivity, specificity, PPV, and NPV of urinary Mtb antigens cocktail were 68.2%, 33%, 31.6%, and 69.6%, respectively. Validity of combination of both methods with culture as a gold standard yielded sensitivity, specificity, PPV, and NPV of 90%, 28.6%, 40.9%, and 83.8%, respectively. Combination of urinary Mtb antigens cocktail with AFB as a screening test gives a good sensitivity, although the specificity is reduced. Urinary Mtb antigens cocktail can be used as screening test for pulmonary tuberculosis.

Biomarkers of Cerebral Injury and Inflammation in Pediatric Tuberculous Meningitis

Background

Tuberculous meningitis (TBM) leads to death or disability in half the affected individuals. Tools to assess severity and predict outcome are lacking. Neurospecific biomarkers could serve as markers of the severity and evolution of brain injury, but have not been widely explored in TBM. We examined biomarkers of neurological injury (neuromarkers) and inflammation in pediatric TBM and their association with outcome.

Methods

Blood and cerebrospinal fluid (CSF) of children with TBM and hydrocephalus taken on admission and over 3 weeks were analyzed for the neuromarkers S100B, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP), in addition to multiple inflammatory markers. Results were compared with 2 control groups: patients with (1) a fatty filum (abnormal filum terminale of the spinal cord); and (2) pulmonary tuberculosis (PTB). Imaging was conducted on admission and at 3 weeks. Outcome was assessed at 6 months.

Results

Data were collected from 44 patients with TBM (cases; median age, 3.3 [min-max 0.3-13.1] years), 11 fatty filum controls (median age, 2.8 [min-max 0.8-8] years) and 9 PTB controls (median age, 3.7 [min-max 1.3-11.8] years). Seven cases (16%) died and 16 (36%) had disabilities. Neuromarkers and inflammatory markers were elevated in CSF on admission and for up to 3 weeks, but not in serum. Initial and highest concentrations in week 1 of S100B and NSE were associated with poor outcome, as were highest concentration overall and an increasing profile over time in S100B, NSE, and GFAP. Combined neuromarker concentrations increased over time in patients who died, whereas inflammatory markers decreased. Cerebral infarcts were associated with highest overall neuromarker concentrations and an increasing profile over time. Tuberculomas were associated with elevated interleukin (IL) 12p40, interferon-inducible protein 10, and monocyte chemoattractant protein 1 concentrations, whereas infarcts were associated with elevated tumor necrosis factor α, macrophage inflammatory protein 1α, IL-6, and IL-8.

Conclusions

CSF neuromarkers are promising biomarkers of injury severity and are predictive of mortality. An increasing trend suggested ongoing brain injury, even though markers of inflammation declined with treatment. These findings could offer novel insight into the pathophysiology of TBM.

Thermotropic liquid crystal films for biosensors and beyond

Recent results on structural properties and possible bio-sensing applications of planar liquid crystal films are reviewed.

Laboratory Diagnosis of Central Nervous System Infection

Central nervous system (CNS) infections are potentially life threatening if not diagnosed and treated early. The initial clinical presentations of many CNS infections are non-specific, making a definitive etiologic diagnosis challenging. Nucleic acid in vitro amplification-based molecular methods are increasingly being applied for routine microbial detection. These methods are a vast improvement over conventional techniques with the advantage of rapid turnaround and higher sensitivity and specificity. Additionally, molecular methods performed on cerebrospinal fluid samples are considered the new gold standard for diagnosis of CNS infection caused by pathogens, which are otherwise difficult to detect. Commercial diagnostic platforms offer various monoplex and multiplex PCR assays for convenient testing of targets that cause similar clinical illness. Pan-omic molecular platforms possess potential for use in this area. Although molecular methods are predicted to be widely used in diagnosing and monitoring CNS infections, results generated by these methods need to be carefully interpreted in combination with clinical findings. This review summarizes the currently available armamentarium of molecular assays for diagnosis of central nervous system infections, their application, and future approaches.

Detection of pandemic strain of influenza virus (A/H1N1/pdm09) in pigs, West Africa: implications and considerations for prevention of future influenza pandemics at the source

Background

Human and animal influenza are inextricably linked. In particular, the pig is uniquely important as a mixing vessel for genetic reassortment of influenza viruses, leading to emergence of novel strains which may cause human pandemics. Significant reduction in transmission of influenza viruses from humans, and other animals, to swine may therefore be crucial for preventing future influenza pandemics. This study investigated the presence of the 2009 pandemic influenza A/H1N1 virus, A(H1N1)pdm09, in Nigerian and Ghanaian pigs, and also determined levels of acceptance of preventive measures which could significantly reduce the transmission of this virus from humans to pigs.

Methods

Nasal swab specimens from 125 pigs in Ibadan, Nigeria, and Kumasi, Ghana, were tested for the presence of influenza A/California/04/2009 (H1N1) by quantitative antigen-detection ELISA. A semi-structured questionnaire was also administered to pig handlers in the two study areas and responses were analyzed to evaluate their compliance with seven measures for preventing human-to-swine transmission of influenza viruses.

Results

The virus was detected among pigs in the two cities, with prevalence of 8% in Ibadan and 10% in Kumasi. Levels of compliance of pig handlers with relevant preventive measures were also found to be mostly below 25 and 40% in Ibadan and Kumasi, respectively.

Conclusion

Detection of influenza A(H1N1)pdm09 among pigs tested suggests the possibility of human-to-swine transmission, which may proceed even more rapidly, considering the very poor acceptance of basic preventive measures observed in this study. This is also the first report on detection of influenza A(H1N1)pdm09 in Ghanaian pigs. We recommend improvement on personal hygiene among pig handlers, enforcement of sick leave particularly during the first few days of influenza-like illnesses, and training of pig handlers on recognition of influenza-like signs in humans and pigs. These could be crucial for prevention of future influenza pandemics.

Roles of mycobacterium tuberculosis ESAT-6 in the development of renal injury

OBJECTIVE

The present study was designed to evaluate the role of mycobacterium tuberculosis early secretory antigen target-6 (MtbESAT-6) in the development of renal injury.

METHODS

PET42a (+) ESAT6 prokaryotic expression plasmid was constructed and the purified ESAT6 protein without endotoxin was obtained. Sixty healthy, clean, male Kunming mice were randomly divided into two groups: the experimental group (n = 30) and the control group (n = 30). Each mouse in the experimental group were injected with 0.5 ml ESAT-6 protein, and each mouse in the control group were injected with 0.5 ml sterile saline on the tail vein. Blood, urine and kidney tissues were collected. Serum creatinine (Scr), blood urea nitrogen (BUN), and urinary creatinine (Cr) were determined by HITACHI 7150 automatic biochemical analyzer and creatinine clearance rate (Ccr) was calculated. Renal tissues were conducted for hematoxylin-eosin (HE) staining and pathological scores of renal injury were recorded under the light microscope.

RESULTS

Using MTB H37Ra strains genome DNA as template, the ESAT6 gene amplified by Hieff Pfu DNA Polymerase using polymerase chain reaction (PCR) technique was consistent with the expected size. PET42a (+) ESAT6 vector plasmid was successfully obtained and ESAT6 recombinant protein was successfully expressed with the protein concentration of 1.69 mg/ml. BUN and Scr in the experimental group were gradually increased, Ccr was gradually decreased, and the pathological score of renal injury increased gradually, and all of which were significantly higher than that in the control group after the experiment of 12 h, 24 h and 48 h (all P < 0.05).

CONCLUSION

MtbESAT-6 might contribute to the development of renal injury.

Antigenic Detection of Human Strain of Influenza Virus A (H3N2) in Swine Populations at Three Locations in Nigeria and Ghana during the Dry Early Months of 2014

Since the first detection of human H3N2 influenza virus in Taiwanese pigs in 1970, infection of pigs with wholly human viruses has been known to occur in other parts of the world. These viruses, referred to as human-like H3N2 viruses, have been known to cause clinical and subclinical infections of swine populations. Due to the paucity and complete unavailability of information on transmission of influenza viruses from other species, especially humans, to swine in Nigeria and Ghana, respectively, this study was designed to investigate the presence and prevalence of a human strain of influenza A (H3N2) in swine populations at three locations in two cities within these two West African countries in January and February, 2014. Using stratified random technique, nasal swab specimens were collected from seventy-five (75) pigs at two locations in Ibadan, Nigeria and from fifty (50) pigs in Kumasi, Ghana. These specimens were tested directly by a sensitive Quantitative Solid Phase Antigen-detection Sandwich ELISA using anti-A/Brisbane/10/2007 haemagglutinin monoclonal antibody. Influenza virus A/Brisbane/10/2007 (H3N2) was detected among pigs at the three study locations, with an aggregate prevalence of 4.0% for the two locations in Ibadan, Nigeria and also 4.0% for Kumasi, Ghana. Transmission of influenza viruses from other species to swine portends serious sinister prospects for genetic reassortment and evolvement of novel viruses. We therefore recommend that further studies should be carried out to investigate the presence of other circulating human and avian influenza viruses in swine populations in West Africa and also determine the extent of genetic reassortment of strains circulating among these pigs. This would provide an early warning system for detection of novel influenza viruses, which could have pandemic potentials.

pSiM24 is a novel versatile gene expression vector for transient assays as well as stable expression of foreign genes in plants

We have constructed a small and highly efficient binary Ti vector pSiM24 for plant transformation with maximum efficacy. In the pSiM24 vector, the size of the backbone of the early binary vector pKYLXM24 (GenBank Accession No. HM036220; a derivative of pKYLX71) was reduced from 12.8 kb to 7.1 kb. The binary vector pSiM24 is composed of the following genetic elements: left and right T-DNA borders, a modified full-length transcript promoter (M24) of Mirabilis mosaic virus with duplicated enhancer domains, three multiple cloning sites, a 3'rbcsE9 terminator, replication functions for Escherichia coli (ColE1) and Agrobacterium tumefaciens (pRK2-OriV) and the replicase trfA gene, selectable marker genes for kanamycin resistance (nptII) and ampicillin resistance (bla). The pSiM24 plasmid offers a wide selection of cloning sites, high copy numbers in E. coli and a high cloning capacity for easily manipulating different genetic elements. It has been fully tested in transferring transgenes such as green fluorescent protein (GFP) and β-glucuronidase (GUS) both transiently (agro-infiltration, protoplast electroporation and biolistic) and stably in plant systems (Arabidopsis and tobacco) using both agrobacterium-mediated transformation and biolistic procedures. Not only reporter genes, several other introduced genes were also effectively expressed using pSiM24 expression vector. Hence, the pSiM24 vector would be useful for various plant biotechnological applications. In addition, the pSiM24 plasmid can act as a platform for other applications, such as gene expression studies and different promoter expressional analyses.