Microbiology/ pharmacology Flashcards

(58 cards)

1
Q

What type of toxins do GPC and GNR have?

A

GPC have exotoxins, GNR have endotoxins.

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2
Q

What is the treatment for VAP?

A

VAP treatment is vanc + Cefepime. Add another pseudomonal coverage if high risk for MDR for 7 days.

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3
Q

What is the most common organism in central line infections?

A

Staph epidermidis is the most common organism in central line infections, staph aureus #2

Also Staph epidermidis:
- MC organism in peritoneal dialysis catheter infection (peritonitis)
- MC organism in AV graft infection
- MC organism MC late AAA graft infection
- MC organism in blood product contamination

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4
Q

What is the most common organism in VAP?

A

Staph aureus is the most common organism in VAP.

Also staph aureus:
- MC organism in surgical wound infections
- MC organism in osteomyelitis
- MC organism in peritoneal dialysis catheter infection (exit site and tunneled catheter infection) NOT peritonitis
- MCC of lung abscess
- MCC of mycotic aneurysm
- MC organism overall and MC for early (<2 weeks) AAA graft infection
- MC organism in Superficial and suppurative thrombophlebitis

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5
Q

What is the most common organism in intra-abdominal abscess?

A

The most common organism in intra-abdominal abscess is Enterococcus faecalis (GPC), E. Coli (GNR), and B. Fragilis (anaerobic).

Broad spectrum abx is recommended for intra-abdominal abscesses with: diabetes, sepsis, fever, WBC, cellulitis, any hardware

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6
Q

What should be done in the presence of bacteremia from non-cuffed catheters?

A

All non-cuffed catheters should be removed.

  • bacteremia due to S. aureus, Pseudomonas, or Candida infection and with other access options, we recommend immediate removal of the cuffed catheter and placement of a temporary catheter into another site
  • Remove all catheters that have exit site infection or pus
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7
Q

What is the most potent trigger of TNF-alpha in E. coli during gram-negative sepsis?

A

Endotoxin, specifically Lipid A, is the most potent trigger of TNF-alpha in E. coli.

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8
Q

Necrotizing soft tissue infections

A

MC polymicrobial
Can present rapidly after surgery (POD 0-2)
Group A beta hemolytic strep pyogenase, staph aureus, clostridium perfringens
Type I = polymicrobial = MC. Staph, strep, pseudomonas, enterococcus, etc

Type II = monomicrobial – two types
1. Monobacterial - #1 MC is Group A Beta hemolytic strep = Strep PYOGENES, Releases exotoxin A + C.
2. Monobacterial - Staph aureus also has exotoxin.

Type III = Clostridium perferingens, vibrio vulnificus (Seafood, boats)
Wound biopsy for type II (monocrobial) will show GPC with paucity of PMNs
Tx: broad spectrum abx until organism identified. Strep pyogenase, or Clostridium Perferingens: high dose PEN G + clindamycin

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9
Q

What is the best method to diagnose osteomyelitis?

A

MRI is the best to diagnose osteomyelitis.

Staph aureus MC. If cannot get MRI (metal): 3 phase bone scan (Technetium-99). Don’t get bone biopsy in patients with diabetic infections and ulcers: can seed infection into bone
- Tx: abx X 6 weeks and debridement

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10
Q

What is the initial treatment for Clostridium difficile?

A

Initial treatment for severe or non-severe is oral vanc or fidaxomicin for 10 days.

  • Initial recurrence: fidaxomicin (BEST) OR oral vanc pulsed regimen then tapered dose for 21 days
  • If fidaxomicin or metronidazole was used then Vancomycin 125 mg orally 4 times daily for 10 days
  • Second recurrence: fidaxomicin OR oral vanc as above
  • Stool transplant only for third recurrence
  • Severe colitis: Oral vanc + IV flagyl.
  • Add rectal vanc of patient has ileus
  • Fulminant colitis – shock with requirement of pressors OR for subtotal colectomy with end ileostomy
  • For active C. diff infection diagnosis: Toxin A or B must be present. (can also be colonized)
  • Dx: best is PCR to detect toxin producing genes. MC used. Rapid, sensitive, and high NPP. However, cannot distinguish colonized vs infection. High FP
  • Stool culture  followed by a test to detect toxin producing gene or toxin itself
  • Most sensitive test
  • Takes days to complete, not a good test
  • ELISA (enzyme immunoassay) for Toxin A and B: Used for decades, now found to be insensitive
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11
Q

What is the recommended treatment for candidemia?

A

Anidulafungin is the best treatment for candidemia.

Also: micafungin, caspofungin

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12
Q

What is the most common organism found in human bites?

A

The most common organism is Strep pyogenes, but Eikenella is only found in human bites. Tx: augmentin and tetanus vaccine

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13
Q

What is the recommended treatment for human bite lacerations?

A

Do not close wounds primarily; they need wash out and heal by secondary intention.

High infection rate.
Risk for Eikenella corrodens Infection
Px abx only given to wounds on hands and face or near a joint

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14
Q

What is the common organism in surgical site infections?

A

The most common organism in surgical site infections is Staph.

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15
Q

What is the recommended antibiotic for Enterococcus?

A

The best initial treatment is ampicillin.

Can use vanc. If VRE: linezolid.

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16
Q

What is the significance of peak and trough levels in vancomycin and gentamicin?

A

Vancomycin: peak should be 20-30, and trough should be 5-10.
Gentamicin: peak 6-10, trough <1

Peak too high: decrease amount of each dosage. (Don’t get peak levels for vanc or aminoglycoside, not recommended)
Trough too high: Increase the length interval between doses

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17
Q

What is the definition of zero-order kinetics?

A

Zero-order kinetics means a constant amount of drug is eliminated regardless of dose.

-Alcohol is zero order

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18
Q

What is the definition of ED50?

A

ED50 is the drug level at which the desired effect occurs in 50% of the population.

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19
Q

Skin infection with lymphedema organism

A

Streptococcus

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20
Q

Hyperglycemia in sepsis and insulin

A

Hyperglycemia in sepsis: Early: low insulin, high glucose (impaired utilization). Late: high insulin, high glucose, due to insulin resistance

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21
Q

C. Perfringens

A

C. Perfringens - Clostridium myonecrosis – gas gangrene: Occurs with farming accident.
* Alpha toxin - major source of morbidity and mortality; cytotic to PMNL
* Also theta toxin

-Destruction of healthy muscle and soft tissues; trauma -> vascular compromise= anaerobic environment

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22
Q

SBP in children

A

MC due to nephrotic syndrome. MC organism is strep pyogenase

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23
Q

Clean wound <2% infection

A

-primarily closed
- No inflammation, infection, GU, GI, resp tracts are NOT entered
- Mastectomy, hernia, thyroidectomy, vascular bypass, CABG,

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24
Q

Clean contaminated 5-10% infection

A

Clean contaminated 5-10% infection – controlled entry into tracts: primarily closed
- GU, GI, resp, tracts entered in controlled fashion. No spillage.
- No inflammation!!!!!!!!!!! Nothing acute here. No infection. No acute appy or acue chole.
- Colectomy, biliary colic, urologic procedures, hemorrhoidectomy, appy that is elective non inflamed

25
Contaminated 10-20% infection
– secondary intention OR delayed primary closure - Open fresh accidental wounds < 4 hours - Major break in sterile technique - Gross spillage of GI content - Entering GU or biliary tract in presence of infection - Acute NON-purulent inflammation encountered - E.g. Acute appendicitis, acute cholecystitis, Diverticulitis, GSW to colon repair, bile spillage
26
Dirty wound >30% infection
Dirty wound >30% infection – secondary intention - Perforated viscera prior to operation. - ABCSESS, pus, Infection. - Wounds > 4 hours
27
Elective laparoscopic chole abx
Elective laparoscopic chole does not require preop abx, if no acute chole, no episodes of biliary colic < 30 days, CBD stones, no recent ERCP, no stone or GB spillage. Open chole all require abx px
28
Oral carbohydrate loading prior to surgery
Drink carb liquid 2 hours before surgery decreases insulin resistance No decrease risk of SSI
29
Modifiable risk factors that reduce SSI:
Modifiable risk factors that reduce SSI: - Glycemic control, obesity, smoking, alcohol, prealbumin levels - A1c does not affect SSI numbers. Only periop glucose levels
30
Proven to reduce SSI
Proven to reduce SSI - Cessation of smoking 4-6 weeks before surgery - Glucose control target 110-150 - Avoid hair removal  if have to, use clippers - Alcohol based prep unless mucosa - Abx within 1 hour of incision - Normothermia - Use wound protectors - Abx suture – troclosan reduce SSI - Supplemental oxygen periop Not been proven to reduce SSI but recommended - Bathing with chlorhexidine - All surgical attire
31
CLABSI
CLABSI – central line infections - Best is subclavian vein, 2nd is IJ, last is femoral - Abx impregnated catheters decrease CLABSI rate - Chlorhexidine impregnant dressings decrease CLABSI rate - Sutureless retention device should be used  decrease CLASBI rate
32
Viral hepatitis
Hepatitis B, C, and D can cause chronic hepatitis and hepatoma Hepatitis A, B, C, D+B, and E can cause acute and fulminant hepatitis (very rare with A + C) Hepatitis A: serious consequences uncommon Hepatitis B (DNA* only one that is DNA): Anti-HBc-IgM (c=core) elevated in first 6 months, then IgG takes over; vaccination: increased anti-hBs (s=surface) antibodies Hepatitis C (RNA): can have long incubation period; Tx: Sovaldi (95% cure rate) Hepatitis D is cofactor for B = these two combined have highest mortality Hepatitis E = fulminant hepatic failure in pregnancy; most often 3rd trimester
33
Post exposure prophylaxis HIV:
HAART (Raltegravir + Tenofovir) initiate therapy immediately X 4 weeks. ELISA at time (patient and exposure source) of exposure and at 4 weeks
34
Candida endophthalmitis
Candida endophthalmitis – liposomal amphotericin
35
Actinomyces
Not a true fungus, it’s an anaerobe. MC causes abscesses in head and neck. Often has a draining sinus that produces sulfur granules. Tx: penicillin G and drainage
36
Nocardia
Nocardia– gram positive rod, mimics fungus, branched filamentous morphology, Causes PNA, endocarditis. Tx: bactrim
37
Brown recluse spider tx
Brown recluse spider tx: Tetanus shot. Don’t give dapsone, not studied. Avoid early surgery
38
Impetigo, erysipelas, cellulitis, folliculitis MC organism
staph
39
MCC of infectious proctitis
MCC of infectious proctitis – STD: gonorrhea Proctitis= inflammation of rectum/ anus
40
Tetanus wound prophylaxis
Contaminated = dirt, poop, soil, saliva, puncture wounds, avulsions, GSW, crush, burn, frostbite All burns, frostbite, animal, snake and human bite, feces, saliva, dirt, soil are considered contaminated Tetanus immunoglobulin – give to contaminated wounds with unknown vaccines or < 3
41
Flagyl
Flagyl - produces oxygen radicals that break up DNA
42
Sulfonamides
– has PABA analogue, inhibits purine synthesis
43
Trimethropin
Trimethropin – inhibits dihydrofolate reductase: inhibits purine synthesis
44
Bacteriostatic
Bacteriostatic – tetracycline, clindamycin, macrolides, Bactrim
45
Carbapenems
Carbapenems -Meropenem, imipenem -Broad spectrum: GPC, GNR, anaerobes -Given with cilastatin: prevents renal hydrolysis and increases half-life -SE: seizures –Not effective for MEP: MRSA, enterococcus, proteus
46
Inhibitors of cell wall synthesis
Inhibitors of cell wall synthesis - penicillin, cephalosporins, carbapenems, vanc, monobactam
47
Inhibit 30S ribosome
Inhibit 30S ribosome - Tetracycline, aminoglycoside Aminoglycoside: gentamicin, tobramycin
48
Inhibit 50S ribosome
Inhibit 50S ribosome - macrolides (erythromycin), linezolid, chloramphenicol
49
Interferes with tRNA complex
clindamycin
50
Inhibit DNA helicase (DNA Gyrase)
Fluroquinolones
51
Inhibit RNA polymerase
Rifampin
52
Length of abx for intra-abdominal infections
4 days after source control (surgery). Not based upon when fever WBC resolves.
53
1st order
1st order – A constant amount of drug eliminated proportional to dose (Concentration dependent) - Tylenol is 1st order
54
half-lives for drug to reach steady state
Takes 5 half-lives for drug to reach steady state
55
Volume of distribution
Volume of distribution – amount of drug in the body divided by amount of drug in plasma. High Vd have higher concentration in extravascular compartment (Fat tissue) compared with intravascular
56
LD50
LD50 – drug level at which death occurs in 50%
57
Drug metabolism
- converts lipophilic compounds to more readily excreted hydrophilic polar water-soluble product
58
HAART therapy in perioperative period
Should be continued in periooperative period; pausing= incresed viral loads and higher complication rates