Nokea
Toxicity of disinfectant against microbial cells:
- A. Is very weak
- B. Is very selective
- C. Is not selective
- D. Is temporary and more often reversible
Correct Answer: C
Rationale: The correct answer is C because disinfectants are non-selective and can harm a wide range of microbial cells. Disinfectants work by disrupting cell membranes, proteins, and nucleic acids, affecting both harmful and beneficial microorganisms. Choices A and B are incorrect because disinfectants are designed to be potent and non-selective. Choice D is incorrect because the effects of disinfectants are often permanent and irreversible on microbial cells.
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Which is correct for bacterial growth?
- A. Most of the bacteria can grow in absence or in presence of oxygen
- B. All bacteria grow in absence of oxygen
- C. All bacteria are microaerophiles
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A because most bacteria can grow in both the presence and absence of oxygen. Some bacteria are aerobic and require oxygen for growth, while others are anaerobic and can grow in the absence of oxygen. Choice B is incorrect because not all bacteria grow in the absence of oxygen. Choice C is incorrect because not all bacteria are microaerophiles, which are bacteria that require a low level of oxygen for growth. Choice D is incorrect because most bacteria exhibit flexibility in their oxygen requirements.
Each of the following statements about Neisseria meningitidis is correct, EXCEPT
- A. during meningococcemia Waterhouse-Friderichsen syndrome may be present
- B. Disease is most common in children younger than age 5
- C. There is an obligatory vaccine in Bulgaria
- D. infection is transmitted by respiratory secretions in close contacts
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.
Which of the following bacteria are capable of surviving in low-oxygen environments?
- A. Obligate anaerobes
- B. Facultative anaerobes
- C. Obligate aerobes
- D. Microaerophiles
Correct Answer: B
Rationale: The correct answer is B: Facultative anaerobes. Facultative anaerobes can survive in both oxygen-rich and oxygen-poor environments by switching between aerobic and anaerobic metabolism. They have the flexibility to use oxygen if present but can also ferment in the absence of oxygen. Obligate anaerobes (A) cannot survive in the presence of oxygen, obligate aerobes (C) require oxygen for survival, and microaerophiles (D) require low levels of oxygen for growth, unlike facultative anaerobes.
Which are the most suitable materials for isolation of polio viruses
- A. feces, duodenal and bile content
- B. blood, sputum and urine
- C. only feces
- D. feces, nasopharyngeal swabs and cerebrospinal fluid
Correct Answer: D
Rationale: The correct answer is D because polio viruses are primarily found in the gastrointestinal tract and respiratory secretions. Feces, nasopharyngeal swabs, and cerebrospinal fluid are the most suitable materials for isolating polio viruses due to their presence in these body fluids. Feces contain the virus shed from the intestines, nasopharyngeal swabs collect respiratory secretions where the virus may be present, and cerebrospinal fluid is important for detecting the virus in cases of neurological complications. Choices A and B include irrelevant body fluids that are not typically associated with polio virus transmission. Option C is too limited as the virus can also be present in respiratory secretions and cerebrospinal fluid, not just feces.
What preparations are used for prevention of fungal infection?
- A. Fluconozol, Orungal, Nisoral
- B. Rubomycin, Bleomycin, Mytomycin C
- C. Cytosar, Cormyctin, Lomycitin
- D. Captopril, Enalapril
Correct Answer: A
Rationale: The correct answer is A because Fluconazole, Orungal, and Nizoral are antifungal medications commonly used for prevention of fungal infections. Fluconazole is a systemic antifungal agent, Orungal (Itraconazole) is used for various fungal infections, and Nizoral (Ketoconazole) is effective against a wide range of fungal infections. Choices B, C, and D do not contain antifungal medications and are unrelated to preventing fungal infections.