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An experimentally pathogenic Bacillus species. II. The pathogenicity of the organism for mice
Abstract:
The pathogenic effects produced in mice by intraperitoneal (i.p.) injection of a Bacillus species (OSU 372) are presented. This organism belongs to group 3 of the genus, and members of this group have not heretofore been shown to be pathogenic for mice even under experimental conditions. However, this organism is capable of producing a fatal involvement in doses which are not considered to be overwhelming. The mean lethal dose (LD50) of the organism for 20-25 g mice by the i.p. route is about 1 times 10-8 bacteria/mouse. A rapid drop in body temperature along with severe dehydration were noted in infected animals, and hematologic studies indicated that leukopenia and hemoconcentration also occurred. Although a transient septicemia developed, the bacteria could not be recovered from the tissues of fatally infected mice after a certain point in time. Results prevented indicate that the animals died of hypovolemic shock. A possible parallel with human bacillary infection is drawn.
Insights
A novel Bacillus species (OSU 372) causes fatal infections in mice, leading to hypovolemic shock. This study details the mean lethal dose and observed pathogenic effects, including temperature drop and dehydration.
Area of Science:
- Microbiology
- Pathogenesis
- Animal Models
Background:
- Bacillus species group 3 are typically non-pathogenic in mice.
- Experimental data on the pathogenicity of Bacillus OSU 372 in mice is limited.
Purpose of the Study:
- To investigate the pathogenic effects of Bacillus OSU 372 in a murine model.
- To determine the mean lethal dose (LD50) and clinical signs associated with infection.
Main Methods:
- Intraperitoneal injection of Bacillus OSU 372 into mice.
- Monitoring of clinical signs, body temperature, and hydration levels.
- Hematologic analysis and bacterial recovery from tissues.
Main Results:
- Bacillus OSU 372 demonstrated pathogenicity in mice, with an LD50 of approximately 1 x 10^8 bacteria/mouse.
- Infected mice exhibited rapid hypothermia, severe dehydration, leukopenia, and hemoconcentration.
- Transient septicemia occurred, but bacteria were cleared from tissues before death, suggesting hypovolemic shock as the cause of mortality.
Conclusions:
- Bacillus OSU 372 can cause fatal hypovolemic shock in mice, challenging the presumed non-pathogenicity of its group.
- The findings suggest a potential parallel with human bacillary infections and warrant further investigation.