Characterization of Borrelia burgdorferi sensu lato strains isolated from human material in Slovenia

The aim of the study was to assess genotypic and phenotypic diversity among a large number of clinical isolates of Borrelia burgdorferi sensu lato obtained from patients in Slovenia. Plasmid profiles and species identification were determined by PFGE, protein profiles by SDS-PAGE. Of 706 B. burgdorferi sensu lato human isolates 599 (85%) were found to be B. afzelii, 101 (14%) B. garinii and six (1%) B. burgdorferi sensu stricto. The vast majority of strains (605; 86%) were isolated from skin, 58 (8%) from blood, and 43 (6%) from CSF. When analysed by RFLP, B. afzelii strains were unique, while heterogeneity was found within B. garinii and B. burgdorferi sensu stricto species. An unusual plasmid content was found in 52/706 (7%) isolated strains, more often in B. garinii than in B. afzelii strains. A plasmid dimer was found in B. afzelii and B. garinii strains, whereas multiple copies of the large plasmid were associated nearly exclusively with B. garinii strains. Analysis of protein profiles revealed that OspA and OspB are expressed more often by B. afzelii strains, and OspC by B. garinii strains. Heterogeneity of Borrelia strains may play a significant role in the virulence and pathogenesis of the infection. Differences in antigenic components have an important impact on serological testing and vaccine development.     

Epidemiological,clinical and laboratory distinction between human granulocytic ehrlichiosis and the initial phase of tick-borne encephalitis

OBJECTIVE: To establish epidemiological, clinical and laboratory differences between adult patients with proven acute human granulocytic ehrlichiosis (HGE) and patients with the initial phase of tick-borne encephalitis (TBE). METHODS: Epidemiological, clinical and laboratory findings were compared in nine patients with acute HGE (established by the presence of specific DNA sequences of Ehrlichia phagocytophila in whole blood by polymerase chain reaction and/or by seroconversion or at least a four-fold change of serum antibody titres to E. phagocytophila by indirect immunofluorescence assay) and 29 patients with the initial phase of TBE (demonstrated in ELISA tests by the presence of serum IgM antibodies to TBE virus). RESULTS: Findings were similar for the majority of the general parameters examined, which included sex, age, incubation period, duration of fever, and frequency of additional tick bites. However, a statistically significant difference was found for the duration of fever before the first visit (median 7 days in patients with acute HGE and 4 days in patients with the initial phase of TBE; p = 0.0169), and for the frequency of hospitalisation, which was higher for patients with the initial phase of TBE (29/29) than for those with acute HGE (5/9; p = 0.0017). Comparison of clinical signs and symptoms and laboratory findings in the two groups revealed significant differences: in patients with acute HGE there was a higher frequency of chills (4/9 versus 3/29, respectively; p = 0.0407), myalgia (8/9 versus 13/29, respectively; p = 0.0263), and arthralgia (7/9 versus 3/29, respectively; p = 0.0003), and elevated values of lactate dehydrogenase (7/9 versus 3/29, respectively; p = 0.0003) and concentration of C-reactive protein (9/9 versus 6/29, respectively; p = 0.0000). CONCLUSIONS: In a patient with febrile illness occurring after a tick bite, a clinical report of chills, myalgia and arthralgia, and laboratory findings of elevated values for lactate dehydrogenase and concentration of C-reactive protein direct towards a diagnosis of acute HGE rather than the initial phase of TBE.     

Transmission of Mycobacterium tuberculosis from human to cattle

We describe the first transmission of Mycobacterium tuberculosis from human to cattle confirmed by molecular typing of isolates involved in the transmission. IS6110-based restriction fragment length polymorphism analysis showed that the isolates from the cattle and farm worker who suffered from pulmonary tuberculosis 1 year prior to this case were the same strains.     

Is the ABO incompatibility a risk factor in bone marrow transplantation?

ABO histo-bloodgroups are strong transplantation antigens. In bone marrow transplantation, foreign ABO red cell antigens are not ignored by the immune system of the host, neither by the immunocompetent cells of the graft. Although ABO incompatibility is not considered a contraindication in bone marrow transplantation (BMT), its clinical consequences are still a matter of investigation. An overview of reports published by different groups is given and discussed. They present conflicting data regarding the role of the ABO match between patient and donor in the haematopoietic stem cell (HSC) transplantation. We report on the clinical outcome of bone marrow transplantation in 223 patients who received grafts from MHC identical siblings. Included are 139 ABO identical, 32 ABO minor mismatched, 34 major mismatched and 13 bi-directionally mismatched pairs. The statistical evaluation of standard parameters used to monitor the post-transplant period gave a proof that in neither group of patients with an ABO incompatible donor the recovery and success rate of transplantation, including the relapse incidence, risk of graft vs. host disease (GVHD) or overall survival, were significantly inferior. However, in all three cohorts of ABO mismatched patients, a delayed recovery of neutrophils was recorded as compared to the group receiving an ABO compatible graft. These finding leads us to the conclusion that the ABO compatibility is not a disadvantage in BMT, whereas the delayed recovery of neutrophils in patients having received an ABO mismatched graft is probably reflecting a transient humoral process leading to immune tolerance and graft accommodation.     

MD-2 and Der p 2 - a tale of two cousins or distant relatives?

MD-2, an LPS-binding protein is essential for the recognition of LPS by TLR4. MD-2 belongs to the ML superfamily of lipid-binding proteins. The tertiary structure of mite allergen protein Der p 2 was identified as having the protein fold most compatible with the sequence of MD-2. Comparison of MD-2 and Der p 2 reveals that they have many common biochemical characteristics: they are both rich in beta-structure and they are both very stable proteins as they both unfold only above 90 degrees C. In Der p 2, six cysteine residues form three disulfide bridges. We determined one free cysteine residue per recombinant biologically active MD-2 molecule, supporting similar disulfide topology with three disulfides bridges as in Der p 2. MD-2 binds LPS with high affinity; however, only weak binding of LPS was detected with Der p 2. Comparison of electrostatic potentials of the structural model of MD-2 and Der p 2 indicates a region of high positive potential on MD-2 and its absence in Der p 2, which may be the reason for its weak binding of LPS. We suggest that Der p 2 and its homologues probably do not have a role in response to Gram-negative bacteria in insects and that MD-2 family members with their specific role in innate immunity probably evolved from an ML ancestor only in higher vertebrates.     

Molecular characterization of Staphylococcus aureus isolates from skin and soft tissue infections samples and healthy carriers in the Central Slovenia region

Staphylococcus aureus is among the most important human pathogens. It is associated with different infections and is a major cause of skin and soft tissue infections (SSTIs). The aim of our study was to compare S. aureus isolates associated with SSTIs with isolates obtained from healthy carriers in the Central Slovenia region in terms of antimicrobial susceptibility, genetic diversity by clonal complex (CC)/sequence type, spa type, and by toxin gene profiling. In total, 274 S. aureus isolates were collected prospectively by culturing wound samples from 461 SSTI patients and nasal samples from 451 healthy carriers. We have demonstrated high heterogeneity in terms of CCs and spa type in both groups of isolates. The main clone among SSTI strains was Panton–Valentine leukocidin gene (pvl) positive CC121, whereas the main clone among carrier strains was CC45 carrying a large range of toxin genes. The main spa type in both groups was t091. Pvl was more frequently present in SSTI strains (31.2% SSTI vs 3.6% carrier strains) and staphylococcal enterotoxin C was more frequently present in carrier strains (1.6% SSTI vs 17.0% carrier strains). We have also demonstrated that methicillin‐resistant S. aureus was a rare cause (2.8%) of SSTIs in our region.