Antibodies to actin in autoimmune haemolytic anaemia

BACKGROUND: In autoimmune haemolytic anaemia (AIHA) autoreactive antibodies directed against red blood cells are upregulated leading to erythrocyte cell death. M. suis infections in pigs (IAP) induce AIHA of both the warm and the cold type. Aim of this study was to identify target autoantigens of warm autoreactive IgG antibodies. For this, sera from experimentally M. suis infected pigs were screened for autoreactivity. RESULTS: In sera of 95 % of all tested animals actin-reactive antibodies were found. The reactivity was shown to be species specific, i.e. reactivity with porcine actin was significantly higher than with rabbit-actin. Sera of animals previously immunised with the adhesion protein MSG1 of M. suis showed reactivity with actin prior to infection with M. suis indicating molecular mimicry to be involved in specific autoreactive mechanism. A potentially cross reactive epitope could be detected. CONCLUSIONS: This is the first report of autoreactive anti-actin antibodies involved in pathogenesis of autoimmune haemolytic anaemia

Update on shedding and transmission routes of porcine haemotrophic mycoplasmas in naturally and experimentally infected pigs

Horizontal transmission of Mycoplasma suis via parenteral exposure during standard practices or through bites during fightings have been identified as key epidemiological routes. However, as knowledge gaps on other potential shedding and transmission routes exist, the present study combines both laboratory experiments and field surveys to gain new insights into the epidemiology of porcine haemotrophic mycoplasmas. Splenectomised pigs were orally inoculated with a M. suis field strain and investigated for clinical signs related to infectious anaemia of pigs (IAP) and the presence of M. suis in blood, urine and saliva samples by qPCR. All blood samples were negative for M. suis and animals did not show obvious clinical signs of IAP throughout the entire study period. Additionally, urine, nasal and saliva samples from sows of conventional piglet producing farms and semen samples from a boar stud revealed no detection of M. suis and ‘Candidatus Mycoplasma haemosuis’ by qPCR. Thus, the results indicate that blood-independent transmission routes might be of minor relevance under field conditions

Inorganic pyrophosphatase in uncultivable hemotrophic mycoplasmas: identification and properties of the enzyme from Mycoplasma suis

BACKGROUND: Mycoplasma suis belongs to a group of highly specialized hemotrophic bacteria that attach to the surface of host erythrocytes. Hemotrophic mycoplasmas are uncultivable and the genomes are not sequenced so far. Therefore, there is a need for the clarification of essential metabolic pathways which could be crucial barriers for the establishment of an in vitro cultivation system for these veterinary significant bacteria.Inorganic pyrophosphatases (PPase) are important enzymes that catalyze the hydrolysis of inorganic pyrophosphate PPi to inorganic phosphate Pi. PPases are essential and ubiquitous metal-dependent enzymes providing a thermodynamic pull for many biosynthetic reactions. Here, we describe the identification, recombinant production and characterization of the soluble (s)PPase of Mycoplasma suis. RESULTS: Screening of genomic M. suis libraries was used to identify a gene encoding the M. suis inorganic pyrophosphatase (sPPase). The M. suis sPPase consists of 164 amino acids with a molecular mass of 20 kDa. The highest identity of 63.7% was found to the M. penetrans sPPase. The typical 13 active site residues as well as the cation binding signature could be also identified in the M. suis sPPase. The activity of the M. suis enzyme was strongly dependent on Mg2+ and significantly lower in the presence of Mn2+ and Zn2+. Addition of Ca2+ and EDTA inhibited the M. suis sPPase activity. These characteristics confirmed the affiliation of the M. suis PPase to family I soluble PPases. The highest activity was determined at pH 9.0. In M. suis the sPPase builds tetramers of 80 kDa which were detected by convalescent sera from experimentally M. suis infected pigs. CONCLUSION: The identification and characterization of the sPPase of M. suis is an additional step towards the clarification of the metabolism of hemotrophic mycoplasmas and, thus, important for the establishment of an in vitro cultivation system. As an antigenic and conserved protein the M. suis sPPase could in future be further analyzed as a diagnostic antigen

Detection of Mycoplasma suis in pre-suckling piglets indicates a vertical transmission

Background Transmission of Mycoplasma (M.) suis mainly occurs via iatrogenic or zootechnical manipulations or due to ranking fights. Other transmission routes including ingestion of secretes/excretes; blood-sucking arthropods and intra-uterine transmission have thought to play an epidemiological role without being experimentally proven. To investigate a vertical transmission of M. suis under field conditions blood samples from pre-suckling piglets and their corresponding dam were examined for M. suis by quantitative polymerase chain reaction (qPCR) in 21 farms in Southern Germany. Results A total of 14.35% of the 474 blood samples from pre-suckling piglets reacted qPCR positive. Additionally, M. suis was detected in 65 (31.25%) of the 208 sows at farrowing. On farm level, 16 (76.2%) of the 21 farms had at least one M. suis positive animal. M. suis positive farms had an average of 0.41 more stillborn piglets per litter than M. suis negative farms (p = 0.007). Conclusion The present study provides further insights into M. suis infection dynamics as it is the first detection of M. suis in piglets immediately after birth prior to colostrum intake and the first large scale investigation of M. suis in sows at farrowing

Persistence in Livestock Mycoplasmas—a Key Role in Infection and Pathogenesis

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Purpose of Review</jats:title> <jats:p><jats:italic>Mycoplasma</jats:italic>, economically important pathogens in livestock, often establishes immunologically complex persistent infections that drive their pathogenesis and complicate prophylaxis and therapy of the caused diseases. In this review, we summarize some of the recent findings concerning cellular and molecular persistence mechanisms related to the pathogenesis of mycoplasma infections in livestock.</jats:p> </jats:sec><jats:sec> <jats:title>Recent Findings</jats:title> <jats:p>Data from recent studies prove several mechanisms including intracellular lifestyle, immune dysregulation, and autoimmunity as well as microcolony and biofilm formation and apoptosis of different host cell types as important persistence mechanisms in several clinically significant <jats:italic>Mycoplasma</jats:italic> species, i.e., <jats:italic>M. bovis</jats:italic>, <jats:italic>M</jats:italic>. <jats:italic>gallisepticum</jats:italic>, <jats:italic>M. hyopneumoniae</jats:italic>, and <jats:italic>M</jats:italic>. <jats:italic>suis</jats:italic>.</jats:p> </jats:sec><jats:sec> <jats:title>Summary</jats:title> <jats:p>Evasion of the immune system and the establishment of persistent infections are key features in the pathogenesis of livestock mycoplasmas. In-depth knowledge of the underlying mechanisms will provide the basis for the development of therapy and prophylaxis strategies against mycoplasma infections.</jats:p> </jats:sec&gt

Survival of <i>Salmonella</i> Typhimurium, <i>Listeria monocytogenes</i>, and ESBL Carrying <i>Escherichia coli</i> in Stored Anaerobic Biogas Digestates in Relation to Different Biogas Input Materials and Storage Temperatures

Anaerobic digestates derived from agricultural mesophilic biogas plants are mainly used as organic fertilizers. However, animal derived pathogens could persist in the anaerobic digestates (ADs) posing an epidemiological risk. The present study investigated whether storage of ADs could reduce Salmonella Typhimurium, Listeria monocytogenes, and ESBL carrying Escherichia coli and whether reduction rates are dependent on temperature and substrate. Quantified bacterial suspensions were used to inoculate ADs derived from five biogas plants using different input materials to investigate the substrate dependence of the pathogen reduction. ADs were stored over six months with four different temperature profiles each representing six consecutive months, and, thus, the four seasons. Pathogen reduction during storage was shown to be strongly dependent on the temperature but also on the type of AD. This influence was higher at low temperatures. At higher temperatures (spring and summer profiles), a 5-log reduction was achieved after twelve weeks for S. Typhimurium, after twenty weeks for E. coli (ESBL) and after twenty-four weeks for L. monocytogenes in all ADs, respectively. In contrast at lower temperatures (autumn and winter profiles), a 5-log reduction was reached after twenty-four weeks for S. Typhimurium and not reached for ESBL-E. coli and L. monocytogenes. In conclusion, storing the ADs after the biogas process improves the hygienic quality and reduce the risk of introducing pathogens to the environment, but each case should be evaluated individually considering the composition of the ADs and the storage temperatures

Haemotrophic mycoplasma infection in horses

Haemotrophic mycoplasmas (HM) are parasites on the surface of red blood cells and known to infect a wide range of animals. However, there are no previous evidences of HM infections in horses. In this study HM were detected for the first time in the blood of two horses suffering from poor performance, apathy, weight loss, and anaemia. Using a HM specific PCR assay and subsequent sequencing the infective agents isolated from the blood of said horses were confirmed as closely related to the HM species Mycoplasma haemofelis and 'Candidatus Mycoplasma haemobos'

Occurrence of <i>Mycoplasma parvum</i> in German Pigs of Different Age Groups Using a Novel Quantitative Real-Time PCR Assay

Mycoplasma (M.) parvum is a hemotrophic bacterium circulating in the blood of pigs but is not considered a primary pathogen. Only a handful of studies dealing with this agent have been published since its first description in 1951, and many issues, including epidemiology and the impact of subclinical infections, are yet to be elucidated. This study aimed to establish a M. parvum specific real-time PCR for its detection and quantification in porcine blood and the application of this assay to obtain insights into the occurrence of M. parvum in German pigs. Furthermore, 16S rDNA amplicons of M. parvum positive blood samples were phylogenetically analyzed using MEGA 11 software. The established qPCR targeting the M. parvum glyceraldehyde-3-phosphate dehydrogenase encoding gene (gap) showed a lower detection limit of 10 gene copies per reaction and no cross-reactivity within the specificity test. A total of 36.0% (n = 72) of the sampled fattening pigs, 25.0% (n = 15) of the sows, and 4.37% (n = 8) of the boars tested M. parvum positive. The dendrogram showed the typical allocation of the M. parvum isolates into the “haemominutum group” subgroup within the hemotrophic Mycoplasma species. Both the novel established qPCR and the obtained epidemiological data can serve as an important basis for future studies dealing with M. parvum.</i

Genetic comparison of Brucella spp. and Ochrobactrum spp. erroneously included into the genus Brucella confirms separate genera

The facultative intracellular pathogen Brucella and the free-living bacteria Ochrobactrum are both α-proteobacteria and very close to each other. A group of researchers recently clustered Ochrobactrum strains into the genus Brucella according to a BLAST distance approach. Thus, we performed a deeper comparative genetic analysis for eleven Ochrobactrum strains and twelve different Brucella isolates to demonstrate important differences between these bacteria. In addition to the clear differences between Brucella and Ochrobactrum, like the differences in genes contents, and different genome sizes, the Brucella-specific gene bscp31 was not found in Ochrobactrum, as well as other important Brucella-specific proteins and virulence factors. Differences in antimicrobial resistance genes content and the presence or absence of plasmids were obvious between Brucella and Ochrobactrum spp. Genome alignment of Brucella spp. and Ochrobactrum spp. revealed a genome similarity of 85.7% maximum, whereas all analyzed Brucella spp. in this study had a similarity of 97.6-99.9%, and all compared Ochrobactrum spp. 82.6-98.0%. Because of these facts mentioned in this work, Brucella and Ochrobactrum should be considered separate genera