Phenotypic and genotypic characterization of unusual vaginal isolates of Candida albicans from Africa

Abstract

As expected by its global prevalence, the most frequently isolated species of yeast from vaginal swabs obtained from patients in Africa was Candida albicans, which accounted for 53 of 85 (62.4%) of the isolates from women in Madagascar and 35 of 54 (64.8%) of the culture-positive women in Angola. However, 40% of the Madagascan and 23% of the isolates from Angola, as well as two isolates obtained from one German patient, were not able to utilize the amino sugars glucosamine and N-acetylglucosamine as the sole carbon source. These isolates were able to form germ tubes but did not form chlamydospores. The correct identification as C. albicans was made possible only by using a PCR-based method of DNA fingerprinting. Only minor phenotypic and genotypic variation was observed among these strains. Whether they represent a distinct clone that is found mainly in Africa is not clear. The relevance of the amino sugar catabolic pathway in C. albicans is discussed in view of these results.

Adherence ability of Candida africana: a comparative study with Candida albicans and Candida dubliniensis

“…Unattached cells were removed from the strips by washing with 5 ml phosphate-buffered saline (PBS) solution. Subsequently, the strips were submerged in 4 ml of yeast nitrogen base (YNB) containing 50 mmol l )1 glucose and incubated over a series of time intervals (2,4,6,8,24 and 48 h) at 37°C. As negative controls, six strips were handled in an identical fashion, except that no Candida suspensions were added.…”

“…Indeed the majority of C. africana isolates were recovered from vaginal swabs suggesting an enhanced ability of these strains to cause vaginitis. 4 Many putative virulence factors can contribute to the invasiveness and pathogenicity of yeast. One of the most important of these is the ability to adhere to host tissues permitting the yeast to anchor at a site and the process of tissue colonisation to commence.…”

Phagocytosis, oxidative burst, and killing of Candida dubliniensis and Candida albicans by human neutrophils

“…Stock cultures of yeast strains used in the present study (Table 1) were kept on ceramic beads (Microbank1; PRO-LAB Diagnostics, Ontario, Canada) at 370³C. In the case of C. albicans, one reference strain (ATCC 48867) and one atypical strain (A1618) not forming chlamydospores and not utilizing the aminosugars, glucosamine and N-acetyglucosamine were tested [15]. Furthermore, eight clinical isolates of C. albicans originating from the diagnostic laboratory in Aachen were included in the study (four from sputum, three from urine, and one from blood).…”

Morphological, biochemical and molecular characterisation of the first Italian Candida africana isolate

“…Candida albicans is the most important fungal pathogen, but other species such as Candida glabrata, Candida parapsilosis and the recently described species, Candida dubliniensis, have increasingly been recognised as pathogens with a wide distribution. 1 In 1995, Tietz et al [2] recovered and studied some atypical C. albicans strains from patients in Madagascar, Angola and Germany. Subsequently, 14 of those isolates and two others from two patients in Berlin, Germany, were proposed to represent a new species within the genus Candida named Candida africana.…”