Deciphering Unexpected Vascular Locations of Scedosporium spp. and Lomentospora prolificans Fungal Infections, France

Scedosporium spp. and Lomentospora prolificans are emerging non-Aspergillus filamentous fungi. The Scedosporiosis/lomentosporiosis Observational Study we previously conducted reported frequent fungal vascular involvement, including aortitis and peripheral arteritis. For this article, we reviewed 7 cases of Scedosporium spp. and L. prolificans arteritis from the Scedosporiosis/lomentosporiosis Observational Study and 13 cases from published literature. Underlying immunosuppression was reported in 70% (14/20) of case-patients, mainly those who had solid organ transplants (10/14). Osteoarticular localization of infection was observed in 50% (10/20) of cases; infections were frequently (7/10) contiguous with vascular infection sites. Scedosporium spp./Lomentospora prolificans infections were diagnosed in 9 of 20 patients ≈3 months after completing treatment for nonvascular scedosporiosis/lomentosporiosis. Aneurysms were found in 8/11 aortitis and 6/10 peripheral arteritis cases. Invasive fungal disease--related deaths were high (12/18 [67%]). The vascular tropism of Scedosporium spp. and L. prolificans indicates vascular imaging, such as computed tomography angiography, is needed to manage infections, especially for osteoarticular locations.

An ex vivo study of infections of vascular grafts and endografts with scanning electron microscopy

BACKGROUND

Vascular graft and endograft infections (VGEIs) are complicated by high morbidity, mortality, and recurrence rates, notably due to biofilm formation on the graft surface, hardly dislodgeable by the sole anti-infectious treatment. The characteristics of this biofilm are still poorly documented. The aim of this study was to evaluate ex vivo biofilm on removed infected vascular grafts and endografts (VGEs).

METHODS

Explanted VGEs were prospectively collected from 2019 to 2022 at Bordeaux University Hospital, France. Two samples per graft were used for scanning electron microscopy imaging, one was sonicated and both grafts' sides were imaged.

RESULTS

A total of 26 patients were included, 18 with VGEI, eight without any infection (endoleak and/or thrombosis) and 29 VGEs were collected. Microbial documentation was obtained in 83% of VGEIs. A thick layer of fibrin was visible on almost all grafts, mixed with a dense biofilm matrix on infected grafts visible as early as one month after the onset of infection. Bacteria were not always visualized on infected grafts' surface (80% on outer side and 85% on luminal side) but were surprisingly present on a third of non-infected grafts. There was no significant difference between biofilm, fibrin, and microorganisms' distribution between the two grafts' sides. However, there were clear differences between infected and non-infected grafts, since immune cells, bacteria and biofilm were more frequently visualized on both sides of infected grafts (p<.05). Bacteria and immune cells although still visible, were significantly less present after sonication; the number of other elements including biofilm was not significantly different.

CONCLUSIONS

The persistence of a thick layer of fibrin and biofilm embedding microorganisms on both sides of infected VGE even after one month of infection could be the explanation for the low success rates of conservative management and the usual need for graft removal to treat VGEIs.

Retrospective Multicenter Study Comparing Infectious and Noninfectious Aortitis

BACKGROUND

Determining the etiology of aortitis is often challenging, in particular to distinguish infectious aortitis (IA) and noninfectious aortitis (NIA). This study aims to describe and compare the clinical, biological, and radiological characteristics of IA and NIA and their outcomes.

METHODS

A multicenter retrospective study was performed in 10 French centers, including patients with aortitis between 1 January 2014 and 31 December 2019.

RESULTS

One hundred eighty-three patients were included. Of these, 66 had IA (36.1%); the causative organism was Enterobacterales and streptococci in 18.2% each, Staphylococcus aureus in 13.6%, and Coxiella burnetii in 10.6%. NIA was diagnosed in 117 patients (63.9%), mainly due to vasculitides (49.6%), followed by idiopathic aortitis (39.3%). IA was more frequently associated with aortic aneurysms compared with NIA (78.8% vs 17.6%, P < .001), especially located in the abdominal aorta (69.7% vs 23.1%, P < .001). Crude and adjusted survival were significantly lower in IA compared to NIA (P < .001 and P = .006, respectively). In the IA cohort, high American Society of Anesthesiologists score (hazard ratio [HR], 2.47 [95% confidence interval {CI}, 1.08-5.66]; P = .033) and free aneurysm rupture (HR, 9.54 [95% CI, 1.04-87.11]; P = .046) were significantly associated with mortality after adjusting for age, sex, and Charlson comorbidity score. Effective empiric antimicrobial therapy, initiated before any microbial documentation, was associated with a decreased mortality (HR, 0.23, 95% CI, .08-.71]; P = .01).

CONCLUSIONS

IA was complicated by significantly higher mortality rates compared with NIA. An appropriate initial antibiotic therapy appeared as a protective factor in IA.

Using a population-based Kalman estimator to model the COVID-19 epidemic in France: estimating associations between disease transmission and non-pharmaceutical interventions

In response to the COVID-19 pandemic caused by SARS-CoV-2, governments have adopted a wide range of non-pharmaceutical interventions (NPI). These include stringent measures such as strict lockdowns, closing schools, bars and restaurants, curfews, and barrier gestures such as mask-wearing and social distancing. Deciphering the effectiveness of each NPI is critical to responding to future waves and outbreaks. To this end, we first develop a dynamic model of the French COVID-19 epidemics over a one-year period. We rely on a global extended Susceptible-Infectious-Recovered (SIR) mechanistic model of infection that includes a dynamic transmission rate over time. Multilevel data across French regions are integrated using random effects on the parameters of the mechanistic model, boosting statistical power by multiplying integrated observation series. We estimate the parameters using a new population-based statistical approach based on a Kalman filter, used for the first time in analysing real-world data. We then fit the estimated time-varying transmission rate using a regression model that depends on the NPIs while accounting for vaccination coverage, the occurrence of variants of concern (VoC), and seasonal weather conditions. We show that all NPIs considered have an independent significant association with transmission rates. In addition, we show a strong association between weather conditions that reduces transmission in summer, and we also estimate increased transmissibility of VoC.

P306 Scedosporium spp. and Lomentospora prolificans, fungal agents with unexpected vascular tropism

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM

 

Objectives

Invasive scedosporiosis and lomentosporiosis are deadly fungal infections due to Scedosporium spp. and Lomentospora prolificans. The Scedosporiosis/lomentosporiosis Observational Study (S.O.S.) highlighted for the first time a frequent vascular involvement in these infections including aortitis and peripheral arteritis (PA). We here describe the clinical, microbiological, radiological and anatomopathological characteristics of these vascular infections.

Methods

We retrospectively reviewed cases of arteritis (with the exception of central nervous system arteritis) from the S.O.S. cohort and from the literature.

Results

Seven cases of vascular infections were identified from the S.O.S. cohort representing 24% (7/29) of the disseminated scedosporiosis/lomentosporiosis. Four cases had both aortitis and PA, 2 patients were diagnosed with PA and one patient with aortitis. A total of 9 aortitis and 4 PA cases were identified from the literature. All 20 cases were proven scedosporiosis/lomentosporiosis. The main species was S. apiospermum [60% of cases (12/20)] followed by L. prolificans [35% of cases (7/20)]. One infection was caused by both species. An underlying immunosuppression was present in 70% of the cases (14/20, with 10 cases of solid organ transplantation and 3 cases of hematologic malignancies). The main risk factor in immunocompetent patients was a previous cutaneous trauma (4/6). Interestingly, vascular involvement was identified at diagnosis of the scedosporiosis/lomentosporiosis in only half of the cases. Aortitis was mainly abdominal (8/13). Various PA localizations were reported with frequent iliac or femoral involvement (4/10). Arteritis was the only localization in only 10% (2/20) of the scedosporiosis/lomentosporiosis, other sites involved being mainly osteoarticular (10/20), and pulmonary (9/20) followed by central nervous system (5/20), cutaneous localizations (4/20), and endocarditis (4/20). Of note, three-quarters of the cases were disseminated. Aneurysmal lesion was the most frequent imaging aspect (8/11 of aortitis and 6/10 of PA) which was complicated by a rupture in half of the aortitis (4/8) and only one PA (1/6). Vascular wall thickening (2/11 of aortitis and 1/10 of PA) and perivascular abscess (1/11 and 1/10, respectively) were more rarely described. Hypermetabolism was constant on PET-CT scan when performed (6/6). When available (11/20), pathological analysis showed an invasion of the artery wall by fungal hyphae (10/11), particularly in the media and the adventice. A total of 3-months of mortality related to infection was 44% (8/18), rising to 71% (5/7) in case of fungemia.

Conclusion

The vascular tropism of Scedosporium spp. and L. prolificans underlies the necessity of vascular imaging in the management of these infections, especially in case of dissemination seeking in particular aneurysmal lesions of the abdominal aorta and iliofemoral arteries.