Pandrug-resistant isolate of Klebsiella pneumoniae causes less damage than drug-susceptible isolates in a rabbit model.

PURPOSE Bacterial infections induce a series of inflammatory responses and lead to longer hospital stays and increased mortality. In clinical work, we often find that infections caused by drug-susceptible isolates have a worse outcome than those caused by pandrug-resistant isolates. To goal of this study was to assess the impact of drug resistant in a rabbit model of Klebsiella pneumoniae infection. METHODS This study used a rabbit model of experimental bacteremia, challenged by susceptible (A), multidrug-resistant (B) and pandrug-resistant (C) isolates of Klebsiella pneumoniae. Mimimal inhibitory concentrations (MIC), leukocyte, TNFα, IL-17, and HMGB-1 levels and survival times were measured. RESULTS Mean survival times after challenge by isolates A, B and C were 10.5 ± 3.63, 12.7 ± 2.31 and 13.9 ± 0.32 days, respectively. Leukocytes levels after challenge with isolate C were lower compared with those after challenge with isolate A (p = 0.002). Blood counts of the offending pathogens and concentrations of TNFα, IL-17, and HMGB-1 were higher in the group challenged by isolate A in comparison with isolate B or C. Tissue bacterial load after animal death was significantly higher in rabbits of group A in comparison with isolates B and C. CONCLUSION Bacteremia induced by pandrug-resistant isolates is accompanied by less damage compared with bacteremia by drug-susceptible isolates. Rabbits infected with a pandrug-resistant isolate of K. pneumoniae survived longer and had a lower inflammatory response than did animals infected with drug-susceptible isolates.