Detection of Chlamydia pneumoniae in a collection of captive snakes and response to treatment with marbofloxacin

An outbreak of systemic chlamydiosis in farmed American alligators (Alligator mississippiensis)

Chlamydia spp are reported to causes systemic disease in a variety of hosts worldwide including few reports in crocodilians. Disease presentations vary from asymptomatic to fulminant disease, some of which are zoonotic. The aim of this study was to describe the pathological, immunohistochemical, and molecular findings associated with the occurrence of a previously unreported Chlamydia sp infection causing a major mortality event in farmed American alligators (Alligator mississippiensis). The outbreak presented with sudden death in juvenile alligators mainly associated with necrotizing hepatitis and myocarditis, followed by the occurrence of conjunctivitis after the initial high mortality event. The widespread inflammatory lesions in multiple organs correlated with intralesional chlamydial organisms identified via immunohistochemistry and confirmed by 23S rRNA-specific real-time quantitative polymerase chain reaction (qPCR) for Chlamydiaceae bacteria. By sequencing and phylogenetic analysis of the OmpA gene, this uncultured Chlamydia sp grouped closely with Chlamydia poikilothermis recently described in snakes. This study highlights the significance of such outbreaks in farmed populations. Enhanced epidemiological monitoring is needed to gain further insight into the biology of Chlamydia sp in alligators, disease dynamics, risk factors, and role of carrier animals.

DETECTION OF MYCOPLASMA AND CHLAMYDIA IN PYTHONS WITH AND WITHOUT SERPENTOVIRUS INFECTION

Serpentoviruses (order Nidovirales) are an important cause of respiratory disease in snakes. Although transmission studies have shown that serpentoviruses can cause respiratory disease in pythons, the possible role of additional potential pathogens is not yet understood. Very little information is available on the role of mycoplasma and chlamydia infections in disease in pythons. Diagnostic samples from 271 pythons of different genera submitted to a laboratory for detection of serpentoviruses were also screened for mycoplasma and chlamydia infections by PCR. Most of the samples were oral swabs. Almost 30% of the samples were positive for serpentoviruses, and mycoplasmas were detected in more than 60% of the pythons. The occurrence of these two pathogens correlated significantly (P < 0.001). Additionally, about 3% of the snakes tested positive for Chlamydia. This study found a high prevalence of mycoplasmas in the tested pythons and a correlation between infections with these bacteria and serpentoviruses in python samples submitted for diagnostic testing. Because the role mycoplasmas play in respiratory diseases of snakes is still largely unknown, further investigations are necessary to evaluate the role of mixed infections in disease.

Chlamydiae - What's New?

This paper provides an overview of the current knowledge of chlamydiae. These intracellular microorganisms belonging to the Chlamydiaceae family are widely distributed throughout the world. Constant development of culture-independent approaches for characterisation of microbial genomes enables new discoveries in the field of Chlamydia. The number of new taxa is continuously increasing as well as the range of hosts. New species and genotypes are constantly being discovered, particularly new avian and reptilian agents, which are discussed in this article. Interestingly, wild animals are the main hosts for new Chlamydia species including different species of bird, turtle and snake. The availability of next-generation sequencing opens up a new prospect for research and leads to deeper knowledge of these interesting microorganisms about which much is still to discover.

Chronic wasting associated with Chlamydia pneumoniae in three ex situ breeding facilities for tropical frogs

A number of different Chlamydia spp. have been detected in the class Amphibia with C. pneumoniae being the predominant species involved. Chlamydiae have been linked to mass mortality events, thereby representing significant pathogens that deserve attention with respect to worldwide amphibian decline. We here present six cases of chlamydiosis and asymptomatic chlamydial infections in different frog species from three ex situ amphibian conservation facilities. Clinical signs predominantly characterised by regurgitation, chronic wasting, lethargy and suspended breeding were associated with C. pneumoniae infection. Despite various treatment regimens, it was not possible to clear infections. However, intra vitam diagnostics succeeded from skin, faeces and urine for the first time.

Global Prevalence of Chlamydial Infections in Reptiles: A Systematic Review and Meta-Analysis

Background and Objectives: Chlamydia spp. are potential zoonotic pathogens that can infect a wide range of animal hosts. In reptiles, Chlamydia can cause hepatitis, pneumonitis, and conjunctivitis and it can cause high mortality in young animals. The objectives of this study were to estimate the pooled prevalence of chlamydial infections in reptiles and to assess the trend of these infections over time. Materials and Methods: The study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies were retrieved from PubMed, Scopus, and Web of Science. The retrieved studies were screened for eligibility. Then, important data were extracted from the included studies. A random effects model was used for all analyses. Subgroup analysis was used to assess heterogeneity for orders of reptiles, continents where the studies were conducted, and types of specimens. Cumulative meta-analysis and meta-regression were used to determine the trend of the prevalence over time. The quality of each included study was evaluated. Results: Of 106 studies (with a total of 2607 samples), 20 met the inclusion criteria and were included in the meta-analysis. The pooled prevalence of chlamydial infections in reptiles was 23.5% (95% confidence interval [CI]: 15.4-34.0). The trend of chlamydial infections increased from 1990 to 2008; thereafter, it was almost stable at slightly over 20%. The most commonly reported Chlamydia spp. were Chlamydia psittaci, Chlamydia pneumoniae, Chlamydia pecorum, and Chlamydia caviae. Among reptiles, the prevalence of chlamydial infections was highest in crocodiles (57.3% [95% CI: 32.5-78.9]). Among continents, the prevalence of chlamydial infections was highest in Australia (68.6% [95% CI: 36.8-89.1]). Conclusions: Based on the included studies, the prevalence of chlamydial infections in reptiles was high, especially in crocodiles. Because C. psittaci and C. pneumoniae are commonly found in reptiles and are well-known zoonotic pathogens, they should be of concern for human health.

A cluster of Chlamydia serpentis cases in captive snakes

Following the occurrence of sudden death cases in a zoo reptile collection, histological analyses conducted on tissues from two common adders suggested an infection due to Chlamydia. The survey was extended to 22 individual snakes from the same collection and a PCR analysis targeting a conserved gene in Chlamydiaceae revealed bacterial shedding in six of them. The infection resolved spontaneously in one snake whereas another one succumbed one month later. The antibiotic treatment administered (marbofloxacin) to the remaining four PCR positive animals stopped the mortalities and the shedding. Analysis of the 16S and 23S ribosomal gene sequences identified C. serpentis, a recently described novel chlamydial species in snakes. A PCR tool for a quick and specific identification of this new chlamydial species was developed in this study.

Novel Chlamydia species isolated from snakes are temperature-sensitive and exhibit decreased susceptibility to azithromycin

Chlamydia species have recently been recognized as emerging pathogens in snakes. However, isolation of novel snake chlamydiae is critical and their growth characteristics are largely unknown. In this study, two novel chlamydial species are described: Chlamydia serpentis and Chlamydia poikilothermis, isolated after attempts on 23 cloacal and choanal swabs from 18 PCR-positive captive snakes originating from different Swiss snake collections. Isolation success, growth curve and infectivity rates over a 48-hour time period were dependent on temperature (37 °C for C. serpentis, 28 °C for C. poikilothermis). C. serpentis and C. poikilothermis were sensitive to tetracycline and moxifloxacin during evaluation by in vitro antibiotic susceptibility assay but intermediate to resistant (2–4 μg/ml) to azithromycin. Whole genome sequencing of the isolates provided proof of the novel species status, and gives insights into the evolution of these branches of genus Chlamydia.

A Review on Chlamydial Diseases in Animals: Still a Challenge for Pathologists?

Chlamydiae have a worldwide distribution causing a wide range of diseases in human hosts, livestock, and companion animals as well as in wildlife and exotic species. Moreover, they can persist in their hosts as asymptomatic infections for extended periods of time. The introduction of molecular techniques has revolutionized the Chlamydia field by expanding the host range of known chlamydial species but also by discovering new species and even new families of bacteria in the broader order Chlamydiales. The wide range of hosts, diseases, and tissues affected by chlamydiae complicate the diagnosis such that standard diagnostic approaches for these bacteria are rare. Bacteria of the Chlamydiales order are small and their inclusions are difficult to detect by standard microscopy. With the exception of avian and ovine chlamydiosis, macroscopic and/or histologic changes might not be pathognomic or indicative for a chlamydial infection or even not present at all. Moreover, detection of chlamydial DNA in specimens in the absence of other methods or related pathological lesions questions the significance of such findings. The pathogenic potential of the majority of recently identified Chlamydia-related bacteria remains largely unknown and awaits investigation through experimental or natural infection models including histomorphological characterization of associated lesions. This review aims to summarize the historical background and the most important developments in the field of animal chlamydial research in the past 5 years with a special focus on pathology. It will summarize the current nomenclature, present critical thoughts about diagnostics, and give an update on chlamydial infections in domesticated animals such as livestock, companion animals and birds, as well as free-ranging and captive wild animals such as reptiles, fish, and marsupials.

Culture-independent metagenomics supports discovery of uncultivable bacteria within the genus Chlamydia

Advances in culture-independent methods have meant that we can more readily detect and diagnose emerging infectious disease threats in humans and animals. Metagenomics is fast becoming a popular tool for detection and characterisation of novel bacterial pathogens in their environment, and is particularly useful for obligate intracellular bacteria such as Chlamydiae that require labour-intensive culturing. We have used this tool to investigate the microbial metagenomes of Chlamydia-positive cloaca and choana samples from snakes. The microbial complexity within these anatomical sites meant that despite previous detection of chlamydial 16S rRNA sequences by single-gene broad-range PCR, only a chlamydial plasmid could be detected in all samples, and a chlamydial chromosome in one sample. Comparative genomic analysis of the latter revealed it represented a novel taxon, Ca. Chlamydia corallus, with genetic differences in regards to purine and pyrimidine metabolism. Utilising statistical methods to relate plasmid phylogeny to the phylogeny of chromosomal sequences showed that the samples also contain additional novel strains of Ca. C. corallus and two putative novel species in the genus Chlamydia. This study highlights the value of metagenomics methods for rapid novel bacterial discovery and the insights it can provide into the biology of uncultivable intracellular bacteria such as Chlamydiae.

Domestic reptiles as source of zoonotic bacteria: A mini review

Captive reptiles, always more often present in domestic environment as pets, may harbor and excrete a large variety of zoonotic pathogens. Among them, Salmonella is the most well-known agent, whereas there are very scant data about infections by mycobacteria, chlamydiae and leptospirae in cold-blooded animals. However, the investigations that found antibody reactions and/or the bacteria in samples collected from free-ranging and captive reptiles show that herpetofauna may be involved in the epidemiology of these infections. The present review reports the updated knowledge about salmonellosis, mycobacteriosis, chlamydiosis and leptospirosis in reptiles and underlines the risk of infection to which people, mainly children, are exposed.