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Keywords:

  • Pulmonary exposure;
  • Biotechnology agents;
  • Pseudomonas aeruginosa;
  • Pseudomonas cepacia;
  • Intestinal microbiota

Abstract

Microbial biotechnology applications have prompted research into their potential impacts on human health and the environment. In this study, a mouse model was used to evaluate indirect effects (e.g., alteration of the intestinal microbiota) of pulmonary exposure to representative biotechnology agents (Pseudomonas aeruginosa strain AC869 and Pseudomonas cepacia strain AC 1100) selected for their ability to degrade hazardous chemicals. CD-I® mice were challenged intranasally with approximately 103 or 107 colony-forming units (cfu) of strain AC869 or 108 cfu of strain AC1100. At time intervals, clearance of the microorganisms and effects on resident microbiota were determined. When the low (103 cfu) dose was administered, strain AC869 was not recovered from the small intestine but was detectable in the cecum and lungs 3 h after treatment and persisted in the nasal cavity intermittently for 14 d. Treatment of animals with 107 cfu of strain AC869 resulted in detection 14 d following treatment. Strain AC869 challenge modified the small intestinal anaerobe count and cecal obligately anaerobic gram-negative rods (OAGNR) and lactobacilli. Following exposure, Pseudomonas cepacia strain AC1100 persisted in the lungs for 7 d and was recovered from the small intestine, cecum, and nasal cavity 2 d following treatment. Strain AC1100 treatment impacted the small intestinal anaerobe count, OAGNR counts, and reduced lactobacilli numbers. Strain AC1100 also altered the cecal OAGNR and lactobacilli. Therefore, pulmonary treatment of mice with Pseudomonas aeruginosa or cepacia affects the balance of the protective intestinal microbiota, which may cause further negative health effects (e.g., harbored pathogen multiplication, opportunistic pathogen invasion, bacterial translocation).