High Rate of Multidrug-resistance Among Clinical Isolates of Gram-negative Bacteria in Hospitalized Patients With Febrile Diseases in Central Ethiopia

Abstract

Background Infectious diseases are among the leading causes of death in many low-income countries such as Ethiopia. Without reliable local data concerning causative pathogens and antimicrobial resistance, empirical treatment is suboptimal. The objective of this study was the characterization of Gram-negative bacteria (GNB) as pathogens and their resistance pattern in hospitalized patients with infections in Central Ethiopia. MethodsPatients ≥1 year of age with fever admitted to the Asella Referral and Teaching Hospital from April 2016 to June 2018 were included. Blood and other appropriate clinical specimens were collected and cultured on appropriate media. Antibiotic susceptibility testing (AST) was performed using the Kirby-Bauer method and VITEK® 2. Species identification and detection of resistance-genes were conducted using MALDI-ToF-MS (VITEK® MS) and PCR respectively. ResultsOf 684 study participants, 54.2% were male and median age was 22.0 (IQR: 14-35) years. Blood cultures were positive in 5.4% (n=37). In other clinical samples, cultures were positive in 60.6% (20/33), 20.8% (5/24), and 37.5% (3/8) in swabs/pus, urine and other body fluids, respectively. Of 66 pathogenic isolates, 57.6% (n=38) were GNB, (39.4% (n=26) Gram-positive and 3.0% (n=2) were candida species. Among the isolated GNB, 42.1% (16/38) were E. coli, 23.7% (9/38) K. pneumoniae and 10.5% (4/38) P. aeruginosa. In total, 27/38 Gram-negative isolates were available for further analysis. Resistance rates were: ampicillin/sulbactam 92.6% (n=25), cefotaxime 88.9% (n=24), ceftazidime 74.1% (n=20), cefepime 74.1% (n=20), gentamicin 55.6% (n=15), piperacillin/tazobactam 48.1% (n=13), meropenem 7.4% (n=2), and amikacin 3.7% (n=1). The NDM-1 gene was detected in one K. pneumoniae and one A. baumannii isolate, which carried an additional OXA-51 gene. Genes for ESBLs were detected in 81.5% (n=22) isolates as follows: TEM 77.2% (n=17), CTX-M-1-group 68.2% (n=15), SHV-group 27.3% (n=6) and CTX-M-9-group 9.1% (n=2). Clinical treatment data revealed ineffective antimicrobial treatment in 13 of 18 (72.2%) patients.ConclusionWe report a high prevalence of ESBL-producing bacteria (81.5%) and carbapenem-resistance (7.4%), with more than half of the GNB carrying two or more ESBL genes resulting in sub-optimal empiric antibiotic therapy. These findings indicate a need for local and national antimicrobial resistance surveillance and strengthening of antimicrobial stewardship programs.