microbiology a systems approach test bank

Correct Answer: B

Rationale: The correct answer is B because retroviruses, including those in the Family Retroviridae, have a capsid consisting of two copies of single-stranded RNA (ssRNA). This is a defining characteristic of retroviruses, which use reverse transcriptase to convert their ssRNA into DNA. This DNA is then integrated into the host cell's genome. Choices A, C, and D are incorrect because Family Retroviridae viruses are not helical non-enveloped viruses (C), they are not helical enveloped viruses (A), and they do not have a complex type of symmetry (D).

Correct Answer: A

Rationale: The correct answer is A because enteropathogenic E. coli (EPEC) have fimbrial adhesins that help them bind to enterocytes in the intestines, leading to colonization and infection. This is a key virulence factor of EPEC. Explanation for why other choices are incorrect: B: EPEC typically cause watery diarrhea in infants, not bloody diarrhea similar to shigellosis. C: EPEC are not part of the normal intestinal flora; they are pathogenic bacteria. D: EPEC are not invasive and do not typically produce enterotoxin; they primarily adhere to the intestinal epithelium.

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.

Correct Answer: A

Rationale: The correct answer is A: Dysenteric amoeba. This is because dysenteric amoebas can cause asymptomatic parasitosis, where a healthy person carries cysts that can infect others. Dysenteric amoebas are known to infect the intestines and can be transmitted through contaminated food or water. Choice B, Malarial plasmodium, causes malaria transmitted through mosquitoes. Choice C, Enteral trichomonad, causes diarrhea and is transmitted through contaminated water. Choice D, Dermatotropic leishmania, causes skin lesions and is transmitted through sandfly bites. These choices do not fit the scenario of asymptomatic parasitosis in public catering establishments.

Correct Answer: A

Rationale: The correct answer is A: Reinfection. This is because the patient fully recovered from the initial syphilis infection after antibiotic therapy, indicating the elimination of the pathogen. Subsequently getting infected again with Treponema pallidum suggests a new exposure to the same pathogen, resulting in a new infection. Recurrence (B) would imply the reactivation of the same infection, which is not the case here. Superinfection (C) refers to a new infection that occurs on top of an existing infection, which is not the scenario described. Secondary infection (D) typically refers to an infection that occurs after an initial infection weakens the immune system, which is not the case in this scenario.