Epidemiology, Clinical Features, Outcomes, and Antimicrobial Resistance Patterns of Enterobacteriaceae Bacteremia in a Tertiary Care Hospital of Peshawar

Abstract

Objective: To determine the frequency, antimicrobial resistance patterns, clinical outcomes, and predictors of in-hospital mortality with Enterobacteriaceae bacteraemia.

Methodology: This retrospective study was conducted at Rehman Medical Institute, Peshawar, over one year. Patients from all age groups with Enterobacteriaceae (excluding Salmonella spp.) bacteraemia presenting to hospital from March 2024 to March 2025 were included. Bacterial identification and antibiotic susceptibility testing followed CLSI guidelines. Clinical and demographic data were collected and analyzed by SPSS 27.

Results:  Of 569 positive blood cultures, 154 (27.1%) yielded Enterobacteriaceae growth. Of 154 patients, 91 (59.1%) were male. The median (IQR) age of participants was 43 (55) years. The most common focus of infection was the respiratory tract (75, 48.7%). Around 57 (37.0%) cases required ICU admission, while 49 (31.8%) were mechanically ventilated and 55 (35.7%) received inotropic support. Meropenem was the most frequently prescribed empirical antibiotic (37.8%). Klebsiella pneumoniae (52.6%) was the commonest isolated pathogen. High resistance was observed for amoxicillin (97.8%), ceftriaxone (78.8%), and ciprofloxacin (76.9%). While 35.7% of pathogens were resistant to amikacin and 43.5% were resistant to meropenem. Mortality (26.90%) was significantly associated with age >60 years, malignancy, chronic kidney disease, altered consciousness, use of inotrope, and mechanical ventilation. Independent predictors of death included Age >60 years (OR 10.6), altered consciousness (OR 19.2), inotrope support (OR 35.7), mechanical ventilation (OR 142.9), extended-spectrum beta-lactamase (ESBL) strains (OR 8.3), and coagulation abnormality (OR 7.3).

Conclusion: Multidrug resistance among Enterobacteriaceae bacteremia isolates is alarmingly high. Advanced age, altered consciousness, haemodynamic instability, ventilator support, and ESBL strains were strongly associated with in-hospital mortality.

Keywords: Antibacterial Agents, Bacteremia, Drug Resistance, Enterobacteriaceae Infections, Hospital Mortality