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Evidence for separate genetic defects in C3H/HeJ and C3HeB/FeJ mice, that affect susceptibility to gram-negative
Abstract:
Past studies have suggested a linkage between susceptibility to Salmonella typhimurium infection and the Lpsd genotype in C3H mice. Recently, this linkage was questioned by the finding that C3HeB/FeJ mice (Lpsn,Lpsn) were highly susceptible to systemic S. typhimurium infection. The present study shows a marked difference between C3H/HeJ and C3HeB/FeJ in their susceptibility to Gram-negative urinary tract infection. The number of E. coli and S. typhimurium recovered from the kidneys 24 hr after infection was 70 to 100 times higher in C3H/HeJ than in C3HeB/FeJ or C3H/HeN mice. Subsequently, in C3HeB/FeJ mice S. typhimurium multiplied to the level of C3H/HeJ mice, resulting in a shorter mean survival time of C3H/HeJ and C3HeB/FeJ compared with C3H/HeN mice. In contrast, E. coli remained localized to the urinary tract of C3H/HeJ mice but were eliminated from C3HeB/FeJ and C3H/HeN mice. Thus, experimental E. coli urinary tract infection appears to provide a method to differentiate the genetic defects of C3H/HeJ and C3HeB/FeJ mice. The results support an influence of the Lpsd genotype on clearance of Gram-negative bacteria from the kidneys of C3H mice.
Insights
The Lpsd genotype influences Gram-negative bacterial clearance from mouse kidneys. C3H/HeJ mice show impaired clearance of E. coli and S. typhimurium, unlike C3HeB/FeJ and C3H/HeN mice.
Area of Science:
- Immunology
- Microbiology
- Genetics
Background:
- Previous studies linked Salmonella typhimurium susceptibility to the Lpsd genotype in C3H mice.
- This association was challenged by findings of high susceptibility in C3HeB/FeJ mice (Lpsn,Lpsn) to systemic S. typhimurium infection.
Purpose of the Study:
- To investigate the differential susceptibility of C3H/HeJ and C3HeB/FeJ mice to Gram-negative urinary tract infections.
- To elucidate the role of the Lpsd genotype in bacterial clearance from the kidneys.
Main Methods:
- Experimental urinary tract infection models using Escherichia coli and Salmonella typhimurium.
- Quantification of bacterial load in kidneys 24 hours post-infection.
- Assessment of mean survival time in different mouse strains.
Main Results:
- C3H/HeJ mice exhibited significantly higher kidney bacterial loads (70-100 times) for both E. coli and S. typhimurium compared to C3HeB/FeJ and C3H/HeN mice.
- S. typhimurium multiplied in C3HeB/FeJ mice, leading to reduced survival similar to C3H/HeJ mice.
- E. coli remained localized in C3H/HeJ mice but was cleared by C3HeB/FeJ and C3H/HeN mice.
Conclusions:
- Experimental E. coli urinary tract infection effectively differentiates genetic defects between C3H/HeJ and C3HeB/FeJ mice.
- The Lpsd genotype significantly influences the clearance of Gram-negative bacteria from the kidneys in C3H mice.