TY - JOUR

T1 - Isolation and propagation of laboratory strains and a novel flea-derived field strain of Wolbachia in tick cell lines

AU - Khoo, Jing Jing

AU - Kurtti, Timothy J.

AU - Husin, Nurul Aini

AU - Beliavskaia, Alexandra

AU - Lim, Fang Shiang

AU - Zulkifli, Mulya Mustika Sari

AU - Al-Khafaji, Alaa M.

AU - Hartley, Catherine

AU - Darby, Alistair C.

AU - Hughes, Grant L.

AU - Abubakar, Sazaly

AU - Makepeace, Benjamin L.

AU - Bell-Sakyi, Lesley

N1 - Publisher Copyright: © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2020/7

Y1 - 2020/7

N2 - Wolbachia are intracellular endosymbionts of several invertebrate taxa, including insects and nematodes. Although Wolbachia DNA has been detected in ticks, its presence is generally associated with parasitism by insects. To determine whether or not Wolbachia can infect and grow in tick cells, cell lines from three tick species, Ixodes scapularis, Ixodes ricinus and Rhipicephalus microplus, were inoculated with Wolbachia strains wStri and wAlbB isolated from mosquito cell lines. Homogenates prepared from fleas collected from cats in Malaysia were inoculated into an I. scapularis cell line. Bacterial growth and identity were monitored by microscopy and PCR amplification and sequencing of fragments of Wolbachia genes. The wStri strain infected Ixodes spp. cells and was maintained through 29 passages. The wAlbB strain successfully infected Ixodes spp. and R. microplus cells and was maintained through 2–5 passages. A novel strain of Wolbachia belonging to the supergroup F, designated wCfeF, was isolated in I. scapularis cells from a pool of Ctenocephalides sp. cat fleas and maintained in vitro through two passages over nine months. This is the first confirmed isolation of a Wolbachia strain from a flea and the first isolation of any Wolbachia strain outside the “pandemic” A and B supergroups. The study demonstrates that tick cells can host multiple Wolbachia strains, and can be added to panels of insect cell lines to improve success rates in isolation of field strains of Wolbachia.

AB - Wolbachia are intracellular endosymbionts of several invertebrate taxa, including insects and nematodes. Although Wolbachia DNA has been detected in ticks, its presence is generally associated with parasitism by insects. To determine whether or not Wolbachia can infect and grow in tick cells, cell lines from three tick species, Ixodes scapularis, Ixodes ricinus and Rhipicephalus microplus, were inoculated with Wolbachia strains wStri and wAlbB isolated from mosquito cell lines. Homogenates prepared from fleas collected from cats in Malaysia were inoculated into an I. scapularis cell line. Bacterial growth and identity were monitored by microscopy and PCR amplification and sequencing of fragments of Wolbachia genes. The wStri strain infected Ixodes spp. cells and was maintained through 29 passages. The wAlbB strain successfully infected Ixodes spp. and R. microplus cells and was maintained through 2–5 passages. A novel strain of Wolbachia belonging to the supergroup F, designated wCfeF, was isolated in I. scapularis cells from a pool of Ctenocephalides sp. cat fleas and maintained in vitro through two passages over nine months. This is the first confirmed isolation of a Wolbachia strain from a flea and the first isolation of any Wolbachia strain outside the “pandemic” A and B supergroups. The study demonstrates that tick cells can host multiple Wolbachia strains, and can be added to panels of insect cell lines to improve success rates in isolation of field strains of Wolbachia.

KW - Ctenocephalides

KW - Flea

KW - In vitro culture

KW - Malaysia

KW - Phylogeny

KW - Tick cell line

KW - Wolbachia

UR - http://www.scopus.com/inward/record.url?scp=85087438868&partnerID=8YFLogxK

U2 - 10.3390/microorganisms8070988

DO - 10.3390/microorganisms8070988

M3 - Article

AN - SCOPUS:85087438868

VL - 8

SP - 1

EP - 19

JO - Microorganisms

JF - Microorganisms

SN - 2076-2607

IS - 7

M1 - 988

ER -