ISSN: 1813-0410

Keywords : Staph

Susceptibility of Staphylococcus aureus and Escherichia coli isolated from fish to some antibiotics

journal of kerbala university, Volume 5, Issue 2, Pages 221-227

Twenty five Tenualosa ilisha fish were collected during September,2008. Staph. aureus and E. coli were isolated from gills of these fishes after they had grown on specific culture media. Staph. aureus was identified according to the morphological characteristics and coagulase test, whereas E. coli identified according to the morphological characteristics and IMViC tests, then the antibiotic susceptibility test was done against 18 antibiotics.
The results showed that the inhibiting zones were 29,28.5 mm for Gentamicin CN and Ciprofloxacin CIP against Staph. aureus . Ampicillin AM, Carbenicillin PY, Cefamandole MA, Chloramphenicol C, Roxithromycin ROX, Cloxacillin CX, Spiramycin SP, Kanamycin K, Methicillin ME, Erythromycin E, Nalidixic acid NA, Streptomycin S and Vancomycin VA didn't show any activity towords this bacterium . The highest inhibition percentage of Staph. aureus in broth were (92.59, 84.1,63.1)% for Gentamicin CN, Ciprofloxacin CIP and Piperacillin PRL respectively ,whereas the lowest inhibition percentage were (4.06,5.12,14.31)% for antibiotic Ampicillin AM, Cloxacillin CX and Carbenicillin PY respectively.
E. coli were sensitive to Moxifloxacin MXF and Azithromycin AZM ; inhibiting zones were 28.5,25.5 mm respectively, while the antibiotic PY showed less activity, ( 7mm) whereas the S, ME ,NA,CX,MA,AM and VA had no effect on the bacterium .The highest inhibition percentage were (96.1,83.7,79)% for MXF,AZM,and CIP respectively whereas the lowest inhibition percentage were (3.7, 5.06,8.3)% for AM,CX and ME respectively.
The study concluded that the best antibiotic which showed activity to wards Staph. aureus and E. coli were CN,CIP and MXF while the antibiotics VA,NA,ME,MA,AM,AM and CX didn't show any activity when they were used.