microbiology an introduction tortora test bank

Correct Answer: A

Rationale: The correct answer is A: Vibrio cholerae. This is because Vibrio cholerae is a Gram-negative, comma-shaped bacterium known to cause cholera. The characteristic shape and the association with cholera make it the most likely causative agent in this case. Explanation for incorrect choices: B: Shigella dysenteriae - Shigella dysenteriae is a Gram-negative bacterium that causes bacillary dysentery, not cholera. C: Salmonella typhi - Salmonella typhi is a Gram-negative bacterium that causes typhoid fever, not cholera. D: Campylobacter jejuni - Campylobacter jejuni is a Gram-negative bacterium that commonly causes foodborne gastroenteritis, not cholera.

Correct Answer: B

Rationale: The correct answer is B: Mefloquine. Mefloquine is a histoschizontocidal antimalarial drug commonly prescribed for prevention of malaria in travelers. It is effective against the liver stage of the malaria parasite, which is crucial for preventing the development of the disease. Chingamin (A) is not a commonly used antimalarial drug. Biseptol (C) is a combination antibiotic and is not effective against malaria parasites. Quinine (D) is primarily used for treating malaria, not preventing it, and it is not specifically histoschizontocidal.

Correct Answer: A

Rationale: The correct answer is A: BCG (Bacille Calmette-Guerin). BCG is the vaccine used for tuberculosis prevention, not only for newborns but also for older children and adults. BCG helps in protecting against severe forms of tuberculosis in infants. Diphteria and tetanus toxoids and pertussis vaccine (choice B) is for protection against diphtheria, tetanus, and pertussis, not tuberculosis. Diphtheria and tetanus anatoxin vaccine (choice C) provides protection against diphtheria and tetanus, not tuberculosis. Adsorbed diphtheria vaccine (choice D) is specifically for diphtheria, not tuberculosis. Therefore, the correct choice is A as it is the only vaccine related to tuberculosis prevention.

Correct Answer: A

Rationale: The correct answer is A: viruses. Viruses are always in a parasitic form of interaction with the individual because they cannot survive or reproduce outside of a host cell. They rely on host cells to replicate and cause harm. Non-pathogenic bacteria (choice B) do not always cause harm and can coexist with the individual. Facultative pathogenic bacteria (choice C) can switch between being beneficial and harmful. Therefore, the correct answer is A as viruses always rely on a host for survival and reproduction.

Correct Answer: A

Rationale: The correct answer is A: Vibrio cholerae. This is because Vibrio cholerae is a Gram-negative, comma-shaped bacterium known to cause cholera. The characteristic shape and the association with cholera make it the most likely causative agent in this case. Explanation for incorrect choices: B: Shigella dysenteriae - Shigella dysenteriae is a Gram-negative bacterium that causes bacillary dysentery, not cholera. C: Salmonella typhi - Salmonella typhi is a Gram-negative bacterium that causes typhoid fever, not cholera. D: Campylobacter jejuni - Campylobacter jejuni is a Gram-negative bacterium that commonly causes foodborne gastroenteritis, not cholera.