Abstract
Background: Traditional contact investigation is an important tool for controlling tuberculosis. It may also help to indicate drug susceptibility patterns when Mycobacterium tuberculosis cultures are not available. Such investigations often underestimate the degree of transmission found by genotyping, but overestimation may also occur. This report is the result of a routine successive DNA restriction fragment length polymorphism (RFLP) analysis of M tuberculosis isolated in Norway.
Method: Fifteen immigrants belonging to the same community were notified with tuberculosis during February to September 2003. The mycobacterial isolates were analysed by RFLP.
Results: All 15 patients had social contact with each other and 13 belonged to the same church community. A total of 14 cultures were positive for M tuberculosis. Among these isolates, six different genotypes were found. Five patients had not acquired the infection from the putative source.
Conclusions: Reactivation of tuberculosis may occur in contacts during the development of an outbreak. In such situations, traditional contact investigations may overestimate the rate of transmission found by genotyping of M tuberculosis. When cultures are unavailable and presumed drug susceptibility patterns are based on that of contacts, such overestimation may lead to incorrect treatment of a patient. Contact investigations must be combined with genotyping of M tuberculosis to conclude how tuberculosis is transmitted. This is especially important in persons with several risk factors for infection.
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Selected References
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- Behr M. A., Hopewell P. C., Paz E. A., Kawamura L. M., Schecter G. F., Small P. M. Predictive value of contact investigation for identifying recent transmission of Mycobacterium tuberculosis. Am J Respir Crit Care Med. 1998 Aug;158(2):465–469. doi: 10.1164/ajrccm.158.2.9801062. [DOI] [PubMed] [Google Scholar]
- Dahle Ulf R., Sandven Per, Heldal Einar, Caugant Dominique A. Continued low rates of transmission of Mycobacterium tuberculosis in Norway. J Clin Microbiol. 2003 Jul;41(7):2968–2973. doi: 10.1128/JCM.41.7.2968-2973.2003. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Daley Charles L. Tuberculosis contact investigations: please don't fail me now. Am J Respir Crit Care Med. 2004 Apr 1;169(7):779–781. doi: 10.1164/rccm.2401012. [DOI] [PubMed] [Google Scholar]
- Heldal E., Dahle U. R., Sandven P., Caugant D. A., Brattaas N., Waaler H. T., Enarson D. A., Tverdal A., Kongerud J. Risk factors for recent transmission of Mycobacterium tuberculosis. Eur Respir J. 2003 Oct;22(4):637–642. doi: 10.1183/09031936.03.00019103. [DOI] [PubMed] [Google Scholar]
- Ruddy M. C., Davies A. P., Yates M. D., Yates S., Balasegaram S., Drabu Y., Patel B., Lozewicz S., Sen S., Bahl M. Outbreak of isoniazid resistant tuberculosis in north London. Thorax. 2004 Apr;59(4):279–285. doi: 10.1136/thx.2003.010405. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Small P. M., Hopewell P. C., Singh S. P., Paz A., Parsonnet J., Ruston D. C., Schecter G. F., Daley C. L., Schoolnik G. K. The epidemiology of tuberculosis in San Francisco. A population-based study using conventional and molecular methods. N Engl J Med. 1994 Jun 16;330(24):1703–1709. doi: 10.1056/NEJM199406163302402. [DOI] [PubMed] [Google Scholar]
- van Deutekom Henk, Hoijng Susan P., de Haas Petra E. W., Langendam Miranda W., Horsman Alice, van Soolingen Dick, Coutinho Roel A. Clustered tuberculosis cases: do they represent recent transmission and can they be detected earlier? Am J Respir Crit Care Med. 2003 Dec 18;169(7):806–810. doi: 10.1164/rccm.200306-856OC. [DOI] [PubMed] [Google Scholar]