Molecular analysis of drug-resistant Mycobacterium tuberculosis isolates collected from patients with pulmonary tuberculosis in central Poland

Abstract number: 1733_1492

Jagielski T., Augustynowicz-Kopec E., Kozinska M., Zabost A., Klatt M., Zwolska Z.

Objective: Although the incidence of tuberculosis (TB) in Poland is steadily decreasing, the prevalence of primary drug-resistant TB, including multidrug resistance (MDR), has been on the rise over the last few years. Therefore, continued surveillance and monitoring of TB epidemiology are required. Currently, molecular typing methods have become a useful tool for tracking and control of transmission of drug-resistant TB. The aim of this study was the molecular characterisation of drug-resistant Mycobacterium tuberculosis clinical isolates.

Materials and Methods: A total of 48 clinical isolates of M. tuberculosis representing 48 non-related, adult patients with resistant pulmonary tuberculosis in central Poland in 2004 were analysed by spoligotyping and newly devised PCR-based method designated IS6110-Mtb1/Mtb2 PCR. Species identification and drug susceptibility testing had been performed beforehand.

Results: Among strains tested, a total of 26 distinct spoligotypes were identified. Unique spoligotype patterns were observed in 19 (39.6%) isolates and the remaining 29 (60.4%) isolates were grouped within 7 clusters, made up of 2–8 isolates. When compared with an international spoligotyping database SpolDB4, 13 (27.1%) of the 19 unique profiles shared already described spoligotypes, whereas the rest 6 (12.5%) did not match any existing spoligotype and were defined as orphans. Of the 7 recognized clusters, one had not been described in SpolDB4. This cluster, comprising 4 isolates, seem to be specific for the study setting. Interestingly, two members of the Beijing family were identified.

Of the 7 spoligotyping clusters, 3 were not confirmed and 2 were partially confirmed by IS6110-Mtb1/Mtb2 PCR. Only two spoligotyping clusters, comprising 2 and 4 isolates, respectively, were identical both with spoligotyping and IS6110-Mtb1/Mtb2 analysis.

Table 1. Comparison of discriminating power among two genotyping methods used in this study

TechniqueNo. of clustered isolates (%)No. of clustersSize of cluster
Spoligotyping29 (60.4)72–8
IS6110-Mtb1/2 PCR12(25)42–4

Conclusions: Molecular analysis by using two genotyping methods, undertaken in 48 drug-resistant M. tuberculosis isolates, showed a variety of different genetic profiles. Spoligotyping overestimated by about 2.5 times the number of clustered isolates, compared to IS6110-Mtb1/Mtb2 PCR. A combination of spoligotyping and IS6110-Mtb1/Mtb2 PCR showed 12 (25%) strains to be clustered, suggesting possible recent transmission.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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