The IS6110 Restriction Fragment Length Polymorphism in Particular Multidrug-Resistant Mycobacterium tuberculosis Strains May Evolve Too Fast for Reliable Use in Outbreak Investigation

Pathobiology Institute CICV/INTA, Morón, Argentina.
Journal of Clinical Microbiology (Impact Factor: 3.99). 04/1999; 37(3):788-91.
Source: PubMed


To study possible nosocomial transmission of multidrug-resistant (MDR) Mycobacterium tuberculosis, strain types and other information on 24, mostly human immunodeficiency virus-positive patients, were collected. Isolates from 11 patients had identical IS6110 restriction fragment length polymorphism (RFLP) patterns as well as spoligotype patterns and resistance profiles. Noticeably, nine other isolates from related cases also exhibited identical spoligotypes but slightly different RFLP patterns. These results indicate that for some MDR strains, the evolutionary clock of IS6110 RFLP may run too fast for reliable interpretation of strain typing results over a period of a few years.

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Available from: María Isabel Romano, Mar 10, 2014
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    • "One RFLP method is IS6110 RFLP, which analyzes the polymorphism of the insertion sequence 6110 (IS6110), which is the typical repetitive sequence of the Mycobacterium tuberculosis complex. IS6110 RFLP has shown high discriminatory power and sensitivity and it has been widely used for molecular typing of the M. tuberculosis complex [2,14,23]. However, the IS6110 RFLP method is not applicable to the typing of M. bovis because M. bovis has only a single or a few IS6110 copies [6]. "
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    ABSTRACT: Bovine tuberculosis (TB) is a major zoonosis that's caused by Mycobacterium bovis (M. bovis). Being able to detect M. bovis is important to control bovine TB. We applied a molecular technique, the variable number tandem repeat (VNTR) typing method, to identify and distinguish the M. bovis isolates from Gyeonggi-do, Korea. From 2003 to 2004, 59 M. bovis clinical strains were isolated from dairy cattle in Gyeonggi-do, Korea, and these cattle had tuberculosis- like lesions. Twenty-four published MIRUVNTR markers were applied to the M. bovis isolates and ten of them showed allelic diversity. The most discriminatory locus for the M. bovis isolates in Korea was QUB 3336 (h = 0.64). QUB 26 and MIRU 31 also showed high discriminative power (h = 0.35). The allelic diversity by the combination of all VNTR loci was 0.86. Six loci (MIRU 31, ETR-A and QUB-18, -26, -3232, -3336) displayed valuable allelic diversity. Twelve genotypes were identified from the 59 M. bovis isolates that originated from 20 cattle farms that were dispersed throughout the region of Gyenggi-do. Two genotypes [designation index (d.i.) = e, g] showed the highest prevalence (20% of the total farms). For the multiple outbreaks on three farms, two successive outbreaks were caused by the same genotype at two farms. Interestingly, the third outbreak at one farm was caused by both a new genotype and a previous genotype. In conclusion, this study suggests that MIRU-VNTR typing is useful to identify and distinguish the M. bovis isolates from Gyeonggi-do, Korea.
    Preview · Article · Jul 2008 · Journal of Veterinary Science
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    • " in RFLP patterns . This means that two isolates that differ by only one copy should not be considered as different , especially if the copy number is greater than five , as pattern variations with time have been described by several authors , especially in patients infected for a long time with the same multiresistant strain of M . tuberculosis ( Alito et al . , 1999 ; Niemann et al . , 1999 ) , or within clusters of patients possibly infected by the same strain ( Ijaz et al . , 2002 ) . The DR marker is clearly more stable than the IS6110 ( Aranaz et al . , 1998 ; Filliol et al . , 2000a ; Yeh et al . , 1998 ) . This has been confirmed by studies in both M . bovis ( Durr et al . , 2000a ) and in M "
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    ABSTRACT: Until recently, none of the Mycobacterium bovis typing techniques permitted a satisfactory differentiation of isolates. During the last 10 years, the genome of pathogenic mycobacteria has been extensively studied, and phylogenetic analyses have shown that all (except Mycobacterium avium) belong to a single genetic species: the Mycobacterium tuberculosis complex. This increase in knowledge about the genome of these bacteria has lead to the discovery of molecular markers that allow us to differentiate isolates. Because of the phylogenetic proximity of the strains, even if most of these markers have been discovered in M. tuberculosis, they could be successfully adapted to the other bacteria of the M. tuberculosis complex, especially M. bovis. The most common markers in use today are the IS6110 insertion sequence, the direct repeat (DR) region, the poly(GC) rich (PGRS) sequences and the variable number tandem repeats (VNTR) sequences. The corresponding typing techniques are briefly described, and current knowledge of polymorphism and marker stability is detailed. If molecular markers are to offer wide perspectives for field studies, these two characteristics (polymorphism and stability) must be taken into account when choosing the marker(s) used in a study. In this context, examples of the application of molecular typing techniques for M. bovis are reviewed, on the one hand with epidemiological studies for which the major problem is the comparison between isolates and, on the other, with more general studies about the population genetics of M. bovis in a given country, and about its history and its phylogeny.
    Full-text · Article · Mar 2004 · Research in Veterinary Science
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    ABSTRACT: During a population-based study to genotype isolates of Mycobacterium tuberculosis from Buenos Aires Northern suburbs, we found isolates with molecular patterns related to those of the Beijing genotype. Five out of 590 (0.85%) patients had isolates with spoligopattern identical to that of the Beijing family. Since two of these isolates showed identical IS6110RFLP pattern, we found only four different patterns containing 11 to 19 bands. The isolates were obtained from young people (including a 7 years-old child) who were born in Argentina, and were living in a small area of our region. However, conventional contact tracing did not prove epidemiological linkage among them. These isolates were fully drug-susceptible to the first-line drugs. The comparison of the IS6110RFLP patterns from our isolates against a set of 19 reference Beijing patterns from the RIVM (The Netherlands) confirmed that the strains belonged to the Beijing lineage. These findings might be partially explained by the important migration phenomena occurred during the last decade. Further surveillance studies would help in the following of Beijing family strain dissemination in our community.
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