1Junior Resident, Dept. of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, Uttrakhand
2Associate Professor, Dept. of Microbiology, Himalayan Institute of Medical Sciences, Dehradun, Uttrakhand
3Professor, Dept. of Medicine, Yenepoya Medical College, Mangalore, Karnataka
4Professor, Dept. of Pulmonary Medicine, All India Institute of Medical Sciences, Rishikesh, Uttarakhand
*Corresponding Author: Email: doctorbiswaroopchatterjee@gmail.com
Online published on 3 April, 2018.
Rapid Slide Culture (RSC) was compared with the standard diagnostic strategy of simultaneous culture in Löwenstein-Jensen medium (L-J) and Mycobacterial Growth Indicator Tubes (MGIT™) with regard to diagnostic accuracy, turnaround time and cost, for isolating M. tuberculosis (MTB) from bronchoalveolar lavage (BAL) specimens.
Centrifuged deposits of 75 consecutive smear-positive and 75 randomly selected smear-negative BAL specimens were subjected to RSC as well as culture in both L-J and MGIT. Isolates were identified as MTB by standard methods.
One hundred and ten (73.3%) specimens were culture-positive by L-J and/or MGIT; 99 (90%) of these were RSCpositive too. No RSC-positive specimen was culture-negative on both L-J and MGIT. Thus, RSC demonstrated an overall sensitivity, specificity, PPV and NPV of 90%, 100%, 100% and 78% respectively. Significantly, 25 (33%) smear-negative specimens were RSC-positive, indicating the ability of RSC to isolate MTB from specimens with low bacillary loads. The mean time to positivity was seven, 35 and 24 days for RSC, L-J, and MGIT respectively. The cost per test was the equivalent of USD 1.82, 1.34, and 10.42 for RSC, L-J and MGIT respectively.
Rapid Slide Culture proved to be a rapid, effective and low-cost method for culturing MTB from bronchoalveolar lavage fluid, when compared with conventional culture in L-J medium and MGIT.
Tuberculosis, Bronchoalveolar lavage, Diagnosis, Culture
