Investigation of bundling pilus (BFP) factor in the pathogenesis of Escherichia coli and antibiotic resistance by molecular methods

This study aims to reveal the synergistic effect of the alcoholic extract of rosemary leaves on Escherichia coli bacteria isolated from various pathological conditions. Therefore, 302 clinical samples were collected from various pathological cases from Al-Ramadi and Fallujah Training Hospitals between 20.02-11.05.2021. For the phenotypic diagnosis of bacterial isolates, they were cultured on MacConkey agar, blood agar and eosin methyl blue media. Then, the isolates were identified by traditional methods and microscopic and biochemical examinations were made. As a result of these examinations, it was determined that 107 isolates belonged to E. coli bacteria and this result was confirmed with the Vitek 2 system. In addition, antibiotic susceptibility testing was performed against 12 types of antibiotics in all E. coli isolates. Accordingly, most of the isolates showed resistance and susceptibility to antibiotics and the highest resistance was Tetracycline (82.24%), Ceftazidime (79.44%) and Aztreonam (85.98%), the highest susceptibility was to Imipenem (85.05%), Meropenem (80.37%) and Cefepime (80.03%). While determining the biofilm forming ability of E. coli isolates using the microtitration pots (MTP) method, it was shown that 56 E. coli isolates formed biofilms with two different biofilm formation levels. When biofilm forming bacterial isolates were treated with the alcoholic extract of rosemary leaves, the percentage of biofilm inhibition was higher than the untreated isolates on the rate of biofilm inhibition. In addition, polymerase chain reaction (PCR) technique was used to investigate the FLU gene in E. coli isolates by extraction of DNA. Electrophoresis results showed that all E. coli isolates contained the FLU gene. To examine the response of E. coli bacteria to the synergistic effect of rosemary leaf extract, gene expression of the selected FLU gene was determined by qRT-PCR. An increase in gene expression was seen when treated with rosemary and the antibiotic ciprofloxacin, while a decrease in gene expression was seen for the antibiotic ceftazidime.