Which bacteria are resistant to antibiotics and commonly found in hospitals?

Correct Answer: A

Rationale: The correct answer is A, Staphylococcus aureus (MRSA), because it is known to be resistant to many antibiotics commonly used in hospitals. MRSA poses a significant threat in healthcare settings due to its resistance, making it difficult to treat. Choice B, Escherichia coli, is not typically resistant to antibiotics. Choice C, Salmonella enterica, and Choice D, Vibrio cholerae, are not commonly associated with antibiotic resistance in hospitals. Therefore, A is the correct answer based on its well-documented antibiotic resistance in healthcare settings.

Correct Answer: C

Rationale: The correct answer is C: after repeated exposure for days. Subacute toxic effects typically manifest after a period of time that is longer than immediate (A) or acute (B) effects but shorter than chronic effects (D). This duration of days aligns with the definition of subacute, which refers to effects that occur gradually over a relatively short time frame. It is important to differentiate between the timing of toxic effects to accurately assess the potential harm caused by a substance. Choices A, B, and D are incorrect because they do not align with the characteristic time frame associated with subacute toxic effects.

Correct Answer: B

Rationale: The correct answer is B: Protozoans. Protozoans lack a cyst stage, which is a protective, dormant stage that allows them to survive in harsh conditions outside the host. Without a cyst stage, protozoans must be transferred quickly between hosts to avoid exposure to unfavorable environments. Molds (A) are fungi that reproduce through spores and do not have a cyst stage like protozoans. Helminths (C) are parasitic worms that have complex life cycles involving different hosts but do not rely on a cyst stage for survival. Viruses (D) are not considered protozoans and do not have a cyst stage, but they are not classified as protozoans.

Correct Answer: B

Rationale: The correct answer is B: Zoonosis. Tularemia is primarily a zoonotic disease, meaning it is transmitted from animals to humans. The bacterium that causes tularemia, Francisella tularensis, commonly infects animals like rabbits, rodents, and ticks, which serve as reservoir hosts. Humans can get infected through direct contact with infected animals, insect bites, or contaminated water or soil. This zoonotic nature of tularemia distinguishes it from anthroponosis (A), which is transmitted only between humans, and sapronosis (C), which is transmitted through non-living environmental sources. Choice D is incorrect because there is a correct answer, which is zoonosis.

Correct Answer: C

Rationale: The correct answer is C: nosocomial infections. Nosocomial infections are infections acquired in healthcare settings. This term specifically refers to infections that occur during the course of receiving medical treatment. The other choices are incorrect because: A: Incidental infections do not necessarily occur in healthcare settings. B: Accidental infections is not a commonly used term in healthcare for infections acquired in healthcare settings. D: Secondary infections refer to infections that occur as a result of a primary infection, not specifically related to healthcare settings.

Correct Answer: A

Rationale: The correct answer is A: gram-positive cocci. Staphylococci and streptococci are both types of bacteria that have a thick layer of peptidoglycan in their cell walls, which retains the crystal violet stain in the Gram staining process, making them appear purple under a microscope, hence classified as gram-positive cocci. Choice B: gram-negative cocci is incorrect as staphylococci and streptococci are not classified as gram-negative bacteria based on their cell wall structure. Choice C: spirochetes is incorrect as spirochetes are spiral-shaped bacteria with unique motility mechanisms, distinct from the spherical shape of cocci. Choice D: anaerobic gram-negative cocci is incorrect as staphylococci and streptococci are not classified as anaerobic bacteria and do not have the typical characteristics of gram-negative cocci.

Correct Answer: A

Rationale: The correct answer is A: Listeria monocytogenes. This pathogen can cross the placenta and infect the fetus, leading to serious complications. Listeria can cause miscarriage, stillbirth, or severe neonatal infections. Staphylococcus aureus and Corynebacterium diphtheriae do not typically cross the placenta. Choice D is incorrect because Listeria monocytogenes can indeed be transmitted through the placenta, unlike the other pathogens listed.

Correct Answer: B

Rationale: The correct answer is B: ribosome. Ribosomes are responsible for protein synthesis, not packaging. The Golgi complex (A) processes and packages proteins. The rough endoplasmic reticulum (rER) (C) is involved in protein synthesis and transport. Lysosomes (D) contain enzymes for digestion, not protein packaging. Therefore, ribosomes are the organelle directly involved in protein synthesis, making it the correct choice.

Correct Answer: D

Rationale: The correct answer is D because bacterial vaginitis is often caused by an imbalance in the vaginal flora, which can be disrupted by frequent douching (eliminating beneficial bacteria), tight clothing (restricting airflow), and non-breathable underwear. Avoiding tight pants and using cotton underwear allow for better ventilation, promoting a healthy vaginal environment. Infrequent douching helps maintain the natural balance of bacteria in the vagina. Choices A and B are incorrect because they recommend practices that can disrupt the vaginal flora and increase the risk of bacterial vaginitis. Choice C is partially correct but lacks the emphasis on avoiding frequent douching, which is crucial in preventing bacterial vaginitis.