Nokea
Which type of bacteria can survive in both aerobic and anaerobic environments?
- A. Obligate aerobes
- B. Facultative anaerobes
- C. Obligate anaerobes
- D. Microaerophiles
Correct Answer: B
Rationale: Certainly! The correct answer is B: Facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic environments due to their ability to switch between utilizing oxygen for respiration in aerobic conditions and utilizing fermentation or anaerobic respiration in anaerobic conditions. This flexibility allows them to thrive in diverse environments.
Explanation for incorrect choices:
A: Obligate aerobes require oxygen for respiration and cannot survive in anaerobic environments.
C: Obligate anaerobes can only survive in the absence of oxygen and would not thrive in aerobic conditions.
D: Microaerophiles require low levels of oxygen to grow and are not as versatile in adapting to varying oxygen levels compared to facultative anaerobes.
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Microscopy of sputum revealed acid-fast bacilli stained red against a blue background using Ziehl-Neelsen staining. What disease does this finding suggest?
- A. Tuberculosis
- B. Diphtheria
- C. Pneumonia
- D. Leprosy
Correct Answer: A
Rationale: The presence of acid-fast bacilli stained red against a blue background indicates mycobacteria, specifically Mycobacterium tuberculosis in this case. Ziehl-Neelsen staining is commonly used to detect tuberculosis. Diphtheria is caused by Corynebacterium diphtheriae, which does not stain with Ziehl-Neelsen. Pneumonia is a general term for lung infections caused by various pathogens. Leprosy is caused by Mycobacterium leprae, which requires special staining methods different from Ziehl-Neelsen.
The normal microflora is related to the defense in pathogens in
- A. circulatory system
- B. hepatobiliary tract
- C. skin and mucus
- D. CNS
Correct Answer: C
Rationale: The normal microflora plays a crucial role in defending against pathogens in the skin and mucus. This is because the skin and mucus act as physical barriers and the normal microflora outcompetes potential pathogens, preventing their colonization. In contrast, the circulatory system (A), hepatobiliary tract (B), and CNS (D) are not typically colonized by normal microflora, so they do not directly contribute to defense against pathogens in those areas.
Infections of Legionella pneumophila are treated with:
- A. Penicillins and cephalosporins
- B. Ethambutol and isoniazid
- C. Macrolides or fluoroquinolones
- D. Second and third generation cephalosporins
Correct Answer: C
Rationale: The correct answer is C: Macrolides or fluoroquinolones. Legionella pneumophila is a bacterium that causes Legionnaires' disease, a severe form of pneumonia. Macrolides (like azithromycin) and fluoroquinolones (like levofloxacin) are the recommended first-line treatments due to their ability to penetrate into lung tissues where Legionella infects. Penicillins and cephalosporins (choice A) are not effective against Legionella as it is intracellular and resistant to these antibiotics. Ethambutol and isoniazid (choice B) are used to treat tuberculosis, not Legionella infections. Second and third generation cephalosporins (choice D) are also not effective against Legionella. Therefore, the best choice for treating Legionella pneumophila infections is macrolides or fluoroquinolones.
4 days after a patient received a gunshot wound of the middle third of the thigh soft tissues his condition suddenly began deteriorating. There are complaints of bursting pain in the wound; pain increases during the last 12 hours. Edema of skin and hypodermic tissue quickly grows. Body temperature is 38,2oC, heart rate is 102/min. The wound edges gape, are dull in color; the muscles, viable as of day before, now protrude into the wound, look boiled, are dull in color, have dirty-grey coating and fall apart when being held with forceps. What infection has developed in the wound?
- A. Anaerobic
- B. Aerobic gram-negative
- C. Putrid
- D. Aerobic gram-positive
Correct Answer: A
Rationale: The correct answer is A: Anaerobic infection. The sudden deterioration, bursting pain, edema, foul appearance of wound, and presence of gas are indicative of gas gangrene caused by anaerobic bacteria like Clostridium perfringens. These bacteria thrive in low oxygen environments, such as deep wound tissues. The symptoms align with the classic presentation of gas gangrene, necessitating immediate surgical intervention.
Choice B: Aerobic gram-negative, is incorrect because anaerobic bacteria, not aerobic gram-negative bacteria, are responsible for gas gangrene.
Choice C: Putrid, is incorrect as it is a general term referring to foul-smelling decay and does not specify the type of infection.
Choice D: Aerobic gram-positive, is incorrect as gas gangrene is typically caused by anaerobic bacteria, not aerobic gram-positive bacteria.
The term “infectious process†means “all biological processes carried out after…â€
- A. The attachment and penetration of microbes into the microorganism
- B. The attachment and penetration of microbes into the microorganisms regardless of whether or not there is clinical manifestation
- C. The penetration of microbes into the macroorganism and always manifest clinically
- D. No correct answer
Correct Answer: B
Rationale: The correct answer is B because the term "infectious process" refers to all biological processes that occur after the attachment and penetration of microbes into the host organism, regardless of whether there are clinical manifestations. This includes the colonization, multiplication, and spread of the microorganisms within the host.
Explanation:
A: Incorrect because it only mentions the attachment and penetration of microbes into the microorganism, missing the subsequent processes.
C: Incorrect because it is too specific, stating that the penetration of microbes always manifests clinically, which is not always the case.
D: Incorrect because there is a correct answer, which is B, as explained above.