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 African Journal of Microbiology Research Vol. 6(49), pp. 7525-7533, 25 December, 2012 Available online at http://www.academicjournals.org/AJMR DOI: 10.5897/AJMR12.2084 ISSN 1996-0808 ©2012 Academic Journals Full Length Research Paper Antimicrobial resistance of Salmonella spp. strains isolated from hamburgers 

Jorge Luiz Fortuna1 *, Elmiro Rosendo do Nascimento2 and Robson Maia Franco2 

1Universidade do Estado da Bahia (UNEB). 

Laboratório de Microbiologia. Campus X. Curso de Ciências Biológicas. Av. Kaikan, s/n – Universitário. Teixeira de Freitas-BA. CEP: 45.995-300. Brazil. 2Universidade Federal Fluminense (UFF). Faculdade de Veterinária. Niterói, RJ, Brazil.

Susceptibility of 45 Salmonella spp. strains isolated from beef and beef and chicken hamburgers was evaluated. Twelve antimicrobial drugs were used in the disc diffusion method. A cladogram was constructed and similarity across strains was assessed. Strains were susceptible to co-trimoxazole, chloramphenicol, amikacin, tetracycline and gentamicin (91.11, 91.11, 84.44, 80.0, 77.78%), though resistance was detected against cefotaxime, ampicilin, cephalothin, ceftriaxone, cefotixin, ceftazidime, and aztreonam (88.89, 71.11, 68.89, 53.33, 48.89, 42.22, 35.56%). The least effective antimicrobial drug was cefotaxime (88.89%). A high percentage of multiresistant Salmonella spp. strains was observed. This raises concerns as to the high risk for salmonellosis in humans, when these food items are consumed underdone, or by cross-contamination during preparation. Another important aspect in terms of public health is that these infections may become even more severe due to the lower efficacy of antimicrobials in treatments, both in humans and animals. 

Key words: Resistance, susceptibility, antimicrobial, Salmonella, hamburger, cladogram.