'Candidatus mycoplasma haemodidelphidis' sp. nov., 'Candidatus mycoplasma haemolamae' sp. nov. and Mycoplasma haemocanis comb. nov., haemotrophic parasites from a naturally infected opossum (Didelphis virginiana), alpaca (Lama pacos) and dog (Canis familiaris): phylogenetic and secondary structural relatedness of their 16S rRNA genes to other mycoplasmas

'Candidatus Mycoplasma Haemoalbiventris' and Tick-Borne Pathogens in Black-Eared Opossum (Didelphis aurita) from Southeastern Brazil

The black-eared opossum (Didelphis aurita) is a South American synanthropic marsupial. The presence of opossums in domestic spaces is relevant in the One-Health context since they are hosts of pathogens and ectoparasites that may affect the health of domestic animals and humans. In this study, we aim to determine the occurrence of hemoplasmas and selected tick-borne pathogens in free-ranging black-eared opossums, along with their molecular characterization, hematological and biochemical evaluation and factors associated with infection, in the municipality of Viçosa, State of Minas Gerais, southeastern Brazil. Thirty black-eared opossums were trapped between March 2021 and June 2022. Ectoparasites were collected. Hematological and biochemical analyses were performed. DNA from EDTA-blood samples were analyzed by PCR and qPCR assays. By molecular analyses, 'Candidatus Mycoplasma haemoalbiventris' was the most prevalent hemoparasite (73.3%), followed by Hepatozoon sp. (22.2%). Significant differences were observed in the number of platelets, and in the concentration of protein and globulins in the animals infected by 'Ca. M. haemoalbiventris' when compared with the negative group. This is the first report of 'Ca. M. haemoalbiventris' infection in D. aurita.

Lists of names of prokaryotic Candidatus taxa

We here present annotated lists of names of Candidatus taxa of prokaryotes with ranks between subspecies and class, proposed between the mid-1990s, when the provisional status of Candidatus taxa was first established, and the end of 2018. Where necessary, corrected names are proposed that comply with the current provisions of the International Code of Nomenclature of Prokaryotes and its Orthography appendix. These lists, as well as updated lists of newly published names of Candidatus taxa with additions and corrections to the current lists to be published periodically in the International Journal of Systematic and Evolutionary Microbiology, may serve as the basis for the valid publication of the Candidatus names if and when the current proposals to expand the type material for naming of prokaryotes to also include gene sequences of yet-uncultivated taxa is accepted by the International Committee on Systematics of Prokaryotes.

The influence of parasitism by Trypanosoma cruzi in the hematological parameters of the white ear opossum (Didelphis albiventris) from Campo Grande, Mato Grosso do Sul, Brazil

Considered ecologically generalist, Didelphis albiventris is reported as reservoir for different species of parasites, especially Trypanosoma cruzi. However, the knowledge about the influence of T. cruzi on hematological parameters of free-living opossum remains scarce. The present study aimed to evaluate the influence of T. cruzi on hematological parameters of white-ear opossums (D. albiventris) from Campo Grande, Mato Grosso do Sul, Brazil. The blood samples and biometric data were collected from 40 opossums captured by Tomahawk and Sherman traps in six urban forest fragments located in the city. The health of these animals was inferred, mainly, by means of blood parameters (PCV, RBC, WBC, MCV and WBC differential). Molecular detection of T. cruzi infection was performed by nested polymerase chain reaction (nPCR), using 18S and 24Sα rDNA region as target. Paired-t-test and simple linear regression were used for statistical analysis. No significant difference was observed between the averages of hematological variables in relation to gender and body condition. The molecular diagnosis showed that 32.5% (13/40) of the opossums were infected by T. cruzi, which presented lymphocytosis (3.4 ± 1.5) and eosinophilia (0.09 ± 0.13). Path analysis showed that T. cruzi infection resulted in increased numbers of lymphocytes and indirectly decreased the body condition of opossums. Moreover T. cruzi infection resulted in a direct effect on decrease of MCV. Overall, our results suggest that T. cruzi infection may represent a risk to health of opossums since the lymphocytosis may cause a secondary damage on body condition of infected animals.

Prevalence and molecular characterization of canine and feline hemotropic mycoplasmas (hemoplasmas) in northern Italy

BACKGROUND

Hemotropic mycoplasmas (hemoplasmas), the agents of infectious anemia, have been reported in dogs and cats. Little data are available on hemoplasma infections in Italy. The aim of this study was to evaluate the species of hemoplasmas and their prevalence in dogs and cats of northern Italy.

METHODS

Blood samples were obtained from 117 candidate blood donor dogs, 278 free-roaming dogs and 227 free-roaming cats in 2014 and 2015. Samples were first screened for hemoplasmas with a SYBR green real time PCR. The positive samples were confirmed by a second SYBR green real time PCR and sequencing. Co-infections were detected using species-specific SYBR green real time PCR.

RESULTS

The overall prevalence in dogs was 4.5% (18/395). Among the donors only one dog was positive for Mycoplasma haemocanis (0.8%). The overall prevalence of infection in free-roaming dogs was 6.1% (17/278), which was significantly higher than in candidate donors (P < 0.05). Both M. haemocanis (13/278; 4.7%) and "Candidatus M. haematoparvum" (4/278; 1.4%) were identified. In dogs, no significant association was found between hemoplasma infection and gender, age or origin. The overall prevalence in cats was 13.2% (30/227). All three feline hemoplasma species were detected, i.e. "Candidatus Mycoplasma haemominutum" (28; 12.3%), "Candidatus Mycoplasma turicensis" (11; 4.8%) and Mycoplasma haemofelis (9; 4.0%). Half of the infected cats were co-infected (15; 6.6%) with different species of hemoplasmas. Risk factor analysis confirmed that older age, male gender and FIV positivity are predisposing factors for hemoplasma infection in cats.

CONCLUSION

This study found that candidate blood donor dogs in northern Italy show a negligible risk for hemoplasma infection, confirming the appropriateness of the candidate selection criteria and the low prevalence in the study area. Accordingly, testing for hemoplasma should be considered optional for canine blood donor screening. Hemoplasma infection was instead common in free-roaming cats, and is expected to be non-negligible in owned cats with outdoor access. Feline candidates for blood donation will therefore need to be carefully selected.

Non-ribosomal phylogenetic exploration of Mollicute species: new insights into haemoplasma taxonomy

•

The first gapA and dnaK phylogenetic analysis of Mollicute species.

•

Analysis includes a wide range of haemoplasmas species.

•

Analysis supports that haemoplasmas reside within a single clade.

•

Evidence of phylogenetic distance between the haemoplasmas and Mycoplasma species.

Nine species of uncultivable haemoplasmas and several Mycoplasma species were examined by partial sequencing of two protein-encoding housekeeping genes. Partial glyceraldehyde-3-phosphate dehydrogenase (gapA) and heat shock protein 70 (dnaK) gene sequences were determined for these Mollicute species; in total nine gapA sequences and ten dnaK sequences were obtained. Phylogenetic analyses of these sequences, along with those of a broad selection of Mollicute species downloaded from GenBank, for the individual genes, and for the gapA and dnaK concatenated data set, revealed a clear separation of the haemoplasmas from other species within the Mycoplasma genus; indeed the haemoplasmas resided within a single clade which was phylogenetically detached from the pneumoniae group of Mycoplasmas. This is the first report to examine the use of gapA and dnaK, as well as a concatenated data set, for phylogenetic analysis of the haemoplasmas and other Mollicute species. These results demonstrate a distinct phylogenetic separation between the haemoplasmas and Mycoplasmas that corresponds with the biological differences observed in these species, indicating that further evaluation of the haemoplasmas’ relationship with the Mycoplasma genus is required to determine whether reclassification of the haemoplasmas is necessary.

Genome sequence of "Candidatus Mycoplasma haemolamae" strain purdue, a red blood cell pathogen of alpacas (Vicugna pacos) and llamas (Lama glama)

We report the complete genome sequence of "Candidatus Mycoplasma haemolamae," an endemic red-cell pathogen of camelids. The single, circular chromosome has 756,845 bp, a 39.3% G+C content, and 925 coding sequences (CDSs). A great proportion (49.1%) of these CDSs are organized into paralogous gene families, which can now be further explored with regard to antigenic variation.

Mycoplasma haemocanis--the canine hemoplasma and its feline counterpart in the genomic era

Mycoplasma haemocanis is a hemotrophic mycoplasma (hemoplasma), blood pathogen that may cause acute disease in immunosuppressed or splenectomized dogs. The genome of the strain Illinois, isolated from blood of a naturally infected dog, has been entirely sequenced and annotated to gain a better understanding of the biology of M. haemocanis. Its single circular chromosome has 919 992 bp and a low G + C content (35%), representing a typical mycoplasmal genome. A gene-by-gene comparison against its feline counterpart, M. haemofelis, reveals a very similar composition and architecture with most of the genes having conserved synteny extending over their entire chromosomes and differing only by a small set of unique protein coding sequences. As in M. haemofelis, M. haemocanis metabolic pathways are reduced and apparently rely heavily on the nutrients afforded by its host environment. The presence of a major percentage of its genome dedicated to paralogous genes (63.7%) suggests that this bacterium might use antigenic variation as a mechanism to evade the host’s immune system as also observed in M. haemofelis genome. Phylogenomic comparisons based on average nucleotide identity (ANI) and tetranucleotide signature suggest that these two pathogens are different species of mycoplasmas, with M. haemocanis infecting dogs and M. haemofelis infecting cats.

Complete genome sequence of Mycoplasma haemocanis strain Illinois

Mycoplasma haemocanis is a blood pathogen that may cause acute disease in immunosuppressed or splenectomized dogs. The genome of the strain Illinois is a single circular chromosome with 919,992 bp and a GC content of 35%. Analyses of the M. haemocanis genome will provide insights into its biology and in vitro cultivation requirements.

Real-time quantitative polymerase chain reaction detection of haemoplasmas in healthy and unhealthy dogs from Central Macedonia, Greece

OBJECTIVES

The aims of this study were to determine the prevalence of canine haemoplasmas, Mycoplasma haemocanis and "Candidatus Mycoplasma haematoparvum" infection in Central Macedonia, Greece, and to evaluate any associations between canine haemoplasma infection and clinical presentation, selected laboratory data or the presence of ticks.

METHODS

Genomic DNA was purified from excess blood (n=151) submitted for haematological examination. Purified DNA was subjected to species-specific quantitative polymerase chain reaction assays duplexed with a canine DNA control quantitative polymerase chain reaction. Clinical records were retrospectively examined and selected clinical parameters were compared to haemoplasma infection status.

RESULTS

Nine samples were excluded due to inadequate canine DNA polymerase chain reaction results. Of the remaining 142 samples: eight (5·6%) were positive for M. haemocanis alone, six (4·2%) were positive for "Ca. M. haematoparvum" alone and one (0·7%) was dual positive. No association was found between haemoplasma status and age, sex, breed, health status, presence of anaemia, selected biochemistry parameters, presence of ectoparasites, routine ectoparasiticide treatment or the presence of selected tick-borne diseases.

Molecular survey and genetic characterization of tick-borne pathogens in dogs in metropolitan Recife (north-eastern Brazil)

To identify DNA of the main tick-borne pathogens in dogs from Recife (Brazil), polymerase chain reactions were carried out on blood samples of dogs treated at the Veterinary Hospital of the Universidade Federal Rural de Pernambuco from March 2007 to June 2008. The detection of DNA was performed using specific primers. Amplicons were analyzed through electrophoresis and sequencing. A phylogenetic tree was constructed using the UPGMA method, revealing that the sequences were closely related to those of strains from other geographic regions. Among the 205 blood samples analyzed, 48.78% was positive for Anaplasma platys; 38.04% was positive for Ehrlichia canis; 7.31% was positive for Babesia canis vogeli; and 0.49% was positive for Hepatozoon canis and Mycoplasma haemocanis. Coinfection of two or three pathogens was found in 23.9% (49/205) of the dogs. The subspecies B. canis vogeli was identified. Infection by H. canis and M. haemocanis is reported for the first time in dogs in the state of Pernambuco (Brazil). The data indicate that the main tick-borne pathogens in dogs in this region are E. canis and/or A. platys, followed by B. canis vogeli.

The detection of "Candidatus Mycoplasma haemobos" in cattle and buffalo in China

"Candidatus Mycoplasma haemobos" is a hemoplasma species found in cattle and has been recently reported in Switzerland and Japan. In this study, "Candidatus Mycoplasma haemobos" was shown to occur in cattle and buffalo in tropical China by PCR amplification and sequence analysis of the 16S rRNA gene from blood samples. Based on the 16S rDNA sequence, a specific PCR assay was developed. Occurrence of "Candidatus Mycoplasma haemobos" in cattle and buffalo in Guangxi, China, was determined by examining 25 buffalo blood samples, 12 yellow cattle blood samples and 42 dairy cow blood samples. The results showed that 32% (8/25) of buffalo, 41.7% (5/12) of yellow cattle, and 14.3% (6/42) of dairy cows were positive for "Candidatus Mycoplasma haemobos", respectively. Direct sequencing of representative PCR products confirmed that the amplified partial 16S rDNA sequence represented "Candidatus Mycoplasma haemobos". This is the first report of "Candidatus Mycoplasma haemobos" in buffalo, yellow cattle, and dairy cows in China.

Antigen specificity of the humoral immune response to Mycoplasma haemofelis infection

The aim of the present study was to characterize the antigenic specificity of the humoral immune response made by cats infected with the feline hemoplasma, Mycoplasma haemofelis. A crude M. haemofelis antigen preparation was prepared from red blood cells (RBCs) collected from a cat at the time of a high level of bacteremia. Plasma samples were collected from six cats before and after experimental infection with M. haemofelis, with regular sampling being performed from 15 to 149 or 153 days postinfection (dpi). Preinfection RBC membrane ghosts were prepared from these six cats and used to identify erythrocyte proteins that may have contaminated the M. haemofelis antigen preparation. The M. haemofelis antigen preparation comprised 11 protein bands. The immunodominant bands on Western blotting with infected cat plasma had molecular masses of 78, 68, 60, 48, and 38 kDa. Most cats (n = 5) had plasma antibody that reacted with at least one band (always including the one of 68 kDa) at 15 dpi, and all cats were seroreactive by 29 dpi. The maximum number of antibodies from an individual animal specific for an antigen was identified in plasma collected from 57 to 99 dpi. Contamination of the M. haemofelis antigen preparation with RBC membrane proteins was observed. The contaminating RBC proteins had molecular masses of from 71 to 72 kDa (consistent with band 4.2) and 261 and 238 kDa (consistent with spectrin), and these were recognized by all plasma samples. A range of M. haemofelis antigens is recognized by cats infected experimentally with the organism. These represent possible targets for immunoassays, but care must be taken to prevent false-positive results due to host protein contamination.

Development and use of real-time PCR to detect and quantify Mycoplasma haemocanis and "Candidatus Mycoplasma haematoparvum" in dogs

Two canine haemoplasma species have been recognised to date; Mycoplasma haemocanis (Mhc), which has been associated with anaemia in splenectomised or immunocompromised dogs, and "Candidatus Mycoplasma haematoparvum" (CMhp), recently described in an anaemic splenectomised dog undergoing chemotherapy. The study aim was to develop quantitative real-time PCR assays (qPCRs) incorporating an endogenous internal control to detect Mhc and CMhp and to apply these assays to DNA samples extracted from canine blood collected in Northern Tanzania (n=100) and from dogs presented to a Trinidadian veterinary hospital (n=185). QPCRs specific for Mhc and CMhp were designed using 16S rRNA gene sequence data, and each was duplexed with an assay specific for canine glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The assays detected < or =10 copies of a sequence-specific haemoplasma plasmid per reaction and neither assay showed cross-reactivity with 10(6) copies of the sequence-specific plasmid from the non-target canine haemoplasma species. Nineteen of the 100 Tanzanian samples (19%) were positive for Mhc alone and one (1%) was dually infected. One Trinidadian sample was negative for canine GAPDH DNA and was excluded from the study. Of the 184 remaining Trinidadian samples, nine (4.9%) were positive for Mhc alone, five (2.7%) for CMhp alone, and two (1.1%) dually infected. This is the first report of canine haemoplasma qPCR assays that use an internal control to confirm the presence of amplifiable sample DNA, and their application to prevalence studies. Mhc was the most commonly detected canine haemoplasma species.

MHC standing genetic variation and pathogen resistance in wild Atlantic salmon

Pathogens are increasingly emerging in human-altered environments as a serious threat to biodiversity. In this context of rapid environmental changes, improving our knowledge on the interaction between ecology and evolution is critical. The objective of this study was to evaluate the influence of an immunocompetence gene, the major histocompatibility complex (MHC) class IIbeta, on the pathogen infection levels in wild Atlantic salmon populations, Salmo salar, and identify selective agents involved in contemporary coevolution. MHC variability and bacterial infection rate were determined throughout the summer in juvenile salmon from six rivers belonging to different genetic and ecological regions in Québec, Canada. A total of 13 different pathogens were identified in kidney by DNA sequence analysis, including a predominant myxozoa, most probably recently introduced in North America. Infection rates were the highest in southern rivers at the beginning of the summer (average 47.6+/-6.3% infected fish). One MHC allele conferred a 2.9 times greater chance of being resistant to myxozoa, while another allele increased susceptibility by 3.4 times. The decrease in frequency of the susceptibility allele but not other MHC or microsatellite alleles during summer was suggestive of a mortality event from myxozoa infection. These results supported the hypothesis of pathogen-driven selection in the wild by means of frequency-dependent selection or change in selection through time and space rather than heterozygous advantage, and underline the importance of MHC standing genetic variation for facing pathogens in a changing environment.

Description of outcomes of experimental infection with feline haemoplasmas: copy numbers, haematology, Coombs' testing and blood glucose concentrations

The aim of this study was to compare blood copy, haematological and glucose values between cats experimentally infected with either Mycoplasma haemofelis (Group HF: 10 cats), 'Candidatus M. haemominutum' (Group HM: 3 cats) or 'Candidatus M. turicensis' (Group TU: 3 cats). Blood samples were collected regularly up to 85 days post-infection (DPI) for haemoplasma real-time quantitative PCR, haematology, Coombs' testing and blood glucose measurement. Statistical analysis was performed using a general linear model (ANOVA) appropriate for a repeated measures experiment with significance set as P<0.05. Cats in Group TU had significantly lower blood copy numbers than cats in Group HF (P<0.001) and HM (P<0.001). All Group HF cats developed anaemia (often severe), macrocytosis and evidence of erythrocyte-bound antibodies whereas Groups HM and TU cats did not. Group HF had significantly lower PCVs, haemoglobin concentrations and red blood cell counts, and significantly higher mean cell volumes, than Groups HM and TU. In Group HF, erythrocyte-bound antibodies reactive at 4 degrees C (both IgM and IgG) appeared between 8 and 22 DPI and persisted for two to four weeks, whereas those reactive at 37 degrees C (primarily IgG) appeared between 22 and 29 DPI and persisted for one to five weeks. In most cats antibodies appeared after the fall in haemoglobin started. Although Group TU had significantly lower glucose concentrations than Groups HF (P=0.006) and HM (P=0.027), mean blood glucose concentrations remained within the reference range in all groups. This study demonstrates that M. haemofelis infection, in contrast to 'Candidatus M. haemominutum' and 'Candidatus M. turicensis' infection, can result in a severe macrocytic anaemia and the development of cold and warm reactive erythrocyte-bound antibodies.

RNase P RNA gene (rnpB) phylogeny of Hemoplasmas and other Mycoplasma species

Partial sequences of the RNase P RNA gene (rnpB) were obtained from a number of hemoplasmas and other Mycoplasma species. Phylogenetic analysis of these sequences showed that all hemoplasmas were present within a single clade and were most closely related to Mycoplasma fastidiosum, similar to the results found with 16S rRNA gene phylogeny.

Mycoplasma suis antigens recognized during humoral immune response in experimentally infected pigs

Today, serodiagnostic tests for Mycoplasma suis infections in pigs have low accuracies. The development of novel serodiagnostic strategies requires a detailed analysis of the humoral immune response elicited by M. suis and, in particular, the identification of antigenic proteins of the agent. For this study, indirect enzyme-linked immunosorbent assay (ELISA) and immunoblot analyses were performed using pre- and sequential postinoculation sera from M. suis-infected and mock-infected control pigs. M. suis purified from porcine blood served as the antigen. Eight M. suis-specific antigens (p33, p40, p45, p57, p61, p70, p73, and p83) were identified as targets of the immunoglobulin G (IgG) antibody response during experimental infection, with p40, p45, and p70 being the preferentially recognized M. suis antigens. Besides the M. suis-specific antigens, porcine immunoglobulins were identified in blood-derived M. suis preparations. By immunoglobulin depletion, the specificity of the M. suis antigen for use in indirect ELISA was significantly improved. M. suis-specific Western blot and ELISA reactions were observed in all infected pigs by 14 days postinfection at the latest and until week 14, the end of the experiments. During acute clinical attacks of eperythrozoonosis, a derailment of the antibody response, determined by decreases in both the M. suis net ELISA values and the numbers of M. suis-specific immunoblot bands, was accompanied by peaking levels of autoreactive IgG antibodies. In conclusion, the M. suis-specific antigens found to stimulate specific IgG antibodies are potentially useful for the development of novel serodiagnostic tests.

Demonstration of two distinct hemotropic mycoplasmas in French dogs

In North America it has been shown that distinct hemotropic mycoplasmas exist in dogs. Blood samples from 460 French dogs were analyzed by PCR to evaluate hemoplasma infection status. Seventy-one dogs (15.4%) were positive; of these, 44 (9.6%) were infected with an organism closely related to "Candidatus Mycoplasma haemoparvum" only, 15 (3.3%) were infected with Mycoplasma haemocanis only, and 12 dogs (2.6%) were dually infected with both organisms.

Phylogenetic analysis of hemoplasma species: an international study

Nearly complete 16S rRNA gene sequences for feline and canine hemoplasma isolates from Europe, Australia, Africa, and Asia showed almost 100% identity to those previously reported for United States isolates. Partial sequences of the RNA subunit of the RNase P gene were also determined, and RNase P-based phylogenetic analysis showed that the hemoplasmas are most closely related to the members of the Mycoplasma pneumoniae group.