ATI RN
Microbiology Chapter 12 Test Bank Questions
Question 1 of 9
Sanitary and bacteriological examination of air in drug-store premises revealed increased content of sanitary representative microorganisms. What microorganisms are these?
Correct Answer: A
Rationale: The correct answer is A (Golden staphylococcus and hemolytic streptococcus) because these microorganisms are commonly found in the air of contaminated environments like drug-store premises. Golden staphylococcus and hemolytic streptococcus are pathogenic bacteria associated with infections in humans, indicating poor sanitation. The other choices are incorrect because: B: Diphtheria and tuberculosis bacilli are not commonly found in the air in drug-store premises. C: Colon and blue pus bacilli are not typical microorganisms associated with air contamination. D: Epidermal staphylococcus and sarcina are not likely to be present in high amounts in the air of drug-store premises.
Question 2 of 9
A patient with pneumonia had a sputum culture revealing Gram-positive diplococci. The bacteria were catalase-negative and alpha-hemolytic. What is the most likely causative agent?
Correct Answer: A
Rationale: Step 1: Gram-positive diplococci suggest a pneumococcal infection. Step 2: Catalase-negative indicates Streptococcus. Step 3: Alpha-hemolysis matches S. pneumoniae's characteristics. Therefore, Streptococcus pneumoniae is the most likely causative agent. Staphylococcus aureus (B) is catalase-positive, Neisseria meningitidis (C) is Gram-negative, and Klebsiella pneumoniae (D) is not diplococci or alpha-hemolytic.
Question 3 of 9
Which one is true for the bacterial cell?
Correct Answer: D
Rationale: The correct answer is D: Multiplies by binary fission. Bacterial cells reproduce through binary fission, where a single cell divides into two identical daughter cells. This process is essential for bacterial growth and multiplication. A: The oxidative phosphorylation does not take place in the mitochondria of bacterial cells but in the cell membrane. B: Capsules are not organelles but outer protective layers found in some bacterial cells. C: Bacterial cells contain both DNA and RNA, essential for their genetic information and protein synthesis.
Question 4 of 9
The drug most often used in fighting protozoan infections of the reproductive system is:
Correct Answer: D
Rationale: The correct answer is D: metronidazole. Metronidazole is specifically effective against protozoan infections due to its ability to target and disrupt the DNA of the parasites. It is commonly used to treat infections such as trichomoniasis and giardiasis that affect the reproductive system. Ampicillin (A) and tetracycline (B) are antibiotics that target bacteria, not protozoa. Ciprofloxacin (C) is also an antibiotic that is effective against certain bacterial infections but not protozoan infections. Therefore, metronidazole is the most appropriate choice for fighting protozoan infections of the reproductive system.
Question 5 of 9
A patient presents with diarrhea and dehydration. A fecal smear stained by Gram's method revealed Gram-negative, comma-shaped bacteria. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Vibrio cholerae. Vibrio cholerae is the causative agent of cholera, which presents with severe watery diarrhea leading to dehydration. The characteristic comma-shaped (curved rod) appearance of Gram-negative bacteria is typical of Vibrio cholerae. This bacterium produces the cholera toxin, leading to the excessive secretion of fluid into the intestines. Salmonella typhi causes typhoid fever with symptoms like sustained fever, not watery diarrhea. Shigella dysenteriae causes bloody diarrhea and abdominal cramps. Escherichia coli can cause various types of infections, but typically not severe watery diarrhea like cholera.
Question 6 of 9
A patient with diarrhea had fecal analysis revealing small, curved Gram-negative bacilli with a monotrichous flagellum. These bacteria do not form spores or capsules and thrive in alkaline conditions. What is the causative agent?
Correct Answer: A
Rationale: Step 1: Small, curved Gram-negative bacilli with a monotrichous flagellum point towards a motile bacterium. Step 2: The absence of spores or capsules and preference for alkaline conditions further narrows down the possibilities. Step 3: Vibrio cholerae fits all criteria as it is a curved, motile, Gram-negative bacillus that thrives in alkaline environments. Summary: Escherichia coli is a facultative anaerobe, Salmonella and Shigella are non-flagellated, and all of them can form capsules or spores, unlike Vibrio cholerae.
Question 7 of 9
For Parvovirus B19 is true that:
Correct Answer: C
Rationale: The correct answer is C because Parvovirus B19 causes erythema infectiosum, also known as fifth disease. This virus primarily affects children and causes a distinctive red rash on the cheeks, arms, and legs. It is not associated with causing HBV (Hepatitis B Virus), AIDS, or measles. Parvovirus B19 specifically targets red blood cell precursors, leading to anemia in some cases. Understanding the characteristic clinical presentation and pathophysiology of the virus helps in selecting the correct answer.
Question 8 of 9
Immunosuppressive drugs are not used for:
Correct Answer: B
Rationale: The correct answer is B: Measles. Immunosuppressive drugs are not used for treating viral infections like measles as they target the immune system and can worsen the infection. Organ transplantation requires immunosuppressive drugs to prevent organ rejection. Autoimmune diseases involve an overactive immune response, so immunosuppressive drugs are used to reduce this response. Hemolytic disease of the newborn can be treated with immunosuppressive drugs to prevent the destruction of red blood cells.
Question 9 of 9
When cultured on solid growth media, bacteria with long O-specific chains form:
Correct Answer: A
Rationale: The correct answer is A: Smooth S colonies. Bacteria with long O-specific chains are known as smooth strains, and when cultured on solid growth media, they form smooth colonies due to the presence of the O antigen. This gives them a glossy appearance. Rough R colonies (Choice B) lack O antigen and appear rough. Mucoid -M colonies (Choice C) are associated with capsules, not O-specific chains. H colonies (Choice D) are not relevant to the O-specific chains. Smooth S colonies are the characteristic phenotype of bacteria with long O-specific chains when cultured on solid media.