Disseminated Trichosporon infection, an uncommon but emerging opportunistic mycosis due to Trichosporon beigelii, is frequently difficult to diagnose, refractory to treatment, and associated with a high attributable mortality. Models of disseminated and gastrointestinal Trichosporon infection were developed in persistently granulocytopenic rabbits. The patterns of infection resembled those of clinical disease, including cutaneous lesions, chorioretinitis, renal infection, pulmonary infection, and antigenemia cross-reactive with cryptococcal capsular polysaccharide. Antigenemia, an early manifestation of disseminated Trichosporon infection, originated in vivo from a fibrillar extracellular matrix. Trichosporon organisms disseminated from the gastrointestinal tract to visceral tissue in colonized immunosuppressed rabbits, whereas there was no dissemination from the gastrointestinal tract of otherwise normal rabbits. The antifungal triazoles, fluconazole and SCH 39304, were most active; maximum tolerated doses of amphotericin B and liposomal amphotericin B were ineffective. Trichosporon antigenemia declined in response to antifungal therapy. These findings contribute to improved understanding of the pathogenesis, diagnosis, and treatment of disseminated Trichosporon infection.
Trichosporon beigelii caused fatal disseminated infections that were resistant to amphotericin B in two granulocytopenic patients. In vitro susceptibility studies demonstrated that both index strains of T. beigelii were inhibited but not killed by amphotericin B at achievable concentrations in serum. The minimum lethal concentration for both isolates was. 18 ,gg/m1. Five of seven other isolates were found to have a similar pattern of amphotericin B resistance. The fact that the minimum lethal concentration of T. beigelii was many times greater than its MIC was consistent with a resistance pattern of tolerance. We concluded that T. beigelii may be resistant in vitro to amphotericin B and that this in vitro resistance was correlated with refractory, disseminated trichosporonosis in granulocytopenic patients. T. beigelii should be included in the expanding list of amphotericin B-resistant fungi.
During a 15-month period, 92 patients undergoing 129 treatment episodes of immunotherapy with interleukin-2 (IL-2) alone or with immune cells underwent insertion of central venous catheters (CVCs) in the Surgery Branch, National Cancer Institute. Before each catheter insertion patients were prospectively randomized into one of three treatment groups; therapy with intravenous (IV) placebo using D5W, IV oxacillin, or change of the catheter to a new site every 72 hours. The mean duration of catheterization was 3.8 +/- 1.1 days. No patient in the oxacillin arm developed catheter-related sepsis, while eight patients in the control arms (five, line change, three, placebo) developed catheter-related sepsis (P2 = .050). Seven episodes of catheter-related sepsis were due to Staphylococcus aureus and one was due to Staphylococcus epidermidis. Catheter colonization was reduced significantly in the oxacillin arm versus control arms (P = .0001). Staphylococcus aureus, Staphylococcus epidermidis, and other coagulase-negative Staphylococci were sensitive to oxacillin in 89%, 60%, and 50% of cultures, respectively. No evidence of bacterial overgrowth, candida colonization, or candidemia was observed in these patients. Thus this trial demonstrates that treatment with prophylactic oxacillin can decrease the incidence of catheter-related sepsis in patients undergoing immunotherapy with interleukin-2 (IL-2). To our knowledge this is the first prospective randomized trial to evaluate the prophylactic use of systemic antibiotics in the prophylaxis of CVC sepsis.
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