Which of the following bacteria is associated with Lyme disease?

Correct Answer: A

Rationale: The correct answer is A: Borrelia burgdorferi. This bacterium is associated with Lyme disease, a tick-borne illness. Borrelia burgdorferi is transmitted to humans through the bite of infected black-legged ticks. It causes a range of symptoms, including fever, rash, joint pain, and neurological problems. Summary: B: Clostridium botulinum is associated with botulism, a serious illness caused by a toxin produced by this bacterium. C: Escherichia coli is a common bacterium found in the intestines of humans and animals, some strains can cause food poisoning. D: Streptococcus pneumoniae is a bacterium that can cause pneumonia and other respiratory infections, but not Lyme disease.

Correct Answer: B

Rationale: The correct answer is B: Protein synthesis. Bacterial ribosomes are responsible for translating the genetic information from mRNA into proteins. This process involves the binding of transfer RNA molecules carrying amino acids to the ribosome and the formation of peptide bonds between the amino acids to create proteins. DNA replication (A) is carried out by DNA polymerase enzymes, not ribosomes. Energy production (C) is primarily the function of mitochondria in eukaryotic cells, and cell division (D) is regulated by a complex network of proteins and signaling pathways, not ribosomes.

Correct Answer: C

Rationale: The correct answer is C because coagulase helps bacteria like Staphylococcus aureus to form clots, allowing them to evade the host immune response. This mechanism helps the bacteria to hide from the immune system and establish infection. A. Adhesion to surfaces is usually facilitated by other factors like adhesins. B. Breaking down red blood cells is not a function of coagulase. D. Antibiotic resistance is typically mediated by other mechanisms like efflux pumps or enzymatic inactivation, not coagulase.

Correct Answer: A

Rationale: The correct answer is A: Spores. In the Ozheshko staining method, spores appear blue with red terminal components. Spores are reproductive structures produced by some bacteria, fungi, and protozoa. Cilia are short, hair-like structures used for movement. Flagella are long, whip-like structures also used for movement. Capsules are outer protective layers surrounding some bacteria. In this case, the description of rod-like microorganisms with blue staining and red terminal components aligns with the characteristics of spores, making it the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Rifampicin. Rifampicin is known to cause red discoloration of bodily fluids, including tears and urine, due to its side effect of harmless color changes. Benzylpenicillins (B and C) and Biseptol-480 do not typically cause such discoloration. Rifampicin's mechanism of action involves binding to bacterial RNA polymerase, leading to inhibition of RNA synthesis, which is unrelated to the mechanism of the other drugs. Thus, based on the unique side effect profile of Rifampicin and its mechanism of action, it is the most likely drug causing red tears and urine in this scenario.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is known for producing a bluish-green pigment called pyocyanin, which presents as a cyan pigment. This bacterium is commonly associated with wound infections and is often found in oral surgery complications. Proteus vulgaris (B) and Klebsiella pneumoniae (D) are not typically associated with cyan pigment production, making them less likely causative agents. Bacillus subtilis (C) is not known to produce cyan pigment and is not a common pathogen in wound infections. Therefore, based on the presence of cyan pigment and the clinical context of an oral surgery complication, Pseudomonas aeruginosa is the most probable causative agent.

Correct Answer: A

Rationale: The correct answer is A: Salmonella enterica. This is because Salmonella are Gram-negative rods that do not ferment lactose, which fits the description in the question. Additionally, Salmonella is a common cause of severe abdominal pain and diarrhea. Shigella dysenteriae is a Gram-negative rod that also causes severe diarrhea but it does not share the characteristic of not fermenting lactose. Escherichia coli is a Gram-negative rod that does ferment lactose. Proteus vulgaris is also a Gram-negative rod but it is not commonly associated with severe abdominal pain and diarrhea, making it an unlikely causative agent in this scenario.

Correct Answer: D

Rationale: Certainly! The correct answer is D: Pertussis exotoxin. Pertussis toxin primarily affects the respiratory system causing whooping cough. It does not directly target the nervous system like the other toxins listed. Tetanospasmin causes muscle spasms, Diphtheria exotoxin affects the heart and nerves, and Botulinum exotoxin causes paralysis by blocking neurotransmitter release. Therefore, Pertussis exotoxin is the only toxin among the options that does not manifest with neurological symptoms.

Correct Answer: A

Rationale: The correct answer is A: Botulism. The tennis racket appearance seen under the microscope is characteristic of Clostridium botulinum, the bacterium responsible for botulism. This bacterium produces spores that resemble a tennis racket shape. Botulism is a type of food poisoning caused by the ingestion of the toxin produced by Clostridium botulinum. Summary: B: Salmonellosis is caused by Salmonella bacteria, which do not exhibit a tennis racket appearance. C: Cholera is caused by Vibrio cholerae, which also does not resemble a tennis racket under the microscope. D: Dysentery is typically caused by bacteria such as Shigella or Entamoeba histolytica, neither of which exhibit the characteristic tennis racket appearance.