Antibiotic sensitivity profile of Salmonella isolated from two slaughterhouses and human clinical cases

Abstract

<p>The antibiotic sensitivity of Salmonella strains isolated during the period 1996-98 from two industrial slaughterhouses of Northern Greece was detennined and compared with that of salmonellae isolated from human hospital cases during the period 1995-1997. For antibiotic sensitivity the disc agar diffusion method was used. Of 1874 samples obtained from the slaughterhouse environment (floors, worker's hands and their knives), pork carcasses, by-products (livers and plucks) as well as lymph nodes and caecal contents 178 (9.5%) were positive for Salmonella spp. The salmonellae belonged to 22 serotypes. S. derby, S. london and S. typhimurium represented 25.8%, 15.2%, and 10.7% of the serotypes respectively. Of the salmonellae 59%, and 4.5%, were resistant and 33%, and 4.5% were intermediate sensitive to Tetracyclin, and Streptomycin, respectively and 26.4%, 14.6%, 5.1%, 1.7% and 1% were resistant to Ampicillin, Sulfamethoxa>ole I Trimethoprim, Chloramphenicol, Gentamicin, and Tobramycin respectively. Of the S. typhimurium strains 47% were resistant to Ampicillin and 41.2% to Chloramphenicol. Seven of the 19 strains were DT I 04, isolated for the first time in Greece, and multiple drug resistant. Of all isolates 5.1% were resistant to Chloramphenicol, the use of which is prohibited in food animal veterinary practice. Of the 422 salmonellae isolated at the Hospital of Infectious Diseases in Thessaloniki during the period 1996-98 77.4% were S. enteritidis and 17.7% S. typhimurium. Of the salmonellae isolated during 1995-1997, 76-79 % were resistant to Ampicillin and 1.2-1.5% to Chloramphenicol. Many of S. typhimurium strains isolated from the slaughterhouses and human cases exhibited the same antibiotic sensitivity profile a fact indicative of a potential transfer of animal strains to humans. Salmonellae of the same serotype exhibited different antibiotic resistance profiles, an indication of the presence of different clones within the same serotype. No S. enteritidis was isolated in slaughterhouses.</p>