Selective and Differential Media
Products (3)
MacConkey Agar & MacConkey III Agar
Lactose fermenters are microorganisms that ferment lactose and those that are unable to ferment lactose are called non-lactose fermenters. Escherichia coli (E. coli) are non-spore forming bacteria that are able to grow in aerobic and anaerobic conditions. Salmonella is a bacterial pathogen that can be isolated from faeces, blood, bone marrow, bile, urine, food, animal feed and environmental materials. Ingestion of contaminated food and water can cause foodborne infections, including gastroenteritis, typhoid fever, paratyphoid fever or even death in humans. All Salmonella serotypes can cause disease in humans. Acinetobacter baumannii is a Gram-negative nosocomial pathogen that can persists on dry surfaces longer than any other Gram-negative bacteria. It can persist on moist and dry surfaces for more than 20 days contributes to its widespread in a hospital setting. Acinetobacter spp. are commonly isolated from locations such as hand, groin, toe webs etc. Due to the high antibiotic resistance shown. by this bacterium an early identification is often recommended. Acinetobacter spp. have been isolated in connection with community acquired and nosocomial pneumonias, urogenital tract, eye and soft tissue infections and are difficult to treat particularly due to their broad antibiotic resistance.
TCBS Agar
TCBS (Thiosulfate-Citrate-Bile Salts-Sucrose) agar is a selective and differential medium specifically designed for the isolation and identification of Vibrio species, particularly Vibrio cholerae and Vibrio parahemolyticus. These bacteria are significant human pathogens, with epidemiological data indicating that vibriosis, the illness caused by Vibrio infections, results in an estimated 80,000 illnesses, 500 hospitalizations, and 100 deaths annually within the United States. The clinical manifestations of vibriosis are diverse and can range from mild gastrointestinal symptoms, such as diarrhea, to more severe systemic infections. These infections can include bacteremia (bloodstream infections), wound infections, and extraintestinal infections that affect other parts of the body.
XLD Agar
Xylose lysine deoxycholate (XLD) agar detects gastrointestinal pathogens, including Salmonella spp. and Shigella spp. by inhibiting gram-positive bacteria, allowing gram-negative bacteria to grow. Xylose is fermented by most enteric bacteria, producing acid that turns the medium yellow. Bacteria that decarboxylate lysine create an alkaline environment, resulting in red colonies. Salmonella spp. produces hydrogen sulfide (H2S), forming black colonies when it reacts with iron salts in the medium. XLD agar is used mainly to isolate Salmonella spp. and Shigella spp. from clinical and environmental samples, including stool. Yellow colonies indicate xylose fermentation (e.g., E. coli), red colonies show lysine decarboxylation without xylose fermentation, and black colonies suggest H2S production, typical of Salmonella spp. Further microbiological identification tests are necessary to confirm and diagnose the presence of microorganisms.