Tissue sequestration of 'Candidatus Mycoplasma turicensis'
Marilisa Novacco1, Barbara Riond, Marina L Meli
1Clinical Laboratory, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 260, 8057 Zurich, Switzerland.
Abstract:
'Candidatus Mycoplasma turicensis' ('Candidatus M. turicensis') is a hemoplasma species that infects felids. It differs from other feline hemoplasma species due to its particular infection kinetics and phylogenetic similarity to rodent hemoplasma species. The lower and shorter bacteremia produced by 'Candidatus M. turicensis' suggests a possible tissue sequestration of the organism. The aim of this study was to explore this possibility. Five specified-pathogen free cats were subcutaneously inoculated with 'Candidatus M. turicensis' and sacrificed 86 days after inoculation. Thirty-one selected organs were collected upon necropsy, and samples were analyzed by real-time Taqman(®) PCR. The humoral immune response was monitored by DnaK ELISA. All five cats had detectable 'Candidatus M. turicensis' loads in the majority (52-100%) of the tested tissues. High 'Candidatus M. turicensis' tissue loads (average 3.46×10(4) copies/10 mg) were detected in the samples. The presence of the organisms in the tissues could not be explained by the blood burdens because the blood of four out of five cats tested PCR-negative at the time of necropsy. This is the first study to describe the distribution of 'Candidatus M. turicensis' in various organs; it also demonstrates that, in contrast to other feline hemoplasma species, significant sequestration of 'Candidatus M. turicensis' occurs in many tissues. These results represent an important step toward the understanding of the pathogenesis of 'Candidatus M. turicensis'.
Insights
Candidatus Mycoplasma turicensis, a feline hemoplasma, significantly sequesters in various tissues, unlike other feline hemoplasmas. This tissue tropism explains its unique infection patterns and low bacteremia in cats.
Area of Science:
- Veterinary Microbiology
- Infectious Diseases
- Pathogenesis Studies
Background:
- 'Candidatus Mycoplasma turicensis' (Candidatus M. turicensis) is a hemoplasma species infecting felids.
- It exhibits distinct infection kinetics and phylogenetic links to rodent hemoplasmas.
- Lower bacteremia suggests potential tissue sequestration, a possibility not yet explored.
Purpose of the Study:
- To investigate the tissue distribution and sequestration of 'Candidatus M. turicensis' in experimentally infected cats.
- To determine if tissue tropism explains the organism's unique infection characteristics.
Main Methods:
- Five pathogen-free cats were subcutaneously inoculated with 'Candidatus M. turicensis'.
- Cats were necropsied 86 days post-inoculation, with 31 organs collected for analysis.
- Real-time Taqman PCR was used to quantify 'Candidatus M. turicensis' loads in tissues and blood.
- Humoral immune response was assessed using DnaK ELISA.
Main Results:
- 'Candidatus M. turicensis' was detected in the majority of tested tissues (52-100%) across all five cats.
- High bacterial loads were found in tissues (average 3.46×10^4 copies/10 mg).
- Blood samples from four out of five cats were PCR-negative at necropsy, indicating low or absent bacteremia despite tissue presence.
Conclusions:
- This study is the first to map the organ distribution of 'Candidatus M. turicensis'.
- 'Candidatus M. turicensis' exhibits significant sequestration in multiple tissues in cats.
- This tissue tropism differentiates it from other feline hemoplasmas and is key to understanding its pathogenesis.
