A. Chandramuki

Correlation of tumor necrosis factor levels in the serum and cerebrospinal fluid with clinical outcome in Japanese encephalitis patients.

To investigate the prognostic role of tumour necrosis factor (TNF) in Japanese encephalitis virus (JEV) infection, we measured the immunoreactive forms of TNF concentrations in the serum and cerebrospinal fluid (CSF) of 47 laboratory‐confirmed cases of JE. It was observed that TNF levels were elevated (>15 pgm/ml) in all the 47 serum samples (range 19.4–923.8 pg/ml), while in 46/47 CSF samples TNF was elevated (range 10.8–376 pg/ml). The mean (SD) TNF levels in the serum of fatal cases was 234.34 pg/ml (304.40) as compared to the mean of 85.31 pg/ml (SD 153.92) in nonfatal cases. Similar observations were also made with respect to the TNF levels in the CSF; the mean of fatal cases was 69.39 pg/ml (SD 39.00) in contrast to the mean of 62.41 pg/ml (SD 75.25) of nonfatal cases. The increase in TNF levels did not show any correlation to the duration of illness. It was further observed that the mortality rate increased with increasing concentrations of TNF in the serum and CSF. Correlation of laboratory parameters to final outcome revealed that TNF concentrations above 50 pg/ml in serum correlated significantly (P = .05) with a fatal outcome, whilst high levels of JEV‐IgM antibodies (>500 units) in the CSF correlated with a nonfatal outcome (P = .03). These results suggest that TNF can be used as a possible prognosticator of a fatal outcome in JEV infection. J Med Virol 51:132–136, 1997.

Japanese encephalitis virus antigen in the human brain and its topographic distribution

This study reports the pathological findings and the distribution of viral antigen in the brains of 13 confirmed and autopsied cases of Japanese encephalitis (JE) in correlation with other virus-specific immunological parameters measured in the cerebrospinal fluid (CSF) antemortem. Japanese encephalitis virus (JEV)-specific antibodies were detected in the CSF of 10 of 13 patients, JEV antigen was detected in the CSF of 7 of 13 and JEV-specific immune complexes were detected in the CSF of 3 of 11 patients. Viral antigen was localised immunocytochemically in the brain tissue of 11 of 13 cases, indicating, that viral antigen could not be cleared from the tissues by the antibody. The topographic distribution of the tissue-associated antigen in the thalamus, hippocampus, substantia nigra and medulla oblongata explain the evolution of post JE sequelae.

BACTERIOLOGICAL PROFILE OF COMMUNITY ACQUIRED ACUTE BACTERIAL MENINGITIS: A TEN-YEAR RETROSPECTIVE STUDY IN A TERTIARY NEUROCARE CENTRE IN SOUTH INDIA

PURPOSE Ten years retrospective study to evaluate the bacteriological spectrum of community acquired acute bacterial meningitis (CAABM). METHODS Cerebrospinal fluid (CSF) samples from 385 clinically suspected cases of pyogenic meningitis were processed for cell counts, cytospin Gram stain, culture, antigen detection by latex agglutination (LAT) and antibiotic susceptibility test. Eighteen of these CSF samples were also subjected to a polymerase chain reaction (PCR) assay for detection of pneumococcal DNA. RESULTS The etiological agent could be identified in 284 (73.8%) of the total 385 cases by culture and/or smear and /or LAT. Streptococcus pneumoniae was the predominant pathogen accounting for 238 (61.8%) cases. Haemophilus influenzae and Neisseria meningitidis accounted for 7 (1.8%) and 4 (1%) cases respectively. Other gram negative bacilli, Streptococcus spp. and Staphylococcus aureus were isolated from 19 (4.9%), 9 (2.3%) and 7 (1.8%) cases respectively. CONCLUSIONS Streptococcus pneumoniae remains the major aetiological agent of CAABM both in adults and children in our set-up. No penicillin resistance was detected among the isolates. Further research should focus on preventable aspects of CAABM, especially pneumococcal vaccines, to help reduce the disease burden.

Cryptococcal infections of the central nervous system : an analysis of predisposing factors, laboratory findings and outcome in patients from South India with special reference to HIV infection

The incidence of cryptococcosis in patients with AIDS is significant. Predisposing factors, laboratory findings and outcome were assessed in 60 patients with cryptococcal infections of the central nervous system over a 17.5-year period (Jan. 1978-June 1995). Predisposing factors for cryptococcal infection were identified in 36 patients, with HIV infection being the commonest (18). Cryptococcal cultures were positive in all patients. India ink staining was positive in 48 patients and cryptococcal antigen was detected in 35 of 36 patients tested. Comparison of clinical and laboratory parameters between HIV-positive and HIV-negative patients showed that CSF cell response was poorer, culture of cryptococci from non-neural sites was more frequent and mortality was higher in the HIV-positive group. Although not statistically significant, concurrent systemic infections, especially tuberculosis, were more frequent in the HIV-positive group.

Rapid diagnosis of tuberculous meningitis: A comparative evaluation of in-house PCR assays involving three mycobacterial DNA sequences, IS6110, MPB-64 and 65 kDa antigen

A PCR was standardized for amplifying three different mycobacterial--IS6110, MPB-64, 65 kDa DNA sequences. A comparative evaluation of the three PCR assays was carried out for the rapid diagnosis of tuberculous meningitis (TBM) using cerebrospinal fluid (CSF) specimens. While the IS6110 PCR was a single-step amplification reaction, the MPB-64 and 65 kDa antigen PCR assays were nested reactions. A total of 176 cerebrospinal fluid (CSF) samples from 176 patients were subjected to amplification of the three different mycobacterial sequences. Amongst them, 45 samples were obtained from confirmed cases of TBM (culture positive) and 56 samples were obtained from clinically suspected cases of TBM which were culture-negative. The remaining 75 CSF samples were categorized under the non-infectious and infectious illness of the central nervous system (CNS). Against a gold standard of culture, a sensitivity of 98% (NPV=99%) and a specificity of 100% (PPV=100%) was observed with the IS6110 PCR. Among the nested PCRs, a sensitivity of 91% (NPV=94%) and a specificity of 91% (PPV=85%) was observed with the MPB-64 assay, while the 65 kDa protocol had an associated sensitivity of 51% (NPV=76%) and a specificity of 92% (PPV=79%). These findings suggest that among the nested PCR assays, the MPB-64 PCR assay was associated with an enhanced degree of sensitivity and was comparable in terms of specificity. Our study also demonstrates that the IS6110 assay, while being a single-step PCR had the advantage of being a rapid test for the diagnosis of TBM, with increased sensitivity and enhanced specificity as compared to the nested PCR protocols.

Cryptococcus gattii serotype-C strains isolated in Bangalore, Karnataka, India

During a retrospective study on cryptococcosis carried out in Bangalore, Karnataka, India, four Cryptococcus gattii strains were isolated from one HIV‐positive and three HIV‐negative patients, two of which had unknown predisposing conditions. Serotyping and genotyping showed that the isolates were C. gattii serotype C, mating‐type α and genotype VGIV. All the isolates were identical by multilocus sequence typing, but presented a low similarity compared with a set of 17 C. gattii global control strains. The comparison with a larger number of previously reported C. gattii strains, including African isolates, revealed a close relationship between Indian and African serotype‐C isolates.

Comparative evaluation of BACTEC 460TB system and Lowenstein-Jensen medium for the isolation of M. tuberculosis from cerebrospinal fluid samples of tuberculous meningitis patients.

PURPOSE To evaluate the role of the radiometric BACTEC 460TB system and the conventional Lowenstein-Jensen (LJ) medium for isolation of M. tuberculosis from cerebrospinal fluid (CSF) samples of tuberculous meningitis (TBM) patients. METHODS CSF specimens (n=2325) from suspected TBM patients were processed for isolation of mycobacteria by inoculating BACTEC 12B medium and the LJ medium. The isolation of mycobacteria in both media was confirmed by microscopy and biochemical identification. Drug sensitivity testing for the anti-TB drugs was carried out by BACTEC radiometric method. RESULTS Among the total 2325 CSF specimens processed by both methods, M. tuberculosis was isolated from 256 specimens. The isolation rates were 93% and 39% for the BACTEC system and LJ medium respectively. Both the media supported growth in 32% of the culture-positive specimens. BACTEC system alone yielded growth in 61% and LJ alone in 7%, of the culture-positive specimens. Among 205 isolates tested for drug susceptibility 81% were sensitive to all the drugs tested and 19% were resistant. CONCLUSIONS The BACTEC 460TB system provides a highly sensitive and rapid tool for the isolation and drug susceptibility testing of M. tuberculosis, from CSF of TBM patients. Use of a solid medium in conjunction with the BACTEC 12B medium is essential for optimal recovery for M. tuberculosis from CSF specimens.

Detection of Antibody to Mycobacterium tuberculosis Protein Antigens in the Cerebrospinal Fluid of Patients with Tuberculous Meningitis

Antibodies against Mycobacterium tuberculosis antigens were detected by enzyme-linked immunosorbent assay in cerebrospinal fluid (CSF) samples obtained from 442 patients with tuberculous meningitis (TBM) and 102 control patients. Antibodies were found in the CSF of 87% of patients with clinical (culture-negative) TBM, 72% of patients with culture-positive TBM, and 65% of patients with autopsy-proven TBM. That anti-M. tuberculosis antibodies were detected in the CSF of patients with clinically diagnosed cases more frequently than in patients with culture-positive cases suggests that the detection of antibodies in CSF tends to decrease as bacillary load increases. Of the patients with clinical TBM who were coinfected with human immunodeficiency virus (HIV), 70% exhibited anti-M. tuberculosis antibody in CSF, which suggests that antibody responses in this group were substantially weaker than those in HIV-negative patients with clinical TBM. Some groups showed a stronger response to certain antigens, which suggests that antigen recognition patterns may be specific for the stage of disease.

Cerebral phaeohyphomycosis caused by Scytalidium dimidiatum: a case report from India

We report a case of cerebral phaeohyphomycosis caused by Scytalidium dimidiatum (synanamorph Nattrassia mangiferae) in a young, apparently immunocompetent Indian male. Etiological diagnosis was made by recovery of the fungus in culture and histopathological examination. The infection proved fatal despite aggressive antifungal therapy.

Detection of autoantibodies to neural antigens in the CSF of Japanese encephalitis patients and correlation of findings with the outcome

This study reports the detection of autoantibodies to myelin basic protein (MBP) and neurofilament proteins (NFP) in serum and cerebrospinal fluid (CSF) of Japanese encephalitis patients. The diagnosis of Japanese encephalitis was confirmed in 72 patients by the presence of virus specific antibodies to JEV in the CSF (28/72), viral antigen in the CSF (19/72) and simultaneous presence of both antigen and JEV antibodies in the CSF in 25/72 patients. Autoantibodies to either purified NFP (10) or MBP (8) or both (17) were detected in the CSF of 35 patients by ELISA in contrast with the control CSF samples. Amongst them 20 had similar antibodies in the serum as well. Correlation of immunological findings with the clinical outcome revealed that the presence of autoantibodies in the CSF especially to NFP was associated with a fatal outcome (P < 0.05).