Chapter 20 Gram negative bacilli

The bacteria in this chapter (Gram negative bacilli) are classified based on three characteristic. The first characteristic is their oxygen requirements. Those that require oxygen are ___________ while those that can live with or without oxygen are called __________.

1. aerobes .... facultative anaerobes

Facultative anaerobes can get energy from sugars in multiple ways. Which method can facultative anaerobes use that aerobes cannot use?

fermentation

When the body fights and kills gram negative bacteria, the bacterial cells lyse, releasing the components of its outer membrane (remember the outer membrane is a structure found only in the gram negative cell wall). As the outer membrane breaks apart, the lipopolysaccharide layer releases __________ which is also called the endotoxin.

Lipid A

Release of lipid A (endotoxin) leads to a massive immune response that can cause the patient to have hypotension, tissue damage, shock, and possible death. This condition is known as

Sepsis

Which of the following gram negative bacilli are a common cause of sepsis?

Escherichia coli

Salmonella

Klebsiella

Pseudomonas aeruginosa

Enterobacter

The first group of Gram negative bacilli are aerobes. This means they do not ferment any sugars

Pseudomonas aeruginosa

Bordetella pertussis

Legionella pneumophila

Brucella abortus

Brucella suis

Francisella tularensis

Pseudomonas aeruginosa is unusual because it forms ______ colonies. Even sputum from cystic fibrosis patients with pneumonia can take on this color.

green

Which populations are most at risk for brucellosis?

veterinarians

farmers

people who drink unpasteurized milk

Brucella produces an enzyme that allows it to live in the stomach after ingestion called

urease

Bordetella pertussis produces virulence factors that allow it to attach to and debilitate these cells.

ciliated respiratory cells

The first group of Gram negative bacilli are aerobes. This means they do not ferment any sugars

Brucella suis

Bordetella pertussis

Francisella tularensis

Legionella pneumophila

Pseudomonas aeruginosa

Brucella abortus

Whooping cough caused by Bordetella pertussis has two stages. Match the stage with its description. 

1. catarrhal stagecharacterized by severe coughing fits and the "whoop" sound during inhalation.

   the first stage, a respiratory infection with nasal congestion, sneezing, and a mild cough

   2. paroxysmal stage: second stage where the coughing fits becomes severe, causing a characteristic sound as if gasping for air

The 'P' in the DTaP vaccine is to prevent against this disease.

Pertussis

The next group of Gram negative bacilli are facultative anaerobes. They also are enteric (live in the colon) and are coliforms (ferment lactose)

Escherichia coli

Serratia marcescens

Klebsiella pneumoniae

Enterobacter

Citrobacter

Strains of Escherichia coli make enterotoxins that lead to ________________ and make them ________________ strains.

diarrhea .... pathogenic

An infection with the pathogenic EHEC, which is more specifically Escherichia coli 0157:H7, can be obtained by eating __________ and is more likely to lead to a deadly condition in ____________.

undercooked ground meat .... those with lower immune system function like the children and elderly

The most dangerous pathogenic strain of Escherichia coli is EHEC, also known as Escherichia coli 0157:H7. The infection can progress from diarrhea to an infection of the _________________ called hemolytic uremic syndrome. This can be deadly, especially in the immunocompromised

1. kidney

The pathogenic EHEC strain of Escherichia coli is able to cause hemolytic uremic syndrome due to a virulence factor called ____________ which it obtained through horizontal gene transfer (Remember this from Chapter 9?) from another bacteria called Shigella.

Shiga toxin

The Escherichia coli that lives in the colon as normal flora can exit with feces and get into other body parts causing infection. In fact it is the number one cause of ____

UTIs when it enters the urethra

Since Escherichia coli lives in the colon, it will exit the body in the feces. For this reason, Escherichia coli is used as an indicator bacteria to _____________. If Escherichia coli are there, other pathogenic intestinal bacteria could be present.

determine if water, food, and dairy products are contaminated with fecal matter

Klebsiella pneumoniae is also part of the normal flora. However it can cause infection as a(n) _____________ pathogen. Infections associated with Klebsiella are commonly associated with ventilator or catheter use and include ____________.

opportunistic .... pneumonia, UTI's, or sepsis

Some enteric bacteria developed resistance to the antibiotic carbapenem

Escherichia coli

Enterobacter

Klebsiella pneumoniae

The third group of gram negative bacilli are facultative anaerobes, enteric (live in the colon), and do NOT ferment lactose

Salmonella entericia

Shigella dysenteriae

Salmonella typhi

Some individuals are asymptomatic carriers of Salmonella typhi, transmitting the pathogen through their feces. This is due to the pathogen living in their

gall bladder

Salmonella entericia

food poisoning commonly caused by undercooked eggs and poultry; can lead to sepsis

Salmonella typhi

acquired by fecally contaminated food or water, causes typhoid fever, a severe type of food poisoning that can lead to perforation of the colon and sepsis

Shigella dysenteriae

acquired by fecally contaminated food or water, typically due to poor sanitation; causes watery, bloody, and mucus-filled diarrhea called shigellosis; can lead to hemolytic uremic syndrome due to the virulence factor, shiga toxin

Gastrointestinal infection can be prevented. Learning the 5 F's can help you remember how these pathogens are transmitted and therefore help with prevention. Check which of the following is one of the 5 F's.

fingers

fomites

food

feces

flies

Half of all food borne illnesses (causing gastrointestinal infection) are due to contaminated

produce

he last group of gram negative bacilli are the facultative anaerobes that are noncoliforms and nonenterics

Haemophilus influenzae

Yersinia pestis

he first facultative anaerobe, noncoliform, and nonenteric bacteria is Yersinia pestis. A reservoir for Yersinia pestis is _____________, and transmission is through _________ .

rodents and flea bites

Yersinia pestis produces this virulence factor besides many others that lead to formation of necrotic tissue.

coagulase

Yersinia pestis causes a deadly zoonotic disease called the plague that caused pandemics throughout history.

1. bubonic plague

   fever like symptoms accompanied by swollen lymphs called buboes; can progress to a deadly form

   2. septicemic plague

   also called "Black Death" where the pathogen enters the blood, causing necrosis and gangrene and leading to death

2. pneumonic plague

    infection acquired by inhalation, resulting in a severe pneumonia that leads to death

The second facultative anaerobe, noncoliform, and nonenteric bacteria is Haemophilus influenzae. Transmission of this pathogen is through _

nhaling respiratory droplets

Haemophilus influenzae can cause cold-like symptoms but can also cause more serious infections called Haemophilus invasive diseases which are specifically

meningitis

sepsis

pneumonia

Haemophilus influenzae was the most prevalent reason for meningitis in _____________. Now it is prevented through the _________ vaccine.

Childern and HIB

Bordetella pertussis

transmission by respiratory droplets with children more affected

whooping cough (pertussis)

Pseudomonas aeruginosa

skin infections even in healthy individuals or opportunistic infections in immunocompromised such as skin infections in burn patients and chronic pneumonia in cystic fibrosis patients; also a cause of sepsis

grows in wet environments, colonizing sponges or living in hot tubs and swimming pools and transmitted through contact

Legionella pneumophila

Pontiac fever (mild form) or Legionnaire’s disease (deadly pneumonia) with males over 50 years old most likely developing the deadly form

their reservoir are aquatic environments like spas, showers, misters, and cooling towers, and they are transmitted by inhaling contaminated air

Francisella tularensis

tularemia or rabbit fever

rabbits are a common reservoir

Brucella suis

brucellosis or undulant fever, a wave-like pattern of alternating high fever and normal temperature

transmission through contact with pigs

Brucella abortus

transmission through contact with fluids from cows, bison, or elk or ingesting unpasteurized milk products
brucellosis or undulant fever, a wave-like pattern of alternating high fever and normal temperature