Nokea
Carious cavities of a 29-year-old patient contain the parasitic protozoa. It is established that they relate to the Sarcodina class. Specify these single-celled organisms:
- A. Entamoeba gingivalis
- B. Entamoeba histolutica
- C. Entamoeba coli
- D. Amoeba proteus
Correct Answer: A
Rationale: The correct answer is A: Entamoeba gingivalis. Firstly, it is important to note that Entamoeba gingivalis is commonly found in the oral cavity, specifically in carious cavities. Secondly, Entamoeba gingivalis belongs to the Sarcodina class, which is characterized by their amoeboid movement using pseudopods. This protozoa is associated with oral health issues, particularly in individuals with poor oral hygiene.
Now, let's analyze why the other choices are incorrect:
B: Entamoeba histolutica is known for causing amoebic dysentery, not commonly associated with oral cavities.
C: Entamoeba coli is typically found in the human large intestine, not in oral cavities.
D: Amoeba proteus is a free-living amoeba commonly used in laboratory studies and not typically associated with oral cavity infections.
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At a bacteriological laboratory animal skins are analyzed by means of Ascoli precipitaion test. What is detected if the reaction is positive?
- A. Anthrax agent antigens
- B. Brucellosis agent
- C. Anaerobic infection toxin
- D. Plague agent
Correct Answer: A
Rationale: The Ascoli precipitation test is specifically used to detect anthrax agent antigens. The test involves mixing a patient's serum with a solution containing anthrax antigens, leading to precipitation if the antigens are present. Therefore, a positive reaction in this test indicates the presence of anthrax agent antigens. The other choices (B: Brucellosis agent, C: Anaerobic infection toxin, D: Plague agent) are incorrect because the Ascoli precipitation test is not designed to detect these specific agents or toxins.
A patient with fever, enlarged lymph nodes, and bacteremia was diagnosed with plague. The Gram-stained smear revealed bipolar-staining, Gram-negative rods. What is the causative agent?
- A. Yersinia pestis
- B. Francisella tularensis
- C. Brucella abortus
- D. Clostridium botulinum
Correct Answer: A
Rationale: The correct answer is A: Yersinia pestis. Y. pestis is the causative agent of plague, characterized by fever, enlarged lymph nodes, and bacteremia. The bipolar-staining, Gram-negative rods seen on Gram stain are typical of Y. pestis.
Incorrect choices:
B: Francisella tularensis causes tularemia, not plague.
C: Brucella abortus causes brucellosis, not plague.
D: Clostridium botulinum causes botulism, not plague.
In summary, the key features of the patient's presentation and the Gram stain findings align with Yersinia pestis as the correct causative agent of plague.
Bacteria that have a single polar flagellum at one end are referred to as:
- A. monotrichous
- B. monotrichous
- C. amphitrichous
- D. peritrichous
Correct Answer: B
Rationale: Step-by-step rationale:
1. Monotrichous means having a single flagellum at one end.
2. The term "polar" indicates that the flagellum is located at one end of the bacterium.
3. Therefore, bacteria with a single polar flagellum are referred to as monotrichous.
4. Choice A is a typo, as it is the same as the correct answer B.
Summary:
- Choice A is a typo, as it duplicates the correct answer.
- Choice C, amphitrichous, refers to bacteria with a flagellum at each end.
- Choice D, peritrichous, describes bacteria with flagella distributed over the entire surface.
Gram-negative, capsulated bacteria with capsule, lactose-positive colonies. Isolated for the first time in pneumonia, but have more important role in urinary infections, otitis, meningitides, sepsis, nosocomial infections:
- A. Staphylococcus aureus
- B. Klebsiella pneumonia
- C. Streptococcus pneumoniae
- D. Mycobacterium tuberculosis
Correct Answer: B
Rationale: The correct answer is B: Klebsiella pneumoniae. This bacterium is gram-negative, capsulated, and forms lactose-positive colonies. It was first isolated in pneumonia but is more commonly associated with urinary infections, otitis, meningitides, sepsis, and nosocomial infections. Klebsiella pneumoniae fits all the characteristics mentioned in the question, making it the correct choice.
Incorrect choices:
A: Staphylococcus aureus is gram-positive and does not have a capsule.
C: Streptococcus pneumoniae is also gram-positive and does not fit the description given.
D: Mycobacterium tuberculosis is an acid-fast bacterium associated with tuberculosis, but it is neither gram-negative nor lactose-positive.
A 32-year-old patient undergoing dental examination was found to have some rash-like lesions resembling secondary syphilis in the oral cavity. The patient was referred for the serological study with the purpose of diagnosis confirmation. In order to detect antibodies in the serum, living Treponema were used as diagnosticum. What serological test was performed?
- A. Immobilization
- B. Passive hemagglutination
- C. Precipitation
- D. Complement binding
Correct Answer: B
Rationale: The correct answer is B: Passive hemagglutination. In this test, red blood cells coated with Treponema antigens agglutinate in the presence of patient's serum antibodies. This indicates the presence of antibodies against Treponema, confirming the diagnosis.
A: Immobilization test uses live Treponema to detect specific antibodies, but it is not commonly used for syphilis diagnosis.
C: Precipitation test is not commonly used for syphilis diagnosis.
D: Complement binding test is not specific for syphilis and is used more for autoimmune diseases.
Therefore, passive hemagglutination is the most appropriate serological test in this case due to its specificity and relevance to the presentation of the patient.