microbiology chapter 12 test bank

Correct Answer: A

Rationale: The correct answer is A: enriched media. Enriched media contain additional nutrients such as blood to support the growth of fastidious bacteria. This allows for the cultivation of a wider range of microorganisms. General-purpose media (B) contain basic nutrients for a variety of bacteria. Reducing media (C) create anaerobic conditions, not necessarily rich in organic substances. Differential media (D) contain indicators to distinguish between different types of microorganisms, not necessarily enriched with organic substances.

Correct Answer: A

Rationale: The correct answer is A: Clostridium botulinum. This bacterium produces the botulinum neurotoxin, which causes paralysis by blocking the release of acetylcholine at neuromuscular junctions. Clostridium perfringens causes gas gangrene, not paralysis. Escherichia coli is associated with gastrointestinal infections, not paralysis. Staphylococcus aureus produces enterotoxins causing food poisoning, not paralysis. Therefore, Clostridium botulinum is the correct choice based on its well-known association with paralysis due to botulinum neurotoxin production.

Correct Answer: C

Rationale: The correct answer is C because Parvovirus B19 causes erythema infectiosum, also known as fifth disease. This virus primarily affects children and causes a distinctive red rash on the cheeks, arms, and legs. It is not associated with causing HBV (Hepatitis B Virus), AIDS, or measles. Parvovirus B19 specifically targets red blood cell precursors, leading to anemia in some cases. Understanding the characteristic clinical presentation and pathophysiology of the virus helps in selecting the correct answer.

Correct Answer: D

Rationale: The correct answer is D: LT enterotoxin. This toxin is specific for Enterotoxigenic E. coli (ETEC) and is responsible for causing diarrhea by increasing cyclic AMP levels in intestinal cells. TSST-1 (choice A) is produced by Staphylococcus aureus, not ETEC. Shiga-like toxin (choice B) is produced by Shigella and EHEC, not ETEC. Erythrogenic toxin (choice C) is produced by Streptococcus pyogenes, not ETEC. Therefore, the LT enterotoxin is the specific toxin associated with ETEC.

Correct Answer: A

Rationale: The correct answer is A: Antibiotic. Brucellosis is a bacterial infection, and antibiotics are the primary treatment to target and eliminate the bacteria causing the disease. Antibiotics such as doxycycline and rifampin are commonly used for brucellosis treatment. Donor immunoglobulin (B) is not used to treat brucellosis as it is not caused by a deficiency in antibodies. Inactivated therapeutic vaccine (C) is used for prevention, not for treating active infections. Antitoxic serum (D) is used to neutralize toxins produced by bacteria, not to directly kill the bacteria themselves in cases like brucellosis.