Urinary tract infections (UTIs) are a global health concern, with over 150 million cases annually, primarily caused by Escherichia coli. Due to anatomical differences, females, especially children and postmenopausal women, are four times more susceptible. Crucially, E. coli has developed widespread antimicrobial resistance (AMR), including resistance to broad-spectrum agents and the emergence of Extended-Spectrum Beta-Lactamase (ESBL)-producing strains. This retrospective study analyzed hospital records from 95 female patients with positive urine cultures at Siblin Governmental Hospital in 2024. Patients were stratified into three age categories: children (≤18 years), adults (18–64 years) and elderly patients (>64 years). Statistical analysis using SPSS focused on descriptive resistance patterns and differences across age groups. Overall, cephalothin (85.7%) and cefaclor (78.49%) exhibited the highest resistance rates. Conversely, tigecycline (97.22%) and ertapenem (91.67%) showed the highest susceptibility. Resistance patterns varied significantly by age. For instance, elderly patients showed high resistance to agents like Augmentin (52.5%) and cefixime (66.1%), while the pediatric group (≤18 years) displayed exceptionally high resistance to cefixime (90.0%). E. coli isolates show high resistance to conventionally used antibiotics, complicating UTI treatment. These findings highlight the need for continuous local surveillance, particularly focusing on third-generation cephalosporins and beta-lactamase production. Ultimately, age is a critical factor that must be considered when determining empirical antibiotic therapy for UTIs.

Background: Respiratory tract infections (RTIs) and urinary tract infections (UTIs) are among the most common infections in humans. It is estimated that millions of deaths occur each year worldwide due to these infections. Pseudomonas aeruginosa (P. aeruginosa), in particular, represents a public health threat since it has a high ability to acquire resistance to different antibiotic classes. The aim of this study was to determine the prevalence and antimicrobial resistance patterns of P. aeruginosa isolates from patients with RTIs and UTIs in Lebanon. Methods: This retrospective study was performed during 2020–2022 and 2024–2025. Samples were collected from both inpatients and outpatients, where identification and isolation of bacteria were performed along with antibiotic susceptibility testing. Results: The overall prevalence of P. aeruginosa isolates in RTI cases over the study period was 10.9%, and that of UTI cases was 1.3%. The general antimicrobial resistance profile of P. aeruginosa isolates from RTI and UTI cases showed the highest resistance for Piperacillin–Tazobactam and Aztreonam, respectively. For RTIs, antibiotic resistance decreased from 48.1% in 2020 to 36.7% in 2025 and increased from 16.7% to 19.4% for UTIs. Conclusions: According to our research, P. aeruginosa with low antibiotic susceptibility is frequently found in isolated samples, highlighting the significant challenge in treating severe infectious illnesses. To choose focused and efficient antibiotic therapy for RTIs and UTIs and to stop the emergence of multidrug-resistant (MDR) bacteria, it is essential to accurately identify the pathogenic microorganisms and their antibiotic susceptibility patterns.