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Updated: Aug 9, 2026
Establishment and Characterization of UTI and CAUTI in a Mouse Model
Published on: June 23, 2015
Urinary-tract infection by Mycoplasma pulmonis in mice and its wider implications
Abstract:
Young adult mice were inoculated intravenously with strains JB or Peter C of Mycoplasma pulmonis. A few were inoculated intranasally with strain JB. This strain but not Peter C was isolated for 50 days or more from the urines of more than half of the mice. Those of strains TO, C3H and CBA, but not CFLP, were susceptible. Recovery of mycoplasmas was intermittent and sometimes the numbers isolated varied within individual mice and between mice of a particular strain, ranging from 5 X 10(1) to greater than or equal to 5 X 10(7) colour-changing units/ml. Fifty serial passes of M. pulmonis, strain JB, in mycoplasmal medium resulted in attenuation, the organisms after inoculation of TO mice not being recovered from the urine and excretion not being stimulated by treating the mice with progesterone. At autopsy, the organisms of early passage were usually but not invariably isolated from the kidneys of mice that had been urinary excretors. About half of the latter had no renal histopathological changes. The others had usually minimal renal perivascular lymphocytic infiltrates but occasionally more widespread inflammatory changes. The findings may have relevance to the spread of mycoplasmal infection within mouse colonies and suggest that an association between such infection and nephritis in other species, including man, should be sought more closely.
Insights
Mycoplasma pulmonis can infect mouse urine for extended periods, with varying recovery rates and kidney inflammation. Strain attenuation reduced urinary shedding and kidney pathology in susceptible mouse strains.
Area of Science:
- Microbiology
- Immunology
- Veterinary Medicine
Background:
- Mycoplasma pulmonis is a common respiratory pathogen in laboratory mice.
- Understanding its transmission and pathogenesis is crucial for maintaining healthy mouse colonies.
- Urinary tract infections by Mycoplasma pulmonis can occur and may have implications for inter-species transmission.
Purpose of the Study:
- To investigate the urinary shedding and renal tropism of Mycoplasma pulmonis in susceptible mouse strains.
- To evaluate the effect of serial passage on the virulence of Mycoplasma pulmonis.
- To explore potential associations between Mycoplasma pulmonis infection and renal pathology.
Main Methods:
- Intravenous and intranasal inoculation of young adult mice with different strains of Mycoplasma pulmonis.
- Monitoring of urinary shedding and isolation of mycoplasmas from urine and kidneys.
- Histopathological examination of renal tissues.
- Serial passage of Mycoplasma pulmonis in vitro to assess attenuation.
Main Results:
- Mycoplasma pulmonis strain JB was recovered from urine for over 50 days in susceptible mouse strains (TO, C3H, CBA), but not in CFLP mice.
- Recovery was intermittent, with variable bacterial loads.
- Organisms were isolated from kidneys of urinary excretors, often with minimal to moderate renal inflammation.
- Fifty serial passages in vitro attenuated Mycoplasma pulmonis, reducing urinary shedding and kidney pathology.
Conclusions:
- Mycoplasma pulmonis can establish persistent urinary tract infections in susceptible mice.
- Renal involvement and inflammation can occur, though not invariably.
- Attenuation through serial passage reduces virulence.
- Findings suggest potential relevance for Mycoplasma pulmonis spread in colonies and warrant further investigation into links with nephritis in other species.
