Prevalence of nosocomial infections and antibiotic resistance patterns in Iranian hospitals over five years.

Hospital-acquired infections (HAIs) are a global concern for patient safety and healthcare quality. In Iran, the prevalence of HAIs and rising antibiotic resistance among key pathogens pose significant challenges to patient care and healthcare systems. This study examines the prevalence of HAIs, resistance patterns, and infection rates in Iranian hospitals from 2019 to 2023. This cross-sectional retrospective study (2019–2023) analyzed HAIs across 38 hospitals in Isfahan Province, Iran, using data from the Health Deputy of Isfahan University of Medical Sciences, focusing on demographics, infection types, microbial pathogens, and device-associated infections. Infection proportion and associated mortality rates for the specified infection types were calculated per 1,000 patient-days using data sourced from diverse clinical settings. Pathogen identification employed microbiological and molecular techniques, while antibiotic resistance testing adhered to Clinical and Laboratory Standards Institute guidelines. Statistical analysis using SPSS and R Studio evaluated infection prevalence, microbial trends, and resistance patterns stratified by demographics and locations. Between 2019 and 2022, the proportion of patients with HAIs remained stable at approximately 5%. The most common HAIs were urinary tract infections (UTIs), pneumonia, and surgical site infections, caused by pathogens such as Acinetobacter baumannii, Klebsiella pneumoniae, and Escherichia coli, which exhibited significant resistance to carbapenems and third-generation cephalosporins. Infection rates varied across regions and healthcare facilities, reflecting notable geographical disparities. Intensive care units and transplant units had the highest rates, while psychiatry, ENT, and ophthalmology departments had fewer cases. Elderly patients (65+) were most affected, with men prone to ventilator-associated pneumonia and women to UTIs. Alarmingly, resistance among Gram‑negative pathogens has increased markedly, exceeding 70% for several major antibiotic classes in 2023. Acinetobacter spp. displayed the highest resistance levels, including ceftazidime 94.9% (95% CI: 93.4–96.4), fluoroquinolones 90.9% (95% CI: 88.8–93.0), aminoglycosides 84.9% (95% CI: 82.3–87.4), and carbapenems 93.3% (95% CI: 91.5–95.1), while susceptibility to colistin remained largely preserved (3.8% resistance; 95% CI: 1.6–8.3). Klebsiella spp. also exhibited high resistance to third‑ and fourth‑generation cephalosporins 88.0% (95% CI: 86.3–89.6) and β‑lactam/β‑lactamase inhibitor combinations 86.6% (95% CI: 84.0–89.0). In contrast, Escherichia coli and Pseudomonas aeruginosa showed comparatively lower resistance across most antibiotic categories. The study underscores the need for enhanced infection control, antibiotic stewardship, and targeted strategies to reduce HAIs and resistance. These strategies aim to improve patient outcomes and alleviate healthcare burdens in Iranian hospitals.