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Gram-negative bacteria are enclosed in a protective capsule. This capsule helps prevent white blood cells (which fight infection) from ingesting the bacteria. Under the capsule, gram-negative bacteria have an outer membrane that protects them against certain antibiotics, such as penicillin. When disrupted, this membrane releases toxic ...
- Larry M. Bush
- Overview
- Overview table
- What are they?
- Characteristics
- Types of Gram-positive bacteria
- Types of Gram-negative bacteria
- Treatment
- Preventing and controlling antibiotic resistance
- Summary
Gram-positive bacteria show blue or purple after gram-staining in a laboratory test. They have thick cell walls. Gram-negative bacteria show pink or red on staining and have thin walls. They release different toxins and affect the body in different ways.
Gram-positive and Gram-negative are types of bacteria.
There are many different types of Gram-positive and Gram-negative bacteria. These bacteria cause a wide range of different health issues.
People categorize gram-positive and gram-negative bacteria based on their structures and their appearance after Gram staining. Gram staining is a process of dying bacteria and then viewing them beneath a microscope.
The following table provides an overview on Gram-positive and Gram-negative bacteria:
Gram-positive and Gram-negative bacteria are two different types of bacteria.
One method that scientists use to classify bacteria is Gram staining, which is the most commonly performed laboratory procedure in microbiology.
Gram-positive
Gram-positive bacteria have the following characteristics: •Membranes: Gram-positive bacteria do not have a protective outer membrane. •Cell wall: They have a thick peptidoglycan cell wall. •Shape: Gram-positive bacteria are sphere- or rod-shaped, or they have branching filaments. •Toxins: These bacteria also contain certain toxins that can cause a number of food-borne diseases. Toxins present in Gram-positive bacteria include: •emetic toxin •diarrheal enterotoxins •neurotoxins •enterotoxin
Gram-negative
Gram-negative bacteria have the following characteristics: •Membrane: Gram-negative bacteria have two membranes — one external and one internal. •Cell wall: These bacteria also have a thinner peptidoglycan cell wall than Gram-positive bacteria, which sits between their two membranes. •Shape: They can be spherical-, rod-, or spiral-shaped. •Toxins: If something disturbs the cell wall of Gram-negative bacteria, they can release endotoxins.
Staphylococcus aureus
Staphylococcus aureus does not normally cause infection on healthy skin. If it enters the internal tissues or bloodstream, it may cause a variety of potentially serious infections. Infections it can cause include: •infective endocarditis, an infection that happens when bacteria enter the bloodstream and settles in the lining of the heart, a blood vessel, or a heart valve •skin and soft tissue infections, such as impetigo, folliculitis, and cellulitis •osteomyelitis, an infection that causes pain in the legs •septic arthritis, a type of join infection •prosthetic device infections, a complication that can happen after joint replacement surgeries •pulmonary infections: such as pneumonia •gastroenteritis, inflammation of the gastrointestinal tract that can cause vomiting and diarrhea •meningitis, inflammation of the lining that surrounds the brain and spinal cord •toxic shock syndrome, a rare and life threatening condition that happens when bacteria release harmful toxins •urinary tract infections (UTIs), an infection of the bladder, urethra, or kidneys
Staphylococcus epidermidis
Staphylococcus epidermidis can become infectious if it enters a human host. The bacteria are one of the most common causes of hospital-borne diseases in the United States. It commonly infects the skin around prosthetic devices and catheters, which can then cause blood infections to develop.
Staphylococcus saprophyticus
Staphylococcus saprophyticus commonly causes uncomplicated UTIs. This type of bacteria can also cause a number of complications such as: •acute kidney infection •urethritis, an infection that affects the urethra •epididymitis •prostatitis
Vibrio cholerae
Vibrio cholerae is a type of bacteria that causes cholera. A person usually develops cholera after the bacteria enter their body through the mouth. This type of bacteria is typically present in food or water that has been contaminated with human waste. Cholera can cause a person to experience a severe case of watery diarrhea, which can cause extreme loss of fluid and electrolytes. This may also lead to severe dehydration which can be fatal.
Escherichia coli
Escherichia coli is a type of bacteria that medical professionals often refer to as E. coli. It can cause a number of illnesses including traveler’s diarrhea and dysentery. Some cases of this infection are very mild, but others can be severe or life threatening.
Bartonella henselae
Bartonella henselae is a Gram-negative bacteria that causes cat scratch disease. A person usually contracts this bacteria after they receive a bite, scratch, or lick from a cat that has an infection, which leads to the development of cat scratch disease.
Gram-positive
Antibiotics are the main treatment for Gram-positive bacterial infections. Common antibiotics that healthcare professionals prescribe to treat these infections include: •penicillin •nafcillin •oxacillin •cloxacillin •dicloxacillin •trimethoprim •sulfamethoxazole •clindamycin •doxycycline
Gram-negative
Treatment options for Gram-negative infections can be limited. Medical professionals will often prescribe antibiotics to treat Gram-negative bacterial infections. Common antibiotics used to treat these infections include: •tetracyclines •azithromycin •ciprofloxacin •rifampin •fluoroquinolones However, the CDC notes that Gram-negative bacteria are resistant to many drugs and are becoming increasingly resistant to the currently available antibiotics.
Antibiotic resistance occurs when bacteria change and adjust in response to antibiotic medications. They can become resistant to antibiotics. This makes the antibiotics less effective or can cause them to not work at all.
The World Health Organization (WHO) states that antibiotic resistance is currently one of the biggest threats to global health, food security, and development.
The misuse and overuse of antibiotics can cause antibiotic resistance.
There are a number of things that people can do to help prevent and manage antibiotic resistance. These include:
•only using antibiotics when a medical professional prescribes them
•never demanding antibiotics if a medical professional advises against their use
Gram-positive and Gram-negative are two distinct types of bacteria.
Gram-positive bacteria appear blue or purple after Gram staining, while Gram-negative bacteria appear red or pink after gram staining.
There are many types of Gram-positive bacteria. These bacteria can cause infective endocarditis, gastroenteritis, meningitis, UTIs, impetigo, and CAP.
There are also a number of types of Gram-negative bacteria. These bacteria can cause salmonella, Legionnaires’ disease, cholera, cat scratch disease, and typhoid fever.
Bacteria are either classified as Gram-positive or Gram-negative. Their classification is based on the outcome of a test called the ‘Gram stain’. This test is named after the inventor Danish scientist Hans Christian Gram (1853–1938). The cells are stained with a purple dye (‘crystal violet’), which only binds to a substance called ...
Sep 28, 2022 · Gram positive bacteria stain purple with the Gram stain because they have a thick outer layer of peptidoglycan. Gram negative bacteria have an outer membrane that loses the purple color. Usually they are stained with a red counterstain. In microbiology, Gram positive and Gram negative are two broad classes of bacteria.
Gram-negative bacteria. Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. [ 1 ] Their defining characteristic is their cell envelope, which consists of a thin peptidoglycan cell wall sandwiched between an inner ...
Most bacteria can be broadly classified as Gram-positive or Gram-negative. Gram-positive bacteria stain purple, whereas gram-negative bacteria stain pink. This difference is due to the ability of gram-positive bacteria to retain primary stain (crystal violet) even after decolorization with acid-alcohol.
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Nov 25, 2015 · For those who like to swim and spend time in water parks and pools, the exposure to water and therefore the risk of infection is higher. Recreational water illnesses are illnesses related to recreation in water. Of these recreational water illnesses, infections are the most common because water laden with microorganisms or contaminated by human ...
