Which bacteria produce endotoxins that can cause septic shock?

Correct Answer: D

Rationale: The correct answer is D. Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa all produce endotoxins that can lead to septic shock. Endotoxins are part of the outer membrane of Gram-negative bacteria and can trigger a systemic inflammatory response if released into the bloodstream. E. coli and Salmonella are common causes of bacterial infections that can lead to septic shock, while P. aeruginosa is a known opportunistic pathogen that can produce endotoxins. Therefore, all three bacteria can cause septic shock by releasing endotoxins. Choices A, B, and C are incorrect because each of these bacteria individually can produce endotoxins that contribute to the development of septic shock.

Correct Answer: A

Rationale: The correct answer is A: Spores. The Ozheshko method is used to stain spores, which are resistant structures produced by certain bacterial species. By studying the smear of streptobacillus preparation under oil immersion, one can observe the presence of spores as distinct, oval bodies within the bacteria. Spores are important for bacterial survival in harsh conditions. Summary: B: Capsules are not typically stained using the Ozheshko method. Capsules are usually visualized using negative staining techniques. C: Flagella are not stained by the Ozheshko method. Flagella are visualized using special staining techniques like the flagella stain. D: Inclusions are not specifically stained by the Ozheshko method. Inclusions are often observed using techniques that highlight cellular structures or components.

Correct Answer: C

Rationale: The correct answer is C: Fungi. Molds are a type of fungi, which are eukaryotic organisms characterized by having cell walls made of chitin. Fungi are distinct from protozoans (single-celled eukaryotes), archaea (prokaryotes), and algae (photosynthetic eukaryotes). Fungi, including molds, obtain nutrients through absorption and play crucial roles in decomposition and nutrient cycling. Therefore, molds belong to the group of eukaryotic organisms known as fungi.

Correct Answer: C

Rationale: The primary target of beta-lactam antibiotics is cell wall synthesis. These antibiotics inhibit enzymes called penicillin-binding proteins, which are essential for building the bacterial cell wall. By disrupting cell wall synthesis, beta-lactam antibiotics weaken the cell wall, leading to bacterial cell lysis and death. Protein synthesis (Choice A), DNA replication (Choice B), and folic acid synthesis (Choice D) are not directly targeted by beta-lactam antibiotics, making them incorrect choices.

Correct Answer: B

Rationale: The correct answer is B: presence of metachromatic granules. This is because Corynebacterium diphtheriae is known for containing metachromatic granules, which are characteristic of this species. These granules can be observed under a microscope and aid in the identification of the bacteria. Explanation of other choices: A: formation of spores - Corynebacterium diphtheriae does not form spores. Spore formation is more commonly seen in bacteria such as Bacillus and Clostridium species. C: production of coagulase - Coagulase production is a characteristic of Staphylococcus aureus, not Corynebacterium diphtheriae. D: beta-hemolysis on blood agar - Corynebacterium diphtheriae does not exhibit beta-hemolysis on blood agar. This type of hemolysis is more typical of Streptococcus pyogenes.