Replication Kinetics of <i>Rickettsia raoultii</i> in Tick Cell Lines

Husin, Nurul Aini, Khoo, Jing Jing ORCID: 0000-0003-1285-6052, Zulkifli, Mulya Mustika Sari, Bell-Sakyi, Lesley ORCID: 0000-0002-7305-0477 and AbuBakar, Sazaly
(2021) Replication Kinetics of <i>Rickettsia raoultii</i> in Tick Cell Lines. MICROORGANISMS, 9 (7). 1370-.

Access the full-text of this item by clicking on the Open Access link.


Rickettsia raoultii is one of the causative agents of tick-borne lymphadenopathy in humans. This bacterium was previously isolated and propagated in tick cell lines; however, the growth characteristics have not been investigated. Here, we present the replication kinetics of R. raoultii in cell lines derived from different tick genera (BME/CTVM23, RSE/PILS35, and IDE8). Tick cell cultures were infected in duplicate with cryopreserved R. raoultii prepared from homologous cell lines. By 12-14 days post infection, 100% of the cells were infected, as visualized in Giemsa-stained cytocentrifuge smears. R. raoultii growth curves, determined by rickettsiae-specific gltA qPCR, exhibited lag, exponential, stationary and death phases. Exponential phases of 4-12 days and generation times of 0.9-2.6 days were observed. R. raoultii in BME/CTVM23 and RSE/PILS35 cultures showed, respectively, 39.5- and 37.1-fold increases compared to the inoculum. In contrast, multiplication of R. raoultii in the IDE8 cultures was 110.1-fold greater than the inoculum with a 7-day stationary phase. These findings suggest variation in the growth kinetics of R. raoultii in the different tick cell lines tested, amongst which IDE8 cells could tolerate the highest levels of R. raoultii replication. Further studies of R. raoultii are needed for a better understanding of its persistence within tick populations.

Item Type: Article
Uncontrolled Keywords: vector-borne disease, Rickettsia raoultii, infectious disease, tick cell line
Divisions: Faculty of Health and Life Sciences
Faculty of Health and Life Sciences > Institute of Infection, Veterinary and Ecological Sciences
Depositing User: Symplectic Admin
Date Deposited: 07 Oct 2021 10:36
Last Modified: 19 Oct 2023 08:58
DOI: 10.3390/microorganisms9071370
Open Access URL:
Related URLs: