Comparison of Ziehl Neelsen and Auramine O staining methods on direct and concentrated smears in clinical specimens.

Background: In developing countries like ours with a large number of tuberculosis (TB) cases and limited resources, the diagnosis of TB relies primarily on smear microscopy for Acid Fast Bacilli (AFB) but its sensitivity is limited in paucibacillary cases. Aim: To evaluate the increase in efficacy of smear microscopy when smears are prepared from clinical samples after concentration by Petroff’s method and stained by Auramine O (AO) fluorescent dye as against Ziehl Neelsen (ZN) staining of similar taking culture as the gold standard. Methods: Smears were prepared from 393 clinical samples both by direct and after Petroff’s concentration and examined by fluorescent microscopy and Ziehl Neelsen method .The concentrated material was also cultured on Lowenstein Jensen media and the results of the two microscopy methods were compared with the culture results taken as the gold standard. Results: Mycobacterial growth was detected in 137(35.77%) specimens, out of which three were non-tubercular mycobacteria. Using culture as the reference method, the sensitivity of direct staining was 55.55% for ZN and 71.85% for AO. Direct fluorescent microscopy detected 9.29% paucibacillary sputum samples that were missed on ZN staining. On concentration, the sensitivity increased by 6.67% for ZN and 11.11% for AO. The sensitivity of AFB smear microscopy increased by 27.41% and was statistically significant (p=<.001) when both methods were combined. The specificity was 99.19% for both ZN and AO. Conclusion: Fluorescent microscopy has higher sensitivity and comparable specificity which is further enhanced by concentration. Now with the advent of newer inexpensive Light Emitting Diode (LED) based fluorescent microscopes (FM), which are easier to use, fluorescent microscopy can be widely used even in peripheral laboratories where culture facilities are not available.

Comparison of MGIT 960 & pyrazinamidase activity assay for pyrazinamide susceptibility testing of Mycobacterium tuberculosis.

Background & objectives: Pyrazinamide is an important front line antimycobacterial drug, which is also being used in the treatment of multi drug resistant tuberculosis along with second line drugs in DOTS plus programme. Conventional testing of pyrazinamide on solid medium is difficult as it is active at acidic pH. Therefore, there is a need for a rapid and simple method for susceptibility testing of pyrazinamide. This study was carried out to compare pyrazinamide susceptibility testing by MGIT 960 and two rapid pyrazinamidase activity tests. Methods: Pyrazinamide susceptibility was tested in 136 clinical isolates of Mycobacterium tuberculosis by MGIT 960 and pyrazinamidase activity was tested by classical Wayne’s method and modified PZase agar method. Results: There was 88.9 per cent concordance between MGIT 960 and classical Wayne’s method and 93.38 per cent with modified method for pyrazinamidase activity. Using MGIT 960 results as gold standard the sensitivity and specificity of Wayne’s method was 88.15 and 90 per cent respectively and that of modified method was 89.4 and 98.3 per cent. Interpretation & conclusions: Our study demonstrates that the modified pyrazinamidase activity test can be used as a screening test to detect resistance to pyrazinamide specially in resource limited settings but confirmation of susceptibility should be done by standard methods like MGIT 960.

Prevalence of reproductive tract infections amongst ever married women and sociocultural factors associated with it.

A community-based study was carried out to assess the prevalence of reproductive tract infections (RTIs) among ever married rural women aged 15 -45 years at village Naila during 2002. Six hundred houses were surveyed and all the eligible women residing in these houses were interviewed by MPWs and Interns and were offered medical examinations at rural health training centre, Naila. At least one symptom related to RTIs was found in 471(55%) out of 859 women. Only 50% (432/859) women gave consent for their gynaecological and microbiological examinations. Out of 432 women examined 61% (263/432) had at least one type of RTIs. Out of 263 cases, 43% had cervicitis, 26% had bacterial vaginitis, 14% had fungal infection, 8% had trichomonas vaginitis, 22% had pelvic inflammatory disease and 19% had cervical erosion. Prevalence of RTI was significantly associated with age, personal hygiene, material used for menstrual blood, gravida status, type of attendance at child birth, invasive contraceptives, gynaecological surgery but caste, literacy status and place of deliveries were not significantly associated with RTI status in the present study.