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PubMed2002

Current laboratory diagnosis of Q fever.

Q fever is a worldwide zoonosis caused by the strictly intracellular bacterium Coxiella burnetii. Among symptomatic patients (one-half of patients remain asymptomatic), acute Q fever most frequently manifests as a self-limited febrile illness, pneumonia, or hepatitis. Endocarditis is the predominant form of chronic Q fever. All the classical techniques of bacteriology may be used for diagnosis of C burnetii infection. Nonetheless, because of the risk of contamination, isolation must be performed in biosafety level 3 laboratories. Moreover, to date no diagnostic tests for detection by polymerase chain reaction or specific antibodies for immunochemistry are available commercially. Hence, Q fever is diagnosed in most cases by serology. The most reliable technique appears to be micro-immunofluorescence, which exhibits both good sensitivity and specificity. A wider use of this serology in cases of blood culture-negative endocarditis, atypical pneumonia, unexplained fever, and hepatitis should lead to an increase of diagnosed cases.

Animals↗

PubMed2002

Doxycycline and chloroquine as treatment for chronic Q fever endocarditis.

Endocarditis is a rare but severe complication of Q fever, an infectious disease caused by the intracellular pathogen Coxiella burnetii. Heart involvement is the most common clinical presentation of chronic Q fever, and it occurs almost invariably in patients with previous valvular disease or artificial valves, and in the immunocompromised host. The optimal treatment of Q fever endocarditis is still today debated, and recommended duration of treatment varies from one year to one's lifespan. A case of chronic Q fever endocarditis is described in a patient with biological prosthetic aortic valve and aortic homograft, successfully treated with doxycycline and chloroquine for 2 years.

Anti-Bacterial Agents↗

PubMed2005

Insights into genome plasticity and pathogenicity of the plant pathogenic bacterium Xanthomonas campestris pv. vesicatoria revealed by the complete genome sequence.

The gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria is the causative agent of bacterial spot disease in pepper and tomato plants, which leads to economically important yield losses. This pathosystem has become a well-established model for studying bacterial infection strategies. Here, we present the whole-genome sequence of the pepper-pathogenic Xanthomonas campestris pv. vesicatoria strain 85-10, which comprises a 5.17-Mb circular chromosome and four plasmids. The genome has a high G+C content (64.75%) and signatures of extensive genome plasticity. Whole-genome comparisons revealed a gene order similar to both Xanthomonas axonopodis pv. citri and Xanthomonas campestris pv. campestris and a structure completely different from Xanthomonas oryzae pv. oryzae. A total of 548 coding sequences (12.2%) are unique to X. campestris pv. vesicatoria. In addition to a type III secretion system, which is essential for pathogenicity, the genome of strain 85-10 encodes all other types of protein secretion systems described so far in gram-negative bacteria. Remarkably, one of the putative type IV secretion systems encoded on the largest plasmid is similar to the Icm/Dot systems of the human pathogens Legionella pneumophila and Coxiella burnetii. Comparisons with other completely sequenced plant pathogens predicted six novel type III effector proteins and several other virulence factors, including adhesins, cell wall-degrading enzymes, and extracellular polysaccharides.

Adhesins, Bacterial↗

PubMed1993

Serological differentiation between acute (late control) and endocarditis Q fever.

AIMS: To differentiate the serological profiles of chronic (endocarditis) Q fever from the late follow up of acute cases. METHODS: Twenty patients (10 diagnosed with acute and 10 with endocarditis Q fever) were studied. Those diagnosed with acute infection were followed up from 2.5 to 88 months (mean 35.8 months). Serological variables included indirect immunofluorescence against phase I and II of Coxiella burnetii (IgM, IgG, and IgA), complement fixation and rheumatoid factor (RF). RESULTS: All patients with titres of IgA against phase I, after IgG removal, equal to or above 320 and a complement fixation value equal to or above 128 had endocarditis. No patient with acute Q fever had such a serological profile. CONCLUSIONS: The combination of IgA against phase I and complement fixation values may be sufficient to differentiate the serological profile of chronic (endocarditis) Q fever from the late follow up of acute cases.

Acute Disease↗

PubMed1993

[Infectious endocarditis due to Q fever. A report of 4 new cases].

Q fever (Coxiella burnetii) is an uncommon cause of culture-negative infective endocarditis. Four cases of Q fever endocarditis diagnosed at our hospital in the last 7 years are reported (8% of all infective endocarditis). Infection involved a prosthetic heart valve in 3 cases (15% of all prosthetic valve endocarditis), and one patient with single ventricle and pulmonary stenosis in the remaining case. Important complications developed in all cases, and 3 patients underwent cardiac surgery. Mortality was 50%. Some diagnostic and therapeutical aspects of this disease are discussed.

Adult↗

PubMedDate not supplied

Q fever in Bulgaria and Slovakia.

As a result of dramatic political and economic changes in the beginning of the 1990s, Q-fever epidemiology in Bulgaria has changed. The number of goats almost tripled; contact between goat owners (and their families) and goats, as well as goats and other animals, increased; consumption of raw goat milk and its products increased; and goats replaced cattle and sheep as the main source of human Coxiella burnetii infections. Hundreds of overt, serologically confirmed human cases of acute Q fever have occurred. Chronic forms of Q fever manifesting as endocarditis were also observed. In contrast, in Slovakia, Q fever does not pose a serious public health problem, and the chronic form of infection has not been found either in follow-ups of a Q-fever epidemic connected with goats imported from Bulgaria and other previous Q-fever outbreaks or in a serologic survey. Serologic diagnosis as well as control and prevention of Q fever are discussed.

Animals↗

PubMed2002

Tularemia and Q fever.

The zoonotic infections caused by Francisella tularensis and Coxiella burnetii, tularemia and Q fever, respectively, are two less commonly encountered clinical illnesses that are becoming increasingly recognized as epidemiologically important human diseases. The prevalence of tularemia and Q fever can be positively impacted by increased awareness of the clinical entities that arise from infection by these arthropod-borne organisms. Improved recognition of these clinical syndromes will lead to greater diagnostic accuracy in recognizing these diseases in patients. Ultimately, more stringent measures to prevent infection may be required, through raising public awareness, since current therapeutic regimens for these two diseases are limited, and knowledge of the pathogenesis of these two organisms are still in developing stages.

Coxiella burnetii↗

PubMedDate not supplied

[The use of atomic-force microscopy for the analysis of microbiological objects].

Atomic force microscopy (AFM) was used for the analysis of rickettsiae and viruses. The specificity of interaction was evaluated on the basis of the adsorption of the analyzed antigen on the polymer-antibody film. The film was formed and transferred onto highly oriented pyrolytic graphite (HOPG) by the method of Langmuir-Schaefer with the use of amphiphilic polymers, alkylated polyethyleneimines. According to the data of AFM, polymer-antibody film was 10-30 nm thick and had ruptures, uneven surface. AFM images of Coxiella burnetii, rotavirus and Venezuelan equine encephalitis virus, immunoadsorbed on the antibody film, were obtained. C.burnetii, due to their size equal to (700-900) x (300-500) x Z = 200 nm, were clearly visible on the underlying surface and could be directly counted. Individual virus particles (60-80 nm) cold not be identified on such surface. To analyze such preparations, the program of image analysis was developed. The program classified the registered image with a certain standard. This program determined the presence of virus antigen on the underlying affinity surface with a high degree of precision.

Adsorption↗

PubMed1996

Autoimmune component in individuals during immune response to inactivated combined vaccine against Q fever.

Serum samples from 20 individuals immunized with inactivated combined vaccine (ICV) against Q fever and 10 individuals that received placebo were investigated on days 14, 21, 28 and 60 after immunization by isotope specific enzyme-linked immunosorbent assay (ELISA) for the presence of antibodies directed to human IgA, IgM and IgG, and their fragments (F(ab')2, Fab, Fc). None of the subjects that received placebo exhibited significant increase of reactivity with any of the used antigens. By contrast, the sera of immunized individuals tended to show increased autoantibody activity with diverse antigens. Forty % of sera of immunized subjects exhibited anti-Fab activity, 20% of the sera recognized IgA, F(ab')2- and Fc-fragments, and 15% of the sera recognized IgG and IgM. Although there was wide variation in antibody levels and in isotypic heterogeneity of autoantibodies induced by immunization, anti-Fab autoantibodies were represented mainly by IgG and IgA isotypes but not IgM isotype. A direct correlation between the anti-Coxiella burnetii (anti-C.b.) antibody level and the anti-Fab IgG activity, and between the anti-C.b. antibody level and the anti-Fab IgA activity was found. In the group of vaccinees reacting strongly to the vaccine against Q fever, this correlation significantly increased for both the anti-Fab IgG and the anti-Fab IgA activities. No correlation was found with the sera in the group of the subjects that received placebo.

Animals↗

PubMed2006

Multiplexed serology in atypical bacterial pneumonia.

Atypical pneumonia is a term applied to lower respiratory tract infections that are not characterized by signs and symptoms of lobar consolidation. This article will discuss the epidemiology, clinical manifestations, and laboratory diagnoses of Mycoplasma pneumoniae, Chlamydia sp., Legionella sp., Francisella tularensis, and Coxiella burnetii, which are the agents most commonly associated with atypical pneumonia. Because many of these pathogens are intracellular, diagnosis depends upon serological confirmation. The current serological tests used to identify these agents in the etiologic diagnosis of atypical pneumonia are described. Recently, however, it has become possible to make a diagnosis directly in these cases using DNA or protein microarrays. Here, we describe the development of a new, automated technique for simultaneous testing and detection of several pathogens using a multiplexed serology test. This should prove to be a valuable tool for the rapid determination of patient status, allowing effective and efficient postexposure prophylaxis and treatment.

Atypical Bacterial Forms↗

PubMed2006

Treatment of Chlamydia trachomatis with a small molecule inhibitor of the Yersinia type III secretion system disrupts progression of the chlamydial developmental cycle.

The obligate intracellular bacterium Chlamydia trachomatis possesses a biphasic developmental cycle that is manifested by differentiation of infectious, metabolically inert elementary bodies (EBs) to larger, metabolically active reticulate bodies (RBs). The cycle is completed by asynchronous differentiation of dividing RBs back to a population of dormant EBs that can initiate further rounds of infection upon lysis of the host cell. Chlamydiae express a type III secretion system (T3SS) that is presumably employed to establish and maintain the permissive intracellular niche by secretion of anti-host proteins. We hypothesize that T3SS activity is essential for chlamydial development and pathogenesis. However, the lack of a genetic system has confounded efforts to establish any role of the T3SS. We therefore employed the small molecule Yersinia T3SS inhibitor N'-(3,5-dibromo-2-hydroxybenzylidene)-4-nitrobenzohydrazide, designated compound 1 (C1), to examine the interdependence of the chlamydial T3SS and development. C1 treatment inhibited C. trachomatis but not T4SS-expressing Coxiella burnetii development in a dose-dependent manner. Although chlamydiae remained viable and metabolically active, they failed to divide significantly and RB to EB differentiation was inhibited. These effects occurred in the absence of host cell cytotoxicity and were reversible by washing out C1. We further demonstrate that secretion of T3S substrates is perturbed in C1-treated chlamydial cultures. We have therefore provided evidence that C1 can inhibit C. trachomatis development and T3SS activity and present a model in which progression of the C. trachomatis developmental cycle requires a fully functional T3SS.

Bacterial Proteins↗

PubMed1996

[Coronary-cardiac fistula as a cause of tricuspid endocarditis treated by mitral homograft].

The authors report a rare case which is interesting from three points of view: tricuspid valve endocarditis in a child complicating a fistula between the right coronary artery and right ventricle with negative blood cultures but a positive serology for Coxiella burnetii. This mutilating tricuspid endocarditis was complicated by multiple pulmonary embolism of the right lung. After two months of antibiotic therapy the coronaro-cardiac fistula was closed and the tricuspid valve replaced with a mitral homograft. All cases of blood culture negative endocarditis require serological investigation to detect intracellular organisms which are difficult to diagnose and justify specific prolonged antibiotic therapy. Control serological tests are essential in the long-term because of the risk of chronic infection, especially in cases with prosthetic intracardiac material. Treatment, based mainly on tetracyclines, should be continued for at least two years.

Anti-Bacterial Agents↗

PubMed1997

Acute Q fever as a cause of acute febrile illness of unknown origin in Taiwan: report of seven cases.

Acute Q fever, caused by Coxiella burnetii has been well documented in Western countries, but only recently identified in Taiwan. Seven cases diagnosed by indirect fluorescent antibodies to phase II antigens of C. burnetii are reported. The patients were all men and a history of animal contact could be traced in most cases. Clinical manifestations were high fever, chills, relative bradycardia and elevated serum aminotransferases. Therapy with tetracycline or clarithromycin resulted in defervescence within 96 hours. Combining the knowledge on the prevalence of Q fever in Taiwan, the typical exposure history and clinical features in acute Q fever infection, primary care physicians may be able to avoid invasive but futile diagnostic intervention for patients with prolonged febrile illness. Prior to results from serologic testing, empiric therapy with tetracycline or its analogs may be considered for patients with typical clinical manifestations.

Adult↗

PubMed1992

Phenotypic and genotypic heterogeneity of 8 new human Coxiella burnetti isolates.

Eight new strains of Coxiella burnetii were isolated from chronic Q fever patients using centrifugationashell vial technique. Seven patients had endocarditis (including one patient with an immunodeficiency syndrome), and one had a vascular prosthesis infection. Three prototype strains, Nine Mile phase II, Q212 and Priscilla and eight new isolates were cultured in L 929 cells. Heterogeneity of their cytopathic effect was observed. DNAs of the eleven strains have been isolated and purified by standard procedures. Plasmid DNA was separated from chromosomal DNA by a low melting point gel. Electrophoresis in agarose gel showed that seven of the eight new strains had plasmids which were about 40 kb (plasmid V517 was used as size marker). Endonuclease-restriction analysis of the 8 human isolates is currently under investigation.

Cells, Cultured↗

PubMed1996

Multiple pathogens in adult patients admitted with community-acquired pneumonia: a one year prospective study of 346 consecutive patients.

BACKGROUND: The purpose of this study was to assess the causes of community-acquired pneumonia in adult patients admitted to hospital. METHODS: A prospective study was performed on 346 consecutive adult patients (54% men) of mean (SD) 49.3 (19.5) years (range 17-94) admitted to a university affiliated regional hospital in southern Israel with community-acquired pneumonia over a period of one year. Convalescent serum samples were obtained from 308 patients (89%). The aetiological diagnosis for community-acquired pneumonia was based on positive blood cultures and/or significant changes in antibody titres to Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, respiratory viruses, Coxiella burnetii, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella sp. RESULTS: The aetiology of community-acquired pneumonia was identified in 279 patients (80.6%). The distribution of causal agents was as follows: S pneumoniae, 148 patients (42.8%); M pneumoniae, 101 (29.2%); C pneumoniae, 62 (17.9%); Legionella sp, 56 (16.2%); respiratory viruses, 35 (10.1%); C burnetii, 20 (5.8%); H influenzae 19 (5.5%); and other causes, 21 patients (6.0%). In patients above the age of 55 years C pneumoniae was the second most frequent aetiological agent (25.5%). In 133 patients (38.4%) more than one causal agent was found. CONCLUSIONS: The causal agents for community-acquired pneumonia in Israel are different from those described in other parts of the world. In many of the patients more than one causal agent was found. In all these patients treatment should include a macrolide antibiotic, at least in the first stage of their illness.

Adolescent↗

PubMed2006

[Q fever outbreak in an urban area following a school-farm visit].

BACKGROUND AND OBJECTIVE: The aim of this study was to describe an outbreak of Q fever in a group of people (day care centre for mental-handicapped individuals) previously exposed to animals in a school-farm. PATIENTS AND METHOD: A retrospective cohort study among the 25 mental-handicapped individuals and the 30 workers of the centre was performed. The information about symptoms and signs and antecedents of exposition was obtained by an epidemiological survey and a clinical-epidemiological case definition was established. Serum samples from 29 people (5 mental-handicapped individuals and 24 workers) were processed for serology (Indirect Immunofluorescence against Coxiella burnetii). RESULTS: Twenty two cases of Q fever were detected. Ten were confirmed by serology (6 of them asymptomatic). More frequent symptoms were fever (100%), anorexia (81.3%), asthenia (68.8%) and non-productive cough (56.3%) among the 16 clinical cases. The risk of acute infection was 8.6 times higher in individuals of the centre that visited the school-farm (95% CI, 1.26-58.27). CONCLUSIONS: The investigation of the epidemiological antecedents allowed to detect and confirm a Q fever outbreak, to identify the probable source of exposition and to orientate the clinical and serological diagnosis.

Adult↗

PubMed2006

Epidemiological study of Q fever in humans, ruminant animals, and ticks in Cyprus using a geographical information system.

A cross-sectional study of Q fever was conducted in a representative sample of the human and animal population in Cyprus in order to assess the seroprevalence of Q fever and the prevalence of related risk factors. A total of 583 human and 974 ruminant animal serum samples were collected and tested for the detection of antibodies against Coxiella burnetii phase II antigen using an indirect immunofluorescent assay. One hundred forty-one ticks were collected from the infested animals examined; the polymerase chain reaction and the shell-vial technique were used to detect and isolate C. burnetii. Standardized questionnaires were used to obtain information concerning inhabitants and their animals. A geographical information system was used to identify high-risk regions. The prevalence of IgG antibodies against C. burnetii phase II antigen was estimated at 52.7% for humans, 48.2% for goats, 18.9% for sheep, and 24% for bovines. C. burnetii was detected in 11 (7.8%) ticks. Using the geographical information system, two villages were identified as high-risk regions on the basis of high seroprevalence rates of IgG antibodies in humans and animals. Risk factors related to Q fever seropositivity were identified by logistic regression analysis and included age, residence, occupation, use of manure in the garden, ownership of animals (especially goats), and the presence of tick-infested or aborting animals. Q fever poses an occupational hazard to humans living in close contact with sheep and/or goats. In parallel, ticks should be considered an important aspect in the epidemiology of Q fever and should be further studied to better elucidate their role.

Adolescent↗

PubMed2000

Seroprevalence of antibodies to Coxiella burnetti among pregnant women in South Eastern France.

OBJECTIVES: To estimate the seroprevalence of antibodies to Coxiella burnetii among pregnant women and to assess the effect of Q fever on pregnancy outcome. STUDY DESIGN: Anonymous seroprevalence survey between March and May 1996 in all gynecological and obstetrical medical departments of South Eastern France. Women were included irrespective of pregnancy outcome (N=12,716, response rate=96.1%). RESULTS: The seroprevalence rate was 0.15% with a global prevalence and a prevalence of recent or chronic infections, respectively, two and three times higher among women who had a spontaneous abortion than among those who delivered although the differences were not statistically significant. The highest proportion of preterm births (6.8%) was found in high prevalence areas (0.57%). CONCLUSION: The seroprevalence was higher than expected but data were not sufficient to confirm the suspected negative impact of Q fever on pregnancy outcome.

Abortion, Spontaneous↗