Abstract:

Objective: To understand the serotype distribution and drug resistance to β-lactam antibiotics in Salmonella
isolated from animal derived foods in China. Methods: The slide agglutination and broth microdilution methods were used to
detect the serotype and resistant phenotype in 710 Salmonella isolates. Results: A total of 15 serotypes were identified among
these Salmonella isolates. The most common serotypes were S. pullorum, S. derby, S. give and S. fyris. The 710 strains
showed different resistance levels to 10 β-lactams and the resistance rate ranged from 13.66% to 58.03%. Meanwhile, 66.19%
of the strains showed multidrug resistance, and the drug resistance profile was very complex. In addition, no significant
correlation between resistance rate and year was observed, but overall the resistant rates increased with the extension of time.
All Salmonella serotypes were tolerant to the antibiotics differently, especially S. pullorum, S. enteritidis, S. salamae and
S. moers 100% of which had antibiotic tolerance. Conclusion: The resistance to β-lactams was serious in Salmonella isolates
from different serotypes. β-Lactams must be prudently used in veterinary clinical medicine.

Key words: animal derived foods, Salmonella, serotype, drug resistance