Association of reduced total iron binding capacity and fungal infections in leukemic granulocytopenic patients.

Serum total iron-binding capacity (TIBC) was measured serially on 70 patients with acute leukemia throughout the period of chemotherapy-induced granulocytopenia. Fungal infections were documented in 13 of these patients (18.6%), while 41 patients (58.6%) had clinically suspected fungal infections and 16 (22.9%) had no evidence of fungal infections during the granulocytopenia. Documented fungal infection occurred in patients with the greatest reduction in TIBC (P less than .015). Early reduction in TIBC also correlated with a greater risk for occurrence of fungal infection, and the earliest institution of amphotericin B (Amp-B) (P less than .004). Effective antifungal therapy was further associated with a return of TIBC levels toward normal. These data demonstrate that altered iron metabolism during granulocytopenia is associated with the development of fungal infections in compromised patients. Serial monitoring of TIBC, along with other clinical and mycologic findings, may prove useful in developing strategies for predicting patients at risk for developing a fungal infection and directing the appropriate use of empiric therapy with Amp-B.

Favorable outcome of invasive aspergillosis in patients with acute leukemia.

During a 2-year period, 15 of 110 patients (14%) admitted for intensive therapy of acute leukemia associated with prolonged deep granulocytopenia developed documented invasive aspergillosis (IA). Antemortem diagnosis was accomplished in 14, and 13 of 15 (87%) survived the infection. Because of the high success rate, we reviewed the courses of the 15 patients to assess factors associated with this favorable outcome. Eleven presented with pulmonary IA; early symptoms occurred at a mean 21.6 days of granulocytopenia (less than 100/muL) and included refractory fever in 14 and pulmonary signs or symptoms in 11. Primary necrotic chest wall lesions associated with Hickman catheters developed in four at a mean 11 days of granulocytopenia, followed by pulmonary involvement. All 15 patients had chest radiographs during granulocytopenia, with 14 (93%) demonstrating pulmonary infiltrates and/or nodules at a mean 20.6 days of aplasia. Nine patients had lung computerized tomography (CT) scans, revealing nodular infiltrates in one patient and a characteristic zone of low attenuation surrounding a mass-like infiltrate in seven other patients, which was found to be diagnostic of IA. Subsequent CT scans performed during and following bone marrow recovery showed progression to cavitation followed by either complete resolution or minimal pulmonary scarring. Eleven patients developed IA during empiric amphotericin B (Amp-B) therapy (0.5 mg/kg/d) for fever refractory to antibacterial antibiotics. Fourteen patients received high-dose Amp-B (1.0 to 1.5 mg/kg/d), which was started within a mean of 2.2 days of first clinical findings; 13 survived. Ten patients received 5-fluorocytosine in addition to high dose amp-B. Survival was similar regardless of presentation, as 91% with primary pulmonary IA and 75% presenting with chest wall lesions survived. All 13 surviving patients had complete granulocyte recovery at a mean 33.8 days. Nephrotoxicity (creatinine greater than 2.0 mg/dL) was observed in seven patients during therapy for IA, but was transient in all seven. We conclude IA can be successfully treated in the deeply granulocytopenic patient provided that it is recognized and treated early, and provided that antifungal therapy is aggressive and is continued until granulocyte recovery occurs.

An approach to intensive antileukemia therapy in patients with previous invasive aspergillosis.

PURPOSE: In an attempt to decrease the risk for reactivation of life-threatening invasive aspergillosis (IA) during subsequent myelosuppression in patients with previously diagnosed IA who were receiving antileukemic treatment, we evaluated the role of intensive antifungal therapy with amphotericin B and 5-fluorocytosine administered prophylactically throughout the antileukemic regimen and induced granulocytopenia to prevent IA reactivation without compromising the intensive chemotherapy. PATIENTS AND METHODS: During a 30-month period, 10 patients with acute myelogenous leukemia and primary IA developing during initial antileukemia induction therapy and severe granulocytopenia (less than 100/mm3) underwent 14 subsequent courses of intensive marrow aplasia-producing chemotherapy during early complete remission or at leukemia relapse. All patients had evidence of ongoing IA healing by lung computerized tomography (CT) prior to reinstitution of intensive chemotherapy. Nine patients receiving 13 chemotherapy courses also received aggressive prophylactic anti-IA therapy with amphotericin B (1.0 mg/kg/day) and 5-fluorocytosine beginning at least 48 hours prior to antileukemia therapy institution and continued until the time of granulocyte recovery. RESULTS: All nine patients receiving aggressive antifungal therapy survived without clinical evidence of IA reactivation. Transient radiographic evidence of IA reactivation during granulocytopenia was detected by lung CT during two of the 13 chemotherapy courses. In contrast, the patient who did not receive anti-IA prophylaxis had both clinical and radiographic evidence of IA reactivation during severe granulocytopenia and died. Anti-IA prophylaxis was achieved without irreversible nephrotoxicity, prolonged marrow suppression, alteration of antileukemia treatment, or negative impact on clinical outcome relative to acute leukemia. CONCLUSION: This approach of antifungal prophylaxis in adults with acute leukemia and documented primary IA occurring during initial induction chemotherapy has been successful in preventing clinically significant IA reactivation during subsequent granulocytopenic courses, and allows for administration of additional intensive antileukemia therapy.

Prevention of fungal sepsis in patients with prolonged neutropenia: a randomized, double-blind, placebo-controlled trial of intravenous miconazole.

Patients treated with cytotoxic therapy expected to produce neutropenia lasting two or more weeks were randomly assigned in a double-blind study to receive intravenous miconazole or placebo concomitant with empiric antibiotics to test whether miconazole can prevent fungal sepsis. The study drug was initiated at the time of first fever along with antibiotics and was continued until neutropenia resolved, fungal sepsis occurred, or persistent or recurrent unexplained fever after six or more days prompted substitution of the study drug by amphotericin B. Two hundred eight treatment courses in 180 patients were evaluated. Fungal sepsis occurred in only one patient receiving miconazole compared with eight patients receiving placebo (p = 0.03). Fatal fungal sepsis occurred in four patients receiving placebo and in none of the patients receiving miconazole (p = 0.08). There was no evidence for the development of resistance to polyenes or imidazoles in fungal isolates recovered from patients in this randomized trial or an increase in Aspergillus infections in patients who received miconazole in this randomized trial or in 121 subsequently treated patients who received unblinded use of miconazole. Thus, intravenous miconazole was more effective than placebo in preventing fungal sepsis in patients with chemotherapy-induced prolonged neutropenia.

Diagnosis and therapeutic monitoring of invasive candidiasis by rapid enzymatic detection of serum D-arabinitol.

BACKGROUND: Using a rapid automated enzymatic assay, we prospectively investigated serum D-arabinitol (DA), a biochemical marker of invasive candidiasis, in a large population of high-risk patients to determine its potential diagnostic, therapeutic, and prognostic significance in invasive candidiasis. PATIENTS AND METHODS: A total of 3,223 serum samples were collected from 274 patients with cancer. Serum DA concentrations were determined in coded serum samples analyzed by rapid enzymatic assay. Creatinine also was analyzed in the same system to determine a serum DA and creatinine ratio (DA/Cr). The sensitivity, specificity, correlation with therapeutic response, and prognostic significance were analyzed for all patient study groups. RESULTS: A DA/Cr of > or = 4.0 mumol/L per mg/dL was detected in 31 (74%) of all 42 cases of fungemia and 25 (83%) of the 30 cases of the subset of persistent fungemia. Elevated DA/Cr was detected in 4 (40%) of 10 patients with tissue-proven, deeply invasive candidiasis and negative blood cultures (eg, hepatosplenic candidiasis or localized abscess) and 7 (44%) of 16 cases of deep mucosal candidiasis (eg, esophageal candidiasis). Elevated serial DA/Cr levels also were detected in persistently febrile and granulocytopenic patients requiring empirical amphotericin B. Among 26 assessable cases of fungemia, abnormally elevated DA/Cr values were detected in 14 (54%) before, 10 (38%) after, and 2 (8%) simultaneously with the first microbiologic report of fungemia. The trends of serial DA/Cr values correlated with therapeutic response in 29 (85%) of 34 patients with assessable cases of fungemia, decreasing in 8 (89%) of 9 patients with clearance of fungemia and increasing in 21 (84%) of 25 patients with persistence of fungemia. Among the 34 assessable patients with fungemia, mortality was directly related to the trend of serial DA/Cr determinations over time: 71% among fungemic patients who had persistently elevated or increasing DA/Cr, and 18% among the fungemic patients who had resolving DA/Cr or never had elevated DA/Cr (P < 0.01). CONCLUSIONS: Rapid enzymatic detection of DA in serially collected serum samples from high-risk cancer patients permitted detection of invasive candidiasis, early recognition of fungemia, and therapeutic monitoring in DA-positive cases. Serially collected serum DA determinations complement blood cultures for improving detection and monitoring therapeutic response in patients at risk for invasive candidiasis.

Aspergillus osteomyelitis in an immunocompetent adolescent: a case report and review of the literature.

A black male adolescent with intact cellular and humoral immunity developed Aspergillus flavus-caused osteomyelitis involving the right tibial epiphysis following penetrating injury to that area. There was an apparent cure following amphotericin B therapy for six weeks. The clinical, pathologic, and therapeutic features of this case are described and compared with those in previously published cases. This case report represents the first well documented case of Aspergillus osteomyelitis in an immunocompetent host. The increasing incidence of invasive disease due to Aspergillus species and the increased awareness of the incidence of mycotic bone infections, particularly in pediatric patients, may allow further definition of pathogenesis and appropriate therapy.

Strategies to prevent or control infections after bone marrow transplants.

Patients receiving bone marrow transplants are at risk of life-threatening infections early post-transplant. This predisposition results from extensive mucosal damage and severe granulocytopenia. Common causes of infection include bacteria and fungi. Infections with opportunistic pathogens occur later and are associated with defects in cellular and/or humoral immunity. The most common sites of infections are the gastrointestinal tract, oropharynx, lung, skin and indwelling vascular catheters. Empiric approaches designed to treat common bacterial and fungal pathogens are generally effective as are measures designed to prevent dissemination of infections. These approaches are also used to prevent fungal infections.

Aspergillus infections in bone marrow transplant recipients.

Aspergillus infection was studied in patients admitted to the Bone Marrow Transplant (BMT) Service at the Johns Hopkins Oncology Center during a 9-year period. The overall incidence was 4% in 549 patients reviewed. The incidence at autopsy was 12% (21 of 174 patients autopsied). There was no difference in frequency of occurrence in allogeneic compared to autologous BMT recipients. However, all infections in autologous BMT patients (5 of 5) occurred during neutropenia before engraftment. In contrast, 16 of 17 infections in allogeneic BMT patients occurred after engraftment (p = 0.0002). This difference presumably related to differences in duration of neutropenia and immunodeficiency. Age, underlying disease, date of BMT, preparative regimen, remission status, prior treatment, interstitial pneumonitis and concomitant cytomegalovirus infection did not predispose patients to aspergillus infection. Different post-BMT immunosuppressive regimens did not affect the risk for aspergillus infection except that patients who were given cyclophosphamide plus methylprednisolone had a higher incidence of aspergillus infection than those given methotrexate (12% versus 1%, p = 0.03). Acute graft-versus-host disease imposed a slight risk for infection (p = 0.06).

Refinements of environmental assessment during an outbreak investigation of invasive aspergillosis in a leukemia and bone marrow transplant unit.

OBJECTIVES: To investigate an outbreak of aspergillosis in a leukemia and bone marrow transplant (BMT) unit and to improve environmental assessment strategies to detect Aspergillus. DESIGN: Epidemiological investigation and detailed environmental assessment. SETTING: A tertiary-care university hospital with a 37-bed leukemia and BMT unit PARTICIPANTS: Leukemic or BMT patients with invasive aspergillosis identified through prospective surveillance and confirmed by chart review. INTERVENTIONS: We verified the diagnosis of invasive fungal infection by reviewing medical charts of at-risk patients, performing a case-control study to determine risk factors for infection, instituting wet mopping to clean all floors, providing N95 masks to protect patients outside high-efficiency particulate air (HEPA)-filtered areas, altering traffic patterns into the unit, and performing molecular typing of selected Aspergillus flavus isolates. To assess the environment, we verified pressure relationships between the rooms and hallway and between buildings, and we compared the ability of large-volume (1,200 L) and small-volume (160 L) air samplers to detect Aspergillus spores. RESULTS: Of 29 potential invasive aspergillosis cases, 21 were confirmed by medical chart review. Risk factors for developing invasive aspergillosis included the length of time since malignancy was diagnosed (odds ratio [OR], 1.0; P=.05) and hospitalization in a patient room located near a stairwell door (OR, 3.7; P=.05). Two of five A. flavus patient isolates were identical to one of the environmental isolates. The pressure in most of the rooms was higher than in the corridors, but the pressure in the oncology unit was negative with respect to the physically adjacent hospital; consequently, the unit acted essentially as a vacuum that siphoned non-HEPA-filtered air from the main hospital. Of the 78 samples obtained with a small-volume air sampler, none grew an Aspergillus species, whereas 10 of 40 cultures obtained with a large-volume air sampler did. CONCLUSIONS: During active construction, Aspergillus spores may have entered the oncology unit from the physically adjacent hospital because the air pressure differed. Guidelines that establish the minimum acceptable pressures and specify which pressure relationships to test in healthcare settings are needed. Our data show that large-volume air samples are superior to small-volume samples to assess for Aspergillus in the healthcare environment.

Pathologic features in the human alimentary tract associated with invasiveness of Candida tropicalis.

The pathologic features of Candida albicans and Candida tropicalis in 23 consecutive autopsied patients with culture-proven disseminated candidiasis were studied in order to determine the pathologic basis for the greater virulence of C. tropicalis. Disseminated C. tropicalis infection with gastrointestinal invasion occurred only in eight neutropenic patients; whereas, C. albicans infection occurred in nine neutropenic and six nonneutropenic patients. C. tropicalis involved the entire alimentary tract in four of eight patients versus one of fifteen patients with C. albicans. C. tropicalis penetrated to the deep submucosa in six of eight patients with C. tropicalis and four of fifteen patients with C. albicans. Nine of ten patients with submucosal invasion were neutropenic. Invasion of submucosal blood vessels occurred in six of eight patients with C. tropicalis and only two of fifteen patients with C. albicans. All patients with submucosal blood-vessel invasion were neutropenic. A band of tissue necrosis at the advancing mycelial margin was present with C. tropicalis but not with C. albicans. These autopsy findings indicate that the greater virulence of C. tropicalis is related to increased invasiveness in the gastrointestinal tract in susceptible hosts.

Three serologic tests for candidiasis. Diagnostic value in distinguishing deep or disseminated infection from superficial infection or colonization.

One hundred fifty-one sera from 100 hospitalized patients with positive cultures for yeasts were assayed using whole-cell agglutination (Aggl.), agar gel diffusion (AGD), and counterimmunoelectrophoresis (CEP) to determine the relative diagnostic values of three serologic tests for anti-Candida antibodies. Serial samples were obtained from 29 patients. Tests were read blindly; correlations of the three test results with culture results and clinical findings were determined only after all data had been accumulated. Thirty-five of 100 patients had Aggl. titers of 1:160 or greater, although 13/35 had no evidence of deep or disseminated disease. Twenty-four of 100 patients had clinical or autopsy evidence of deep or disseminated candidiasis; 22/24 had Aggl. titers of 1:160 or greater. Twenty of the 24 patients were CEP-positive, whereas 18/24 were AGD-positive. In five patients CEP became positive earlier (10--21 days) than AGD. Three patients had false-positive precipitin tests, two by both CEP and AGD and the third by CEP only. In this population, a positive CEP and a positive AGD test showed good correlation with deep or disseminated candidiasis, whereas a negatvie Aggl. test showed the best correlation for excluding deep or systemic candidiasis.

Detection of surgical pathogens by in vitro DNA amplification. Part I. Rapid identification of Candida albicans by in vitro amplification of a fungus-specific gene.

The management of candidemia and disseminated candidiasis depends on rapid, unambiguous identification of Candida. Such identification is retarded by the slow growth of Candida from clinical specimens. Administration of effective but potentially toxic antifungal therapy is often withheld pending identification. To circumvent this slow growth and thus to expedite diagnosis and therapy, the polymerase chain reaction (PCR) was used to amplify a segment of fungal DNA coding for the cytochrome P450L1A1 (lanosterol-14 alpha-demethylase) in vitro. The technique provides unambiguous evidence of C. albicans in as few as 6 hours with a detection threshold of 10 organisms in a 100 mu specimen. Clinical specimens of urine (n = 4), sputum (n = 6), wound fluid (n = 1, and blood (n = 2) were collected from patients, and C. albicans was conventionally documented at these sites; in each case, PCR was confirmed. Of 17 additional specimens that were culture negative, PCR suggested the presence of yeast in two of the specimens. PCR-based detection of surgical pathogens may have broad application in rapid screening for the presence of organisms either indigenous to a particular surgical intensive care unit or peculiar to selected patient populations.

Primary cutaneous phaeohyphomycosis caused by Drechslera spicifera.

A primary cutaneous lesion in a 5-year-old boy who had recently received chemotherapy for acute lymphocytic leukemia was found to be caused by a dematiaceous fungus, Drechslera spicifera. The lesion was an erythematous macule that rapidly developed necrotic ulcerations. The fungus, which is commonly found in soil and as a plant pathogen, was isolated from cultures of the lesion and from an excisional biopsy specimen. Hyphae and swollen hyphal cells resembling chlamydospores were observed in the biopsy specimen. Septate pigmented hyphae were found in the tissue, which is consistent with phaeohyphomycosis. Resolution of the infection occurred following excisional biopsy and systemic amphotericin B therapy. There was a concomitant recovery from neutropenia.

In vitro evaluation of MR hypointensity in Aspergillus colonies.

PURPOSE: To demonstrate that paramagnetic elements in fungal colonies can cause hypointensity in MR images. METHODS: Aspergillus fumigatus grown in vitro was imaged with CT and MR at the time of initial inoculation and 5 days later. CT and MR images, T2 values, scanning electron microscopy, energy-dispersive analysis, and furnace atomic absorption spectrometry were performed. RESULTS: After 5 days of growth, MR images of A fumigatus revealed curvilinear hypointensities on T2-weighted images corresponding to the fungal growth. Gradient-echo images revealed two distinct components of hypointensity with different calculated T2 values. Phase-angle-difference images revealed a phase shift characteristic of magnetic-susceptibility paramagnetic effects, which corresponded to the hypointense regions on gradient-echo images. Energy-dispersive analysis and furnace atomic absorption spectrometry confirmed the presence of paramagnetic elements. CONCLUSION: It was shown that in vitro A fumigatus concentrates metal elements contained within the nutrient broth. These focal collections of calculated T2 values are caused at least partly by magnetic susceptibility effects.

Nocardia asteroides keratitis.

Nocardia asteroides has been reported as the cause of keratitis in only 7 cases and of other ocular disease in another 12 cases. We report a case of N. asteroides keratitis that presented 3 weeks after rural trauma and progressed despite trials of appropriate antibiotics. Seven weeks after the origianl injury a successful conjunctival flap was placed over the cornea. The morphology and the sensitivity testing of N. asteroides to antibiotics appears necessary before reliable information can be obtained for clinical use. Moreover, our case did not show the relatively benign course of other reported cases of nocardia keratitis.

Management of infections in patients with acute leukemia.

Several recent studies have addressed the management of infectious problems in patients with acute leukemia. Although those studies have served to emphasize the fundamental management principles formulated and proven almost 30 years ago, they have also contributed important new insights. This article describes recent developments in the management of infectious illnesses in patients who are neutropenic due to leukemia or its treatment. The discussion will focus on the increasing armamentarium of antimicrobial drugs and adjunctive agents. These expanding therapeutic options must be viewed in the context of newly emerging resistant organisms and special problems, such as the increased use of indwelling venous catheters.

Management of infectious complications of acute leukemia and antileukemia therapy.

The patient with acute leukemia is predisposed to infection by bone marrow failure that leads to absence of granulocytes, by extramedullary leukemia infiltration that leads to barrier breakdown, and by cytotoxic antileukemia therapy that exaggerates both the hematopoietic and the tissue mucosal defects. Empiric approaches tailored to treat commonly occurring bacterial and fungal infections have successfully decreased the morbidity and mortality from overwhelming infection in these compromised patients. More recently, prophylaxis directed against dissemination of pathogens from specific sites has had a positive impact in preventing the clinical and microbiological manifestations of infection during profound aplasia. The approaches that have been successful in preventing and treating bacterial infections are being applied to the increasingly prevalent fungal infections that occur later during the granulocytopenic course, with encouraging results.

Granulomatous encephalitis caused by Bipolaris hawaiiensis.

We describe a case of granulomatous encephalitis caused by Bipolaris (Drechslera) hawaiiensis in an immunocompetent patient. An 18-year-old man with a seven-month history of seizures and right leg weakness was found by computed tomographic scan to have a left frontoparietal enhancing lesion. Biopsy of the lesion revealed granulomatous inflammation and numerous septate hyphae. Culture of the biopsy specimen yielded a pure culture of B hawaiiensis in four days. Susceptibility studies revealed the organism to be sensitive to amphotericin B (minimal inhibitory concentration [MIC] equals 0.25 mg/L) and miconazole lactate (MIC equals 0.064 mg/L), but resistant to flucytosine (MIC greater than 100 mg/L). No synergy was demonstrated with amphotericin B and flucytosine in vitro. The patient was successfully treated with surgery and systemic and intrathecal amphotericin B therapy, and a negative culture was obtained from a repeated brain biopsy six weeks later.

Cell surface hydrophobicity-associated adherence of Candida dubliniensis to human buccal epithelial cells.

Microbial adherence to mucosal surfaces is an important first step in the initiation of the pathogenic process in the oral cavity. Candida albicans, the most adherent and pathogenic Candida species, utilizes a variety of mechanisms to adhere to human tissues. Although the strongest mechanism of adherence involves mannoprotein adhesins on C. albicans, cell surface hydrophobicity (CSH) plays an important role in the adherence process by providing hydrophobic interactions that turn the initial attachment between the yeast and a surface into a strong bond. Recent cell wall analytical and comparative studies showed that, Candida dubliniensis, unlike C. albicans, possesses cell surface variations that allow it to be constantly hydrophobic, regardless of growth temperature. Based on these observations, the present study was designed to compare the adherence abilities of C. dubliniensis and C. albicans to pooled human buccal epithelial cells (BEC), in regards to their cell surface hydrophobicity. Ten C. albicans and nine C. dubliniensis isolates, as well as the C. albicans hydrophobic variant A9V10 were evaluated for adherence with BEC using visual aggregation in the wells of a microtiter plate and microscopic examination. All 11 C. albicans isolates failed to show adherence to BEC, visually or microscopically, when grown at 37 degrees C. The same isolates, however, showed significant increase in aggregation and microscopic adherence to BEC when grown at 25 degrees C. All C. dubliniensis isolates tested and the A9V10 C. albicans hydrophobic variant resulted in visual aggregation and adhered to BEC when grown at either temperature. The findings from this study show that, based on comparative adherence results and growth temperature changes, C. dubliniensis seems to have greater adherence to BEC than do typical C. albicans strains and that hydrophobic interactions seem to be the mechanism of adherence involved. Although many questions remain to be answered regarding the clinical implications of this observed in vitro enhanced adherence of C. dubliniensis to human BEC, these findings support the establishment of this novel species as a clinically significant yeast.

Candida dubliniensis and Candida albicans display surface variations consistent with observed intergeneric coaggregation.

Adherence of yeasts to other microorganisms and epithelial cell surfaces is important in their colonization. Comparative studies based on the coaggregation of Candida dubliniensis versus Candida albicans with Fusobacterium nucleatum and other oral bacteria suggested differences in the surfaces of these yeasts. Transmission electron microscopy was used to test the hypothesis that there are morphologic variations in the cell surface of these two species. C. dubliniensis type strain CD36 and C. albicans ATCC 18804 were grown on Sabouraud's dextrose agar at various growth temperatures. In some experiments suspensions of yeast cells were treated with dithiothreitol. Fixation for transmission electron microscopy was accomplished using dimethylsulfoxide and alcian blue added to 3% paraformaldehyde and 1% glutaraldahyde in cacodylate buffer. The cell wall of both species was predominantly electron lucent and was visibly differentiated into several layers. A thin electron dense outer layer was seen with clearly visible fibrillar structures, closely associated to the cytoplasmic membrane. The length of the fibrils of the C. albicans cells grown at 37 degrees C was approximately two times greater than those of the cells grown at 25 degrees C. The fibrils of the 37 degrees C-grown cells were thin, distinct and tightly packed whereas those of the 25 degrees C-grown cells appeared blunt, loosely spaced and aggregated. C. dubliniensis demonstrated short, blunt fibrils appearing similar to those of the 25 degrees C-grown C. albicans cells. C. dubliniensis showed no difference in the density, length and arrangement of fibrils between the 25 degrees C and 37 degrees C growth temperatures. The shortest and most aggregated fibrils seen were of the 45 degrees C-grown C. albicans cells. Dithiothreitoltreated 37 degrees C-grown C. albicans cells revealed a distorted and partially destroyed fibrillar layer. In this investigation C. dubliniensis, unlike C. albicans, displayed an outer fibrillar layer that did not vary with variations in growth temperature. In addition, the fibrils on the C. dubliniensis cells were similar to those of the 25 degrees C-grown C. albicans in that they were considerably shorter and less dense than those of the 37 degrees C-grown C. albicans cells. It can be postulated, that C. dubliniensis exhibits constant cell surface characteristics consistent with hydrophobicity and that this property may give this species an ecological advantage. Therefore, C. dubliniensis may compete well in oral environments via enhanced attachment to oral microbes and other surfaces, perhaps even more efficiently than C. albicans.