Infection Symptoms and Antibiotic Quiz

Introduction to Clinical Infectious Disease

• Dr. Joshua Garcia, PharmD, is the Associate Professor of Pharmacy Practice at Marshall B. Ketchum University's College of Pharmacy. His email address is [email protected].

Objectives

• Differentiate between the different steps of the General Approach to a Patient with Infectious Disease.
• Identify general signs, symptoms, and characteristics of an infected patient.
• Describe the steps in the microorganism identification process.
• Define antimicrobial stewardship.
• List the consequences of inappropriate and/or unnecessary antibiotic use.

Lecture Outline

• Introduction to Clinical Infections
• Infection Definition
• Signs and Symptoms
• General Approach to a Patient with Infectious Diseases
• Primary Prophylaxis
• Empiric Therapy
• Narrowed Therapy
• Definitive Therapy
• Secondary Prophylaxis

Introduction to Clinical Infections

• Infectious Disease is a significant health concern worldwide.
• Leading causes of death globally include heart disease, stroke, COPD, lower respiratory infections, cancer, diabetes, malaria, tuberculosis, road injury, preterm birth complications, & kidney diseases.

What is an Infection?

• A disease caused by a pathogenic organism overcoming a host's defense system and invading the body.
• Requirements for Infection:
  • Entry into host
  • Establishment in host
  • Defeat/avoiding host defenses
  • Damage to host
  • Exit and transmission to next host
• Infections can range from minor (self-limiting) harm to death in humans.

The Body's Defenses

• Constitutive Defenses (Non-specific):
  • Physical and chemical barriers to infection
  • Increasing inflammatory response
  • Complement pathway activation
  • Phagocytosis (neutrophils)
• Induced Defenses (Specific to Organism):
  • T-lymphocyte cells
  • B-cells

Infection Immune System Relationship

• At different stages, levels of pathogens versus immune cells are different.
  • Infection is prevented when the level of immune cells is higher than pathogen cells.
  • Patient is infected when pathogen cell level is higher than immune cells level.
  • If antibiotics are needed, the goal is to restore a level of immune cells higher than pathogen levels.

What Does an Infection Look Like?

• Tachycardia (heart rate >100 bpm)
• Tachypnea (breathing rate >20 bpm)
• Temperature > 38°C (~100°F)
• Hypotension (systolic blood pressure ≤ 90 mmHg)
• Symptoms specific to certain infections (e.g., SOB in pneumonia, dysuria in UTIs).
• Not all infected patients exhibit all or even any generalized symptoms.

Abnormal Labs Associated with Infections

• Leukocytosis (WBC >10,000 cells/mcL): most common lab for evaluating infection
• Bandemia (Increase in immature white blood cells)
• ESR (Erythrocyte Sedimentation Rate): Marker of inflammation
• CRP (C-Reactive Protein): Marker of inflammation (bacterial infection)
• Procalcitonin: Response to bacterial infection (not viral or fungal infections).
• Microbiological cultures from specific sites

Distinguishing Infectious vs. Non-Infectious Etiology

• Causes of non-infectious diseases can include CHF exacerbation, asthma, hypothyroidism, dementia, or medications.
• Diagnosing infections requires a thorough/systematic approach using both microbiologic confirmation and clinical judgment.

General Approach to a Patient with Infectious Disease

• Infection suspected -> Cultures obtained -> Preliminary cultures return -> Final cultures and susceptibilities return -> Cure -> Secondary Prophylaxis.
• Steps in the process are empiric therapy -> narrowed therapy -> definitive therapy
• Initial approach is empiric therapy - broad spectrum antibiotics.
• Second step is narrowing the treatment approach to specific pathogen identification (culture/sensitivity) and targeting treatment.

Breadth of Coverage

• Broad-spectrum antibiotic: effective against many organisms
• Problematic due to higher antibiotic resistance, potentially severe adverse effects, and bacterial superinfection.
• Narrow-spectrum antibiotic: only effective against a few organisms
• Useful when the causal organism is known or suspected

Breadth of Coverage (Gram Positive/Negative)

• Specific examples of bacteria and the antibiotics that affect them.

Consequences of "Big Gun" Antibiotic Use

• Antibiotic resistance
• Super infection
• Various toxicities
• Allergic reactions

Empiric Therapy

• Use of broad-spectrum antimicrobial therapy when little is known about the causative organism
• High chance of obtaining proper organism but often leads to adverse effects.

Empiric Therapy: Breadth vs. Depth of Coverage

• Breadth of coverage: number of different organisms an antibiotic covers.
• Depth of coverage: chance an antibiotic will cover a particular organism (based on variability of resistance).

How to Determine Depth of Coverage

• Varies between hospitals and is determined by an antibiogram.

Antibiograms

• Report the effectiveness of antibiotics in a hospital.

Depth Comparison Rule of Thumb

• Charts showing the relative depth and efficacy of different classes of antibiotics.

Thinking About Spectrum of Activity for Empiric Therapy

• Tables/charts demonstrating the appropriate use of narrow spectrum drugs for various infections.

Common Empiric Regimens

• Several examples of treatment regimens based on different patient presentations.

Narrowed Therapy

• Use of narrow-spectrum antibiotics when some information about the causative organism is available.

Microorganism Detection Overview

• Microorganism detection overview including steps from sample collection to gram staining, to inoculation, incubation and analysis.

Example of Narrowed Therapy

• Tables with examples of treatment options depending on the Gram type (+ or -).

Definitive Therapy

• Use of the narrowest spectrum antibiotic after specific identification of the organism
• Usually based on cultures and sensitivity results.

Example of Definitive Therapy

• Tables with examples of treatment options based on specific bacterial/pathogen isolates.

Microorganism Detection Overview

• Further, detailed method overview including gram staining, broth dilution, and other methods of micro organism identification.

What is an MIC?

• MIC = Minimum Inhibitory Concentration
• The lowest amount of drug needed to inhibit growth of an organism.
• Measured via broth dilution assays to determine the MIC for a given antibiotic
• MIC values are used in treatment selection, based on the MIC to organism, to determine if the antibiotic will be effective.

Determining the MIC

• Detailed method via broth dilution for determining of MIC.

MIC Reporting Example

• Example of MIC values for various antibiotics

MIC Interpretation

• Importance of appropriate interpretation of MIC values, rather than just finding the “lowest” MIC.

Rapid Diagnostic Tests (RDTs)

• Aids in the quicker identification and detection of pathogens to prevent unnecessary or inappropriate antimicrobial use.
• Includes MALDI-TOF, BioFire, Verigene, and Next Gen Sequencing.

General Approach to Patient with Infectious Disease

• Primary Prophylaxis: use of antimicrobial therapy to prevent infections before they occur.
• Examples include antibiotics given before surgery, to immunocompromised patients (cancer patients, HIV/AIDS, or transplant)

Secondary Prophylaxis

• Use of antimicrobial therapy after a patient has been treated for an infection.
• Examples may include antibiotics for recurring UTI or spontaneous bacterial peritonitis (SBP).

Antimicrobial Stewardship

• Strategy for appropriate use of antimicrobial medications to improve patient outcomes, reduce antibiotic-resistance, and decrease costs.

Questions from Lecture

• Questions regarding the material presented during the lecture.

Clinical PK/PD of Cell Wall Inhibitors

• Objectives, lecture outline, and a review of Beta-lactams and glycopeptides.

Let's Take a Second to Review

• Review of different classes of cell-wall inhibitors

Concentration vs Time Killing

• The graph depicts the relationship between drug concentration and time in the blood.
• Key parts of the graph are the peak, trough, and area under the curve.

Concentration Dependent Killing

• Graph showing the relationship between drug concentration over time and ability to kill target bacteria
• Peak:MIC ratio is an important consideration for selecting and dosing drugs

Time Dependent Killing

• Graph showing the relationship between the duration and concentration of the antibiotic to time.

AUC Dependent Killing

• Graph showing the relationship between the area under the curve and the MIC value of the target bacteria.

Bacteristatic vs Bactericidal

• Clarification of the antimicrobial agents that are bacteristatic (inhibits growth) vs. those that are bactericidal (kill outright the bacteria)
• Different antibiotic classes have specific properties

Periodic Table of Antibiotics

• Categorization of antibiotics by mechanism of action into (antimicrobial groups) cell-wall, protein, DNA inhibition or other methods of action

Clinical Case #1, #2

• Case studies presenting specific patient factors and potential challenges to therapy.
• Questions regarding the appropriate antibiotic selection, therapy, and duration for patients described in the case studies.

Clinical PK/PD of Protein Synthesis Inhibitors

• Study of aminoglycosides (characteristics, dosing, monitoring, etc) and additional information.

Biliary Tract Infections

• Pathophysiology, microbiology, clinical presentation, and diagnosis of biliary infections.
• Classification of the infections (Mild to Moderate Risk, High Risk and Healthcare Associated)
• Treatment options: supportive care and surgical management
• Empiric/Definitive antibiotic therapy options for low, and high risk infections.

Surgical Site Infection (SSI) Prophylaxis

• Overview of pathogens, preoperative, intraoperative, and postoperative prophylactic measures to prevent SSIs
• Description of modifiable and nonmodifiable risk factors for SSIs.

Lower Respiratory Tract Infections (CAP/HAP/VAP & COVID-19)

• Differentiating between community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP); and COVID-19.
• Identifying signs, symptoms, risk factors, and complications associated with these infections.
• Creating an appropriate antimicrobial treatment regimen for hospitalized patients with CAP, HAP, or VAP; and COVID-19.
• Discussing the importance of obtaining appropriate specimens (e.g., cultures) to ensure good diagnostics.

Cardiovascular System Issues

• Overview of infective endocarditis (characteristics, epidemiology), Microbiology identification methods, diagnosis and evaluation, treatment, and prevention procedures.

Test your knowledge on the symptoms of infections and the use of antibiotics. This quiz covers key concepts such as tachypnea, bandemia, and the distinction between broad-spectrum and narrow-spectrum antibiotics. Ideal for medical students or healthcare professionals looking to reinforce their understanding.