Microbiology Chapter 1 Test Bank

Correct Answer: A

Rationale: The correct answer is A: Haemolytic streptococci. Hemolytic streptococci are known to cause serious infections in humans, including strep throat and skin infections. These bacteria have the potential to spread rapidly and cause epidemics. Bacilli are a broad category of bacteria and not all are necessarily harmful. Micrococci are commonly found on human skin and are generally harmless. Yeast fungi are also commonly found in the environment and are not typically associated with causing epidemics. Therefore, the presence of hemolytic streptococci in the air of a pharmacy indicates a direct epidemic danger due to their pathogenic nature and potential to cause widespread infections.

Correct Answer: B

Rationale: The correct answer is B: Typhoid fever, Brucellosis. Both Typhoid fever and Brucellosis are bacterial infections that can lead to bacteremia, the presence of bacteria in the bloodstream. In Typhoid fever, the causative agent Salmonella typhi can enter the bloodstream, causing bacteremia. Similarly, Brucellosis, caused by Brucella species, can also result in bacteremia. Choice A is incorrect because bacteremia is not typically observed in Diphtheria. Choice C, Cholera, is caused by a toxin-producing bacterium and does not usually lead to bacteremia. Choice D, Dysentery, is a condition characterized by bloody diarrhea and is primarily caused by parasites or bacteria that typically do not lead to bacteremia.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Mycobacterium tuberculosis is the causative agent of tuberculosis. 2. Mycobacterium tuberculosis is a slow-growing, acid-fast bacterium. 3. It primarily infects the lungs and can spread to other parts of the body. 4. Bacillus anthracis causes anthrax, Clostridium tetani causes tetanus, and Treponema pallidum causes syphilis. 5. Therefore, choice A, Mycobacterium tuberculosis, is the correct answer for the bacteria responsible for tuberculosis.

Correct Answer: B

Rationale: Gas gangrene is caused by Clostridium perfringens due to its ability to produce gas in tissues leading to necrosis. Other choices are incorrect: A (C. difficile causes diarrhea), C (C. tetani causes tetanus), and D (incorrect as B is the causative agent).

Correct Answer: C

Rationale: The correct answer is C: Biological test, bacteriological. Botulism is caused by the toxin produced by Clostridium botulinum bacteria. To diagnose botulism, biological tests such as detecting the toxin in patient samples and bacteriological tests to identify the bacteria are crucial. These tests confirm the presence of the bacteria and its toxin, providing a definitive diagnosis. Choice A is incorrect as it does not specify any relevant diagnostic methods. Choice B is incorrect because mycological tests are not relevant for diagnosing botulism caused by a bacterial toxin. Choice D is incorrect as allergic tests and serological tests are not used for diagnosing botulism.