Bacteroides & Abscesses

Question 1

Bacteroids

Answer 1

Gram -
rods
energy source complex carbs
strict anaerobes but can tolerate short exposures
intestinal flora

Question 2

Why is B. fragilis the predominant species in intra-abdominal abscesses

Answer 2

• evades phagocytosis
• tolerates the initial oxygenated environment of peritoneal cavity
• thrives once the environment becomes anaerobic

Question 3

SOD

Answer 3

Superoxide dismutase

02- + 2H—-> 02 + H202

Question 4

Bacteremia

Answer 4

presence of bacteria in the blood, with or without the presence of illness

Question 5

Sepsis

Answer 5

severe systemic illness characterized by hemodynamic derangement and multiple organ malfunction, brought on by interaction of microbial products and macrophages

Question 6

Hemodynamic Derangement

Answer 6

Circ. Sys. going ape: High cardiac output, low bp, inadequate perfusion of organs

Question 7

Mediators of Sepsis

Answer 7

IL-1 TNF-a from macrophages
host own molecules cause most of damage
LPS(gram -) peptidoglycan (gram +)

Question 8

Effects of IL-1 TNF-a

Answer 8

Vasodilation: decrease BP
vascular leakage
Intravascular coagulation–> blood clots
increased expression of neutrophil adhesion molecule–> causes tissue damage

Question 9

Treatment for sepsis

Answer 9

Administer 02, IV fluids, adrenegic drugs

Antibiotics must be used, but dead bacteria release future harmful molecules

Question 10

Spirochetes

Answer 10

Helical
Visualized by darkfield microscopy, SEM
Cause few diseases in humans
periplasmic flagella

Question 11

Treponema pallidum

Answer 11

Causes syphilis

• lack of animal model
• cant grow in lab setting

Diagnosis involves detecting antibodies against bacterium

Question 12

Primary Syphillis

Answer 12

chancre forms from immunoresponse
-increases risk of HIV infection
painless, heal on own—> already systemic

Question 13

Secondary Syphillis

Answer 13

3-6 weeks after primary
Bacterium replicates in lymph nodes, liver, joints, muscle , skin, and mucous membrane
Many variable symptoms
Lesions on one or more surfaces
**Penicillin therapy can result in fever and shock (Jarisch-Herxheimer reaction)
Symptoms resolve w/ or w/o treatment
In 2/3 of cases bacterium goes latent for decades

Question 14

Tertiary Syphillis

Answer 14

Destruction of tissues due to pressence of treponemal antigens
chronic inflammation and vasculitis
lesions
loss of motor function and dementia
death

Question 15

Borrelia burgdorferi

Answer 15

Causes lyme’s disease

• dormant in midgut of ticks
• -feed on mammal blood–> migrates to tick salivary glands

** spread facilitated by ability to bind to human plasminogen and convert to plasmin—> promotes tissue invasion

Question 16

Lyme’s Stage 1

Answer 16

Localized infection —>lesion (erythema migrans)

Question 17

Lyme’s Stage 2

Answer 17

Disseminated infection
CNS, skin, musculoskeletal affected
pain, 2o lesions, meningitis, eye and neuro abnormalities
IL-1 TNF-a cause damage

Question 18

Lyme’s Stage 3

Answer 18

Months to years after initial infection
Arthritis
memory, mood, sleep
skin lesions that lead to atrophy of skin (acrodermatitis chronica atrophicans

Question 19

Lyme’s diagnosis

Answer 19

detecting antibodies against bacterium

Question 20

Lyme’s Treatment

Answer 20

Penicillin not effective