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Difference in susceptibility to gram-negative urinary tract infection between C3H/HeJ and C3H/HeN mice
Abstract:
The difference in susceptibility to urinary tract infection between C3H/HeJ and C3H/HeN mice was tested for with gram-negative strains differing in lipopolysaccharide composition. Recently, impaired clearance of Escherichia coli from the kidney of C3H/HeJ compared to C3H/HeN mice was shown to be correlated with the LPS low responsiveness. In this study, a difference in clearance from the kidneys of C3H/HeJ and C3H/HeN mice was found only with lipopolysaccharide-containing bacteria. Gram-positive bacteria, e.g., Staphylococcus saprophyticus and Streptococcus agalactiae, were recovered in essentially equal numbers from the kidneys of mice of both strains. In contrast, of the lipopolysaccharide-containing strains used, all persisted in higher numbers in the kidneys of C3H/HeJ mice than in the kidneys of C3H/HeN mice. Variations in the O side chain did not eliminate this difference. E. coli Hu734 O75+K5+ and the rfb- mutant O75-K5+ remained in similar numbers in C3H/HeJ mice, although O75-K5+ was eliminated more rapidly in C3H/HeN mice. The core structure did not affect the differential persistence in the two mouse strains. The rfb mutants with R1-R4 cores were eliminated after 24 h from the C3H/HeN mice, but remained in significant numbers in the kidneys of C3H/HeJ mice. Even the Re mutant of Salmonella minnesota persisted in low numbers in C3H/HeJ mice. The relative bacterial recovery from either mouse strain was related to the overall virulence of the infecting bacterial strain, but the difference between C3H/HeJ and C3H/HeN mice was associated with responsiveness to parts of lipopolysaccharide common to the bacterial strains tested.
Insights
Mice with low lipopolysaccharide (LPS) responsiveness show impaired clearance of LPS-containing bacteria from kidneys. This difference in urinary tract infection susceptibility between mouse strains is linked to LPS structure, not bacterial virulence.
Area of Science:
- Immunology
- Microbiology
- Infectious Diseases
Background:
- Susceptibility to urinary tract infections (UTIs) can differ between mouse strains.
- Impaired clearance of Escherichia coli in C3H/HeJ mice compared to C3H/HeN mice is linked to low lipopolysaccharide (LPS) responsiveness.
Purpose of the Study:
- To investigate the role of lipopolysaccharide (LPS) composition in differential bacterial clearance between C3H/HeJ and C3H/HeN mice.
- To determine if LPS structure influences UTI susceptibility in these mouse strains.
Main Methods:
- Infection of C3H/HeJ and C3H/HeN mice with various gram-negative bacterial strains differing in LPS.
- Assessment of bacterial recovery from kidneys at different time points post-infection.
- Analysis of LPS structure variations, including O side chain and core components, and their effect on bacterial persistence.
Main Results:
- Gram-positive bacteria were cleared equally from both mouse strains.
- LPS-containing gram-negative bacteria persisted in higher numbers in C3H/HeJ mice compared to C3H/HeN mice.
- Differential persistence was observed even with variations in LPS core structure, indicating a role for common LPS components.
Conclusions:
- The difference in UTI susceptibility between C3H/HeJ and C3H/HeN mice is primarily associated with their responsiveness to lipopolysaccharide.
- LPS structure, particularly components common to various bacterial strains, significantly impacts bacterial clearance and persistence in the kidneys.