Escherichia coli O157:H7; PO157 epidemiology etiology isolation and identification

The E. coli bacterium, specifically the serotype E. coli O157:H7, has garnered attention due to its association with foodborne illnesses and outbreaks. This particular serotype is renowned for its ability to cause various gastrointestinal symptoms in humans, ranging from mild diarrhea to severe conditions such as hemorrhagic colitis and hemolytic uremic syndrome (HUS). Particularly vulnerable populations to severe E. coli O157:H7 infections include children, the elderly, and individuals with weakened immune systems. The aim of this thesis study was to determine the prevalence of E. coli O157:H7 in children in the city of Salahuddin, Iraq, investigate the course of E. coli infections, explore the resistance profiles of the pathogen, and examine the general characteristics of patients with E. coli infections. The study was conducted at 14 departments of Balad General Hospital in Salahuddin, Iraq. For this purpose, samples were collected from 122 patients from March 2022 to August 2022. In terms of gender distribution, 59 (48.36%) were male, and 63 (51.64%) were female. It was determined that 85 cases (69.67%) were spontaneous, while 37 cases (30.33%) were admitted to the hospital for other reasons. According to the patient follow-up investigation, it was found that 114 patients (93.8%) recovered from the disease, while 8 (6.56%) unfortunately succumbed to it. The microbiological analysis and biochemical tests conducted in the study revealed that E. coli O157:H7 was isolated in 60 out of 75 HUS stool samples (80%) and 35 out of 47 ADD stool samples (74.46%). After applying the latex agglutination test with O antiserum, 7 of these samples tested positive for O157 antigen. Cultural methods indicated significant growth of E. coli in 102 out of 122 stool samples. Analysis conducted through the PCR method showed that 77 out of 122 samples (75.49%) were confirmed to be E. coli O157:H7.