Prevalence and antimicrobial resistance patterns in patients with blood stream infections: a four-year retrospective study at a tertiary healthcare center in Lebanon

Bloodstream infections (BSIs) are associated with high mortality, and their management is increasingly challenging. Therefore, this study aims to investigate the prevalence, epidemiological trends, and antimicrobial resistance patterns of BSIs at a tertiary care center over four years. A retrospective analysis was conducted on 8773 blood cultures tested for BSIs at SRHUH from January 1st, 2022, to October 30th, 2025. Data were collected from patients’ medical records. Antimicrobial susceptibility testing was performed using the VITEK 2 system. Only 6% of blood cultures were positive for bacterial infections. Gram-negative bacteria were the most prevalent type, with E. coli (42%) being the predominant pathogen. Both Gram-negative and Gram-positive species were significantly associated with gender and age groups. Over the four years, E. coli demonstrated high resistance rates to ampicillin (81–94%) and a progressive increase in resistance to second-generation Cephalosporins. Among Gram-positives, S. aureus showed high resistance to erythromycin/clindamycin, with no MRSA resistance observed. Regarding MDR bacteria, the prevalence of ESBL-producing E. coli decreased markedly, while CRAB increased during the study period. This study documents a high burden of AMR and a rising prevalence of MDR bacteria, highlighting the growing threat of antibiotic resistance in South Lebanon.