microbiology basic and clinical principles test bank

Correct Answer: A

Rationale: The correct answer is A: Robert Hooke. Hooke published Micrographia in 1665, showcasing detailed illustrations of insects, sponges, and plant cells under the microscope. Hooke's work was groundbreaking in advancing the field of microscopy. Van Leeuwenhoek is known for discovering microorganisms but did not publish Micrographia. Janssen and Needham were not associated with Micrographia. Therefore, A is the correct answer.

Correct Answer: C

Rationale: The correct answer is C: Increased active efflux from the bacterial cell. This is the most important mechanism of tetracycline resistance because it involves the bacteria actively pumping out the antibiotic, reducing its intracellular concentration. This prevents tetracycline from effectively targeting bacterial ribosomes. Choice A is incorrect as tetracycline resistance typically involves active efflux rather than reduced influx. Choice B is incorrect because tetracycline resistance mechanisms do not primarily involve altered cell membrane components affecting passive influx. Choice D is also incorrect as tetracycline resistance mechanisms do not typically involve direct enzymatic inactivation of the antibiotic.

Correct Answer: A

Rationale: The correct answer is A: Tetanus. The symptoms of tonic tension of the masticatory muscles following a dog bite are indicative of tetanus, caused by the bacterium Clostridium tetani. The incubation period of tetanus is usually 3-21 days, consistent with the patient's history of being bitten 12 days ago. Tetanus toxin causes muscle stiffness and spasms, leading to the inability to open the mouth. Rabies (B) presents with hydrophobia and neurological symptoms. Hysteria (C) is a psychological condition. Trigeminal neuralgia (D) is characterized by severe facial pain, not muscle stiffness.

Correct Answer: A

Rationale: The correct answer is A: BCG. BCG vaccine is commonly used for tuberculosis prevention because it provides immunity against Mycobacterium tuberculosis. Mantoux is a test, not a vaccine. DTaP vaccine is for diphtheria, tetanus, and pertussis, not tuberculosis. Anatoxin is a type of toxoid vaccine, not used for tuberculosis prevention. BCG vaccine has been shown to be effective in preventing severe forms of tuberculosis in infants, making it the appropriate choice in this scenario.

Correct Answer: B

Rationale: The correct answer is B: Malarial plasmodiums. The description of crescent bodies with a pointed end, blue cytoplasm, and red nucleus corresponds to the characteristics of Plasmodium species seen in Romanovsky's stain. Plasmodium species are known to cause malaria and have distinct features like the ones described. Incorrect choices: A: Toxoplasmas - Toxoplasma gondii typically appear as tachyzoites or bradyzoites under staining, not crescent bodies. C: Dermotropic leishmania - Leishmania species appear as amastigotes in tissue smears, not crescent bodies. D: Viscerotropic leishmania - Similar to choice C, Leishmania species do not typically present as crescent bodies in stained specimens.