Mycoplasma Suis Research Articles

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

BackgroundTransmission 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.ResultsA 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).ConclusionThe 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.

First molecular detection of Mycoplasma suis in the pig louse Haematopinus suis (Phthiraptera: Anoplura) from Argentina

Porcine haemoplasmosis caused by Mycoplasma suis affects the global pig industry with significant economic losses. The main transmission route of M. suis is through the blood and some haematophagous arthropods, like flies and mosquitoes, could be the vectors to this pathogen. However, the presence of M. suis in pig haematophagous ectoparasites in natural conditions has not yet been studied. The most frequent ectoparasite in pigs is the blood-sucking louse Haematopinus suis, an obligate and permanent parasite. Therefore, this work aims to study the occurrence of M. suis in H. suis samples from both domestic and wild pig populations from Argentina; using the 16S rRNA gene. A total of 98 sucking lice, collected from domestic and wild pigs from Buenos Aires Province in central Argentina, were examined. We found M. suis DNA in 15 H. suis samples (15.30%). Positive lice were detected from all studied populations. This is the first report of M. suis presence in H. suis, being also the first detection in a pig ectoparasite species. We conclude that H. suis could serve as a mechanical vector for M. suis. This information not only extends the knowledge about the pathogen spectrum potentially transmitted by H. suis, but may be also useful in epidemiological studies about Mycoplasma.

Molecular detection of Mycoplasma suis in extensive pig production systems in the State of Maranhão, northeast Brazil.

Mycoplasma suis is a bacterium that causes hemoplasmosis in pigs. This agent is capable of adhering to the surface of porcine erythrocytes, inducing structural changes on these cells. In Brazil, there are few reports about the disease, its causal agent, and the economic impact of this pathogen on pig production systems and farm sanitation. The present study aimed to investigate the occurrence of M. suis in extensive swine farms located in the counties of Itapecuru Mirim, Santa Rita and Rosario, State of Maranhão, northeast Brazil. For such purpose, 64 blood samples of pigs from these facilities were tested for M. suis using a 16S rRNA gene-based quantitative real-time PCR (qPCR); 82.3%, 65.2% and 25% of blood samples of swine from farms in the cities of Itapecuru Mirim, Santa Rita and Rosario were positive for M. suis by qPCR, respectively. This study shows, for the first time, that M. suis circulates in pig populations from the state of Maranhão, Northeast Brazil.

High frequency and molecular characterization of porcine hemotrophic mycoplasmas in Brazil

Mycoplasma suis and Mycoplasma parvum are the two hemotrophic mycoplasmas species described in pigs. M. suis is involved in infectious anemia, while M parvum infection is commonly subclinical. The objectives of this study were twofold: (i) to investigate the prevalence of porcine hemotrophic mycoplasmas in sows from the southern region of Brazil by quantitative real-time PCR (qPCR) and (ii) to genetically characterize a subset of the samples based on the 16S rRNA gene. A total of 429 blood samples were evaluated from 53 different farm sites. Porcine hemoplasmas was detected at all the 53 tested sites and in 79.72% of the samples (342/429). Two sequences were obtained for Mycoplasma spp. The phylogenetic analysis based on the 16S rRNA gene (900 bp) showed that the Mycoplasma sequences were closely related to the M. suis cluster and that one sequence was positioned in the M. parvum cluster. In conclusion, porcine hemoplasmas have a high rate of prevalence in sows from commercial farms in the southern region of Brazil. This study demonstrated the first molecular detection and characterization of partial 16S rRNA gene of M. parvum in Brazil.

Molecular detection of Mycoplasma suis in captive white-lipped peccaries (Tayassu pecari) and wild boars (Sus scrofa) in Brazil.

Mycoplasma suis, the etiological agent of swine hemoplasmosis, is an epicellular bacterium that adheres to the surface of pig erythrocytes leading to deformations of the target cells. Little is known about the occurrence of M. suis in wild swine populations around the world, its economic impact on swine herds, and the risk of human infection. The aim of this study was to investigate, by quantitative real-time PCR (qPCR) based on the 16S rRNA gene, the occurrence of M. suis in a captive population of white-lipped peccaries (100 Tayassu pecari) and in free-living wild boars (14 Sus scrofa) in Brazil. None of the white-lipped peccaries were positive for M. suis, whereas seven (50%) wild boars were positive in qPCR assays. The quantification of M. suis-16S rRNA copies/μL ranged from 1.42 × 10° to 3.906 × 101 in positive animals, indicating a low bacteremia and a chronic carrier status in free-living wild boars. In conclusion, M. suis might be a non-frequent pathogen in wild suids maintained in captivity. Despite the low bacteremia, the prevalence of M. suis in wild boar population in Brazil seems to be high.

RNA-Seq based transcriptome of whole blood from immunocompetent pigs (Sus scrofa) experimentally infected with Mycoplasma suis strain Illinois

Pigs are popular animal models in biomedical research. RNA-Seq is becoming the predominant tool to investigate transcriptional changes of the pig’s response to infection. The high sensitivity of this tool requires a strict control of the study design beginning with the selection of healthy animals to provide accurate interpretation of research data. Pigs chronically infected with Mycoplasma suis often show no obvious clinical signs, however the infection may affect the validity of animal research. The goal of this study was to investigate whether or not this silent infection is also silent at the host transcriptional level. Therefore, immunocompetent pigs were experimentally infected with M. suis and transcriptional profiles of whole blood, generated by RNA-Seq, were analyzed and compared to non-infected animals. RNA-Seq showed 55 differentially expressed (DE) genes in the M. suis infected pigs. Down-regulation of genes related to innate immunity (tlr8, chemokines, chemokines receptors) and genes containing IFN gamma-activated sequence (gbp1, gbp2, il15, cxcl10, casp1, cd274) suggests a general suppression of the immune response in the infected animals. Sixteen (29.09%) of the DE genes were involved in two protein interaction networks: one involving chemokines, chemokine receptors and interleukin-15 and another involving the complement cascade. Genes related to vascular permeability, blood coagulation, and endothelium integrity were also DE in infected pigs. These findings suggest that M. suis subclinical infection causes significant alterations in blood mRNA levels, which could impact data interpretation of research using pigs. Screening of pigs for M. suis infection before initiating animal studies is strongly recommended.

Identification of erythrocyte membrane proteins interacting with Mycoplasma suis GAPDH and OSGEP

Mycoplasma suis (M. suis) is an uncultivable haemotrophic mycoplasma that parasitizes the red blood cells of a wide range of domestic and wild animals. Adhesion of M. suis to host erythrocytes is crucial for its unique RBC-dependent lifecycle. MSG1 protein (now named as GAPDH) with homology to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was the first identified adhesion protein of M. suis. In this study, we found that O-sialoglycoprotein endopeptidase (OSGEP) is another M. suis protein capable of binding porcine erythrocytes. Recombinant OSGEP expressed in E. coli demonstrated surface localization similar to GAPDH. Purified rOSGEP bound to erythrocyte membrane preparations in a dose-dependent manner and this adhesion could be specifically inhibited by anti-rOSGEP antibodies. E. coli transformants expressing OSGEP on their surface were able to adhere to porcine erythrocytes. Furthermore, using far-western and pull-down assays, we determined the host membrane proteins that interacted with OSGEP and GAPDH were Band3 and glycophorin A (GPA). In conclusion, our studies indicated that OSGEP and GAPDH could interact with both Band3 and GPA to mediate adhesion of M. suis to porcine erythrocytes.

Genetic characterization and phylogenetic analysis of hemotrophic mycoplasmas in camel (Camelus dromedarius)

So far, a number of hemotrophic mycoplasma (HM) species have been reported from different animals, mostly based on the 16S rDNA gene sequence analysis. Although previous studies have described Candidatus Mycoplasma haemolamae from alpaca (Lama pacos), llama (Lama glama), and vicuna (Lama vicugna) in Camelidae, data on the causative agent(s) of hemotrophic mycoplasmosis or hemoplasmosis are insufficient in dromedary camel (Camelus dromedarius). The purpose of the present molecular study was to investigate hemotrophic mycoplasmosis in Iranian dromedary camel. Accordingly, a total number of 100 EDTA-anticoagulated blood specimens were randomly collected via the jugular vein from camels. In the present study, partial sequence data of the 16S rDNA was employed as a molecular approach for genetic characterization and phylogenetic analysis of the Iranian strains of hemotrophic mycoplasma in camel. The phylogenetic analysis revealed that one species belonged to the “haemominutum group” within the cluster of hemoplasmas (the former genus Eperythrozoon), the other phylogenetic analysis found species belonging to the “haemofelis group” with the hemoplasma cluster (representing the former genus Haemobartonella). Out of the 100 tested blood samples, 2 (2.0%) were found positive by the PCR assay. The phylogenetic tree inferred from 16S rDNA sequences showed that examined camels were naturally infected with two distinct species of hemotrophic mycoplasmas. The first strain was phylogenetically placed into an undescribed hemotrophic mycoplasma group with a new species of Mycoplasma sp. isolated from a pig in China with 99% genetic similarity. However, the second strain seemed basal to a large lineage of Mycoplasma suis with a low sequence similarity of 93.5–95.9%. In summary, this is the first molecular-based study to detect the presence of two genetically different hemotrophic mycoplasma strains in dromedary camel that are phylogenetically linked to two pathogenic swine species.

Development of an immunochromatographic test based on monoclonal antibodies against surface antigen 3 (TgSAG3) for rapid detection of Toxoplasma gondii

The immunochromatographic test (ICT) is a convenient and low-cost method that can rapidly obtain results (10 min) under normal conditions. In this study, we established an ICT assay with two monoclonal antibodies: TgSAG3-3A7 and TgSAG3-4D5 based on the conserved protein of TgSAG3 that can be expressed in all the infective stages of T. gondii. 20 nm gold particles were prepared and conjugated with TgSAG3-3A7 MAb at the concentration of 12.5 μg/mL. TgSAG3-4D5 MAb were used as the capture antibody because of its higher affinity tested by ELISA. The detection limit of the ICT assay was 100 ng with visual detection under optimal conditions of analysis. Positive porcine serum of Cryptosporidium suis, Mycoplasma suis, Streptococcus suis, Salmonella choleraesuis, Cysticercus cellulosae, Isospora suis, and Trichinella spiralis were used to evaluate the specificity of this ICT and no cross-reactivity was observed. 310 porcine serum samples obtained from pig farms in Zhejiang Province, China were detected by this ICT and ELISA kit, 23 positive samples were found by the developed strip with the rate of 7.42% comparing with 22 positive samples detected by the commercially ELISA kit which the positive rate was 7.1%, the relative sensitivity and specificity of this ICT are 100% and 99.65%. Therefore, the ICT established in this study is proved effective, simple, specific and sensitive of T. gondii detection.

High occurrence of Mycoplasma suis infection in swine herds from non-technified farms in Mossoró, state of Rio Grande do Norte, Northeastern Brazil.

Mycoplasma suis, the etiological agent of swine hemoplasmosis, has been neglected in swine herds around the world. Swine hemoplasmosis is frequently associated with hemolytic anemia, disgalacty, infertility and immunosuppression, and it results in significant economic losses. This study investigates the occurrence of M. suis in non-technified swine herds in the northeastern region of Brazil using quantitative PCR (qPCR) based on the 16S rRNA gene. Between March and August 2013, blood samples from 147 swine were collected during slaughter in the city of Mossoró, state of Rio Grande do Norte, northeastern Brazil. One hundred and twelve samples (76.19%) were positive for M. suis by qPCR assays. The range of Cqs and quantification (copies of a M. suis-16S rRNA gene fragment/µL) was 20.86-37.89 and 1.64×101-6.64×107, respectively. One can conclude that M. suis infection have high occurrence (76,19%) in non-technified swine-rearing systems in Mossoró in the state of Rio Grande do Norte, Brazil.

Detection of Mycoplasma haemocanis, Mycoplasma haematoparvum, Mycoplasma suis and other vector-borne pathogens in dogs from Córdoba and Santa Fé, Argentina.

BackgroundIn Argentina, only very few reports are available for canine tick-borne diseases where most are related to parasitic diseases. The objective of this survey was to investigate the prevalence of tick-borne pathogens in 70 dogs from Santa Fé and Córdoba, Argentina.MethodsMicroscopic blood smear examination as well as polymerase chain reaction (PCR) amplification using species-specific markers of Anaplasma, Babesia, Bartonella, Borrelia, Ehrlichia, Francisella, Mycoplasma (hemotropic group) and Rickettsia, followed by DNA sequencing were used to establish the prevalence of each infecting pathogen.ResultsBlood smear analysis showed 81% (57/70) prevalence of structures morphologically compatible with hemotropic mycoplasmas. No structures resembling either piroplasms or Anaplasma/Ehrlichia were detected. Hemotropic mycoplasma species (Mycoplasma haematoparvum, Mycoplasma haemocanis and Mycoplasma suis) were the most prevalent pathogens detected with an overall prevalence of 77.1%. Anaplasma platys was detected and identified in 11 of the 70 dogs (15.7%), meanwhile two Bartonella spp. (B. clarridgeiae and an uncharacterized Bartonella sp.) and Babesia vogeli were detected at 3 and 7% prevalence, respectively.ConclusionsThe work presented here describes a high molecular prevalence for hemotropic mycoplasma species in each of the five locations selected. Three Mycoplasma spp., including Mycoplasma suis, reported for the first time in dogs have been identified by DNA amplification and sequencing. This study highlights the risk that these bacterial pathogens represent for companion animals and, due to their potential zoonotic nature, also for people.

Updating the proteome of the uncultivable hemotrophic Mycoplasma suis in experimentally infected pigs.

Mycoplasma suis belongs to the hemotrophic mycoplasmas that are associated with acute and chronic anemia in a wide range of livestock and wild animals. The inability to culture M. suis in vitro has hindered its characterization at the molecular level. Since the publication of M. suis genome sequences in 2011 only one proteome study has been published. Aim of the presented study was to significantly extend the proteome coverage of M. suis strain KI_3806 during acute infection by applying three different protein extraction methods followed by 1D SDS-PAGE and LC-MS/MS. A total of 404 of 795 M. suis KI_3806 proteins (50.8%) were identified. Data analysis revealed the expression of 83.7% of the predicted ORFs with assigned functions but also highlights the expression of 179 of 523 (34.2%) hypothetical proteins with unknown functions. Computational analyses identified expressed membrane-associated hypothetical proteins that might be involved in adhesion or host-pathogen interaction. Furthermore, analyses of the expressed proteins indicated the existence of a hexose-6-phosphate-transporter and an ECF transporter. In conclusion, our proteome study provides a further step toward the elucidation of the unique life cycle of M. suis and the establishment of an in vitro culture. All MS data have been deposited in the ProteomeXchange with identifier PXD002294 (http://proteomecentral.proteomexchange.org/dataset/PXD002294).

Occurrence and molecular characterization of Bartonella spp. and hemoplasmas in neotropical primates from Brazilian Amazon.

Little is known about the prevalence and genetic diversity of Bartonella spp. and hemoplasmas in nonhuman primates (NHP). The present study aimed to investigate the occurrence of and assess the phylogenetic position of Bartonella spp. and hemoplasma species infecting neotropical NHP from Brazilian Amazon. From 2009 to 2013, a total of 98 blood samples from NHP belonging to the Family Cebidae were collected in the island of São Luís, state of Maranhão, of which 87 NHP were from Wild Animal Screening Center (CETAS) in the municipality of São Luís, and 11 (9 Sapajus sp. and 2 Saimiri sciureus) were from NHP caught in the Sítio Aguahy Private Reserve. DNA samples were screened by previously described PCR protocols for amplifying Bartonella spp. and Mycoplasma spp. based on nuoG, gltA and 16S rRNA genes, respectively. Purified amplicons were submitted to sequencing and phylogenetic analysis. Bacteremia with one or more Bartonella spp. was not detected in NHP. Conversely, 35 NHP were PCR positive to Mycoplasma spp. The Blastn analysis of seven positive randomly selected sequencing products showed percentage of identity ranging from 95% to 99% with other primates hemoplasmas. The Maximum Likelihood phylogenetic analysis based on a 1510 bp of 16S rRNA gene showed the presence of two distinct clusters, positioned within Mycoplasma haemofelis and Mycoplasma suis groups. The phylogenetic assessment suggests the presence of a novel hemoplasma species in NHP from the Brazilian Amazon.

Enzyme-linked immunosorbent assay for the detection of antibodies against the extracellular domain of the OxaA membrane protein of Mycoplasma suis

Epidemics of swine infected with Mycoplasma suis, a hemotrophic pathogen, cause substantial economic losses to the swine industry worldwide. The complementary DNA sequences encoding two predicted extracellular domains of the OxaA protein of M. Suis were obtained using polymerase chain reaction and standard molecular cloning methods. The OxaA domains were expressed separately in Escherichia coli as glutathione-S-transferase (GST) fusion proteins, designated as GST-A and GST-B. The antigenicity of the GST-A and -B recombinant proteins was confirmed by western blotting. The GST-A and -B proteins were approximately 33.9 kDa and 34.6 kDa in size, respectively. An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of antibodies against the OxaA protein of M. Suis using the GST-B protein. The efficacy of the GST-B-based ELISA was compared to a previously described ELISA ??method based on the analysis of serum samples from 150 swine, and the M. Suis-positive rates were 22.7% and 17.3%, respectively. The GST-B-based ELISA demonstrated significantly higher levels of specificity, sensitivity, and stability for the serodiagnosis of M. Suis infection in swine than those of the previously described method.

Application of quantitative PCR for detection of Mycoplasma suis in blood samples

Abstract The aim of the study was to develop and validate a real-time PCR method, using a TaqMan probe, for quantification of Mycoplasma suis in porcine blood. No PCR signals with closely related non-haemotrophic mycoplasmas were obtained. The detection limit of PCR for plasmid combined with blood DNA was determined to be 103/reaction (5 μL of DNA) (1.2x105 target copies in 1 mL of blood). The linearity of real-time PCR (near 1) indicates its use as a quantitative method. Real-time and quantitative PCR were sensitive and specific for the detection and quantification of M. suis in the blood of animals with acute and chronic form of eperythrozoonosis. Developed quantitative PCR cannot be used to detect carrier animals with a small amount of M. suis in their blood. The validity of real-time PCR used in the studies was confirmed by the low inter- and intra-assay coefficients of variation. This fact confirms the applicability of the assay in other laboratories.

Identification of Mycoplasma suis MSG1 interaction proteins on porcine erythrocytes.

Adhesion protein MSG1 mediating adherence to porcine erythrocytes in Mycoplasma suis (M. suis) invasion has been identified previously. In order to determine the host membrane proteins that interact with MSG1, recombinant His-tagged MSG1 (rMSG1) was used to screen for interacting proteins in the protein extracts of porcine erythrocyte membrane. Potential rMSG1-interacting proteins were initially identified as band 3 and β-actin with molecular weight of 46 and 45 kDa, respectively. Immune fluorescence results showed that rMSG1 can specifically bind with the β-actin of HeLa, BHK-21, and HEK-293A cells, respectively. RNA interference assays further demonstrated that the interaction between β-actin and rMSG1 on HeLa cells was specific and dose dependent. Confocal microscopy showed that both rMSG1 and M. suis can partially co-localize with β-actin on the surface of porcine erythrocytes. Pull-down assays showed that rMSG1 can directly interact with β-actin. Our study is the first to report the interaction of MSG1 with β-actin, which will be of help to understand the pathogenesis of M. suis and develop a cultivation system.

Identification of B cell epitopes in the MSG1 protein of Mycoplasma suis.

Mycoplasma suis (M. suis) is an extracellular bacterial organism that attaches to and causes deformity and damage to porcine red blood cells. M. suis glyceraldehyde-3-phosphate dehydrogenase-like protein 1 (MSG1), a membrane-associated adhesion protein, plays a major role in M. suis attachment and infection of porcine erythrocytes. In order to identify the epitopes in MSG1 protein of M. suis, recombinant MSG1 (rMSG1) expressed in Escherichia coli Top10 was purified with affinity chromatography and used to immunize BALB/c mice to prepare and screen monoclonal antibodies (MAbs). Western blot results showed that 1C10, 2F10, 4G10, and 10E9 can specifically react with recombinant MSG1 and M. suis. Moreover, 23 truncated fragments of MSG1 were amplified and cloned into pET-32a vector and induced by IPTG. Different recombinant truncated proteins were used to identify B cell epitopes in the rMSG1 protein. Epitope mapping revealed that MAb 1C10 recognizes the linear epitope D(291)THGSVF(297); MAb 2F10 recognizes the linear epitope L(251)CLKI(255); and MAbs 4G10 and 10E9 recognize the linear epitope I(268)KDGENE(274). The alignment of MSG1 epitope sequences with that of different M. suis strains accessed on NCBI showed that one epitope is highly conserved in M. suis strains. This research is the first to examine the epitopes in MSG1 of M. suis and demonstrate the variations of epitopes.

Interactive host cells related to Mycoplasma suis α-enolase by yeast two-hybrid analysis

Mycoplasma suis belongs to the haemotrophic mycoplasmas, which colonise the red blood cells of a wide range of vertebrates. Adhesion to red blood cells is the crucial step in the unique lifecycle of M. suis. In addition to MSG1 protein, α-enolase is the second adhesion protein of M. suis, and may be involved in the adhesion of M. suis to porcine red blood cells (RBC). To simulate the environment of the RBC, we established the cDNA library of swine peripheral blood mononuclear cells (PBMC). The yeast two-hybrid (Y2H) system was adopted to screen α-enolase interactive proteins in the PBMC line. Alignment with the NCBI database revealed four interactive proteins: beta-actin, 60S ribosomal protein L11, clusterin precursor and endonuclease/reverse transcriptase. However, the M. suis α-enolase interactive proteins in the PBMC cDNA library obtained in the current study provide valuable information about the host cell interactions of the M. suis α-enolase protein.

Seroprevalence and risk factors of Mycoplasma suis infection in pig farms in central China

Mycoplasma suis, the causative agent of porcine infectious anemia, causes large economic losses to the swine industry worldwide. A questionnaire-based survey was conducted in 69 pig farms in Hubei Province, China, from November 2011 to August 2013 to ascertain the prevalence and associated risk factors of M. suis. Four thousand and four blood samples from pigs of all the age groups were tested for M. suis antibodies using the established rMSG1–ELISA assay. Among these 4004 samples, 1615 blood samples from multiparous sows were examined to identify the association between seroprevalence and different seasons. Information on risk factors collected from farmers or attending veterinarians was recorded on a pre-designed questionnaire. The overall test seroprevalence of M. suis infection at the animal level was 31.9% (1277/4004; 95% CI: 30.5%, 33.4%), whereas at the farm level, this value was 95.65% (66/69; 95% CI: 87.8%, 99.1%). The seroprevalence of M. suis was higher in replacement gilts (40.6%; 95% CI: 35.1%, 46.3%), multiparous sows (48.2%; 95% CI: 45.8%, 50.7%) and boars (44.4%; 95% CI: 34.5%, 54.8%), as compared to piglets (13.0%; 95% CI: 9.4%, 17.3%), weaned-piglets (10.8%; 95% CI: 8.9%, 13.0%), and growing-finishing pigs (25.0%; 95% CI: 22.0%, 28.3%). In terms of seasons, the prevalence of M. suis in pigs was significantly higher in summer (65.3%; 95% CI: 61.0%, 69.5%) and autumn (65.0%; 95% CI: 59.0%, 70.6%) compared to spring (30.1%; 95% CI: 26.0%, 34.4%) and winter (36.4%; 95% CI: 31.4%, 41.5%). Farm-level risk factors were identified by multivariable logistic regression analysis. The associated factors retained in the final multivariable logistic regression model were drug treatment, presence of mosquitoes and flies, and frequency of disinfection. Drug treatment (OR=0.24; 95% CI: 0.07, 0.88; P=0.031) and frequency of disinfection (OR=0.23; 95% CI: 0.06, 0.90; P=0.035) were protective factors, and the presence of mosquitoes and flies (OR=5.994; 95% CI: 1.56, 23.00; P=0.009) was a risk factor for M. suis infection on farms. The results of the present study provide the first insight into the impact of associated determinants on M. suis infection in central China.

Quantitative PCR analysis of Mycoplasma suis shedding patterns during experimental infection

The uncultivable hemotrophic bacterium Mycoplasma suis causes infectious anemia in pigs worldwide. The mechanisms by which M. suis is transmitted from pig to pig are largely unknown. Thus, the present study aimed at investigating urine, feces, saliva, nasal and vaginal secrets as well as environmental samples for the presence of M. suis DNA to get insights into potential transmission routes. Seven pigs were experimentally infected with M. suis KI3806. Samples were taken for 8 days post infection (p.i.). A quantitative LightCycler msg1 PCR was used to detect and quantify M. suis. Shedding was found in saliva as well as nasal and vaginal secrets from day 6 p.i. on with a quantity of 3.4×102 to 2.7×105M. suis/swab. In urine M. suis DNA could be detected in 100.0% of the samples from day 6 p.i. on with a quantity of 4.7×102 to 6.3×105M. suis per mL. When shedding patterns were correlated to the median bacterial blood loads shedding was observed at loads of 2.0×109–7.0×1010M. suis per mL blood. No M. suis DNA could be amplified from feces. Dust and water samples of the pig drinking troughs were positive for M. suis on days 2 and 6 post infection, air samples were M. suis-negative throughout the experiment. Our results indicate that blood independent direct transmission as well as indirect transmission via environmental contamination could play a role in the epidemiology of M. suis infections.