Prevalence of multidrug resistant gram-negative bacteria and associated factors among gram-negative blood culture isolates at Tikur Anbessa Specialized Hospital: a retrospective study.

backgroundThe rising incidence of multidrug-resistant (MDR) gram-negative bacteria causing bloodstream infections (BSI) is a significant concern, particularly in Sub-Saharan Africa, where inadequate control over antibiotic access, poor antimicrobial stewardship, and weak infection prevention measures worsen the issue. This study aims to assess prevalence, bacteriologic profile, and associated risk factors of MDR-gram negative isolates and carbapenem resistant gram-negative BSI admitted patients of Tikur Anbessa Specialized Comprehensive Hospital (TASH) a tertiary hospital in Adiss Ababa that uses disc diffusion method for antimicrobial susceptibility testing.

methodsA single-center cross-sectional retrospective study was conducted in the medical wards of TASH from September 1, 2021, to September 1, 2023. The gram-negative blood isolates of 137 patients were compared for clinical profiles, demographics, comorbidities, admission sites, sepsis or septic shock, use of instrumentation, surgical procedures, prior antibiotics, hospital stay length, and immunosuppressive therapy as risk factors for gram-negative BSI. Multidrug resistance and carbapenem resistance rates and associated risk factors were determined. Antimicrobial susceptibility data were retrieved, and clinical parameters were retrieved from electronic medical databases and patient medical cards. Data analysis was performed using SPSS Version 26.

resultsA total of 137 gram-negative blood culture isolates were identified during the study period. Most blood cultures were from the Emergency Room (29.2%). Prior antibiotic exposure was recorded in 25% of participants. Escherichia coli (33%) and Klebsiella pneumoniae (30.1%) were the most common isolates. Carbapenem resistance was 58.1%. The total MDR rate was 111 gram-negative blood culture isolates(81%). Carbapenem resistance rates were 77.4% for Klebsiella pneumoniae and 47.8% for Escherichia coli. Risk factors for MDR gram-negative BSI included hematologic malignancy (AOR = 1.4, 95% CI = 1.12-4.27), Enterobacterales (AOR = 4.4, 95% CI = 1.57-34.18), and ICU admission (AOR = 2.1, 95% CI = 1.24-16.56). Risk factors for carbapenem resistance included immunosuppressive treatment (AOR = 2.1, 95% CI = 1.24-3.78), prior Cefepime use (AOR = 4.9, 95% CI = 1.27-41.24), CNS shunt devices (AOR = 12.4, 95% CI = 4.26-22.56), and Acinetobacter spp. infection (AOR = 4.2, 95% CI = 2.19-14.63).

conclusionsThe study highlighted the growing prevalence of MDR and Carbapenem resistant gram-negative bloodstream infections in a hospital with limited resources. Our findings emphasize the urgent need for effective antimicrobial surveillance and infection control measures throughout the country.