HAI & Antibiotics (Exam II) Flashcards
What are sources of hospital-acquired infections?
- CVL sepsis
- UTI 13%
- SSI 22%
- HAP 22%
- VAP
- C-diff 12%
What contaminated environments increase susceptibility to HAI’s?
- Inguinal
- Perineal
- Axilla
What bacteria are your skin flora?
Coag neg staphylococci
What labs can be useful for evaluation of HAI’s?
- Lactate
- PT
- Bun/Ct
- WBCs
- Blood glucose
- Cultures
Surgical site infections typically occur within ___ days of surgery.
30
What are the categories for surgical site infection?
- Superficial = skin & SC
- Deep = fascia & muscle
- Organ/Space
What are the three most common types of bacteria associated with surgical site infections?
- Staphylococcus
- Streptococcus
- Pseudomonas
How would a wound that is not inflamed or contaminated and does not involve internal organs be categorized?
Clean
How would a wound that has no outward signs of infection but does involve internal organs be categorized?
Clean-Contaminated
How would a wound that involves internal organ infection along with spillage of contents into surrounding tissue be categorized?
Contaminated
What is an example of contaminated SSI?
Ruptured appendix
How is a Dirty SSI defined?
Known infection at the surgical site at the time of the surgery.
What are risks factors for SSI?
- > 2hr surgery
- Comorbidities (smoker, DM, cancer, obese, etc)
- Elderly
- Emergency surgery
- Abdominal surgery
Potentially ___% of SSI’s are preventable.
50%
What is a category 1A recommendation?
1A = Strongly recommended; moderate to high quality of evidence
What is a category 1B recommendation?
1B = Strongly recommended; low quality evidence
What is a category 1C recommendation?
1C = Strong recommendation based on state/federal regulation
What is a category II recommendation?
Weak recommendation
What exclusions were there to the Guideline for Prevention of SSI’s?
- SSI not a reported outcome
- All patients w/ “dirty procedures”
- No dental or oral health procedures
- Procedure did not have primary closure
- Study included wound protectors post-incision
What are the recommendations for parenteral antibiotics?
1B - Administer only when indicated
1B - Time so that agent is active on tissue incision
What are the recommendations for non-parenteral antibiotics?
1B - no antibiotic ointment on incision
Dry incisions are better.
What recommendations are there for antibiotic irrigation and prosthetic soaking in antibiotic solution?
No recommendations on prosthetic soaking in abx solution or abx irrigation
What are the 1A recommendation levels for glycemic control?
- Perioperative control of glucose
- Target glucose < 200 mg/dL
What is the recommendation level for A1C targets?
No recommendation for A1C target
Just acute control of BG.
Maintaining perioperative normothermia is a ___ recommendation.
1A
What is the 1A recommendation for oxygenation in GETA patients?
↑ FiO₂ w/ GETA patients w/ normal pulmonary function.
Recommendation is losing credibility as a way to prevent SSI’s.
What are the recommendations for antiseptic prophylaxis?
1A - Intraoperative skin prep w/ alcohol-based antiseptic.
1B - Shower or bathe w/ soap/antiseptic the night before surgery.
II - Consider intraoperative Iodine irrigation.
What is the recommendation for blood transfusion?
1B - Do not withhold necessary blood transfusions as a means to prevent SSI.
Should systemic corticosteroids be utilized in a patient with joint arthroplasty?
Uncertain. Infection is most common indication for TKA revision however.
What does MIC stand for?
Minimum Inhibitory Concentration
What are the 6 general principles of preoperative antibiotic prophylaxis?
- Should be active against common SSI pathogens
- Proven efficacy by clinical trials
- MIC must be achieved
- Shortest possible effective course
- New ABX reserved for resistant infections
- If possible, use oldest/cheapest ABX
ABX should be initiated within ____ hour of incision.
1 hour
_________ and _________ can be initiated within 2 hours of incision.
Vancomycin and Fluoroquinolones (like Cipro)
Can antibiotics be held for cultures?
yes
ABX must be completely infused prior to use of a __________.
Tourniquet
Re-dosing of antibiotics is permissible after what conditions?
- 2 ABX half-lives
- Excessive blood loss
- Cardiac bypass
- Prolonged procedures (usually 2-4 hours in OR)
What drugs are β-lactam based?
- Penicillins
- Cephalosporins
- Carbapenems
What are the 5 major common surgical antibiotics?
- β-lactams
- Vancomycin
- Aminoglycosides (gentamycin)
- Fluoroquinolones (cipro)
- Metronidazole (flagyl)
How do Penicillin β-lactam antibiotics work?
Inhibition of bacterial cell wall synthesis
Resistance to Penicillin β-lactam antibiotics is based on what?
β-lactamase enzyme on outer surface of cytoplasmic membrane
Penicillin β-lactams are the drug of choice for what pathogens?
Gram + Bacterium (Cocci)
- Streptococci
- Meningococci
- Pneumococci
β-lactams are good for which HAI’s?
skin, catheter, and upper respiratory infections
What four examples of penicillin based antibiotics were given?
- Penicillin G
- Methicillin
- Nafcillin
- Amoxicillin
What are the common adverse reactions to penicillin β-lactams?
- Hypersensitivity (includes anaphylaxis)
- GI upset
- Vaginal Candidiasis
_________ β-lactams are more stable against β-lactamase.
Cephalosporin
Cephalosporin β-lactam antibiotics are the drug of choice for what?
- Surgical prophylaxis
- PCN allergy patients (except true anaphylaxis)
What drug was noted for treatment of gonorrhea?
Ceftriaxone
What cephalosporins do not penetrate the blood brain barrier?
Generation 1: Cefazolin
Generation 2: Cefuroxime, Cefoxitin, Cefotetan
What generation of cephalosporins penetrate the blood brain barrier well?
Generation 4: Cefepime
Most resistant to β-lactamase.
Reserved for multi-resistant organisms.
What cephalosporins are third generation? How well do they cross the BBB?
Cefotaxime
Ceftriaxone
Ceftazidime
Some cross the BBB fairly well.
What drugs should be used if true anaphylaxis to penicillin exists?
Vancomycin or clindamycin
What are the adverse effects are associated with cephalosporins?
- Rashes, fever, nephritis, anaphylaxis
- Vitamin K production deficit
What drugs are a common cause of colitis?
3rd generation cephalosporins
Carbapenem β-lactams have good activity against _______ __ _______ and ________.
Gram - rods (Pseudomonas Aeruginosa) and enterobacter
What β-lactam drug class has the broadest spectrum of activity and can inhibit the β-lactamase enzyme?
Carbapenems
What type of infections are carbapenems saved for?
Intra-abdominal, resistant UTIs, and pneumonia
What examples of carbapenems were given?
- Ertapenem
- Meropenem
- Imipenem
IM formulations of carbapenems contain _______.
Lidocaine
Consider LA allergies prior to IM administration.
Carbapenems can decrease what medication by up to 90%?
What can this precipitate?
Valproic Acid (Depakote); and can precipitate seizures
How does vancomycin work?
Inhibition of cell wall synthesis
Vancomycin is active against _____ bacteria but is too large to penetrate ______ bacteria.
Active against gram + ; too large for gram - bacteria
Vancomycin is most useful against what infections?
Blood stream MRSA
MRSA endocarditis
What are the most common adverse reactions to vancomycin?
- Phlebitis at site
- Chills, fever
- Nephrotoxicity
- “Red man” syndrome
How do Aminoglycosides work?
Inhibition of ribosomal proteins and cause mRNA misreading
Aminoglycosides have a _________ post-antibiotic effect.
prolonged
Aminoglycosides are _______ w/ β lactams or vancomycin.
Synergistic
Especially useful for enterococcal endocarditis.
What are the adverse reactions associated with gentamycin?
- Ototoxicity
- Nephrotoxicity
- Curare-like affect
Explain the curare-like effect of gentamycin (aminoglycoside).
Gentamycin can interfere with ACh receptors and potentiate effects of NMB drugs.
What is the treatment for curare-like effects from gentamycin?
Ca⁺⁺
How do fluoroquinolones work?
Inhibit bacterial DNA synthesis
Fluoroquinolones are best used for what type of bacteria?
Gram - organisms:
- UTI
- Bacterial diarrhea
- Bone/joint infections
What examples are there of fluoroquinolones?
- Ciprofloxacin
- Levofloxacin
What are the adverse reactions for fluoroquinolones?
- N/V/D
- QT interval prolongation
- Cartilage damage / Tendon rupture
What three factors will exacerbate cartilage damage and tendon rupture associated with fluoroquinolones?
- Renal insufficiency
- Concurrent steroids
- Advanced age
What type of antibiotic is metronidazole?
Antiprotozoal / Anaerobic antibacterial
How does Metronidazole work?
Forms toxic byproducts that destabilize bacterial DNA.
What is metronidazole (flagyl) indicated for?
- Intra-abdominal infections
- Vaginitis
- C-diff
What drug should Flagyl not be combined with?
EtOH
Disulfiram effect induces hangover-like s/s
What are the adverse reactions associated with metronidazole?
- Nausea
- Peripheral neuropathy (w/ prolonged use)
- Disulfiram-like effect
What is (essentially) the first line antibiotic for essentially all surgical prophylaxis?
Cefazolin
What is the most common alternative to cefazolin for surgical prophylaxis?
Clindamycin (or vancomycin)
What drug(s) increases the likelihood of nephrotoxicity when paired with aminoglycosides?
Loop Diuretics
