ATI RN
microbiology chapter 1 test bank Questions
Question 1 of 9
A patient with a respiratory infection had sputum cultured on Endo agar, revealing green colonies. The bacteria were Gram-negative rods. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is known to produce green colonies on Endo agar due to its pyoverdin pigment. It is also a Gram-negative rod. P. aeruginosa commonly causes respiratory infections in immunocompromised patients. Escherichia coli (B) typically produces pink colonies on Endo agar and is more associated with gastrointestinal infections. Salmonella typhi (C) and Shigella dysenteriae (D) are both Enterobacteriaceae that usually do not produce green colonies on Endo agar and are more associated with gastrointestinal infections as well.
Question 2 of 9
During the regular sanitary epidemiological inspection of a pharmacy, the bacteriological analysis of air was performed. The air was found to have bacilli, yeast fungi, hemolytic streptococci, micrococci. Which of the detected microorganisms indicate the direct epidemic danger?
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.
Question 3 of 9
A fecal sample cultured on Endo agar produced red, lactose-positive colonies. What microorganism is most likely present?
Correct Answer: A
Rationale: The correct answer is A: Escherichia coli. On Endo agar, lactose-fermenting bacteria produce red colonies due to acid production. Escherichersia coli is a lactose-fermenting, gram-negative bacillus commonly found in the intestines. Salmonella and Shigella are lactose-negative and do not produce red colonies on Endo agar. Proteus is also lactose-negative and doesn't typically grow on Endo agar. Therefore, based on the lactose fermentation and colony color, Escherichia coli is the most likely microorganism present in the fecal sample.
Question 4 of 9
In which of the following GIT infections, the pathogenesis consists mainly of invasion and intraepithelial multiplication without generalization of infectious process:
Correct Answer: C
Rationale: Rationale: 1. Shigella invades and multiplies within the intestinal epithelial cells, causing inflammation and tissue damage locally. 2. It does not spread systemically, unlike Yersinia enterocolitica and Listeria monocytogenes. 3. Shigella's pathogenesis is focused on invasion and multiplication at the site of infection, leading to symptoms of dysentery. 4. Yersinia enterocolitica and Listeria monocytogenes can disseminate beyond the gastrointestinal tract, causing systemic infections. Summary: - A (Yersinia enterocolitica) and B (Listeria monocytogenes) are incorrect as they can generalize the infectious process. - C (Shigella) is correct as it mainly involves invasion and intraepithelial multiplication without spreading systemically.
Question 5 of 9
A 14-year-old boy was diagnosed with Hutchinson's triad: barrel-shaped teeth, parenchymatous keratitis, and deafness. These signs are characteristic of:
Correct Answer: A
Rationale: The correct answer is A: Syphilis. Hutchinson's triad is a classic presentation of congenital syphilis. Barrel-shaped teeth, parenchymatous keratitis, and deafness are hallmark signs. These occur due to infection of the fetus by the spirochete Treponema pallidum. Syphilis can lead to various systemic manifestations, including skeletal abnormalities, skin lesions, and neurological complications. Opisthorchiasis, Toxoplasmosis, and Tuberculosis do not typically present with the specific triad described in the question. Opisthorchiasis is a parasitic infection, Toxoplasmosis is caused by a protozoan, and Tuberculosis is a bacterial infection that primarily affects the lungs.
Question 6 of 9
Which of the following structures is shaped like a hollow cylinder made out of tubulin proteins?
Correct Answer: B
Rationale: I apologize for the confusion, but the correct answer to the question is actually A: microtubules. Microtubules are indeed shaped like hollow cylinders made out of tubulin proteins. They play a crucial role in cell structure, cell division, and intracellular transport. Microfilaments (choice B) are composed of actin proteins and are not shaped like hollow cylinders. Intermediate filaments (choice C) are more rope-like in structure and are made up of various proteins. Flagella (choice D) are whip-like structures used for cell movement and are not shaped like hollow cylinders.
Question 7 of 9
A patient with a respiratory infection had sputum cultured on Endo agar, revealing green colonies. The bacteria were Gram-negative rods. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is known to produce green colonies on Endo agar due to its pyoverdin pigment. It is also a Gram-negative rod. P. aeruginosa commonly causes respiratory infections in immunocompromised patients. Escherichia coli (B) typically produces pink colonies on Endo agar and is more associated with gastrointestinal infections. Salmonella typhi (C) and Shigella dysenteriae (D) are both Enterobacteriaceae that usually do not produce green colonies on Endo agar and are more associated with gastrointestinal infections as well.
Question 8 of 9
Which is the preferred mode of transmission of HIV from a mother to a child?
Correct Answer: D
Rationale: The correct answer is D: All of the above. HIV can be transmitted from mother to child during delivery through mixing of blood, during pregnancy through the placenta, and via breastmilk during lactation. Each mode of transmission carries a risk of HIV transmission to the child due to the presence of the virus in the mother's blood and bodily fluids. It is important to note that all three modes contribute to the risk of mother-to-child transmission of HIV, and preventive measures should be taken to reduce this risk. Option A, during delivery through mixing of blood, is correct as HIV can be transmitted through exposure to infected blood during childbirth. Option B, during pregnancy through placenta, is also correct as the virus can cross the placenta and infect the fetus. Option C, via breastmilk during lactation, is correct as HIV can be present in breastmilk and transmitted to the child through breastfeeding. Therefore, the preferred mode of transmission of HIV from a mother to a child
Question 9 of 9
Which one is true about the laboratory diagnosis of urinary tract infections
Correct Answer: D
Rationale: The correct answer is D because it encompasses the true statements regarding the laboratory diagnosis of urinary tract infections. A: Bacteriuria of less than 10^5 can be significant in treated patients due to the development of antibiotic resistance. B: Staphylococcus aureus, Salmonella typhi, and Mycobacterium tuberculosis may be significant regardless of quantity due to their pathogenic nature. C: Leukocyturia indicates inflammation, and even a lower number of leukocytes can be clinically significant. Therefore, option D covers all these aspects making it the correct choice.