[Abortion in humans caused by Chlamydophila abortus (Chlamydia psittaci serovar 1)]

Clinical identification and microbiota analysis of Chlamydia psittaci- and Chlamydia abortus- pneumonia by metagenomic next-generation sequencing

Introduction

Recently, the incidence of chlamydial pneumonia caused by rare pathogens such as C. psittaci or C. abortus has shown a significant upward trend. The non-specific clinical manifestations and the limitations of traditional pathogen identification methods determine that chlamydial pneumonia is likely to be poorly diagnosed or even misdiagnosed, and may further result in delayed treatment or unnecessary antibiotic use. mNGS's non-preference and high sensitivity give us the opportunity to obtain more sensitive detection results than traditional methods for rare pathogens such as C. psittaci or C. abortus.

Methods

In the present study, we investigated both the pathogenic profile characteristics and the lower respiratory tract microbiota of pneumonia patients with different chlamydial infection patterns using mNGS.

Results

More co-infecting pathogens were found to be detectable in clinical samples from patients infected with C. psittaci compared to C. abortus, suggesting that patients infected with C. psittaci may have a higher risk of mixed infection, which in turn leads to more severe clinical symptoms and a longer disease course cycle. Further, we also used mNGS data to analyze for the first time the characteristic differences in the lower respiratory tract microbiota of patients with and without chlamydial pneumonia, the impact of the pattern of Chlamydia infection on the lower respiratory tract microbiota, and the clinical relevance of these characteristics. Significantly different profiles of lower respiratory tract microbiota and microecological diversity were found among different clinical subgroups, and in particular, mixed infections with C. psittaci and C. abortus resulted in lower lung microbiota diversity, suggesting that chlamydial infections shape the unique lung microbiota pathology, while mixed infections with different Chlamydia may have important effects on the composition and diversity of the lung microbiota.

Discussion

The present study provides possible evidences supporting the close correlation between chlamydial infection, altered microbial diversity in patients' lungs and clinical parameters associated with infection or inflammation in patients, which also provides a new research direction to better understand the pathogenic mechanisms of pulmonary infections caused by Chlamydia.

Extracorporeal Membrane Oxygenation in Severe Acute Respiratory Distress Syndrome Caused by Chlamydia abortus: A Case Report

Background

Pneumonia infected by Chlamydia abortus (C. abortus) is rare, especially complicated with severe acute respiratory distress syndrome (ARDS) and multiple organ dysfunction syndrome (MODS).

Case Presentation

We presented the clinical details of a 44-year-old male who was diagnosed with C. abortus pneumonia, which rapidly progressed and ultimately led to ARDS, sepsis and MODS. Although he was initially diagnosed with pneumonia upon admission, no pathogenic bacteria were detected in sputum by conventional tests. Empirical intravenous infusion of meropenem and moxifloxacin was administered, but unfortunately, his condition deteriorated rapidly, especially respiratory status. On Day 2 after extracorporeal membrane oxygenation (ECMO) initiation, metagenomic next-generation sequencing (mNGS) was performed on the patient's bronchoalveolar lavage fluid, which indicated an infection with C. abortus. The patient's antimicrobial therapy was adjusted to oral doxycycline (0.1g every 12h), intravenous azithromycin (0.5g every day), and imipenem and cilastatin sodium (1g every 6h). The patient's condition improved clinically and biologically. However, the patient was discharged due to financial reasons and unfortunately passed away eight hours later.

Conclusion

Infections with C. abortus can result in severe ARDS and serious visceral complications which necessitate prompt diagnosis and active intervention by clinicians. The case highlights the significance of mNGS as an essential diagnostic tool for uncommon pathogens. Tetracyclines, macrolides or their combinations are effective choices for treatment of C. abortus pneumonia. Further study is needed to explore the transmission routes of C. abortus pneumonia and establish precise guidelines for antibiotic treatment.

Metagenomic Next-Generation Sequencing Contributes to the Diagnosis of Pneumonia Caused by Chlamydia abortus in a Male Patient: Case Report and Literature Review

Background

Chlamydia abortus is generally considered as the main cause of ruminants abortion, but it rarely causes human infection resulting in abortion or pneumonia.

Case Presentation

We report a case of male patient with pneumonia caused by Chlamydia abortus. Results of next generation sequencing (NGS) in the bronchoalveolar lavage fluid (BALF) indicated Chlamydia abortus infection. The patient was treated with intravenous infusion of doxycycline. The clinical symptoms of this patient were ameliorated significantly, and all these improvement were indicated by laboratory parameters significantly. Shown as chest computed tomography (CT), most of the inflammation had been absorbed after doxycycline treatment.

Conclusion

Chlamydia abortus mainly infects ruminants and occasionally humans. NGS has its own advantages of rapidity, sensitivity and specificity in detecting Chlamydia abortus. Doxycycline exhibits a great therapeutic effect on pneumonia caused by Chlamydia abortus.

Seroprevalence of antibodies to Chlamydia abortus and risk factors in cattle from Villavicencio, Colombia

Chlamydia abortus is a Gram-negative obligate intracellular bacterium, responsible for abortions and reproductive problems. The disease has a high zoonotic potential and causes great economic losses in ruminant farmers. A cross-sectional study was carried out with 514 cattle from 24 farms of Villavicencio, Colombia. The blood samples were collected from each individual animal and analyzed by Indirect Elisa for immunoglobulin G (IgG) in blood serum (Idexx Chlamydiosis total Ab test). A serum was considered positive when the optical density (OD) of the sample was ≥30% of that of the positive control serum. Data on potential risk factors associated with the disease were collected through a questionnaire in each farm and analyzed. The individual and herd prevalence was estimated. A risk factors analysis was performed through univariate and multivariable using the software SPSS version 20. The animal level seroprevalence was found to be 47.1% and the herd 91.6%. The prevalence in cattle aged 0-1, 1-3 and >4 years was 23.8%; 31.4% and 51.4% respectively. The risk factors associated with the prevalence of disease were female sex (OR = 2.102 CI: 1.066-4.144), age older than 4 years (OR = 2.707 CI: 1.667-4.394), presence of canines on the farm (OR = 2.556 CI: 1.560-4.189) and retention of placenta (OR = 2.678 CI: 1.670-4.295). A high prevalence was identified, suggesting natural infection where the pathogen could be transmitted to humans at the animal-human interface.

Bloodstream infection and pneumonia caused by Chlamydia abortus infection in China: a case report

Background

Chlamydia abortus is generally considered to cause abortion, stillbirth, and gestational sepsis in pregnant women, but it’s rare in bloodstream infection and pneumonia.

Case presentation

We present details of a patient with bloodstream infection and pneumonia caused by Chlamydia abortus. Both blood next-generation sequencing (NGS) and sputum NGS indicate Chlamydia abortus infection. The patient received intravenous infusion of piperacillin sodium and tazobactam sodium (4.5 g/8 h) and moxifloxacin (0.4 g/d) and oral oseltamivir (75 mg/day). Within one month of follow-up, the patient's clinical symptoms were significantly improved, and all laboratory parameters showed no marked abnormality. However, chest computer tomography (CT) showed the inflammation wasn’t completely absorbed. And we are still following up.

Conclusions

Chlamydia abortus can cause pneumonia in humans. NGS has the particular advantage of quickly and accurately identifying the infection of such rare pathogens. Pneumonia is generally not life-threatening, and has a good prognosis with appropriate treatment. However, Chlamydia infection can lead to serious visceral complications which clinicians should pay attention to.

Efficacy of Two Chlamydia abortus Subcellular Vaccines in a Pregnant Ewe Challenge Model for Ovine Enzootic Abortion

Chlamydia abortus, the aetiological agent of enzootic abortion of ewes, is a major cause of reproductive loss in small ruminants worldwide, accounting for significant economic losses to the farming industry. Disease can be managed through the use of commercial inactivated or live whole organism-based vaccines, although both have limitations particularly in terms of efficacy, safety and disease-associated outbreaks. Here we report a comparison of two experimental vaccines (chlamydial outer membrane complex (COMC) and octyl glucoside (OG)-COMC) based on detergent extracted outer membrane preparations of C. abortus and delivered as prime-boost immunisations, with the commercial live vaccine Cevac^® Chlamydia in a pregnant sheep challenge model. No abortions occurred in either experimental vaccine group, while a single abortion occurred in the commercial vaccine group. Bacterial shedding, as a measure of potential risk of transmission of infection to naïve animals, was lowest in the COMC vaccinated group, with reductions of 87.5%, 86.4% and 74% observed for the COMC, OG-COMC and live commercial vaccine groups, respectively, compared to the unvaccinated challenge control group. The results show that the COMC vaccine performed the best and is a safer efficacious alternative to the commercial vaccines. However, to improve commercial viability, future studies should optimise the antigen dose and number of inoculations required.

Isolation and Identification of Chlamydia abortus from Aborted Ewes in Sulaimani Province, Northern Iraq

Abortion in small ruminants is a significant problem in Iraq and causes severe economic losses in sheep farms. Chlamydia abortus causes enzootic abortion in ewes and is associated with reproductive problems in sheep in Sulaimani province – Northern Iraq. During a lambing season in 2017, abortion was widespread among several sheep flocks in different regions of Sulaimani (Kalar, Said Sadiq, and Chamchamal), and C. abortus was one of the causes. Accordingly, we carried out this study to isolate and identify C. abortus in aborted ewes in these regions. We collected 30 samples of aborted fetuses from five herds in which abortions had been observed. The pathogen isolation was done by inoculation into embryonated chicken eggs and conventional PCR was used to identify C. abortus in clinical specimens. C. abortus was identified in one of the 30 aborted fetuses (3.33%) from the Kalar district, and all the remaining 29 samples (96.66%) were found positive to Brucella abortus. The gene ompA encoding the outer membrane protein of C. abortus was sequenced and got the accession number MK643153 in NCBI GenBank. The sequence was named C. abortus strain Sul/2017. Our isolate showed 99.79% homology with Sul/014 (accession No. KY399850) and differed from the latter by two amino acid substitutions at E115K and K259N. The topology of the phylogenetic tree based on the ompA gene showed that the isolate belongs to C. abortus and has a common ancestor with isolates of sheep in Iraq and Tunisia with accession numbers KY399850 and HQ62243, respectively.

New insights into chlamydial zoonoses

Chlamydiae are obligate intracellular bacterial pathogens of humans. Infections in animals are also widespread with some species, such as Chlamydia psittaci, long recognised as a serious threat to human health. Critical to the public health response of any zoonotic disease outbreaks is reliable and up-to-date information on the epidemiology of the target pathogen. Aided by advances in the use of quantitative PCR, molecular typing and culture-independent genomic studies, significant recent work has highlighted an expanded diversity and host range of chlamydial pathogens in animals. New and unexpected cases of chlamydial zoonoses have now been recently documented in Australia and elsewhere, emphasising the importance of multi-disciplinary ‘One Health' collaboration and the use of standardised methods to detect and characterise chlamydial pathogens in humans and animals.

Mini Review: Antimicrobial Control of Chlamydial Infections in Animals: Current Practices and Issues

Chlamydia are a genus of successful obligate intracellular pathogens spread across humans, wildlife, and domesticated animals. The most common species reported in livestock in this genus are Chlamydia abortus, Chlamydia psittaci, Chlamydia suis, and Chlamydia pecorum. Chlamydial infections trigger a series of inflammatory disease-related sequelae including arthritis, conjunctivitis, pneumonia, and abortion. Other bacteria in the phylum Chlamydiae have also been reported in livestock and wildlife but their impact on animal health is less clear. Control of chlamydial infections relies on the use of macrolides, fluoroquinolones, and tetracyclines. Tetracycline resistance (TET^R) reported for porcine C. suis strains in association with the use of tetracycline feed is a potentially significant concern given experimental evidence highlighting that the genetic elements inferring TET^R may be horizontally transferred to other chlamydial species. As documented in human Chlamydia trachomatis infections, relapse of infections, bacterial shedding post-antibiotic treatment, and disease progression despite chlamydial clearance in animals have also been reported. The identification of novel chlamydiae as well as new animal hosts for previously described chlamydial pathogens should place a renewed emphasis on basic in vivo studies to demonstrate the efficacy of existing and new antimicrobial treatment regimes. Building on recent reviews of antimicrobials limited to C. trachomatis and C. suis, this review will explore the use of antimicrobials, the evidence and factors that influence the treatment failure of chlamydial infections in animals and the future directions in the control of these important veterinary pathogens.

Antimicrobial Resistance in Chlamydiales, Rickettsia, Coxiella, and Other Intracellular Pathogens

This article will provide current insights into antimicrobial susceptibilities and resistance of an important group of bacterial pathogens that are not phylogenetically related but share lifestyle similarities in that they are generally considered to be obligate intracellular microbes. As such, there are shared challenges regarding methods for their detection and subsequent clinical management. Similarly, from the laboratory perspective, susceptibility testing is rarely undertaken, though molecular approaches might provide new insights. One should also bear in mind that the highly specialized microbial lifestyle restricts the opportunity for lateral gene transfer and, consequently, acquisition of resistance.

Poultry in Poland as Chlamydiaceae Carrier

Introduction

The study was conducted to investigate the prevalence and genetic diversity of Chlamydia spp. in poultry in Poland and estimate possible transmission to humans.

Material and Methods

Molecular diagnostic methods followed by sequencing and strain isolation were used on cloacal/faecal swabs collected from 182 apparently healthy poultry flocks including chickens, turkeys, ducks, and geese. Serum samples obtained from people exposed (study group) and non-exposed (control group) to birds were tested by complement fixation test to acquire data on Chlamydia spp. antibody level.

Results

Overall, 15.9% of the tested flocks were Chlamydiaceae-positive and three Chlamydia spp. were identified. Predominant chlamydial agent found was C. gallinacea occurring in 65.5% of all positive poultry flocks and in 73.0% of positive chicken flocks. The sequences from four chicken flocks were assigned to C. abortus, whereas C. psittaci was confirmed in one duck and one goose flock. The analysis of ompA variable domains revealed at least nine genetic variants of C. gallinacea. Chlamydial antibodies were detected in 19.2% of human serum samples in the study group in comparison with 10.8% in the controls.

Conclusion

The obtained results confirm that chlamydiae are common among chicken flocks in Poland with C. gallinacea as a dominant species. Moreover, the presence of C. abortus in chickens is reported here for the first time. Further investigation should focus on possible zoonotic transmission of C. gallinacea and C. abortus as well as potential pathogenic effects on birds’ health and poultry production.

In silico functional elucidation of uncharacterized proteins of Chlamydia abortus strain LLG

AIM

This study reports structural modeling, molecular dynamics profiling of hypothetical proteins in Chlamydia abortus genome database.

METHODOLOGY

The hypothetical protein sequences were extracted from C. abortus LLG Genome Database for functional elucidation using in silico methods.

RESULTS

Fifty-one proteins with their roles in defense, binding and transporting other biomolecules were unraveled. Forty-five proteins were found to be nonhomologous to proteins present in hosts infected by C. abortus. Of these, 31 proteins were related to virulence. The structural modeling of two proteins, first, WP_006344020.1 (phosphorylase) and second, WP_006344325.1 (chlamydial protease/proteasome-like activity factor) were accomplished. The conserved active sites necessary for the catalytic function were analyzed.

CONCLUSION

The finally concluded proteins are envisioned as possible targets for developing drugs to curtail chlamydial infections, however, and should be validated by molecular biological methods.

Chlamydia pecorum: fetal and placental lesions in sporadic caprine abortion

Chlamydial abortion in small ruminants is usually associated with Chlamydia abortus infection. Although Chlamydia pecorum has been detected in aborted ruminants and epidemiological data suggests that C. pecorum is abortigenic in these species, published descriptions of lesions in fetuses are lacking. This work describes fetoplacental lesions in a caprine abortion with C. pecorum infection, and further supports the abortigenic role of C. pecorum in ruminants. A 16-month-old Boer goat aborted twin fetuses at ~130 days of gestation. Both fetuses (A and B) and the placenta of fetus A were submitted for postmortem examination and diagnostic workup. At autopsy, the fetuses had moderate anasarca, intermuscular edema in the hindquarters (A), and brachygnathia and palatoschisis (B). In the placenta, the cotyledons were covered by yellow fibrinosuppurative exudate that extended into the adjacent intercotyledonary areas. Histologically, there was severe suppurative and necrotizing placentitis with vasculitis (arteriolitis) and thrombosis, multifocal lymphohistiocytic and neutrophilic hepatitis (A), and fibrinosuppurative enteritis in both fetuses. Chlamydia antigen was detected in the placenta by the direct fluorescent antibody test and in fetal intestines by immunohistochemistry. Nested polymerase chain reaction of DNA extracted from formalin-fixed, paraffin-embedded sections of placenta and intestine amplified 400 bp of the Chlamydia 16S rRNA gene that was sequenced and found to be 99% identical to C. pecorum by BLAST analysis. Other known abortigenic infectious agents were ruled out by specific testing. It is concluded that C. pecorum infection is associated with fetoplacental lesions and sporadic abortion in goats.

Isolation of Chlamydia abortus from a laboratory worker diagnosed with atypical pneumonia

Background

Identifying the aetiological agent of atypical pneumonia in human can sometimes be a tedious process, especially in cases where Mycoplasma pneumoniae, Legionella species and Chlamydia pneumoniae are ruled out. In such cases, a correct anamnesis of the patient is basic to clarify which pathogens might have produced the infection. For this reason, health professionals including veterinarians and laboratory personnel working with zoonotic pathogens should keep their doctors informed.

Case presentation

A human case of atypical pneumonia linked to Chlamydia abortus is reported. A 47-year-old male, a veterinarian researcher into chlamydiae, developed respiratory symptoms, breathing problems and high fever. Serological analyses ruled out the involvement of several respiratory pathogens, such as M. pneumoniae, Legionella pneumophila, Rickettsia conorii and C. pneumoniae, and Chlamydia abortus was identified as the possible aetiological agent of the infection. The isolation of C. abortus from the patient’s sputum and subsequent molecular analysis confirmed the presence of this microorganism.

Conclusion

As far as we know, although C. abortus has not been previously described as capable of causing pneumonia in humans, this is the first reported case of atypical pneumonia in which C. abortus is thought to have played an aetiological role.

Chlamydia-related abortions in Cattle from Graubunden, Switzerland

In 2001, the first case of bovine chlamydial abortion was reported in canton Graubunden, Switzerland. In this region, Chlamydophila (Cp.) abortus is endemic in small ruminants. Hence, we aimed to investigate the incidence of chlamydia-related abortions in cattle from Graubunden. During breeding seasons of 2003-2004, formalin-fixed and paraffin-embedded placenta specimens ( n = 235) from late-term abortions in cattle were analyzed by histopathology, immunohistochemistry with a Chlamydiaceae-specific monoclonal antibody against chlamydial lipopolysaccharide (LPS), and 2 different polymerase chain reaction (PCR) methods (16 S ribosomal ribonucleic acid [rRNA] PCR, intergenic spacer [IGS-S] PCR), followed by PCR product sequencing. In 149 of 235 cases (63.4%), histopathologic lesions such as purulent and/or necrotizing placentitis were observed. Chlamydial antigen was clearly demonstrated in immunohistochemistry in only 1 of 235 cases (0.4%). Cp. abortus or Cp. psittaci was found in 12 of 235 (5.1%) and 10 of 235 cases (4.2%) by 16 S rRNA PCR and IGS-S PCR, respectively. However, we detected, by 16 S rRNA PCR, 43 of 235 cases (18.3%) to be positive for chlamydia-like organisms. In contrast to the situation in small ruminants in the canton Graubunden, bovine abortion from Cp. abortus seems not to play an important role. Nevertheless, zoonotic potential should be taken into account when handling abortion material from cattle. The significance of chlamydia-like isolates other than Waddlia chondrophila remains an open question in abortion and needs further investigation.

Zoonotic risks from small ruminants

Zoonoses are infections that spread naturally between species (sometimes by a vector) from animals to other animal species or to humans or from humans to animals. Most of the zoonoses diagnosed in sheep and goats are transmitted by close contact of man with these animals and are, more often, occupational diseases that principally affect breeders, veterinarians and/or slaughterhouse workers. Some other diseases have an airborne transmission and affect the population in the vicinity of sheep/goat farms. Due to the fact that small ruminants are almost the only remaining animals which are migrating in industrialised countries, there is a severe risk for transmitting the diseases. Some other zoonotic diseases are foodborne diseases, which are mainly transmitted from animals to humans and to other animal species by contaminated food and water. Within the last decade central Europe was threatened by some new infections, e.g., bluetongue disease and schmallenberg disease, which although not of zoonotic interest, are caused by pathogens transmitted by vectors. Causal agents of both diseases have found highly effective indigenous vectors. In the future, climate change may possibly modify conditions for the vectors and influence their distribution and competence. By this, other vector-borne zoonotic infections may propagate into former disease free countries. Changes in human behaviour in consummation and processing of food, in animal housing and management may also influence future risks for zoonosis. Monitoring, prevention and control measures are proposed to limit further epidemics and to enable the containment of outbreaks. Measures depend mainly on the damage evoked or anticipated by the disease, the local situation, and the epidemiology of the zoonoses, the presence of the infective agent in wild and other animals, as well as the resistance of the causal microorganisms in the environment and the possibility to breed sheep and goats which are resistant to specific infections. In this review, the clinical signs in animals and humans of the main sheep and goat zoonoses, as well as the transmission route and the control measures are reported. Brucellosis, chlamydophilosis, Q fever, Orf, Rift valley fever and Bovine Spongiform Encephalopathy are described in greater detail, in order to determine factors that contribute to the choice of the control strategies.

Typing of Chlamydia psittaci to monitor epidemiology of psittacosis and aid disease control in the Netherlands, 2008 to 2013

Binary file ES_Abstracts_Final_ECDC.txt matches

Detection and genotyping of Chlamydia species responsible for reproductive disorders in Algerian small ruminants

Chlamydiosis in small ruminants is a zoonotic disease mainly related to Chlamydia abortus. This bacterium is responsible for abortions and reproductive disorders in sheep and goats. Stillbirth and infertility, leading to important economic losses, are also associated with this pathology. In Algeria, abortion cases are frequently reported by veterinarians but, except for brucellosis which is a notifiable disease in this country, abortive diseases are in general poorly studied. In order to detect and genotype Chlamydia species in small ruminants in different areas of Algeria, a study was conducted on samples collected from females (164 blood samples and 199 vaginal swabs) between October 2011 and March 2013. Serum samples were tested with a C. abortus-specific indirect ELISA test. Fourteen samples (8.5 %), from six farms (6/20, 30 %) were tested positive. Vaginal swabs were analysed with a real-time PCR targeting all Chlamydiaceae spp. Thirty samples (15 %) were diagnosed positive in 16 farms (16/25, 64 %). Positive samples were all re-tested with a C. abortus- and a C. pecorum-specific real-time PCR. Finally, 13/30 (43.3 %) and 6/30 (20 %) were identified as C. abortus and C. pecorum, respectively. Enough concentrated C. abortus samples were genotyped by multi-loci variable number of tandem repeat (VNTR) analysis (MLVA), and all were related to the genotype [2] group which mainly includes French C. abortus isolates. C. pecorum-positive samples were genotyped by multi-locus sequence typing (MLST). Interestingly, two of them were successfully genotyped and showed identical MLST sequences to VB2, AB10, E58 and SBE, a group which includes C. pecorum isolates considered as highly pathogenic. These findings suggest a possible role of C. abortus and C. pecorum strains in the aetiology of abortion in Algerian small ruminants.

Seroprevalence and risk factors of Chlamydia abortus infection in Tibetan sheep in Gansu province, northwest China

Chlamydia abortus, an important pathogen in a variety of animals, is associated with abortion in sheep. In the present study, 1732 blood samples, collected from Tibetan sheep between June 2013 and April 2014, were examined by the indirect hemagglutination (IHA) test, aiming to evaluate the seroprevalence and risk factors of C. abortus infection in Tibetan sheep. 323 of 1732 (18.65%) samples were seropositive for C. abortus antibodies at the cut-off of 1:16. A multivariate logistic regression analysis was used to evaluate the risk factors associated with seroprevalence, which could provide foundation to prevent and control C. abortus infection in Tibetan sheep. Gender of Tibetan sheep was left out of the final model because it is not significant in the logistic regression analysis (P > 0.05). Region, season, and age were considered as major risk factors associated with C. abortus infection in Tibetan sheep. Our study revealed a widespread and high prevalence of C. abortus infection in Tibetan sheep in Gansu province, northwest China, with higher exposure risk in different seasons and ages and distinct geographical distribution.

Molecular identification of chlamydial cause of abortion in small ruminants in Jordan

Chlamydophila abortus (Ch. abortus) is the etiological agent of ovine enzootic abortion (OEA) and one of the most common infectious agents of abortion in small ruminants worldwide. RFLP-PCR analysis of the outer membrane protein gene (OMP2 gene) was used for diagnosis and characterization of chlamydial causes of abortion in small ruminants in Jordan. Sixty-six placental tissues and 15 vaginal swabs were collected from aborted ewes and does to identify cause of abortion in Jordan. Thirty-eight placental samples (58 %) and 13 vaginal swabs (87 %) were positive for chlamydial DNA. Shedding of bacteria in vaginal swabs was detected within 7 days after abortion. The results of this study showed that chlamydiosis is one of the important causes of abortion in small ruminants in Jordan. In addition, vaginal swab is an excellent sample for molecular diagnosis of chlamydiosis. DNA sequencing and RFLP analysis of the OMP2 reveal that all chlamydial cause of abortion in small ruminants in Jordan are due to Ch. abortus. While, Ch. pecorum was not detected in any sample. OMP2 gene of the isolated Jordanian strain was identical (100 %) to Ch. abortus FAS strain. In conclusion, Ch. abortus is an important cause of abortion in Jordan; vaginal swab within 7 days of abortion can be used for molecular diagnosis of chlamydiosis in small ruminants.

High frequency of chlamydial co-infections in clinically healthy sheep flocks

Background

The epidemiological situation of ovine chlamydial infections in continental Europe, especially Germany is poorly characterised. Using the German state of Thuringia as a model example, the chlamydial sero- and antigen prevalence was estimated in thirty-two randomly selected sheep flocks with an average abortion rate lower than 1%. Seven vaccinated flocks were reviewed separately.

Results

A wide range of samples from 32 flocks were examined. Assumption of a seroprevalence of 10% (CI 95%) at flock level, revealed that 94% of the tested flocks were serologically positive with ongoing infection (i.e. animals with seroconversion) in nearly half (47%) of the flocks. On the basis of an estimated 25% antigen prevalence (CI 95%), PCR and DNA microarray testing, together with sequencing revealed the presence of chlamydiae in 78% of the flocks. The species most frequently found was Chlamydophila (C.) abortus (50%) followed by C. pecorum (47%) and C. psittaci genotype A (25%). Mixed infections occurred in 25% of the tested flocks. Samples obtained from the vaccinated flocks revealed the presence of C. abortus field samples in 4/7 flocks. C. pecorum was isolated from 2/7 flocks and the presence of seroconversion was determined in 3/7 flocks.

Conclusions

The results imply that chlamydial infections occur frequently in German sheep flocks, even in the absence of elevated abortion rates. The fact that C. pecorum and the potentially zoonotic C. psittaci were found alongside the classical abortifacient agent C. abortus, raise questions about the significance of this reservoir for animal and human health and underline the necessity for regular monitoring. Further studies are needed to identify the possible role of C. psittaci infections in sheep.

Multi locus sequence typing of Chlamydia reveals an association between Chlamydia psittaci genotypes and host species

Chlamydia comprises a group of obligate intracellular bacterial parasites responsible for a variety of diseases in humans and animals, including several zoonoses. Chlamydia trachomatis causes diseases such as trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Chlamydia pneumoniae is a common cause of community-acquired respiratory tract infections. Chlamydia psittaci, causing zoonotic pneumonia in humans, is usually hosted by birds, while Chlamydia abortus, causing abortion and fetal death in mammals, including humans, is mainly hosted by goats and sheep. We used multi-locus sequence typing to asses the population structure of Chlamydia. In total, 132 Chlamydia isolates were analyzed, including 60 C. trachomatis, 18 C. pneumoniae, 16 C. abortus, 34 C. psittaci and one of each of C. pecorum, C. caviae, C. muridarum and C. felis. Cluster analyses utilizing the Neighbour-Joining algorithm with the maximum composite likelihood model of concatenated sequences of 7 housekeeping fragments showed that C. psittaci 84/2334 isolated from a parrot grouped together with the C. abortus isolates from goats and sheep. Cluster analyses of the individual alleles showed that in all instances C. psittaci 84/2334 formed one group with C. abortus. Moving 84/2334 from the C. psittaci group to the C. abortus group resulted in a significant increase in the number of fixed differences and elimination of the number of shared mutations between C. psittaci and C. abortus. C. psittaci M56 from a muskrat branched separately from the main group of C. psittaci isolates. C. psittaci genotypes appeared to be associated with host species. The phylogenetic tree of C. psittaci did not follow that of its host bird species, suggesting host species jumps. In conclusion, we report for the first time an association between C. psittaci genotypes with host species.

Chlamydial zoonoses

BACKGROUND

Zoonoses were already a subject of intense interest even before the SARS and avian influenza epidemics arose. For many years, chlamydiae have been hypothesized to be important zoonotic pathogens, because of their wide distribution and their infectious cycle. This article provides an overview of the current state of knowledge on this subject.

METHODS

The authors present a selective review of the literature as well as their own findings.

RESULTS

The scientific knowledge of the distribution and infectious cycle of chlamydiae is still inadequate. The laboratory diagnosis of chlamydial zoonoses remains unsatisfactory in both human and veterinary medicine, as there are no commercially available sensitive and species-specific tests. Acute chlamydial infections are usually treated with macrolides, tetracyclines, or quinolones. Persistent varieties are not covered by standard therapy.

CONCLUSIONS

There is a considerable need for research on chlamydial infections, especially with regard to the diagnosis and treatment of persistent varieties.

Zoonotic potential of Chlamydophila

The purpose of this article is to present the diseases induced in humans and animals by the different species of Chlamydophila, after providing an overview on the history of these infectious agents and their taxonomy. The route of transmission and the available methods for prevention and control in the different animal species are reviewed.

High prevalence of antibodies against Chlamydiaceae and Chlamydophila abortus in wild ungulates using two "in house" blocking-ELISA tests

Few data are available on the prevalence and relevance of chlamydiae in wild mammals, and even fewer studies have been conducted to determine the prevalence of Chlamydophila abortus in wildlife hosts, most probably due to the absence of suitable species-specific serological assays for testing sera from wild animals. In light of this, we have developed two in-house blocking-ELISA tests for detection of antibodies against Chlamydiaceae and C. abortus in wild ungulates, and analyzed the relationship between geographical and biological factors and the prevalence of antibodies against Chlamydiaceae and C. abortus in 434 wild ungulates from Spain, including sera from European wild boar, Red deer, Fallow deer, Roe deer, Mouflon, Barbary sheep, Southern chamois, and Iberian ibex. Serology revealed that 41.7+/-4% of the sera were positive for the b-ELISA-LPS (Chlamydiaceae-specific) and 18.9+/-3% for the b-ELISA-rPOMP (C. abortus-specific). Antibodies against Chlamydiaceae lipopolysaccharide (LPS) were detected in sera from all eight ungulate species, the prevalence ranging from 23 to 60%. Iberian ibex was the only wild ungulate not showing seropositivity to the C. abortus specific polymorphic outer membrane protein (POMP). The prevalence of anti-POMP antibodies in the other seven wild ungulate species ranged from 7 to 40%. While significant seroprevalence differences were detected among species and among sampling regions, no effect of age and sex was observed. The high prevalence levels found should be considered with regards to livestock and human health, and warrant further research.

Recent developments in the laboratory diagnosis of chlamydial infections

There are two main approaches to diagnosing infections by Chlamydia and Chlamydophila spp. in mammals and birds. The first involves the direct detection of the agent in tissue or swab samples, while the second involves the serological screening of blood samples for the presence of anti-chlamydial antibodies. Ultimately, the test that is used is dependent on the types of samples that are submitted to the diagnostic laboratory for analysis. The present paper gives an overview on methodologies and technologies used currently in diagnosis of chlamydial infections with emphasis on recently developed tests. The performance characteristics of individual methods, such as the detection of antigen in smears and in pathological samples, the isolation of the pathogen, various antibody detection tests and DNA-based methods utilising conventional and real-time PCR, as well as DNA microarray technology are assessed, and specific advantages and drawbacks are discussed. Further, a combination of a specific real-time PCR assay and a microarray test for chlamydiae is proposed as an alternative reference standard to isolation by cell culture.

Molecular evidence for chlamydial infections in the eyes of sheep

Ocular infections by chlamydiae are associated with ocular disease manifestations such as conjunctivitis and keratitis in humans and animals. Limited evidence exists that members of the order Chlamydiales can also cause ocular disease in sheep. In the current study, the prevalence of chlamydiae in the eyes of sheep was investigated by using PCR methods. Data obtained in sheep by broad-range 16S rRNA order Chlamydiales-specific PCR were compared to the prevalence of antibodies against chlamydiae detected by a competitive enzyme-linked immunosorbent assay (cELISA). Flocks tested included a clinically healthy flock and two flocks suffering from ocular disease and with histories of Ovine Enzootic Abortion (OEA). PCR detected DNA of Chlamydophila (Cp.) abortus and Cp. pecorum in the eyes of both healthy and sick animals but also identified Chlamydia (C.) suis and a variety of uncultured chlamydia-like organisms. Good correlation was found between the presence of Cp. abortus DNA in sheep conjunctival samples and seropositivity detected by cELISA. Despite these findings, no association was found between the presence of chlamydial DNA in the sheep conjunctival samples and the onset of clinical disease. These results suggest that the biodiversity of chlamydiae in the eyes of sheep is greater than that previously thought. Further investigations are needed to determine whether a causal relationship between infection by chlamydiae and ocular disease exists in these animals.

Chlamydiae in free-ranging and captive frogs in Switzerland

A total of 210 frog samples originating either from a mass mortality (1991/1992) or from routine postmortem investigations of the years 1990 to 2004 were examined retrospectively for a possible involvement of Chlamydiae. For a prevalence study of Chlamydia in a selected Swiss amphibian population, 403 samples from free-ranging Rana temporaria were examined. Histopathology, immunohistochemistry using a monoclonal antibody against chlamydial lipopolysaccharide, and a 16S rRNA polymerase chain reaction (PCR) followed by DNA sequencing were performed on the formalin-fixed and paraffin-embedded tissues. Using PCR, 8 of 54 (14.8%) frog samples from the mass mortality (1991/1992) were positive for Chlamydia suis S45. A control group of healthy Xenopus laevis had 3 of 38 positive samples, sequenced as C suis S45 (2/3) and an endosymbiont of Acanthamoeba species UWE1 (1/3). Chlamydophila pneumoniae TW-183 was detected from exotic frogs kept in a zoo. Of the frogs collected for the prevalence study, 6 of 238 (2.5%) tested positive, 1 each for C suis S45, Cp pneumoniae TW-183, and uncultured Chlamydiales CRG22, and the remaining 3 revealed Chlamydophila abortus S26/3. In immunohistochemistry, there were 2 positive labeling reactions, 1 in intestine and the other in the epithelium coating the body cavity, both testing positive for Cp pneumoniae TW-183 in PCR. Histologically there were no lesions recorded being characteristic for Chlamydia. Although there is a prevalence of Chlamydia in Swiss frogs, no connection to a mass mortality (1991/1992) could be established. For the first time, C suis S45 and Cp abortus S26/3 were detected in frog material.

Effects of a probiotic strain of Enterococcus faecium on the rate of natural chlamydia infection in swine

Chlamydiae are obligately intracellular pathogens which cause infections associated with a broad range of diseases in both livestock and humans. In addition, a large proportion of animals may become persistently infected asymptomatic carriers and serve as reservoirs for other animals which also shed these potential zoonotic pathogens. Reducing the chlamydial load of animals is therefore of major importance, and since large-scale antibiotic treatment is neither desired nor feasible, alternative means of prevention are needed. Here we performed a study comparing the efficacy of a probiotic strain of Enterococcus faecium on the reduction of both the rate of natural infection and the shedding of chlamydiae in swine. The presence of Chlamydiaceae was detected by species-specific PCR of fecal samples of sows taken at three times prior to the birth of piglets. Piglets delivered from chlamydia-positive sows in either the control or the probiotic group were also examined for the frequency of chlamydiae at various ages. Eighty-five percent of the piglets from the control group were found to be chlamydia positive, whereas chlamydiae were found in only 60% of piglets from the probiotic group, results confirmed by fluorescence in situ hybridization and immunohistology, which showed higher rates of infection in the control group. In addition to the reduced frequency of chlamydia-positive piglets in the probiotic group, the time of appearance of positive samples was delayed. To our knowledge, these data show for the first time that a probiotic strain of E. faecium can reduce the rate of carryover infections of piglets by obligate intracellular pathogens.

Fetal death: comparative aspects in large domestic animals

Although the majority of pregnancy failures occur during the embryonic period, reports indicate that approximately 5% of detected pregnancies are lost during the fetal period, underlining the fact that fetal death is a substantial cause of economic loss. However, examination for fetal development or death during pregnancy is not performed routinely in domestic animals, and reference curves for normal fetal growth are, therefore, scarce. In this paper, the numerous possible causes of fetal death are reviewed briefly, with emphasis on the role of placental problems in fetal death and impaired fetal viability. In this respect, the role of placental insufficiency as a cause of pregnancy loss in twin pregnancies in monotocous species is well known, whereas the abnormal placental development leading to retarded fetal growth during pregnancies in recipients of in vitro produced (IVP) or nuclear transfer (NT) embryos has been less extensively documented. Fetal viability or death can be evaluated using hormonal, chemical and ultrasonographic parameters. For example, the viability of the feto-placental unit can be examined by measuring maternal plasma concentrations of oestrone sulphate or the placental proteins, including pregnancy-associated glycoprotein (PAG) and pregnancy-specific protein B-60 (PSPB-60). Low concentrations of any of these three indicate either no pregnancy, or if pregnancy was confirmed earlier, fetal death and abnormally high or low levels can indicate fetal abnormality. Ultrasound can be used to examine the fetal heart rate (FHR), the incidence of fetal movements (FM), the appearance of fetal fluids and the development of the fetus and placenta. However, although abnormal FHRs have been correlated to subsequent fetal death, it is important to remember that there is a large physiological variation in FHR at the end of gestation, due to different behavioural states and differences in FM patterns. Although monitoring fetal viability and death using hormonal and ultrasonographic evaluations is possible during pregnancy in domestic animals, there is considerable physiological variations in the 'normal' values. Therefore, suitable combinations of tests need to be identified and more accurate reference values generated before such approaches can be considered reliable for monitoring the status of individual fetuses.

Seroprevalences for ovine enzootic abortion in Switzerland

Our aim was to assess the seroprevalence of Chlamydophila (Cd) abortus (Chlamydia psittaci serotype 1), denoted ovine enzootic abortion (OEA), in the Swiss sheep population. A competitive enzyme-linked immunosorbent assay (cELISA) was adapted for the investigation of pooled serum samples (pool approach) and receiver-operator characteristic (ROC) analysis was applied to define the cut-off of the pool approach. At a cut-off value of 30% inhibition, the flock-level pooled sensitivity and specificity were 92.9% and 97.6% when compared to classifying the flock based on individual-animal samples. Subsequently, sera from 775 randomly selected flocks out of 11 cantons of Switzerland were investigated using the pool approach. The cantons included in the study represented 72% of the Swiss sheep flocks and 76% of Swiss sheep population. Antibodies against Cd. abortus were found in almost 19% (144) of the 775 examined sheep flocks. Test prevalences were adjusted for the imperfect test characteristics using the Rogan-Gladen estimator and Bayesian inference. Seroprevalence was highest (43%) in the canton Graubunden. In the remaining 10 cantons the seroprevalence ranged from 2 to 29%. The cELISA in combination with testing pooled sera and statistical methods for true prevalence estimation provided a good survey tool at lower costs and time when compared to other approaches.

Abortive potency of Chlamydophila abortus in pregnant mice is not directly correlated with placental and fetal colonization levels

Abortion, placental and fetal colonization, and levels of gamma interferon were analyzed for four Chlamydophila abortus strains presenting antigenic variations in a mouse model. Expression of virulence of these strains varied and indicated that abortion was not directly related to the number of bacteria in the placenta, and thus, other factors may have an important role in activating the abortion process.