Effect of relative centrifugal forces and centrifugation times on recovery of Mycobacterium tuberculosis.
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Date
2014-01
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Abstract
Background: Tuberculosis (TB) is one of the major cause of morbidity and
mortality worldwide, affecting one third of world’s population and the
incidence is much higher in South-East Asia (India and China together account
for nearly 40% of the global TB cases)
Objectives: The current study was designed to evaluate the efficacy of relative
centrifugal forces (RCFs) and various centrifugations times (CTs) on recovery of
Mycobacterium tuberculosis (MTB) from sputum specimens pre-inoculated with
MTB.
Materials & Methods: For this study, direct acid fast bacilli (AFB) smear
negative sputum specimens were randomly collected, which were further
subjected to sterilization ( by autoclaving at 1210 C for 15 min ) and then
seeded with MTB. Afterwards, these sputum specimens were subjected to
centrifugation (in a cold centrifuge) at various RCFs and CTs. After
centrifugation, supernatants and sediments were inoculated on LJ media and
incubated at 370 C with daily monitoring for 8 weeks.
Results: In the current study, as the RCFs (6000xg) and CTs ( 25 min and 20
min) were increased, the growth detection time exponentially decreased (9 and
11 days) and culture grades (4+) were increased when cultured from the
sediments. However, the recovery rates of MTB from the supernatant fluids
were constantly decreased as RCFs and CTs increased.
Conclusion: The current study concluded that a higher RCF of 6000xg and CTs of
20 and 25 min could effectively detect the tubercle bacilli from the sputum
specimens more efficiently than other lower RCFs and CTs.
Description
Keywords
Pulmonary tuberculosis, Mycobacterium tuberculosis, acid fast bacilli, relative centrifugal force, centrifugation time
Citation
Sharma A, Madaan I, Shinu P, Singh VA, Garg A. Effect of relative centrifugal forces and centrifugation times on recovery of Mycobacterium tuberculosis. International Journal of Medical and Dental Sciences. 2014 Jan; 3(1): 257-263.