Gram Negative Bacteria Overview

These flashcards cover essential information regarding Gram Negative bacteria, their characteristics, pathogenicity, and clinical relevance.

What are Gram Negative Bacilli known for?

They are more pathogenic.

What is a characteristic of Gram Negative bacteria?

They possess an outer membrane containing lipopolysaccharides.

What does LPS stand for?

Lipopolysaccharides.

Which Gram Negative bacterium synthesizes an unusually large number of enzymes and can metabolize a wide variety of substances?

Pseudomonas aeruginosa.

How do Gram Negative bacteria typically evade the immune system?

Through biofilm formation and possessing virulence factors.

What is an exotoxin?

A toxin secreted by bacteria that can damage host tissues.

What is an endotoxin?

A component of the Gram Negative outer membrane that can trigger strong immune responses.

Why is iron important for bacteria?

It is required for various biochemical processes for growth.

What role do fimbriae play in Gram Negative bacteria?

They assist in adhesion to host cells.

What is one of the symptoms associated with Pseudomonas aeruginosa infections?

Coughing or respiratory distress in Cystic Fibrosis patients.

What type of metabolism does Pseudomonas aeruginosa exhibit?

It can metabolize a wide range of unusual carbon sources.

How does Pseudomonas aeruginosa respond to antiseptics?

It can grow in minute traces of unusual substances, including antiseptics.

What is a biofilm?

A complex aggregation of microorganisms adhering to surfaces.

What can be a major risk factor for Pseudomonas aeruginosa infections?

Compromised immune systems in patients.

What kind of disease can Haemophilus influenzae cause?

Meningitis and other respiratory infections.

What distinguishes type B Haemophilus influenzae?

It has a capsule and is more virulent.

What is the transmission method for Haemophilus influenzae?

Respiratory droplets such as coughing and sneezing.

What does being 'fastidious' mean in relation to Haemophilus influenzae?

It requires specific nutrients and conditions for growth.

Legionella pneumophila is primarily found in what environment?

Water systems such as lakes, rivers, and plumbing.

What disease is caused by Legionella pneumophila?

Legionnaires' disease.

How does Legionella pneumophila survive within host cells?

It multiplies inside macrophages using a special secretion system.

What are the three stages of whooping cough?

Catarrhal stage, paroxysmal stage, and convalescence stage.

What does Bordetella pertussis produce that damages ciliated cells?

Tracheal cytotoxin.

What is a prominent symptom of the paroxysmal stage of whooping cough?

Violent coughing that causes a whooping sound.

Which bacteria serve as normal flora in the gut?

Enteric bacteria like Escherichia and Enterobacter.

What role do siderophores play in bacterial pathogenicity?

They scavenge iron from the host for bacterial growth.

What is the primary clinical significance of Pseudomonas aeruginosa in hospitals?

It is responsible for many healthcare-associated infections.

What effect does smoking have on the immune response to Legionella pneumophila?

It damages cilia and impairs macrophage function.

How do non-encapsulated strains of Haemophilus influenzae differ from encapsulated ones?

Non-encapsulated strains are less virulent and cause localized infections.

What is the characteristic appearance of Pseudomonas aeruginosa infections due to pigment production?

Characteristic blue-green color.

What causes the virulence of Pseudomonas infections?

Production of toxins and the ability to form strong biofilms.

How do Gram Negative bacteria typically resist antibiotics?

By having efficient efflux pumps and porin channels.

What is one of the methods by which Bordetella pertussis can be treated?

Early antibiotic intervention during initial stages.

Why do Gram Negative bacteria often show higher resistance to antibiotics?

Due to their outer membrane and specific efflux pumps.

What term describes the ability of Pseudomonas aeruginosa to use a wide variety of nutrients?

Metabolic versatility.

How does the capsule of Gram Negative bacteria affect their virulence?

Capsules enhance their ability to evade the immune system.

What is the gram reaction of Bordetella pertussis?

Gram Negative.

What is a polarly located structure in Pseudomonas aeruginosa that aids in motility?

Flagellum.

What is 'cystic fibrosis' in relation to bacteria?

A condition that compromises lung function, making it a risk factor for infections.

Which Gram Negative bacteria often require blood for growth in lab cultures?

Haemophilus influenzae.

What makes Pseudomonas aeruginosa an opportunistic pathogen?

It typically causes infections in immunocompromised individuals.

What happens to macrophages that engulf Legionella pneumonia?

They form a vacuole and the macrophage eventually bursts.

What disease can occur in untreated infections by Haemophilus influenzae?

Meningitis.

What is the clinical relevance of studying pigments like pyocyanin in Pseudomonas?

They can be used as virulence factors and indicators of infection.

What is a potential consequence of failing to clear Pseudomonas aeruginosa in CF patients?

Worsening respiratory symptoms and infection.

What can result from Bordetella pertussis infection in young children?

Broken ribs due to severe coughing.

What is the significance of fimbriae in bacterial infections?

They enhance adherence to host tissues.

How does Legionella pneumophila evade the immune system?

By surviving and replicating within macrophages.

What can excessive mucus production lead to in whooping cough cases?

Respiratory distress and complications in breathing.

What kind of infections can non-encapsulated Haemophilus influenzae cause?

Localized infections such as otitis media.

What type of patient is particularly at risk for Legionella infections?

Those with compromised immune systems.

What does the mucus in cystic fibrosis patients resemble, affecting lung function?

Thick and sticky mucus.

What is the basis of virulence in type B Haemophilus influenzae?

Presence of a capsule.

In what condition do Pseudomonas aeruginosa and other bacteria thrive?

Moist environments.

What kind of bacterium is Bordetella pertussis?

It is not opportunistic and causes whooping cough.

What effect does biofilm formation have on bacterial infections?

It makes infections harder to treat and increases resistance.

Which Gram Negative bacteria are considered opportunistic pathogens?

Many enteric bacteria, except for Salmonella and Shigella.

What type of vaccine is used to protect against Bordetella pertussis?

DTaP for children and Tdap for adults.

What are the major functions of the capsule in Gram Negative bacteria?

Protects against phagocytosis and enhances pathogenicity.

What is the infectious mechanism for Legionella pneumophila after entering macrophages?

It survives and replicates inside the Legionella-containing vacuole.

How does Pseudomonas aeruginosa contribute to the decomposition of chemicals?

By synthesizing various enzymes for metabolism.

What is a potential challenge in treating Haemophilus influenzae infections?

It requires specific growth factors from blood.

What is one primary feature of opportunistic bacteria in the gut?

Many are normal flora but can cause infections under certain conditions.

What are Pseudomonas' extracellular pigments used for?

As virulence factors and for identification in laboratory settings.

Why is Legionella pneumophila considered an intracellular pathogen?

It requires T-cell mediated immunity for effective clearance.

What can cause severe respiratory issues in Cystic Fibrosis patients when infected with Pseudomonas?

Thick mucus and impaired ciliary action.

What is one of the characteristics of Enteric bacteria?

They are often part of normal flora but can be opportunistic.

What can Legionella pneumophila do to avoid destruction by macrophages?

Block the fusion of phagosomes with lysosomes.