ATCC 10231 Candida Albicans (Robin) Berkhout

In the extensive microbial culture archive maintained by the American Type Culture Collection (ATCC), very few strains have achieved the level of prevalence and usefulness of ATCC 10231. This designation refers to a specific isolate of Candida albicans (Robin) Berkhout, a dimorphic fungus that serves as the prototype of one of the most common opportunistic human pathogens. This strain has become indispensable to laboratories worldwide due to its reliability in quality control, antimicrobial susceptibility testing, and fundamental research in fungal biology. Representing the intersection of basic science and applied microbiology, ATCC 10231 continues to underpin advances in mycology, pharmacology, and clinical diagnostics.

The origins of ATCC 10231 date back to the mid-20th century, when awareness of fungal infections in immunocompromised patients increased. The strain, isolated from a clinical sample, was initially cataloged as NIH 3147 by the National Institutes of Health in the United States. It was later added to the ATCC collection, where it received its permanent name, ATCC 10231. For years, it has been cross-referenced in international data repositories.

The historical significance of this strain lies in its selection as a reference for early antifungal drug development studies. As polyene antifungal drugs emerged, ATCC 10231 provided a standard test organism, and its stability, maintained through rigorous subculture protocols, served as a shield against variability in early microbiological analyses, ensuring reproducible results.

Candida albicans ATCC 10231 exemplifies the species' distinctive dimorphism, capable of switching between yeast and hyphae forms depending on environmental factors such as temperature, pH, and nutrient availability. Genomically, ATCC 10231 is a diploid species with a genome size of approximately 28 Mb and encodes genes for virulence factors such as aspartic proteinases, which facilitate tissue invasion, and estrogen-binding proteins, which may influence host interactions.

Phenotypic variation in the strain between opaque and white blood cell types has been a focus of recent proteomic research.

ATCC 10231's versatility makes it indispensable in both academic and commercial settings.

One of its primary roles is the analysis of antifungal agents. As specified in pharmacopoeia standards, it serves as a reference strain in the evaluation of amphotericin B, nystatin, and haloprogin. The United States Pharmacopoeia (USP) and the European Pharmacopoeia recommend this method for preservative efficacy testing in pharmaceuticals and cosmetics.

In sterility testing, ATCC guidelines require that no more than five passages be taken from the original culture to prevent genetic drift. Its use in the test method defined in the ASTM E979-91 standard ensures consistent verification of media and filtration systems. Commercial products distribute lyophilized or swab versions for rapid inoculation in quality assurance laboratories.

In virulence and drug resistance studies, researchers are using ATCC 10231 to model candidiasis, which causes a variety of infections ranging from mucosal thrush to systemic spread in susceptible populations.

In industrial and environmental studies, ATCC 10231 tests food preservatives and personal care formulas for efficacy against fungal contaminants, extending beyond the medical field. It evaluates biocides in environmental microbiology, water treatment, and membrane filters. Purified genomic DNA is commercially available, facilitating molecular studies without the need for live cultures.

The enduring importance of ATCC 10231 stems from its genetic stability and phenotypic predictability, evidenced by over seventy years of study. In an era dominated by multidrug-resistant fungi, this strain is guiding global health strategies, from World Health Organization antifungal management programs to the development of next-generation vaccines.

As climate change expands the geographic range of candidiasis, strains like ATCC 10231 will remain vital for surveillance and treatment innovation.

ATCC 10231 (Candida albicans) is one of the most important reference strains in microbiology for the following key reasons:

• It is the global standard for antifungal susceptibility testing: It is the official reference strain specified in major pharmacopoeias (USP, EP) for efficacy testing of many antifungal drugs. It is also used as a quality control organism in clinical laboratories performing antifungal susceptibility testing.
• Preservative efficacy and sterility testing: Required for antimicrobial preservative efficacy testing in pharmaceuticals, cosmetics, and personal care products according to USP <51>, EP 5.1.3, and ISO 11930 standards. Used to verify the growth-promoting properties of culture media and to test sterility testing methods.
• Exceptional genetic and phenotypic stability: It has been maintained for many years through strict passage control, making it one of the most stable and reproducible Candida albicans strains available. This stability ensures that results obtained in a lab decades ago are directly comparable to those obtained today, which is critical for long-term drug development and regulatory consistency.
• It is a benchmark for virulence and resistance research: The “natural type” is widely used as a reference in studies of biofilm formation, phenotypic variation (white-opaque), hyphal morphogenesis, and azole/echinocandin resistance mechanisms. Because its complete genome is sequenced and publicly available, it has become a standard for genomic, transcriptomic, and proteomic comparisons.
• It is the industrial and regulatory gold standard: It is mandatory or recommended in numerous ASTM, ISO, and FDA guidelines for testing disinfectants, contact lens solutions, medical devices, and water systems. Commercial manufacturers sell lyophilized or ready-to-use preparations of this exact strain to quality control laboratories worldwide.

In conclusion, ATCC 10231 is the “E. coli K-12” equivalent for fungal research and testing, being the world’s most universally accepted, stable, and legally mandated single Candida albicans strain. Almost every antifungal drug, preservative, or sterility testing method approved in the last 60 years has been validated against this specific strain at some point.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the “ATCC 10231 Candida albicans (Robin) Berkhout” standard.