Abstract
Studies were carried out to investigate the incidence of multiple antibiotic resistance among Escherichia coli (total 152) isolated from
poultry in Karachi to eight commonly used antibiotics: ampicillin (A), chloramphenicol (C), gentamycin (G), kanamycin (K),
neomycin (N), polymyxin B (P), streptomycin (S) and tetracycline (T) at the levels of 50, 100 and 500 μg/ml. Results are showing the
number of resistance strains with different patterns of antibiotic resistance at different levels. A comparison of antibiotic resistance to
different number of antibiotics and the frequency of resistance to individual antibiotic at different levels is also reported. The highest
frequency of resistance was found against tetracycline whereas the lowest frequency of resisatnce was against gentamycin. Thirty R
plasmids were isolated from the resistance starins and will be reported elsewhere.
