Background: Klebsiella pneumoniae is a cause of mild to life threatening infections. The bacterium poses an urgent public health threat because it has the potential to become resistant to virtually all categories of antimicrobials available. Multidrug resistant K. pneumoniae has caused nosocomial outbreaks in different continents. Little is known concerning the antimicrobial resistance profiles of K. pneumoniae in Ethiopia.

Objective: The aim of this study was to determine the antimicrobial resistance profiles of K. pneumoniae isolated from patients at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia.

Methodology: A cross-sectional prospective study was conducted from September 2018 to February 2019 on non-repetitive 132 K. pneumoniae isolated from patients. Identification of K. pneumoniae was done by examining gram stain, colony characterstics on MacConkey agar, 5% sheep blood agar and biochemical tests. Antimicrobial susceptibility testing was done by Kirby-Bauer disc diffusion technique using 21 antimicrobials. Extended spectrum b-lactamase (ESBL) and carbapenemase production was confirmed by combined disc test and modified carbapenemase inactivation method, respectively. Data was double entered using Epidata 3.1 and exported to SPSS version 25 software for analysis. P-value less than 0.05 was considered as statistically significant.

Results: From the total K. pneumoniae isolates high resistance was observed to cefotaxime and ceftriaxone 128 (97%), trimethoprim-sulfamethoxazole 124 (93.9%) and cefepime 111 (84.1%). High susceptibility was observed to amikacin 123 (93.2%), imipenem 107 (81.1%), meropenem 96 (72.7%) and ertapenem 93 (70.5%). Majority 130 (98.5%) of the isolates were multidrug resistant (MDR). Two isolates showed complete non-susceptibility to all antimicrobial agents tested. The magnitude of ESBL and carbapenemase production was 102/132 (77.3%) and 28/132 (21.2%). Of the total (n=30) non-ESBL producers, 73.3% were carbapenemase positive. Most (93.9%) of the isolates were positive for either ESBL, carbapenemase or both. Previous use of carbapenems was associated with carbapenemase production (P<0.001).

Conclusions and recommendations: All K. pneumoniae isolates showed appreciably high resistance to most of the tested antimicrobials. The magnitude of ESBL and carbapenemase production as well as MDR K. pneumoniae was very alarming in the study area. Of particular concern is that the majority of non-ESBL producers were carbapenemase producers. Therefore, strengthening antimicrobial stewardship programs together with effective infection control and antimicrobial surveillance practices is strongly recommended in Tikur Anbessa Specialized Hospital.

Key words: Klebsiella pneumoniae, extended spectrum b-lactamase, carbapenemase, multidrug resistance