title: Acid aspiration provokes the pneumonia caused by multidrug-resistant Acinetobacter baumannii in BALB/c mice.
abstract: OBJECTIVE
  To determine whether acid aspiration provokes the development of multidrug-resistant Acinetobacter baumannii (MDRAB) pneumonia in its host.
  
  
  METHODS
  Groups of mice were inoculated intratracheally (IT) with 50 μl of 0.1N HCl and 1 × 10(8) colony-forming units (CFU) Ab396 (A+Ab group), or 50 μl of 0.1N HCl and 20 μl of 0.9% saline (A+S group), or 20 μl of 0.9% saline and 1 × 10(8) CFU of Ab396 (S+Ab group), or 50 μl of 0.9% saline and 20 μl of 0.9% saline (S+S group). Cytokines, bacterial loads in the bronchoalveolar lavage fluid (BALF), lung permeability, histopathology of the lungs, and survival rates were evaluated.
  
  
  RESULTS
  Only the A+Ab mice developed extensive Ab396 pneumonia and had significantly elevated bacterial loads, increased lung leakage, and lower levels of tumor necrosis factor alpha (TNF-α) compared with the other three groups (p<0.05, Mann-Whitney U-test). Moreover, a strong synergistic effect (p<0.05, two-way analysis of variance) was observed between the acid induction and Ab396 infection, resulting in lung injury and an unfavorable survival outcome.
  
  
  CONCLUSIONS
  Lung injury caused by acid aspiration provoked secondary MDRAB pneumonia; also synergistic effects between acid aspiration and Ab396 infection resulted in a detrimental outcome in the infected mice.
authors.affiliation: Department of Internal Medicine, Chi Mei Medical Center, 901, Chung-Hwa Road, Yung-Kang Dist., Tainan City, Taiwan.
authors.forename: Shyh-Ren
authors.initials: SR
authors.lastname: Chiang
authors.forename: Hung-Jen
authors.initials: HJ
authors.lastname: Tang
authors.forename: Chung-Hua
authors.initials: CH
authors.lastname: Chen
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Chen
authors.forename: Wen-Ying
authors.initials: WY
authors.lastname: Lee
authors.forename: Ping-Chin
authors.initials: PC
authors.lastname: Chang
authors.forename: Yu-Hsin
authors.initials: YH
authors.lastname: Chiu
authors.forename: Yin-Ching
authors.initials: YC
authors.lastname: Chuang
mesh_terms: D000143:Acids / Q000008:administration & dosage / Q000009:adverse effects; D000151:Acinetobacter Infections / Q000382:microbiology* / Q000401:mortality; D040981:Acinetobacter baumannii / Q000187:drug effects*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D058491:Bacterial Load; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D004195:Disease Models, Animal; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D008168:Lung / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D010539:Permeability; D011015:Pneumonia, Aspiration / Q000382:microbiology* / Q000401:mortality
chemical_list: D000143:Acids; D000900:Anti-Bacterial Agents; D016207:Cytokines