High level of drug resistance by gram-negative bacteria from selected sewage polluted urban rivers in Addis Ababa, Ethiopia

OBJECTIVE: The aim of this study was to determine the level of drug resistance by gram-negative bacteria isolated from selected sewage polluted urban rivers in Addis Ababa, Ethiopia. RESULTS: From a total of 94 river water samples, 90 medically important gram-negative bacterial isolates were recovered to the species level. The predominant bacteria isolated were E. coli. 23 (26%) followed by K. pneumoniae 18 (20%), K. oxytoca 17 (19%). E. coli showed a high level of resistance to ampicillin 21 (91.3%), cefalotin, cefuroxime, ceftriaxone and cefepime 16 (70%). Both K. pneumoniae and K. oxytoca showed high resistance to ampicillin 16 (94%) and 17 (95%) respectively. Among identified bacterial species, most of them showed a multidrug-resistant pattern. Providential retigerri showed 100% multidrug resistance followed by P. alkalificiens (90%), E. coli (78%), M. morgani (75%), and C. frundi (60%).