Abstract:
Introduction: The spread of drug resistant bacteria arises by different factors in the hospital
settings including environment, specifically sanitation and hygiene, inturn such places could be
visited by different arthropod vectors like houseflies there by microorganisms mechanically
picked by the houseflies. Having knowledge and understanding of such elements is essencial to
identify any modifiable interaction to decrease or intrupt the transmission of resistance from the
environment in to the hospital settings. Hence, this study aimed to determine antimicrobial
resistance pattern of gram negative bacteria isolated from houseflies in Jimma Medical Center.
Materials and Methods: A cross-sectional study was conducted from June 2021 to October
2021G.C. One hundred ninety-two houseflies were collected using a homemade sweep net.
Houseflies were picked by sterile forceps individually then kept in a sterile glass test tube
containing 1ml sterile normal saline then brought to Core research laboratory microbiology
unit, within 20 minutes. In the laboratory each tubes were well shaken to dislodge the bacteria in
to the the tubes. The concentrate was inoculated on to Mackonkey agar using sterile cotton swab
and gram-negative bacteria were further identified using biochemical tests. Antibiotic
susceptibility testing was performed by using the Kirby Bauer disk diffusion method and results
were interpreted according to European Committee on Antimicrobial Susceptibility Testing
(EUCAST) guideline . Data were analyzed using SPSS version 25.
Results: A total of 186-gram-negative bacterial isolates were recovered from 192 houseflies
collected in Jimma Medical center at different sites categorized into three: solid waste area,
liquid sewage, and garbage bins, and 64 houseflies were collected from each site. Among the
most isolated bacteria; Providencia species, Proteus species, and E.coli contributed 23.1%
(43/186), 19.4% (36/186), and 16.7% (31/186) respectively.The predominant 45.7% (85/186) of
the isolates were recovered from houseflies collected in solid waste areas and the least isolated
was from garbage bins, 18.3% (34/186). The percentage of isolates that were resistant to
ampicillin was 97.5% followed by cefuroxime to which 71.6% of the isolates were resistant.
There were 65.9% resistances to amoxicillin+clavulac acid, 62.9%, 61.3%, and 60.2% to
piperacillin, Trimethoprim+sulfamethoxazole, and cefotaxime respectively. The overall rate of
MDR (resistant to at least one agent in three or more antimicrobial class categories) among
isolated gram-negative bacteria was 86%. ESBL production was observed in: E.coli, Proteus
