IP: Infectious Disease Exam 2

Unmodifiable preoperative patient-related risk factors for infection

- age

- history of radiation

- history of skin and soft tissue infections

Modifiable preoperative patient-related risk factors for infection and associated recommendations

- glucose control - control serum glucose in all patients

- obesity - increase prophylactic antibiotic dose

- smoking cessation - encourage within 30 days

- hypoalbuminemia

- S. aureus nasal colonization - decolonize with nasal mupirocin, chlorhexidine, or povidone-iodine prior to surgery

Hair removal recommendations for surgical patient preparation

- do not remove hair unless it will interfere with operation

- remove outside the OR using clippers

- do NOT use razors

Preoperative infection recommendations for surgical patient preparation

- identify and treat infections remote from surgical site

- do not routinely test or treat asymptomatic bacteriuria except in urological procedures

Surgical scrub recommendation for surgical team to minimize risk factors

use appropriate antiseptic and scrub for 2-5 minutes

Surgeon skill/technique recommendation for surgical team to minimize risk factors

Handle tissue gently

Remove devitalized tissue

Appropriate gloving recommendation for surgical team to minimize risk factors

Team should be double-gloved

Change gloves if perforated

Asepsis recommendation for surgical team to minimize risk factors

Follow standard operating room aseptic principles

Operative time recommendation for surgical team to minimize risk factors

Minimize duration when possible without compromising technique

Patient skin preparation recommendation to minimize infection risk in surgery

Clean incision site

Use alcohol-containing prep unless contraindicated

Antimicrobial prophylaxis recommendation to minimize infection risk in surgery

Give only when indicated

Choose agents based on procedure/pathogens

Give within 1 hour of incision

Stop after wound closure

Blood transfusion recommendation to minimize infection risk in surgery

Minimize transfusion when possible

Reduce blood loss

Blood transfusions increase SSI risk

Clean wound criteria and associated need for antibiotics

- no acute inflammation

- no entry into respiratory, alimentary, genital, or urinary tract

- elective case

- no technique break

*Antibiotics not indicated unless high-risk procedure*

Clean-contaminated wound criteria and associated need for antibiotics

- controlled entry into respiratory, alimentary, genital, or urinary tract without major contamination

- clean procedures with minor technique breaks

- emergent or major technique breaks

*Prophylactic antibiotics indicated*

Contaminated wound criteria and associated need for antibiotics

- acute inflammation present

- major technique break

- gross spillage from GI tract

- fresh open wounds

*Prophylactic antibiotics indicated*

Dirty wound criteria and associated need for antibiotics

- obvious preexisting infection or perforated viscera

- necrotic or devitalized tissue

*Therapeutic antibiotics required*

Major pathogens causing surgical wound infections

Staph. aureus

Coagulase-negative staphylococci

Enterococci

E. coli

Psedomonas aeruginosa

Enerobacter species

(and more)

General recommendations for pre-operative antibiotics

- delivery to site of infection before incision

- maintain bactericidal concentration for surgical duration

- antibiotic administration should begin within 60 minutes of initial incision and before tourniquet inflation

- higher doses based on weight

- drug selection based on surgery and likely organisms

_________ requires 60 minutes to infuse and administration duration should be considered when determining start time for surgical prophylaxis

Metronidazole

For surgical prophylaxis, ____________ and _____________ administration should begin within 120 min due to longer half-life

Vancomycin and Fluoroquinolone

Two criteria for surgical prophylaxis antibiotic redosing

1. give another dose when surgery is longer than two half-lives of the antibiotic (ex. 4 hours for Cefazolin)

2. give another dose when intraoperative blood loss >1.5L

Antibiotic duration for surgical prophylaxis should be less than ___ hours

24 hours (unless specific procedure requires longer)

Which class of antibiotics are preferred for surgical prophylaxis?

cephalosporins

Antimicrobial Stewardship principles for surgical prophylaxis

- use narrowest agent possible

- cephalosporins are preferred

- use Vancomycin only when necessary

- decolonize patients with anti-staphylococcal agents for orthopedic and cardiothoracic procedures

Anti-staphylococcal agents that may be used to decolonize patients prior to orthopedic and cardiothoracic procedures

Mupirocin (Bactoban) ointment intranasal BID x5days

Chlorhexidine bathing daily

Non-pharmacological interventions to help prevent infections in surgery

- maintain normothermia

- supplemental oxygen

- perioperative glucose control

Difference between uncomplicated and complicated UTI

uncomplicated = limited to the bladder

complicated = infection beyond the bladder

Cystitis is classified as which type of UTI

uncomplicated UTI

Classifications of complicated UTI

- catheter associated (CAUTI)

- Pyelonephritis (infection of the kindey)

- Febrile or bacteremic UTI

Most common route of UTI pathophysiology

ascending - enteric bowel flora gets to bladder from the urethra

Major species causing UTI

E. coli

Staph. saprophyticus

(less so Klebsiella pneumoniae, Proteus species, Enterococcus species, and Pseudomonas aeruginosa)

S/sx of uncomplicated UTI/Cystitis

dysuria

urgency

frequency

nocturia

suprapubic heaviness

gross hematuria

S/sx of UTI commonly seen in elderly patients

altered mental status (rule out other causes)

change in eating habits

GI upset

Factors assessed for in suspected UTI urinalysis

Pyuria (WBC >10)

Leukocyte esterase presence

Nitrite positive urine

Bacteriuria

RBC's to see if traumatic cath/collection

Squamous cells to assess clean catch

______ reduce nitrates to nitrites and will thus cause nitrite positive urine on urinalysis

Enterobacterales

_________ is a surrogate marker for pyuria on urinalysis

Leukocyte esterase

___________ is non-specific but signifies presence of inflammation (not necessarily infection) on urinalysis

pyuria (WBC >10)

Describe how Pyuria is used in urinalysis

- NOT diagnostic

- high negative predictive value but poor positive predictive value

Describe diagnosis of UTIs

- quantitative urine culture + symptoms

- usually >100,000 bacteria/mL indicates infection (may have less and still be symptomatic)

When should cultures NOT be performed in suspected UTI?

uncomplicated cystitis

When should cultures be performed in suspected UTI?

- complicated UTI

- hx of multi-drug resistance

- recurrence or relapse

__________ should NOT be used for UTI treatment since it does not concentrate in the urine

Moxifloxacin

Therapeutic options for uncomplicated UTI/Cystitis

- Nitrofurantoin x5 days

- Bactrim x3 days

- Fosfomycin trometamol single dose

- Pivmecillinam BID x3-7 days

- Cephalexn x5-7 days

- Cefpodoxime x5-7 days

- Ciprofloxacin or Levofloxacin x3 days

Nitrofurantoin should be avoided in CrCl <______ ml/min

30

Nitrofurantoin duration of tx for Cystitis

5 days

Nitrofurantoin and Fosfomycin should be avoided if __________ is suspected

pyelonephritis

Bactrim duration of tx for Cystitis

3 days

Bactrim should be avoided if used within the previous ___ months for UTI due to increased risk for resistance

3

Which Cystitis tx option is best for E. coli?

Fosfomycin trometamol 3g single dose

Pivmecillinam duration of therapy for Cystitis

3-7 days

Duration of Cephalexin or Cefpodoxime treatment for Cystitis

5-7 days

Which beta-lactams should be avoided empirically for Cystitis due to high prevalence of antimicrobial resistance?

Amoxicillin

Ampicillin

Amoxicillin/clavulanate

Duration of Ciprofloxacin/Levofloxacin treatment for Cystitis

3 days

Describe use of Fluoroquinolones for cystitis

reserve use for patients with no alternative treatment options due to risk of disabling and potentially serious adverse reactions (last line)

S/sx of pyelonephritis

flank pain

CVA tenderness

fever

nausea

vomiting

malaise

S/sx of CAUTI

(indwelling, urethral, suprapubic, or intermittent catheterization)

flank pain

fever

leukocytosis

will NOT have lower urinary tract symptoms due to catheter

Species commonly causing CAUTI

E. coli

Klebsiella pneumoniae

Proteus species

Enterobacter species

Enterococcus species

Pseudomonas aeruginosa

Principles for catheterization in CAUTI

- avoid catheters if possible and remove as soon as possible due to rapid colonization

- both symptomatic and asymptomatic catheters should be removed if possible

- if catheter cannot be d/c and is >2 weeks old, it should be changed and urine culture should be obtained from newly placed catheter

Which patients with CAUTI require antibiotic therapy?

only symptomatic patients

Antibiogram threshold for patients with complicated UTI and sepsis + shock

>90% susceptible

Antibiogram threshold for patients with complicated UTI and sepsis without shock

>80% susceptible

Preferred empiric antibiotics for complicated UTI in patients with sepsis with or without shock

3rd or 4th generation cephalosporins

Carbapenems

Piperacillin/tazobactam

Fluoroquinolones

Preferred empiric antibiotics for complicated UTI in patients without sepsis and IV therapy is preferred

3rd or 4th generation cephalosporins

Piperacillin/Tazobactam

Fluoroquinolones

Preferred empiric antibiotics for complicated UTI in patients without sepsis and oral therapy is preferred

Fluoroquinolones or Bactrim

Fluoroquinolone duration of therapy in complicated UTI

5-7 days (5 days if levofloxacin 750mg)

Non-fluoroquinolone duration of therapy in complicated UTI

7 days

Criteria for IV to Oral switch in complicated UTI

Clinically improving > assess for oral options > switch to oral agent > treat for 7 days total

Which 3rd generation cephalosporin is NOT a good oral agent for complicated UTI due to poor oral absorption and low urinary excretion?

Cefdinir

Treatment options for Candida UTIs + symptoms

Fluconazole

- if Fluconazole resistant used Amphotericin B or Flucytosine

Define recurrent UTIs

>2 UTIs in 6 months OR >3 UTIs in 12 months (at least one should be culture proven)

Risk factors for recurrent UTIs

premenopausal - sexual activity and spermicide-containing contraceptives

postmenopausal - incontinence, hx of UTI, residual urine after voiding, nonsecretor status, vulvovaginal atrophy, change in urinary microbiome

Behavioral strategies for prevention of recurrent UTIs

Hydration and/or pelvic floor physical therapy if incomplete voiding

Non-antimicrobial strategies for prevention of recurrent UTIs

- methenamine

- cranberry

- d-Mannose

- vaginal estrogen if postmenopausal

Antibiotic prophylaxis strategies for prevention of recurrent UTIs

- post-coital antibiotics if sexual activity is a trigger

- low doe continuous antibiotics

Define asymptomatic bacteriuira (ASB)

presence of 1 or more species of bacteria growing in the urine at a specified quantitative counts (>100,000 bacteria/mL) irrespective of pyuria, in the absence of signs or symptoms attributable to UTI

T/F: most people should not be screened or treated for ASB

true

When is ASB testing recommended in pregnancy?

initial prenatal visit and 28 weeks gestation

Potential results of untreated ASB in pregnancy

prematurity

low birth weight

stillbirth

Duration of antimicrobial treatment for ASB in pregnancy

4-7 days

Antibiotics that may be used (and when) for UTIs in pregnancy

- beta lactams

- nitrofurantoin in early pregnancy (not at term)

- Bactrim in 2nd trimester only

Who should be treated for ASB?

pregnant patients and those undergoing endoscopic urologic procedures associated with mucosal trauma

Define prostatitis

inflammation of prostate gland and surrounding tissue as a result of infection

S/sx of acute prostatitis

sudden onset fever

chills

malaise

myalgias

perineal, rectal, or sacrococcygeal tenderness

urinery symptoms (frequency, urgency, dysuria, nocturia, retention)

S/sx of chronic prostatitis

urinarting difficulty

low back pain

suprapubic pressure

perineal pressure

How is chronic prostatitis typically diagnosed?

based on recurring infections with the same organism from incomplete eradication of bacteria from prostate gland

Potential pathogenesis of prostatitis

- ascending and descending routes similar to UTI

- reflux of infected urine into prostate gland

- sexual intercourse may contribute

- indwelling catheters, urethral instrumentation, and transurethral prostatectomy are known to cause prostatitis in patients with infected urine

- alteration of physiologic factors

Most common pathogens causing prostatitis

gram-negative enterobacterales species (bacterial flora)

- E. coli

- K. pneumoniae

- Proteus mirabilis

Chronic prostatitis is usuallly caused by _________

E. coli

Oral antimicrobial options for prostatitis

- Ciprofloxacin or Levofloxacin

- Bactrim

- Possibly cephalosporins or beta lactam-beta-lactamase inhibitors

IV antimicrobial options for prostatitis

- Piperacillin/tazobactam

- Ceftriazone

- Fluoroquinolones

Duration of acute prostatitis treatment

2-4 weeks

Duration of chronic prostatitis treatment

4-6 weeks

Define resistance

the natural or acquired capacity of an organism to survive the effects of an antimicrobial agent

__________ is the single most important factor leading to antimicrobial resistance

The use of antimicrobials

Define MIC

lowest drug concentration at which a drug inhibits growht of a bug

Define MBC

lowest drug concentration that results in 1000x reduction in bacterial density at 24 hours

Which breakpoint classification is given when the bug should respond to therapy using recommended drug doses?

susceptible

Which breakpoint classification is given when the bug should respond to therapy but only at aggressive defined dosing ranges?

susceptible dose dependent

Which breakpoint classification is given when the MIC approaches and/or exceeds the threshold for normal dosing, but clinical resopnse is possible with higher doses?

intermediate

Which breakpoint classification is given when the bug should NOT respond to therapy?

resistant