Invasive Pilzinfektionen bei Patienten nach Lebertransplantation. Invasive fungal infections in patients after liver transplantation

Invasive fungal infection in liver transplant recipients in a prophylactic era: A multicenter retrospective cohort study in Korea

The epidemiology of invasive fungal infections (IFIs) after liver transplantation (LT) is continuing to evolve in the current era of antifungal prophylactic therapy. This multicenter retrospective cohort study aimed to evaluate the epidemiology, risk factors, and outcomes of IFIs among LT recipients in the current era.We analyzed a total of 482 LT recipients aged 18 years and older who were admitted to 3 tertiary hospitals in Korea between January 2009 and February 2012.Twenty-four episodes of IFIs occurred in 23 patients (4.77%; 23/482). Of these episodes, 20 were proven cases and 4 were probable cases according to EORTC/MSG criteria. Among these cases, IFI developed within 30 days of transplantation in 47.8% of recipients, from 31 to 180 days in 34.8% of recipients, and from 181 to 365 days in 17.4% of recipients. The most common isolates were Candida species (n = 12, 52.2%; Candida albicans, 6 cases; Candida tropicalis, 1 case; Candida glabrata, 1 case; Candida parapsilosis, 1 case; and unspecified Candida species, 1 case) and Aspergillus species (n = 7, 30.4%). The mortality in patients with IFIs was significantly higher than that in patients without IFIs (47.83% [11/23] vs 7.18% [33/459], P < .001). The incidence of late-onset IFIs is increasing in the antifungal prophylactic era, and fluconazole-resistant non-albicans Candida species have not yet emerged in Korea.

Mycobacterium tuberculosis in a red-crowned parakeet (Cyanoramphus novaezelandiae)

An adult female red-crowned parakeet (Cyanoramphus novaezelandieae) was presented for necropsy and histopathologic evaluation. The bird had died after exhibiting lameness, weight loss, respiratory signs, and hemoptysis. Postmortem radiographs revealed lesions in the diaphysis of the left femur and soft-tissue opacities in the lungs. At necropsy, the muscles of the left femur were pale and swollen, white-yellow small nodules were visible in lungs and air sacs, and the liver and other coelomic organs appeared pale. On histologic examination, areas of necrosis in the lungs were extensively infiltrated with acid-fast positive bacilli surrounded by macrophages, epithelioid cells, and giant cells. Acid-fast bacilli were also present in the left leg muscle and in granulomas in the liver, kidneys, and intestine. Fungal hyphae associated with a Splendore-Hoeppli phenomenon were visible in the left leg muscle. Mycobacterium tuberculosis was confirmed by polymerase chain reaction testing performed on muscle samples. Results were indicative of infection with M tuberculosis complicated by mycotic myositis. The disease in avian species is of zoonotic importance, and infected birds may be a useful sentinel for human infection.

Candida and invasive candidiasis: back to basics

The ubiquitous Candida spp. is an opportunistic fungal pathogen which, despite treatment with antifungal drugs, can cause fatal bloodstream infections (BSIs) in immunocompromised and immunodeficient persons. Thus far, several major C. albicans virulence factors have been relatively well studied, including morphology switching and secreted degradative enzymes. However, the exact mechanism of Candida pathogenesis and the host response to invasion are still not well elucidated. The relatively recent discovery of the quorum-sensing molecule farnesol and the existence of quorum sensing as a basic regulatory phenomenon of the C. albicans population behavior has revolutionized Candida research. Through population density regulation, the quorum-sensing mechanism also controls the cellular morphology of a C. albicans population in response to environmental factors, thereby, effectively placing morphology switching downstream of quorum sensing. Thus, the quorum-sensing phenomenon has been hailed as the 'missing piece' of the pathogenicity puzzle. Here, we review what is known about Candida spp. as the etiological agents of invasive candidiasis and address our current understanding of the quorum-sensing phenomenon in relation to virulence in the host.

Invasive fungal infections in patients with systemic lupus erythematosus: experience from affiliated hospitals of Catholic University of Korea

The purpose of study was to determine the nature, outcomes and associated risk factors of invasive fungal infection (IFI) in patients with systemic lupus erythematosus (SLE), and compare the incidence of IFI in patients with rheumatoid arthritis (RA). A total of 1155 patients with SLE and 2004 patients with RA were retrospectively reviewed between 1992 and 2007. Twelve cases of IFI patients were identified in SLE patients (6 Aspergillus spp.; 5 Cryptococcus spp.; 1 Candida spp.). The incidence of IFI was significantly higher in patients with SLE than RA (1.04 vs. 0.15%). Among 12 patients with SLE, 10 had high Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores (≥8). The most commonly involved organ was the lung (n = 6), followed by the meninges (n = 4). Most of SLE patients with IFI (91.7%) had taken steroids prior to IFI. Three SLE patients resulted in death. Notably, these patients were all infected with Aspergillus spp. The mortality was associated with the presence of leukopenia, high anti-DNA antibodies and high SLEDAI. Collectively, IFI is more common in patients with SLE than in patients with RA. High disease activity in patients with SLE might contribute to increased risk of IFI. In addition, mortality was associated with aspergillus infection, leukopenia and high anti-DNA antibodies.

In vivo and ex vivo comparative transcriptional profiling of invasive and non-invasive Candida albicans isolates identifies genes associated with tissue invasion

The human pathogenic fungus Candida albicans can cause a wide range of infections and invade multiple organs. To identify C. albicans genes that are expressed during invasion of the liver, we used genome-wide transcriptional profiling in vivo and ex vivo. By analysing the different phases of intraperitoneal infection from attachment to tissue penetration in a time-course experiment and by comparing the profiles of an invasive with those of a non-invasive strain, we identified genes and transcriptional pattern which are associated with the invasion process. This includes genes involved in metabolism, stress, and nutrient uptake, as well as transcriptional programmes regulating morphology and environmental sensing. One of the genes identified as associated with liver invasion was DFG16, a gene crucial for pH-dependent hyphal formation, correct pH sensing, invasion at physiological pH and systemic infection.

Haemoperfused liver as an ex vivo model for organ invasion of Candida albicans

To study invasion of the human fungal pathogen Candida albicans, several infection models have been established. This study describes the successful establishment of an ex vivo haemoperfused liver as a model to study invasion of C. albicans. Perfused organs from pigs could be kept functional for up to 12 h. By comparing a non-invasive and invasive strain of C. albicans and by following a time course of invasion, it was shown that the invasion process in the perfused liver infection model is very similar to the in vivo situation after intraperitoneal infection of mice. The advantage of this set-up compared with other models of invasion is discussed.