Culture Isolate of Rickettsia felis from a Tick

Abstract

Although the cat flea, Ctenocephalides felis, has been identified as the primary vector of Rickettsia felis, additional flea, tick, mite, and louse species have also been associated with this bacterium by molecular means; however, the role of these arthropods in the transmission of R. felis has not been clarified. Here, we succeeded in culture isolation of R. felis from a host-seeking castor bean tick, Ixodes ricinus, the most common tick in Slovakia. The bacterial isolation was performed on XTC-2 cells at 28 °C using the shell-vial technique. An evaluation of the growth properties was performed for both the XTC-2 and Vero cell lines. We observed R. felis in the infected host cells microscopically by Gimenez staining and immunofluorescence assay. The R. felis isolate was purified by gradient ultracentrifugation and visualized by electron microscopy. Fragments of the genes gltA, ompA, ompB, htrA, rpoB, sca4, rffE, and rrs were amplified and compared with the corresponding sequences of the type strain URRWXCal2 and other R. felis culture -isolated strains. We did not detect any nucleotide polymorphisms; however, plasmid pRFδ, characteristic of the standard strain, was absent in our isolate. Herein, we describe the first successful isolation and characterization of a tick-derived R. felis strain “Danube”, obtained from an I. ricinus nymph.

Mild Infections with Multiple Spotted Fever Grouped Rickettsia Species among Forest Rangers with Tick Bites

“…The discovery of one victim with an R. felis infection in our survey corroborates previous reports on R. felis in Chinese populations [14]. Although R. felis was recently isolated from an I. ricinus nymph tick [19], the role of ticks and other vectors in transmitting the agent needs to be determined. CRT, a member of the ancestral R. canadensis group [17], was first described from I. persulcatus ticks collected in the Russian Urals and Siberia in 2003 [20].…”

Actualización Sobre Aspectos Epidemiológicos De La Rickettsiosis en El Trópico De México

“…Las especies patógenas de Rickettsia tienen limitada viabilidad fuera del organismo del hospedero mamífero o el reservorio artrópodo. No crecen en los medios habituales de cultivo, por lo que es necesario inocularlas experimentalmente en animales de laboratorio (roedores o cobayos), huevos embrionados, o propagarlas en líneas celulares como Vero, HEL, L-929, o derivadas de artrópodos (Kamath et al, 2020;Danchenko et al, 2022). Poseen diferentes proteínas mayores de superficie, entre las que destacan la OmpA, presente exclusivamente en los miembros del grupo de las fiebres manchadas (SFG por sus siglas en inglés) y la OmpB que se encuentra en todas las especies del género (Kamath et al, 2020).…”

Rickettsia Deregulates Genes Coding for the Neurotoxic Cell Response Pathways in Cerebrocortical Neurons In Vitro

“…Rickettsiae were propagated in confluent monolayers of the Vero cell line (Cercopithecus aethiops kidney cells, ATCC CCL-81), maintained in an RPMI 1640 medium (Lonza, Basel, Switzerland) supplemented with 2 mM L-glutamine (Lonza, Basel, Switzerland), 25 mM HEPES (Sigma-Aldrich, St. Louis, MO, USA), and 2.5% heat-inactivated fetal bovine serum (HyClone, Logan, UT, USA) at 34 • C in a humidified 5% CO 2 incubator. Rickettsiae were purified by a modified isopycnic density gradient centrifugation protocol described previously [28] and stored in an SPG buffer (0.218 M sucrose, 3.76 mM KH 2 PO 4 , 7.1 mM K 2 HPO 4 , and 4.9 mM potassium glutamate) at −80 • C for further experiments.…”