The investigation of adrenal involvement in carbapenem resistant Acinetobacter baumannii sepsis: experimental mouse model.

Abstract

In the last years, incidence of carbapenem resistant Acinetobacter baumannii sepsis is increasing with high mortality. However, it is not clear whether this is due to inadequate antimicrobial choice or a more severe clinical course. We aimed to evaluate the inflammation and adrenal involvement in the carbapenem resistant A. baumannii by using experimental mouse model sepsis. Balb/c female mice were randomly put into control and three sepsis groups (A. baumannii susceptible to carbapenem-CSAB-, A. baumannii resistant to carbapenem-CRAB-, Escherichia coli). A total of sixty mice were included in this study with each group having 15 mice. Mice were sacrificed 72 h after bacterial inoculation, and blood was taken from each mouse for the assessment of cytokines and corticosterone. Both adrenal glands were dissected; one was used for culture and the other was used for histopathological examination. Bacterial loads of organs were calculated as CFU/g. The histopathological changes, bacterial levels in adrenal and cytokine and corticosterone levels were assessed and compared among the groups. The bacterial level was higher in E. coli (108, 45 ±30, 55 log10 CFU/g) (mean±SD) than other sepsis groups. The lowest level of corticosterone was observed in the E. coli group (p < 0.001). TNF alpha level was highest in the CRAB and E. coli group and this difference was statistically significant than control group (p < 0.05). The IL-6 level in CRAB was significantly higher than the control group (10, 20 pg/mL). The adrenal gland congestion was significantly severe in all the sepsis groups compared to the control. In the group comparison, congestion was significantly more severe in the E. coli group than in CSAB and CRAB groups. Adrenal involvement and inflammatory reactions are seen in E. coli sepsis and in CRAB sepsis. These findings will be focused on in future clinical trials.