Molecular epidemiology of <e1>Shigella flexneri</e1> in a diarrhoea-endemic area of Lima, Peru<fnr rid="fn1"><fn id="fn1">The views expressed herein are those of the authors and do not necessarily represent those of the Department of the Army or the Department of Defense (para 4-3, AR 360-5).</fn>

A year-long community-based study of diarrhoeal diseases was conducted in Canto Grande, a periurban community in Lima, Peru. In 109 (34%) houses out of 323 that were visited, at least one individual was detected with shigellosis. The frequency of the 161 shigella isolates obtained was as follows: 117 <e1>S. flexneri</e1> (73%), 21 <e1>S. boydii</e1> (13%), 15 <e1>S. dysenteriae</e1> (9%), and 8 <e1>S. sonnei</e1> (5%). Using a non-radioactive <e1>ipaH</e1> gene probe as a molecular epidemiological tool, a total of 41 <e1>S. flexneri</e1> strains were shown to be distributed in 25 intra-family comparisons by pairs (icp). Further subdivision, based on a comparison of the serotype, plasmid profile, antibiotic resistances and <e1>ipaH</e1> hybridization patterns indicated that Group I, with 11 icp (44%), had strains that were identical, Group II with 8 icp (32%), had strains that were different and Group III with 6 icp (24%), had strains with the same serotype and identical <e1>ipaH</e1> profiles but with differences in other markers. This data indicates that a diversity of shigella clones circulated in this community resulting from both clonal spread and horizontal transfer of genetic elements. Furthermore, <e1>ipaH</e1> profiling of isolates can be used not only to differentiate between closely related shigella strains but also with other parameters, help to understand the dynamics of the generation of new clones of pathogenic bacteria.