Humans Infected with Relapsing Fever Spirochete Borrelia miyamotoi, Russia

Disease may occur throughout the world because of the widespread prevalence of this pathogen in ixodid ticks

Clinical features of myasthenia gravis in elderly and senile patients

The prevalence of myasthenia gravis is 10-24 cases per 100, 000 population. The debut of the disease is possible at any age: from infancy to old age. In the literature, the definition of “myasthenia gravis with late onset” – at the age of 60 years and older, which is 20-46% of all cases. In this regard, the disease is often combined with a burdened somatic history, which makes it difficult to timely diagnosis and treatment. This group of elderly patients accounts for the majority of diagnostic errors in the diagnosis of myasthenia gravis. This study is devoted to the study of the features of the onset and course of myasthenia gravis in elderly and senile people

Dynamics of Spirochetemia and Early PCR Detection of Borrelia miyamotoi

We investigated whether Borrelia miyamotoi disease can be detected in its early stage by using PCR for borrelial 16S rRNA, which molecule (DNA or RNA) is the best choice for this test, and whether spirochetes are present in blood during the acute phase of B. miyamotoi disease. A total of 473 patients with a suspected tickborne infection in Yekaterinburg, Russia, in 2009, 2010, and 2015 were enrolled in this study. Blood samples were analyzed by using quantitative PCR or ELISA, and a diagnosis of borreliosis was confirmed for 310 patients. For patients with erythema migrans, 5 (3%) of 167 were positive for B. miyamotoi by PCR; for patients without erythema migrans, 65 (45%) of 143 were positive for B. miyamotoi by PCR. The median concentration for RNA was 3.8 times that for DNA. Median time for detection of B. miyamotoi in blood was 4 days

Development and optimization of an in vitro cultivation protocol allows for isolation of Borrelia miyamotoi from patients with hard tick-borne relapsing fever

Objectives: Borrelia miyamotoi has been shown to infect humans in Eurasia and North America causing hard tick-borne relapsing fever (HTBRF). In vitro cultivation of B. miyamotoi was described recently; but clinical isolation of relapsing fever Borrelia is cumbersome. Our aim was to develop a straightforward protocol enabling B. miyamotoi isolation directly from the blood of patients. Methods: Modified Kelly-Pettenkorfer (MKP-F) medium, with or without anticoagulants, or blood from healthy human volunteers, was spiked with B. miyamotoi spirochaetes in vitro. Subsequently, either media or plasma was used for cultivation directly, or after an additional centrifugation step. This isolation protocol was tested in a clinical setting on patients suspected of HTBRF. Results: Dipotassium-EDTA, trisodium citrate and lithium heparin inhibited growth of B. miyamotoi at concentrations similar to 250 mg/mL, 2.5 mM and 1 IU/mL, respectively. However, when plasma originating from human blood containing B. miyamotoi spirochaetes was subjected to an additional centrifugation step at 8000 g, suspended and inoculated into fresh MKP-F media, positive cultures were observed within 2 weeks. Of importance, this straightforward protocol allowed for isolation of B. miyamotoi from six out of nine patients with confirmed HTBRF. Conclusions: Direct culture from K2-EDTA, trisodium citrate and lithium heparin plasma containing B. miyamotoi is hampered due to anticoagulants. Using a simple centrifugation protocol we were able to circumvent this detrimental effect, allowing for the first clinical isolation of B. miyamotoi. This will be of value for future research on the pathogenesis, genetics, diagnosis, therapy and epidemiology of HTBRF and other tick-borne relapsing fevers. (C) 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserve

In vitro antimicrobial susceptibility of clinical isolates of borrelia miyamotoi

Borrelia miyamotoi is an emerging relapsing fever (RF) Borrelia species that is reported to cause human disease in regions in which Lyme borreliosis is endemic. We recently showed that B. miyamotoi tick isolates are resistant to amoxicillin in vitro; however, clinical isolates have not been studied. Therefore, our aim was to show the antimicrobial susceptibility of recently obtained clinical isolates of B. miyamotoi. A dilution series of various antibiotics was made in modified Kelly-Pettenkofer medium with 10% fetal calf serum. The susceptibilities of different B. miyamotoi clinical, B. miyamotoi tick, RF Borrelia, and Borrelia burgdorferi sensu lato isolates were tested by measuring MICs through colorimetric changes and by counting motile spirochetes by dark-field microscopy after 72 h of incubation. The ceftriaxone and azithromycin MIC ranges of the six B. miyamotoi clinical isolates tested were 0.03 to 0.06 mg/liter and 0.0016 to 0.0032 mg/liter, respectively. These values are similar to MICs for RF Borrelia strains and B. miyamotoi tick isolates. All tested RF Borrelia strains were susceptible to doxycycline (microscopic MIC range, 0.0625 to 0.25 mg/liter). In contrast to the MICs of the tested B. burgdorferi sensu lato strains and in line with our previous findings, the amoxicillin MICs (range, 8 to 32 mg/liter) of all RF Borrelia strains, including B. miyamotoi clinical isolates, were above the clinical breakpoint for resistance (4 mg/liter). Clinical isolates of B. miyamotoi are highly susceptible to doxycycline, azithromycin, and ceftriaxone in vitro. Interestingly, as described previously for tick isolates, amoxicillin shows poor in vitro activity against B. miyamotoi clinical isolates

Borrelia miyamotoiClinical Strains Isolated in Russia

B. miyamotoistrain FR64