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Variation in Bordetella bronchiseptica lipopolysaccharide during human infection
P Gueirard1, K Le Blay, A Le Coustumier
1Laboratoire des Bordetella, Institut Pasteur, Paris, France.
Abstract:
We previously reported the case of a human chronic Bordetella bronchiseptica respiratory infection, due to contact with infected rabbits. Lipopolysaccharides of the human isolates, of one rabbit isolate and of isolate from other origins were analyzed with sera from infected mice, rabbit and human. Antigenicity and length of the lipopolysaccharide molecules varied between isolates. We showed a progressive loss of O-chain during infection, associated with an enhanced susceptibility of the isolates to the bactericidal effect of normal serum. This observation suggests the existence of an intracellular niche which selects for strains with distinct lipopolysaccharide types.
Insights
Chronic Bordetella bronchiseptica respiratory infections in humans can involve lipopolysaccharide (LPS) changes. During infection, LPS O-chain loss increases bacterial susceptibility to serum, suggesting an intracellular niche selects for specific LPS types.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Bordetella bronchiseptica can cause chronic respiratory infections in humans, potentially acquired from animals like rabbits.
- Lipopolysaccharides (LPS) are key surface molecules of Gram-negative bacteria, influencing host-pathogen interactions and immune responses.
- Previous work identified a human chronic B. bronchiseptica infection linked to rabbit contact.
Purpose of the Study:
- To analyze the lipopolysaccharide (LPS) characteristics of human and animal Bordetella bronchiseptica isolates.
- To investigate the changes in LPS during chronic infection and their impact on bacterial serum susceptibility.
- To explore the potential role of an intracellular niche in selecting for specific LPS types.
Main Methods:
- Lipopolysaccharide (LPS) analysis of human, rabbit, and other B. bronchiseptica isolates using sera from infected mice, rabbits, and humans.
- Assessment of LPS antigenicity and molecular length.
- Evaluation of bacterial susceptibility to the bactericidal effects of normal serum.
Main Results:
- Lipopolysaccharide (LPS) antigenicity and length varied significantly among different B. bronchiseptica isolates.
- A progressive loss of the O-chain component of LPS was observed during chronic infection.
- Isolates with reduced O-chain exhibited increased susceptibility to the bactericidal activity of normal serum.
Conclusions:
- Lipopolysaccharide (LPS) heterogeneity exists in Bordetella bronchiseptica isolates from various sources.
- The loss of LPS O-chain during chronic infection is associated with altered serum resistance.
- These findings suggest that an intracellular bacterial niche may select for B. bronchiseptica strains with specific LPS structures, potentially impacting virulence and immune evasion.