Chlamydia-Like Organisms (CLOs) in Finnish Ixodes ricinus Ticks and Human Skin.

Kati Hokynar,Jaana Panelius,Veera Timonen,Annamari Ranki,Mirja Puolakkainen,Thomas Lilley,Eero J Vesterinen,Jani J Sormunen,Esa K Partio

doi:10.3390/microorganisms4030028

Kati Hokynar, Jaana Panelius + Show 7 more

Open Access

https://doi.org/10.3390/microorganisms4030028

Copy DOI

Abstract

Ticks carry several human pathogenic microbes including Borreliae and Flavivirus causing tick-born encephalitis. Ticks can also carry DNA of Chlamydia-like organisms (CLOs). The purpose of this study was to investigate the occurrence of CLOs in ticks and skin biopsies taken from individuals with suspected tick bite. DNA from CLOs was detected by pan-Chlamydiales-PCR in 40% of adult ticks from southwestern Finland. The estimated minimal infection rate for nymphs and larvae (studied in pools) was 6% and 2%, respectively. For the first time, we show CLO DNA also in human skin as 68% of all skin biopsies studied contained CLO DNA as determined through pan-Chlamydiales-PCR. Sequence analyses based on the 16S rRNA gene fragment indicated that the sequences detected in ticks were heterogeneous, representing various CLO families; whereas the majority of the sequences from human skin remained “unclassified Chlamydiales” and might represent a new family-level lineage. CLO sequences detected in four skin biopsies were most closely related to “uncultured Chlamydial bacterium clones from Ixodes ricinus ticks” and two of them were very similar to CLO sequences from Finnish ticks. These results suggest that CLO DNA is present in human skin; ticks carry CLOs and could potentially transmit CLOs to humans.

Highlights

A total of nine families have so far been recognised as members of the order Chlamydiales [1,2]
326 DNA samples extracted from individual ticks and pooled ticks were analysed by Pan-Chlamydiales PCR targeting the 16S rRNA gene
Our study investigated the presence and diversity of Chlamydia-like organisms (CLO) DNA in ticks and in human skin with pan-Chlamydiales-PCR and sequence analysis of the PCR product

Summary

Introduction

A total of nine families have so far been recognised as members of the order Chlamydiales [1,2]. The most widely studied is the Chlamydiaceae-family that includes the well-known human pathogens Chlamydia trachomatis and C. pneumoniae, as well as several animal pathogens (some with zoonotic potential). Members of the remaining eight families (Clavichlamydiaceae, Criblamydiaceae, Piscichlamydiaceae, Parachlamydiaceae, Rhabdochlamydiaceae, Simkaniaceae, Waddliaceae, and Parilichlamydiaceae) are called Chlamydia-like organisms (CLOs). They share intracellular lifestyle, biphasic developmental cycle and a large core gene set (the “Pan-Genome of the Chlamydiae”) with the genus Chlamydia [3]. The role of CLOs as human pathogens is currently being explored: Recent publications have reported association between Waddlia chondrophila and tubal factor infertility [11], adverse pregnancy outcome [12] and lower respiratory tract infections [13]; Simkania negevensis and Rhabdochlamydia spp. may be associated with respiratory infections [14,15,16], and Parachlamydia acanthamoebae with pneumonia [17,18,19]

Objectives

Methods

Results

Conclusion