Search tips
Search criteria

Results 1-8 (8)

Clipboard (0)

Select a Filter Below

Year of Publication
Document Types
1.  Comparison of fecal culture and F57 real-time polymerase chain reaction for the detection of Mycobacterium avium subspecies paratuberculosis in Swiss cattle herds with a history of paratuberculosis 
Bovine paratuberculosis is an incurable chronic granulomatous enteritis caused by Mycobacterium avium subspecies paratuberculosis (MAP). The prevalence of MAP in the Swiss cattle population is hard to estimate, since only a few cases of clinical paratuberculosis are reported to the Swiss Federal Food Safety and Veterinary Office each year.
Fecal samples from 1,339 cattle (855 animals from 12 dairy herds, 484 animals from 11 suckling cow herds, all herds with a history of sporadic paratuberculosis) were investigated by culture and real-time polymerase chain reaction (PCR) for shedding of MAP.
By culture, MAP was detected in 62 of 445 fecal pools (13.9%), whereas PCR detected MAP in 9 of 445 pools (2.0%). All 186 samples of the 62 culture-positive pools were reanalyzed individually. By culture, MAP was grown from 59 individual samples (31.7%), whereas PCR detected MAP in 12 individual samples (6.5%), all of which came from animals showing symptoms of paratuberculosis during the study. Overall, MAP was detected in 10 out of 12 dairy herds (83.3%) and in 8 out of 11 suckling cow herds (72.7%).
There is a serious clinically inapparent MAP reservoir in the Swiss cattle population. PCR cannot replace culture to identify individual MAP shedders but is suitable to identify MAP-infected herds, given that the amount of MAP shed in feces is increasing in diseased animals or in animals in the phase of transition to clinical disease.
PMCID: PMC4197246  PMID: 25300710
Mycobacterium avium subspecies paratuberculosis; Cattle; Feces; Culture; PCR
2.  Surveillance of Bovine Tuberculosis and Risk Estimation of a Future Reservoir Formation in Wildlife in Switzerland and Liechtenstein 
PLoS ONE  2013;8(1):e54253.
Bovine tuberculosis (bTB) caused by Mycobacterium bovis or M. caprae has recently (re-) emerged in livestock and wildlife in all countries bordering Switzerland (CH) and the Principality of Liechtenstein (FL). Comprehensive data for Swiss and Liechtenstein wildlife are not available so far, although two native species, wild boar (Sus scrofa) and red deer (Cervus elaphus elaphus), act as bTB reservoirs elsewhere in continental Europe. Our aims were (1) to assess the occurrence of bTB in these wild ungulates in CH/FL and to reinforce scanning surveillance in all wild mammals; (2) to evaluate the risk of a future bTB reservoir formation in wild boar and red deer in CH/FL. Tissue samples collected from 2009 to 2011 from 434 hunted red deer and wild boar and from eight diseased ungulates with tuberculosis-like lesions were tested by direct real-time PCR and culture to detect mycobacteria of the Mycobacterium tuberculosis complex (MTBC). Identification of suspicious colonies was attempted by real-time PCR, genotyping and spoligotyping. Information on risk factors for bTB maintenance within wildlife populations was retrieved from the literature and the situation regarding identified factors was assessed for our study areas. Mycobacteria of the MTBC were detected in six out of 165 wild boar (3.6%; 95% CI: 1.4–7.8) but none of the 269 red deer (0%; 0–1.4). M. microti was identified in two MTBC-positive wild boar, while species identification remained unsuccessful in four cases. Main risk factors for bTB maintenance worldwide, including different causes of aggregation often resulting from intensive wildlife management, are largely absent in CH and FL. In conclusion, M. bovis and M. caprae were not detected but we report for the first time MTBC mycobacteria in Swiss wild boar. Present conditions seem unfavorable for a reservoir emergence, nevertheless increasing population numbers of wild ungulates and offal consumption may represent a risk.
PMCID: PMC3549981  PMID: 23349839
3.  Complete Genome Sequence of the Hemotrophic Mycoplasma suis Strain KI3806▿ 
Journal of Bacteriology  2011;193(9):2369-2370.
Mycoplasma suis, a member of the hemotrophic mycoplasma (HM) group, parasitize erythrocytes of pigs. Increasing evidence suggests that M. suis is also a zoonotic agent. Highly pathogenic strains of M. suis (e.g., M. suis KI3806) have been demonstrated to invade erythrocytes. This complete sequenced and manually annotated genome of M. suis KI3806 is the first available from this species and from the HM group. The DNA was isolated from blood samples of experimentally infected pigs due to the lack of an in vitro cultivation system. The small circular chromosome of 709,270 bp, encoding an unexpectedly high number of hypothetical proteins and limited transport and metabolic capacities, could reflect the unique lifestyle of HM on the surface of erythrocytes.
PMCID: PMC3133081  PMID: 21398558
4.  In vivo transmission studies of ‘Candidatus Mycoplasma turicensis’ in the domestic cat 
Veterinary Research  2009;40(5):45.
The natural transmission routes of the three feline haemotropic mycoplasmas – Mycoplasma haemofelis, ‘Candidatus Mycoplasma haemominutum’, and ‘Candidatus Mycoplasma turicensis’ (CMt) – are largely unknown. Since CMt has been detected in the saliva of infected cats using PCR, we hypothesised that direct transmission via social or aggressive contact may occur. The aim of this study was to evaluate this transmission route. CMt-positive saliva and blood samples were obtained from three prednisolone-treated specific pathogen-free (SPF) cats that were infected intraperitoneally with CMt. Five SPF cats were inoculated with CMt-positive saliva or blood subcutaneously to mimic cat bites, and five cats were inoculated orally with blood or oronasally with saliva to mimic social contact. Blood samples were monitored for CMt infection using quantitative real-time PCR and for seroconversion using a novel western blot assay. Neither oronasal nor subcutaneous inoculation with CMt-positive saliva led to CMt infection in the recipient cats, as determined by PCR, independent of prior prednisolone treatment. However, when blood containing the same CMt dose was given subcutaneously, 4 of the 5 cats became PCR-positive, while none of the 5 cats inoculated orally with up to 500 μL of CMt-positive blood became PCR-positive. Subsequently, the latter cats were successfully subcutaneously infected with blood. All 13 CMt-exposed cats seroconverted. In conclusion, CMt transmission by social contact seems less likely than transmission by aggressive interaction. The latter transmission may occur if the recipient cat is exposed to blood from an infected cat.
PMCID: PMC2701178  PMID: 19505421
haemotropic mycoplasma; transmission; ‘Candidatus Mycoplasma turicensis’; real-time TaqMan PCR; seroconversion
5.  Inorganic pyrophosphatase in uncultivable hemotrophic mycoplasmas: identification and properties of the enzyme from Mycoplasma suis 
BMC Microbiology  2010;10:194.
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.
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.
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.
PMCID: PMC2916918  PMID: 20646294
6.  Follow-up of Bernese Mountain dogs and other dogs with serologically diagnosed Borrelia burgdorferi infection: What happens to seropositive animals? 
Data on the long-term outcome of B. burgdorferi infections in adult dogs are sparse. The aim of the present study was to investigate whether Bernese Mountain dogs with serological evidence of natural B. burgdorferi infection more often develop signs such as lameness, azotemia or proteinuria during a follow-up period of 2.5 to 3.0 years. Seropositive Bernese Mountain dogs were compared to seronegative Bernese Mountain dogs and to seropositive and seronegative control dogs of other breeds.
Dogs included in a previous study on the prevalence of antibodies against B. burgdorferi in Bernese Mountain dogs were re-evaluated. Antibodies against B. burgdorferi were determined using an ELISA with a whole-cell sonicate as antigen and results were confirmed using a Western blot assay.
Fifty-three Bernese Mountain dogs and 30 control dogs were re-evaluated. Re-evaluation was performed between 2.5 and 3.0 years (median 2.7 years) after the first assessment.
The age of the dogs at the second evaluation ranged from 3 to 11 years (median 6 years). There were no significant differences with regard to poor general condition or lameness between the first and the second evaluation.
At the first evaluation 22 (42%) of the Bernese Mountain dogs and 11 (37%) of the control dogs were considered positive for antibodies against B. burgdorferi. At the second evaluation 25 (47%) of the Bernese Mountain dogs and 12 (40%) of the control dogs were considered positive; 69% of the dogs showed the same serological result at both examinations and 31% were seroconverted or seroreverted. During the first examination, azotemia was diagnosed in 6 Bernese Mountain dogs and during the second examination in 11 Bernese Mountain dogs. No control dogs had azotemia in this study. In seropositive dogs there was no increase in lameness or signs of renal disease over time.
It may be concluded that antibodies against B. burgdorferi determined by whole cell ELISA and confirmed by Western blot were neither associated with the development of lameness nor with signs of renal disease like azotemia or proteinuria in dogs observed over a period of 2.5 to 3.0 years.
PMCID: PMC2697146  PMID: 19426490
7.  Use of Recombinant Antigens To Detect Antibodies against Mycoplasma suis, with Correlation of Serological Results to Hematological Findings▿  
Clinical and Vaccine Immunology : CVI  2007;14(12):1616-1622.
Porcine eperythrozoonosis is a disease with worldwide distribution caused by the unculturable hemotrophic bacterium Mycoplasma suis. Current serological testing utilizes crude M. suis antigens purified from the blood of experimentally infected pigs. These antigens show high variability and are restricted to specialized laboratories. We evaluated a novel serological assay based on two recombinant M. suis antigens (rMSG1 and rHspA1). Antigen specificity was proven by means of sera raised against nonhemotrophic mycoplasma and other relevant bacteria. Using experimental and convalescent-phase sera, rMSG1 and rHspA1 enzyme-linked immunosorbent assays (ELISAs) demonstrated sensitivities, specificities, and predictive values (94.0 to 100.0%) equal to or higher than those of the M. suis whole-cell ELISA. Field samples from 120 weaning piglets grouped by quantitative PCR results were used to evaluate the diagnostic capability of the new ELISA systems in comparison to that of the whole-cell ELISA. Assuming a 100.0% specificity of the PCR, the whole-cell ELISA, rHspA1 ELISA, and rMSG1 ELISA showed specificities of 84.8%, 83.8%, and 90.6% and sensitivities of 61.5%, 74.0% and 58.1%, respectively. Cohen's kappa coefficients comparing the recombinant ELISAs to the whole-cell ELISA indicate moderate to substantial agreement. The detection of anti-MSG1 and/or anti-HspA1 antibodies in pigs was significantly correlated with decreased hematocrit, erythrocyte numbers, and hemoglobin concentrations, indicating that a single seropositive result is connected with clinical and etiological significance. In conclusion, rMSG1 and rHspA1 are sensitive and specific serological and infection markers which are for the first time used independently of animal experiments. They are especially fit to be used in routine diagnosis, pathogenesis studies, and large-scale epidemiological investigations.
PMCID: PMC2168379  PMID: 17942612
8.  Increased prevalence of Borrelia burgdorferi infections in Bernese Mountain Dogs: a possible breed predisposition 
Glomerulonephritis in dogs has been associated with B. burgdorferi infections. In Bernese Mountain Dogs with glomerulonephritis antibodies against B. burgdorferi have been found in most dogs, raising the question if the breed is predisposed to infections with B. burgdorferi. The aim of this study was to determine the prevalence of antibodies against B. burgdorferi sensu lato in a well defined population of Bernese Mountain Dogs and to compare this prevalence with data from dogs of other breeds.
160 Bernese Mountain Dogs and 62 control dogs (large breed dogs with long hair) were included. All dogs were considered healthy according to a questionnaire filled out by the owner, complete blood count, chemistry panel, urinalysis and urine culture. Bernese Mountain Dogs and control dogs were kept in similar environments. Seroprevalence of B. burgdorferi was assessed by ELISA and Western blot and was 58% in Bernese Mountain Dogs compared to 15% in control dogs. This difference was significant. Neither antibodies against leptospires nor vaccination or hair coat color influenced the results.
The cause of the considerably higher prevalence of antibodies against B. burgdorferi in Bernese Mountain Dogs and it's consequences are not known. A breed predisposition can be suspected.
PMCID: PMC1959192  PMID: 17626630

Results 1-8 (8)