Clinical utility of Polymerase Chain Reaction for improved diagnosis of Pulmonary Tuberculosis in children.

Background: Conventional bacteriological methods rarely detect M. tuberculosis in clinical samples from children and, hence are of limited use in the diagnosis of active tuberculosis in them. There is need for an alternative detection method which is rapid, specific and sensitive. Aim: The efficacy of Polymerase Chain Reaction (PCR) was evaluated in the diagnosis of pulmonary tuberculosis in children. Methods: Sixty two (62) hospitalized children were included in the study. Thirty-one were suffering from active tuberculosis, 11 children had tuberculous infection but no active disease and 20 children had other unrelated diagnosis. Early morning gastric aspirates and sputum samples were processed using conventional techniques of mycobacterial isolation and PCR for M. tuberculosis complex specific MPB64 gene. Favorable response to anti- tubercular treatment (ATT) was taken as the gold standard. Results: In the active tuberculosis group 12 out 31 children were positive by PCR while microscopy and culture were positive in 3 and 6 children respectively. All samples positive by microscopy and culture were positive by PCR giving a sensitivity of 100% for culture confirmed cases. Conclusion: Benefit of rapid and reliable results with PCR offers an appreciable advantage over traditional techniques when used in conjunction with clinical profile and epidemiological factors such as age, socio-economic and nutritional status, contact history and any other intercurrent illness.

Diagnostic utility of ELISA test using antigen A60 in suspected cases of tuberculous meningitis in paediatric age group.

The aim of the study was evaluation of the utility of ELISA test using antigen A60 for rapid diagnosis of tuberculous menigitis (TBM) in paediatric age group. ELISA test based on mycrobacterial antigen A60 (Anda biological, France) was used to estimate specific IgM and IgG antibodies in the sera and CSF of 20 suspected cases of TBM which were selected on the basis of numerous parameters and were smear negative on concentrated smear of CSF. Sera of 20 Montoux negative healthy children was taken as control by detecting IgM and IgG antibodies to A60 antigen. Response to anti-tubercular treatment was observed in all the suspected cases of TBM. This study showed that specificity for diagnosis of TBM by detecting IgM and IgG antibodies in sera was 90% and 80% respectively. Sensitivity of the test by detecting IgM and IgG antibodies in sera was 85% and 80% respectively with positive predictive value of 89.47% for IgM antibody and 80% for IgG antibody. In CSF IgM and IgG antibodies were found in 75% and 60% cases respectively. Both were positive only in 60% of cases. It is concluded from this study that 80-85% cases of TBM in paediatric age group have eigher IgM or IgG antibodies in sera whereas 60-75% have antibodies in CSF.

Bacteriological study of drinking water during epidemic of cholera in Delhi.

Sixty drinking water samples collected from various sources in different areas of Delhi during epidemic of cholera and gastroenteritis were analysed for bacteriological standards. Only 27 (45 per cent) samples were found to be satisfactory for human consumption. Remaining thirty-three (55 per cent) samples showed presence of coliform organisms with MPN value ranging from 10 to 1800+ per 100 ml. Among these positive samples, 31 (93.9 per cent) samples contained faecal coli. Twenty out of thirty (66.6 per cent) Hand pump, 9 out of 21 (42.8 per cent) Taps 2 out of 4 (50 per cent) Tube well and 2 out of 5 (40 per cent) of miscellaneous sources showed contamination with coliform organisms.