Phylogenetic analysis of "Candidatus Mycoplasma turicensis" isolates from pet cats in the United Kingdom, Australia, and South Africa, with analysis of risk factors for infection

Abstract

Two hemotropic mycoplasmas have been recognized in cats, Mycoplasma haemofelis and "Candidatus Mycoplasma haemominutum." We recently described a third feline hemoplasma species, designated "Candidatus Mycoplasma turicensis," in a Swiss cat with hemolytic anemia. This isolate induced anemia after experimental transmission to two specific-pathogen-free cats and analysis of the 16S rRNA gene revealed its close relationship to rodent hemotropic mycoplasmas. The agent was recently shown to be prevalent in Swiss pet cats. We sought to investigate the presence and clinical importance of "Candidatus Mycoplasma turicensis" infection in pet cats outside of Switzerland and to perform the molecular characterization of isolates from different countries. A "Candidatus Mycoplasma turicensis"-specific real-time PCR assay was applied to blood samples from 426 United Kingdom (UK), 147 Australian, and 69 South African pet cats. The 16S rRNA genes of isolates from different countries were sequenced and signalment and laboratory data for the cats were evaluated for associations with "Candidatus Mycoplasma turicensis" infection. Infections were detected in samples from UK, Australian, and South African pet cats. Infection was associated with the male gender, and "Candidatus Mycoplasma haemominutum" and M. haemofelis coinfection. Coinfected cats exhibited significantly lower packed cell volume (PCV) values than uninfected cats. Phylogenetic analyses revealed that some Australian and South African "Candidatus Mycoplasma turicensis" isolates branched away from the remaining isolates. In summary, "Candidatus Mycoplasma turicensis" infection in pet cats exists over a wide geographical area and significantly decreased PCV values are observed in cats coinfected with other feline hemoplasmas.

FIG. 1.

Phylogenetic analysis of nearly complete 16S rRNA gene sequences from “Candidatus Mycoplasma turicensis” isolates from different countries and related organisms. Bootstrap values are given at the nodes of the tree; only values of ≥700 are shown. “Candidatus Mycoplasma haemominutum” (United Kingdom, AY150980; South Africa, AY150979; United States, U88564), “Candidatus Mycoplasma kahanei” (AF338269), Mycoplasma suis (U88565), “Candidatus Mycoplasma haemolamae” (AF306346), Mycoplasma wenyonii (AF016546), Mycoplasma ovis (AF338268), Mycoplasma pneumoniae (M29061), Mycoplasma haemofelis (Australia, AY150976; South Africa, AF548631; United Kingdom, AY150985), Mycoplasma haemocanis (Germany, AY150973; United States, AF197337), Mycoplasma coccoides (AY171918), Mycoplasma haemomuris (U82963), and “Candidatus Mycoplasma turicensis” isolates (D7, DQ464424; B3, DQ464423; D9, DQ464425; G5, DQ464422; 108N, DQ464421; D1, DQ464417; C12, DQ464419; Switzerland 1, DQ157150; A11, DQ464418; Switzerland 2, DQ157151; and 57A, DQ464420) are shown.

FIG. 2.

PCV values of cats grouped by hemoplasma infection status. Boxes represent the 25th, 50th (median), and 75th quartiles, with whiskers extending to the greatest and smallest values. all neg., cats not infected with any feline hemoplasma (n = 468); CMt, cats PCR positive for “Candidatus Mycoplasma turicensis” alone (n = 13); CMhm, cats PCR positive for “Candidatus Mycoplasma haemominutum” alone (n = 103); Mhf, cats PCR positive for M. haemofelis alone (n = 13); CMt-CMhm, cats coinfected with “Candidatus Mycoplasma turicensis” and “Candidatus Mycoplasma haemominutum” (n = 23); CMt-Mhf, cats coinfected with “Candidatus Mycoplasma turicensis” and M. haemofelis (n = 4). Significant differences in PCV values between groups are indicated (one-way ANOVA, P < 0.0001; Tukey's multiple comparison test, P < 0.05 [*]).