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PubMed1980

Environmental exposure to Coxiella burnetii: a sero-epidemiologic survey among domestic animals.

The prevalence of agglutinating serum antibodies against Coxiella burnetii, the cause of Q fever in humans, was tested in a hospital population of companion animals and livestock in California during 1973--1975. A sample of stray dogs was also tested. Among the hospitalized animals 346 (48%) of 724 dogs, 7 (9%) of 80 cats, 9 (32%) of 28 cattle and 31 (26%) of 121 horses had antibodies against C. burnetii. Of 316 stray dogs 208 (66%) were seropositive. The overall prevalence of 53% among 1040 dogs tested was comparable to the 63% antibody prevalence found in an earlier survey among coyotes and foxes in wildlife areas of California. When the dog was considered as a sentinel animal for the presence of C. burnetii surrounding household environments, it was hypothesized that the common, low level exposures in the community are similar to those found in more remote wildlife areas.

Animals↗

PubMed1994

Coxiella burnetii infection of pseudoaneurysm of an aortic bypass graft with contiguous vertebral osteomyelitis.

We report the case of a 67-year-old man who had an infection of a pseudoaneurysm of an aortic graft with contiguous vertebral osteomyelitis. The infectious organism was identified as Coxiella burnetii, a strict intracellular pathogen causing Q fever infection in humans. The patient was treated successfully with removal of the infected material in conjunction with extraanatomic bypass and specific antibiotic therapy. He is doing well after more than 3 years, with no evidence of recurrent periaortic infection on successive computed tomographic scans. We suspect that C. burnetii vascular graft infections could be underdiagnosed, because this cause is not frequently evoked. We suggest that extending the etiologic search to C. burnetii could decrease the number of undocumented vascular graft infections.

Aged↗

PubMed1978

Prevalence of Coxiella burnetii (Q fever) and Toxoplasma gondii among dairy goats in California.

The prevalence of antibodies against Coxiella burnetii and Toxoplasma gondii, the causative agents of Q fever and toxoplasmosis, was examined in goats to determine the extent of the potential of goats to tansfer these infections to persons. Of 1,054 goats from 234 premises in California, 248 goats (24%) were seropositive for C burnetii and 246 (23%) were seropositive for T gondii. Of 29 dairy goats tested, 2 (7%) were found to be shedding the Q fever rickettsia in their milk; T gondii was not detected. Factors of sex, age, location, and herd size are discussed.

Age Factors↗

PubMed1997

Analysis of immunoglobulin classes and subclasses in response to infection of Balb/cJ and C57BL/6J mice with Coxiella burnetii.

In order to establish defined immunological parameters for Q fever infection models, a microtitre enzyme-linked immunosorbent fluorescence assay (ELISA) was used for the first time to analyse the humoral immune response of Balb/cJ and C57BL/6J mice after experimental infection with Coxiella burnetii strain 'Nine Mile' in phase I. The experimental infection evoked a seroconversion in all mice within 10 days. Typically, the immune response measured against the whole-cell antigen showed an early increase of immunoglobulin (Ig) M followed by a later increase of the IgG subclasses. The IgA was low during the entire investigation period. Within the IgG subclasses only IgG2a and IgG2b gained higher values, whereby C57BL/6J mice produced high IgG2b titres and significantly lower IgG2a titres. In contrast, Balb/cJ mice developed IgG2a and IgG2b at equal levels. The use of partial antigens of C. burnetii demonstrated that the dominating IgG2b reaction of the C57BL/6J mice was directed against the lipopolysaccharide (LPS) of C. burnetii. This reaction was almost absent in Balb/cJ mice. In contrast, the SP27 protein antigen did not evoke different IgG2b reactions within the two breeds. No significant influence was observed within the two breeds in regard to sex or between hormone synchronized and non-hormone synchronized animals.

Animals↗

PubMed1993

Variation in interferon-gamma responses to Coxiella burnetii antigens with lymphocytes from vaccinated or naturally infected subjects.

Previous work in our laboratory has shown that lymphocytes from persons vaccinated with a formalin-inactivated Phase I Q fever vaccine (Q-Vax CSL Ltd) show a mitogenic response to Coxiella burnetii antigens. The mitogenic response is the sum of that from various subsets of CD4+, T helper cells, CD8+ T cells and probably B cells. It does not distinguish between T helper cell responses leading to formation of interferon-gamma (IFN-gamma)--a cytokine responsible for clearing intracellular infection with C. burnetii organisms--and responses of other T cell subsets which may produce disease-enhancing cytokines. The present study analyses (i) the capacity of Q-Vax to induce T cell sensitization which leads to IFN-gamma responses on antigen stimulation, and (ii) the immunomodulatory, (down-regulatory) effects of the Phase I lipopolysaccharide (LPS) of the organism, which interacts with monocyte/macrophages to limit IL-2 production and production of IFN-gamma by sensitized T lymphocytes.

Antigens, Bacterial↗

PubMed2006

Detection of Anaplasma phagocytophilum, Coxiella burnetii, Rickettsia spp., and Borrelia burgdorferi s. l. in Ticks, and wild-living animals in western and middle Slovakia.

In this study, three tick species (Ixodes ricinus, Dermacentor marginatus, and D. reticulatus), small terrestrial mammals, and game were examined by PCR for the presence of tick-borne pathogens Anaplasma phagocytophilum, Coxiella burnetii, Rickettsia spp., and Borrelia burgdorferi Sensu lato.

Anaplasma phagocytophilum↗

PubMed1998

Synthesis in Escherichia coli of two smaller enzymically active analogues of Coxiella burnetii macrophage infectivity potentiator (CbMip) protein utilizing a single open reading frame from the cbmip gene.

FK506-binding proteins (FKBPs) have been identified in a variety of eukaryotic and prokaryotic organisms. Macrophage infectivity potentiator (CbMip, 23.5 kDa) protein of the obligate intracellular bacterium, Coxiella burnetii, was shown previously to belong to the family of FKBPs based on sequence homology and peptidyl-prolyl cis/trans isomerase (PPIase) activity. Further characterization of the cbmip gene has identified two additional proteins with molecular masses of 15.5 and 15.0 kDa that are synthesized, in addition to the 23.5 kDa CbMip, when expressed in Escherichia coli. Amino acid sequencing at the N-terminus combined with transcription and translation fusion expression revealed that the two proteins were synthesized from the same open reading frame of the cbmip gene, but starting at different internal translation start codons, probably by translational reinitiation. When the internal methionines serving as start sites were replaced with lysine by site-directed mutagenesis, the synthesis of 15.5 and 15.0 kDa proteins was abolished even though the synthesis of 23.5 kDa CbMip was intact. This confirmed that the 15.5 and 15.0 kDa proteins are indeed generated by translational reinitiation and are not degradation products of the 23.5 kDa protein. Like other FKBPs, both 15.5 and 15.0 kDa proteins exhibit PPIase activity. Because they share significant sequence homology with FKBPs and have a similar PPIase activity, 15.5 and 15. 0 kDa proteins are designated as C. burnetii FKBP (Cb-FKBP) analogues I and II, respectively. TnphoA mutagenesis demonstrated that whereas the large protein (CbMip) is secreted, Cb-FKBP analogues I and II are cytoplasmic, indicating that structural variations could allow for different subcellular compartmentalization of similar proteins. Western-blot analysis of lysates of purified C. burnetii using a CbMip-specific monoclonal antibody revealed the presence of a protein migrating at approximately 15 kDa, indicating the presence of smaller Cb-FKBP analogue(s) in C. burnetii, although at much lower levels compared with 23.5 kDa CbMip. This unique gene organization seen with cbmip may provide the organism with a mechanism of efficient use of its limited genetic information to synthesize proteins that are structurally different yet functionally similar.

Amino Acid Sequence↗

PubMed1987

Comparison of enzyme-linked immunosorbent assay and complement fixation and indirect fluorescent-antibody tests for detection of Coxiella burnetii antibody.

An enzyme-linked immunosorbent assay (ELISA) was developed to detect immunoglobulin G to Coxiella burnetii phase II. Serum samples from 213 patients who had had Q fever 1 year previously and from 301 blood donors from six localities in Switzerland were tested by ELISA and by indirect fluorescent-antibody (IFA) and complement fixation (CF) tests. The ELISA and the IFA and CF tests detected antibody to C. burnetii in 202 (94.8%), 193 (90.6%), and 166 (77.8%) of the 213 Q fever patients, respectively. With the serum samples from blood donors, the ELISA yielded a higher percentage of positive sera than did the IFA and CF tests. The high specificity of the three tests was confirmed by analyzing paired serum samples from 36 patients suffering from acute pneumonia of viral or bacterial origin. In these cases, the serological results were negative by the three tests, except for three Q-fever cases included as positive control.

Antibodies, Bacterial↗

PubMed1972

Purification of large quantities of coxiella burnetii rickettsia by density gradient zonal centrifugation.

The purification of large quantities of inactivated, phase II Coxiella burnetii by isopycnic zonal centrifugation for use as diagnostic antigen and as a vaccine is described. The fractionation of egg yolk sac-derived C. burnetii vaccine resulted in the separation of two distinct populations of organisms, each devoid of microscopically and serologically recognizable components of egg yolk sac. One population of organisms, characterized by an equilibrium density of 1.240, was rod shaped (1.0 by 0.5 mumole) with a thick, densely strained wall and prominent central body. The second population, with an equilibrium density of 1.280, had a coccobacillary shape (approximately 1 mumole in diameter), granular, sometimes fibrillar cytoplasm, thin cellular walls, and lacked a prominent nucleoid.

Animals↗

PubMed1978

Immunological properties of the lipopolysaccharide-protein complex of Coxiella burnetii.

Purified lipopolysaccharide-protein complex (LPS-PC) extracted by trichloroacetic acid from phase I Coxiella burnetii organisms induced in mice and rabbits fair levels of antibodies directed to antigen 1 and antigen 2, as detected by complement-fixation (CF), microagglutination (MA), opsonization-phagocytosis (OP) and serum protection (SP) tests. In guinea pigs only very low levels of MA antibodies against antigen 2 were demonstrated. In rabbit serum, MA antibodies directed to antigen 2 were found exclusively in the IgM fraction after the primary immunizing dose; the second dose was followed by gradual shift of MA antibodies to the IgG class. Two immunizing doses of the LPS-PC were more effective when testing antibody response in mice or protection of mice and guinea pigs against phase I virulent challenge.

Agglutination Tests↗

PubMed1981

Evaluation of a killed phase I Coxiella burnetii vaccine in cynomolgus monkeys (Macaca fascicularis).

The protective efficacy of a killed, purified, phase I Coxiella burnetii vaccine was tested in cynomolgus monkeys. Monkeys vaccinated once with 30 micrograms of the antigen were challenged 6 or 12 months later with virulent phase I rickettsiae administered in small-particle aerosols. The vaccine provided only partial protection, since some of the challenged monkeys developed clinical signs of illness. However, the vaccinated animals did not develop pneumonia as determined by radiographic evaluation nor any hematologic or chemical changes except for an increase in fibrinogen. Although rickettsiae were isolated from peripheral blood in vaccinated monkeys, the rickettsemia persisted for only 1-2 days; whereas, organisms were recovered from unvaccinated animals for 6-7 days. All vaccinated animals had circulating microagglutinating antibodies to phase I and phase II antigens 6 and 12 months after vaccination.

Animals↗

PubMed1976

Interaction between Coxiella burnetii and guinea pig peritoneal macrophages.

The phagocytosis and subsequent degradation of phase I and II Coxiella burnetii by macrophages obtained from immune and nonimmune guinea pigs were compared. Phase I rickettsiae were more resistant to phagocytosis than were phase II organisms. There was no significant difference in the percentage of phagocytosis of either phase of rickettsiae by macrophages from immune or nonimmune animals. After ingestion, phase I and II organisms pretreated with normal serum multiplied and destroyed normal macrophages as well as macrophages obtained from guinea pigs immunized with phase II rickettsiae. In contrast, only phase I organisms were degraded by macrophages from phase I-immunized animals in the presence of normal serum. Immune serum rendered rickettsiae more susceptible to phagocytosis and also potentiated the destruction of organisms by all types of macrophages. The specificity of macrophages from phase I animals to degrade only phase I rickettsiae was demonstrated by the ability of Rickettsia rickettsii to replicate in these macrophages.

Animals↗

PubMed1994

[The effect of herd and animal factors on the detection of complement-binding antibodies against Coxiella burnetii in cattle].

To determine the prevalence of bovine Coxiella (C.) burnetii infections in Northern Lower Saxony, blood serum obtained from a total of 2160 cattle was examined for antibodies against C. burnetii using the complement fixation test (CFT). From 500 randomly sampled cattle, 38 (7.6%) were seropositive. In 383 cows out of 33 dairy herds with the history of reproductive problems a significantly higher prevalence of C. burnetii specific antibodies was found than in 665 cows out of 39 herds without reproductive problems (19.3% vs. 9.6%). In both groups, mean CFT titer increased significantly with the degree of the within herd prevalence. Furthermore, in dairy herds with fertility problems the within herd prevalence was significantly higher than in dairy herds not experiencing infertility (24.3% vs. 11.2%). A relationship between serological evidence of C. burnetii infection and incidence of reproductive disorders observed in lowered fertility herds was not found. Statistical analysis of CFT results of 668 cows allocated in groups according to month of gestation, month prior insemination, and month postpartum revealed that the percentage of seropositives as well as CFT titers rise significantly in the 1st month of gestation and after a sharp decline in the 4th month increase a second time in the 7th month of gestation. Sera from 612 bulls aged six months to ten years yielded 5.2% seropositives. The most positives (87.5%) were found in bulls aged up to two and a half year. After a six month period, 428 bulls were retested. Specific antibodies were found in eight (27.6%) of 29 formerly seropositives. Seroconversion was not detected in any of 399 formerly seronegative bulls.

Animals↗

PubMed2005

Effect of vaccination with phase I and phase II Coxiella burnetii vaccines in pregnant goats.

Livestock is considered to be the major "source" of human Q fever. The efficacy of two currently available vaccines (Coxevac, phase I, CEVA Santé Animale and Chlamyvax FQ, phase II, MERIAL) against Coxiella excretion was investigated in terms of risks to human health. Two months before mating, 17 goats were vaccinated subcutaneously against Coxiella burnetii with an inactivated phase I vaccine and 16 goats were vaccinated with an inactivated phase II Coxiella mixed with Chlamydophila abortus vaccine. Fourteen goats were left unvaccinated. At 84 days of gestation, the goats were subcutaneously challenged with 10(4) bacteria of C. burnetii strain CbC1. Phase I vaccine was effective and dramatically reduced both abortion and excretion of bacteria in the milk, vaginal mucus and feces. In contrast, the phase II vaccine did not affect the course of the disease or excretion.

Animals↗

PubMed1987

Cloning and functional expression of the Coxiella burnetii citrate synthase gene in Escherichia coli.

The citrate synthase gene from the obligate intracellular rickettsial parasite Coxiella burnetii was cloned and expressed in Escherichia coli. Transduction into E. coli with a C. burnetii gene library constructed in the cosmid vector pHK17 resulted in the functional complementation of the gltA mutation of E. coli MOB154. A GltA+ clone carrying 16.4 kilobase pairs of C. burnetii DNA and designated pJCC959 was isolated and characterized. Southern hybridization analysis confirmed that the pJCC959 cloned insert consists of C. burnetii DNA and that homology exists with the Rickettsia prowazekii citrate synthase gene. Subcloning analysis with the multicopy expression vector pUC8 revealed that citrate synthase expression was under control of a C. burnetti promoter. In vitro transcription-translation of subclones pLPM20 and pLPM30 established a molecular weight of ca. 46,000 for the monomer form of the cloned enzyme. Transposon Tn5 mutagenesis of pLPM30 defined the coding region to approximately 1.2 kilobase pairs of C. burnetii DNA. Maxicell analysis of selected pLPM30::Tn5 insertion derivatives identified the direction of transcription and the relative translational start and stop sites and substantiated the molecular weight value calculated from the in vitro analysis. Inhibition studies showed that citrate synthase activity in crude cell extracts obtained from strain MOB154 transformed with the cloned C. burnetii gene was markedly inhibited by 4 mM ATP, while 4 mM alpha-ketoglutarate had virtually no effect. These data indicate that the C. burnetii enzyme displays regulatory behavior characteristic of the small gram-positive bacterial and eucaryotic enzyme.

Adenosine Triphosphate↗

PubMedDate not supplied

Experimental infection of Coxiella burnetii in chicken: clinical symptoms, serologic response, and transmission through egg.

Young laying hens were infected with Coxiella burnetii to study egg transmission, clinical and serologic responses, excretion of the agent in feces, and its persistence in internal organs. No clinical symptoms were noticed. The birds developed good titers in a capillary agglutination test by 13 days postinfection (DPI), which peaked at 30 DPI and therafter declined gradually, becoming negative in some birds around 90 DPI. In vivo and in vitro egg transmission of the agent could not be demonstrated. C. burnetii was recovered at 90 DPI from spleen and liver but not from kidney and ovary.

Agglutination Tests↗

PubMed2002

Nitric oxide inhibits Coxiella burnetii replication and parasitophorous vacuole maturation.

Nitric oxide is a recognized cytotoxic effector against facultative and obligate intracellular bacteria. This study examined the effect of nitric oxide produced by inducible nitric oxide synthase (iNOS) up-regulated in response to cytokine stimulation, or by a synthetic nitric oxide donor, on replication of obligately intracellular Coxiella burnetii in murine L-929 cells. Immunoblotting and nitrite assays revealed that C. burnetii infection of L-929 cells augments expression of iNOS up-regulated in response to gamma interferon (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha). Infection in the absence of cytokine stimulation did not result in demonstrable up-regulation of iNOS expression or in increased nitrite production. Nitrite production by cytokine-treated cells was significantly inhibited by the iNOS inhibitor S-methylisothiourea (SMT). Treatment of infected cells with IFN-gamma and TNF-alpha or the synthetic nitric oxide donor 2,2'-(hydroxynitrosohydrazino)bis-ethanamine (DETA/NONOate) had a bacteriostatic effect on C. burnetii replication. Inhibition of replication was reversed upon addition of SMT to the culture medium of cytokine-treated cells. Microscopic analysis of infected cells revealed that nitric oxide (either cytokine induced or donor derived) inhibited formation of the mature (large) parasitophorous vacuole that is characteristic of C. burnetii infection of host cells. Instead, exposure of infected cells to nitric oxide resulted in the formation of multiple small, acidic vacuoles usually containing one C. burnetii cell. Removal of nitrosative stress resulted in the coalescence of small vacuoles to form a large vacuole harboring multiple C. burnetii cells. These experiments demonstrate that nitric oxide reversibly inhibits replication of C. burnetii and formation of the parasitophorous vacuole.

Animals↗

PubMed1992

Primary humoral antibody response to Coxiella burnetii, the causative agent of Q fever.

Of 147 patients with acute Q fever diagnosed during a major outbreak in Birmingham, England, in early summer 1989, 41 provided sets of sera which allowed us to make a detailed analysis of the primary humoral immune response. Antibody titers specific for Coxiella burnetii were measured by the complement fixation test and by an immunoglobulin M (IgM)- and IgG-specific indirect immunofluorescence test. The relative avidity of specific IgGs was determined by the indirect immunofluorescence test with and without treatment of antigen-antibody complexes with 8 M urea. The IgG subclass responses after primary infection and their avidities were also determined for a limited number of paired serum specimens. Specific IgM titers persisted for more than 6 months in the majority of cases and were therefore not a sufficient criterion for the diagnosis of recent infection. However, for serial samples the antibody titer ratios (IgG/IgM) and the ratios (IgG titer with treatment/IgG titer without treatment) that indicated relative avidity changed significantly, depending on the time postinfection. Within the IgG class, the C. burnetii-specific antibody response over time was almost exclusively represented by subclass 1 molecules, which thus showed affinity maturation.

Antibodies, Bacterial↗