Molecular characteristics of Shigella spp. isolated from patients with diarrhoea in a new industrialized area of Thailand

<jats:p>In this study, we used plasmid profile analysis, <jats:italic>Xba</jats:italic>I macrorestriction with pulsed-field gel electrophoresis (PFGE), and PCR of the <jats:italic>ipaH</jats:italic> gene, to study the molecular characteristics of 183 <jats:italic>Shigella</jats:italic> spp. isolated during May 2000 to April 2003 from rectal swabs of patients with watery and/or bloody diarrhoea in a new industrialized area of Thailand. Among the 183 isolates, 167 were <jats:italic>S. sonnei</jats:italic> and 16 were <jats:italic>S. flexneri</jats:italic>. For plasmid profile analysis, the 183 isolates revealed 16 different plasmid patterns, designated patterns A to P. The sizes of the plasmid bands were: 6, 5·5, 5, 4·5, 4, 3·25, 2·75, 2·5, 2, 1·75, 1·5 and/or 1·25 kb. The frequency of each plasmid band was 4·5 kb (165 isolates), 3·25 kb (161 isolates), 5·5 kb (129 isolates), 1·75 kb (121 isolates), 1·5 kb (35 isolates), 5 kb (21 isolates), 2 kb (16 isolates), 2·75 kb (12 isolates), 1·25 kb (9 isolates), and 6 kb (8 isolates). PFGE analysis revealed 45 different <jats:italic>Xba</jats:italic>I macrorestricted DNA banding patterns which could be grouped into 11 groups. All the isolates gave PCR amplicons of the <jats:italic>ipaH</jats:italic> gene. Plasmid profile analysis and PFGE are powerful tools for differentiation of the <jats:italic>Shigella</jats:italic> spp. This study provides important data on the molecular characteristics of <jats:italic>Shigella</jats:italic> isolates in Thailand, which could be useful as an epidemiological baseline for identifying relationships with strains that may emerge in the future.</jats:p>