Nokea
Which bacteria is responsible for causing the disease known as cholera?
- A. Clostridium botulinum
- B. Vibrio cholerae
- C. Salmonella enterica
- D. Escherichia coli
Correct Answer: B
Rationale: The correct answer is B: Vibrio cholerae. Cholera is caused by Vibrio cholerae, a bacterium that produces a toxin leading to severe diarrhea and dehydration. Clostridium botulinum (A) causes botulism, Salmonella enterica (C) causes salmonellosis, and Escherichia coli (D) can cause various illnesses but not cholera. Vibrio cholerae is the only bacteria specifically known for causing cholera.
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A 25-year-old patient was delivered to an infectious diseases unit on the 3rd day of illness with complaints of headache, pain in lumbar spine and gastrocnemius muscles, high fever, chill. Objectively: condition of moderate severity. Scleras are icteric. Pharynx is hyperemic. Tongue is dry with dry brown coating. Abdomen is distended. Liver is enlarged by 2 cm. Spleen is not enlarged. Palpation of muscles, especially gastrocnemius muscles, is painful. Urine is dark in color. Stool is normal in color. The most likely diagnosis is:
- A. Leptospirosis
- B. Infectious mononucleosis
- C. Malaria
- D. Viral hepatitis A
Correct Answer: A
Rationale: The correct diagnosis is Leptospirosis. Leptospirosis presents with headache, fever, muscle pain, jaundice, and kidney involvement. The patient's symptoms of headache, lumbar and muscle pain, high fever, icteric scleras, and dark urine are classic for Leptospirosis. The enlarged liver could be due to liver involvement in the disease. The absence of splenic enlargement and normal stool color rule out malaria. Infectious mononucleosis typically presents with sore throat and lymphadenopathy, which are absent in this case. Viral hepatitis A may present with similar symptoms, but the presence of muscle pain and dark urine is more indicative of Leptospirosis. Therefore, based on the patient's symptoms and clinical findings, Leptospirosis is the most likely diagnosis.
The cytoplasmic membrane in bacteria is composed of:
- A. Phospholipids, glycerol and glycolipids
- B. Lipopolysaccharides
- C. Lipopolysaccharides and peptidoglycan
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A because the cytoplasmic membrane in bacteria is primarily composed of phospholipids, glycerol, and glycolipids. Phospholipids form the basic structure of the membrane, with glycerol serving as the backbone and glycolipids present on the outer surface. Lipopolysaccharides (choice B) are primarily found in the outer membrane of Gram-negative bacteria, not the cytoplasmic membrane. Choice C is incorrect because peptidoglycan is a component of the bacterial cell wall, not the cytoplasmic membrane. Choice D is incorrect as the cytoplasmic membrane in bacteria is indeed composed of phospholipids, glycerol, and glycolipids.
Sterilization is a process that:
- A. Destroys most microorganism, but spores remain viable
- B. Leads to complete destruction of all microorganisms, including resistant forms such as spores
- C. Reduces the number of microorganisms on the surface of the skin
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B because sterilization is the process of completely destroying all microorganisms, including resistant forms like spores, ensuring no viable organisms remain. This is crucial for ensuring complete elimination of potential pathogens. Choice A is incorrect because sterilization should eliminate all microorganisms, including spores. Choice C is incorrect as it describes disinfection, not sterilization. Choice D is incorrect because sterilization aims to eradicate all microorganisms, not leave any viable ones behind.
Examination of the duodenal contents revealed some pear-shaped protozoa with two nuclei and four pairs of flagella. The organisms had also two axostyles between the nuclei and a ventral adhesive disc. What protozoan representative was found in the patient?
- A. Lamblia
- B. Toxoplasma
- C. Leishmania
- D. Intestinal trichomonad
Correct Answer: A
Rationale: Step 1: Pear-shaped protozoa with two nuclei, four pairs of flagella, two axostyles, and a ventral adhesive disc match the characteristics of Giardia lamblia.
Step 2: Giardia lamblia is commonly found in the duodenum and causes giardiasis.
Step 3: Lamblia is the correct answer as it specifically matches all the described characteristics.
Summary: B, Toxoplasma, is incorrect as it does not match the described features. C, Leishmania, does not have the specific characteristics mentioned. D, Intestinal trichomonad, does not match the detailed descriptions given.
Mycoplasma species lack:
- A. Cell wall
- B. Plasma membrane
- C. DNA
- D. Ribosomes
Correct Answer: A
Rationale: The correct answer is A: Cell wall. Mycoplasma species lack a cell wall, making them unique among bacteria. This is because they have a flexible cell membrane that provides structural support instead of a rigid cell wall. The absence of a cell wall allows them to be pleomorphic and gives them resistance to certain antibiotics targeting cell wall synthesis. Plasma membrane (B), DNA (C), and ribosomes (D) are present in Mycoplasma species, so they are not the correct answer.