Vegetative Bacteria
Staphylococcus epidermidis: a gram-positive bacterium commonly used as a surrogate for Staph Aureus (MRSA) which poses infection risks in hospital environments.
Escherichia coli: a gram-negative bacterium commonly used as a surrogate for more dangerous strains of E. Coli which poses significant threats to food and hand contamination.
Pantoea agglomerans: a gram-negative bacterium commonly used as a surrogate for Yersinia pestis which causes infections such as bubonic plague.
Salmonella typhimurium: a gram-negative bacterium which serves as a surrogate for more dangerous strains of Salmonella such as Salmonella enterica which poses a threat to food contamination
Klebsiella aerogenes (formerly known as Enterobacter aerogenes): is a type of Gram-negative, rod-shaped bacterium commonly found in the human intestinal tract, soil, water, and dairy products. It's a facultative anaerobe, meaning it can grow in both the presence and absence of oxygen. While it's part of the normal gut flora in humans and animals, it can cause opportunistic infections, particularly in hospital settings or among people with weakened immune systems.
Mycobacterium smegmatis: is a type of non-pathogenic, fast-growing mycobacterium. It is rod-shaped and characterized by a high lipid content in its cell wall, a trait it shares with other members of the Mycobacterium genus, including the notorious Mycobacterium tuberculosis, the causative agent of tuberculosis.
Viruses
MS2 Bacteriophage: is a well-characterized, non-enveloped RNA virus that infects specific strains of the bacterium Escherichia coli. Belonging to the family Leviviridae, MS2 is among the smallest and simplest bacteriophages known, with a diameter of about 27 nanometers. It has a spherical shape and contains a single-stranded RNA genome. MS2 is a commonly used BSL1 surrogate for Influenza and SARS-CoV-2.
Phi-X174 Bacteriophage (φX174): is a small, icosahedral, single-stranded DNA bacteriophage that infects certain strains of the bacterium Escherichia coli. It is one of the most extensively studied bacteriophages and holds historical significance in molecular biology. Phi-X174 was the first DNA-based genome to be sequenced completely, a milestone achieved by Frederick Sanger and his team in 1977. Phi-X174 is a commonly used BSL1 surrogate for Herpes simplex and HIV.
Phi-6 Bacteriophage: is a spherical, enveloped, double-stranded RNA bacteriophage that infects the bacterium Pseudomonas syringae. It is notable for its distinctive layered structure, consisting of a nucleocapsid enclosed within a lipid envelope, which is somewhat rare among bacteriophages. Its enveloped nature also makes it a valuable model for studying viruses that possess lipid envelopes, a feature common to many human pathogens such as Ebola.
Endospores & Fungi
Bacillus globigii (now reclassified as Bacillus atrophaeus): is a species of gram-positive, rod-shaped bacteria, closely related to Bacillus subtilis. It forms highly resistant spores, allowing it to survive in harsh environmental conditions. Historically, B. globigii has been used extensively as a simulant in biological warfare studies due to its non-pathogenic nature to humans, making it a safe surrogate for more harmful biological agents like anthrax. In contemporary applications, it is commonly employed in validation studies for sterilization processes, air filtration, and biodecontamination, particularly because its spores' resistance to physical and chemical agents resembles those of many pathogenic biothreat agents.
Aspergillus niger: is a common species of fungus, known for its ubiquitous presence in the environment and its distinctive black spore-producing colonies. It is a type of mold that thrives in various substrates, ranging from soil and plant debris to indoor environments, often found in damp conditions or decaying organic matter. However, it is also known as a potential indoor air contaminant and can be a cause of health concerns, particularly in immunocompromised individuals, where it may lead to respiratory issues like allergic reactions and infections. In bioaerosol and air quality testing, Aspergillus niger serves as an important indicator species for fungal contamination and is often used in assessing the efficacy of air filtration systems, antimicrobial surfaces, and various environmental control measures.
Candida albicans: is a yeast-like fungus that is a common member of the human body's normal flora, typically found in the oral cavity, gastrointestinal tract, and vaginal mucosa. Under normal circumstances, it exists harmlessly in balance with other microorganisms, but it can cause opportunistic infections if the host's immune system is compromised or if the normal microbial balance is disturbed. C. albicans is the most significant and well-studied species among the Candida genus, notorious for causing candidiasis, which can range from superficial infections like oral thrush and vaginitis to systemic and potentially life-threatening diseases, especially in immunocompromised individuals.
This list however is not comprehensive if the surrogate you require is not listed contact ARE Labs and one of our scientists can help find a surrogate species that will meet the requirements of your testing needs and ensure that these surrogates are widely accepted for 3rd party validation testing as well as regulatory testing requirements.