Email updates

Keep up to date with the latest news and content from BMC Research Notes and BioMed Central.

Open Access Research article

Comparison of Mycobacterium tuberculosis drug susceptibility using solid and liquid culture in Nigeria

Lovett Lawson1*, Nanmdi Emenyonu1, Saddiq T Abdurrahman2, Juliana O Lawson1, Gertrude N Uzoewulu3, Olumide M Sogaolu4, Juliana N Ebisike5, Christopher M Parry6, Mohammed A Yassin7 and Luis E Cuevas7

Author Affiliations

1 Zankli Medical Centre, Plot 1021 Shehu YarAdua Way, Abuja, Nigeria

2 National Tuberculosis and Leprosy Control Programme, Abuja, Nigeria

3 Nnamdi Azikiwe Teaching Hospital, Nnewi, Nigeria

4 University College Hospital (UCH), Ibadan, Nigeria

5 Wuse General Hospital, Abuja, Nigeria

6 Mahidol-Oxford Tropical Medicine Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia

7 School of Tropical Medicine, Liverpool, UK

For all author emails, please log on.

BMC Research Notes 2013, 6:215  doi:10.1186/1756-0500-6-215

Published: 30 May 2013

Abstract

Background

This study compares Mycobacterium tuberculosis culture isolation and drug sensitivity testing (DST) using solid (LJ) and liquid (BACTEC-MGIT-960) media in Nigeria.

Methods

This was a cross sectional survey of adults attending reference centres in Abuja, Ibadan and Nnewi with a new diagnosis of pulmonary tuberculosis (TB) or having failed the first-line TB treatment. Patients were requested to provide three sputum specimens for smear-microscopy and culture on LJ and BACTEC-MGIT-960. Positive cultures underwent DST for streptomycin, isoniazid, rifampicin and ethambutol.

Results

527 specimens were cultured. 428 (81%) were positive with BACTEC-MGIT-960, 59 (11%) negative, 36 (7%) contaminated and 4 (1%) had non-tuberculosis mycobacteria (NTM). 411 (78%) LJ cultures were positive, 89 (17%) negative, 22 (4%) contaminated and 5 (1%) had NTM. The mean (SD) detection time was 11 (6) and 30 (11) days for BACTEC-MGIT-960 and LJ. DST patterns were compared in the 389 concordant positive BACTEC-MGIT-960 and LJ cultures. Rifampicin and isoniazid DST patterns were similar. Streptomycin resistance was detected more frequently with LJ than BACTEC-MGIT-960 and ethambutol resistance was detected more frequently with BACTEC-MGIT-960 than LJ, but differences were not statistically significant. MDR-TB was detected in 27 cases by LJ and 25 by BACTEC-MGIT-960 and using both methods detected 29 cases.

Conclusions

There was a substantial degree of agreement between the two methods. However using the two in tandem increased the number of culture-positive patients and those with MDR-TB. The choice of culture method should depend on local availability, cost and test performance characteristics.

Keywords:
Multi-drug resistant tuberculosis; First-line anti-TB drugs; Solid culture; Liquid culture; Drug sensitivity