Gram Negative Bacilli, Lectures 8,9

Question 1

General Characteristics

Answer 1

• Gram negative bacilli tend to be oxidase negative and catalase positive.
• Antigen KHO, capsule, flagella, cell wall and pili
• Contain LPS endotoxin that can lead to sepsis
• Contain many exotoxins as well

Question 2

Clinically Relevant Species

Answer 2

E Coli, Salmonella, Shigella, Y Pestis, Tularemmia, Brucella, Campylobacter, H Pylori, Pertussis, Cholera, H Influenzae, Legionella, Pseudomonas

Question 3

E Coli non GI effects

Answer 3

• Leading cause of UTI and gram negatie sepsis

- Causes a large number of cases of meningitis

Question 4

E Coli - GI

Answer 4

-Food poisoning that can lead to hemolytic uremic syndrome, especially with strains expressing the shiga toxin.

Question 5

Salmonella

Answer 5

• Very common source of food poisoning 10-15%

- Typhoid Fever - Sustained bacteremia that is highly fatal.

Question 6

Shigella

Answer 6

• Common cause of food borne gastroenteritis. Bacillary Dysentery, often self limited.
• Can cause a hemolytic uremic syndrome

Question 7

Yersinia Pestis

Answer 7

• Causes the plague, which has very high mortality.
• Most commonly found in the US in the southwest.
• Carried by Mice and transmitted by fleas.
• Bipolar staining

Question 8

Tuleremia

Answer 8

-Intracellular bacteria that is transmitted by fleas that infest rabbits. Can cause pneumonia.

Question 9

Brucella

Answer 9

-Zoonotic infection that can be transmitted by a large number of animals.

Question 10

Legionella

Answer 10

• Common type of severe bacterial pneumonia.
• Contracted by exposure to contaminated water source, such as air conditioners and cooling towers.
• Causes pneumonia that can be accompanied by a GI problem as well.
• Fever without elevated heart rate.

Question 11

Bordetella Purtussis

Answer 11

• Causes whooping cough. Vaccine has greatly reduced number of cases, but a recent spike has occured because the immunity generated by the vaccine wanes.
• A catarahl stage that appears like a normal cold is the easiest to culture stage and an easy to spread stage
• Later whooping cough stage can last for a long time. Must get a nasopharyngeal swab to diagnose.
• Highly contagous

Question 12

Campylobacter Jejuni

Answer 12

• One of the four leading causes of food poisoning.
• Can cause bacteremia or sepsis
• Most common cause of Guillen Bare Syndrome.
• Campylobacter species can be transmitted from animals to humans.

Question 13

Cholera

Answer 13

• Rice water diahrrea that causes mazzive dehydration.

- Comes from water sources and also undercooked shellfish in the US

Question 14

H Infulenzae

Answer 14

• Hib vaccine has greatly reduced the number of cases of pediatric meningitis
• Can cause a host of infections including ear and throat etc.

Question 15

H Pylori

Answer 15

• Colonizes the stomach.
• Urease positive and can withstand acidic conditions.
• Causes peptic ulcers and antral gastritis.