Nokea
Study of bacteriological sputum specimens stained by the Ziel-Neelsen method revealed some bright-red acid-resistant bacilli that were found in groups or singularly. When inoculated onto the nutrient media, the signs of their growth show up on the 10-15 day. These bacteria relate to the following family:
- A. Micobacterium tuberculosis
- B. Yersinia pseudotuberculosis
- C. Histoplasma dubrosii
- D. Klebsiella rhinoscleromatis
Correct Answer: A
Rationale: The correct answer is A: Mycobacterium tuberculosis.
1. Bright-red acid-resistant bacilli indicate the presence of mycolic acids in the cell wall, characteristic of Mycobacterium species.
2. Found in groups or singularly suggests the clumping nature of acid-fast bacilli.
3. Growth appearing after 10-15 days on nutrient media is consistent with the slow growth rate of Mycobacterium tuberculosis.
4. Yersinia pseudotuberculosis (B) and Klebsiella rhinoscleromatis (D) are not acid-fast bacilli and do not match the growth characteristics described.
5. Histoplasma dubrosii (C) is a fungus, not a bacterium, and does not exhibit acid-fast staining or the described growth pattern.
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A patient with severe abdominal pain and diarrhea had a stool sample cultured. The bacteria were Gram-negative rods that did not ferment lactose. What is the most likely causative agent?
- A. Salmonella enterica
- B. Shigella dysenteriae
- C. Escherichia coli
- D. Proteus vulgaris
Correct Answer: A
Rationale: The correct answer is A: Salmonella enterica. This is because Salmonella are Gram-negative rods that do not ferment lactose, which fits the description in the question. Additionally, Salmonella is a common cause of severe abdominal pain and diarrhea. Shigella dysenteriae is a Gram-negative rod that also causes severe diarrhea but it does not share the characteristic of not fermenting lactose. Escherichia coli is a Gram-negative rod that does ferment lactose. Proteus vulgaris is also a Gram-negative rod but it is not commonly associated with severe abdominal pain and diarrhea, making it an unlikely causative agent in this scenario.
The effect of which of the following toxins DOES NOT MANIFEST with neurological symptoms:
- A. Tetanospasmin
- B. Diphtheria exotoxin
- C. Botulinum exotoxin
- D. Pertussis exotoxin
Correct Answer: D
Rationale: Certainly! The correct answer is D: Pertussis exotoxin. Pertussis toxin primarily affects the respiratory system causing whooping cough. It does not directly target the nervous system like the other toxins listed. Tetanospasmin causes muscle spasms, Diphtheria exotoxin affects the heart and nerves, and Botulinum exotoxin causes paralysis by blocking neurotransmitter release. Therefore, Pertussis exotoxin is the only toxin among the options that does not manifest with neurological symptoms.
Bacterial infections of the female reproductive system include:
- A. vaginitis, toxic shock syndrome, endometritis, and salpingitis
- B. nephritis, endometritis, vaginitis, and pelvic inflammatory disease
- C. toxic shock syndrome, nephritis, endometritis, and cystitis
- D. endometritis, vaginitis, cystitis, and toxic shock syndrome
Correct Answer: A
Rationale: Rationale:
1. Vaginitis is a common bacterial infection in the female reproductive system.
2. Toxic shock syndrome can be caused by certain bacterial infections.
3. Endometritis is inflammation of the endometrium often due to bacterial infections.
4. Salpingitis is inflammation of the fallopian tubes, commonly caused by bacteria.
Summary:
- Choice B: Nephritis is a kidney infection, not related to female reproductive system infections.
- Choice C: Nephritis and cystitis are not specific to the female reproductive system.
- Choice D: Cystitis is a bladder infection, not typically considered part of female reproductive system infections.
The specific prevention (by vaccination) of the disease gas gangrene (caused by Clostridium perfringens) is based on:
- A. Killed whole cell vaccine
- B. Anatoxin
- C. There is no specific prevention by vaccination
- D. Alive attenuated vaccine
Correct Answer: B
Rationale: The correct answer is B: Anatoxin. An anatoxin is a toxin that has been rendered harmless while retaining its ability to stimulate an immune response. Gas gangrene is caused by the toxins produced by Clostridium perfringens, not the bacteria itself. Therefore, vaccination with an anatoxin can trigger the immune system to produce antibodies against the toxin, providing immunity against the disease.
A: Killed whole cell vaccine - Gas gangrene is caused by toxins, not the whole bacterium. This type of vaccine may not be effective in preventing the disease.
C: There is no specific prevention by vaccination - This is incorrect, as vaccination with an anatoxin can prevent gas gangrene.
D: Alive attenuated vaccine - Attenuated vaccines contain live, weakened forms of the pathogen. However, for gas gangrene prevention, targeting the specific toxin with an anatoxin vaccine is more appropriate.
How do people get infected with diphtheria
- A. by swimming in contaminated water
- B. by transmission
- C. by droplets and physical contact
- D. by contaminated food
Correct Answer: C
Rationale: The correct answer is C because diphtheria is primarily spread through respiratory droplets and physical contact with an infected person. The bacteria responsible for diphtheria is transmitted through coughing, sneezing, or sharing personal items. Swimming in contaminated water (A) does not spread diphtheria. Transmission (B) is a broad term and does not specifically address the mode of transmission for diphtheria. Contaminated food (D) is not a typical route of diphtheria transmission. Therefore, option C is the most accurate choice based on the known mode of transmission for diphtheria.