Epidemiological study of tuberculosis in the area of Angers,France, as studied by 3 PCR-based fingerprinting methods

The new genotyping methods efficiently complement classical epidemiological investigation in order to attempt a global approach to TB control. In the present work, we have studied the genomic diversity of Mycobacterium tuberculosis isolated during the year 1998 within the district of Angers, France (260,000 inhabitants distributed in 29 districts), in order to identify recent transmission events and any related risk factors. The methods used included "spacer oligonucleotide typing" or spoligotyping, "variable number of DNA tandem repeats" or VNTR, and "double repetitive element PCR" or DRE-PCR. The resulting spoligotyping and VNTR results were also feeded to international databases and compared with >10,000 isolates for spoligotyping and 500 isolates for VNTR, representative of about 60 countries. The results obtained underlined that most of the TB cases in our setting probably reflected reactivation cases, as clustered cases indicative of potential events of recent transmission were rare. Furthermore, interrogation of international databases showed that most of the isolates from the Angers region belonged to major conserved families of TB isolates representative of Europe, with only rare cases of Asian origin, or those previously reported in specific epidemies reported from elsewhere.