With a little ignorance, a strep throat containing bacteria Streptococcus pyogenes or Strep A can develop into a flesh-eating bacterium that can take breaths of lakhs of people around the globe every year majorly from low- & middle-income countries. In the year 2019, an outbreak of Strep A in Essex, England killed 13 people and infected 35. These numbers have thus created an urgent need for making the mankind more aware about preventing this deadly disease.
Strep A is usually spread by being in direct contact with the infected person or indirectly by touching any object with Strep A. They initially infect the humans by causing inflammation of the throat and tonsils and if not treated, can result into scarlet fever, acute rheumatic fever and damaging of the heart valves. Some of the preliminary steps to control the spread of Strep A infection are hygienic hand washing after coughing and sneezing & before and after cooking meals. If a person has a sore throat- he should visit a physician as early as possible. The physician would recommend for the immediate diagnosis with a swab tests on Blood Agar medium.
Sheep Blood Agar plates are the right medium for culturing this bacterium in its early stage itself. They are most helpful for the world to fight away the pathogen before it can take a life.
Streptococcus spp. being a fastidious microbe needs special enriched media for its growth. Sheep Blood Agar plates has defibrinated 5% sheep blood, isolated from an antibiotic- free animal that provides the perfect combination of nutrition to them. Under anaerobic conditions, the growth of Streptococci can be visualized by the β (beta) haemolytic reactions around the colonies where the cherry-red coloured agar turns colourless. This clear zone around the colonies indicates the lysis of the RBCs by Streptococcus pyogenes which produces haemolysin as an exotoxin.
Other than β (beta) –haemolysis, there are two more types of Haemolytic reactions- α (alpha) & γ (gamma) and these can vary from microbe to microbe. In α- haemolysis, the discoloration of greenish colour occurs around colonies whereas in γ- lysis, no lysis of blood and apparently no colour change is observed in the blood agar plates.
Sheep Blood Agar plates also play another important role in the diagnosis of Strep A infection. The plates can be helpful for determination of the pathogen’s sensitivity to Bacitracin drug. The clinicians consider this sensitivity test, a mandatory step before advising any line of treatment.
TM Media offers a range of blood agar bases for the specific isolation of fastidious organisms such as Staphylococci, Pneumococci, Bordetella pertussis, Corynebacterium, Streptococcus pneumoniae. A modified plate Sheep blood agar base (TMP 018) is specifically formulated to diagnose the toxin producing Bacillus cereus bacteria from the food samples. This Bacillus spp. are known to cause food poisoning, when ingested along with food.
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