A patient in the oral surgery department has got purulent complication. Bacteriological analysis of the wound material found a culture that produces cyan pigment. What microorganism is the most probable causative agent?

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is known for producing a bluish-green pigment called pyocyanin, which presents as a cyan pigment. This bacterium is commonly associated with wound infections and is often found in oral surgery complications. Proteus vulgaris (B) and Klebsiella pneumoniae (D) are not typically associated with cyan pigment production, making them less likely causative agents. Bacillus subtilis (C) is not known to produce cyan pigment and is not a common pathogen in wound infections. Therefore, based on the presence of cyan pigment and the clinical context of an oral surgery complication, Pseudomonas aeruginosa is the most probable causative agent.

Correct Answer: D

Rationale: The correct answer is D because all the options listed can cause respiratory tract infections. 1. Francisella tularensis can cause pneumonia. 2. Bordetella pertussis causes whooping cough, a respiratory infection. 3. Coxiella brunetti can lead to Q fever, which affects the respiratory system. Therefore, all choices are correct for causing respiratory tract infections. Choices A, B, and C are incorrect because they are individual causes of respiratory infections, whereas choice D encompasses all possible causes listed.

Correct Answer: A

Rationale: The correct answer is A: Staphylococcus aureus. Staphylococcus aureus is a Gram-positive bacterium that commonly presents as cocci in clusters. It is a known causative agent of abscesses due to its ability to produce enzymes and toxins that contribute to tissue destruction. In this case, the presence of Gram-positive cocci in clusters aligns with the characteristic morphology of Staphylococcus aureus. Summary of incorrect choices: B: Streptococcus pyogenes is a Gram-positive bacterium that typically presents as cocci in chains, not clusters. It is more commonly associated with pharyngitis and skin infections rather than abscesses. C: Enterococcus faecalis is a Gram-positive bacterium that typically presents as cocci in pairs or short chains, not clusters. It is more commonly associated with urinary tract infections and endocarditis. D: Micrococcus luteus is a Gram-positive bacterium that typically presents as t

Correct Answer: A

Rationale: Rationale: 1. Salmonella typhi causes typhoid fever, which can lead to intestinal infections. 2. Shigella flexneri causes dysentery, primarily affecting the colon. 3. Helicobacter pylori causes stomach ulcers, not intestine infections. Summary: A is correct as Salmonella typhi causes intestine infection. B and C are incorrect as they cause different gastrointestinal issues. D is incorrect as A is a valid choice.

Correct Answer: A

Rationale: The correct answer is A: Malaria. Two weeks after hemotransfusion, the onset of fever indicates a possible bloodborne infection. Malaria is a protozoal disease transmitted through infected blood, causing symptoms like fever. Toxoplasmosis, Leishmaniasis, and Amebiasis are not typically associated with fever following hemotransfusion. Malaria fits the timeline and mode of transmission in this scenario.

Correct Answer: A

Rationale: The correct answer is A: Reinfection. This is because the patient fully recovered from the initial syphilis infection after antibiotic therapy, indicating the elimination of the pathogen. Subsequently getting infected again with Treponema pallidum suggests a new exposure to the same pathogen, resulting in a new infection. Recurrence (B) would imply the reactivation of the same infection, which is not the case here. Superinfection (C) refers to a new infection that occurs on top of an existing infection, which is not the scenario described. Secondary infection (D) typically refers to an infection that occurs after an initial infection weakens the immune system, which is not the case in this scenario.

Correct Answer: C

Rationale: The correct answer is C: Reaction haemagglutination inhibition. This method is used to detect antibodies against influenza viruses by measuring the ability of the patient's serum to inhibit haemagglutination. This is a specific and sensitive technique for detecting influenza antibodies. A: Agglutination reaction is not specific for influenza viruses and may give false positives. B: Precipitation reaction in agar gel is not typically used for detecting influenza antibodies. D: Ration haemagglutination is not a standard method for detecting influenza antibodies.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Mycobacterium leprae is the correct answer as it is the bacteria known to cause leprosy. 2. Clostridium perfringens is incorrect as it is associated with gas gangrene. 3. Streptococcus pneumoniae is incorrect as it is commonly linked to pneumonia and meningitis. 4. Neisseria gonorrhoeae is incorrect as it causes gonorrhea, a sexually transmitted infection. In summary, Mycobacterium leprae is the only bacteria among the choices specifically known to cause leprosy, making it the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Botulism. The tennis racket appearance seen under the microscope is characteristic of Clostridium botulinum, the bacterium responsible for botulism. This bacterium produces spores that resemble a tennis racket shape. Botulism is a type of food poisoning caused by the ingestion of the toxin produced by Clostridium botulinum. Summary: B: Salmonellosis is caused by Salmonella bacteria, which do not exhibit a tennis racket appearance. C: Cholera is caused by Vibrio cholerae, which also does not resemble a tennis racket under the microscope. D: Dysentery is typically caused by bacteria such as Shigella or Entamoeba histolytica, neither of which exhibit the characteristic tennis racket appearance.