microbiology an introduction 13th edition test bank

Correct Answer: D

Rationale: The correct answer is D (All of the above). All three bacteria (Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa) produce endotoxins that can lead to septic shock. Endotoxins are part of the outer membrane of Gram-negative bacteria and can trigger a strong immune response, leading to septic shock when released in large amounts. Escherichia coli and Salmonella enterica are common causes of bacterial septic shock, while Pseudomonas aeruginosa is known for its ability to produce endotoxins that contribute to severe infections and septic shock. Therefore, all three choices are correct in this context.

Correct Answer: A

Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium appears as purple-stained diplococci with pointed ends on Gram staining. S. pneumoniae is a common cause of pneumonia. It is encapsulated and has a lancet-shaped appearance, which is characteristic of the pointed ends seen in the staining. Staphylococcus aureus (B) typically appears as clusters of gram-positive cocci, not diplococci. Klebsiella pneumoniae (C) is a gram-negative rod, not a diplococci. Neisseria meningitidis (D) is a gram-negative diplococci but typically lacks the pointed ends seen in the staining of S. pneumoniae.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. This is because Pseudomonas is a Gram-negative rod, oxidase-positive, and a lactose non-fermenter. The presence of fever and chills suggests a systemic infection, which is common with Pseudomonas. Salmonella typhi, Shigella dysenteriae, and Escherimalia coli are all Gram-negative rods but are typically lactose fermenters and do not match the characteristics described in the question.

Correct Answer: A

Rationale: The correct answer is A: Streptococcus pyogenes. Rationale: 1. Gram-positive cocci in chains: S. pyogenes is a Gram-positive cocci in chains. 2. Catalase-negative: S. pyogenes is catalase-negative. 3. Beta-hemolytic: S. pyogenes exhibits beta-hemolysis. Summary of other choices: B: Streptococcus pneumoniae is alpha-hemolytic and optochin-sensitive. C: Enterococcus faecalis is catalase-negative, but not typically beta-hemolytic. D: Staphylococcus aureus is catalase-positive and coagulase-positive.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Infectious process triggers an immune response to fight off the invading pathogen. 2. The immune response can lead to inflammation, fever, and production of antibodies. 3. Hypersensitivity reactions can also occur in response to the infection. 4. Options A, B, and C are not defining features of the infectious process. Summary: Option D is correct because an infectious process typically leads to an immune response and possibly hypersensitivity reactions. Options A, B, and C are incorrect as they do not specifically relate to the immune response or hypersensitivity reactions in the context of an infectious process.