Background: Colistin is considered as last line in treating infections caused by carbapenem-resistant Enterobacteriacae (CRE). Resistance of E. coli against colistin comprise a major public health threat. Uncontrolled use of colistin and other antimicrobials in the poultry industry in Gaza strip probably accelerated the emergence of resistance to colistin and the spread to human.
Objective: The main objective of this study is to determine the occurrence of colistin resistance in isolates of E. coli from chicken fecal materials in Gaza strip, Palestine
Methods: One hundred and ten chicken litter samples were collected from different poultry farms (Gaza and middle governorates). All samples were cultured onto Eosin Methylene Blue and MacConkey Agar plates. E. coli were identified biochemically. Disk diffusion method was used to determine the antimicrobial susceptibility for 11 antimicrobial agents (Ceftriaxone, Chloramphenicol, Ampicillin, Co-trimazol, Meropenem, Amikacin, Norfloxacin, Nalidixic acid, Neomycin, Cephalothin, and Colistin).
Result: There were wide variations in the susceptibilities of the different E. coli isolates to these antimicrobials. Resistance to Ampicillin was detected in all 110 (100%) isolates, followed by Cephalothin (86.4%), Cotrimazol (67.3%), Nalidixic acid (52.7%), Chloramphenicol (43.6%), Ceftriaxone (30.9%), Neomycin (17.3%), Norfloxacin (15.5), Colistin in 16 (14.5%), Meropenem in 5 (4.5%), and Amikacin (0.9%). Of the tested isolates, 76.4% (84) were multidrug resistant (MDR).
Conclusion: Phenotypic resistance to colistin sulfate was found in 16 (14.5%) isolates. Resistance to meropenem was found in 5 (4.5%) isolates from the total of 110 isolates and 76.4% (84) were MDR. This requires immediate action by the concerned authorities to regulate and monitor the use of antimicrobials in the poultry industry.