Which of the following media is used to isolate Neisseria gonorrhoeae?
- A. Phenylethyl alcohol agar
- B. Thayer-Martin agar
- C. MacConkey agar
- D. Mannitol salt agar
Correct Answer: B
Rationale: The correct answer is B: Thayer-Martin agar. This selective media contains antibiotics that inhibit the growth of other organisms while allowing Neisseria gonorrhoeae to grow. The antibiotics in Thayer-Martin agar include vancomycin, colistin, nystatin, and trimethoprim, which target different types of bacteria, ensuring the isolation of N. gonorrhoeae. Phenylethyl alcohol agar (A) is used to isolate gram-positive organisms, not N. gonorrhoeae. MacConkey agar (C) is selective for gram-negative enteric bacteria. Mannitol salt agar (D) is used for isolating Staphylococcus species based on their ability to ferment mannitol.
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In order to prevent wound infection associated with surgical procedures a patient was given a synthetic antiprotozoan drug with a high activity against Helicobacter pylori. Specify this drug:
- A. Metronidazole
- B. Doxycycline hydrochloride
- C. Chingamin
- D. Acyclovir
Correct Answer: A
Rationale: The correct answer is A: Metronidazole. Metronidazole is a synthetic antiprotozoan drug with high activity against Helicobacter pylori, a bacterium that can cause wound infections. Metronidazole specifically targets anaerobic bacteria like H. pylori, making it effective in preventing wound infections.
Incorrect choices:
B: Doxycycline hydrochloride - Doxycycline is primarily used for bacterial infections, not protozoan infections like H. pylori.
C: Chingamin - Chingamin is not a commonly used drug for treating H. pylori infections or preventing wound infections.
D: Acyclovir - Acyclovir is an antiviral drug used to treat herpes infections, not bacterial or protozoan infections like H. pylori.
The presence of microbes in or on the body is a(n):
- A. infection
- B. contamination
- C. adhesion
- D. disease
Correct Answer: C
Rationale: The correct answer is C: adhesion. Adhesion refers to the attachment of microbes to surfaces in or on the body without causing harm. Infections (choice A) occur when microbes invade and multiply in the body, leading to harmful effects. Contamination (choice B) refers to the presence of unwanted or potentially harmful substances, not necessarily microbes. Disease (choice D) is a state of poor health caused by a specific agent, such as microbes, resulting in identifiable symptoms. In this context, adhesion best describes the presence of microbes without causing harm or leading to an infection.
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 contain the highest concentration of the virus, while nasopharyngeal swabs and cerebrospinal fluid can also contain the virus. Blood, sputum, and urine do not typically contain high levels of polio virus. Choice A is incorrect as bile content is not a common site for polio virus isolation. Choice C is incorrect because only testing feces may not provide a comprehensive picture of the infection.
A man died from an acute disease characterized by fever, jaundice, hemorrhagic rash, and acute renal insufficiency. Histological examination revealed spiral bacteria shaped like 'C' and 'S' letters. Identify the pathogen.
- A. Leptospira
- B. Treponema
- C. Borrelia
- D. Spirochaeta
Correct Answer: A
Rationale: The correct answer is A: Leptospira. Leptospira is a spiral-shaped bacterium that causes a disease known as leptospirosis, characterized by fever, jajsondice, hemorrhagic rash, and renal insufficiency. The characteristic spiral shape of the bacteria, resembling 'C' and 'S' letters, is a key identifying feature. Leptospira is commonly associated with contaminated water sources and can be transmitted to humans through contact with infected animals or water.
Summary of other choices:
B: Treponema - Treponema pallidum is the causative agent of syphilis, which does not typically present with the combination of symptoms described in the question.
C: Borrelia - Borrelia species are associated with Lyme disease and relapsing fever, but do not match the specific symptoms and histological appearance described in the question.
D: Spirochaeta - Spirochaeta is a genus of bacteria, but specific species within
The catarrhal stage of the whooping cough is characterized by:
- A. Decrease in paroxysms of coughing
- B. Subsequent respiratory infection for many months after the onset of pertussis
- C. Uncontrollable coughing followed by a high pitched 'whoop' sound
- D. Mild respiratory symptoms (mild coughing, sneezing or a runny nose)
Correct Answer: D
Rationale: The correct answer is D because the catarrhal stage of whooping cough is characterized by mild respiratory symptoms such as mild coughing, sneezing, or a runny nose. During this stage, the cough may start to worsen but is not yet severe.
A: Incorrect - Decrease in paroxysms of coughing is not seen in the catarrhal stage; it occurs later in the paroxysmal stage.
B: Incorrect - Subsequent respiratory infection for many months after the onset of pertussis is not a characteristic of the catarrhal stage.
C: Incorrect - Uncontrollable coughing followed by a high pitched 'whoop' sound is typical of the paroxysmal stage, not the catarrhal stage.