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-.

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<i>Rickettsia raoultii</i> 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 <i>R. raoultii</i> in cell lines derived from different tick genera (BME/CTVM23, RSE/PILS35, and IDE8). Tick cell cultures were infected in duplicate with cryopreserved <i>R. raoultii</i> prepared from homologous cell lines. By 12-14 days post infection, 100% of the cells were infected, as visualized in Giemsa-stained cytocentrifuge smears. <i>R. raoultii</i> 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. <i>R. raoultii</i> in BME/CTVM23 and RSE/PILS35 cultures showed, respectively, 39.5- and 37.1-fold increases compared to the inoculum. In contrast, multiplication of <i>R. raoultii</i> 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 <i>R. raoultii</i> in the different tick cell lines tested, amongst which IDE8 cells could tolerate the highest levels of <i>R. raoultii</i> replication. Further studies of <i>R. raoultii</i> 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: 26 Jan 2024 01:07
DOI: 10.3390/microorganisms9071370
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