3 - Principles of using Anti-Infectives

Question 1

5D’s
AntiBiotic Therapy

Answer 1

Diagnosis

Drug - Duration - Dose

De-escalation

Question 2

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#1

Answer 2

Is an anti-infective agent INDICATED on the basis of clinical findings?

LOCALIZED Clinical Signs of Infxn:
Pain & Inflammation / Purulent Discharge / Sputum + Cough
Diarrhea / Dysuria - Frequency - Ugency / Headache - Stiff Neck

Systemic Clinical Signs of Infxn:
Fever / Chills / Malaise
Tachycardia / Tachypnea / Hypotension / Mental status changes

Question 3

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#2

Answer 3

Have the appropriate CLINICAL SPECIMENS been
obtained/examined/cutured?

Radiographic Signs
Chest X-ray / Bone-MRI / Head CT-MRI

Nonspecific Lab SIgns
↑WBC/ ↑Neutrophil %–> ↑Immature nutrophils in WBC diff
= SHIFT TO THE LEFT
↑ESR & CRP
↑Procalcitonin & ↑ Lactin
Hypoxemia

Question 4

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#3

Answer 4

What ORGANISM(S) are most likely to be causing the infxn

Educated Guess –> Definitive Therapy (once ID)

Focal Findings

Age / Severity / Prior Cultures

Epidemiologic Features
Community vs Hospital // Prior AB use

Question 5

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#4

Answer 5

If multiple anti-infectives are available which is BEST for a given patient?

Is there an obvious drug of choice?

Allergies? / Side Effects?

Penetration or pH @ site?

BacteriCIDAL vs bacterioSTATIC?

COST

Narrow vs Broad-spectrum

Question 6

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#5

Answer 6

Is an antibiotic combo appropriate?

Disadvantages of COMBO AB’s
↑risk of drug sensitivities or toxicity

↑risk of colonization w/ resistant organism

↑Costs

Possibility of antagonism / False security

Question 7

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#6

Answer 7

Are there special considerations related specifically to host factors?

Genetics / Pregnancy / Lactation

Renal + Hepatic Fxn

Question 8

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#7

Answer 8

What is the BEST ROUTE of ADMIN?

IV FOR SERIOUS INFECTIONS

Question 9

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#8

Answer 9

What is the Appropriate DOSE?

EMPIRIC THERAPY:
Maximum Efficacy & Minimal Toxicity
and
REDUCE AntiMicrobial Resistance

Antibiotic PK&PD Parameters
MIC Distribution

Question 10

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#9

Answer 10

Will initial therapy need modification after culture data are returned?
“De-escalation with Q9&Q10”

Question 11

Series of 10 Questions Routinely Addressed Before
Selecting Antibiotic Therapy

#10

Answer 11

What is the optimal duration of treatment, and is development of resistance during prolonged therapy likely to occur?

“De-Escalation”

Question 12

Left Shift

Answer 12

Possible Sign of Infection

↑Immature Neutrphils (bands or stabs)
in the WBC Differential

Question 13

Non-Specific Lab Signs of Infections

Answer 13

↑WBC Count
Peripheral or Site of Infxn

↑Neutrophil % + ↑Immature Neutrophils = Left Shift

↑ESR & ↑CRP

↑ProCalcitonin & ↑Lactate

Hypoxemia
(Lung Infxn)

Question 14

Flow Diagram
DE-ESCALATION APPROACH TO AB THERAPY

Answer 14

Serious HA Infxn Suspected
Obtain cultures / stains

Begin empirical therapy & Factor for MDR pathogens / Susceptibility
Follow clinical parameters: Temp / WBC / XRAY / Organ Fxn

Evaluate for Response @ 48-72 Hours
De-escalate based on the results of data

• *IMPROVEMENT**
• *Narrow Spectrum –> reassess need for therapy after 5-8 days**

NO IMPROVEMENT
Reassess patient on: Resistance / Complications / Non-infxn / Penetration

Question 15

General Flow chart for Infectious Diseases

Answer 15