Drug resistance of major Salmonella of different serotypes other than Salmonella typhoid in China

Objective To understand the common antibiotic resistance of major Salmonella of different serotypes other than Salmonella typhoid in China and provide reference for the clinical antibiotic use and evidence for the prevention and treatment of Salmonella infection. Methods The drug susceptibility test of 219 Salmonella strains, including S. agona, S. weltevreden and S. senftenberg strains isolated in China from 2006-2011 to 14 antibiotics was conducted with broth microdilution method, the minimum inhibition concentration was obtained and interpreted according to CLSI standard. Results All the isolates were sensitive to the 4th generation cephalosporin. The sensitive rates to several antibiotics, including the 3rd generation cephalosporins (cefotaxime, ceftazidime), ampicillin, ciprofloxacin, trimethoprim, chloramphenicol and tetracycline, ranged from 97% to 99%. The sensitive rates to streptomycin and nalidixic acid were 93.61% and 91.32% respectively. The sensitive rate to sulfamethoxazole was 85.39%. Eight isolates were resistant to multi antibiotics, in which 6 belonged to S. agona, two showed ACSSuT resistance and 1 produced extended spectrum beta-lactamase. The drug susceptibility of 3 serotype Salmonella to sulfamethoxazole was significantly different (35.09% resistant in S. agona, 14% resistant in S. senftenberg and 100% sensitive in S. weltevreden). Conclusion The three serotypes of Salmonella showed different resistance to 14 tested antibiotics and the drug resistance and multi-drug resistance varied among these strains, but the overall sensitive rate to 14 antibiotics was high, indicating the empirical treatment could be conducted with common antibiotics except sulfamethoxazole when acute infection with Salmonella occurred.