ALBERT

Description: Despite Aspergillus being the leading cause of exogenous fungal endophthalmitis following traumatic injury to the eye, its pathogenesis is not fully understood. In the current study, we developed a murine model of Aspergillus fumigatus (AF) endophthalmitis and investigated the disease pathobiology. Endophthalmitis was induced by intravitreal injection of Aspergillus spores in immunocompetent and immunocompromised (neutropenic) C57BL/6 mice, and disease severity was assessed by eye exam, fungal burden estimation, and histological examination. Our data showed that AF infection caused a time-dependent increase in corneal haze, opacity, and hypopyon beginning at two days post-infection (DPI). The fungal burden in infected eyes of immunocompetent mice peaked at 2 DPI and declined over 9 DPI. AF-infected neuroretina exhibited induction of innate immune response via upregulation of Toll-like receptors (TLRs) and inflammatory mediators (TNFα, IL-1β, and IL6), and increased polymorphonuclear neutrophil (PMN) infiltration. Histological analysis revealed heavy cellular infiltrates in the vitreous cavity as well as disruption of normal retinal architecture and increased retinal cell death. Neutropenic mice exhibited severe disease pathology with the prolonged fungal burden and increased inflammatory mediators. Our study described the first immunocompetent murine model of exogenous AF endophthalmitis and demonstrated an important role of neutrophils in innate defense against fungal endophthalmitis.

Description: Background Clostridium difficile (CD) is the leading cause of nosocomial diarrhea. After acquisition of CD, some patients (pts) remain colonized whereas others develop symptomatic CD infection (CDI). Hematopoietic stem cell transplant (HSCT) recipients are at higher risk of CDI than the general population. Rates of colonization and risk factors for CD colonization in the HSCT population are unknown. The goals of this study were to determine the rates and predictors of colonization with CD in HSCT pts at our institution. Methods We conducted a 16-month prospective study starting in December 2010 in the HSCT unit at the Karmanos Cancer Center. Pts who signed informed consent had stool samples collected within 72 hours of admission and weekly thereafter until discharge. Pts were followed up for 90 days after enrollment. Stool samples were cultured for CD and culture positive samples were tested by PCR for confirmation of toxigenic CD. Demographic information, risk factors and outcomes were examined. Results 154 patients who underwent allogeneic HSCT were enrolled in the study. Mean age for both CD colonized and non-colonized pts was 51 ±12.8 years, 59% were males. Overall, 47/154 (30%) pts were colonized with CD at admission; 23/154 (15%) with toxigenic CD. 8/23 (34%) pts colonized with toxigenic CD developed symptomatic CDI. Of the pts colonized with non-toxigenic CD, 7/24 (29%) acquired CD during the hospital stay. The median time to acquisition was week 2 of hospitalization. On bivariate analysis, underlying comorbid conditions and traditional risk factors for CDI like prior hospitalization, length-of-stay, antibiotic use, nasogastric tube and gastrointestinal tract procedures were found to be equally prevalent in both colonized and non-colonized population. The outcome in terms of graft versus host disease (GVHD) was also similar in both groups. The use of proton pump inhibitors was more prevalent in non-colonizers (56%) vs. colonizers (43%). However, it was not statistically significant (p=0.16). Similarly, lymphopenia seemed common amongst colonizers vs. non-colonizers (67% vs. 58%) but was not statistically significant (p=0.2). Conclusion Colonization with toxigenic CD is high in our HSCT recipients at hospital admission. Symptomatic CDI occurs in a third of pts colonized with toxigenic CD. Unlike in the general population, traditional risk factors for CD colonization are not predictive of colonization in our allogeneic HSCT pts. Novel approaches such as active surveillance to detect colonized patients to guide infection control measures and to direct “pre-emptive” therapy should be evaluated in this population. Disclosures: No relevant conflicts of interest to declare.

Description: Introduction: Clostridium difficile (C.diff) colitis (CDI) continues to be a common complication in recipients of allogeneic stem cell transplantation (AlloSCT). Multiple risk factors were associated with CDI in this patient population including prior CDI, antibiotic prophylaxis and therapy, acute graft versus host disease (aGVHD), etc. Our aim in this study was to evaluate the effect of thymoglobulin used in GVHD prophylaxis on the incidence of CDI in patients undergoing AlloSCT. Methods: We studied 3 consecutive cohorts of AlloSCT recipients. Group1- related donor AlloSCT without thymoglobulin (N=100, transplanted 3/2010-12/2013); group 2 - unrelated donor AlloSCT with thymoglobulin (N=110, transplanted 4/2012-12/2013); and group 3 - unrelated AlloSCT without thymoglobulin (N=100, transplanted 12/2009-12/2011). Majority of patients except three in group 3 were diagnosed with CDI with a PCR based test. Results: All 3 groups were similar with respect to the baseline characteristics (Table 1). The median follow up for the 3 groups was 2 years. At a median follow up of 2 years the incidence of CDI in the three groups were 19%, 26%, 28% respectively, p=0.2 (table 2). The incidence of CDI prior to aGVHD was similar in three groups (18/100, 25/110 and 19/100 in groups 1, 2 and 3 respectively). The incidence of CDI after development of aGVHD was higher in group 3 (1/100, 4/110 and 9/100 p=0.06 in groups 1, 2 and 3 respectively). The incidence of Grade II-IV aGVHD was significantly higher in group 3 (63%) as compared to groups 1 and 2 (49 and 41%) p=0.006 (Table 2). Similarly the incidence of any grade GI GVHD was higher in group 3 (44% Vs 23% and 24%) p=0.0009. The median time to development of aGVHD was similar in all three groups (28 days in groups 1, 31 days in group 2 and 26 days in group 2). Multivariable analysis revealed that none of the factors examined (age, sex, diagnosis, intensity of conditioning, type of transplant, use of thymoglobulin, acute GVHD) was related to development of CDI. Development of GI GVHD tended to increase the risk of subsequent CDI (40% vs 27%, p=0.06). Development of CDI did not increase the risk of development of subsequent GI GVHD (30% vs. 26%). Use of thymoglobulin improved two year overall survival in patients undergoing unrelated transplant (p=0.006). Conclusion: Thymoglobulin use did not affect the overall incidence of CDI in recipients of Allo-SCT. There is a trend towards increased incidence of late onset CDI in patients undergoing unrelated Allo-SCT and not recieving thymoglobulin probably because of higher incidence of GVHD and steroid use. There was no difference in the incidence of CDI in related vs. unrelated transplant recipients. Use of thymoglobulin improved survival in recipients of unrelated Allo-SCT. Table 1. Baseline Characteristics: Related (N=100) unrelated with Thymo (N=110) Allo unrelated without Thymo (N=100) P-value Age Median 54 58 52 NS Gender F 42 47 51 NS M 58 63 49 Race Caucasian 83 99 91 NS Other 17 11 9 Conditioning regimen Myeloablative 76 59 63 NS RIC 24 51 37 Diagnosis Leukemia 47 61 56 NS Lymphoma 30 21 20 MDS 12 20 11 Other 11 8 13 Source of stem cells BM 9 6 10 NS PBSC 91 104 90 HLA match 10/10 94 71 71 NS* 9/10 2 26 21 8/10 13 8 Haploidentical 4 GVHD** Prophylaxis Tac/MMF 97 100 Tac/MMF/Thymo 101 Tac/Sirolimus/Thymo 9 *No difference in HLA match between the groups 2 and 3. **Tac (Tacrolimus); MMF (Mycophenolate Mofetil); THYMO (Thymoglobulin). Table 2. Results: Groups 1. Related 2. Unrelated with Thymo 3. unrelated without Thymo P value Incidence of aGVHD II-IV 48% 41% 63% p=0.006 Incidence of GI GVHD 23% 23.6% 44% p=0.0009 Use of systemic steroids 38% 32% 61% p=0.0001 Overall Incidence of CDI 19/100 (19%) 29/110 (26%) 28/100 (28%) p=0.20 Incidence of CDI prior to GVHD 18/100 (18%) 25/110 (22%) 19/100 (19%) NS Incidence of CDI after onset of GVHD 1/100 (1%) 4/110 (3.6)% 9/100 (9%) p=0.06 Median Overall survival at 2 year f/u 68% 52% 46% p=0.0057 Disclosures Deol: Bristol meyer squibb: Research Funding. Lum:Karyopharm Therapeutics Inc: Equity Ownership; Transtarget.Inc: Equity Ownership. Revankar:Actelion, Merck, Gilead, Astellas: Research Funding; Dara biosciences: Consultancy. Chandrasekar:Merck, Glaxo, Chimerix,: Research Funding.

Description: Central nervous system (CNS) infections caused by brown-black or dematiaceous fungi are distinctly rare and represent a small proportion of infections termed phaeohyphomycoses. However, these are becoming more commonly reported. Though many fungi have been implicated in disease, most cases are caused by only a few species, Cladophialophora bantiana being the most common. Most of the fungi described are molds, and often cause infection in immunocompetent individuals, in contrast to infection with other more common molds such as Aspergillus, which is usually seen in highly immunocompromised patients. Diagnosis is challenging, as there are no specific tests for this group of fungi. In addition, these infections are often refractory to standard drug therapies, requiring an aggressive combined surgical and medical approach to improve outcomes, yet mortality remains high. There are no standardized treatments due to a lack of randomized clinical trials, though guidelines have been published based on available data and expert opinion.