Trends in Enterobacteriaceae Resistance Patterns: A Nine-Year Retrospective Study From North Lebanon

Antimicrobial resistance (AMR) in Enterobacteriaceae poses a critical threat to global health, particularly in regions where antibiotic misuse and limited surveillance prevail. Intensive care units (ICUs) act as focal points for resistance emergence and dissemination. This study aimed to evaluate long-term resistance trends among clinically significant Enterobacteriaceae isolated from two hospitals in North Lebanon (2016-2024).

A retrospective analysis was conducted on 14,013 Enterobacteriaceae isolates obtained from Al Monla and Dar Al Shifa hospitals between 2016 and 2024. Identification was achieved using biochemical testing or MALDI-TOF mass spectrometry, and susceptibility testing followed EUCAST standards. No molecular characterization of resistance genes was performed. Data were analyzed using SPSS v23.0, applying Chi-square or Fisher's exact tests (p < 0.05).

Among 14,013 isolates, Escherichia coli (E. coli) was predominant (66.4%), followed by Klebsiella pneumoniae (K. pneumoniae) (12.4%), Proteus mirabilis (P. mirabilis) (5.5%), and Enterobacter cloacae (E. cloacae) (3.7%). Overall, β-lactam resistance remained widespread across species. In E. coli, carbapenem non-susceptibility increased from 2.7% to 4.8% (p < 0.001). P. mirabilis and E. cloacae exhibited significant increases in ESBL production (p = 0.006 and p = 0.007, respectively). K. pneumoniae showed fluctuating resistance trends with a mild decline in carbapenem resistance (p = 0.029). ICU isolates demonstrated higher ESBL and MDR rates than non-ICU isolates (p < 0.01), and hospital-acquired infections showed significantly higher resistance across most drug classes compared to community-acquired cases (p < 0.05).

Over the 9-year study period, Enterobacteriaceae isolates in North Lebanon demonstrated persistently high β-lactam resistance and increasing carbapenem non-susceptibility, particularly in E. coli. These findings underscore the importance of ongoing AMR surveillance and provide regional data that may support future evidence-based clinical and public health decision-making.