Carole Eldin

Coxiella burnetii DNA, But Not Viable Bacteria, in Dairy Products in France

Transmission by the oral route of Coxiella burnetii is controversial. Our objective was to evaluate dairy products in the transmission of Q fever. Pasteurized, unpasteurized, and thermized dairy products were tested for C. burnetii by using a quantitative polymerase chain reaction specific for IS1111 and IS30A spacers, culturing in human embryonic lung fibroblasts cells, and inoculation into BALB/c mice. We tested 201 products and C. burnetii was identified in 64%. Cow milk origin products were more frequently positive than goat or ewe products (P = 0.006 and P = 0.0001, respectively), and industrial food was more frequently positive than artisanal food (P < 0.0001). Food made from unpasteurized milk contained higher bacteria concentrations than food made from pasteurized milk (P = 0.02). All cultures were negative and mice did not show signs of illness. Farm animals are highly infected in France but consumption of cheese and yogurt does not seem to pose a public health risk for transmission of Q fever.

Q Fever in French Guiana

Coxiella burnetii, the causative agent of Q fever, is present worldwide. Recent studies have shown that this bacterium is an emerging pathogen in French Guiana and has a high prevalence (24% of community-acquired pneumonia). In this review, we focus on the peculiar epidemiology of Q fever in French Guiana. We place it in the context of the epidemiology of the disease in the surrounding countries of South America. We also review the clinical features of Q fever in this region, which has severe initial presentation but low mortality rates. These characteristics seem to be linked to a unique genotype (genotype 17). Finally, we discuss the issue of the animal reservoir of C. burnetii in French Guiana, which is still unknown. Further studies are necessary to identify this reservoir. Identification of this reservoir will improve the understanding of the Q fever epidemic in French Guiana and will provide new tools to control this public health problem.

Emergence of Rickettsia africae , Oceania

We detected Rickettsia africae, the agent of African tick-bite fever (ATBF), by amplification of fragments of gltA, ompA, and ompB genes from 3 specimens of Amblyomma loculosum ticks collected from humans and birds in New Caledonia. Clinicians who treat persons in this region should be on alert for ATBF.

Loss of TSS1 in hypervirulent Coxiella burnetii 175, the causative agent of Q fever in French Guiana

In French Guiana, the unique Coxiella burnetii circulating genotype 17 causes 24% of community-acquired pneumonia, the highest prevalence ever described. To explain this unusual virulence, we performed a comparative genomic analysis of strain Cb175, which was isolated from a patient from French Guiana. Cb175 has a greater number of mutations in genes involved in metabolism compared with the Nine Mile I strain. We found a 6105bp fragment missing in Cb175, which corresponds to the Type 1 secretion systems (T1SS) hlyCABD operon region. This deletion was detected by a specific qPCR in the 8 other strains available from this territory an in none of 298C.burnetii strains from other areas and other genotypes (8/8 vs 0/298, Fishers exact test, p<0.0000001). Loss of genes implicated in secretion systems has been observed in other epidemic bacterial strains. Thus, the virulence of Cb175 may be linked to this genome reduction.

Cell Extract-Containing Medium for Culture of Intracellular Fastidious Bacteria

ABSTRACT The culture of fastidious microorganisms is a critical step in infectious disease studies. As a proof-of-concept experiment, we evaluated an empirical medium containing eukaryotic cell extracts for its ability to support the growth of Coxiella burnetii. Here, we demonstrate the exponential growth of several bacterial strains, including the C. burnetii Nine Mile phase I and phase II strains, and C. burnetii isolates from humans and animals. Low-oxygen-tension conditions and the presence of small hydrophilic molecules and short peptides were critical for facilitating growth. Moreover, bacterial antigenicity was conserved, revealing the potential for this culture medium to be used in diagnostic tests and in the elaboration of vaccines against C. burnetii. We were also able to grow the majority of previously tested intracellular and fastidious bacterial species, including Tropheryma whipplei, Mycobacterium bovis, Leptospira spp., Borrelia spp., and most putative bioterrorism agents. However, we were unable to culture Rickettsia africae and Legionella spp. in this medium. The versatility of this medium should encourage its use as a replacement for the cell-based culture systems currently used for growing several facultative and putative intracellular bacterial species.

Treatment and Prophylactic Strategy for Coxiella burnetii Infection of Aneurysms and Vascular Grafts: A Retrospective Cohort Study

AbstractCoxiella burnetii vascular infections continue to be very severe diseases and no guidelines exist about their prevention. In terms of treatment, the benefit of the surgical removal of infected tissues has been suggested by 1 retrospective study.We present a case of a C burnetii abdominal aortic graft infection for which we observed a dramatic clinical and biological recovery after surgery. We thus performed a retrospective cohort study to evaluate the impact of surgery on survival and serological outcome for patients with Q fever vascular infections diagnosed in our center.Between 1986 and February 2015, 100 patients were diagnosed with Q fever vascular infections. The incidence of these infections has significantly increased over the past 5 years, in comparison with the mean annual incidence over the preceding 22 years (8.83 cases per year versus 3.14 cases per year, P = 0.001). A two-and-a-half-year follow-up was available for 66 patients, of whom 18.2% died. We observed 6.5% of deaths in the group of patients who were operated upon at 2 and a half years, in comparison with 28.6% in the group which were not operated upon (P = 0.02). Surgery was the only factor that had a positive impact on survival at 2 and a half years using univariate analysis [hazard ratio: 0.17 [95% CI]: [0.039–0.79]; P = 0.024]. Surgery was also associated with a good serological outcome (74.1% vs 57.1% of patients, P = 0.03). In the group of patients with vascular graft infections (n = 47), surgery had a positive impact on serological outcome at 2 and a half years (85.7% vs 42.9%, P < 0.001) [hazard ratio: 0.40 [95% CI]: [0.17–098]; P = 0.046] and tended to be associated with lower although not statistically significant mortality (11.1% vs 27.6% of deaths, P = 0.19).Surgical treatment confers a benefit in terms of survival following C burnetii vascular infections. However, given the high mortality of these infections and their rising incidence, we propose a strategy that consists of screening for vascular graft and aneurysms in the context of primary Q fever, to decide when to start prophylactic treatment, similar to the strategy recommended for the prophylaxis of Q fever endocarditis.

18F-FDG PET/CT as a central tool in the shift from chronic Q fever to Coxiella burnetii persistent focalized infection: A consecutive case series.

AbstractBecause Q fever is mostly diagnosed serologically, localizing a persistent focus of Coxiella burnetii infection can be challenging. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) could be an interesting tool in this context.We performed a retrospective study on patients diagnosed with C burnetii infection, who had undergone 18F-FDG PET/CT between 2009 and 2015. When positive 18F-FDG PET/CT results were obtained, we tried to determine if it changed the previous diagnosis by discovering or confirming a suspected focus of C burnetii infection.One hundred sixty-seven patients benefited from 18F-FDG PET/CT. The most frequent clinical subgroup before 18F-FDG PET/CT was patients with no identified focus of infection, despite high IgG1 serological titers (34%). For 59% (n = 99) of patients, a hypermetabolic focus was identified. For 62 patients (62.6%), the positive 18F-FDG PET/CT allowed the diagnosis to be changed. For 24 of them, (38.7%), a previously unsuspected focus of infection was discovered. Forty-two (42%) positive patients had more than 1 hypermetabolic focus. We observed 21 valvular foci, 34 vascular foci, and a high proportion of osteoarticular localizations (n = 21). We also observed lymphadenitis (n = 27), bone marrow hypermetabolism (n = 11), and 9 pulmonary localizations.We confirmed that18F-FDG PET/CT is a central tool in the diagnosis of C burnetii focalized persistent infection. We proposed new diagnostic scores for 2 main clinical entities identified using 18F-FDG PET/CT: osteoarticular persistent infections and lymphadenitis.

Early Fecal Microbiota Transplantation Improves Survival in Severe Clostridium difficile Infections

Background Severe Clostridium difficile infections (CDIs) are associated with a high mortality rate despite medical and/or surgical treatment. Fecal microbiota transplantation (FMT) prevents recurrences, but its effect on survival has been shown only in patients with O27 ribotype CDI. Here, we investigated whether early FMT could improve survival in hospitalized CDI patients, particularly those with severe infection. Methods We performed a retrospective cohort study between May 2013 and April 2016 at the infectious diseases department of the North University Hospital of Marseille, France. Patients received either medical treatment alone or treatment with early FMT. The primary outcome was the 3-month mortality rate. Results A total of 111 patients were included: 66 in the FMT group and 45 in the non-FMT group. No patient underwent surgery. The O27 ribotype (odds ratio [OR], 3.64 [95% confidence interval {CI}, 1.05- 12.6], P = .04), severe CDI (OR, 9.62 [95% CI, 2.16-42.8], P = .003), and FMT (OR, 0.13 [95% CI, .04-.44], P = .001) were independent predictors of 3-month mortality. FMT improved survival in severe cases (OR, 0.08 [95% CI, .016-.34], P = .001) but not in nonsevere cases (OR, 1.07 [95% CI, .02-56.3], P = .97), independent of age, sex, comorbidities (Charlson score), and ribotype. The number of severe patients who needed to be treated to save 1 life at 3 months was 2. Conclusions Early FMT dramatically reduces mortality and should be proposed as a first-line treatment for severe CDI. Further studies are needed to clarify complications and contraindications. Surgery should be reassessed in this context.

The contribution of genomics to the study of Q fever

Coxiella burnetii is the etiological agent of Q fever, a worldwide zoonosis that can result in large outbreaks. The birth of genomics and sequencing of C. burnetii strains has revolutionized many fields of study of this infection. Accurate genotyping methods and comparative genomic analysis have enabled description of the diversity of strains around the world and their link with pathogenicity. Genomics has also permitted the development of qPCR tools and axenic culture medium, facilitating the diagnosis of Q fever. Moreover, several pathophysiological mechanisms can now be predicted and therapeutic strategies can be determined thanks to in silico genome analysis. An extensive pan-genomic analysis will allow for a comprehensive view of the clonal diversity of C. burnetii and its link with virulence.

Identification of dengue type 2 virus in febrile travellers returning from Burkina Faso to France, related to an ongoing outbreak, October to November 2016

Dengue fever is rarely reported in travellers returning from Africa. We report two cases of dengue fever in travellers returning from Burkina Faso to France. One of them presented a severe dengue fever with ALT > 1,000 IU/L and pericarditis. Serotype 2 was identified. The cases reflect a large ongoing outbreak with over 1,000 reported cases between August and November in the capital city. Clinicians should consider dengue fever in malaria-negative febrile travellers returning from Africa.