Opportunistic Pathogens Flashcards

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1
Q

Where are OP usually found?

A

EVERYWHERE!

Pretty common, but healthy individuals can fight off

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2
Q

Who’s susceptible to OP?

A

Immunocompromised (drugs or infections)

Breach in physical barriers

Implants

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3
Q

Why have OP infections increased?

A

More surgeries

More in dwelling devices

Inc pop with chronic disease

Inc chemotherapies and immnuosurppresive agents

Use of antibiotics (clears our normal, protective flora)

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4
Q

what are the predisposing factors for OP pneumonia?

A

Lung problems, heart disease,

Surgery (particular those over 80 years)

Mechanical ventilation

Lying flat on one’s back

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5
Q

Hospital Acquired Infections

A

Nosocomial

Hand washing major factor

Usually NOP are antibiotic resistant :O

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6
Q

Biofilms

A

Formed by many OP
Dense colonies surrounded by extracellular matrix

Gives increased resistance

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7
Q

OP E. Coli

A

UTI

Bacteremia

Meningitis

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8
Q

Uropathogenic E. Coli (UPEC) Epidemiology

A

95% of nonhospital UTI
Mostly women
Catheters large source

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9
Q

UPEC Clinical Syndrome

A

10^5 bacteria/ml in urine
Usually self limiting

Cystitis (bladder inflammation) - dysuria

Acute pyelonephritis (kidney infection)
Flank pain, fever, dysuria
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10
Q

UPEC pathogenicity

A

Surface adhesions aid colonization

Different strains have different adhesion structures and are able to attack different people (not all pts equally susceptible)

P Pili help strain climb up tract and cause both cystitis and pyelonephritis

F adhesin associated with pyelonephritis

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11
Q

E. Coli Bacteremia Pathogenesis

A

Leading cause of nosocomial bacteremia

  1. Colonization of mucosal surface
  2. Translocation across surfaces into bloodstream
  3. Survival in bloodstream

Toxicity - LPS is large culprit

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12
Q

Blood stream survival

A

Capsules really important
Polysialic acid is major component

Blocks complement binding

K1 is frequent in e. Coli

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13
Q

E. Coli Meningitis

A

Leading cause in newborns

From blood to CSF, needs capsule

Siderophores and hemolysis impt for iron maintenance

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14
Q

Pseudomonas Aeruginosa

A

Infects burns, eyes, wounds, implants

Pneumonia (esp with vents)

Bacteremia in compromised patients

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15
Q

Pseudomonas a. Chronic infection

A

Cystic Fibrosis is esp susceptible

Forms biofilm

Can form slime capsule (mutant alginate strains)

Significant cause of mortality

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16
Q

Aeruginosa

A

Blue-green color (like oxidized copper)

Comes from PYOCYANIN (toxic factor)

17
Q

Pseudomonas a. Energy requirement

A

Non-fermenter

Requires aerobic incubation in lab

But in chronic infections in lives in environment with little oxygen

18
Q

Klebsiella Pneumoniae

A

Primary pneumonia when underlying medical problem present (alcoholism)
“Red current jelly” sputum

UTI, Diarrhea, Bacteremia, and Meningitis

19
Q

KP virulence factors

A

Capsule

Allows blood survival and resistance

20
Q

Enterobacter cloacae

A

Part of normal gut

Associated with burns, wounds, resp, UTI

21
Q

Serration Marcesens

A

Very common in environment
Part of enterobacteriaciae BUT more likely to infect UT or RT

Forms Biofilms

22
Q

Proteus vulgaris and mirabilis

A

UTIs

Flagella (SWARM MOTILITY)

Urease production

23
Q

Urease

A

Forms alkaline urine

  • > salt crystallization
  • chronic infection

Used for detection

24
Q

Acinetobacter baumanii

A

Who cares

25
Q

Gram negative diagnostics

A

Colony morphology (shape, size, smell)

Growth on selective media

Biochemical tests

26
Q

Treatments

A

Antibiotics will depend on microbe

Strains are developing resistance to carbapenem :0

27
Q

Prevention

A

Control of compromising factors (go less invasive, unnecessary catheters, etc)

Hand washing!

28
Q

Opportunistic Pathogens

A

Pathogens that are capable of causing disease only in “compromised” people