Question

Identify the microbial source for antibiotic streptomycin.
A. Streptomyces griseus
B. Streptomyces venezuelae
C. Penicillium chrysogenum
D. Staphylococcus aureus

Answer 1

Hint: Streptomycin is an antibiotic used in the treatment of a number of bacterial infections. It is useful in tuberculosis, Mycobacterium avium complex, brucellosis, endocarditis, plague, and tularemia and rat bite fever. Streptomycin was discovered in 1943 and is the safest and most effective medicine needed in the health system.

Complete answer:
Streptomyces griseus is a species of bacteria in the genus Streptomyces which is found in soil. It is gram positive bacteria and is a producer of 32 different structural types of bioactive compounds. Streptomycin was the first antibiotic reported from this bacterium in 1943.
Streptomyces venezuelae is used to prepare antibiotic chloramphenicol which is used for the treatment of eyes and ears. Chloramphenicol comes as eye drops or eye ointment and is mostly used in eye treatment.
Penicillium chrysogenum is used to prepare antibiotic penicillin which is used for the treatment of bacterial infections such as infection of middle ear, stomach, kidney, bladder, etc.
Staphylococcus aureus is used for the treatment of infections that are caused during an injury or surgery. It is non motile small round bacteria which is transmitted through air droplets and causes skin infections and lung infections.

Hence, the correct option is A. Streptomyces griseus.

Note: Streptomyces is the largest genus of the Actinobacteria which is included in family Streptomycetaceae. Streptomycetes are found in soil and in decaying vegetation. These bacteria produce spores and have earthy odor which is from the production of a volatile metabolite, geosmin.