Chlamydia species as a cause of community-acquired pneumonia in Canada

Chlamydia pneumoniae has been implicated as a cause of community-acquired pneumonia (CAP) in several studies. However, there has been no comprehensive study of the role of Chlamydia species (C. pneumoniae, C. psittaci (avian and feline strains) and C. pecorum) as a cause of CAP. The aim of the present study was to determine the role of C. pneumoniae, C. psittaci and C. pecorum as causes of CAP. A prospective cohort observational study of CAP was conducted at 15 teaching centres in eight Canadian provinces between January 1996-October 1997. Acute (n=539) and convalescent (n=272) serum samples were obtained for determination of antibody titres to C. pneumoniae, C. psittaci, C. pecorum, C. trachomatis, Mycoplasma pneumoniae, Legionella pneumophila serogroups I-VI, Streptococcus pneumoniae and various respiratory viruses. Twelve of 539 (2.2%) patients had acute C. pneumoniae pneumonia and an additional 32 (5.9%) had possible acute infection. C. pneumoniae was the sole pathogen in 16 of 42 (38.1%) of these patients. The most common copathogens were S. pneumoniae, respiratory syncytial virus and influenza virus type A. C. pneumoniae pneumonia patients were older and more likely to show congestive heart failure compared to bacteraemic S. pneumoniae patients. The latter had a lower mean diastolic blood pressure, a higher white blood cell count and a lower arterial carbon dioxide tension. Two patients had antibody titres suggestive of recent infection with the feline strain of C. psittaci. Although numerically Chlamydia pneumoniae is an important cause of community-acquired pneumonia, no distinctive clinical features associated with this pathogen were detected in the present study. Feline Chlamydia psittaci may cause a few cases of community-acquired pneumonia. Avian Chlamydia psittaci should be considered only if there is a compatible epidemiological history.

Lysosomes and the "toxicity" of rickettsiales. II. Non-cytocidal interactions of egg-grown C. psittaci 6BC and in vitro macrophages

During the infection of cultured mouse peritoneal phagocytes with egg-grown C. psittaci 6BC strain, lysosomes retained their integrity and host cells were not damaged. Infected monocytes showed greater ability than uninfected monocytes to spread and transform into giant cells containing enlarged nuclei and masses of cytoplasm with clear cytoplasmic vacuoles. Chlamydial particles were released from the cytoplasm of infected phagocytes by pseudopodia-like extrusions. These events were in marked contrast to the effect of L cell grown C. psittaci 6BC strain which caused early leakage of lysosomal acid phosphatase into the cytoplasm of macrophages and induced a rapidly progressive irreversible cell damage (14).

The occurrence and pathology of chlamydiosis in the male reproductive tract of non-human mammals: A review

Organisms belonging to the Family Chlamydiaceae are responsible for a broad range of diseases in humans, livestock, companion animals and non-domestic species. Infection of the reproductive organs can cause a range of syndromes of which sub- and infertility are the most frequently observed clinical manifestations. While the gross and histological lesions associated with the isolation of Chlamydiaceae from the non-human female reproductive tract are well documented, little attention has been given to the pathological effects of this infection in the male genital system. As such, the occurrence and importance of Chlamydia-associated disease in male non-human mammalian species is less well documented. In order to improve our understanding of the significance of chlamydiosis in domestic, laboratory and wild animals, this review provides an up-to-date summary of Chlamydia-associated male reproductive pathology, whether that infection occurs naturally or experimentally. Although most lesions in males are described as incidental and of minor significance, results of recent studies suggest that infection with Chlamydiaceae can adversely impact male fertility and/or be instrumental in disease transmission. Although in humans, bulls and mice Chlamydia infection has been associated with morphological and functional abnormalities of the spermatozoa, this review will focus on the gross and histological findings linked to the colonisation of the genital system by this pathogen. Advances in our understanding of male reproductive chlamydiosis are necessary for diagnostic and therapeutic strategies, as well as epidemiological and conservation studies.

Detection of a novel genotype of Chlamydia buteonis in falcons from the Emirates

Chlamydiaceae are a family of obligate intracellular bacterial pathogens that affect both humans and animals. Recently, a new species named Chlamydia (C.) buteonis was isolated from hawks. In this study, we aimed to investigate the prevalence of Chlamydiaceae in 60 falcons that underwent a routine health check at a specialized clinic in Dubai, United Arab Emirates. Using real-time PCR, we analyzed cloacal and tracheal swabs from these birds and found that 39 of them tested positive for Chlamydiaceae. Subsequent real-time PCR assays specific for C. psittaci, C. abortus, C. avium, and C. gallinacea yielded negative results, while testing positive for C. buteonis. Analysis of ompA and MLST sequences indicated a highly conserved group of strains within this set of samples, but with sequences distinct from the C. buteonis RSHA reference strains and other C. buteonis strains isolated from hawks in the United States. Two strains were further isolated by cell culture and sequenced using whole-genome sequencing, confirming the clustering of these falcon strains within the C. buteonis species, but in a separate clade from the previously identified hawk strains. We also developed a SNP-based PCR-HRM assay to distinguish between these different genotypes. Overall, our findings suggest a high prevalence of C. buteonis in falcons in Dubai and highlight the importance of monitoring this pathogen in birds of prey.