Nokea
Resident microflora is found in
- A. blood
- B. lung
- C. urethra
- D. cerebro-spinal fluid
Correct Answer: C
Rationale: The correct answer is C: urethra. Resident microflora refers to the normal, beneficial bacteria that inhabit a specific area of the body without causing harm. The urethra is one of the locations where resident microflora are commonly found. These bacteria play a vital role in maintaining a healthy balance and preventing harmful pathogens from colonizing the urethra. Blood (A), lung (B), and cerebro-spinal fluid (D) are not typical locations for resident microflora as these areas are usually sterile or have very limited microbial presence to prevent infections.
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Microscopic examination of pus sample taken from mandibular fistula canal and stained by Gram's method has revealed druses with gram-positive coloring in the center and cone-shaped structures with gram-negative coloring. Such morphology is characteristic of the agent of:
- A. Fusobacteriosis
- B. Actinomycosis
- C. Staphylococcal osteomyelitis
- D. Anaerobic infection
Correct Answer: B
Rationale: The correct answer is B: Actinomycosis. Actinomyces is a gram-positive bacterium that forms sulfur granules (druses) with gram-positive coloring in the center and filamentous structures resembling cones with gram-negative coloring. This morphology is characteristic of Actinomyces species. Fusobacteriosis (choice A) typically presents with gram-negative rods. Staphylococcal osteomyelitis (choice C) is caused by gram-positive staphylococci, not Actinomyces. Anaerobic infections (choice D) can be caused by various bacteria, but the specific morphology described in the question matches Actinomyces, making choice B the correct answer.
Which bacteria are capable of surviving in anoxic (oxygen-free) conditions?
- A. Obligate anaerobes
- B. Facultative anaerobes
- C. Obligate aerobes
- D. Microaerophiles
Correct Answer: A
Rationale: The correct answer is A: Obligate anaerobes. These bacteria can only survive in the absence of oxygen as they lack the enzymes needed for aerobic respiration. They typically use fermentation or anaerobic respiration for energy production.
Incorrect choices:
B: Facultative anaerobes can switch between aerobic and anaerobic metabolism based on oxygen availability.
C: Obligate aerobes require oxygen for survival and cannot survive in anoxic conditions.
D: Microaerophiles require low levels of oxygen for growth and are not capable of surviving in completely anoxic conditions.
A wound swab from a patient with severe tissue infection revealed Gram-positive rods in chains producing gas. The bacteria were spore-forming. What is the causative agent?
- A. Clostridium perfringens
- B. Bacillus anthracis
- C. Clostridium tetani
- D. Pseudomonas aeruginosa
Correct Answer: A
Rationale: The correct answer is A: Clostridium perfringens. This bacterium is a Gram-positive rod that forms chains and produces gas due to its ability to ferment carbohydrates. It is also spore-forming, which helps it survive harsh conditions. Clostridium perfringens is commonly associated with severe tissue infections and gas gangrene.
Choice B: Bacillus anthracis is also a spore-forming Gram-positive rod but is not typically associated with gas production or severe tissue infections.
Choice C: Clostridium tetani is a spore-forming bacterium that causes tetanus, not severe tissue infections with gas production.
Choice D: Pseudomonas aeruginosa is a Gram-negative bacterium and does not fit the description provided in the question.
During bacteriological examination of the purulent discharge obtained from a postoperative wound an inoculation on meat infusion agar has been performed. The inoculation has resulted in large colorless mucous colonies that in 24 hours with exposure to sunlight developed green-blue pigmentation and smell of honey or jasmine. Bacterioscopy revealed gram-negative lophotrichea. What bacterial culture is contained in purulent discharge?
- A. Pseudomonas aeruginosa
- B. Proteus vulgaris
- C. Klebsiella osaenae
- D. Streptomyces griseus
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is a gram-negative bacterium known for its green-blue pigmentation and sweet, fruity odor. The large colorless mucous colonies that develop green-blue pigmentation and honey or jasmine smell point towards Pseudomonas aeruginosa. The bacterioscopy revealing gram-negative lophotrichea further supports this identification. Proteus vulgaris and Klebsiella osaenae do not typically exhibit the described characteristics. Streptomyces griseus is a soil bacterium known for its antibiotic production and is not commonly associated with wound infections.
A persistent infection that is not lytic but productive is called a __________ infection.
- A. chronic
- B. latent
- C. slow
- D. transforming
Correct Answer: A
Rationale: The correct answer is A: chronic. A persistent infection that is not lytic but productive is characterized by ongoing viral replication without cell lysis. This type of infection is referred to as chronic, as it persists over an extended period. Latent infections involve periods of dormancy with intermittent reactivation. Slow infections typically have a prolonged incubation period before causing symptoms. Transforming infections lead to permanent alterations in host cell behavior. The key distinction for this question is the continuous viral replication without cell destruction, which aligns with the definition of a chronic infection.