Escherichia coli sequence type O25b-ST131 has emerged in recent years around the world in combination with CTX-M-15 among extra-intestinal infections and it has caused considerable morbidity and mortality. Management of infections can be done by controlling the source of infections or contamination. In India there are not many studies on O25b-ST131 clone, This study was done to investigate ST131’s prevalence in different phylogenetic groups among isolates from different extra-intestinal infections. Hundred E. coli isolates were isolated from different clinical samples including urine, blood, sputum and exudates from Krishna Rajendra (K.R) Hospital, Mysore. Polymerase chain reaction (PCR) method was used to determine the Phylogenetic groups and O25b-ST131 clone. Out of 100 E. coli strains 55%, 30%, 8% and 7% were isolated from urine, exudates, sputum, and blood respectively. Phylogenetically, B2 group was the dominant group (34%) followed by D, B1 and A groups (28, 26, and12) respectively, 87% E. coli samples belonged to O25b-ST131 clone which were distributed among groups; B2, D, B1 and (32, 25, 22 and 8 isolates respectively). Diversity of Phylogenetic groups among O25b-ST131 E. coli strains may refer to the source of infections. Further studies are needed to highlight the source of infection which
may help to control the dissemination of E. coli clone.
Keywords: E. coli, ExPEC, O25b-ST131 clone, PCR, Phylogenetic groups