Which bacteria are capable of forming spores to survive extreme conditions?

Correct Answer: C

Rationale: Rationale: 1. Both Clostridium botulinum and Bacillus anthracis are known to form spores. 2. Spore formation is a mechanism for survival in harsh conditions. 3. Both bacteria are capable of causing severe diseases in humans. Summary: - Choice A and B are incorrect because each bacteria listed is capable of spore formation. - Choice D is incorrect as both bacteria mentioned can form spores to survive extreme conditions.

Correct Answer: A

Rationale: The correct answer is A: Toxin production test. Rationale: 1. Diphtheria is caused by a toxin produced by Corynebacterium diphtheriae. 2. To confirm if the carrier is dangerous, we need to test if they are producing the toxin. 3. The toxin production test directly assesses if the bacteria are producing the harmful toxin. 4. Positive results indicate the carrier is dangerous and can transmit the disease to others. Summary of other choices: B: Mouse neutralization test - Used to detect diphtheria antitoxin levels in blood, not to confirm if the carrier is dangerous. C: Immunofluorescence test - Used to detect specific antigens or antibodies, not directly related to confirming the carrier's danger. D: Complement fixation test - Measures immune response, not specific to toxin production confirmation.

Correct Answer: A

Rationale: The correct answer is A: Nystatin. Nystatin is an antifungal medication, not an antibiotic used to treat bacterial infections like generalized meningococcal infection. Penicillin G, macrolides, and chloramphenicol are antibiotics commonly used to treat bacterial infections, including meningococcal infections. Penicillin G is the drug of choice for meningococcal infections, while macrolides and chloramphenicol are alternative options. Nystatin is not effective against bacteria, so it is not a suitable treatment for meningococcal infections.

Correct Answer: D

Rationale: The correct answer is D (15-Oct) because boiling items for at least 15 minutes is necessary to effectively kill most vegetative bacteria and viruses. This duration ensures that the water reaches a high enough temperature to destroy harmful microorganisms. Choices A, B, and C are incorrect because they do not provide a sufficient amount of time for the water to reach the necessary temperature to effectively kill bacteria and viruses. Shorter durations may not be effective in ensuring food safety.

Correct Answer: C

Rationale: The correct answer is C: rotaviruses. Rotaviruses are the most common cause of infectious diarrhea in infants and children due to their highly contagious nature and ability to spread easily in childcare settings. They are known to cause severe diarrhea, vomiting, and dehydration in young children. Noroviruses (A), adenoviruses (B), and caliciviruses (D) can also cause diarrhea, but rotaviruses are specifically known for their prevalence and severity in the pediatric population. This is why C is the correct answer.

Correct Answer: B

Rationale: The correct answer is B because antigenic drift is not caused by the exchange of genetic information between animal and human influenza viruses. Antigenic drift is actually due to point mutations in the genes that encode for the surface proteins of the virus, leading to small changes in the antigens. These mutations can affect the hemagglutinin of both type A and B influenza viruses, making choices A and C correct. Choice D is incorrect because antigenic drift can occur in both type A and B influenza viruses, with type B being less prone to drift compared to type A.

Correct Answer: D

Rationale: The correct answer is D: Parenteral introduction of antitetanus serum. The symptoms described in the question, such as bilateral ptosis, mydriatic pupils, and difficulty reading, are indicative of tetanus infection. The source of infection could be the scratch on the knee, which allowed the tetanus bacteria to enter the body. The most appropriate therapy for tetanus is the administration of antitetanus serum to neutralize the tetanus toxin. Antibotulinic serum (choice A) is not appropriate as it is used for botulism, which presents differently. Disintoxication (choice B) is too general and does not address the specific cause of the symptoms. Antibiotics (choice C) are not effective in treating tetanus because it is caused by a toxin, not a bacterial infection. Therefore, the correct course of action is to administer antitetanus serum to the patient.

Correct Answer: D

Rationale: The correct answer is D: Binary fission. Binary fission is a method of bacterial cell division, not a method of acquiring genetic material. Transformation, conjugation, and transduction are mechanisms through which bacteria can acquire genetic material from other sources. Transformation involves the uptake of naked DNA from the environment, conjugation is the transfer of genetic material through direct cell-to-cell contact, and transduction is the transfer of genetic material via bacteriophages. Therefore, binary fission is the only option that does not involve the acquisition of new genetic material.

Correct Answer: B

Rationale: The correct answer is B: kidneys. The kidneys are the primary organs responsible for excreting drugs from the body through urine. They filter the blood and remove waste products, including drugs, through the process of urine formation. The lungs primarily excrete gases and volatile substances, not drugs. The small intestines are mainly involved in absorption of nutrients, not drug excretion. The spleen is part of the immune system and does not play a direct role in drug excretion.