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HDID Block 2 > #Pseudomonas > Flashcards

#Pseudomonas Flashcards

1
Q

Describe the morphology and lab identification of Pseudomonas

A

Gram negative aerobic rod (remember the red bathtub in the sketchy video)

Non-lactose fermenting

Oxidase (and catalase) Positive (the ring and the cat)

Grows easily on many substrates

Characteristic sweet grape-like odor **on agar plate, also same smell reported on Pseudomonas infected patients with burns**

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2
Q

In what environment(s) would you find Pseudomonas?

A

Ubiquitous in the environment: Soil, water, animals, fruit, vegetables, plants

Normal flora of <10% of healthy individuals: Skin, throat, nasal mucosae, skin

Throughout hospital environment:

fluids (dialysis, ophthalmic, rinses, water taps)

equipment (whirlpools, respiratory, endoscopes, humidifiers, catheters)

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3
Q

How is Pseudomonas transmitted?

A

Transmission: fomites, aerosols, person-to-person (skin to skin contact)

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4
Q

What are the risk factors for acquiring Pseudomonas infection?

A

Causes disease where host defenses compromised

disturbed physical barriers: burns, wounds, IV lines, catheters, endotracheal tubes

immune dysfunctions: AIDS, neutropenia, hypogammaglobulinemia, complement deficiencies, iatrogenic immunosuppression

chronic lung disease particularly cystic fibrosis

**note that this is mostly an oppotunistic, nosomial infection**

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5
Q

Describe the role of the following factors in the pathogenesis of Pseudomonas:

LPS

Polysaccharide capsule

A

LPS (endotoxin):

Protects from the activity of complement

Triggers cytokine pathways -> sepsis

–

Polysaccharide capsule (slime, mucoid coat)

Interferes with phagocytes, antibodies, complement, antibiotics

Aids adherence

Elicits inflammatory cytokines

**encapsulated strains very common in CF patients**

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6
Q

What is the function of Exotoxin A in Pseudomonas pathogenesis?

A

Mode of action similar to Diphtheria toxin

Inhibits protein synthesis by transferring ADP-ribose to EF2

–

Necrotizing activity in tissue; toxic for phagocytic cells; involved in local and systemic disease

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7
Q

Describe the functions of the following Pseudomonas virulence factors:

Exoenzyme S (ExoS)

Phospholipase C

Elastase

Cytotoxin (leukocidin)

A

Exoenzyme S (ExoS): Transfers ADP-ribose of NAD to GTP binding proteins of ras superfamily

Phospholipase C - breaks down lipids, lecithin, pulmonary surfactants, erythrocytes

Elastase - degrades elastin, collagen, IgG, complement, destroys connecting tissue, fibrin, elastin, fibronectin

Cytotoxin (leukocidin) – damages membranes of PMNs and other cells

also additional proteases

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8
Q

What are the clinical manifestations of Pseudomonas? (hint: PSEUDOMONAS)

A

**for class purposes**

•Pneumonia

–HAP, CAP?

  • Bacteremia
  • Endocarditis – unusual; has high mortality
  • Skin/Soft Tissue Infections
  • Bone Infections
  • UTI
  • Otitis Externa – community acquired; aka Swimmer’s ear

Pneumonia

Sepsis

Ecthyma gangrenosum

UTIs

Diabetes

Osteomyelitis

Mucoid polysacchride capsule

Otitis externa

Nosocomial infections

Addicts

Skin infections (hot tub folliculitis, burn wound infection)

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9
Q

Describe the difference in presentation with hospital acquired pneumonia vs ventilation acquired pneumonia

A

HAP: Fevers, chills, purulent sputum, dyspnea 48 hours or more after hospitalization

VAP: fever, purulent respiratory secretions, leukocytosis, increased ventilatory requirement 48 hrs or more after endotracheal intubation

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10
Q

Describe the condition below and which bug causes it

A

Ecthyma gangrenosum

Not specific to Pseudmonas*

Usually immunocompromised patients

Perivascular bacterial invasion of media and adventitia >> ischemic necrosis

Ulceration (punched out lesion)

Raised violaceous margins

**This rash is typical of gram negative rod bacteremia**

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11
Q

Describe the condition and which bug causes it

A

Pseudomonas

#Hot tub folliculitis

Benign

Self limited

8-24 hours after exposure to contaminated water

Tender

Pruritic papules or pustules

Low grade fever

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12
Q

Describe the condition below and which bug causes it

How would you treat this bug?

A

Pseudomonas

Treatment: giving ciprofloxacin (anti-pseudomonal) as ear drops

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13
Q

Name the antibiotics you would use to treat a Pseudomonas infection

A

Piperacillin-Tazobactam

3rd/4th generation Cephalosporins: Cefepime; Ceftazidime

–

Newer Cephalosporins

Ceftazidime/Avibactam – no real benefit over Ceftazidime

Ceftolozane/Tazobactam – effective for MDR Pseudomonas

–

Aminoglycosides

Carbapenems (except Ertapenem)

Fluoroquinolones (preferably Ciprofloxacin)

Aztreonam (used if PCN allergic)

Polymyxins

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14
Q

Describe the morphology and lab characteristics of acenitobacter baumannii

A

Aerobic, non-motile, non-lactose fermenting, oxidase negative Gram neg coccobacillus

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15
Q

Acenitobacter primarily colonizes the ___, ___ and GI tract of humans, and is primarily a nosocomial pathogen

A

Colonizes skin, respiratory tract and GI tract of humans

Primarily a nosocomial pathogen particularly in the ICU

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16
Q

Unlike Pseudomonas which thrives in aqueous environments (hence how it causes hot tub folliculitis), Acintobacter can survives for long periods in ___

A

Unlike Pseudomonas which thrives in aqueous environments (hence how it causes hot tub folliculitis), Acintobacter can survives for long periods in dry conditions

17
Q

Acenitobacter can colonize ___ leading to invasive infection

A

Damaged respiratory tract

18
Q

Acenitobacter can present in ICU patients in the setting of ventilator associated pneumonia, ___ infection, ___ infecion and wound infections

A

VAP (ventilator associated pneumonia)

CAUTI (catheter-associated urinary tract infection)

CLABSI (central line-associated bloodstream infection (CLABSI))

Wound infections

19
Q

Name some of the drugs you would use to treat acenitobacter

A

Broad spectrum cephalosporin

Carbapenem

Beta lactam/beta lactamase inhibitor

Ampicillin/sulbactam

Fluoroquinolone

Aminoglycoside

Tigecycline/Eravacycline (used for MDR Gram negatives, NOT Pseudomonas)

Polymyxins

Often MDR requiring combination therapy due to poor activity of available drugs

20
Q

Other bugs commonly found in the ICU are ___ which often colonizes respiratory tract (via CF, Vents, etc), and Burkholderia cepacia, which is mostly seen in CF patients

A

Other bugs commonly found in the ICU are Stenotrophomonas maltophila which often colonizes respiratory tract (via CF, Vents, etc), and Burkholderia cepacia, which is mostly seen in CF patients

**note that for Stenotrophomonas, the drug of choice is TMP/SMX**

21
Q

Other bugs that are common flora but can become pathogenic in the ICU include E. coli, K___, E___, Proteus, Serratia and C___

These bugs typically show resistance via ___

A

E. coli, Klebsiella spp, Enterobacter, Proteus, Serratia, Citrobacter

These bugs typically show resistance via ESBLs (Extended Spectrum Beta Lactamases)

22
Q

How would you treat MDR Enterobacteraciae spp in the hospital? (which two classes of drugs work the best?)

Which drugs would you use to treat carbapenem resistant enterobacteraciae?

A

Carbapenems

Ceftolozane-tazobactam

(there’s tons of options for that 2nd question but basically ceftazidime-avibactam works the best)

23
Q

Which of the following antibiotics will treat Pseudomonas?

A.Ampicillin/Sulbactam

B.Amoxicillin

C.Ceftriaxone

D.Ceftaroline

E.Ertapenem

F.Meropenem

A

F

24
Q

A patient has been hospitalized and intubated in the ICU for 2 weeks after a GI bleed. She now has fever, increased sputum production and increase in ventilator settings. Which of the following is the optimal treatment for this patient?

A.Ampicillin-Sulbactam + Linezolid

B.Ciprofloxacin

C.Meropenem + Vancomycin

D.Piperacillin/Tazobactam

E.Cefepime + Amikacin

A

C

25
Q

Other Pseudomonas infections include ___, UTIs and eye infections

A

Osteomyelitis: Uncommon; usually puncture or surgical site (eg, sternum); Difficult to treat, high morbidity

–

UTI: usually nosocomial related to catheterization; can proceed to bacteremia

–

Eye infections: Rapidly destructive; often associated with contaminated contact lens solution

HDID Block 2 (28 decks)

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