Prevalence of Cryptococcus neoformans in clinical specimens

Pediatric Cryptococcosis

BACKGROUND

Seroprevalence studies have shown that 70% of children are exposed to Cryptococcus , the most common cause of meningitis in people living with human immunodeficiency virus (HIV), but reported pediatric disease prevalence is much lower than in adults.

METHODS

PubMed and Ovid Global Health databases were searched with the terms "cryptococcosis," "cryptococcal meningitis," " Cryptococcus neoformans " or " Cryptococcus gattii ." All studies reporting pediatric specific data in the English language from 1980 up until December 2022 were included.

RESULTS

One hundred sixty-eight publications were reviewed totaling 1469 children, with the majority reported from Africa (54.2%). Sixty-five percent (961) were HIV positive, 10% (147) were non-HIV immunocompromised and 19% (281) were immunocompetent. Clinical signs and symptoms were only reported for 458 children, with fever (64%), headache (55%) and vomiting (39%) being the most common. Most children (80%) suffered from meningoencephalitis. Lung involvement was rarely described in HIV-positive children (1%), but significantly more common in the non-HIV immunocompromised (36%) and immunocompetent (40%) groups ( P < 0.0001). Only 22% received the recommended antifungal combination therapy, which was significantly higher in immunocompetent children than those with HIV (39% vs. 6.8%; P < 0.0001). Overall mortality was 23%. A significant higher mortality was observed in children with HIV compared with immunocompetent children (32% vs. 16%; P < 0.001), but not compared with children with non-HIV immunosuppression (25).

CONCLUSIONS

This is the largest review of pediatric cryptococcosis with new observations on differences in clinical presentation and outcome depending on the underlying condition. The lack of granular clinical data urges prospective clinical epidemiological studies for improved insight in the epidemiology, management and outcome of cryptococcosis in children.

Primers ITS1, ITS2 and ITS4 detect the intraspecies variability in the internal transcribed spacers and 5.8S rRNA gene region in clinical isolates of fungi

Restriction fragment length polymorphism analysis of the 5.8S rRNA gene and the internal transcribed spacers (ITS1 and ITS2) was used for examination of 66 isolates belonging to 19 species. Intraspecies variability was found in the examined region of 11 species (Candida albicans, C. catenulata, C. colliculosa, C. glabrata, C. kefyr, C. melinii, C. parapsilosis, C. guillermondii, C. solanii, C. tropicalis, Saccharomyces cerevisiae). Region of ITS-5.8S rDNA was amplified using the primers ITS1 and ITS4. The amplicons were digested by HaeIII, HinfI and CfoI. The recognized intraspecies variability was confirmed in the second step, in which the shorter fragments of this region were amplified using primers ITS1 and ITS2 and analyzed by capillary electrophoresis. Considerable intraspecific variability renders this method unsuitable for species identification, whereas it can be useful for epidemiological tracing of isolates.

Candidal urinary tract infections caused by non-albicans Candida species

The incidence of non-albicans Candida and non-Candida species isolated from the urine of patients admitted to various departments of the Faculty Hospital of the Medical Faculty of Safárik University in Kosice was examined. From a total of 94 samples of analyzed urine 58 strains of C. albicans and 36 strains of yeasts belonging to 6 species of non-albicans Candida and non-Candida spp. were detected: C. parapsilosis (n = 23), C. tropicalis (6), C. krusei (3), C. robusta (2), C. catenulata (1) and Cryptococcus neoformans (1). In relation to the diagnosis, the yeasts were isolated from patients suffering from a kidneys disease, epididymitis, diabetes, neoplastic diseases, urogenital anomalies, obstructive uropathy, cystitis, prostatitis, hemolytic-uremic syndrome, and others.

Causative agents of nosocomial mycoses

In the last few years mycoses have been caused by fungi formerly considered to be harmless for humans. They cause diseases of plants and insects; some of them are also used in the industry. They are now usually called "emerging fungi". We investigated this flora with respect to their potential to cause infections in hospitals. These fungi are present in the air, on medical objects and instrumentation, in the respiratory tract and on the hands of hospital staff; other sources have been identified in the use of iatrogenic methods. Mycotic diseases, their risk factors, their clinical pictures, and spectra of agents were analyzed in 1990-2000; the results were compared with data in the literature. Transplantations were the most frequent risk factors, fungemia and abscess the most frequent clinical picture and filamentous fungi (genera Absidia, Acremonium, Alternaria, Apophysomyces, Aspergillus, Bipolaris, Cladophialophora, Cunninghamella, Exserohilum, Fusarium, Chaetomium, Chrysosporium, Lecythophora, Ochroconis, Paecilomyces, Pythium, Rhizopus, Scedosporium, Scopulariopsis) were the most frequent agents of nosocomial infections. These filamentous fungi and also some yeasts (genera Candida, Cryptococcus, Trichosporon) bring about different clinical syndromes in both immunocompromised and immunocompetent patients.

Candida species isolated from cerebrospinal fluid

In the period from November 1998 to June 2001 13 cases of nosocomial meningitis were reported. Candida albicans was isolated from 54% of the patients (7); C. parapsilosis from 23% (3); C. tropicalis from 15% (2) and C. krusei from 8% (1). C. albicans was isolated from the cerebrospinal fluid (CSF) of five children with the following diagnoses: nonspecified tumor of the central nervous system, Hodgkin's disease, meningitis, suspect neuroinfection, and sepsis. Examination of CSF allowed us to detect 2 strains of C. albicans from adult patients, one after neurosurgery because of a brain tumor and one with a vascular disease of the brain. C. parapsilosis was found in CSF from two premature children and one child with epilepsy. Two isolates of C. tropicalis were obtained from both blood and the CSF of a child from the neonatal intensive care unit and from a child from pediatric oncology with multiple malignant neoplasms. Only one strain of C. krusei was found in the oral cavity and CSF of a patient after neurosurgery performed after head trauma.

Characterization of Cryptococcus neoformans var. neoformans serotype A and A/D in samples from Egypt

The cryptococcal polysaccharide antigen was detected in 10 cerebrospinal fluid (CSF) and 23 serum samples from cryptococcal meningitis and intestinal cryptococcosis by the cryptococcal antigen latex agglutination system (CALAS). CALAS titers in CSF and serum samples of cryptococcal meningitis ranged over 8-2048 and 32-2048, respectively, while in cases of intestinal cryptococcosis, serum titers ranged over 8-2048. The isolates of yeast Cryptococcus neoformans were determined to be of serotype A or of the A/D pair. The total leukocyte count and biochemical parameters in CSF were significantly increased as indicators of microbial infection. Furthermore, the in vitro change of the teleomorph (sexual state) to the anamorph (asexual state) was also detected and the teleomorph state changed in vivo to the encapsulated anamoph state which is more virulent during infection in vivo than the yeast-like noncapsulated form. Two primers for internal transcribed spacer (ITS) regions of ribosomal DNA were used for molecular detection of C. neoformans. After PCR amplification, a DNA band of 415 bp, visualized on agarose gel, indicated the presence of C. neoformans cells in the tested CSF and serum samples. The primer sensitivity was also characterized using purified yeast chromosomal DNA as template; it was about 20 pg or more chromosomal DNA which represents about 10 cells of C. neoformans. The primers were also specific for ITS regions of C. neoformans and gave negative results with Candida albicans and E. coli chromosomal DNA templates.

Candida-associated denture stomatitis

Candida-associated denture stomatitis was demonstrated by its cultivation in 171 out of 240 patients examined with partial or total dentures. After taking smears from lesions of the oral mucosa (tongue, cheeks, palate) and the contiguous denture surface by cotton wool swabs and inoculating them onto Sabouraud glucose agar and CHROMagar Candida, individual yeast species were identified by a germ tube, filamentous, and assimilation tests employing the commercial kit AuxaColor. Seven Candida species were identified in smears from the oral mucosa lesions and the contiguous denture surface: C. albicans (95 patients), C. tropicalis (26), C. parapsilosis (20), C. krusei (14), C. guilliermondii (12), C. lusitaniae (1) and C. freyschusii (1). Diabetes mellitus, neoplastic diseases, chemotherapy, radiotherapy, and broad-spectrum antibiotic therapy were identified as some of the large number of factors predisposing patients to stomatitis prothetica.

Detection of anti-Candida antibodies in neonates from a Neonatal Intensive Care Unit

Anti-Candida antibodies were determined in a group of preterm neonates from a neonatal intensive care unit with serious diseases including candidemia. Antibodies to C. albicans blastospores, i.e. antibodies to C. albicans surface mannan and to C. albicans germ tubes were detected. Higher titers of antibodies to blastospores (1:320) occurred in all patients examined while antibodies to C. albicans germ tubes (with the highest titer of 1:160) were present in 32 out of 66 neonates examined. The highest titers of both anti-C. albicans blastospore antibodies and anti-C. albicans germ tube antibodies were detected in neonates with candidemia and disorders of saccharide metabolism.

Fungal diseases of the respiratory tract

The proportion of Candida and non-Candida species in the clinical material from patients with respiratory-tract diseases was determined. C. albicans was isolated in 102 cases. An additional 89 strains of yeasts, isolated in association with respiratory diseases, belonged to 10 non-albicans Candida spp. and Cryptococcus spp. The prevailing species, which occurred in 47 cases, was C. parapsilosis. C. tropicalis, C. glabrata, and C. guilliermondii were isolated in 12, 10, and 9 cases, respectively. Four strains of C. krusei and three strains of C. lusitaniae and one strain each of C. freyschussii, C. robusta, C. zeylanoides, and Cryptococcus neoformans were also isolated.

The frequency of Candida species in onychomycosis

Mycological investigation of 108 nail specimens taken from a total of 41 patients examined over three years included direct microscopy and repeated cultures. A higher incidence of onychomycosis of the fingernails (75%) was observed in women while afflictions of the toenails (71%) prevailed in men. The highest prevalence of onychomycosis was found in patients between 50 and 70 years of age. Candida albicans was the dominant organism causing onychomycosis (prevalence rate 60.9%), followed by C. parapsilosis (19.6%), C. tropicalis (9.8), C. krusei (4.9), C. guilliermondii and C. zeylanoides (2.4% each).

Cutaneous candidosis in immunosuppressed patients

One-hundred patients with candidosis of the skin, mucous membranes and nail plates (confirmed by cultivation) were examined. Topical or systemic antimycotic treatment was successful in 58 patients. After a complete evaluation, 42 patients were found to suffer from factors supporting candidosis--diabetes mellitus (12), anemia (3) and various local factors (10 patients); 27 patients showed a deficiency in cell-mediated immunity. In addition to intensive antimycotic therapy, successful treatment is affected by the actual immunity level and can be ensured by efficient immunomodulation treatment of immunodeficiency.

Incidence of Candida species isolated from human skin and nails: a survey

Distribution of Candida species was investigated by examining 245 samples from skin lesions and nails. The isolates were identified using standard laboratory methods including germ tube test, micromorphology of colonies on rice agar, the commercial kit, saccharide assimilation and fermentation tests. Eight species of Candida were identified: C. albicans accounted for 56.4% of the isolates, C. parapsilosis 29.1, C. tropicalis 7.8, C. pulcherrima 2.9, C. guilliermondii 1.5, C. krusei and C. zeylanoides for 0.9% each, and C. robusta for 0.5%. The factors significantly associated with colonization were prolonged antibiotic therapy, parenteral nutrition, low birth body mass of infants, intubation, duration of stay in hospital, indwelling intravenous catheter, malignancies, diabetes, surgery, and obesity.

Rare non-albicans Candida species detected in different clinical diagnoses

In working on the incidence of yeasts we excluded from the tested set C. albicans, C. krusei, C. parapsilosis and C. tropicalis on the basis of morphological and biochemical properties. We found 16 rare species of yeasts: C. claussenii (16), C. guilliermondii (10), C. robusta (9), C. pulcherrima (8), C. zeylanoides (4), C. glabrata (3), C. lusitaniae (3), C. catenulata (2), C. mesenterica (2), C. utilis (2), C. freyschussii, C. intermedia, C. kefyr, C. lipolytica, C. mogii, C. pseudotropicalis (1 for each). These yeasts were detected mainly in cases of premature babies (22) from the nasopharynx (13), from the rectum (4), from the skin (23), from wound drains and from blood (1 for each), with gynaecological diagnoses (15) and rarely other diagnoses, such as malignancy (5), hypertension and respiratory infections (4 for each), kidney transplantation (3), dialysis, haemolytic-uremic syndrome (2 for each), perforation of gastric ulcus, otitis, prostatitis, ulcus cruris, coma, spina bifida, peritonitis and hepatic failure from different clinical material.