Borrelia miyamotoi in Human-Biting Ticks, United States, 2013–2019

During 2013–2019, Borrelia miyamotoi infection was detected in 19 US states. Infection rate was 0.5%–3.2%; of B. miyamotoi–positive ticks, 59.09% had concurrent infections. B. miyamotoi is homogeneous with 1 genotype from Ixodes scapularis ticks in northeastern and midwestern states and 1 from I. pacificus in western states.

B orrelia miyamotoi, a relapsing fever group spirochete (1), was first isolated from Ixodes persulcatus ticks in Japan in 1995 (2) and later detected in Ixodes ticks in the United States and Europe (3)(4)(5). Although B. miyamotoi bacteria have been mainly detected in I. ricinus species complex ticks that transmit B. burgdorferi worldwide, the vector specificity needs further study because investigators have found B. miyamotoi in multiple tick species (6). B. miyamotoi has 3 geographically distinct genotypes: Asian, European, and American. In the United States, B. miyamotoi bacteria have been found in field-collected I. scapularis ticks in the northeastern and northern midwestern regions, where the average infection rate is 1.9% (7). However, an expanded geographic study of the prevalence of B. miyamotoi in human-biting ticks, its genotypes, and concurrent infections with other tickborne pathogens is warranted.
Human-biting ticks were submitted to the public tick testing program at the University of Massachusetts (Amherst, Massachusetts, USA) during May 2013-December 2019. We extracted DNA from individual ticks using the Epicenter Master Complete DNA and RNA Purification Kits (Lucigen, https:// www.lucigen.com). We performed a species-specific quantitative PCR (qPCR) for differentiation of I. scapularis and I. pacificus ticks (8). To detect Borrelia bacteria, we first applied a genus-specific detection assay, followed by specific qPCR assays for B. burgdorferi sensu lato and B. miyamotoi. We detected the tickborne pathogens Anaplasma phagocytophilum, Babesia microti, B. mayonii, and Ehrlichia muris-like agent (EMLA) by a multiplex qPCR assay targeting different genes. We used a qPCR assay targeting tick 16S mtDNA gene as an internal control (8). We sequenced 3 partial gene fragments, 16S rDNA (16S) (9), flagellin (fla) (6), and glycerophosphodiester phosphodiesterase (glpQ) (6), for B. miyamotoi samples that were positive by qPCR.
B. miyamotoi was found in 19 states; infection rates were 0.5%-3.2% (Figure). In the western  (5,9) was outside of our sequenced fla fragment (Appendix). The genetic identity between the 2 tick speciesspecific genotypes was 0.996 for fla and 0.986 for glpQ. Unlike heterogeneous B. burgdorferi populations, B. miyamotoi appears to be very homogeneous within its respective tick vectors.

About the Author
Dr. Xu is a research professor in the department of microbiology, University of Massachusetts-Amherst. His research interests include ticks and tickborne diseases.

Wohlfahrtiimonas chitiniclastica Monomicrobial Bacteremia in a Homeless Man
Omar Harfouch, Paul M. Luethy, Mandee Noval, Jonathan D. Baghdadi I n August 2020, a 63-year-old homeless man with a history of deep vein thrombosis and chronic venous insufficiency was found in his truck, unconscious and covered in feces and maggots. He reportedly had been parked in a single parking spot in rural Maryland, USA, for 3 days. His blood pressure in the field was too low to be quantified, and he was admitted to a community hospital in septic shock. Blood cultures were drawn before establishing intravenous access for administration of vancomycin, piperacillin/ tazobactam, and crystalloid. After being stabilized, he was transferred to our hospital, a tertiary care center in Baltimore, Maryland, USA, where surgeons performed superficial surgical debridement of his lower extremities and removed maggots by using a scrub brush with the patient under anesthesia in the operating room. We discarded the maggots, and they were not submitted for identification.
The patient's leukocyte count on arrival was 38.6 K/µL (reference range 4.5-11.0 K/µL), his creatinine 6.86 mg/dL (reference range 0.7-1.5 mg/ dL), and his lactic acid 3.5 mmol/L (reference range 0.5-2.2 mmol/L). He had elevated transaminases, an aspartate aminotransferase level of 436 U/L (reference range 17-59 U/L) and alanine transaminase of 174 U/L (reference range 0-49 U/L). A computed tomography scan of the lower extremities showed ulceration of the anterior right lower leg with edema and fat stranding of the subcutaneous tissue without fluid collection or gas. A magnetic resonance imaging of his left foot showed no evidence of osteomyelitis.
On day 2 of hospitalization, transient hemodynamic instability necessitated initiation of

RESEARCH LETTERS
We report a case of septic shock attributable to monomicrobial bloodstream infection secondary to Wohlfahrtiimonas chitiniclastica infection. This case suggests that W. chitiniclastica likely possesses the virulence to cause severe disease. Culture-independent techniques were essential in the identification of this organism, which enabled selection of appropriate therapy.