Which of the following microorganisms are always in a parasitic form of interaction with the individual?

Correct Answer: A

Rationale: The correct answer is A: viruses. Viruses are always in a parasitic form of interaction with the individual because they cannot survive or reproduce outside of a host cell. They rely on host cells to replicate and cause harm. Non-pathogenic bacteria (choice B) do not always cause harm and can coexist with the individual. Facultative pathogenic bacteria (choice C) can switch between being beneficial and harmful. Therefore, the correct answer is A as viruses always rely on a host for survival and reproduction.

Correct Answer: A

Rationale: The presence of acid-fast bacilli stained red using the Ziehl-Neelsen method indicates a mycobacterial infection. Among the choices, tuberculosis is the most common mycobacterial infection affecting the lungs, presenting with acid-fast bacilli in sputum. Leprosy is caused by Mycobacterium leprae, but it typically does not show up in sputum smears. Diphtheria is caused by Corynebacterium diphtheriae, which is not acid-fast. Pneumonia is a general term for lung inflammation caused by various pathogens, not specifically mycobacteria. Therefore, the correct diagnosis is tuberculosis based on the microscopy findings.

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: Botulism. The symptoms described, such as ptosis, mydriasis, anisocoria, dry mouth, and absent gag reflex, are classic signs of botulism. Botulism is caused by the bacterium Clostridium botulinum, commonly found in improperly preserved canned foods. The progression from gastrointestinal symptoms to neurological symptoms, like double vision and difficulty swallowing, is characteristic of botulism due to the toxin's effect on neuromuscular transmission. Poliomyelitis primarily affects the motor neurons and presents with different symptoms. Food toxicoinfection typically involves gastrointestinal symptoms and does not manifest with the neurological findings seen in this case. Acute ischemic stroke presents with sudden onset neurological deficits due to impaired blood flow to the brain, which is not consistent with the gradual progression of symptoms in this scenario.

Correct Answer: B

Rationale: The correct answer is B: Mycobacterium tuberculosis. This bacterium is responsible for causing tuberculosis as it specifically infects the lungs and can spread through the air. Mycobacterium leprae (choice A) causes leprosy, not tuberculosis. Streptococcus pneumoniae (choice C) is a common cause of pneumonia but not tuberculosis. Clostridium botulinum (choice D) causes botulism, a different disease unrelated to tuberculosis. Therefore, the unique characteristics and infection pattern of Mycobacterium tuberculosis make it the correct choice for the bacteria responsible for causing tuberculosis.

Correct Answer: D

Rationale: The correct answer is D (All of the above) because all three bacteria (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) are known to cause urinary tract infections. E. coli is the most common causative agent of UTIs due to its ability to colonize the urethra. P. aeruginosa can cause UTIs in hospitalized patients with catheters. S. aureus is less common but can lead to UTIs, especially in individuals with underlying health conditions. Therefore, all three bacteria are potential pathogens for UTIs. Choices A, B, and C are incorrect because each of these bacteria can individually cause UTIs, making the correct answer D.

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: A

Rationale: Step 1: A bacterial colony is a visible formation: Correct as colonies are visible to the naked eye. Step 2: Formed by clustering of cells: Correct as colonies are made up of numerous bacterial cells. Step 3: Belonging to different bacterial species: Correct as colonies can consist of one or multiple species. Summary: Choice A is correct as it accurately describes a bacterial colony. Choice B is incorrect as colonies can also form on solid nutrient mediums. Choice C is incorrect as choice A is correct. Choice D is incorrect as there is a correct option provided.

Correct Answer: C

Rationale: The correct answer is C because there is no obligatory vaccine for Neisseria meningitidis in Bulgaria. The rationale for this is that while vaccines are available for meningococcal disease, they are not mandatory in Bulgaria. Therefore, this statement is incorrect. A: This statement is correct as Waterhouse-Friderichsen syndrome can occur during meningococcemia due to rapid progression of the infection leading to adrenal gland failure. B: This statement is incorrect as Neisseria meningitidis is most common in infants, children, and adolescents, with a second peak in young adults. D: This statement is correct as Neisseria meningitidis is transmitted through respiratory secretions, such as coughing or kissing, especially in close contacts like household members or roommates.