TABLE 6.
Experimental urinary tract infection of rats by different K. pneumoniae strains
| Strain | Infectious dose (CFU/rat) | Sample | Infectiona measured by:
|
|
|---|---|---|---|---|
| % of infected ratsb | Viable countsc | |||
| KT769 (O5:K57, wild type) | 1.2 × 109 | Kidney | 100 | 6.8 ± 0.7 |
| Bladder | 100 | 6.5 ± 0.5 | ||
| Urine | 100 | 8.6 ± 0.5 (6)a | ||
| KT769-1 (O5−; wbdC defined insertion KT769 mutant | 0.9 × 109 | Kidney | 30 | 3.8 ± 0.3 |
| Bladder | 20 | 3.6 ± 0.5 | ||
| Urine | 20 | 5.8 ± 0.4 (2) | ||
| KT769-6 (O5−; wzm wzt KT769 deletion mutant | 1.1 × 109 | Kidney | 30 | 3.9 ± 0.4 |
| Bladder | 30 | 3.2 ± 0.7 | ||
| Urine | 20 | 5.6 ± 0.2 (2) | ||
| KT769-1C (O5+, KT769-1 complemented with CosKT4) | 1.0 × 109 | Kidney | 90 | 6.9 ± 0.6 |
| Bladder | 90 | 6.3 ± 0.5 | ||
| Urine | 100 | 8.4 ± 0.8 (4) | ||
| KT769-6C (O5+, KT769-6 complemented with CosKT4) | 1.2 × 109 | Kidney | 100 | 7.0 ± 0.8 |
| Bladder | 100 | 6.5 ± 0.3 | ||
| Urine | 100 | 8.3 ± 0.6 (6) | ||
a
A total of 20 kidneys and 10 bladders were studied in each group. Numbers in parentheses represent numbers of urine samples studied.
b
Percentage of cultures that were positive. The smallest number of organisms detectable by the method was 50 CFU per g (kidney or bladder) or per ml (urine). The values for the O5− mutants correspond to the percentage of animals infected.
c
Values represent the mean log10 CFU per gram or per milliliter ± standard deviation of the positive cultures. All the assays were done at least in triplicate.