The brown colour effect (BCE) of Cryptococcus neoformans in the diagnosis, control and epidemiology of C. neoformans infections in AIDS patients

Cryptococcus neoformans was found as the causative agent of cryptococcosis in 7 (3.6%) out of 195 HIV-positive persons, most of them being hospitalized. These 7 persons included 6 homosexuals and 1 heroin addict. The examinations were performed at the Mycology Unit of the Robert Koch Institute in Berlin (West) between 1984 and 1986. The brown colour effect (BCE) of the C. neoformans colonies on Guizotia abyssinica creatinine agar (with 0.1% glucose) within 2-5 days at 26 degrees C facilitated the diagnosis of disseminated cryptococcosis. In all 7 cryptococcosis cases, the antigen of C. neoformans was detected in serum and CSF by the latex agglutination test. The initial titres ranged from 1:100,000 to 1:160 in the serum and from 1:1280 to 1:10 in the CSF. In comparison to the progressive stage of the infection with the involvement of the various organs and high antigen titres, the fungus may be detected at an early stage in the respiratory tract only where low antigen titres are observed. All the C. neoformans isolates were found to belong to the variety neoformans. Proposals for an effective control of cryptococcosis are made.

Failure of the Bactec 460 radiometer to detect Cryptococcus neoformans fungemia in an AIDS patient

Cryptococcus neoformans fungemia occurred in a patient with the acquired immunodeficiency syndrome (AIDS). The BACTEC 460 radiometer failed to detect Cryptococcus neoformans in eight aerobic BACTEC 6B culture bottles inoculated with the patient's blood. The diagnosis of cryptococcemia was established by terminal (seven-day) subculturing of 6B broth to chocolate agar, which was positive for all eight radiometrically negative blood culture bottles. It appears that radiometric measurement is not optimal for the laboratory detection of cryptococcal fungemia.

Cryptococcus neoformans var. gattii in Australia

An examination of 45 clinical isolates of Cryptococcus neoformans revealed an unusually high incidence of C. neoformans var. gattii in South Australia (65%) and in the Northern Territory (95%). In assessing all the available data from Australian isolates of C. neoformans, there appeared to be an endemic focus for the incidence of C. neoformans var. gattii in the rural aboriginal population of the Northern Territory.

Evaluation of SOC for the presumptive identification of Candida albicans and Cryptococcus neoformans

SOC, a fungal growth medium composed of Solryth, oxgall, and caffeic acid, was evaluated as a medium to provide rapid, differential identification of Candida albicans and Cryptococcus neoformans. Using a variety of common isolation media to produce the yeast inocula, the germ tube methods tested ranked in the following order of decreasing sensitivity: SOC (97% +/- 1), serum (92% +/- 5), rabbit coagulase plasma with EDTA in combination with tryptic soy broth (89% +/- 5), TOC (89% +/- 6), and rabbit coagulase plasma with EDTA (83% +/- 4). In chlamydospore production, SOC also proved to be the most sensitive after 24 h incubation: SOC (96% +/- 2), TOC (80% +/- 2), and cornmeal-Tween 80 agar (14% +/- 3). Other medically important yeasts showed normal patterns of growth within 24 h on SOC, thus assisting in their identification. Eighty strains of Cryptococcus neoformans showed characteristic brown pigmentation on SOC and TOC within 18 h, while all other species of the genus Cryptococcus and 229 Candida isolates did not show a change in pigmentation.

In vivo and in vitro studies with an atypical, rhinotropic isolate of Cryptococcus neoformans

An atypical isolate of Cryptococcus neoformans was investigated because of its consistent and reproducible production of gross nasal pathology following i.v. injection in Swiss albino mice. Dose response to graded concentrations ranging from 1 X 10(2)-1 X 10(7) cells/mouse yielded an LD50 of 1.4 X 10(3) cells/mouse for the atypical rhinotropic strain H140 which was significantly less virulent (p less than 0.01) than our reference strain of Cryptococcus neoformans. There was no significant difference in mortality following the injection of in vitro vs. in vivo passed inoculum. As early as two weeks after inoculation, this strain produced gross nasal enlargement to approximately 2-3 X normal dimensions with granulomatous and ulcerated lesions. The LD60 resulted in the greatest percentage of nasal involvement (85%). C. neoformans was demonstrated by culture and histopathology in the noses, brains, lungs, livers and kidneys. A temperature selection was indicated by findings of a lower temperature minimum for subcultures isolated from the noses relative to those isolated from the brain, and by the fact that the most densely populated organs following intraperitoneal injection were the testes. This route of inoculation resulted in cutaneous nasal involvement in a manner analogous to that following i.v. injection. The atypical isolate was unable to assimilate trehalose or raffinose but otherwise was entirely consistent with identification as C. neoformans and produced characteristic CNS and general organ system disease in addition to the rhinotropic cutaneous manifestations. The model characterized here in normal mice may be of value in studies of fungal dermotropism.

Bronchoalveolar lavage as the exclusive diagnostic modality for Pneumocystis carinii pneumonia. A prospective study among patients with acquired immunodeficiency syndrome

Pneumocystis carinii pneumonia (PCP) is the most common life-threatening opportunistic infection among patients with the acquired immunodeficiency syndrome (AIDS). Because retrospective studies suggested that bronchoalveolar lavage (BAL) compared favorably to lung biopsy in the diagnosis of PCP, we prospectively evaluated the utility of BAL in 40 consecutive patients with AIDS or risk of AIDS who presented with respiratory complaints. The BAL revealed P carinii in 36 of 42 episodes of pneumonia (86 percent) among 40 patients. Clinical follow-up of the six patients whose BAL was negative for PCP suggested only one possible false negative BAL for PCP. Therefore, BAL detected PCP in 36 of 37 patients for a sensitivity of 97 percent. BAL detected cytomegalovirus in 15 of 38 patients, as well as Mycobacterium avium-intracellulare and Cryptococcus (each in one patient). By virtue of accuracy and lack of morbidity demonstrated in our study, BAL should supplant lung biopsy techniques in the evaluation of AIDS patients with pulmonary symptoms.

Mycobacteria and cryptococci cultured from the buffy coat of AIDS patients prior to symptomatology: a rationale for early therapy

Culture of the buffy coat layer of the peripheral blood of 14 AIDS patients demonstrated sustained mycobacteremia or fungemia: 11 with Mycobacterium avium-intracellulare, 2 with Cryptococcus neoformans, and one with Mycobacterium tuberculosis. The early detection of these agents prior to the onset of overt symptomatology of disseminated infection due to these microorganisms allowed speculations on an early phase bacteremia and the proposal of prompt inception of antimicrobial therapy while the microbial burden is still manageable. The method also obviates the need for more invasive techniques.

Isolation of highly encapsulated Cryptococcus neoformans serotype B from a patient in New York City

For the first time, Cryptococcus neoformans serotype B was isolated from a patient in New York City, not a region endemic for B/C serotypes. The isolate was morphologically unusual, with cells several times larger in infected tissue than those characteristic of the yeastlike pathogen. This anomaly may be a problem in the identification of similar isolates. Two serotype differentiation media and a slide agglutination test were used for definitive serotype identification.

Poorly encapsulated Cryptococcus neoformans from patients with AIDS. I: Preliminary observations

Ten isolates of Cryptococcus neoformans recovered from individual patients with the acquired immunodeficiency syndrome (AIDS) were studied in conjunction with three other isolates from non-AIDS patients. On primary culture nine out of ten of the AIDS isolates grew as nonmucoid, dry, pasty colonies resembling those produced by "diphtheroids." One isolate formed moist colonies. In contrast, the three non-AIDS Cryptococcus neoformans isolates produced highly mucoid colonies. India ink mounts of primary cultures of the ten AIDS isolates after 48 hours incubation in 5% CO2 showed markedly smaller capsules than the three non-AIDS isolates. India ink preparations of fresh cerebrospinal fluid of two specimens from AIDS patients in which capsule sizes were systematically determined showed a few moderately encapsulated cells dispersed among numerous others that were poorly encapsulated. This observation was confirmed in mucicarmine-stained smears of cerebrospinal fluid. Poorly encapsulated Cryptococcus neoformans seem to be associated with infections in AIDS patients.

Large Cryptococcus neoformans isolated from brain abscess

Cryptococcus neoformans yeast cells 40 to 60 micron in diameter were seen in an India ink preparation made from a human brain abscess specimen. In culture at 25 degrees C, uniform 5-micron-diameter yeast cells were produced. Inoculation into mice produced yeast cells up to 40 micron in diameter, and brain heart infusion broth culture at 35 degrees C produced yeast cells about 25 micron in diameter. A relationship of yeast cell diameter to incubation temperature is suggested.

A Cryptococcus neoformans strain from the brain of a wildlife fox (Vulpes vulpes) suspected of rabies: mycological observations and comments

A Cryptococcus neoformans strain which in 1983 caused an infection of the central nervous system (CNS) in a wildlife fox with rabies-like symptoms was tested for its strain-specific brown colour effect (BCE) on Guizotia abyssinica creatinine agar and for its ability to assimilate creatinine. Both reactions were found to be positive. These results were found to be largely identical with those of 2 out of 3 strains having caused fatal cryptococcosis in 1970, 1979 and 1983 in persons living in the area where the fox had been found (radius 40-100 km). Some theoretical aspects of the epidemiology and pathogenesis of cryptococcosis in the wildlife fox and rodents are discussed. For further epidemiological investigations into the prevalence of Cr. neoformans in man and animals in this area, the two reactions for detecting and typing, i.e. the BCE on Guizotia abyssinica creatinine agar and the creatinine assimilation are proposed.

Sampling and isolation of Cryptococcus neoformans from indoor air with the aid of the Reuter Centrifugal Sampler (RCS) and guizotia abyssinica creatinine agar. A contribution to the mycological-epidemiological control of Cr. neoformans in the fecal matter of caged birds

In February and March 1984, Cryptococcus neoformans was detected in the manure and ambient air of a volery in the Berlin Zoo in which a Palm Cockatoo (Probosciger aterrimus) was kept. Both times, 5 colony-forming units of Cr. neoformans could be isolated on the differential medium, Guizotia abyssinica creatinine agar, from 40 1 of air aspirated by the Reuter Centrifugal Sampler (RCS). The absence of a concurrent growth of moulds was found to be of special importance for the optimal isolation of Cr. neoformans on the above mentioned agar for purposes of epidemiological research into airborne dissemination of the fungus. The advantages and disadvantages of 0.1% biphenyl to inhibit concurring growth of moulds are discussed. The control of habitats and foci of Cr. neoformans in zoos and similar establishments is considered a necessity, to prevent inhalatory exposure of susceptible, e.g. immuno-compromised persons.

Pulmonary cryptococcosis

Observation of an unusual pulmonary distribution of cryptococci in a patient at autopsy prompted a review of 36 patients with pulmonary cryptococcosis listed in the autopsy files of The Johns Hopkins Hospital. The patients ranged in age from 2 to 89 years (mean, 49 years), 19 were female, and 18 were black. All but three patients had underlying debilitating diseases, and 23 patients had received steroids and/or chemotherapy. In 25 patients (69 per cent) cryptococcosis was a major factor contributing to death, through pulmonary disease in ten, systemic involvement in seven, and central nervous system disease in eight. In 15 patients (42 per cent) cryptococcosis was diagnosed clinically. Four basic morphologic patterns were observed: 1) Seven patients (19 per cent) had one or more peripheral pulmonary granulomas. In three of these patients the granulomas were apparently quiescent, and no other lesions were found. 2) Nineteen patients (53 per cent) had what has been called granulomatous pneumonia, with intra-alveolar proliferating organisms and varying degrees of inflammatory response, which, when present, ranged from acute inflammation to diffuse intra-alveolar granulomas with giant cells. 3) In seven patients (19 per cent) organisms were present diffusely within alveolar capillaries and interstitial tissues, and reactions ranged from little or no inflammation with numerous organisms to few organisms with miliary granulomas. 4) In three patients (8 per cent) both intra-alveolar and intravascular organisms were present in massive numbers, and the primary route of infection was uncertain. Fatalities from pulmonary and generalized infection occurred in patients in each histologic group. The results show marked variability both in pathologic reaction to cryptococci and in the clinical appreciation and significance of pulmonary cryptococcosis.

High prevalence of Cryptococcus neoformans var. gattii in tropical and subtropical regions

The global distribution of 96 clinical isolates of Cryptococcus neoformans var. gattii among a total of 725 C. neoformans isolates was investigated. While C. neoformans var. gattii was not found among isolates obtained from Europe (excluding the United Kingdom) and Japan; and it was found only infrequently in North America (excluding Southern California), the United Kingdom, New Zealand, and Argentina; the variety was prevalent in regions with tropical to subtropical climates such as South East Asia, Southern California, Brazil, Mid to South Pacific, and the central part of Africa. Among the isolates of C. neoformans var. gattii in our collection, serotype B predominanted (77 of 96), and the serotype C isolates were almost exclusively from North America.

Benign cryptococcaemia

The most familiar clinical presentation of cryptococcal disease is subacute lymphocytic meningitis, generally in immunocompromised patients. Isolation of Cryptococcus neoformans from the bloodstream has been regarded as a grave prognostic sign, but we have recently seen a patient with cryptococcaemia which had an unusually benign course.

Comparison of the sensitivity of three methods for the rapid identification of Cryptococcus neoformans

The sensitivity of three methods for the rapid identification of Cryptococcus neoformans was compared. These were: direct microscopy of india ink preparations, acridine orange staining followed by fluorescence microscopy and detection of cryptococcal capsular polysaccharide antigen by latex agglutination. The overall limit of detection was 3.5 +/- 5.4 X 10(3) CFU/ml (mean +/- SD, n = 27). When different strains were studied, no single method was consistently superior. False positive results were rare (two of 162 observations, 1.2%) but there were eight false negatives (4.9%), five of which were with acridine orange. Tests such as these are an invaluable aid in the rapid diagnosis of cryptococcal meningitis but they cannot be relied upon to detect low grade infections.