Molecular fingerprinting of Mycobacterium tuberculosis on a Caribbean island with IS6110 and DRr probes

Abstract

Because of a substantial increase in human immunodeficiency virus (HIV) infection and HIV-linked tuberculosis in the Caribbean, a molecular fingerprinting study of clinical isolates of Mycobacterium tuberculosis isolated at the Pasteur Institute of Guadeloupe from 1994 to 1995 was undertaken with the insertion sequence IS6110 and the direct repeat DRr probes. We present the results for 72 isolates from 51 patients. A major cluster (cluster A) representing isolates from 12 patients (24%) was detected upon PvuII-IS6110 fingerprinting, which revealed a pattern of four bands among these isolates. Homogeneity was retained when the isolates were further analyzed with the DRr probe or further characterized by AluI and SmaI-DRr restriction fragment length polymorphism analysis. The isolates of cluster A, from 10 men and 2 women, was present in people of all ages and of different ethnic and geographical backgrounds, and infection with these isolates was independent of the HIV status of the patients (except for 2 HIV-positive patients from the same ward from whom the tubercle bacilli were isolated at the same time). The percentage of reactivation versus active transmission events could not be precisely determined in this study. These results are discussed on the basis of the genetic advantage of predominant clusters and/or specific characteristics of the settings from which a similar cluster of isolates with four bands has so far been reported, which include South Africa, French Polynesia, and Guadeloupe.

Follow up of Mycobacterium tuberculosis transmission in the French West Indies by IS6110-DNA fingerprinting and DR-based spoligotyping

“…DNA was prepared by cetyl-trimethyl-ammonium bromide method [13] and PvuII-IS6110-RFLP was performed using the standard protocol [9,14] with Mt14323 as an external marker every four lanes in electrophoresis experiments. All the isolates were typed twice, whereas clustered isolates were run on gels one additional time, and the RFLP patterns were found to be reproducible in each case.…”

“…All the isolates were typed twice, whereas clustered isolates were run on gels one additional time, and the RFLP patterns were found to be reproducible in each case. Furthermore, all clustering results were also con¢rmed by DR-RFLP which was performed as previously described [7,9]. The analysis of similarity was performed with the Taxotron software package (P.A.D.…”

“…The analysis of similarity was performed with the Taxotron software package (P.A.D. Grimont and Taxolab, Institut Pasteur, Paris, France) as reported previously [9].…”

“…The IS6110 patterns were scanned and computed as reported previously [9] with the Taxotron 0 software package (P.A.D. Grimont and Taxolab, Institut Pasteur, Paris, France) which comprises the Re-strictoScan, RestrictoTyper, Adanson, Recognizer, and Dendrograf programs.…”

“…Nevertheless, the diversity of IS6110 patterns around the world is theoretically limited by the number of IS copies found in certain regions such as East Asia [5] and the cloning of an insertion preferential locus (ipl) argues against this diversity and thereby against the use of this sole typing system in global epidemiological studies [6]. The use of the 36-mer oligonucleotide of the DR locus (DR-RFLP) [7] sometimes made it possible to subtype IS6110-de¢ned clusters and thereby to more accurately identify possible epidemiological links [8,9]. Recently a new method, designated`spoligotyping', has been described [10] which utilizes the sequence diversity of inter-DR spacers, and allows simultaneous detection and typing without having to obtain cultures.…”