A Gram-Positive Bacillus, Which Is Beta-Hemolytic on 5% Sheep Blood

question 10

Multiple Choice

A gram-positive Bacillus, which is beta-hemolytic on 5% sheep blood agar, produces a wide zone of lecithinase on egg yolk agar, is nonmotile, and was isolated from the stool of a patient with abdominal pain and watery diarrhea.Because of the patient's existing immunocompromised state, the physician administered penicillin as the antibiotic therapy.The patient's condition did not improve after 7 days of treatment.Which one of the following statements explains the reason for the antibiotic failure?

• A) The course was too abbreviated and should be given for 14 days.
• B) The patient may be allergic to penicillin and its therapeutic effects.
• C) Penicillin is ineffective against gram-positive organisms.
• D) The organism produces beta-lactamase, which renders the drug inactive.

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Definitions:

Molecular Orbital

A region in a molecule where electrons are most likely to be found; it represents the wave-like behavior of electrons in molecules.

Atomic Orbitals

Mathematical expressions that characterize the wave-like patterns of electrons within an atom.

Orbitals

Mathematical functions that describe the wave-like behavior of electrons in atoms, important for understanding the chemical bonding of atoms.

Mathematical Description

The use of mathematical symbols and formulas to represent and solve real-world problems or theoretical concepts.