Researches concerning the sensibility to neomycin of some bacterial strains isolated from chicken.

Abstract

In this study we aimed to determine neomycin effect on Gram negative bacterial strains of the species Escherichia coli, Salmonella spp, Proteus spp and Klebsiella pneumoniae isolated from chickens with different diseases. Sensitivity to neomycin was also appreciated for standard reference strains: Bacillus anthracis 1190 R, Staphylococcus aureus 6538P, Bacillus cereus ATCC 14579, Pseudomonas aeruginosa ATCC 27853, E. coli ATCC 10536 and Salmonella enteritidis ATCC 13076. The experiment took place at the department of Microbiology of the Faculty of Veterinary Medicine Cluj-Napoca within October 2010 - March 2011, realizing the sensitivity tests to neomycin using the diffusimetric method. After testing a total of 33 bacterial strains, the resistance to neomycin was observed for 3 species (Escherichia, Proteus and Klebsiella) while for genus Salmonella no resistant strains were registered. Neomycin resistance was of 20% for strains of Escherichia, 25% for Proteus and 33.3% in those from genus Klebsiella. Sensitivity percentage of the tested strains ranged between 25% and 66.6%. Percentage of moderate sensitive strains ranged from 0 to 50%. Of the 6 standard reference strains tested, one was classified as sensitive (Staphylococcus aureus 6538P), three resistant (Pseudomonas aeruginosa ATCC 27853, E. coli ATCC 10536 and Salmonella enteritidis ATCC 13076) and two moderate sensitive (Bacillus anthracis 1190 R and Bacillus cereus ATCC 14579). The results obtained reveals that resistance to neomycin for the strains isolated from chickens varied from one bacterial species to another. Infections involving Escherichia coli, Proteus spp, Pseudomonas aeruginosa and Klebsiella pneumoniae should be considered more carefully, neomycin being recommended for the treatment only when the outbreak strains were tested and classified as sensitive to this antibiotic.