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The OmpF-defective mutant was resistant to several antibiotics including β-lactams, suggesting that OmpF functions as the main route of outer membrane penetration for many antibiotics. In this study, we constructed mutants of all porins in Escherichia coli and examined the effect of porins on antibiotic resistance and membrane integrity. Although there are numerous studies regarding porins, a systematic approach about the roles of porins in bacterial physiology and antibiotic resistance does not exist yet. Porins are outer membrane proteins associated with the modulation of cellular permeability and antibiotic resistance. These are happening in people who are more prone to such infections as old aged people and pregnant women.A defining characteristic of Gram-negative bacteria is the presence of an outer membrane, which functions as an additional barrier inhibiting the penetration of toxic chemicals, such as antibiotics. Q.3: What infections are possible by gram-positive bacteria?Īnswer: Gram-positive bacteria are generally responsible for problems like Urinary Tract Infections. Also, their outer membranes are hidden by a slime layer and it hides the antigens present in the cell. Q.2: Which one is more harmful between gram-positive or gram-negative bacteria?Īnswer: Gram-negative bacteria are considered more harmful. Q.1: Give some examples of gram-positive bacteria.Īnswer: Some examples are Staphylococcus, Streptococcus, Enterococcus, etc. due to these bacteria.įAQs on Gram-Positive and Gram-Negative Bacteria: Some other infections also happen in the blood cells, bloodstream, wound infections, etc. Some common illness is indigestion, food poisoning, pneumonia, meningitis, etc.

Gram-negative bacteria cause many infections in humans.

Gram-positive bacteria produce exotoxins, whereas gram-negative bacteria produce endotoxins.

But do not retain the purple colored stain.

During the gram staining procedure, a gram-positive cell retains the purple-colored stain.

Whereas the cell wall of gram-negative bacteria is consisting of thin layers of peptidoglycan.

The cell wall of gram-positive bacteria is consisting of thick layers of peptidoglycan.

Some key points about Gram-Positive and Gram-Negative Bacteria:īesides the above-mentioned difference between gram-positive and gram-negative bacteria, let us have some key points. These are very susceptible to antibiotics. It is a thin layer/ often single-layered. It is a thick layer/ also can be multi-layered. The thickness of the cell wall is 8 to 10 nanometres The thickness of the cell wall is 20 to 80 nanometres The important difference between gram-positive and gram-negative bacteria in tabular form. Difference between gram-positive and gram-negative bacteria:ĭifference between gram-positive and gram-negative bacteria Due to the presence of porins, the outer membrane is permeable to nutrition, water, food, iron, etc. The periplasm is contained with proteins and degrading the enzymes. It is located in the fluid-like periplasm between the plasma membrane and the outer membrane. The peptidoglycan stays intact to the lipoproteins of the outer membrane. Whereas the outer membrane is composed of lipoproteins and phospholipids. In gram-negative bacteria, the cell wall is consisting of an outer membrane and several layers of peptidoglycan. Therefore, under a microscope, these are noticeably pink in color. The gram-negative bacteria are stained by a counterstain such as safranin, also these are de-stained with the alcohol wash. Some are gonococci causing venereal disease and meningococci causing bacterial meningitis. Mostly these bacteria include most of the bacteria normally found in the gastrointestinal tract.

This is the major characteristic of bacteria that have a cell wall composed of a thin layer of peptidoglycan. Gram-negative bacteria do not retain the crystal violet stain and further, it takes the color of the red counterstain in Gram’s method of staining. The teichoic acids are of two types, one is lipoteichoic acid and the other is the teichoic wall acid. Its cell walls additionally having teichoic acids and phosphate. Gram-positive bacteria constitute a cell wall consisting of multiple layers of peptidoglycan. Gram-positive bacteria show the visible violet color upon the application of mordant means iodine and ethanol. Also, some others are the bacterium which causes diphtheria and anthrax.

Such bacteria include staphylococci, streptococci, pneumococci. Gram-positive bacteria retain the color of the crystal violet stain in the Gram stain. 3.1.1 FAQs on Gram-Positive and Gram-Negative Bacteria: What are gram-positive bacteria?