Urinary tract infections (UTIs) caused by Escherichia coli represent a significant public health concern due to the high virulence and antimicrobial resistance exhibited by these pathogens. This study aimed to analyze the phylogenetic diversity and antibiotic resistance profiles of Uropathogenic E. coli (UPEC) strains isolated from UTI patients in Algeria, focusing on virulence factors such as extended β-lactamase (ESBL) production, biofilm formation, and hemolytic activity. Phylogenetic grouping of 86 clinical imipenem resistant E. coli isolates showed the prevalence of group B2 (48.9%), followed by groups E (22.1%), unknown (12.8%), A (8.1%), and B1 (4.7%), and Clade I, D, Clade I, or Clade II (1.2%). The highest resistance rates were observed towards amoxicillin (86.04%), ticarcillin (82.55%), piperacillin (73.25%), nitrofurantoin (84.88%), and trimethoprim-sulfamethoxazole (51.16%). Notably, 69.8% of UPEC strains were multidrug-resistant (MDR) and 23.2% were extensively drug-resistant (XDR). Additionally, 48.9%, 42%, and 71% of strains demonstrated ESBL production, hemolytic activity, and weak biofilm production, respectively. Continuous monitoring and characterization of UPEC strains are essential to track the spread of the most resistant and virulent phylogenetic groups over time, facilitating rapid therapeutic decisions to treat infections and prevent the emergence of new resistant organisms, helping choose the most effective antibiotics and reducing treatment failure.

The antibacterial activity of 18 phenolic compounds, including flavonoids and phenolic acids, against organisms of Escherichia coli, Klebsiella pneumoniae, and Proteus vulgaris that are resistant to several drugs was assessed in this study using the agar diffusion method. The strain’s strong resistance was confirmed by antibiotic susceptibility testing, which used fourteen drugs and only found inhibition zones for five of them. Out of the polyphenols, four compounds were effective against P. vulgaris, five against K. pneumoniae, and twelve against E. coli bacteria. The greatest inhibitory zone (18.75 ± 0.25 mm) against E. coli was shown by propyl gallate, an ester of gallic acid. Activity was significantly impacted by structural changes. Propyl substitution increased antibacterial activities across all strains, while methoxy substitution decreased them. The antibacterial effectiveness was reduced by the hydroxylation of flavonoids and the C3–C4 dihydroxylation of cinnamic acid. Propyl gallate primarily had antagonistic effects, while combination experiments demonstrated additive, synergistic, and antagonistic interactions. Propyl gallate (ΔG = −7.5 kcal/mol) exhibited substantial binding affinities with TEM-1 and NDM-1 β-lactamases via hydrogen and hydrophobic interactions, according to molecular docking. These results demonstrate propyl gallate as a viable antibacterial adjuvant option and validate the structure–activity relationship of phenolic compounds.

Background. Antibiotic resistance is a growing global health challenge, complicating the management of infections. Aminoglycosides are increasingly associated with resistance, raising the risk of clinical complications and mortality in severe infections. This study aimed to characterize the epidemiological profile of 135 aminoglycoside-resistant clinical strains collected in Setif between 2021 and 2023. Methods. Antibiotic susceptibility testing was performed according to EUCAST guidelines, and phenotypic assays were conducted to assess key virulence traits, including biofilm formation and enzyme production. Results. Aminoglycoside resistance was more frequently observed in female patients (55.6%) and was found to be predominant among adults (68.1%). Urinary tract infections represented the main clinical presentation (76.3%), with Escherichia coli being the most common isolate (40.7%). High resistance rates were detected for amoxicillin (83%), amoxicillin–clavulanic acid (80%), cephalexin (74.8%), cefixime (71.1%), trimethoprim–sulfamethoxazole (74.8%), and gentamicin (72.6%). Conversely, chloramphenicol (53.3%), imipenem (47.4%), amikacin (47.4%), and piperacillin–tazobactam (31.1%) remained comparatively more effective. Multidrug resistance involving seven antibiotics occurred in 25.6% of isolates, with notable cross-resistance patterns between gentamicin and β-lactam antibiotics (5 out of 22). Genotypic analysis showed that 43% of isolates carried at least one β-lactamase gene, whereas 9.6% harbored a qnr determinant. Regarding virulence factors, isolates with low biofilm-forming ability were found to be the most common (62.96%). Conclusion. In conclusion, this study revealed substantial variations in aminoglycoside resistance in Setif, shaped by demographic, clinical, and bacteriological factors.

Background: Escherichia coli is the leading cause of urinary tract infections (UTIs), and the increasing prevalence of antimicrobial resistance represents a major public health concern. The dissemination of multidrug-resistant uropathogenic E. coli (UPEC), frequently harboring transferable resistance determinants, poses an urgent clinical challenge. Methods: This study investigated the prevalence of β-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaCMY, and blaDHA) and plasmid-mediated quinolone resistance genes (qnrA, qnrB, qnrC, qnrD, and qnrS) in 86 imipenem-non-susceptible UPEC isolates using multiplex and single PCR assays. Gene distribution and co-occurrence were examined across E. coli phylogenetic groups, and pairwise associations were evaluated using correlation analysis. Principal component analysis (PCA) was applied to explore global relationships between antibiotic susceptibility profiles, extended-spectrum β-lactamase (ESBL) phenotype, and resistance determinants. Results: Overall, 74.4% of imipenem-non-susceptible isolates carried at least one β-lactamase gene. blaTEM was the most prevalent (62.8%), followed by blaCMY II (12.8%). blaSHV, blaCTX-M group I, and blaCTX-M group II showed comparable prevalence (10.5% each). The B2 phylogroup showed the greatest diversity of β-lactamase profiles, with phylogroup E representing the second most frequent reservoir. Among quinolone resistance genes, qnrB was the most prevalent (20.9%), followed by qnrD (5.8%), qnrS (4.7%), qnrA (3.5%), and qnrC (1.2%). All qnrC-positive isolates were resistant to all tested quinolones. No statistically significant associations were observed between β-lactamase genes and qnr genes. Significant within-class correlations were detected for blaCTX-M group II–blaCMY II (φ = 0.893, q = 9.33 × 10–9) and qnrC–qnrA (φ = 0.57, q = 0.374). Conclusions: A high prevalence of β-lactamase and qnr determinants was observed among imipenem-non-susceptible UPEC, primarily driven by blaTEM and qnrB, frequently detected in B2 isolates. The co-occurrence and correlation of multiple resistance genes highlight the complexity of resistance architectures and underscore the need for ongoing molecular surveillance and strengthened antimicrobial stewardship to limit the dissemination of resistant UPEC.