John Dotis

Scedosporium apiospermum infection after near-drowning.

Scedosporium apiospermum and its teleomorph (sexual form) Pseudallescheria boydii are ubiquitous saprophytic fungi, which under specific conditions, such as near‐drowning, may cause therapy‐refractory and life‐threatening infections. We reviewed 22 cases (eight children and 14 adults) of S. apiospermum infection after near‐drowning reported in the literature including an additional paediatric case from our institution. Scedosporiosis after near‐drowning was associated with high mortality (16/23, 70%) even in immunocompetent hosts. It affected mainly young (mean age 24 years) and immunocompetent (83% with no apparent immune defect) males (male to female ratio 2.5 : 1). Scedosporiosis after near‐drowning was a slow progressive disease (mean survival time 87 days) involving virtually all body organs. However, central nervous system (CNS) dissemination predominated (21/23, 91%) presenting mainly as multiple brain abscesses (15/23, 65%). All 23 patients showed preceding clinical and/or radiological evidence of lung disease indicating the mode of invasion. Diagnosis was delayed (median time to diagnosis 28 days) and was made by culture (16/23, 69.5%) or culture and tissue examination (7/23, 30.5%). The majority of the patients (20/23, 87%) received antifungal treatment and underwent neurosurgery. While the optimal treatment remains undefined, the most recent reports indicated voriconazole as a potentially effective option. Better knowledge of scedosporiosis after near‐drowning could lead to improved intervention and ultimately to more favourable outcome.

Differential Expression of Cytokines and Chemokines in Human Monocytes Induced by Lipid Formulations of Amphotericin B

ABSTRACT The immunomodulatory effects of liposomal amphotericin B (LAMB), amphotericin B lipid complex (ABLC), and amphotericin B colloidal dispersion (ABCD) on mRNA and protein profiles of five cytokines and chemokines expressed by human monocyte-enriched mononuclear leukocytes (MNCs) were comprehensively evaluated by semiquantitative reverse transcription-PCR and enzyme-linked immunosorbent assays; they were compared to those of deoxycholate amphotericin B (DAMB). mRNAs of interleukin-1β (IL-1β), IL-1 receptor antagonist (IL-1ra), tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 1β (MIP-1β) were assessed after treatment of MNCs with each drug for 0.5, 2, 6, and 22 h. The cytokine protein profiles were obtained after incubation of MNCs with the drugs for 2 h (TNF-α) or 6 h (all the others). In the mRNA studies, DAMB resulted in an early increase of inflammatory cytokines or chemokines IL-1β, TNF-α, MCP-1, and MIP-1β (2 to 6 h) and in a late increase of anti-inflammatory IL-1ra (22 h). ABCD showed a general similar trend of inflammatory gene up-regulation. LAMB and ABLC decreased or did not affect IL-1β and TNF-α, whereas ABLC additionally decreased MIP-1β. In protein measurement studies, DAMB and ABCD up-regulated production of IL-1β (P < 0.05), decreased the IL-1ra/IL-1β ratio, and up-regulated the production of MCP-1 and MIP-1β. In comparison, LAMB and ABLC down-regulated or did not affect the production of these cytokines/chemokines compared to untreated MNCs; furthermore, ABLC tended to increase the IL-1ra/IL-1β ratio. These studies demonstrate that amphotericin B formulations differentially affect gene expression and release of an array of proinflammatory and anti-inflammatory cytokines that potentially may explain the differences in infusion-related reactions and dose-dependent nephrotoxicity as well as modulation of the host immune response to invasive fungal infections.

Femoral Osteomyelitis Due to Aspergillus nidulans in a Patient with Chronic Granulomatous Disease

Abstract.13 cases of osteomyelitis caused by Aspergillus nidulans have been previously reported in patients with chronic granulomatous disease (CGD). All of them have been associated with simultaneous pulmonary infection and have had an extremely poor outcome. We report an unusual case of femoral osteomyelitis due to A. nidulans in a 16-year-old male with CGD, without pulmonary involvement. Treatment with liposomal amphotericin B and granulocyte colonystimulating factor as well as extensive surgical debridement followed by prolonged treatment with itraconazole resulted in an excellent clinical response.

Epidemiology, Risk Factors and Outcome of Candida parapsilosis Bloodstream Infection in Children

Background: Candida parapsilosis constitutes a common Candida spp. isolated in children with candidemia. Few data exist on risk factors and outcome of candidemia caused by C. parapsilosis in pediatric patients. Methods: We conducted a retrospective analysis of demographic data, clinical features, therapeutic procedures and outcomes associated with Candida bloodstream infections (BSIs) that occurred at the Children’s Hospital of Philadelphia between 1997 and 2009. Results: Among 406 Candida BSIs, Candida albicans accounted for 198 (49%), C. parapsilosis for 99 (24%) and all other species for 109 (27%) episodes. There was no consistent change in the proportion of C. parapsilosis BSIs during the study. C. parapsilosis BSI was more frequent than non-parapsilosis Candida spp. at age ⩽2 years as compared with older patients (62% versus 50%, odds ratio = 1.24, 95% confidence interval: 1.03–1.51, P = 0.038). Patients with C. parapsilosis were more likely to be mechanically ventilated within 48 hours of BSI (odds ratio = 1.38, 95% confidence interval: 1.01–1.85, P = 0.047). Presence of a urinary catheter a week before infection was a protective factor for developing candidemia due to C. parapsilosis spp. (P = 0.003). No significant differences were found between the 2 groups in the presence of central intravascular catheters, comorbidities and clinical or surgical procedures, previous administration of immunosuppressive or antifungal agents and mortality. Conclusions: C. parapsilosis is the second most frequent cause of candidemia after C. albicans. Although it is more frequent at the age of ⩽2 years and is more likely associated with mechanical ventilation than other Candida spp., mortality does not significantly differ between those with and without C. parapsilosis candidemia.

Use of linezolid in pediatrics: a critical review.

BACKGROUND Linezolid, an oxazolidinone antibacterial agent, is available for intravenous/oral administration, with activity against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and penicillin-resistant Streptococcus pneumoniae (PRSP). These pathogens are important causes of hospital- and community-associated infections in children. METHODS PubMed was searched for all English language articles on patients younger than 18 years of age treated with linezolid, and an analysis of these articles was performed. RESULTS From the 133 articles retrieved, a total of 30 were studied (18 case reports, nine case series, and three clinical trials) based on the inclusion criteria preset for this review. In these articles, a total of 597 children received linezolid. MRSA was the most common pathogen, followed by VRE, PRSP, other bacteria and less common mycobacterial species. Linezolid was reported to be safe and effective for the treatment of pneumonia and endocarditis, as well as skin and soft tissue, central nervous system and osteoarticular infections. CONCLUSIONS Linezolid is promising as a safe and efficacious agent for the treatment of infections due to mainly resistant Gram-positive organisms in children who are unable to tolerate conventional agents or after treatment failure.

Effects of Lipid Formulations of Amphotericin B on Activity of Human Monocytes against Aspergillus fumigatus

ABSTRACT The immunomodulatory effects of liposomal amphotericin B (LAMB), amphotericin B lipid complex, and amphotericin B colloidal dispersion (ABCD) on antifungal activity of human monocytes (MNCs), an important component of antifungal host defense, against Aspergillus fumigatus were compared to those of deoxycholate amphotericin B (DAMB). MNCs from healthy volunteers were incubated with 1 or 5 μg/ml DAMB and 5 or 25 μg/ml lipid formulations for 22 h. Drug-pretreated or untreated MNCs were then washed and assayed for the following: (i) activity against A. fumigatus hyphae by XTT assay at MNC:hypha ratios of 10:1 and 20:1; (ii) production of superoxide anion (O2−) from MNCs in response to hyphae by cytochrome c reduction; (iii) production of hydrogen peroxide (H2O2) and H2O2-dependent intracellular intermediates (DIIs), such as OH− and HOCl, from MNCs in response to A. fumigatus culture supernatant by flow cytometric measurement of dihydrorhodamine-1,2,3 oxidation. With the exception of 1 μg/ml DAMB and 5 μg/ml LAMB or ABCD at 10:1, all amphotericin B formulations at both concentrations and MNC:hypha ratios enhanced MNC-induced damage of A. fumigatus hyphae compared to results with untreated cells (P < 0.01). While MNC O2− production upon hyphal challenge, an early event in oxidative burst, was not affected by the drugs, production of H2O2 and DIIs, late events, were significantly increased by all four drugs (P < 0.01). At clinically relevant concentrations, both conventional amphotericin B and its lipid formulations enhance antihyphal activity of MNCs against A. fumigatus in association with significant augmentation of H2O2 and DIIs but not O2−, further demonstrating the immunomodulatory antifungal activities of these agents.

Osteomyelitis due to Aspergillus species in chronic granulomatous disease: an update of the literature

Chronic granulomatous disease (CGD) is a rare inherited disorder characterised by inability of phagocytes to kill catalase‐positive organisms including certain fungi. Aspergillus species are the most frequent fungal pathogens. This study is a systematic review of the reported cases of osteomyelitis due to Aspergillus species in CGD patients. Retrospective analysis of 46 osteomyelitis cases caused by Aspergillus species in 43 CGD patients (three females) published in the English literature (PubMed) was performed. Twenty‐three cases were due to Aspergillus fumigatus (50%), 20 to Aspergillus nidulans (43.5%), one to Aspergillus flavus and two to unspecified Aspergillus species. The median age was 8 years (range 1.5–21). Osteomyelitis due to A. nidulans was associated with pulmonary infection and involved ‘small bones’ more frequently than A. fumigatus osteomyelitis (P = 0.001). Amphotericin B was used in 91.3% and surgical debridement in 67.4% of all cases. The overall mortality of osteomyelitis due to Aspergillus species in CGD patients was 37%; 55% for A. nidulans compared to 13% for A. fumigatus (P = 0.008). Aspergillus fumigatus causes osteomyelitis in CGD patients almost as frequently as A. nidulans and much more frequently than A. flavus. Osteomyelitis due to A. nidulans is associated with higher mortality than A. fumigatus.

Amphotericin B formulations variably enhance antifungal activity of human neutrophils and monocytes against Fusarium solani : comparison with Aspergillus fumigatus

OBJECTIVES Lipid formulations of amphotericin B (AMBF) are widely used in the treatment of life-threatening infections caused by Aspergillus fumigatus and Fusarium solani. We aimed to compare the immunomodulatory effects of four AMBF, deoxycholate (DAMB), liposomal (LAMB), lipid complex (ABLC) and colloidal dispersion (ABCD), on the oxidative antifungal activities of human neutrophils (PMNs) and monocytes (MNCs) against hyphae of A. fumigatus and F. solani. METHODS Human PMNs and MNCs were pre-incubated with 1 or 5 mg/L DAMB and 5 or 25 mg/L for each of LAMB, ABLC and ABCD. Hyphal damage was then assessed by XTT assay, and O2- production was assessed by cytochrome c assay. RESULTS All agents resulted in increased hyphal damage induced by phagocytes against both A. fumigatus and F. solani (P < 0.05). The high concentrations of AMBF elicited higher phagocyte-induced hyphal damage of both fungi than the low concentrations. There was, however, no consistent superiority of any of the AMBF or substantial effector cell:target ratio-dependent differences in the degree of hyphal damage enhancement. By comparison, O2- produced by PMNs or MNCs upon hyphal challenge was not generally affected by any of the AMBF. F. solani hyphae were significantly more resistant to H2O2 than A. fumigatus. CONCLUSIONS These findings suggest that AMBF have enhancing effects of variable degree on phagocyte-induced hyphal damage of A. fumigatus and F. solani. Other fungicidal mechanisms, perhaps non-oxidative, are more likely to mediate these immunomodulatory effects of AMBF on host defence against the two medically important filamentous fungi.

Non-Aspergillus fungal infections in chronic granulomatous disease

Chronic granulomatous disease (CGD) is a congenital immunodeficiency, characterised by significant infections due to an inability of phagocyte to kill catalase‐positive organisms including certain fungi such as Aspergillus spp. Nevertheless, other more rare fungi can cause significant diseases. This report is a systematic review of all published cases of non‐Aspergillus fungal infections in CGD patients. Analysis of 68 cases of non‐Aspergillus fungal infections in 65 CGD patients (10 females) published in the English literature. The median age of CGD patients was 15.2 years (range 0.1–69), 60% of whom had the X‐linked recessive defect. The most prevalent non‐Aspergillus fungal infections were associated with Rhizopus spp. and Trichosporon spp. found in nine cases each (13.2%). The most commonly affected organs were the lungs in 69.9%. In 63.2% of cases first line antifungal treatment was monotherapy, with amphotericin B formulations being the most frequently used antifungal agents in 45.6% of cases. The overall mortality rate was 26.2%. Clinicians should take into account the occurrence of non‐Aspergillus infections in this patient group, as well as the possibility of a changing epidemiology in fungal pathogens. Better awareness and knowledge of these pathogens can optimise antifungal treatment and improve outcome in CGD patients.

Immunopathogenesis of central nervous system fungal infections.

Fungal infections of the central nervous system (CNS) evoke humoral and cellular immune responses with the scope to enable the host to eliminate the pathogen. Immunopathogenesis of CNS fungal infections remains incompletely understood, with most of our understanding coming from studies on experimentally infected animals. However, activation of brain resident cells combined with relative expression of immunoenhancing and immunosuppressing cytokines and chemokines may play a determinant role and partially explain immunopathogenesis of CNS fungal infections.