Question

Which of the following is true:

A) Gram-positive bacteria have a thin peptidoglycan wall and an outer membrane.
B) Some antibiotics are more effective against either gram-positive or gram-negative bacteria.
C) Gram-positive bacteria are the only cause of bloodstream infections.
D) Gram-positive bacteria are common causes of surgical site infections.

Answer 1

The correct statement is that some antibiotics are more effective against either gram-positive or gram-negative bacteria, due to the differences in their cell wall structures.

Step-by-step explanation:

The true statement among the options provided is B) Some antibiotics are more effective against either gram-positive or gram-negative bacteria. Gram-positive bacteria have a thick cell wall composed primarily of peptidoglycan and substances called teichoic acids, including lipoteichoic acids which anchor the cell wall to the cell membrane. On the other hand, Gram-negative bacteria have a thinner peptidoglycan cell wall and an outer membrane that contains lipopolysaccharides and lipoproteins. Porins are proteins that exist in the outer membrane of Gram-negative bacteria and allow the passage of substances into the cell. Gram-positive bacteria do not have an outer membrane, making statement A incorrect. Statement C is incorrect as both Gram-positive and Gram-negative bacteria can cause bloodstream infections. Lastly, statement D partly misrepresents the information, as both Gram-positive and Gram-negative bacteria can cause surgical site infections.