ANTIBIORESISTANCE OF ESCHERICHIA-COLI STRAINS ISOLATED IN MOROCCO FROM CHICKENS WITH COLIBACILLOSIS

Two hundred and fifty eight isolates of Escherichia coli were made fro m autopsied chickens showing lesions of avian colibacillosis. Antibiog rams showed high levels of resistance (greater than 40%) to sulphonami des (SSS), oxytetracycline (OT), trimethoprim + sulphamethoxazole (STX ) and chloramphenicol (C). Medium frequencies of resistances (from 15 to 40%) were noted for streptomycin (S), spectinomycin (SPT), nalidixi c acid (NA), oxolinic acid (OA), flumequine (UB) and enrofloxacine (EN R). For ampicillin (AM),gentamicin (GM), nitrofurans (FT), colistin (C S) and rifampin (RA) the frequencies of resistance were low (less than 15%). A linked resistance was observed for the 4 quinolones. A signif icant percentage of isolates (82.5%) were resistant to at least 2 anti microbial agents. The most frequent antibiotypes were: C.OT.SSS.STX (4 .65%), C.OT.SSS.STX.OA.NA.UB.ENR (4.65%), AM.S.C.OT.SSS.STX (4.26%) an d OT.SSS.STX (3.87%).