Q fever in pregnancy: case report after a 2-year follow-up

Infection and Persistence of Coxiella burnetii Clinical Isolate in the Placental Environment

Infection by Coxiella burnetii, the etiological agent of Q fever, poses the risk of causing severe obstetrical complications in pregnant women. C. burnetii is known for its placental tropism based on animal models of infection. The Nine Mile strain has been mostly used to study C. burnetii pathogenicity but the contribution of human isolates to C. burnetii pathogenicity is poorly understood. In this study, we compared five C. burnetii isolates from human placentas with C. burnetii strains including Nine Mile (NM) as reference. Comparative genomic analysis revealed that the Cb122 isolate was distinct from other placental isolates and the C. burnetii NM strain with a set of unique genes involved in energy generation and a type 1 secretion system. The infection of Balb/C mice with the Cb122 isolate showed higher virulence than that of NM or other placental isolates. We evaluated the pathogenicity of the Cb122 isolate by in vitro and ex vivo experiments. As C. burnetii is known to infect and survive within macrophages, we isolated monocytes and placental macrophages from healthy donors and infected them with the Cb122 isolate and the reference strain. We showed that bacteria from the Cb122 isolate were less internalized by monocyte-derived macrophages (MDM) than NM bacteria but the reference strain and the Cb122 isolate were similarly internalized by placental macrophages. The Cb122 isolate and the reference strain survived similarly in the two macrophage types. While the Cb122 isolate and the NM strain stimulated a poorly inflammatory program in MDM, they elicited an inflammatory program in placenta macrophages. We also reported that the Cb122 isolate and NM strain were internalized by trophoblastic cell lines and primary trophoblasts without specific replicative profiles. Placental explants were then infected with the Cb122 isolate and the NM strain. The bacteria from the Cb122 isolate were enriched in the chorionic villous foetal side. It is likely that the Cb122 isolate exhibited increased virulence in the multicellular environment provided by explants. Taken together, these results showed that the placental isolate of C. burnetii exhibits a specific infectious profile but its pathogenic role is not as high as the host immune response in pregnant women.

From Coxiella burnetii Infection to Pregnancy Complications: Key Role of the Immune Response of Placental Cells

The infection of pregnant animals and women by Coxiella burnetii, an intracellular bacterium, compromises both maternal health and foetal development. The placenta is targeted by C. burnetii, as demonstrated by bacteriological and histological evidence. It now appears that placental strains of C. burnetii are highly virulent compared to reference strains and that placental injury involves different types of placental cells. Trophoblasts, the major placental cells, are largely infected by C. burnetii and may represent a replicating niche for the bacteria. The placenta also contains numerous immune cells, including macrophages, dendritic cells, and mast cells. Placental macrophages are infected and activated by C. burnetii in an unusual way of M1 polarisation associated with bacterial elimination. Placental mast cells eliminate bacteria through a mechanism including the release of extracellular actin filaments and antimicrobial peptides. In contrast, C. burnetii impairs the maturation of decidual dendritic cells, favouring bacterial pathogenicity. Our aim is to review C. burnetii infections of human placentas, paying special attention to both the action and function of the different cell types, immune cells, and trophoblasts targeted by C. burnetii in relation to foetal injury.

Pediatric acute Q fever mimics other common childhood illnesses

Knowledge of Q fever has increased over the last decades, but research has mainly focused on adults. Data in children are scarce, and current knowledge is mostly based on case reports. The aim of this study was to determine predictors for acute Q fever in children in the general population. We retrospectively studied all children tested for Coxiella burnetii by serology and/or PCR upon request of their general practitioner in the regional laboratory for Medical Microbiology of the Jeroen Bosch during the Q fever outbreak in the Netherlands between 2007 and 2011. A total of 1061 patients was analyzed. Influenza-like illness and respiratory tract infection were the most common presentations of acute Q fever, mimicking other common childhood illnesses. None of the reported symptoms was significantly related to a positive test outcome and therefore presenting signs or symptoms have no predictive value in diagnosing Q-fever in children. Only diagnostic tests are reliable. As the infection generally follows a mild and uncomplicated course, we question if the difficulty of recognizing pediatric Q fever is a problem worth solving.

Q fever and pregnancy: disease, prevention, and strain specificity

The link between fetal morbidity and Q fever and the necessity of long-term antibiotics for Coxiella burnetii infection during pregnancy have been recently questioned in the Netherlands, where the clone responsible for the Q fever outbreak harbors the QpH1 plasmid. In this context, we assessed pregnancy outcomes according to antibiotic administration in a new series and compared the plasmid type between isolates associated with abortion and other clinical isolates to determine if there is a link between genotype and abortion in humans. All French patients who received a diagnosis of Q fever during pregnancy at the French National Referral Centre for Q Fever from 2006 through July 2011 were included. On the other hand, the plasmid types of 160 clinical isolates, including seven isolates from patients who experienced an abortion, were compared. The differences between the QpDV and QpH1 plasmid sequences were analyzed. Acute Q fever was a cause of fetal morbidity, and the absence of long-term cotrimoxazole therapy was associated with fetal death (p < 0.0001). Genotypic analysis showed that the QpDV plasmid was more frequent in isolates associated with abortion (p = 0.03). A comparison of the plasmid sequences revealed that four QpDV proteins had no direct counterparts in QpH1, with two whose functions were not present in QpH1. The different obstetrical morbidity of C. burnetii relative to different geographical areas could be related to strain specificity, possibly based on differences in plasmid sequences, or to a failure of public health authorities to detect early miscarriages.

Q Fever during pregnancy: a cause of poor fetal and maternal outcome

Q fever is a worldwide zoonosis caused by Coxiella burnetii. Q fever may be present as an acute or a chronic infection and can be reactivated during subsequent pregnancies. Although its exact prevalence remains unknown, it is likely that the number of cases of Q fever in pregnant women is underestimated. During pregnancy, the illness is likely to be asymptomatic, and diagnosis is based on serology. Acute infection results in appearance of IgM and IgG antibodies mainly directed against the avirulent form of C. burnetii (phase II). Chronic Q fever results in particularly high level of IgG and IgA antibodies directed against both virulent (phase I) and avirulent (phase II) forms of the bacterium. Q fever may result in adverse pregnancy outcome, including spontaneous abortion, intrauterine growth retardation, oligoamnios, intrauterine fetal death (IUFD), and premature delivery. Obstetric complications occur significantly more often as C. burnetii infects the patient at an early stage of her pregnancy. Occurrence of IUFD is correlated with the presence of placental infection by C. burnetii and might be the consequence of direct infection of the fetus. The mother is exposed to the risk of chronic Q fever and endocarditis with potential fatal evolution. Long-term cotrimoxazole therapy prevents from placental infection, IUFD, and maternal chronic Q fever. Such treatment should be used to treat pregnant women with Q fever. Women with previous history of Q fever should have a regular serological follow up. Obstetricians' knowledge about Q fever must be improved.

Managing Q fever during pregnancy: the benefits of long-term cotrimoxazole therapy

BACKGROUND

Q fever is a zoonosis caused by Coxiella burnetii. During pregnancy, it may result in obstetric complications, such as spontaneous abortion, intrauterine growth retardation, intrauterine fetal death, and premature delivery. Pregnant women are exposed to the risk of chronic Q fever.

METHODS

We included 53 pregnant women who received a diagnosis of Q fever. We compared the incidence of obstetric and maternal Q fever complications for women who received long-term cotrimoxazole treatment (n=16) with that for women who did not receive long-term cotrimoxazole treatment (n=37); long-term cotrimoxazole treatment was defined as oral administration of trimethoprim-sulfamethoxazole during at least 5 weeks of pregnancy.

RESULTS

Obstetric complications were observed in 81.1% of pregnant women who did not receive long-term cotrimoxazole therapy: 5 (13.5%) women experienced spontaneous abortions, 10 (27%) experienced intrauterine growth retardation, 10 (27%) experienced intrauterine fetal death, and 10 (27%) experienced premature delivery. Oligoamnios was observed in 4 patients (10.8%). Obstetric complications were found to occur significantly more often in patients infected during their first trimester of pregnancy than in those infected later (P=.032). The outcome of the pregnancy was found to depend on placental infection by C. burnetii (P=.013). Long-term cotrimoxazole treatment protected against maternal chronic Q fever (P=.001), placental infection (P=.038), and obstetric complications (P=.009), especially intrauterine fetal death (P=.018), which was found to be related to placental infection (P=.008).

CONCLUSIONS

Q fever during pregnancy results in severe obstetric complications, including oligoamnios. Because of its ability to protect against placental infection, intrauterine fetal death, and maternal chronic Q fever, long-term cotrimoxazole treatment should be used to treat pregnant women with Q fever.

A seroepidemiological study of the risks of Q fever infection in Japanese veterinarians

The causative agent of Q fever, a widespread zoonotic disease, is the bacteria Coxiella burnetii. Although cases of Q fever have been documented in countries throughout the world, the prevalence of the disease in Japan is not yet known. Q fever is a demonstrated occupational hazard to those employed in zoological professions, but the risk to Japanese veterinarians has not yet been quantified. In order to evaluate the risk to Japanese veterinarians, we performed a serological survey using serum samples from 267 veterinarians. Two control groups consisting of 352 medical workers and 2003 healthy blood donors were also evaluated. The antibody titers of the serum samples were measured by indirect immunofluorescence assay (IFA) using phase II C. burnetii Nine Mile strain as the antigen. The positive rate of IgG antibody was 13.5% in the veterinarians, which was higher than in the blood donors (3.6%, p < 0.001) and medical workers (5.1 %,p < 0.001). These findings suggest that Japanese veterinarians have a higher risk of infection by C. burnetii than other members of the Japanese population. An interesting finding of this study was that positive rates of IgG and IgM antibodies in the blood donor group were higher in younger individuals. The IgM antibody positive rate was the highest in females under 30 years old.

Q fever during pregnancy: an emerging cause of prematurity and abortion

Background: Although the pathogenic role of Coxiella burnetii infection during pregnancy is controversial, some cases of stillbirth and abortion occurring after an acute or chronic infection have been mentioned in the literature. Recently, Q fever has been advocated as a significant cause of morbidity and mortality in pregnancy

Case: We describe an 18-year-old primipara woman admitted to our hospital for high fever and pancytopenia during an acute C. burnetii infection. She was successfully treated with clarithromycin, overcoming fever and pancytopenia. Finally, she gave birth to a healthy infant, and 1 year later both remained well.

Conclusion: Q fever is a potentially serious disease in pregnancy owing to the possibility of placenta infection and fetal transmission affecting its outcome. Q fever infection should be suspected in unexplained febrile episodes or abortion during pregnancy, when epidemiologic and clinical data are present.We believe that C. burnetii serology should be tested in cases of fever of known origin or unexplained abortions, as the TORCH infections are.