Serum and cerebrospinal fluid concentrations of rifampicin at two dose levels in children with tuberculous meningitis.

Twenty patients of tuberculous meningitis (TBM) in age group of 6 months to 10 years included in the study were divided into two groups of 10 patients each. Rifampicin was administered in dosage of 10 mg and 7.5 mg/kg bw to each patient of groups I and II respectively. Drug concentrations in serum and CSF of these patients were measured by a microbiological tube dilution method using a strain of Sarcina lutea. In group I mean serum and CSF concentration was 3.84 micrograms/ml and 0.178 microgram/ml respectively, while in group II it was 2.16 micrograms/ml and 0.206 microgram/ml respectively. These concentrations were many times higher than the MIC against Mycobacterium tuberculosis. Mean percentage penetration of rifampicin in CSF was 5 and 10% in group I and II respectively. We recommend similar studies in large number of children before advocating the therapy with low dose of rifampicin in TBM.

Detection of IgM antibodies in pulmonary tuberculosis by ELISA using A60 antigen.

An enzyme immunosorbent assay (ELISA) was evaluated as a serodiagnostic test in patients with active tuberculosis (Group I), clinically suspected pulmonary tuberculosis (Group II) and pulmonary diseases other than tuberculosis and normal healthy subjects (Group III). and compared with culture and sputum smear examination results. ELISA was found to have a sensitivity of 77.5% and a specificity of 87.5%. Sputum smear had a sensitivity of 65% and specificity of 100%. In patients clinically suspected to have pulmonary tuberculosis ELISA had a sensitivity of 60%. Thus ELISA using A60 antigen can facilitate the diagnosis of tuberculosis in patients with active as well as suspected pulmonary tuberculosis and can provide results within hours of receipt of samples.

Initial and acquired drug resistance of Mycobacterium tuberculosis in east Delhi.

One hundred and fifty six strains of Mycobacterium tuberculosis, isolated from cases of pulmonary tuberculosis were subjected to sensitivity test to detect initial and acquired drug resistance to Streptomycin, isoniazid, Rifampicin, Ethambutol and Pyrazinamide. Initial and acquired drug resistance was observed to one or more drugs in 16% and 24.4% of the patients respectively. Strains resistant to Rifampicin and Ethambutol were resistant to Isoniazid also. Drug resistance was unrelated to age and sex of the patients.

Plasmid profile analysis of Salmonella ser. Typhimurium phage untypable strains encountered in diverse geographic regions of India.

Plasmid profile analysis and antibiotic resistance pattern determination were carried out for 117 phage untypable S. Typhimurium strains. Majority of the strains (82%) were resistant to all the seven antibiotics tested, R-pattern being ApCmKmSmSuTcTp, rest (12%) showed heterogenous R-patterns. Plasmid DNA analysis revealed phage untypable strains to harbour large (58.8-114.3 MDal), intermediate size (36 MDal, 42 MDal) and small (1.8-5.2 MDal) plasmids with varying molecular weights. All the phage untypable strains could be subgrouped by plasmid profile analysis into 23 plasmid patterns. Plasmid profile analysis could discriminate large number of phage untypable strains on the basis of their plasmid pattern.

Plasmid profiles, adhesive & invasive properties of Salmonella ser. Typhimurium strains: phage types 99 & 36.

Adhesive and invasive properties were compared with plasmid profile in S. Typhimurium strains of phage type 99(10) and 36(10). All strains of phage type 99 were multiple drug resistant (ApCmKmSmSuTcTp) and harboured small plasmids of 2.4-5.2 MDal. Six strains of the phage type 36 had ApCmTc R-pattern and two with only ampicillin resistance, carried plasmids of molecular size 2.6-5.2 MDal; two strains were sensitive to all antibiotics and devoid of plasmids. None of the strains were found to harbour high molecular weight plasmids. All plasmid positive strains of phage types 99 and 36 could be divided into two groups of three plasmid patterns each, which were phage type specific. All plasmid positive and negative strains adhered and invaded HeLa cells to different degrees. No correlation could be established between plasmid profile and adhesion invasion characteristics. High molecular weight plasmids therefore are unlikely to be essential for adhesion and invasion.

Cellulose acetate precipitation test in sero-diagnosis of amoebiasis.

Cellulose acetate precipitation (CAP) test for the detection of antibody against Entamoeba histolytica using the axenic antigen, was performed on the 127 serum samples obtained from patients with amoebic liver abscess (14), amoebic hepatitis (21), amoebic dysentry (11), amoebic colitis (31), other parasitic infestations (25) and normal individuals (25). The percent positivity was 100, 95.23, 90.9, 67.74 and 16 and 12 respectively whereas the corresponding figures for the indirect immunoflourescence (IFAT) test were 100, 100, 100, 74.19, 12 and 8 respectively. Although CAP is not as good a test as IFAT, yet it can be recommended for routine testing due to its sensitivity, speed of performance and applicability to a single serum sample.

Immunodiagnosis of amoebiasis.

Serological studies were done on 127 cases using three different techniques namely indirect haemagglutination (IHA), indirect fluorescent antibody test (IFT) and counter immunoelectrophoresis (CIEP) to detect antiamoebic antibodies. All amoebic liver abscess cases showed significant titre of antibodies by all the three tests used. In the group of patients suffering from amoebic pathology of liver, 90.47 per cent were positive by IHA, 100 per cent by IFT and 85.71 per cent by CIEP respectively. Among amoebic dysentry and amoebic colitis cases 81.81 per cent and 80.64 per cent respectively were positive by IHA. The corresponding figures for IFT were 100 per cent and 74.19 per cent and for CIEP 90.90 per cent and 64.51 per cent respectively. Follow up study showed no significant fall in antibody titre in nine cases studied upto 10 weeks after treatment. Amoebic antigen could be detected in pus from all the nine cases with amoebic liver abscess by CIEP test.