Genetic heterogeneity in Mycobacterium tuberculosis isolates reflected in IS6110 restriction fragment length polymorphism patterns as low-intensity bands - PubMed (original) (raw)

Genetic heterogeneity in Mycobacterium tuberculosis isolates reflected in IS6110 restriction fragment length polymorphism patterns as low-intensity bands

A S de Boer et al. J Clin Microbiol. 2000 Dec.

Abstract

Mycobacterium tuberculosis isolates with identical IS6110 restriction fragment length polymorphism (RFLP) patterns are considered to originate from the same ancestral strain and thus to reflect ongoing transmission. In this study, we investigated 1,277 IS6110 RFLP patterns for the presence of multiple low-intensity bands (LIBs), which may indicate infections with multiple M. tuberculosis strains. We did not find any multiple LIBs, suggesting that multiple infections are rare in the Netherlands. However, we did observe a few LIBs in 94 patterns (7.4%) and examined the nature of this phenomenon. With single-colony cultures it was found that LIBs mostly represent mixed bacterial populations with slightly different RFLP patterns. Mixtures were expressed in RFLP patterns as LIBs when 10 to 30% of the DNA analyzed originated from a bacterial population with another RFLP pattern. Presumably, a part of the LIBs did not represent mixed bacterial populations, as in some clusters all strains exhibited LIBs in their RFLP patterns. The occurrence of LIBs was associated with increased age in patients. This may reflect either a gradual change of the bacterial population in the human body over time or IS6110-mediated genetic adaptation of M. tuberculosis to changes in the environmental conditions during the dormant state or reactivation thereafter.

PubMed Disclaimer

Figures

FIG. 1

FIG. 1

IS_6110_ RFLP patterns of isolates, showing LIBs, and SCCs, from three different patients (A to C). Lanes 1 show the banding patterns of the isolates, with LIBs indicated by arrows. Lanes 2 to 5 show the banding patterns of SCCs of these isolates. The numbers on the right indicate the sizes of standard DNA fragments in kilobase pairs.

FIG. 2

FIG. 2

IS_6110_ RFLP patterns of different mixtures of the DNAs of two M. tuberculosis strains. Lanes 1 and 21 show the RFLP patterns of the pure DNAs of the two strains. Lanes 2 to 20 show the patterns of mixtures of the DNAs of these strains. The numbers in the second horizontal row indicate the ratios of the DNA mixtures. The numbers on the left indicate the sizes of standard DNA fragments in kilobase pairs.

FIG. 3

FIG. 3

IS_6110_ RFLP patterns of different mixtures of the DNAs of two SCCs of an M. tuberculosis strain differing in a single IS_6110_ element. Lane 1 shows the pattern of pure DNA of one SCC. Lanes 2 to 21 depict patterns of mixtures of this DNA with an increasing amount of DNA of another SCC containing an additional IS_6110_ copy at a _Pvu_II restriction fragment of approximately 3.5 kb. The numbers in the second horizontal row indicate the ratios of the DNA mixtures. The numbers on the left indicate the sizes of standard DNA fragments in kilobase pairs.

FIG. 4

FIG. 4

IS_6110_ RFLP patterns of three patient isolates of a cluster showing an LIB (indicated by the arrow) at the same _Pvu_II restriction fragment. The numbers on the right indicate the sizes of standard DNA fragments in kilobase pairs.

FIG. 5

FIG. 5

Frequency distribution of 6,189 normal-intensity bands (NIB) and 69 LIBs per band position category (GelCompar band position and sizes of standard DNA fragments in kilobase pairs).

Comment in

Similar articles

Cited by

References

    1. Barnes P F, el-Hajj H, Preston-Martin S, Cave M D, Jones B E, Otaya M, Pogoda J, Eisenach K D. Transmission of tuberculosis among the urban homeless. JAMA. 1996;275:305–307. - PubMed
    1. Bauer J, Yang Z, Poulsen S, Andersen A B. Results from 5 years of nationwide DNA fingerprinting of Mycobacterium tuberculosis complex isolates in a country with a low incidence of M. tuberculosis infection. J Clin Microbiol. 1998;36:305–308. - PMC - PubMed
    1. Borgdorff M W, Nagelkerke N, van Soolingen D, de Haas P E W, Veen J, van Embden J D A. Analysis of tuberculosis transmission between nationalities in the Netherlands in the period 1993–1995 using DNA fingerprinting. Am J Epidemiol. 1998;147:187–195. - PubMed
    1. Butcher P D, Hutchinson N A, Doran T J, Dale J W. The application of molecular techniques to the diagnosis and epidemiology of mycobacterial diseases. Soc Appl Bacteriol Symp Ser. 1996;25:53S–71S. - PubMed
    1. Cole S T, Brosch R, Parkhill J, Garnier T, Churcher C, Harris D, Gordon S V, Eiglmeier K, Gas S, Barry III C E, Tekaia F, Badcock K, Basham D, Brown D, Chillingworth T, Connor R, Davies R, Devlin K, Feltwell T, Gentles S, Hamlin N, Holroyd S, Hornsby T, Jagels K, Krogh A, McLean J, Moule S, Murphy L, Oliver K, Osborne J, Quail M A, Rajandream M A, Rogers J, Rutter S, Seeger K, Skelton J, Squares R, Squares S, Sulston J E, Taylor K, Whitehead S, Barrell B G. Deciphering the biology of Mycobacterium tuberculosis from the complete genome sequence. Nature. 1998;393:537–544. - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources