Molecular detection of the expression of some adhesion-related genes in uropathogenic escherichia coli and their relationship with antibiotic resistance in clinical isolates from patients from Baghdad and Iraq

Uropathogenic Escherichia coli (UPEC), which causes urinary tract infections (UTIs), is a common cause of UTI morbidity and is the bacterium most commonly responsible for urinary tract infections. Several virulence factors (VFs) enable UPEC to infect and harm the host. β-lactamases represent the most common mechanism of resistance to β-lactam antibiotics for gram-negative bacteria, especially in Escherichia coli. In this study, we aimed to evaluate the effects of hlyA, fimH, tosA and papG gene expression and their association with antibiotic resistance in uropathogenic Escherichia coli. For this purpose, 150 mid-stream urine samples were collected from patients of both sexes and different ages with various clinical symptoms of UTI admitted to Baghdad Teaching Hospital and Ghazy AL-Hariri hospital in Baghdad/Iraq between January 2023 and April 2023. Isolates were identified using different diagnostic methods according to their morphological characteristics on Gram staining and culture media (MacConkey agar, blood agar and VITEK-2 system). Molecular methods were performed on isolated bacteria using PCR amplification and reverse transcription quantitative PCR (RT-qPCR) for the detection and expression assessment of hlyA, fimH, tosA and papG genes. Initial results from 150 urine samples showed that 55 (36.66%) samples had growth, 35 (23.33%) were identified as E. coli bacteria, 20 (13.33%) were identified as Gram-positive bacteria and 95 (63.34%) had no growth. When 35 E. coli isolates were tested for 20 antibiotic disks, the highest level of resistance was found to Ticarcillin (97.14%), followed by Ampicillin, Piperacillin and Amoxicillin (91.43%), Ceftriaxone and Cefpodoxime (88.57%), Norfloxacin (85.71%) and Trimethoprim/sulfamethoxazole (82.86%). These isolates showed moderate resistance to Levofloxacin (74.29%), followed by Aztreonam (68.57%), Ticarcillin/clavulanic acid and Ciprofloxacin (60%), Cefepime (54.29%) and Piperacillin/Tazobactam (51.43%). In contrast, the lowest level of resistance was observed against Ceftazidime and Amikacin (48.57%), followed by Tobramycin (40%), Gentamicin (31.43%), Imipenem (25.71%) and Meropenem (8.57%). Of the identified isolates, 35 were subjected to further molecular study, screening for frequency of detection and evaluating the expression of fimH, tosA genes, hlyA gene and papG gene. The results showed that out of a total of 35 isolates, 33 isolates (94.30%) were positive for fimH and papG genes at a higher frequency, 20 isolates (57.10%) were positive for hlyA gene and 7 isolates (20%) were positive for tosA gene at a lower frequency. The expression of HlyA, TosA, FimH and PapG genes increased during urinary tract infection, with the highest value recorded 44.341-fold in the HlyA gene. This was followed by TosA gene 24.115-fold, FimH 20.272-fold and PapG 14.466-fold, respectively. The mean values of E. coli and ct of the genes in the study, the highest hlyA was determined in papG, TosA and FimH genes, respectively. Sequences of hlyA gene for 6 isolates, fimH gene for 5 isolates and papG (atpC) gene for 7 isolates are presented in NCBI GenBank sequence database under accession numbers Escherichia coli (PQ285076, PQ285077, PQ285078). In this study, the association between papG gene and resistance to Imipenem (p-value 0.013) and the positive association between hlyA gene and resistance to Cefepime (p-value 0.05) were investigated. Furthermore, the presence of tosA gene was associated with resistance to Amoxicillin (p-value 0.035), Norfloxacin (p-value 0.0001) and Trimethoprim/sulfamethoxazole (p-value 0.002). In addition, resistance was detected between the fimH gene and piperacillin (p-value 0.031). In conclusion, the female group was associated with a higher incidence of bacterial infections, especially urinary tract infections caused by E. coli, compared to the male group. The higher frequency of fimH and papG genes among the E. coli isolates in this study suggests that these genes play an important role in the pathogenesis of urinary tract infections. The bacterial isolates in the study exhibited significant resistance rates to different antibiotics. This makes treatment more difficult and is seen as a serious problem for healthcare institutions. The higher frequencies of ESBL phenotype among E. coli isolates include fimH, hlyA and papG genes, suggesting that there may be direct and indirect relationships between these genes and ESBL phenotype, making these isolates more virulent than others. There is also an association between virulence genes and the development of resistance to certain types of antibiotics. This suggests that many factors such as coexistence, virulence, genetic mobility and resistance agents may provide an important synergism between the presence of these genes and the development of antibiotic resistance in E. coli isolates.