Analysis of Humoral Immune Responses to Surface and Virulence-Associated Chlamydia abortus Proteins in Ovine and Human Abortions by Use of a Newly Developed Line Immunoassay
J Clin Microbiol. 2016 Jul;54(7):1883-1890. doi: 10.1128/JCM.00351-16. Epub 2016 May 18.
The obligate intracellular bacterium Chlamydia abortus is the causative agent of enzootic abortion of ewes and poses a significant zoonotic risk for pregnant women. Using proteomic analysis and gene expression library screening in a previous project, we identified potential virulence factors and candidates for serodiagnosis, of which nine were scrutinized here with a strip immunoassay. We have shown that aborting sheep exhibited a strong antibody response to surface (MOMP, MIP, Pmp13G) and virulence-associated (CPAF, TARP, SINC) antigens. While the latter disappeared within 18 weeks following abortion in a majority of the animals, antibodies to surface proteins persisted beyond the duration of the study. In contrast, nonaborting experimentally infected sheep developed mainly antibodies to surface antigens (MOMP, MIP, Pmp13G), all of which did not persist. We were also able to detect antibodies to these surface antigens in C abortus-infected women who had undergone septic abortion, whereas a group of shepherds and veterinarians with occupational exposure to C abortus-infected sheep revealed only sporadic immune responses to the antigens selected. The most specific antigen for the serodiagnosis of human C abortus infections was Pmp13G, which showed no cross-reactivity with other chlamydiae infecting humans. We suggest that Pmp13G-based serodiagnosis accomplished by the detection of antibodies to virulence-associated antigens such as CPAF, TARP, and SINC may improve the laboratory diagnosis of human and animal C abortus infections.
Profiling antibody responses to infections by Chlamydia abortus enables identification of potential virulence factors and candidates for serodiagnosis
PLoS One. 2013 Nov 15;8(11):e80310. doi: 10.1371/journal.pone.0080310. eCollection 2013.
Enzootic abortion of ewes (EAE) due to infection with the obligate intracellular pathogen Chlamydia (C.) abortus is an important zoonosis leading to considerable economic loss to agriculture worldwide. The pathogen can be transmitted to humans and may lead to serious infection in pregnant women. Knowledge about epidemiology, clinical course and transmission to humans is hampered by the lack of reliable diagnostic tools. Immunoreactive proteins, which are expressed in infected animals and humans, may serve as novel candidates for diagnostic marker proteins and represent putative virulence factors. In order to broaden the spectrum of immunogenic C. abortus proteins we applied 2D immunoblot analysis and screening of an expression library using human and animal sera. We have identified 48 immunoreactive proteins representing potential diagnostic markers and also putative virulence factors, such as CAB080 (homologue of the “macrophage infectivity potentiator”, MIP), CAB167 (homologue of the “translocated actin recruitment protein”, TARP), CAB712 (homologue of the “chlamydial protease-like activity factor”, CPAF), CAB776 (homologue of the “Polymorphic membrane protein D”, PmpD), and the “hypothetical proteins” CAB063, CAB408 and CAB821, which are predicted to be type III secreted. We selected two putative virulence factors for further characterization, i.e. CAB080 (cMIP) and CAB063, and studied their expression profiles at transcript and protein levels. Analysis of the subcellular localization of both proteins throughout the developmental cycle revealed CAB063 being the first C. abortus protein shown to be translocated to the host cell nucleus.
Presence of Chlamydophila psittaci DNA in the central nervous system of a patient with status epilepticus
Scand J Infect Dis. 2003;35(1):71-3. doi: 10.1080/0036554021000026984.
This study reports an extraordinarily severe and prolonged course of neuroornithosis with generalized status epilepticus as an initial symptom. Direct invasion of the central nervous system by Chlamydophila psittaci was confirmed by the demonstration of specific DNA in the patient’s cerebrospinal fluid. The patient recovered slowly under administration of doxycycline.
Links: PMID: 12685890; DOI: 10.1080/0036554021000026984
Gernot Walder1, Walter Gritsch, Christian J Wiedermann, Gerhard Pölzl, Günther Laufer, Helmut Hotzel, Angela Berndt, Sabine Pankuweit, Dirk Theegarten, Olaf Anhenn, Albrecht Oehme, Manfred P Dierich, Reinhard Würzner
Crit Care Med. 2007 Feb;35(2):623-6. doi: 10.1097/01.CCM.0000254726.57339.C8.
Objective: The aim of this study is to describe a case of fulminant myocarditis caused by co-infection with Chlamydophila pneumoniae and Chlamydophila psittaci in order to facilitate diagnosis and clinical management of patients suffering from this rare but life-threatening condition.
Design: Case report.
Setting: Intensive care unit of Innsbruck Medical University.
Patient: A 24-yr-old patient admitted with septicemia and cardiac failure.
Interventions: Cardiopulmonary resuscitation, extracorporal membrane oxygenation, implantation of an extracorporal cardiac assist device, and antibiotic treatment with erythromycin.
Measurements and main results: Cp. pneumoniae and Cp. psittaci were identified by means of polymerase chain reaction and electron microscopy in the patient’s myocytes. Successful weaning off the ventricular assist device was performed within 2 wks after commencement of antibiotic therapy.
Conclusions: This case report demonstrates co-infection with Cp. pneumoniae and Cp. psittaci to be a hitherto unknown cause of fulminant myocarditis. There is a particular risk of misdiagnosis of viral myocarditis, which must be avoided. Patients should be transferred to a center where extracorporal membrane oxygenation therapy and molecular diagnosis of all members of the family Chlamydiaceae are available.
Links: PMID: 17204998; DOI: 10.1097/01.CCM.0000254726.57339.C8
Obstet Gynecol. 2005 Nov;106(5 Pt 2):1215-7. doi: 10.1097/01.AOG.0000161060.69470.9c.
Background: Chlamydophila abortus (formerly Chlamydia psittaci serovar 1) is a rare but severe cause of gestational septicemia, with particular problems in diagnosis and clinical management.
Case: A 32-year-old woman in her fourth pregnancy (16th week of gestation) presented with progressive septicemia after extensive contact with abortive material from her goat flock. Treatment with levofloxacin could not prevent abortion. Multiorgan failure requiring catecholamines and artificial ventilation developed in the patient. After the agent was identified by polymerase chain reaction from acute-phase serum, macrolides were administered and yielded clinical improvement. The patient fully recovered. There were no sequelae in the subsequent 6 months.
Conclusion: Cp abortus must be considered in gestational septicemia after contact with ruminants. Polymerase chain reaction from acute-phase serum is a quick and easy way to establish the diagnosis. Macrolide antibiotics are still the treatment of choice.
Links: PMID: 16260577; DOI: 10.1097/01.AOG.0000161060.69470.9c
Emerg Infect Dis. 2003 Dec;9(12):1642-4. doi: 10.3201/eid0912.020566.
We report the first documented case of an extragestational infection with Chlamydophila abortus in humans. The pathogen was identified in a patient with severe pelvic inflammatory disease (PID) by sequence analysis of the ompA gene. Our findings raise the possibility that Chlamydiaceae other than Chlamydia trachomatis are involved in PID.