Molecular Fingerprinting of Mycobacterium tuberculosis and Risk Factors for Tuberculosis Transmission in Paris, France, and Surrounding Area

Abstract

Forty-three percent of the tuberculosis cases reported in France are from the Ile de France region. The incidence of tuberculosis in this region is 33 cases per 100,000 inhabitants, twice the national average. A restriction fragment length polymorphism (RFLP) analysis was performed with clinical isolates of Mycobacterium tuberculosis isolated during 1995 in 10 hospitals in Paris and surrounding areas to detect tuberculosis transmission and define the factors associated with clustering in this population. The molecular markers used were the insertion sequence IS6110 and the direct repeat (DR) sequence. Social, demographic, and clinical data were collected from the patients’ medical files. Ten patients with isolates with a single copy of IS6110 were excluded from further analysis. Twenty-four patients with false-positive cultures due to laboratory contamination (based on RFLP analysis with IS6110 and examination of patient data) were also excluded. The study was then conducted with 272 strains isolated from 272 patients. Further fingerprinting was performed by using the DR element with strains with patterns by RFLP analysis with IS6110that differed by one band only and strains with identical patterns by RFLP analysis with IS6110 and with low numbers of copies of IS6110. The combined use of both markers identified unique patterns for 177 strains and clustered 95 (35.7%) strains in 26 groups, each containing isolates from 2 to 12 patients. The clustering was strongly associated with homelessness and the male sex. It was not associated with age, birth in a foreign country, human immunodeficiency virus positivity, or residence in hostels or prison. Isolates from homeless people were often included in large clusters, and homeless people could be the source of tuberculosis transmission for more than 50% of the clustered patients. These results suggest that homeless people play a key role in the spread of M. tuberculosis in the community and that poor socioeconomic conditions are the main risk factors associated with active tuberculosis transmission.

Molecular epidemiology of tuberculosis and other mycobacterial infections: main methodologies and achievements

“…The LMPCR, a ligation‐mediated method in which a flanking sequence located at the 5′ side of IS 6110 is amplified [145, 146], was compared with spoligotyping and IS 6110 RFLP, and proved to be more discriminatory than spoligotyping and less discriminatory than IS 6110 RFLP [160].…”

“…In recent years, many PCR‐based typing methods have been developed [45, 125, 138–151]. These methods have the advantage that, in principle, few bacteria are sufficient as targets for typing.…”

“…If M. tuberculosis complex isolates have different spoligo patterns, they also reveal, without exception, different IS 6110 RFLPs [108, 154]. The ligation‐mediated PCR [145, 146] has been described to be more effective than spoligotyping for screening on large scale [160].…”

Molecular epidemiology of tuberculosis in Turkey

“…The distribution of these low‐copy‐number isolates was similar in seven geographic regions, and not significantly affected by demographic characteristics. The reported proportion of low‐copy‐number isolates varies from 6% to 16% in European countries [1,6,7], and from 26% to 49% in Asia [6,8,9]. The rate found in Turkey (25%) possibly reflects the fact that this country lies between Europe and Asia.…”

Tuberculosis cluster in an immigrant community: case identification issues and a transcultural perspective

“…Identifying an identical genotype of Mycobacterium tuberculosis in 11 of our 15 patients provided a strong evidence of active transmission in a specific immigrant community in Geneva. Genotyping is a rapid and reliable method, with the IS6110‐RFLP considered the gold standard method to characterize TB transmission (Gutierrez et al. 1998; Luciani et al.…”