A Mouse Model of Acinetobacter baumannii-Associated Pneumonia Using a Clinically Isolated Hypervirulent Strain

Autor: Harris, Greg, Kuo Lee, Rhonda, Lam, Christopher K., Kanzaki, Gregory, Patel, Girishchandra B., Xu, H. Howard, Chen, Wangxue
Zdroj: Antimicrobial Agents and Chemotherapy; May 2013, Vol. 57 Issue: 8 p3601-3613, 13p
Abstrakt: ABSTRACTAcinetobacter baumanniiis an important emerging pathogen in health care-acquired infections and is responsible for severe nosocomial and community-acquired pneumonia. Currently available mouse models of A. baumanniipneumonia show poor colonization with little to no extrapulmonary dissemination. Here, we describe a mouse model of A. baumanniipneumonia using a clinical isolate (LAC-4 strain) that reliably reproduces the most relevant features of human pulmonary A. baumanniiinfection and pathology. Using this model, we have shown that LAC-4 infection induced rapid bacterial replication in the lungs, significant extrapulmonary dissemination, and severe bacteremia by 24 h postintranasal inoculation. Infected mice showed severe bronchopneumonia and dilatation and inflammatory cell infiltration in the perivascular space. More significantly, 100% of C57BL/6 and BALB/c mice succumbed to 108CFU of LAC-4 inoculation within 48 h. When this model was used to assess the efficacy of antimicrobials, all mice treated with imipenem and tigecycline survived a lethal intranasal challenge, with minimal clinical signs and body weight loss. Moreover, intranasal immunization of mice with formalin-fixed LAC-4 protected 40% of mice from a lethal (100× 100% lethal dose) intraperitoneal challenge. Thus, this model offers a reproducible acute course of A. baumanniipneumonia without requiring additional manipulation of host immune status, which will facilitate the development of therapeutic agents and vaccines against A. baumanniipneumonia in humans.
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