Question

A strain of Streptococcus pyogenes isolated from a throat swab was tested for sensitivity to ampicillin and tetracycline. The following results were obtained: Zone of Inhibition around ampicillin disk = 25 mm Zone of Inhibition around tetracycline disk = 21 mm Explain why the physician prescribed tetracycline instead of ampicillin. FOR FURTHER RESEARCH Most microorganisms that cause disease in humans are mesophiles. However, poorly maintained hot tubs can be a source of thermophiles that can cause human infections. List at least three species of thermophilic bacteria that can cause disease in humans.

Answer 1

Ampicillin falls under the class of Penicillins. Penicillins are the drug of choice for the treatment of infections caused by S.pyogenes. But some patients develop sensitivity towards penicillins (allergy). Since, both (ampicillin and tetracycline) the drugs exhibited fair level of sensitivity, the physician might would have prescribed tetracycline due to the sensitivity issues with ampicillin.

Three species of thermophillic bacteria ( belonging to Campylobacter genus) that can cause infections in humans are as follows:

C.jejuni

C.coli

C.lari

C.upsaliensis