In Vitro Antimicrobial Susceptibility of Clinical Isolates of Borrelia miyamotoi

Abstract

is an emerging relapsing fever (RF) species that is reported to cause human disease in regions in which Lyme borreliosis is endemic. We recently showed that tick isolates are resistant to amoxicillin ; however, clinical isolates have not been studied. Therefore, our aim was to show the antimicrobial susceptibility of recently obtained clinical isolates of A dilution series of various antibiotics was made in modified Kelly-Pettenkofer medium with 10% fetal calf serum. The susceptibilities of different clinical, tick, RF , and 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 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 strains and tick isolates. All tested RF strains were susceptible to doxycycline (microscopic MIC range, 0.0625 to 0.25 mg/liter). In contrast to the MICs of the tested strains and in line with our previous findings, the amoxicillin MICs (range, 8 to 32 mg/liter) of all RF strains, including clinical isolates, were above the clinical breakpoint for resistance (≤4 mg/liter). Clinical isolates of are highly susceptible to doxycycline, azithromycin, and ceftriaxone Interestingly, as described previously for tick isolates, amoxicillin shows poor activity against clinical isolates.

Prevalence and clinical manifestation of Borrelia miyamotoi in Ixodes ticks and humans in the northern hemisphere: a systematic review and meta-analysis

“…Therefore, the disease is empirically treated on the basis of the guidelines for Lyme borreliosis and relapsing fever Borreliae. 59 Published cases were most frequently treated with doxycycline and ceftriaxone. In the 333 (66%) cases that addressed the method of treatment and recovery, all reported successful treatment with antibiotics.…”

Borrelia miyamotoi infection leads to cross-reactive antibodies to the C6 peptide in mice and men

“…To date, little is known about the burden of BMD and little is known about the long-term effects of infection with B. miyamotoi. Although treatment regimens for both diseases and antimicrobial susceptibility of both pathogens are similar [18,19], it is important to be able to differentiate between these diseases. Based on the above, we aimed to determine C6 EIA crossreactivity in silico, in experimentally B. miyamotoi-infected mice and in PCR-proven BMD patients from Russia.…”

Pathogenesis of Relapsing Fever

“…Although human exposure to, and infection with, B. miyamotoi appears to occur regularly (Jahfari et al, 2016;Kadkhoda et al, 2017;Krause et al, 2014;Sarksyan et al, 2015b;Sato et al, 2018;Smith et al, 2019;Wroblewski et al, 2017), human B. miyamotoi disease (BMD) is relatively infrequent. Nonetheless, case reports and case series of human BMD have been described in Europe, Asia and North America, with a considerable amount of cases originating from Russia and the United States (Chowdri et al, 2013;Crowder et al, 2014;Hoornstra et al, 2018;Jiang et al, 2018;Jobe et al, 2016;Karan et al, 2018;Koetsveld et al, 2017b;Krause et al, 2013;Krause et al, 2016;Molloy et al, 2015;Platonov et al, 2011;Sarksyan et al, 2015a;Sarksyan et al, 2015b;Sato et al, 2014;Sudhindra et al, 2016;Yamano et al, 2017). Generally, the clinical presentation is rather indistinct, but is characterized by fever a few days to weeks after a tick bite, accompanied by non-specific influenza-like symptoms, including chills, fatigue, headache, myalgia and arthralgia (Platonov et al, 2011).…”

“…Therefore, additional antigens, including Vmps, have been investigated (Wagemakers et al, 2016) (Hoornstra et al, 2018;Sudhindra et al, 2016). Additionally, in vitro analysis indicated that B. miyamotoi laboratory strains and Russian clinical isolates are susceptible to doxycycline, azithromycin, and ceftriaxone (Koetsveld et al, 2017a;Koetsveld et al, 2018b). In these studies, a (relative) resistance to amoxicillin was shown.…”