New evidence for domesticated animals as reservoirs of Chlamydia-associated community-acquired pneumonia

Borel, Nicole; Heijne, Marloes; Pannekoek, Yvonne

doi:10.1016/j.cmi.2018.10.015

Cited by 10 publications

(6 citation statements)

References 13 publications

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“…As we pointed out previously [ 23 ], there are increasing doubts whether only these species play a role in human mucosal disease. In recent years, several new types of Chlamydia have been found in human samples from volunteers without disease symptoms [ 35 , 36 ] or patients with respiratory diseases [ 37 , 38 , 39 ]. In addition, Candidatus Renichlamydia lutjani was found in a patient with acute pneumonia, and this infection was recognized by ELISA specific to C. pneumoniae [ 23 ].…”

Section: Discussionmentioning

confidence: 99%

Are ELISA and PCR Discrepancies in the Identification of Chlamydia pneumoniae Caused by the Presence of “Chlamydia-Related Bacteria”?

Smolejová

Krčmáriková²,

Cihová

et al. 2023

Microorganisms

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Chlamydia are Gram-negative, intracellular pathogens colonizing the epithelial mucosa. They cause primarily atypical pneumonia and have recently been associated with chronic diseases. Diagnostics rely almost exclusively on serological methods; PCR tests are used rarely because in patients with positive ELISA, it is nearly impossible to identify chlamydial DNA. To understand this issue, we elaborated a reliable and sensitive nested PCR method (panNPCR) for identifying all Chlamydiales species, not only in sputa, but also in clotted blood. Sequencing of the PCR product revealed that 41% of positive sputa samples and 66% of positive blood samples were not infected by Chlamydia but with “Chlamydia-related bacteria” such as Rhabdochlamydia sp., Parachlamydia sp., Protochlamydia sp., Neochlamydia sp., Mesochlamydia elodeae and lacustris, Piscichlamydia salmonis, and Estrella lausannensis. Consequently, we propose that there might be more than four human pathogenic Chlamydia species. We did not find any clear correlation between increased levels of antibodies and the presence of their DNA. Chlamydialles DNA was found in sputa samples from individuals positive for IgG or IgA but not in blood samples. Thus, elevated IgG and IgA levels are not reliable markers of chronic infection, and the presence of persistent forms should be proved by panNPCR. Apparently, the differences between ELISA and DNA amplification results have three main methodological reasons. The first one is the threshold occurrence of chlamydial genetic material in sputum and blood. The second one is the fact that a significant part of the samples can have DNA with sequences different from those of other species of the order Chlamydiales. The third one is the high background characteristic for ELISA, the absence of paired sera, and the vague interpretation of the gray zone.

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Section: Discussionmentioning

confidence: 99%

Are ELISA and PCR Discrepancies in the Identification of Chlamydia pneumoniae Caused by the Presence of “Chlamydia-Related Bacteria”?

Smolejová

Krčmáriková²,

Cihová

et al. 2023

Microorganisms

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“…Surprisingly, sequences from three samples did not belong to either of the four assayed species. In recent years, several new types of Chlamydia have been found in human samples from volunteers without disease symptoms [ 63 , 64 ] or patients with respiratory diseases [ 47 , 65 , 66 ]. Sample 1080 contained DNA related to Ca.…”

Section: Discussionmentioning

confidence: 99%

Reliable and Sensitive Nested PCR for the Detection of Chlamydia in Sputum

2021

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Chlamydia are Gram-negative, intracellular pathogens colonizing epithelial mucosa. They cause primarily atypical pneumonia and have recently been associated with chronic diseases. Diagnostics relies almost exclusively on serological methods; PCR tests are used rarely because in patients with positive ELISA, it is nearly impossible to identify chlamydial DNA. This paradox is associated with DNA degradation in sputum samples, low abundance, and low sensitivity of PCR systems. In a newly designed and validated “nested” PCR (NPCR) assay, it was possible to amplify DNA of Chlamydia known to infect humans in 31% samples. The reliability of the assay was confirmed by DNA sequencing, and all PCR products belonged exclusively to the Chlamydiales, mainly recognized as Chlamydia pneumoniae. Three samples were related to Ca. Rhabdochlamydia porcellionis and Ca. Renichlamydia lutjani, which infect arthropods. In one case, samples were taken from sick individual, indicating the potential as a human pathogen.

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“…The sequencing result was consistent with the C. pneumoniae -positive PCR data strengthening the plausibility of the results obtained with PanChlamydiales-PCR and sequencing. Among specimens collected during this outbreak, neither Chlamydia psittaci nor Chlamydia caviae , which recently have been reported to cause pneumonia in humans, i.e., due to exposure to ill guinea pigs, were seen [27,28,29]. Interestingly, however, two of the sequences that, by the scheme used, remained as “unclassified”, bunched together in the phylogenetic analysis (sequences V42 and V49; Figure 1) and might represent a novel type of Chlamydia-related bacteria.…”

Section: Discussionmentioning

confidence: 99%

“…Even today in as many as 50% of the cases the microbe causing pneumonia remains unidentified. For example, as pointed out by Polkinghorne et al [27], there is an increasing number of reports on CAP cases caused by bacteria belonging in the genus Chlamydia that thus far have been considered solely animal pathogens, i.e., Chlamydia caviae . In addition to members of chlamydiaceae, a wide range of the newly detected chlamydia-related bacteria have been associated with respiratory symptoms including pneumonia.…”

Section: Discussionmentioning

confidence: 99%

Parachlamydia acanthamoebae Detected during a Pneumonia Outbreak in Southeastern Finland, in 2017–2018

et al. 2019

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Community-acquired pneumonia (CAP) is a common disease responsible for significant morbidity and mortality. However, the definite etiology of CAP often remains unresolved, suggesting that unknown agents of pneumonia remain to be identified. The recently discovered members of the order Chlamydiales, Chlamydia-related bacteria (CRB), are considered as possible emerging agents of CAP. Parachlamydia acanthamoebae is the most studied candidate. It survives and replicates inside free-living amoeba, which it might potentially use as a vehicle to infect animals and humans. A Mycoplasma pneumoniae outbreak was observed in Kymenlaakso region in Southeastern Finland during August 2017–January 2018. We determined the occurrence of Chlamydiales bacteria and their natural host, free-living amoeba in respiratory specimens collected during this outbreak with molecular methods. Altogether, 22/278 (7.9%) of the samples contained Chlamydiales DNA. By sequence analysis, majority of the CRBs detected were members of the Parachlamydiaceae family. Amoebal DNA was not detected within the sample material. Our study further proposes that Parachlamydiaceae could be a potential agent causing atypical CAP in children and adolescents.

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New evidence for domesticated animals as reservoirs of Chlamydia-associated community-acquired pneumonia

Cited by 10 publications

References 13 publications

Are ELISA and PCR Discrepancies in the Identification of Chlamydia pneumoniae Caused by the Presence of “Chlamydia-Related Bacteria”?

Are ELISA and PCR Discrepancies in the Identification of Chlamydia pneumoniae Caused by the Presence of “Chlamydia-Related Bacteria”?

Reliable and Sensitive Nested PCR for the Detection of Chlamydia in Sputum

Parachlamydia acanthamoebae Detected during a Pneumonia Outbreak in Southeastern Finland, in 2017–2018

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