Utilization of Truenat chips in defining XDR, pre-XDR and MDR in tuberculous meningitis.

SETTING AND OBJECTIVE: To develop and evaluate newer molecular tests that identify drug resistance according to contemporary definitions in Tuberculous meningitis (TBM), the most severe form of EPTB. DESIGN: 93 cerebrospinal fluid (CSF) specimens [41 culture-positive and 52 culture-negative], were subjected to Truenat MTB Plus assay along with chips for rifampicin, isoniazid, fluoroquinolones and bedaquiline resistance. The performance was compared against phenotypic drug susceptibility testing (pDST), Line probe assay (LPA) and gene sequencing. RESULTS: Against pDST, Truenat chips had a sensitivity and specificity of 100%; 94.47%, 100%; 94.47%, 100%; 97.14% and 100%; 100%, respectively for rifampicin, isoniazid, fluoroquinolones and bedaquiline. Against LPA, all Truenat chips detected resistant isolates with 100% sensitivity; but 2 cases each of false-rifampicin and false-isoniazid resistance and 1 case of false-fluoroquinolone resistance was reported. Truenat drug chips gave indeterminate results in ∼25% cases, which were excluded. All cases reported indeterminate were found to be susceptible by pDST/LPA. CONCLUSION: The strategic drug resistance chips of Truenat Plus assay can contribute greatly to TB elimination by providing rapid and reliable detection of drug resistance pattern in TBM. Cases reported indeterminate require confirmation by other phenotypic and genotypic methods.

"Comparative evaluation of different chemical agents induced Autism Spectrum Disorder in experimental Wistar rats".

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition with uncertain etiology and pathophysiology. Several studies revealed that the commonly used animal models like Valproic Acid (VPA) and Propionic Acid (PPA) do not precisely represent the disease as the human patient does. The current study was conducted on different chemically (VPA, PPA, Poly I:C, Dioxin (2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)) & Chlorpyrifos (CPF)) induced ASD-like animal models and validated the best suitable experimental animal model, which would closely resemble with clinical features of the ASD. This validated model might help to explore the pathophysiology of ASD. This study included rat pups prenatally exposed to VPA, PPA, Poly I:C, Dioxin & CPF within GD9 to GD15 doses. The model groups were validated through developmental and behavioral parameters, Gene Expressions, Oxidative Stress, and Pro-inflammatory and Anti-inflammatory cytokines levels. Developmental and neurobehavioral parameters showed significant changes in model groups compared to the control. In oxidative stress parameters and neuro-inflammatory cytokines levels, model groups exhibited high oxidative stress and neuro-inflammation compared to control groups. Gene expression profile of ASD-related genes showed significant downregulation in model groups compared to the control group. Moreover, the Poly I:C group showed more significant results than other model groups. The comparison of available ASD-like experimental animal models showed that the Poly I:C induced model represented the exact pathophysiology of ASD as the human patient does. Poly I:C was reported in the maternal immune system activation via the inflammatory cytokines pathway, altering embryonic development and causing ASD in neonates.

Role of vascular endothelial growth factor in tuberculous meningitis: A prospective study from a tertiary care center in North India.

INTRODUCTION: The status of vascular endothelial-derived growth factor (VEGF) in the pathogenesis of tuberculous meningitis (TBM) remains far from clear. We prospectively evaluated the role of serum and cerebrospinal fluid (CSF) VEGF in TBM. PATIENTS AND METHODS: This prospective study was conducted at a tertiary care center in North India from January 2018 to June 2019. Consecutive drug-naive patients (n = 82) of TBM diagnosed on the basis of modified Ahuja's criteria were included in the study. The results were compared with 49 control subjects (n = 49). Serum and CSF VEGF were done in all the cases and controls. Follow-up serum VEGF levels were done in 34 patients after 3 months of completion of antitubercular therapy. The VEGF levels were estimated using the human VEGF enzyme-linked immunosorbent assay kit. RESULTS: The mean age was 29.9 ± 13.1 years. The study group consisted of 33 (40.2%) men and 49 (59.8%) women. BACTEC MGIT960 was positive in 15 (18%) patients while multiplex tuberculosis polymerase chain reaction was positive in 73 (89%) patients. Levels of VEGF in serum and CSF of TBM patients were not elevated when compared to controls. There was no association between final outcome in TBM and decrease in serum levels of VEGF at follow-up. CONCLUSION: VEGF may not be playing a significant role in the pathogenesis of TBM. Future studies with larger sample size may clarify the status of VEGF further in TBM.

Determining the diagnostic potential of Truenat MTB Plus for Tubercular lymphadenitis and detection of drug resistance and a comparison with GeneXpert Ultra.

SETTING: Tubercular lymphadenitis (TBLA), the most common form of extrapulmonary tuberculosis, is a diagnostic challenge. OBJECTIVE: Truenat MTB Plus (TruPlus) along with Truenat Rif assay (TruRif) was evaluated for detection of TBLA and rifampicin resistance and compared with GeneXpert Ultra (Xpert Ultra). DESIGN: 100 fine-needle aspirated specimens [50 confirmed by culture/smear/cytology, 20 clinically suspected, and 30 controls], processed in the mycobacteriology division of department of microbiology were subjected to TruPlus and TruRif, Xpert Ultra and multiplex PCR. The results of TBLA detection were compared against composite reference standard (CRS) and those of rifampicin resistance were compared against phenotypic drug susceptibility testing and rpoB gene sequencing. RESULTS: In comparison to CRS, the diagnostic yield of TruPlus, Xpert Ultra and MPCR was 77.14%, 59.18% and 84.28%, respectively; with substantial agreement for TruPlus (k = 0.66) and MPCR (k = 0.76) and moderate for Xpert Ultra (k = 0.60). TruRif reported four cases as RifR and Xpert Ultra reported two. On comparing with phenotypic DST and gene sequencing, only two cases of RifR were confirmed, hence TruRif reported false-RifR in two cases. CONCLUSION: TruPlus could be used as a reliable tool for diagnosing TBLA. The reporting of RifR by TruRif should be confirmed by phenotypic DST or gene sequencing.

Molecular diagnosis of Tuberculous meningitis: sdaA-based multi-targeted LAMP and GeneXpert Ultra.

SETTING: Nucleic acid amplification techniques like GeneXpert and GeneXpert Ultra (Xpert Ultra), the first-line tests for diagnosing Tuberculous meningitis (TBM), are expensive and depend on sophisticated equipment. OBJECTIVE: The diagnostic potential of multitargeted loop-mediated isothermal assay (MLAMP), a low-cost simple test using novel gene combination, was evaluated for TBM. DESIGN: 300 CSF specimen (200 TBM patients, 100 controls) processed between January 2017 and December 2021 were subjected to MLAMP (using sdaA, IS1081 and IS6110 gene targets), sdaA PCR and Xpert Ultra. The performance was evaluated against uniform case definition as per Marais criteria, and against culture. RESULTS: Uniform case definition classified 50 as definite TBM and 150 as probable or definite TBM. Against this uniform case definition, the sensitivity and specificity of MLAMP was 88% and 100%, respectively. The sensitivity was 96% against culture-positive cases and 85.3% against culture-negative cases. The sensitivity of sdaA-LAMP, IS1081-LAMP, IS6110-LAMP, Xpert Ultra and sdaA-PCR was 82.5%, 80.5%, 85.3%, 67% and 71%, respectively against uniform case definition. sdaA-LAMP detected additional two cases and IS1081-LAMP detected nine. 11 of 134 (8.2%) cases were reported rifampicin resistant by Xpert Ultra. CONCLUSION: MLAMP, incorporating sdaA and IS1081, is a cheap, easy and accurate first-line diagnostic test for TBM.

Neurological manifestations of scrub typhus: encephalitis and Guillain-Barré syndrome (GBS).

Scrub typhus is a tropical febrile illness that mainly affects rural populations in tropical and subtropical countries. It can range in severity from a mild febrile illness to multisystem involvement. Systemic dysfunction often appears in the second week of sickness, and hepatic, renal and brain involvement are well documented. Although encephalitis is the most frequent neurological ailment, a wide range of unusual complications involving the central and peripheral nervous systems have been identified-however, concomitant multiaxial involvement of the central and peripheral nervous systems is unique. We report a case of a young man with serologically confirmed scrub typhus presenting with fever, eschar, altered sensorium and progressive quadriplegia with hyporeflexic deep tendon reflexes. MRI revealed changes suggestive of encephalitis, and there was evidence of axonopathy on nerve conduction studies. A diagnosis of scrub typhus encephalitis with concomitant Guillain-Barré syndrome was made. He received doxycycline and intravenous immunoglobulin therapy, in addition to supportive treatment.