Typing of Indian S.Typhi Isolates with Special Reference to Pulsotypes

Six hundred sixty-four isolates from 23 different centres of North, central and South zones of India were typed by Pulsed Field Gel Electrophoresis (PFGE). Eighty-nine different profile were delineated which were divided into 16 groups. X-15 was the commonest PFGE profile. The typeability of PFGE and phage typing was 100% and 76.4% whereas the discriminatory power was 0.91 and 0.25 respectively. The dice coefficient varied between 0.64-1. E1 was the predominant phage type. No significant association was found between pulsotypes and phage types of the S.Typhi isolates. X38 pulsotype was associated with ciprofloxacin resistant S. Typhi and X69 pulsotype was associated with cefotaxime resistant S.Typhi isolates.