Urinalysis of a patient with acute cystitis shows leukocytes and a large number of gram-negative bacilli. Inoculation has resulted in the growth of mucous colonies that produce a green soluble pigment. What microorganism is the most likely cause of the patient's disorder?

Correct Answer: C

Rationale: The correct answer is C: Escherichia coli. E. coli is the most common cause of acute cystitis. It typically presents with leukocytes and gram-negative bacilli in the urine. The green pigment production indicates pyocyanin, which is a characteristic of E. coli. Pseudomonas aeruginosa (A) can also produce green pigment, but it is less common in urinary tract infections. Proteus mirabilis (B) is associated with a swarming motility pattern on agar, not mucous colonies. Klebsiella pneumoniae (D) is associated with pneumonia and other respiratory infections, not cystitis.

Correct Answer: A

Rationale: The correct answer is A: Hemolytic streptococci. Hemolytic streptococci are pathogenic bacteria that can cause severe infections in humans, indicating direct epidemiological danger. Hemolytic streptococci are commonly found in the respiratory tract and can be transmitted through the air, making them a good indicator of pathogenic microorganisms in the air. Summary: - B: Sarcina, molds, yeast, and Micrococci are not typically indicators of direct epidemiological danger related to pathogenic microorganisms in the air. - Hemolytic streptococci, on the other hand, are pathogenic bacteria that can cause serious infections and are commonly transmitted through the air, making them a suitable indicator in this context.

Correct Answer: A

Rationale: The correct answer is A: ocular lens. The ocular lens is the lens closest to the eye in a compound light microscope. This lens is responsible for magnifying the image produced by the objective lens. It typically has a magnification power of 10x. The objective lens, choice B, is positioned closer to the specimen and provides the primary magnification of the image. The condenser, choice C, is located beneath the stage and helps focus light onto the specimen. The stage, choice D, is where the specimen is placed for observation. Therefore, the ocular lens is the correct choice as it is the lens closest to the eye and responsible for further magnifying the image.

Correct Answer: C

Rationale: The correct answer is C: Staphylococcus saprophyticus. The rationale is that Staphylococcus saprophyticus is the only one among the listed species that is known to be resistant to novobiocin. This resistance is due to the specific mechanism of action of novobiocin, which targets DNA gyrase, and Staphylococcus saprophyticus possesses an altered DNA gyrase enzyme that renders it resistant to the antibiotic. Staphylococcus aureus and Staphylococcus epidermidis are susceptible to novobiocin, making choices A and B incorrect. Choice D, "none of the listed," is also incorrect as Staphylococcus saprophyticus is indeed resistant to novobiocin.

Correct Answer: A

Rationale: Step-by-step rationale for why the correct answer is A (Cholera): 1. Gram-negative curved mobile monotrichous bacilli: Vibrio cholerae, the causative agent of cholera, fits this description. 2. Do not produce spores or capsules: Vibrio cholerae does not produce spores or capsules. 3. Require alkaline reaction (pH 8.5-9.5): Vibrio cholerae thrives in alkaline environments. 4. Enteric infection: Cholera is a classic example of an enteric infection transmitted through contaminated food or water. Summary of why other choices are incorrect: B: Shigellosis is caused by Shigella species, which are gram-negative, but they are not curved bacilli and do not require an alkaline pH. C: Typhoid fever is caused by Salmonella Typhi, which are gram-negative but are not curved bacilli and do not require an alkaline pH.