A saucer-shaped liquefaction in a gelatin stab is referred to as:

Correct Answer: C

Rationale: The correct answer is C: crateriform. In a gelatin stab, a saucer-shaped liquefaction indicates a depression or crater-like shape. This term accurately describes the appearance of the liquefaction. A: napiform means turnip-shaped, which is not relevant to the shape in a gelatin stab. B: saccate means pouch-like, which does not match the saucer-shaped description. D: stratiform refers to something in layers, which is not applicable to the shape of the liquefaction. Therefore, C is the most appropriate term to describe the saucer-shaped liquefaction in a gelatin stab.

Correct Answer: B

Rationale: The correct answer is B: Fluconazole. Rationale: 1. Candidiasis is a fungal infection, so an antimycotic agent is needed. 2. β-lactam antibiotics like ampicillin can lead to fungal overgrowth, necessitating an antimycotic. 3. Fluconazole is an antifungal agent effective against Candida species. 4. Streptomycin is an antibiotic, not an antifungal. 5. Phthalylsulfathiazole is an antibacterial sulfonamide, not an antifungal. 6. Ampicillin is an antibiotic, not an antifungal.

Correct Answer: D

Rationale: The correct answer is D: Index of fecal coli-forms. Fecal coli-forms are bacteria found in the intestines of warm-blooded animals, including humans. Their presence in water indicates fecal contamination, which is a common source of hepatitis A transmission. Monitoring the index of fecal coli-forms can help identify potential sources of contamination and assess the risk of disease transmission. A: Number of coli-phages - Coli-phages are viruses that infect coliform bacteria and are not directly related to fecal contamination. B: Escherichia coli index - While E. coli is a type of coliform bacteria found in the intestines of warm-blooded animals, it alone may not be a reliable indicator of fecal contamination in water sources. C: Oxidability - Oxidability is a measure of the water's ability to react with oxygen and does not provide direct information about fecal contamination or the presence of pathogens like hepatitis A. In summary,

Correct Answer: B

Rationale: The correct answer is Staphylococcus saprophyticus (choice B). This bacterium is a common cause of urinary tract infections in young women. It typically grows on blood agar without hemolysis and appears as Gram-positive cocci under the microscope. Proteus mirabilis (choice A) is known for urease production, causing alkaline urine. Staphylococcus aureus (choice C) is a common cause of skin and soft tissue infections, not urinary tract infections. Pseudomonas aeruginosa (choice D) is an opportunistic pathogen often seen in nosocomial infections, not typically associated with urinary tract infections in healthy individuals.

Correct Answer: D

Rationale: The correct answer is D: Pulmonary tuberculosis. The presence of red bacilli stained with Ziehl-Nielsen method indicates acid-fast bacteria, which are characteristic of Mycobacterium tuberculosis, the causative agent of tuberculosis. The size and appearance of the bacilli described match those of M. tuberculosis. Chronic pneumonia, along with the specific staining pattern, strongly suggests tuberculosis as the likely diagnosis. Explanation for other choices: A: Pneumococcal pneumonia is caused by Streptococcus pneumoniae, which would not show red bacilli on Ziehl-Nielsen staining. B: Pulmonary actinomycosis is caused by Actinomyces species, not acid-fast bacteria like M. tuberculosis. C: Pulmonary candidiasis is caused by Candida species, which are fungi and do not appear as red bacilli on staining.

Correct Answer: A

Rationale: The correct answer is A: Entamoeba histolytica. This protozoon is known to cause amoebic dysentery, presenting symptoms of weakness, intestinal pain, and indigestion. The presence of microbial cysts with four nuclei in fecal samples is characteristic of Entamoeba histolytica. These cysts are the infective form of the parasite and can cause severe invasive disease in the intestines. Incorrect choices: B: Entamoeba coli does not typically cause invasive disease or severe symptoms like those described in the question. C: Balantidium is a ciliated protozoan that causes balantidiasis, which presents differently from the symptoms described in the question. D: Trichomonad is a flagellated protozoan that typically infects the urogenital tract, not the intestine, and does not form cysts with four nuclei. In summary, the key clues in the question were the symptoms of weakness, intestinal pain,

Correct Answer: A

Rationale: The correct answer is A: Centers for Disease Control and Prevention. The CDC is a U.S. government agency responsible for protecting public health and safety. The correct answer is the only choice that accurately reflects the agency's purpose. Choice B (Children's Disease Center) is incorrect because the CDC's scope is not limited to children's health. Choice C (Central Disaster Control Center) is incorrect as the CDC primarily focuses on disease prevention. Choice D (Central Drug Evaluation and Control Center) is incorrect as the CDC's main focus is not on drug evaluation. Thus, the correct answer is A as it aligns with the CDC's mission and responsibilities.

Correct Answer: A

Rationale: The correct answer is A: Trichomonas vaginalis. Trichomonas vaginalis is a sexually transmitted protozoan that causes trichomoniasis. The pear-shaped flagellated protozoa with an undulating membrane described in the question match the morphology of Trichomonas vaginalis. It is typically found in vaginal discharge of infected individuals. Giardia lamblia (B) is a different protozoan that causes giardiasis and has a distinct morphology of a teardrop shape with flagella. Trypanosoma brucei (C) causes African sleeping sickness and Leishmania donovani (D) causes visceral leishmaniasis, both of which have different morphologies and clinical presentations compared to Trichomonas vaginalis.

Correct Answer: D

Rationale: The correct answer is D because all of these symptoms are early signs of rabies. A short period of depression, nausea, and restlessness are common initial symptoms of rabies infection. These symptoms may be followed by more severe manifestations, such as aggression, confusion, and difficulty swallowing. Therefore, option D is the correct choice as it encompasses all the early symptoms of rabies. Options A, B, and C are incorrect as they focus on individual symptoms, whereas rabies typically presents with a combination of these early signs.