Chlamydia pneumoniae

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Diagnosis of Chlamydia pneumoniae

Pekka Saikku

Culture of clinical samples has been a disappointment. In cases verified by serology, the sensitivity of isolation has been about 50% [11, 12, 13, 14, 15, 16]. There could be several reasons for this result. The ideal cell line for C. pneumoniae isolation may not have been found. Circulating strains may vary considerably in their ability to grow in cell cultures, and serologic findings can depend on the method used and the population studied. As a rule, in primary isolations, only a few inclusions are found. There is a possibility that only a few C. pneumoniae elementary bodies (EBs) in the sample are able to induce an inclusion. Another possible explanation is that the true number of infecting EBs is initially low, leading to the small amount of C. pneumoniae organisms in throat epithelium samples collected by swabbing. This latter assumption is supported by the low sensitivity of other diagnostic methods based on the direct demonstration of the organism or its components in throat swabs. Nasopharyngeal swabs have been recommended in some studies [5] but others have not found them to be of any advantage [17] Pretreatment of samples has been recommended [18]. The principal multiplication site of C. pneumoniae can be other than the superficial epithelium of the respiratory tract. When the pathogen invades deeper tissues, obtaining a proper sample can be more difficult. Since cough is usually non-productive, sputum samples are often difficult to obtain and thus induced sputa or bronchoalveolar lavages (BALs) are needed.

Bron: Sciencedirect, lees meer

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Evidence that Human Chlamydia pneumoniae Was Zoonotically Acquired

G. S. A. Myers, S. A. Mathews, M. Eppinger, C. Mitchell, K. K. O'Brien, O. R. White, F. Benahmed, R. C. Brunham, T. D. Read, J. Ravel, P. M. Bavoil, P. Timms

Bron: Journal of Bacteriology, lees meer

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The High Prevalence and Diversity of Chlamydiales DNA within Ixodes ricinus Ticks Suggest a Role for Ticks as Reservoirs and Vectors of Chlamydia-Related Bacteria

Ludovic Pilloux, Sébastien Aeby, [...], and Gilbert Greub

ABSTRACT

The Chlamydiales order is composed of nine families of strictly intracellular bacteria. Among them, Chlamydia trachomatis, C. pneumoniae, and C. psittaci are established human pathogens, whereas Waddlia chondrophila and Parachlamydia acanthamoebae have emerged as new pathogens in humans. However, despite their medical importance, their biodiversity and ecology remain to be studied. Even if arthropods and, particularly, ticks are well known to be vectors of numerous infectious agents such as viruses and bacteria, virtually nothing is known about ticks and chlamydia. This study investigated the prevalence of Chlamydiae in ticks. Specifically, 62,889 Ixodes ricinus ticks, consolidated into 8,534 pools, were sampled in 172 collection sites throughout Switzerland and were investigated using pan-Chlamydiales quantitative PCR (qPCR) for the presence of Chlamydiales DNA. Among the pools, 543 (6.4%) gave positive results and the estimated prevalence in individual ticks was 0.89%. Among those pools with positive results, we obtained 16S rRNA sequences for 359 samples, allowing classification of Chlamydiales DNA at the family level. A high level of biodiversity was observed, since six of the nine families belonging to the Chlamydiales order were detected. Those most common were Parachlamydiaceae (33.1%) and Rhabdochlamydiaceae (29.2%).“Unclassified Chlamydiales” (31.8%) were also often detected. Thanks to the huge amount of Chlamydiales DNA recovered from ticks, this report opens up new perspectives on further work focusing on whole-genome sequencing to increase our knowledge about Chlamydiales biodiversity. This report of an epidemiological study also demonstrates the presence of Chlamydia-related bacteria within Ixodes ricinus ticks and suggests a role for ticks in the transmission of and as a reservoir for these emerging pathogenic Chlamydia-related bacteria.

Bron: NCBI, lees meer

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Chlamydia pneumoniae and cardiovascular diseases

Pekka Saikku

Bron: clinicalmicrobiologyantheinfection.com, lees
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345.full.pdf

Chronic Chlamydia pneumoniae infection and
asthma exacerbations in children

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Higher incidence of persistent chronic infection of Chlamydia pneumoniae among coronary artery disease patients in India is a cause of concern

Hem C Jha, Harsh Vardhan, Rishein Gupta, Rakesh Varma, Jagdish Prasad & Aruna Mitta

Abstract
Background
There is growing evidence that Chlamydia pneumoniae may be involved in the pathogenesis of atherosclerosis, as several studies have demonstrated the presence of the organism in atherosclerotic lesions. C. pneumoniae infections, which are especially persistent infections, have been difficult to diagnose either by serological methods or isolation of the organism from the tissue. Nucleic Acid Amplification tests (NAATs) has emerged as an important method for detecting C. pneumoniae. Inspite of high prevalence of C. pneumoniae specific antibodies in coronary heart disease patients, direct detection of C. pneumoniae in circulating blood of coronary artery disease (CAD) patients by sensitive nucleic acid amplification tests nested PCR (nPCR), multiplex PCR (mPCR) has not been carried out is required. Further correlation of the presence of C. pneumoniae in blood of CAD patients with C. pneumoniae specific IgA and IgG antibodies, which may indicative of the status of infection with the progression of atherosclerosis. This will help in order to prepare strategies for the antibiotic intervention to avoid the progression towards CAD.

Bron: bmcinfectdis.biomedcentral, lees meer