Rate of induction of resistance in Fecal E-coli against cefquinome as compare to ceftriaxone after continuous passage in vivo


The study was conducted to evaluate the development of resistance for fecal E. coli against third and fourth generations of cephalosporins . This bacteria was chosen because they represent the pool of resistance elements that are available for transfer to other bacterial species including pathogens.Three groups of 5 (mice) were used. 89.25µg/Kg) of ceftriaxon and(12.5µg/Kg) of cefquinome, were given a sub therapeutic dose orally for the first and second groups respectively. While the third group were given distilled water only as a control. Then isolation, purification and identification of fecal E-coli from GIT was done. Morphological and biochemical tests had been used to make sure that isolated bacteria was E.coli. It has been observed that the mean value minimum inhibitory concentration (MIC) of the isolated bacteria from both of first and second groups was compared with the control group.MIC of both antibacterials in comparison with the control group which were 1.18 , 1.37µg/ml for ceftriaxone ,cefquinome respectively. While the MIC values for ceftriaxone and cefquinome were 16.00 and 4.6 µg/ml respectively .this means that the significancy (P<0.05) was 13.55 folds and 3.35 folds in the third and fourth generation generations respectively in comparison with the control of each antibacterial .We concluded that antibiotic resistance may not be only a consequence in pathogenic bacteria but also in normal flora which could contribute this resistance to other microorganism.