We determined the frequency of isolation of staphylococcal small-colony variants (SCVs) from 31 culture-positive patients undergoing revision of total hip prosthesis for aseptic loosening or presumed prosthetic-joint infection (PJI). We analysed auxotrophy of cultured SCVs, their antimicrobial susceptibility profiles and their biofilm-forming capacity. Eight SCV strains were cultivated from six (19 %) patients. All SCVs were coagulase-negative staphylococci (CNS) with Staphylococcus epidermidis as the predominant species; there was also one Staphylococcus warneri SCV. The SCVs were auxotrophic for haemin, with one strain additionally auxotrophic for menadione. We noted the presence of two phenotypically (differences concerning antimicrobial susceptibility) and genetically distinct SCV strains in one patient, as well as the growth of two genetically related SCVs that differed in terms of their morphology and the type of auxotrophy in another. Seven out of eight SCVs were resistant to meticillin and gentamicin. In addition, antibiotic sensitivity testing revealed three multidrug-resistant SCV-normal-morphology isolate pairs. One S. epidermidis SCV harboured icaADBC genes and was found to be a proficient biofilm producer. This paper highlights the involvement of CNS SCVs in the aetiology of PJIs, including what is believed to be the first report of a S. warneri SCV. These subpopulations must be actively sought in the routine diagnosis of implant-associated infections. Moreover, in view of the phenotypic and genetic diversity of some SCV pairs, particular attention should be paid to the investigation of all types of observed colony morphologies, and isolates should be subjected to antimicrobial susceptibility testing.

Staphylococcus epidermidis is commonly involved in biomaterial-associated infections. Bacterial small colony variants (SCV) seem to be well adapted to persist intracellularly in professional phagocytes evading the host immune response. We studied the expression of PD-L1/L2 on macrophages infected with clinical isolates of S. epidermidis SCV and their parent wild type (WT) strains. The cytokine pattern which is triggered by the examined strains was also analysed. In the study, we infected macrophages with S. epidermidis WT and SCV strains. Persistence and release from macrophages were monitored via lysostaphin protection assays. Moreover, the effect of IFN-γ pre-treatment on bacterial internalisation was investigated. Expression of PD-L1/L2 molecules was analysed with the use of FACS. Inflammatory reaction was measured by IL-10, TNF-α ELISAs, and transcriptional induction of TNF-α. Our study revealed that clinical SCV isolates were able to persist and survive in macrophages for at least 3 days with a low cytotoxic effect and a reduced proinflammatory response as compared to WT strains. Bacteria upregulated PD-L1/L2 expression on macrophages as compared to non-stimulated cells. The results demonstrated that the ability of S. epidermidis SCVs to induce elevated levels of anti-inflammatory cytokine, IL-10, and reduced transcriptional induction of TNF-α, together with expression of PD-L1 on macrophages and the ability to persist intracellularly without damaging the host cell could be the key factor contributing to chronicity of SCV infections.

The risk of occupational exposure to the B. burgdorferi infection is high for foresters and farmers, and the infection with spirochetes is frequently confirmed on the basis of positive results of the Wb test. The presence of specific antibodies against protein antigens of B. spielmanii and B. bavariensis suggest that these bacteria can cause Lyme disease both independently and in participation with other Borrelia species, which influences the development of the clinical manifestations of infection.

Background. Lyme borreliosis is the most frequent tick-borne disease in Europe and North America, and the number of registered cases is on the increase. Frequent presence in the habitats of ticks enhances the risk of tick bites and possible infection with Borrelia burgdorferi spirochetes. Objective. The aim of the study was to assess the risk of B. burgdorferi infection posed to hunters and other individuals exposed to activity-related contact with ticks. Material and methods. The study was carried out in the northern part of the Lublin Province (eastern Poland) and involved 150 individuals exposed to tick bites (110 hunters and 40 individuals exposed to activity-related contact with ticks). The analysis of sera for the presence of B. burgdorferi IgM and IgG antibodies was carried out. All 150 individuals were tested with the ELISA assay, and positive and borderline results of the assay were verified with the Western blot test. All study participants completed a questionnaire, which provided information about exposure to ticks, application of prophylactic measures, and awareness of Lyme borreliosis. Results. The ELISA assay revealed a positive or borderline result in at least one of the classes of B. burgdorferi antibodies in 63.3% (95/150) of the individuals (IgM 14.0%, IgG 63.3%). Verification carried out with the Western blot test showed a positive or borderline result in at least one of the antibody classes in 38.0% (57/150) of the examined persons (IgM 2.7%, IgG 36.7%). Abdomen (56.0%) and legs (53.7%) were the most frequently bitten body regions. Tick bites on the abdomen were significantly more frequently declared by hunters. Inspection of the body after returning from natural areas was more popular prophylactic method than use of repellents. Inspection of the body was significantly more often used in the group of the hunters. Conclusions. The risk of B. burgdorferi infection among hunters and other individuals undertaking activities associated with exposure to tick bites in the study area is high. STRESZCZENIEWprowadzenie. Borelioza z Lyme jest najczęstszą chorobą przenoszoną przez kleszcze w Europie i Ameryce Północnej, a liczba rejestrowanych przypadków zachorowań wzrasta. Częsta obecność w siedliskach kleszczy zwiększa ryzyko ukłucia przez kleszcze i możliwe zakażenie krętkami Borrelia burgdorferi. Cel badań. Celem badań była ocena ryzyka zakażenia B. burgdorferi wśród myśliwych oraz innych osób podejmujących aktywności narażające na kontakt z kleszczami. Materiał i metoda. Badania przeprowadzono na terenie północnej części województwa lubelskiego (wschodnia Polska) wśród 150 osób narażonych na pokłucia przez kleszcze (110 myśliwych i 40 osób narażonych na kontakt z kleszczami w związku z podejmowaniem innych aktywności). Zbadano surowice w kierunku obecności przeciwciał IgM i IgG anty--Borrelia burgdorferi. U wszystkich 150 osób wykonano test ELISA, a pozytywne i wątpliwe wyniki tego testu zweryfikowano stosując test Western blot. W badaniach zastosowano również autorski kwestionariusz ankiety do ocen...

IntroductionLyme borreliosis/Lyme disease is caused by Borrelia burgdorferi and is one of the most common vector-borne diseases transmitted by ticks.Material and MethodsA total of 136 Ixodes ricinus ticks, collected in the Ternopil (Ukraine) region, including 126 adults (70 females and 56 males), and 10 nymphs were examined. The identification of the species and their developmental form was based on morphological characteristics.ResultsPCR with B5S-Bor and 23S-Bor primers resulted in Borrelia burgdorferi sensu lato DNA amplification among six ticks (4.4%). The detailed analysis based on the DNA sequencing showed the presence of DNA of Borrelia afzelii in four samples; the remaining two represented Borrelia burgdorferi sensu lato complex, although their genospecies were not determined. The research confirmed the dominance of Borrelia afzelii genospecies in the ticks from Ukraine.ConclusionIt seems reasonable to undertake similar research in ticks from other regions of Ukraine. Knowledge in this field can be useful for public health and planning the prevention of tick-borne diseases.