microbiology chapter 1 test bank

Correct Answer: C

Rationale: The correct answer is C: Measles serological test. This is because the clinical presentation of high fever, maculopapular rash, and Filatov-Koplik's spots on the buccal mucosa are classic symptoms of measles. The presence of Filatov-Koplik's spots is highly specific for measles. Performing a measles serological test will help confirm the diagnosis by detecting measles-specific antibodies in the blood. Incorrect choices: A: Mumps serological test - Mumps typically presents with parotitis (swelling of the parotid glands) and not with Filatov-Koplik's spots. B: Enteroviruses serological test - Enteroviruses do not typically cause Filatov-Koplik's spots or the classic triad of symptoms seen in measles. D: Influenza virus serological test - Influenza virus does not cause Filatov-Koplik's spots and the characteristic rash seen

Correct Answer: D

Rationale: The correct answer is D because it encompasses the true statements regarding the laboratory diagnosis of urinary tract infections. A: Bacteriuria of less than 10^5 can be significant in treated patients due to the development of antibiotic resistance. B: Staphylococcus aureus, Salmonella typhi, and Mycobacterium tuberculosis may be significant regardless of quantity due to their pathogenic nature. C: Leukocyturia indicates inflammation, and even a lower number of leukocytes can be clinically significant. Therefore, option D covers all these aspects making it the correct choice.

Correct Answer: D

Rationale: The correct answer is D: Viscerotropic Leishmania. The presence of crescent-shaped bodies with pointed tips, blue cytoplasm, and red nuclei is characteristic of Leishmania species. Viscerotropic Leishmania causes visceral leishmaniasis, also known as kala-azar, which affects the internal organs. Toxoplasma typically presents as tachyzoites, not crescent-shaped bodies. Plasmodium malariae is a malaria parasite with different morphology. Dermatotropic Leishmania causes cutaneous leishmaniasis, not the visceral form indicated by the morphology described in the question.

Correct Answer: C

Rationale: The correct answer is C: ECHO virus infection. ECHO virus is transmitted via the fecal-oral route, meaning the virus is passed from feces to the mouth. This transmission occurs through contaminated food, water, or surfaces. Relapsed fever and spotted fever are generally transmitted by arthropod vectors like ticks. Pertussis, also known as whooping cough, spreads through respiratory droplets. Therefore, the fecal-oral route is not applicable to these diseases.

Correct Answer: A

Rationale: The correct answer is A: Clostridium tetani. The presence of Gram-positive rods with terminal spores resembling drumsticks indicates Clostridium tetani, the causative agent of tetanus. This bacterium forms spores at one end, giving it a drumstick appearance under the microscope. Clostridium perfringens (B) and Clostridium botulinum (D) do not have terminal spores. Bacillus anthracis (C) forms spores but typically appears as a square-ended or bamboo stick shape. Therefore, based on the microscopy findings, Clostridium tetani is the most likely microorganism responsible for the wound infection.