Gram-Negative Bacteria Overview
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Questions and Answers

Which species of Neisseria is responsible for gonorrhea?

  • Neisseria lactamica
  • Neisseria sicca
  • Neisseria meningitidis
  • Neisseria gonorrhoeae (correct)

What type of bacteria is Neisseria classified as?

  • Gram-negative rods
  • Gram-positive rods
  • Gram-negative cocci (correct)
  • Gram-positive cocci

Which of the following is NOT a method of transmission for Neisseria gonorrhoeae?

  • Airborne transmission (correct)
  • Sexual contact
  • Through an infected birth canal
  • Direct contact with infected fluids

Which clinical sample commonly shows N. gonorrhoeae inside polymorphonuclear leukocytes?

<p>Clinical samples from infected patients (D)</p> Signup and view all the answers

What type of organism is Neisseria meningitidis a frequent cause of?

<p>Meningitis (C)</p> Signup and view all the answers

Which of the following pairs of Neisseria species are indistinguishable under the microscope?

<p>N. meningitidis and N. gonorrhoeae (A)</p> Signup and view all the answers

What characteristic of N. gonorrhoeae defines its physical appearance?

<p>Nonmotile diplococci (B)</p> Signup and view all the answers

Neisseria gonorrhoeae is primarily associated with which type of infections?

<p>Sexually transmitted infections (D)</p> Signup and view all the answers

Which of the following genera includes organisms that can cause infections in both the gastrointestinal tract and outside of it?

<p>Salmonella (A), Yersinia (B)</p> Signup and view all the answers

What characteristic do all gastrointestinal Gram-negative rods share?

<p>They contain lipopolysaccharide (LPS). (C)</p> Signup and view all the answers

Which organism is commonly known for causing infections in the respiratory system and joints?

<p>Moraxella (D)</p> Signup and view all the answers

Which of the following pathogens is considered opportunistic?

<p>E. coli (D)</p> Signup and view all the answers

What is the primary mode of transmission for organisms causing gastrointestinal diseases?

<p>Fecal contamination (B)</p> Signup and view all the answers

Which feature is commonly associated with E. coli that aids in its pathogenicity?

<p>Fimbriae or pili (C)</p> Signup and view all the answers

Which of the following is mainly recognized for causing primarily gastrointestinal diseases?

<p>Shigella (D)</p> Signup and view all the answers

Which of the following is NOT a classic feature of acinetobacter species?

<p>They are motile. (D)</p> Signup and view all the answers

What is the primary mode of transmission for intestinal diseases caused by E. coli?

<p>Fecal/oral route via contaminated food and water (A)</p> Signup and view all the answers

Which strain of E. coli is most commonly associated with severe bloody diarrhea due to its toxin production?

<p>Enterohemorrhagic E. coli (EHEC) O157:H7 (A)</p> Signup and view all the answers

What primarily increases the severity of infections from E. coli O104:H4?

<p>Presence of verotoxin alongside enteroaggregative features (B)</p> Signup and view all the answers

What is a common cause of diarrhea in infants associated with poor sanitation?

<p>Enteropathogenic E. coli (EPEC) (C)</p> Signup and view all the answers

Which condition is commonly caused by E. coli in sterile areas of the body?

<p>Urinary tract infections (UTI) (D)</p> Signup and view all the answers

Which of the following E. coli strains leads to a dysentery-like syndrome?

<p>Enteroinvasive E. coli (EIEC) (B)</p> Signup and view all the answers

What complication is associated with infections caused by EHEC, especially strain O157:H7?

<p>Hemolytic uremic syndrome (HUS) (C)</p> Signup and view all the answers

Which mechanism is commonly utilized by Enteroaggregative E. coli (EAEC) for persistence in the host?

<p>Biofilm formation (A)</p> Signup and view all the answers

Which organism is primarily responsible for neonatal meningitis within the first month of life?

<p>E. coli (A)</p> Signup and view all the answers

What is a common symptom associated with Salmonella gastroenteritis?

<p>Fever (A), Nausea (B)</p> Signup and view all the answers

Which characteristic is true of enteric (typhoid) fever caused by Salmonella serotype typhi?

<p>It can lead to abdominal symptoms and fever. (A)</p> Signup and view all the answers

What type of lesions can Campylobacter cause in the intestine?

<p>Ulcerative inflammatory lesions (C)</p> Signup and view all the answers

What toxin is associated with Shigella species and contributes to its pathogenicity?

<p>Shiga toxin (D)</p> Signup and view all the answers

Which feature is characteristic of Vibrio organisms?

<p>Curved and rod-shaped (A)</p> Signup and view all the answers

Which of the following is a common symptom of Shigella infection?

<p>Diarrhea with blood (B)</p> Signup and view all the answers

What is the typical clinical outcome for patients suffering from enteric (typhoid) fever?

<p>Mortality of approximately 15% (A)</p> Signup and view all the answers

What disease is primarily caused by members of the genus Brucella in humans?

<p>Brucellosis (A)</p> Signup and view all the answers

Which organism is most associated with respiratory tract infections?

<p>Legionella (D)</p> Signup and view all the answers

Which of the following is NOT a known pathogen of humans?

<p>B. ovis (B)</p> Signup and view all the answers

What kind of infections does Pseudomonas aeruginosa primarily cause?

<p>Nosocomial infections (D)</p> Signup and view all the answers

Which genus is the causative agent of whooping cough?

<p>Bordetella (C)</p> Signup and view all the answers

What is the primary clinical manifestation of full-blown cholera?

<p>Profuse watery diarrhea known as rice-water stools (C)</p> Signup and view all the answers

Which species of Yersinia is known to cause bubonic plague?

<p>Yersinia pestis (B)</p> Signup and view all the answers

What type of motility is exhibited by members of the genus Helicobacter?

<p>Corkscrew motility resulting from multiple polar flagella (A)</p> Signup and view all the answers

What is the leading cause of bacterial meningitis in infants and very young children?

<p>Haemophilus influenzae (D)</p> Signup and view all the answers

Which condition is caused by the genus Bordetella?

<p>Whooping cough (C)</p> Signup and view all the answers

What is a common characteristic of pneumonic plague during epidemics?

<p>It may develop from bubonic or septicemic plague (A)</p> Signup and view all the answers

How does H.influenzae meningitis clinically present?

<p>Indistinguishable from other purulent meningitides (A)</p> Signup and view all the answers

Which species is not classified under the genus Yersinia?

<p>Yersinia cholera (A)</p> Signup and view all the answers

Flashcards

Gram-negative bacteria

A large group of bacteria characterized by a thin peptidoglycan layer in their cell walls and a presence of an outer membrane, resulting in a negative staining reaction with Gram staining.

Neisseria species

A group of gram-negative cocci (spherical-shaped) bacteria, some are pathogenic to humans, causing diseases like gonorrhea and meningitis.

Gonorrhea

A sexually transmitted infection (STI) caused by Neisseria gonorrhoeae.

Meningitis

Inflammation of the meninges (protective membranes surrounding the brain and spinal cord), often caused by Neisseria meningitidis.

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Gram-negative cocci

Gram-negative bacteria that have a spherical shape, often found in pairs (diplococci).

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Neisseria gonorrhoeae

The bacterium that causes gonorrhea, a sexually transmitted infection.

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Sexual transmission of Gonorrhoea

Gonorrhoea is primarily spread through sexual contact.

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Gram-negative rods (bacilli)

Gram-negative bacteria having rod-like shapes, which can be found as straight, curved, aerobic or anaerobic.

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Moraxella

Causes respiratory, ear, eye, CNS, and joint infections.

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Acinetobacter

A non-motile coccobacillus bacterium, often a nosocomial pathogen.

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Enteric Gram-negative Rods

Bacteria commonly found in the digestive tract, often facultative anaerobes and possessing lipopolysaccharide.

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Escherichia (E. coli)

Part of the gut microbiota, but can be pathogenic both inside and outside the digestive tract.

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Opportunistic Pathogen

A microorganism that is a normal part of the body's microbiota that can become pathogenic when the body's defenses are weakened.

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Salmonella and Shigella

Gram-negative rods primarily causing gastrointestinal diseases.

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Fecal Contamination

The presence of feces that can transmit pathogens in specific locations.

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Nosocomial Pathogen

A pathogen acquired in a healthcare facility environment.

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ETEC (Enterotoxigenic E.coli)

A common cause of traveler's diarrhea, transmitted through contaminated food/water or person-to-person contact.

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EPEC (Enteropathogenic E.coli)

A significant cause of infant diarrhea, often linked to poor sanitation.

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EHEC (Enterohemorrhagic E.coli)

Causes bloody diarrhea (hemorrhagic colitis) and potentially life-threatening kidney failure (HUS) due to toxins.

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O157:H7

The most common EHEC strain producing verotoxin.

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Urinary Tract Infection (UTI)

E.coli is the most common cause, affecting the bladder (cystitis) or kidneys (pyelonephritis).

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Extraintestinal E.coli Disease

E.coli, normally harmless in the gut, can cause disease in other parts of the body like the bladder or bloodstream.

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Enteroinvasive E.coli (EIEC)

Causes dysentery-like symptoms, with fever and bloody stools.

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Enteroaggregative E.coli (EAEC)

Causes traveler's diarrhea and persistent diarrhea in young children.

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Legionella

A genus of facultative intracellular bacteria that primarily cause respiratory infections.

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Pseudomonas aeruginosa

A widespread bacterium that acts as an opportunistic pathogen, frequently causing hospital-acquired infections.

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Brucellosis

A zoonotic disease caused by Brucella bacteria. It is spread from animals to humans.

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Tularemia

A zoonotic disease caused by Francisella tularensis, often spread through contact with infected animals.

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Bacteroides

A genus of anaerobic bacteria often associated with infections in the abdomen, specifically peritonitis.

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Neonatal meningitis cause

E. coli is a major cause of neonatal meningitis, occurring within the first month of life.

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Nosocomial infections

Hospital-acquired infections, including sepsis, bacteremia, endotoxic shock, and pneumonia.

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Salmonella diseases

Salmonella can cause gastroenteritis and typhoid fever.

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Salmonella gastroenteritis

Intestinal illness, with nausea, vomiting, diarrhea, fever, and abdominal cramps

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Typhoid fever

Severe systemic illness caused by Salmonella typhi, with fever, abdominal symptoms, and possible rash.

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Campylobacter infection

Causes acute enteritis (inflammation of the intestines) in healthy individuals.

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Shigellosis (bacillary dysentery)

Intestinal infection causing severe diarrhea with blood, mucus, and abdominal pain.

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Vibrio characteristics

Short, curved, rod-shaped bacteria.

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Cholera symptoms

Characterized by profuse watery diarrhea (rice-water stools) and massive fluid and electrolyte loss.

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Yersinia pestis

The bacterium that causes bubonic plague, a potentially fatal disease.

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Plague presentation

Can manifest as bubonic/septicemic forms or the more serious pneumonic form.

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Helicobacter characteristics

Curved or spiral-shaped bacteria with rapid corkscrew motility due to polar flagella.

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Helicobacter infections

Associated with acute gastritis and ulcers of the stomach or duodenum.

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Haemophilus influenzae

A bacterium, primarily associated with bacterial meningitis in infants and young children, often linked to otitis media.

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Bordetella pertussis

Causes whooping cough, a respiratory infection.

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Yersinia species in GI tract

Y. enterocolitica and Y. pseudotuberculosis can cause GI infections.

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Study Notes

Gram-Negative Bacteria

  • Gram-negative bacteria are a diverse group of bacteria
  • Includes cocci and bacilli forms
  • Some are straight, some are curved
  • Includes enteric bacteria, respiratory organisms, zoonotic organisms, etc.

Cocci/Coccobacilli

  • Neisseria: Contains Neisseria gonorrhoeae and Neisseria meningitidis
    • Neisseria gonorrhoeae: Causes gonorrhea, sexually transmitted
    • Neisseria meningitidis: Causes meningitis; frequently in young children
  • Moraxella: Non-motile, gram-negative coccobacilli
  • Haemophilus: Causes infections of the respiratory system
  • Bordatella: Whooping cough
  • Brucella: Brucellosis (undulant fever)

Bacilli

  • Campylobacter: Curved, spiral, or S-shaped organisms; causes gastroenteritis and enteritis, including traveler's diarrhea
  • Helicobacter pylori: Curved or spiral organisms; causes gastritis, duodenal and gastric ulcers, stomach cancer
  • Vibrio: Short, curved, rod-shaped organisms; causes cholera
  • Enterobacteriaceae: A large family, including many pathogens of GI tract as well as those causing urinary tract infections
  • Escherichia coli (E. coli): Part of the normal gut flora, but pathogenic strains exist, and can cause enteritis, meningitis
  • Salmonella: Causes gastroenteritis and enteric (typhoid) fever
  • Shigella:Causes shigellosis, characterized by bloody diarrhea
  • Klebsiella: Causes urinary tract infections, pneumonia
  • Proteus: Urinary tract infections
  • Enterobacter: Urinary tract infections
  • Serratia: Urinary tract or infections

Other Gram-Negative Bacteria

  • Legionella: Intracellular parasites; causes infections of the respiratory tract
  • Pseudomonas aeruginosa: Causes localized and systemic infections, important hospital acquired pathogen
  • Acinetobacter: Important nosocomial pathogens and cause hospital acquired infections or sepsis
  • Francisella tularensis: Causes tularemia (rabbit fever, deer fly fever)
  • Yersinia spp.: (Yersinia enterocolitica, Yersinia pestis)
    • Yersinia enterocolitica: Causes gastroenteritis and septicemia
    • Yersinia pestis: Causes plague

Gram-negative Rods

  • Bacteroides: Causes peritonitis

Overview

  • All gram-negative rods found in the GI tract of humans or animals.
  • Most are facultative anaerobes
  • Many produce LPS (endotoxin)
  • Contribute to gut microbiota
  • Transmission of pathogens often by fecal contamination.

Clinical Significance

  • Many strains are associated with different types of disease.
  • Different diseases, such as meningitis or pneumonia, are caused by varied groups of gram-negative organisms.
  • Pathogens can cause infections of intestines and urinary tract, or respiratory systems

Vaccines and Treatment

  • Available vaccines vary by particular pathogen
  • Treatment also varies with pathogen

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Related Documents

Gram Negative Bacteria PDF

Description

Explore the diverse world of gram-negative bacteria, including key genera such as Neisseria, Moraxella, and Helicobacter. This quiz covers their forms, infections caused, and characteristics, shedding light on their significance in health and disease.

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