Hospital Infection Control - UTI + SSI

Hospital Infection Control
Lecture no. 3
Nosocomial Urinary Tract Infections (UTI)
Surgical Site Infections (SSI)


Nosocomial Urinary Tract Infections (UTI)
Nosocomial Urinary Tract Infections
Most common site of NI (40%)
Affects 1/20 (5%) of admissions
80% related to urinary catheters
Associated with 2/3 of cases of nosocomial gram negative bacteremias
Costs to health care system up to $1.8 billion
NosocoNosocomial Urinary Tract Infectionsmial Urinary Tract Infections
25% of hospitalized patients will have a urinary catheter for part of their stay
Incidence of nosocomial UTI is ~5% per catheterized day
Virtually all patients develop bacteriuria by 30 days of catheterization
Of patients who develop bacteriuria, 3% will develop bacteremia
Vast majority of catheter-associated UTIs are silent, but these comprise the largest pool of antibiotic-resistant pathogens in the hospital

PATHOGENESIS
Source of uropathogens
Endogenous- most common
- Catheter insertion
- Retrograde movement up the urethrea (70-80%)
- Patient’s own enteric flora (E.Coli)

Exogenous
- Cross contamination of drainage systems
- May cause clusters of UTI’S
PATHOGENESIS
Major risk factors:
1) Pathogenic bacteria in periurethral area
2) Indwelling urinary catheter
Duration catheterization
Bacterial factors:
properties which favor attachment to uroepithelium, catheters
Growth in biofilm
Bladder trauma decreases local host defenses
ETIOLOGIC AGENTS: catheter associated UTI
TREATMENT
Is this a UTI vs asymptomatic bacteruria?
Use clinical judgement
- urine WBC- pyuria
- bacterial colony counts > 103
- clinical signs/symptoms
No antibiotic treatment for bacteruria
- resolves with catheter removal
7-10 days of therapy for UTI
Empiric therapy typically initiated pending microbiologic results

Prevention of Nosocomial UTIs
Avoid catheter when possible & discontinue ASAP- MOST IMPORTANT
Aseptic insertion by trained HCWs
Maintain closed system of drainage
Ensure dependent drainage
Minimize manipulation of the system

Surgical Site Infections(SSI)
Surgical site infections
325,000/year (3rd most common)
Incisional infections
Infection at surgical site
Within 30 days of surgery
Involves skin, subcutaneous tissue, or muscle above fascia
Accompanied by:
Purulent drainage
Dehiscence of wound
Organism isolated from drainage
Fever, erythema and tenderness at the surgical site
SSI: Superficial
Surgical site infections
Deep surgical wound infection
Occurs beneath incision where operation took place
Within 30 days after surgery if no implant, 1 year if implant
Infection appears to be related to surgery
Occurs at or beneath fascia with:
Purulent drainage
Wound dehiscence
Abscess or evidence of infection by direct exam
Clinical diagnosis

SSI: Deep
Surgical site infections
Risk of infection dependent upon:
Contamination level of wound
Length of time tissues are exposed
Host resistance


Surgical site infections
Clean wound
* Elective, primarily closed, undrained
* Nontraumatic, uninfected
Clean-Contaminated wound
* GI, resp, GU tracts entered in a controlled manner
* Oropharynx, vagina, biliary tract entered
Contaminated wound
* Open, fresh, traumatic wounds
* Gross spillage from GI tract
* Infected urine, bile
Dirty-infected
* These include wounds that have been exposed to fecal material


Surgical site infections
Pathogens associated with SWI
Risk factors
Age (extremes)
Sex
* ?post cardiac surgery
Underlying disease
* Obesity (fat layer < 3 cm 6.2%; >3.5 cm 20%)
* Malnutrition
* Malignancy
* Remote infection

Risk factors
Duration of pre-op hospitalization
* increase in endogenous reservoir
Pre-op hair removal
* Especially if time before surgery > 12 hours
* Shaving>>clipping>depilatories
Duration of operation
*Increased bacterial contamination
* Tissue damage
* Suppression of host defenses
* Personnel fatigue
SWI Prevention
Limit pre-op hospitalization
Stabilize underlying diseases
Avoid hair removal by shaving
Clipping of skin is preferred
Skin decolonization
Chlorhexidine
Intranasal Mupirocin for S.aureus carriers
Impermeable drapes
Maximum sterile barrier precautions
Prophylactic Preoperative Antibiotics
Indicated for clean-contaminated, contaminated operations
High risk or devastating effect of infection
Dirty wounds already infected (therapy)
Administer at appropriate time (tissue levels)
30-60 minutes prior to skin incision