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ABSTRACTCandida dubliniensisis a newly described species that is closely related phylogenetically to Candida albicansand that is commonly associated with oral candidiasis in human immunodeficiency virus-positive patients. Several recent studies have attempted to elucidate phenotypic and genotypic characteristics of use in separating the two species. However, results obtained with simple phenotypic tests were too variable and tests that provided more definitive data were too complex for routine use in the clinical laboratory setting. The objective of this study was to determine if reproducible identification of C. dubliniensiscould be obtained with commercial identification kits. The substrate reactivity profiles of 80 C. dubliniensisisolates were obtained by using the API 20C AUX, ID 32 C, RapID Yeast Plus, VITEK YBC, and VITEK 2 ID-YST systems. The percentages of C. dubliniensisisolates capable of assimilating or hydrolyzing each substrate were compared with the percentages from the C. albicansprofiles in each kit's database, and the results were expressed as percentC. dubliniensisand percent C. albicans. Any substrate that showed >50% difference in reactivity was considered useful in differentiating the species. In addition, assimilation of methyl-a-d-glucoside (MDG), d-trehalose (TRE), and d-xylose (XYL) by the same isolates was investigated by the traditional procedure of Wickerham and Burton (L. J. Wickerham and K. A. Burton, J. Bacteriol. 56:363–371, 1948). At 48 h (the time recommended by the manufacturer for its new database), we found that the assimilation of four carbohydrates in the API 20C AUX system could be used to distinguish the species, i.e., glycerol (GLY; 88 and 14%), XYL (0 and 88%), MDG (0 and 85%), and TRE (15 and 97%). Similarly, results with the ID 32 C system at 48 h showed that XYL (0 and 98%), MDG (0 and 98%), lactate (LAT; 0 and 96%), and TRE (30 and 96%) could be used to separate the two species. Phosphatase (PHS; 9 and 76%) and a-d-glucosidase (23 and 94%) proved to be the most useful for separation of the species in the RapID Yeast Plus system. While at 24 h the profiles obtained with the VITEK YBC system showed that MDG (10 and 95%), XYL (0 and 95%), and GLY (26 and 80%) could be used to separate the two species, at 48 h only XYL (6 and 95%) could be used to separate the two species. The most useful substrates in the VITEK 2 ID-YST system were TRE (1 and 89%), MDG (1 and 99%), LAT (4 and 98%), and PHS (83 and 1%). While the latter kit was not yet commercially available at the time of the study, it would appear to be the most valuable for the identification of C. dubliniensis. Although assimilation of MDG, TRE, and XYL proved to be the most useful for species differentiation by the majority of commercial systems, the results with these carbohydrates by the Wickerham and Burton procedure were essentially the same for both species, albeit following protracted incubation. Thus, it is the rapidity of the assimilation achieved with the commercial systems that allows the differentiation of C. dubliniensisfrom C. albicans.

The salient morphologic and physiologic characteristics of 18 isolates of Scedosporium inflatum, a newly reported human pathogen, were compared with those of the morphologically similar fungi Scedosporium apiospermum, Scopulariopsis brevicaulis, and Scopulariopsis brumptii. The formation by S. inflatum of annelloconidia in wet clumps at the apices of annellides with swollen bases was found to be the most useful characteristic in differentiating this potential pathogen.

In the spring of 1988, the largest documented US outbreak of cutaneous sporotrichosis to date occurred, with 84 cases among persons from 15 states who were exposed to Wisconsin-grown sphagnum moss used in packing evergreen tree seedlings. In New York State, 13 cases occurred among 109 forestry workers. All 13 cases occurred among 76 workers who had handled evergreen seedlings and moss (attack rate = 17%). For those exposed to evergreens and moss, the risk of infection increased as worktime exposure to moss increased (attack rates: less than 10 hours, 8%; 10-19 hours, 12%; greater than 19 hours, 33%). While environmental samples of moss from the Wisconsin supplier were negative, Sporothrix schenckii was cultured from multiple samples of the sphagnum moss obtained from one of six Pennsylvania tree nurseries, representing the nursery that was identified as the source for 79 (94%) of the moss-associated cases. Differences in tree-handling procedures at this nursery--including the use of 1- to 3-year-old moss to pack seedlings, use of a pond water source to wet the moss, use of an organic polymer gel on the seedling root system, and underground storage and longer storage of moss-packed seedlings before shipping--suggested possible explanations for the association. Efforts to prevent sporotrichosis among persons handling evergreen seedlings should include the use of alternate types of packing material (e.g., cedar wood chips or shredded paper) and protective clothing such as gloves and long-sleeved shirts.

The cellular protein profiles and malate dehydrogenases, superoxide dismutases, alkaline phosphatases, and esterases from whole cell extracts of Candida spp. were studied with polyacrylamide gel electrophoresis. We investigated isolates that differed in their ability to assimilate sucrose as the sole carbon source. The protein and enzyme patterns of Candida tropicalis and its sucrose-negative variant "Candida paratropicalis Baker, Salkin, Pincus et D'Amato" were indistinguishable. Although the cellular protein and superoxide dismutase patterns of Candida albicans and its sucrose-negative variant "Candida stellatoidea" were quite similar, differences were noted in the profiles of the other enzymes studied. In addition, the C. stellatoidea isolates were found to be separable, on the basis of their enzyme profiles, into the same two types that have been reported by Kwon-Chung et al. (K.J. Kwon-Chung, B.L. Wickes, and W.G. Merz, Infect. Immun. 56:1814-1819, 1988).

Uncertainty in identifying a dematiaceous mold from a human bronchial washing precipitated a study of Dactylaria gallopava (Cooke) Bhatt et Kendrick and its relationship to Scolecobasidium constrictum Abbott. Morphologic and physiologic studies were conducted with representative isolates and subcultures derived from the isolates used to prepare the type specimens of these two fungi, as well as a third dark mold, Ochroconis constricta (Abbott) de Hoog et von Arx. All test isolates were morphologically similar in that two-celled, cylindrical blastoconidia with a rhexolytic mode of dehiscence were the predominant and most consistent anamorphic structures. Sympodial development of the conidiophore was too variable to distinguish the isolates. Based on their morphologic similarity, we propose a new combination within the genus Dactylaria as amended by Bhatt and Kendrick, D. constricta (Abbott) Dixon et Salkin. However, D. constricta could be differentiated into two groups on the basis of physiologic tests--a subgroup in which isolates grow at 37 and 45 degrees C, give a delayed positive gelatin reaction, and are inhibited on Mycosel agar; and a second subgroup in which isolates grow on Mycosel agar and give a rapid positive gelatin reaction, but do not grow at 37 or 45 degrees C. We recommend that D. constricta be viewed as a potential pathogen when isolated from clinical specimens.

The mold Aureobasidium pullulans was isolated on several nutrient media from a splenic abscess in a patient with disseminated lymphoma. Examination of stained smears and paraffin sections revealed fungal structures characteristic of this organism. This is the first reported association of A. pullulans with an opportunistic visceral infection.

The morphological and physiological characters of an atypical Candida isolated from diverse clinical specimens are described. The colony and microscopic morphologies of the atypical Candida most closely resemble those of Candida tropicalis or of reported sucrose-negative variants of C. tropicalis. However, the atypical isolates differ from C. tropicalis by their inability to ferment sucrose or melezitose and from the sucrose-negative variants by their inability to assimilate inulin and their varied utilization of other carbon substrates.

Candida lipolytica was recovered from six patients in three different clinical centers. The index isolate caused a persistent fungemia with catheter-associated Candida thrombophlebitis, the second isolate was from a polymicrobial sinusitis, and the remaining four isolates were involved in tissue colonization. These and 20 other isolates were consistent in their morphological and physiological characteristics. All formed true hyphae and blastoconidia on cornmeal-Tween 80 agar and all assimilated glucose, glycerol, and erythritol. In a murine model of disseminated candidiasis, the index isolate that caused clinical fungemia caused no mortality and produced only two lesions on a kidney, as determined at necropsy. The nine isolates selected for in vitro antifungal susceptibility studies had intermediate susceptibilities to amphotericin B but were susceptible to ketoconazole. We conclude that C. lipolytica is a weakly virulent pathogen which may require an intravascular foreign body to cause fungemia.

In this report we attempt to explain the discrepancy between beta-glucosidase (EC 3.2.1.21) activity in Candida albicans as measured by commercial kits and that found in an experimental assay. beta-Glucosidase activity in American and Israeli isolates of C. albicans was evaluated with the API ZYM and YeastIdent systems (Analytab Products) and with experimental biochemical assays. Activity was found with whole cells and cell extracts of isolates from both sources. The greatest beta-glucosidase activity was found at pH 5.0 and with p-nitrophenyl-beta-glucopyranoside (PNP-BDG) as the substrate. In assays with beta-naphthyl-beta-D-glucopyranoside and 6-bromo-2-naphthyl-beta-D-glucopyranoside (6-Br-2-naphthyl-BDG), no enzyme activity was detected in whole cells and only limited activity was found in cell extracts of isolates from both sources. In studies with PNP-BDG at pH 5.0 and 7.5, 29 to 38% less activity was found at both pHs with American whole cells, and minor activity (20%) was found at pH 7.5 with isolates from both sources. Because assays with PNP-BDG in cell extracts of isolates from both sources showed no significant differences in activity, the more limited beta-glucosidase activity in American whole cells was most likely due to less efficient transport. Because the API ZYM system uses 6-Br-2-naphthyl-BDG as the substrate and because the substrate is buffered at pH 7.5 in the API YeastIdent kit, both systems appear to be of limited value for the detection of beta-glucosidase activity in C. albicans.

The accuracy of the new API YeastIdent system and the Flow Laboratories Uni-Yeast-Tek identification kit with an expanded data base was evaluated in comparison to the API 20C yeast identification system by three laboratories. A total of 489 test isolates were used, biased toward yeasts commonly encountered in clinical specimens. Isolates not in a system's data base were not counted in the evaluation of that system. For isolates in their data base, YeastIdent was 55% accurate and Uni-Yeast-Tek was 40% accurate. By the manufacturer's criteria of reliable identification without additional tests, both systems failed to identify many common and uncommon species. The limited number of substrates and difficulties in assessing results obtained with 11 of the API YeastIdent substrates and apparent errors in the expanded Uni-Yeast-Tek data base appeared to be major factors limiting the accuracy of these systems.

Pityrosporum pachydermatis was repeatedly isolated from portions of alopecic tissue from the thorax and ears of a black bear cub (Ursus americanus). Yeastlike cells morphologically identical with those of P. pachydermatis were observed in stained tissue sections. This is the first reported association of this yeast with a member of the family Ursidae.

Two case reports add to the rare recorded instances of infection of man and other animals by Phoma or Phoma-like molds. Phoma cava was consistently cultured from aural dermatitis of a white-tailed deer (Odocoileus virginianus), and tissue sections of the ear revealed fragments of apparent pycnidial walls, as well as many septate hyphae. In the second instance, numerous Phoma-like pycnidia occurred in and upon the hairs of a young child, in a lesion initiated by Trichophyton infection.

The growth and color change produced on dermatophyte test medium (DTM) by 25 strains of zoopathogenic fungi associated with human skin lesions were evaluated quantitatively. DTM only partially suppressed the development of nondermatophytes, with total growth in most instances comparable with that observed with dermatophytes. Whereas all dermatophytes induced a rapid color change on DTM, several nondermatophytic pathogens induced an equally intense and almost as rapid conversion. The rapidity of this color change and the colonial morphology of these forms on DTM could cause their misidentification as dermatophytes under clinical conditions.