Section 2. Infectious Diseases

Step One: Confirm Infection

General signs and symptoms of infection include:

• Temperature >101°F (>100.4°F in some instances)
• WBC >10 with bands >10%
• Assess for infection-specific signs/symptoms according to algorithms

Step Two: Perform Diagnostic Tests/Workup

• Ensure that cultures are obtained from the site of the infection BEFORE antimicrobial administration
• Gram stain and morphology from culture results may further guide empiric selection
• Assess for severity of infection according to algorithms

Step Three: Start Empiric Therapy

• Review list of likely infectious etiologies according to the algorithms that are largely based on infection site
• Start empiric therapy according to algorithms (base decision on local susceptibility patterns where possible, that is, antibiograms)
• Empiric antimicrobial dosing recommendations can be found in Tables 2.1.2, 2.1.3 and 2.1.4

Step Four: Reevaluate/Monitor Response to Therapy

• Check for resolution of signs and symptoms
• Follow-up culture results/susceptibilities and note MIC when available
• Use Table 2.1.5 to monitor for adverse effects associated with selected empiric therapy and serum concentrations where necessary

Step Five: Streamline/Narrow Antimicrobial Therapy

• Use the most narrow spectrum antimicrobial that is susceptible from culture results
• If MIC results are available, consider selecting an antimicrobial with an MIC well below susceptibility breakpoints found in Table 2.1.6 (NOTE: MICs should NOT be compared across different antimicrobials)

Example

Blood Culture Results: Escherichia coli

S/I/R

MIC

Breakpoint

Ampicillin/sulbactam

R

>32

≤8

←

Resistant

Cefepime

S

2

≤8

←

Compare MIC = 2 to breakpoint ≤8 (“very susceptible”)

Ceftriaxone

I

2

≤1

←

Intermediate

Ciprofloxacin

S

1

≤1

←

Compare MIC = 1 to breakpoint ≤1 (“susceptible”)