Which IS NOT true about sexually transmitted infections?

Correct Answer: C

Rationale: Step 1: Define sexually transmitted infections (STIs) as infections primarily spread through sexual contact. Step 2: Understand that STIs can also be transmitted through non-sexual means like blood transfusions. Step 3: Recognize that choice C is incorrect as it limits STIs to only sexually transmitted infections. Step 4: Therefore, the correct answer is C as it does not encompass all possible modes of transmission for STIs. Summary: Choices A, B, and D are incorrect as they all accurately describe the characteristics of sexually transmitted infections, while choice C is incorrect as it excludes other potential modes of transmission for STIs.

Correct Answer: A

Rationale: The correct answer is A: Alexander Fleming. He discovered the antibiotic properties of Penicillium in 1928. Fleming observed that a mold called Penicillium notatum inhibited the growth of bacteria, leading to the discovery of penicillin. Louis Pasteur is known for his work on pasteurization and microbiology, not penicillin. Joseph Lister is known for pioneering antiseptic surgery techniques. Edward Jenner is known for developing the smallpox vaccine, not penicillin. Fleming's discovery revolutionized medicine by introducing the first antibiotic, penicillin, which has saved countless lives.

Correct Answer: C

Rationale: The correct answer is C: tapeworms. Taeniasis is specifically caused by tapeworms of the Taenia species, such as Taenia solium. These parasitic worms infect the intestines of humans through consumption of contaminated food or water. Ringworms (choice A), hookworms (choice B), and pinworms (choice D) are all different types of parasites that cause distinct infections in the body, not taeniasis. Tapeworms are the only organisms among the choices that are directly associated with taeniasis due to their unique life cycle and mode of infection.

Correct Answer: A

Rationale: The correct answer is A: Treponema pallidum. This bacterium is responsible for causing syphilis due to its unique spiral shape and ability to penetrate mucous membranes. It is transmitted through sexual contact or from mother to fetus. Neisseria gonorrhoeae causes gonorrhea, Chlamydia trachomatis causes chlamydia, and Escherichia coli is a common bacterium in the gastrointestinal tract. Syphilis is distinct due to its characteristic symptoms and stages, making Treponema pallidum the correct choice.

Correct Answer: A

Rationale: The correct answer is A: Propionibacterium shermanii. This bacterium is used in the production of certain types of cheese, such as Swiss cheese, to create the characteristic holes and flavor. Propionibacterium produces carbon dioxide gas during fermentation, forming the holes in the cheese. Acetobacter aceti (B) is used in vinegar production. Giardia (C) is a parasite that causes gastrointestinal issues, not used in cheese production. Fusobacterium (D) is a type of bacteria associated with infections in humans, not used in cheese production.

Correct Answer: D

Rationale: The bacitracin sensitivity test is used to differentiate between different types of streptococci. Group A streptococci are sensitive to bacitracin, which means they will show inhibition around the bacitracin disk. This sensitivity is a characteristic feature of group A streptococci and helps in their identification. Staphylococci, pneumococci, and intestinal bacteria do not exhibit this sensitivity to bacitracin. Therefore, the correct answer is D: group A streptococci.

Correct Answer: A

Rationale: Step 1: Legionellosis is caused by the Legionella bacteria. Step 2: Legionellosis has two main clinical forms - Legionnaires disease and Pontiac fever. Step 3: Legionnaires disease presents with severe pneumonia symptoms, while Pontiac fever is a milder flu-like illness. Step 4: Therefore, the correct answer is A: Legionnaires disease and Pontiac fever. Summary: - Choice B (Skin and intestinal form) is incorrect as Legionellosis primarily affects the lungs. - Choice C (Lymphatic, lung, and intestinal forms) is incorrect as it does not accurately represent the clinical forms of Legionellosis. - Choice D (None of the above) is incorrect as Legionellosis does have specific clinical forms.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is known for producing a blue-green pigment called pyocyanin, which is characteristic of its colonies. This bacterium is commonly associated with purulent infections, especially in immunocompromised patients. Proteus vulgaris (B) is not typically associated with blue-green pigment production. Bacillus subtilis (C) is not a common pathogen in wound infections. Klebsiella pneumoniae (D) does not produce blue-green pigment and is more commonly associated with respiratory infections. Therefore, based on the clinical presentation and pigment production, Pseudomonas aeruginosa is the most likely causative agent in this case.

Correct Answer: C

Rationale: The correct answer is C: Weakly bound to the cell wall. The glycocalyx in bacteria is a protective layer that can be loosely attached to the cell wall or membrane. This loose attachment allows for flexibility and protection against desiccation and immune responses. Choice A is incorrect because the glycocalyx is not strongly bound to the cell wall, as it needs to be able to be shed easily for bacteria to escape host immune responses. Choice B is incorrect because the glycocalyx is not directly involved in bacterial movement, but rather serves as a protective barrier. Choice D is incorrect as the glycocalyx does play a role in bacterial physiology.