Lipopolysaccharide-responder and nonresponder C3H mouse strains are equally susceptible to an induced Escherichia coli urinary tract infection.

Host defense against bacterial urinary tract infections (UTI) includes both inflammatory and immune responses to infecting bacteria. The cellular events leading up to local inflammation are thought to be under genetic control and initiated by lipopolysaccharides (LPS) of gram-negative bacteria such as Escherichia coli. It has been previously reported that mice which lack functional Lps genes are more susceptible to induced E. coli UTI than mice with normal mitogenic responses to LPS. In contrast to these findings, data in this report demonstrate that LPS-responder and nonresponder C3H mouse strains are equally susceptible to E. coli UTI. When C3H/OuJ (Lps(n)/Lps(n)) and C3H/HeJ (Lps(d)/Lps(d)) were intravesically inoculated with equal numbers of uropathogenic E. coli organisms, neither strain was able to effectively resolve the induced UTI. The inability of C3H/OuJ mice to combat the infection was not due to an impaired response to LPS, nor could defect in the local inflammatory response be identified. The results indicate that factors other than LPS responsiveness are also important in determining hose resistance to UTI.