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Typing of Legionella pneumophila and its Role in Elucidating the Epidemiology of Legionnaires’ Disease, Page 1 of 2
< Previous page Next page > /docserver/preview/fulltext/10.1128/9781555815660/9781555813901_Chap25-1.gif /docserver/preview/fulltext/10.1128/9781555815660/9781555813901_Chap25-2.gifAbstract:
The main reason for typing Legionella pneumophila is to help identify environmental sources giving rise to cases of legionellosis, thus allowing control measures to be implemented and further cases to be prevented in a timely manner. Monoclonal antibody (mAB) subgrouping is probably the most rapid and reliable phenotypic method available and is excellent for initial screening of isolates. Only a few of the many genotypic methods described have been shown to meet these exacting requirements. Of these, pulsed-field gel electrophoresis is the most widely applied, but others have also been used. For example, a restriction-fragment length polymorphism (RFLP) typing method was used as the standard method in the United Kingdom for almost 20 years. Investigation of travel-associated legionellosis requires even more rigorously standardized systems, as not only must the types be clearly defined but they also must be recognizable and reproducible in laboratories in different countries (different laboratories, different times). The standardized sequence-based typing (SBT) method targets part of six genes (flaA, pilE, asd, mip, mompS, proA), each of which shows considerable allelic variation, thus providing an extremely discriminatory typing system. Furthermore, of the seven major-outbreak-associated strains for which SBT data are available, five are SBT 3,4,1,1,14,9. However, if substantiated, these observations have important and widespread implications for our understanding of the epidemiology of legionellosis and for the monitoring and control of L. pneumophila in the built environment.