During the skill-building session in microbiology the students need to stain the prepared and fixed sputum smears obtained from a tuberculosis patient. What staining technique should be used in this case?

Correct Answer: C

Rationale: The correct staining technique for sputum smears obtained from a tuberculosis patient is Ziehl-Neelsen staining. This technique uses carbol fuchsin dye to stain the acid-fast bacteria, such as Mycobacterium tuberculosis, red. Here's a step-by-step rationale: 1. Ziehl-Neelsen staining is specifically designed to detect acid-fast bacteria like Mycobacterium tuberculosis. 2. Carbol fuchsin dye is used to penetrate the mycolic acid layer in the cell wall of the bacteria, making them resistant to decolorization. 3. Acid-alcohol is used as a decolorizer to remove the stain from non-acid-fast bacteria. 4. Methylene blue is used as a counterstain to visualize non-acid-fast bacteria in blue. Therefore, Ziehl-Neelsen staining is the most appropriate technique for identifying Mycobacterium tuberculosis in sputum smears. Other choices like Gram, Giemsa, and

Correct Answer: C

Rationale: The correct answer is C: flagella. Flagella are whip-like structures that move fluid, mucus, or cells over the surface of a cell. They are longer and fewer in number compared to cilia, which are shorter and more numerous. Fimbriae are small, bristle-like structures that help bacteria attach to surfaces but do not move fluid. Microvilli are tiny projections that increase the surface area for absorption but do not have a role in moving fluid or cells. Therefore, flagella is the correct answer as it specifically fits the function described in the question.

Correct Answer: B

Rationale: The correct answer is B because there is no effective killed vaccine that is protective against all capsular types of Haemophilus spp. The Haemophilus influenzae vaccine primarily targets specific capsular types, not all of them. Choice A is incorrect because non-encapsulated strains can indeed be isolated from healthy carriers. Choice C is incorrect as Haemophilus influenzae is primarily transmitted through respiratory droplets, not through the air. Choice D is not correct because Choice B is indeed incorrect, making it the right answer.

Correct Answer: D

Rationale: The correct answer is D because the flu vaccine primarily stimulates systemic immunity rather than local immunity. It is administered parenterally (C) as it is injected into the body. It is a subunit vaccine (B) as it contains only specific antigens of the virus. It is a recommended vaccine (A) due to its effectiveness in preventing influenza. In summary, D is the correct choice as the flu vaccine mainly targets systemic immunity, not local immunity, unlike the other characteristics listed.

Correct Answer: A

Rationale: The correct answer is A: Staphylococcus saprophyticus. This bacterium is the second most common cause of cystitis in healthy sexually active women after E. coli. Staphylococcus saprophyticus is commonly found in the gastrointestinal and genital areas. It has a unique ability to adhere to uroepithelial cells, making it a common pathogen in urinary tract infections. Proteus mirabilis is more commonly associated with complicated UTIs, especially in catheterized patients. Pseudomonas aeruginosa is more commonly seen in hospitalized or immunocompromised patients. Klebsiella pneumoniae is typically associated with UTIs in elderly patients or those with structural abnormalities in the urinary tract.

Correct Answer: C

Rationale: The correct answer is C: Proteus mirabilis. This bacterium shows swarming on blood agar due to its ability to produce flagella and exhibit rapid and coordinated movement. Providencia stuartii and Providencia rettgeri are not known for swarming behavior on blood agar. Morganella morganii can exhibit swarming motility, but it is not as commonly associated with this characteristic compared to Proteus mirabilis, making C the most appropriate choice.

Correct Answer: A

Rationale: The correct answer is A: Blue pus bacillus. Pseudomonas genus includes bacteria that commonly cause diseases in plants. Blue pus bacillus is a common name for Pseudomonas aeruginosa, a well-known bacterium that causes diseases in medicinal plants. Explanation: 1. Blue pus bacillus (Pseudomonas aeruginosa) is a member of the Pseudomonas genus known for causing diseases in plants. 2. Colon bacillus (Escherichia coli) belongs to the Enterobacteriaceae family, not the Pseudomonas genus. 3. Proteus is a genus of the Enterobacteriaceae family, not Pseudomonas. 4. Mycoplasma is a genus of bacteria that lack a cell wall and are not related to the Pseudomonas genus. In summary, the correct answer is A because it is a member of the Pseudomonas genus known for causing diseases in medicinal plants, while

Correct Answer: C

Rationale: The correct answer is C: microbemia. When microorganisms enter the circulatory system via the lymphatic drainage, the condition is specifically termed microbemia. This term focuses on the presence of microorganisms in the bloodstream. Rationale: 1. Bacteremia (choice A) refers to the presence of bacteria in the bloodstream, not specifically microorganisms as a whole. 2. Septicemia (choice B) is a severe infection causing systemic inflammation due to the presence of pathogens or their toxins in the blood, not limited to microorganisms entering via lymphatic drainage. 3. Viremia (choice D) is the presence of viruses in the bloodstream, not a term used for microorganisms entering through the lymphatic drainage. In summary, the term microbemia accurately describes the scenario of microorganisms entering the circulatory system through lymphatic drainage, making it the correct choice over the other options.

Correct Answer: D

Rationale: The correct answer is D: interferes with protein synthesis. Cephalosporins are beta-lactam antibiotics that work by inhibiting bacterial cell wall synthesis, not protein synthesis. They are bactericidal and have a relatively broad spectrum of activity against various bacteria. Choice A, B, and C all describe characteristics of cephalosporins, making them incorrect options.