Is Neisseria meningitidis Gram-negative?
Chapter 7: Identification and Characterization of Neisseria meningitidis. N. meningitidis are gram-negative, coffee-bean shaped diplococci that may occur intracellularly or extracellularly in PMN leukocytes.
Is meningitis caused by gram-negative bacteria?
Causes. Acute bacterial meningitis can be caused by different Gram-negative bacteria including meningococcal and H influenzae.
Is Neisseria meningitidis Gram positive cocci?
Meningococci (Neisseria meningitidis) are gram-negative cocci that cause meningitis and meningococcemia. Symptoms, usually severe, include headache, nausea, vomiting, photophobia, lethargy, rash, multiple organ failure, shock, and disseminated intravascular coagulation. Diagnosis is clinical, confirmed by culture.
Is meningitis caused by Gram positive bacteria?
Abstract. Primary meningitis in children is caused by two gram-negative bacterial species, Neisseria meningitidis and Haemophilus influenzae, and one gram-positive bacterial species Streptococcus pneumoniae.
What causes gram-negative bacteria?
Gram negative bacteria can pass to the body from: Medical devices that pass into the body, such as IVs or catheters. Open wounds. Contact with someone who carries gram negative bacteria.
How do you get gram-negative bacteria?
Gram-negative bacteria are most commonly spread during hand-to-hand contact in a medical care setting....PreventionWashing their hands repeatedly.Wearing gloves when needed.Keeping incisions or wounds covered.Protecting medical equipment such as catheters or ventilators and limiting use or length of use.
What does gram-negative mean in bacteria?
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation.
What are the characteristics of Neisseria meningitidis?
CHARACTERISTICS: Neisseria meningitidis belongs to the family Neisseriaceae 2. It is a Gram-negative, non-spore forming, non-motile, encapsulated, and non acid-fast diplococci, which appears in kidney bean shape under the microscope 1 3.
What are the differences between Neisseria meningitidis and Neisseria gonorrhoeae?
What is the Difference Between Neisseria Gonorrhoeae and Neisseria Meningitidis? Neisseria gonorrhoeae is an obligate human pathogen which causes gonorrhoea. On the other hand, Neisseria meningitidis is the bacterium that causes bacterial cerebrospinal meningitis.
Which of the following bacteria is gram negative?
Gram Positive vs Gram NegativeGram positive bacteriaGram negative bacteriaBacteria include all staphylococci, all streptococci and some listeria speciesBacteria include enterobacter species, salmonella species and pseudomonas speciesThick peptidoglycan layerThin peptidoglycan layer4 more rows•Aug 21, 2019
What type of bacteria is meningitis?
Meningococcal disease is any illness caused by a type of bacteria called Neisseria meningitidis. These illnesses are serious and include meningitis and bloodstream infections (septicemia).
Why is protein elevated in bacterial meningitis?
The elevation in protein is thought to be due to damage to the blood-brain barrier and leakage of serum proteins into the CSF. CSF proteins are usually highest in bacterial meningitis and can reach 1,000 mg/dL.
What are the gram-negative cocci?
The three genera of anaerobic gram-negative cocci, Acidaminococcus, Megasphaera, and Veillonella, are normal fecal flora that rarely cause disease in humans. Veillonella spp. also are part of the normal oral flora.
Is Neisseria gonorrhoeae Gram-positive or negative?
INTRODUCTION Gonorrhea, or infection with the gram-negative coccus Neisseria gonorrhoeae, is a major cause of morbidity among sexually-active individuals worldwide.
Is Staphylococcus aureus Gram-positive or negative?
Staphylococcus aureus is a gram-positive bacteria that cause a wide variety of clinical diseases. Infections caused by this pathogen are common both in community-acquired and hospital-acquired settings.
What bacteria causes Neisseria meningitidis?
Meningococcal meningitis is caused by a bacterium known as Neisseria meningitidis. There are several types, or serogroups, of Neisseria meningitidis. The most common of these serogroups are A, B, C, D, X, Y, 29E, and W135. Serogroups A, B, C, and Y are responsible for most meningococcal diseases.
Overview
Neisseria meningitidis, often referred to as meningococcus, is a Gram-negative bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life-threatening sepsis. The bacterium is referred to as a coccus because it is round, and more specifically a diplococcus because of its tendency to form pairs.
Signs and symptoms
Meningococcus can cause meningitis and other forms of meningococcal disease. It initially produces general symptoms like fatigue, fever, and headache and can rapidly progress to neck stiffness, coma and death in 10% of cases. Petechiae occur in about 50% of cases. Chance of survival is highly correlated with blood cortisol levels, with lower levels prior to steroid administration corresponding with increased patient mortality. Symptoms of meningococcal me…
Microbiology
N. meningitidis is a Gram-negative diplococcus since it has an outer and inner membranes with a thin layer of peptidoglycan in between. It is 0.6–1.0 micrometers in size. It tests positive for the enzyme cytochrome c oxidase.
N. meningitidis is a part of the normal nonpathogenic flora in the nasopharynx of up to 8–25% of adults. It colonizes and infects only humans, and has never been isolated from other animals. T…
Pathogenesis
Lipooligosaccharide (LOS) is a component of the outer membrane of N. meningitidis. This acts as an endotoxin and is responsible for septic shock and hemorrhage due to the destruction of red blood cells. Other virulence factors include a polysaccharide capsule which prevents host phagocytosis and aids in evasion of the host immune response. Adhesion is another key virulence strategy to successfully invade host cell. There are several known proteins that are involved in a…
Genome
At least 8 complete genomes of Neisseria meningitidis strains have been determined which encode about 2,100 to 2,500 proteins.
The genome of strain MC58 (serogroup B) has 2,272,351-base pairs. When sequenced in 2000, it was found to contain 2158 open reading frames (ORFs). Of these, a biological function was predicted for 1158 (53.7%). There were three major islands of horizontal DNA transfer found. Tw…
Genetic transformation
Genetic transformation is the process by which a recipient bacterial cell takes up DNA from a neighboring cell and integrates this DNA into the recipient's genome by recombination. In N. meningitidis, DNA transformation requires the presence of short DNA sequences (9–10 mers residing in coding regions) of the donor DNA. These sequences are called DNA uptake sequences (DUSs). Specific recognition of these sequences is mediated by a type IV pilin. In N. meningitidis …
Diagnosis
A small amount of cerebrospinal fluid (CSF) is sent to the laboratory as soon as possible for analysis. The diagnosis is suspected, when Gram-negative diplococci are seen on Gram stain of a centrifuged sample of CSF; sometimes they are located inside white blood cells. The microscopic identification takes around 1–2 hours after specimen arrival in the laboratory.
Prevention
All recent contacts of the infected patient over the 7 days before onset should receive medication to prevent them from contracting the infection. This especially includes young children and their child caregivers or nursery-school contacts, as well as anyone who had direct exposure to the patient through kissing, sharing utensils, or medical interventions such as mouth-to-mouth resuscitation. Anyone who frequently ate, slept or stayed at the patient's home during the 7 day…