A new method of antibiotyping yeasts for subspecies discrimination and distribution in human clinical specimens.

A study of the antibiotypes of 764 isolates of the genera Candida and Torulopsis from different clinical specimens is reported. The typing method was based on the susceptibility results obtained by the standardized and partially automated kit ATB-Fungus (API-bioMérieux), giving to each strain a code of six figures, according to these criteria: susceptibility to 5-fluorocytosine, amphotericin B, nystatin, miconazole, econazole, and ketoconazole. Candida albicans serotypes were determined by the Candida Check test (Iatron, Japan). Twenty-six antibiotypes were found in C. albicans (482 isolates), 21 types in serotype A, and 15 in serotype B strains. Candida parapsilosis (115 isolates) was divided into 11 antibiotypes, Torulopsis glabrata (53 isolates) into five, Candida guilliermondii (36 isolates) into 10 and Candida tropicalis (31 isolates) into eight. Depending on the sample origin, 000000 (susceptibility to all the antifungals tested) was the predominant C. albicans antibiotype (92.9% of blood isolates, 41.2% of vaginal isolates, 33.3% of respiratory isolates, isolates, 31.01% or oral and digestive tract isolates, and 25.0% of nail and skin isolates). No predominant antibiotypes were found in strains from respiratory tract, skin ad nails. A reproducibility close to 99% was found with the test. Simplicity and standardization could make this method useful for typing Candida and Torulopsis isolates.

Variability in expression of antigens responsible for serotype specificity in Candida albicans.

The monoclonal antibody (mAb) B9E, which reacts with a cell wall surface determinant of Candida albicans serotype A, and a polyclonal monospecific antiserum against the antigen 6 (IF6) were used to investigate the expression of the antigens responsible for the serotype specificity in C. albicans under different growth conditions. By indirect immunofluorescence, both antibodies reacted with the cell wall surface of serotype A yeast cells and germ tubes grown in vitro but no reactivity was observed with serotype B yeast cells. In some cases, only a weak reactivity restricted to a zone close to the parent yeast cell was observed in serotype B germ tubes stained with mAb B9E. Both antibodies reacted strongly with yeast cells and germ tubes present in kidney abscesses from rabbits infected with both serotypes, but only serotype A yeast cells and germ tubes present in smears from patients with vulvovaginal candidiasis reacted with B9E and IF6 antibodies. The expression of antigens reactive with both antibodies was modulated by the pH of the environment in which the fungus was grown. Both antibodies showed a similar pattern of reactivity when studied with a spectrofluorometer. Serotype A yeast cells showed maximum reactivity when cells were grown on Sabouraud dextrose broth supplemented with yeast extract at pH 4.6. The lowest reactivity was observed in cells grown at pH 2.0. Conversely, the reactivity of serotype B yeast cells increased at alkaline pH values, the highest being in cells grown at pH values of 7.2 and 9.5.(ABSTRACT TRUNCATED AT 250 WORDS)

[Assessment of the sensitivity to antifungal agents of clinical isolates of Candida albicans serotype A and B by the ATB Fungus method]. / Evaluación de la sensibilidad a los antifúngicos de aislamientos clínicos de los serotipos A y B de Candida albicans mediante el método ATB Fungus.

BACKGROUND: Candida albicans is the most frequently species isolated in patients with candidiasis. This species may be antigenically divided in serotypes A and B, which have a different pathogenic behavior and antifungal susceptibility pattern. METHODS: The antifungal susceptibility of 443 clinical isolates from both serotypes of C. albicans to 5-fluorocytosine (5FC), amphotericin B, nystatin, econazole, miconazole and ketoconazole has been tested by means of the ATB Fungus method. RESULTS: Both serotypes showed a similar in vitro susceptibility to amphotericin B, nystatin, econazole, miconazole and ketoconazole. All the isolates were susceptible to amphotericin B and nystatin. A small number of in vitro resistant isolates were observed to azole compounds. However, serotype B was significantly more resistant than serotype A (p = 0.0001) to 5FC. CONCLUSIONS: C. albicans serotype B shows a lower susceptibility than serotype A to 5FC, an antifungal product not marketed in Spain. Serotyping of C. albicans does not offer additional information on antifungal susceptibility of clinical isolates from this species.

Characterization of Candida albicans cell wall antigens with monoclonal antibodies.

The antigenic composition of Candida albicans is very complex. In order to study the antigenic relationship between blastoconidia and germ tubes of C. albicans, we produced several monoclonal antibodies and analyzed their reactivity against cell wall antigens either in intact cells or in cells treated with dithiothreitol. Overall, four types of reactivity were found. Monoclonal antibodies 3D9 and 15C9 stained the germ tubes only when tested by indirect immunofluorescence. However, they showed a different reactivity by immunoblotting. Monoclonal antibody 3D9 reacted with antigens with molecular masses of > 200 and 180 kDa specifically expressed in the germ tube. Monoclonal antibody 15C9 reacted with antigens of 87, 50, and 34 kDa present in the germ tube extract and with antigens of 92, 50, 34, and 32 kDa present in the blastoconidium extract. The reactivity of blastoconidia treated for different times with dithiothreitol with these monoclonal antibodies was also studied by enzyme-linked immunosorbent assay. The reactivity of monoclonal antibody 3D9 did not significantly change during the cell wall extraction. However, the reactivity of monoclonal antibody 15C9 was increased for blastoconidia extracted for 60 min and decreased markedly for blastocondia extracted for 120 min. Monoclonal antibody G3B was nonreactive by indirect immunofluoresence but reacted with antigens of 47 and 38 kDa present in the germ tube extract and with an antigen of 47 kDa present in the blastoconidium extract. Monoclonal antibody B9E stained both morphological phases by indirect immunofluorescence. By immunoblotting, it reacted with antigens of > 70 kDa present in the germ tube extract and with antigens of > 63, 56, 47, and 38 kDa present in the blastoconidium extract. Based on the results presented in this study, four types of antigens are described. Type I antigens are expressed on the outermost layers of the germ tube cell wall only. Type II antigens are expressed both on the germ tube cell wall surface and within the blastoconidium cell wall. Type III antigens are found within the cell wall of both blastoconidia and germ tubes. Type IV antigens are expressed on both the blastoconidium and germ tube surface. Two types more can be hypothesized for antigens expressed on the blastoconidium cell surface and within the germ tube cell wall (type V) and for those expressed on the blastoconidium surface only (type VI).

[Microbiological study of 30 samples of heroin]. / Estudio microbiológico de 30 muestras de heroína.

In the present study, 30 samples of heroin from material seized by the police in Vizcaya from 7-1-1987 to 6-30-1988 were investigated. Bacillus spp were isolated in 19 samples (63.3%), coagulase negative staphylococci in 14 (46.6%), Aspergillus in 3 (10%) and S. aureus in one (3.33%). In addition, chemical analysis of the purity of heroin was carried out with gas chromatography. The purity of the samples ranged from 1.1% to 94.3%. No relation was found between the weight of the sample, its purity and its degree of microbiological contamination. In the microbiological study of 4 lemons used to dissolve the drug, Candida krusei was isolated from three samples, Aspergillus in two and Geotrichum in one.