microbiology an introduction 12th edition test bank

Correct Answer: D

Rationale: The correct answer is D because hospital-acquired infections can be caused by a variety of microorganisms, including opportunistic pathogens and obligate pathogens such as bacteria or viruses. Opportunistic microorganisms take advantage of weakened immune systems in hospital patients, while obligate pathogens are capable of causing infections in healthy individuals. Therefore, all the choices are correct in this context as they represent potential etiological causes of hospital-acquired infections.

Correct Answer: A

Rationale: The correct answer is A: Artificial food media. Treponema pallidum is a fastidious bacterium that cannot be cultivated on artificial food media due to its complex nutritional requirements. It can be cultivated on cell lines and intratesticular in rabbits. Therefore, option A is incorrect. Option B and C are correct.

Correct Answer: B

Rationale: The correct answer is B: Klebsiella pneumoniae. This bacterium is gram-negative, capsulated, and forms lactose-positive colonies. It was first isolated in pneumonia but is more commonly associated with urinary infections, otitis, meningitides, sepsis, and nosocomial infections. Klebsiella pneumoniae fits all the characteristics mentioned in the question, making it the correct choice. Incorrect choices: A: Staphylococcus aureus is gram-positive and does not have a capsule. C: Streptococcus pneumoniae is also gram-positive and does not fit the description given. D: Mycobacterium tuberculosis is an acid-fast bacterium associated with tuberculosis, but it is neither gram-negative nor lactose-positive.

Correct Answer: B

Rationale: The Widal test is used to diagnose typhoid fever caused by the bacteria Salmonella typhi. The test detects antibodies produced in response to the bacteria. Positive results indicate a current or past infection with typhoid fever. Choice A (Syphilis) is incorrect as it is diagnosed using different tests like RPR or TPPA. Choice C (AIDS) is diagnosed with HIV tests like ELISA or Western blot. Choice D (Lyme disease) is diagnosed using tests like ELISA or Western blot specific for Borrelia burgdorferi.

Correct Answer: A

Rationale: The correct answer is A: Triatomine bug. Triatomine bugs, also known as "kissing bugs," are the specific carrier of the trypanosomes that cause Chagas disease. These bugs transmit the parasite through their feces, which contain the infectious forms of the trypanosomes. When the bug bites a human or animal, it defecates near the bite wound, allowing the parasites to enter the bloodstream through the broken skin. Mosquitoes (B) transmit diseases like malaria and dengue fever, not Chagas disease. Tsetse flies (C) are known for transmitting African trypanosomiasis (sleeping sickness), not Chagas disease. Cockroaches (D) are not known to transmit Chagas disease.