microbiology chapter 12 test bank

Correct Answer: B

Rationale: The correct answer is B: halophiles. Halophiles are bacteria that thrive in high salt environments. They have adapted to survive and grow in areas with high salt concentrations. This preference for high salt levels is what distinguishes halophiles from other types of bacteria. A: Calciphiles are bacteria that prefer high levels of calcium. C: Osmophiles are bacteria that thrive in environments with high sugar concentrations. D: Mesophiles are bacteria that prefer moderate temperature ranges for growth. In summary, the correct term for bacteria that prefer high levels of salt in their growing environment is halophiles, making choices A, C, and D incorrect in this context.

Correct Answer: B

Rationale: The correct answer is B: abiogenesis. Spontaneous generation refers to the idea that living organisms can arise from non-living matter, which was disproven by Louis Pasteur. Abiogenesis specifically refers to the origin of life from non-living matter, making it synonymous with spontaneous generation. Biogenesis (A) is the principle that living organisms only come from other living organisms. Evolution (C) is the process of gradual change in species over time. Spontaneity (D) refers to happening without external cause and is not directly related to the concept of spontaneous generation.

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: Klebsiella pneumoniae. This bacterium is commonly associated with pneumonia in elderly patients. Klebsiella pneumoniae is a Gram-negative, non-motile, rod-shaped bacterium that frequently causes pneumonia in individuals with underlying health conditions. It is known for its ability to produce a distinctive mucoid capsule. Pseudomonas aeruginosa (B) is more commonly associated with hospital-acquired infections, particularly in immunocompromised individuals. Escherichia coli (C) is a common cause of urinary tract infections but is less likely in this case due to the symptoms and sputum sample results. Haemophilus influenzae (D) is another common respiratory pathogen, but in this scenario, Klebsiella pneumoniae is the most likely causative agent based on the patient's age, symptoms, and the characteristics of the bacteria described in the sputum sample.

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.