Study On Biological Characteristics And Pathogenic Mechanism Of Enterobacter Sakazakii Isolated From Xinjiang

Objective:To analyze the biological properties and characteristics of invasiveness on suckling mice of Enterobacter sakazakii strains isolated from Xinjiang and explore the possible causative factors. Methods:The isolates were cultured in crystal violet neutral red bile glucose agar, tryptone soya agar, brain-heart medium, Enterobacter sakazakii chromogenic medium and casaminoacids yeast extract broth to observe the growth characteristics of different strains and evaluated for antimicrobial susceptibility testing recommended by Clinical and Laboratory Standards Institute.3 to 4 days old ICR suckling mice were inoculated intragastrically with 0.1ml of the toxin cultivation for 4 days and observed for another 3 days. Mice were euthanized with ethylether and then the entire intestinal tract, liver, spleen, kidney were removed for pathological section and microscopic examination after hematoxylin and eosin stain. Results:Different strains had different growth characteristics in different mediums. All of the isolates were resistant to imipenem and meropenem and were susceptible to at least 20 antibiotics. The I/C ratio of all isolates were less than 0.083, indicating enterotoxin negative, but the bacteria can still result in neonatal growth retardation and pathological changes in small intestine, ecolon, rectum, liver, spleen and kidney. Conclusion:Enterobacter sakazakii were less resistant to most antibiotics than other enterobacteria and the isolates of enterobacter sakazakii in Xinjiang have potential hazard.