Broadspectrum antibiotics can cause various complications, including intestinal candidiasis. What drug is used for treatment of this complication?

Correct Answer: A

Rationale: The correct answer is A: Nystatin. Nystatin is specifically used to treat intestinal candidiasis because it targets and eliminates the Candida species responsible for the infection. It is not absorbed systemically, acting only locally in the gastrointestinal tract. Griseofulvin (B) is mainly used to treat fungal skin infections, not intestinal candidiasis. Undecyne (C) is an antifungal agent used for skin infections, not for intestinal candidiasis. Amphotericin B (D) is a potent antifungal agent used for systemic fungal infections, not specifically for intestinal candidiasis.

Correct Answer: B

Rationale: The correct answer is B: Cannot induce infectious disease. Saprophytes are microorganisms that obtain nutrients from decaying organic matter and do not cause infectious diseases in humans. They play a vital role in the ecosystem by decomposing dead organisms. Choice A is incorrect because saprophytes do not cause typical infections. Choice C is incorrect because saprophytes do not cause chronic infections. Choice D is incorrect because saprophytes do not cause mixed infections involving multiple pathogens. Therefore, the correct answer is B as saprophytes do not induce infectious diseases.

Correct Answer: D

Rationale: The correct answer is D: Amebiasis. The patient's symptoms of gastrointestinal disturbance and liver abscess are indicative of an infection with Entamoeba histolytica, the protozoan parasite responsible for amebiasis. The patient's travel history to an African country also increases the likelihood of contracting this disease, as it is more prevalent in tropical regions. Toxoplasmosis (A) is primarily associated with exposure to cat feces, Leishmaniasis (B) is transmitted through sandfly bites, and Malaria (C) is caused by Plasmodium parasites transmitted through mosquito bites. Therefore, these options are incorrect given the patient's presentation and travel history.

Correct Answer: B

Rationale: The correct answer is B: Penicillin. Penicillin is the drug of first choice for treating syphilis due to its effectiveness in eradicating the bacterium Treponema pallidum, which causes syphilis. It is the most reliable treatment with well-established efficacy. Gentamicin (A), ciprofloxacin (C), and chloramphenicol (D) are not recommended for treating syphilis as they are not effective against the specific bacteria causing the infection. Penicillin remains the gold standard for syphilis treatment.

Correct Answer: C

Rationale: The correct answer is C: Direct transfer of DNA between two bacterial cells. In bacterial conjugation, genetic material is transferred directly from one bacterial cell to another through a conjugative pilus. This process involves physical contact between the cells, followed by the transfer of plasmid DNA or chromosomal DNA. This mechanism allows for the exchange of genetic information between bacteria, leading to genetic diversity. Explanation of why other choices are incorrect: A: DNA transfer via bacteriophage - Bacteriophage is a virus that infects bacteria and transfers its genetic material, but this is not the mechanism involved in bacterial conjugation. B: Uptake of naked DNA from the environment - This process is known as transformation, where bacteria take up free DNA from the environment, but it is not specific to bacterial conjugation. D: Binary fission - Binary fission is a form of asexual reproduction in bacteria where a single cell divides into two identical cells, and it is not related to the process

Correct Answer: A

Rationale: The correct answer is A (Escherichia coli, Gardnerella vaginalis, and Staphylococcus aureus) because they are known to commonly cause nonsexually transmitted infections of the reproductive system. Escherichia coli can cause urinary tract infections that can ascend to the reproductive system. Gardnerella vaginalis is associated with bacterial vaginosis, a common infection of the vagina. Staphylococcus aureus can cause infections in the reproductive system through various means. Choices B, C, and D are incorrect: B: Streptococcus faecalis, Klebsiella oxytoca, and Serratia marcescens are not commonly associated with reproductive system infections. C: Clostridium tetani and Bacillus cereus are not typically involved in reproductive system infections. D: Neisseria gonorrhoeae causes sexually transmitted infections, Helicobacter pylori causes gastrointestinal issues, and Pseudomonas aeruginosa is more

Correct Answer: A

Rationale: The correct answer is A: Staphylococcus epidermidis. The presence of Gram-positive cocci in clusters indicates a staphylococcal species. The fact that the bacteria are catalase-positive and coagulase-negative further narrow it down to Staphylococcus epidermidis, as this species fits all the given characteristics. - Choice B, Staphylococcus aureus, is coagulase-positive. - Choice C, Streptococcus pyogenes, is a streptococcal species, not staphylococcal. - Choice D, Enterococcus faecalis, is a Gram-positive cocci but is catalase-negative and not typically found in clusters.

Correct Answer: B

Rationale: The correct answer is B: CMV. Patients after allogeneic stem cell transplantation are monitored for CMV reactivation due to its potential to cause severe complications in immunocompromised individuals. CMV can lead to organ damage and even mortality in these patients. Monitoring for CMV reactivation allows for early detection and prompt intervention. Incorrect Choices: A: HAV - Hepatitis A virus reactivation is not commonly monitored in post-transplant patients. C: Rubella virus - Rubella is not a common concern for reactivation in this patient population. D: Measles virus - Measles reactivation is not typically monitored in these patients.

Correct Answer: B

Rationale: The correct answer is B: lipopolysaccharides. Endotoxins are part of the outer membrane of Gram-negative bacteria, consisting of lipid A, core polysaccharides, and O antigen. Lipopolysaccharides are known to induce strong immune responses and can cause septic shock. Proteins (choice A) are components of exotoxins, not endotoxins. Teichoic acid (choice C) is found in Gram-positive bacteria, not Gram-negative bacteria. Peptidoglycan (choice D) is a major component of bacterial cell walls but is not considered an endotoxin.