التوصيف الجزيئي لبعض عوامل الضراوة في بكتريا Escherichia coli المعزولة من اصابات المسالك البولية في محافظة كربلاء المقدسة

Molecular characterization of some virulence factors in Escherichia coli Isolated from Urinary Tract infections in Sacred Karbala province

Twenty-four E. coli isolates were obtained, and by studying the phenotypic characteristics and biochemical assays, the bacteria appeared on Macunkey medium fermented with lactose sugar, and the color of the colonies was pink, indicating that they were Gram-negative bacteria by lactose fermentation, while the non-fermented colonies appeared The lactose is clear and colorless, as (vitek2) assay showed that all samples under study belong to E. coli bacteria.
As for the results of biochemical tests, it was found that the bacteria contain the capsule, as the capsules are determinants of important virulence elements, which enable pathogenic bacteria to evade or confront the non-specific host defense during the early (pre-immune) stage of infection, As for the results of the tests on the blood agar medium, the colonies were analyzed with a percentage of (79.1%) for blood (type of alpha hemolysis).
The results of biofilm formation through the tube method showed variation in terms of biofilm formation. The number of isolates that formed a strong biofilm was 8 (33.3%), which formed an average biofilm of 10 (41.7%), and finally the number of isolates that formed a weak biofilm 6 (25%).
The sensitivity and resistance of E. coli isolates to ten different antibiotics were selected based on their use in treating infections, including urinary tract infection. The bacteria were varied in their resistance and sensitivity to these tested antibiotics, as all isolates were multi-drug resistance (MDR). The results of the rate of isolates resistance to antibiotics were variable among the antibiotics. The highest percentage of resistance was against penicillin (100%) and metronidazole 100 (%), followed by trimethoprin sulphamethoxazole (87.5%) and nalidixic acid (875%). ) Then Norfloxacin (75%) and Ciprofloxacin (75%), while the sensitivity of bacteria against some antibiotics was (37.5%, 33.3% and 12.5%) for each of Gentamicin, Nitrofurantoin and Amikacin, respectively.
DNA was extracted from all isolates under study, and polymerase chain reaction was used to investigate the genes of virulence factors (tos A gene, csg A gene and 1 integrin class), the results showed that all isolates contained the mentioned genes.
On the other hand, the results of the genetic sequencing of the tosA gene showed that there is a substitution of different nucleotides between 10 isolates of the local E. coli bacteria and QJF95785.1 E. coli isolates, and they showed high transitional substitutions between nucleotides (C) that were replaced by nucleotides (T).
At the same time, this change did not affect the nucleotides in the histidine, so there was no change in the shape of the protein (hemolysin activation protein) produced by the tosA gene.