Microbiology, Infections, and Antibiotic Therapy

Microbiology, Infections, and Antibiotic Therapy
Presentation by: Elizabeth J. Rosen, MD
Francis B. Quinn, MD


Basic Bacteriology
Shape
Arrangement
Gram Staining
Cell Wall Characteristics

* Gram Positive
* Gram Negative

Bacterial Growth

* Binary Fission = Exponential Growth
* Four Phases of Growth

Normal Bacterial Flora
Host Defense Mechanisms

* Nonspecific Immunity
o barriers
o inflammatory response
* Specific Immunity
o Passive
o Active
+ humoral
+ cell-mediated

Clinical Microbiology

* Gram Positive Cocci
* Gram Positive Bacilli
* Gram Negative Cocci
* Gram Negative Bacilli
* Anaerobes
* Spirochetes
* Mycobacteria

Gram Positive Cocci

* Staphylococcus
* Streptococcus

Staphylococcus

* S. aureus, S. epidermidis, S. saprophyticus
* S. aureus

Streptococcus

* S. viridans
o oral flora
o infective endocarditis
S. pyogenes

* Group A, beta hemolytic strep
* pharyngitis, cellulitis
* rheumatic fever
+ fever
+ migrating polyarthritis
+ carditis
+ immunologic cross reactivity
* acute glomerulonephritis
+ edema, hypertension, hematuria
+ antigen-antibody complex deposition
S. pneumoniae

Gram Negative Cocci

* Neisseria
o meningitidis
o gonorrhea
* Moraxella catarrhalis

Gram Positive Bacilli

* Clostridium
* Bacillus
* Corynebacterium
* Listeria
* Actinomyces
* Nocardia

C. tetani
C. botulinum

* Descending weakness-->paralysis
* diplopia, dysphagia-->respiratory failure

C. perfringens
C. diphtheriae

* Fever, pharyngitis, cervical LAD
* thick, gray, adherent membrane
* sequelae-->airway obstruction, myocarditis
* colony morphology
L. monocytogenes
Actinomyces

* Part of normal oral cavity flora
* 50% of infections occur in face & neck
* forms abscesses with sulfur granules
* draining sinus tracts

Nocardia
Gram Negative Bacilli

* Facultative Anaerobes
o Respiratory
# Haemophilus
# Bordetella
# Legionella
o Zoonotic
# Yersinia
# Francisella
# Pastuerella
o Enteric
# Klebsiella
# Serratia
# Proteus
# Enterobacter

* Strict Aerobes
o Pseudomonas
* Anaerobes
o Bacteroides

Enterobacteriaceae
K. rhinoscleromatis
* Catarrhal
o purulent rhinorrhea
* Granulomatous
o mucosal nodules
* Cicatricial
o fibrosis
o stenosis

H. influenzae
Legionella

* Community and Nosocomial pneumonia
* contaminated water sources
B. pertussis
Zoonotic Gram Negative Rods

* Yersinia
o plague
* Franciscella
o tularemia
* Pasturella
o dog/cat bites

Pseudomonas
Anaerobic Bacteria

* Bacteroides
* Fusobacterium
* Peptostreptococcus
* Actinomyces
* Prevotella

Spirochetes

* Treponema
* Borrelia

Manifestations of Syphilis
Lyme Disease

* Cutaneous lesions
o erythema chronicum migrans
* Nonspecific symptoms
o malaise, fatigue, headache, fevers, chills, myalgias, arthralgias, lymphadenopathy
* Late manifestations
o neurologic
o cardiac

M. tuberculosis

* Pulmonary disease (82%)
* Extrapulmonary disease (18%)

ENT Manifestations of TB

* Scrofula
o matted lymphadenopathy: posterior triangle
* Laryngeal TB
o edema, ulcers, polypoid changes: arytenoids
* Oral TB
o painless ulcers: tongue
* Aural TB
o thickened TM-->hyperemia-->multiple perfs
o thin, watery otorrhea-->thick, cheesy d/c
M. leprae

Antibiotic Therapy

* Identify infecting organism
* Evaluate drug sensitivity
* Target site of infection
* Drug safety/side effect profile
* Patient factors
* Cost

Classification of Antibiotics

* Bacteriostatic
* Bactericidal
* Chemical Structure
* Spectrum of Activity
* Mechanism of Action

Mechanism of Action
Inhibitors of Cell Wall Synthesis
Beta Lactam Antibiotics

* Penicillins
* Cephalosporins
* Carbapenems
* Monobactams
Penicllins

* Derived from the fungus Penicillium
* Therapeutic concentration in most tissues
* Poor CSF penetration
* Renal excretion
* Side effects: hypersensitivity, nephritis, neruotoxicity, platelet dysfunction

Natural Penicillins

* Penicillin G, Penicillin V

Antistaphylococcal Penicillins
Aminopenicillins
Antipseudomonal Penicillins
Cephalosporins
Generations of Cephalosporins
Monobactams
Carbapenems
Vancomycin
Protein Synthesis Inhibitors
Tetracyclines
Aminoglycosides
Macrolides
Erythromycin
Alternate Macrolides
Chloramphenicol
Clindamycin
Inhibitors of Metabolism
Sulfonamides
Trimethoprim
Co-Trimoxazole (TMP/SMX)
Inhibitors of Nucleic Acid Function/Synthesis
Fluoroquinolones
Antimycobacterial Therapy
First-Line Agents
Antimycobacterials for Leprosy
Antibiotic Prophylaxis
Classification of Wounds
Classification of Wounds
Prophylactic Antibiotics
Effective Prophylactic Regimens
Topical Antibiotic Prophylaxis
Indications for Antibiotic Prophylaxis in ENT Surgery

Microbiology, Infections, and Antibiotic Therapy.ppt

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Microbiology in a Nutshell

Microbiology in a Nutshell
Presentation from nebo.edu

Yes, you will need to know this
Microbes
Viruses

* Microscopic (can’t see with the naked eye)
* nonliving particle
* Invades and reproduces inside a host.
* Contains DNA or RNA

Virus Multiplication

* Active
o Become sick within hours or days
* Hidden
o Illness can be delayed for weeks, months, or years
o Triggered by environment?

Bacteria

* Microscopic
* Prokaryotes (means they don’t have a nucleus)
* Living
* Contains DNA

Shapes of bacteria

* Spherical
* Rodlike
* Spiralshaped
* They can also be in chains
o Spherical chain

Bacteria Multiplication

* Sexual reproduction
o Two parents
o Conjugation (transfer of genetic material through bridge)
* Asexual reproduction
o Binary Fission-Simply splitting in two

Growth in Action

* Rapid, as fast as once every 20 minutes
* Continues until they run out of the basics
o Food
o Air
o Space

Parasites

* Organisms that live on or in a host and cause harm.
* Examples: Viruses, Bacteria, and tapeworms.
* Can a bacteria be a host?

How many can there be?

* These bubble-headed creatures are called bacteriophages, viruses that target bacteria. The head holds DNA and the tail acts as a needle attaching to a specific site on the bacterial cell wall, the virus squirts DNA through the tail into the bacterium. Ouch! They are among the smallest of organisms. You could fit about 680,000 of these creatures on the head of a pin.

What can you do?

* Get Vaccines
* Personal Hygiene
* Use Disinfectants
* Lines of Defense
o Skin
o Mucus barriers
o Immune System

Vaccines

Existing flu shots are 70 percent to 90 percent effective at preventing flu in healthy young people

* 50 percent effective in the elderly, (And even if the vaccines don't prevent the flu, they do tend to reduce symptoms and serious complications).

High Risk Groups

* aged 65 and older
* with chronic diseases affecting the heart, lung or kidneys
* with diabetes, immunosuppression, or severe anemia
* people in contact with doctors, nurses and nursing-home staff

Prevention

* "The current U.S. plan in the event of a pandemic is to vaccinate virtually the entire population," says epidemiologist Nancy Arden.
* Despite its advantages, less than 60 percent of the high-risk population gets the flu shot each year.

Microbiology in a Nutshell.ppt

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Esophageal Rupture

Esophageal Rupture
Presentation by: Erin M. Will
Overview

* Esophageal rupture is rare
o Roughly 300 cases reported per year
o The diagnosis is commonly missed/delayed
* Mortality is high
o Most lethal GI perforation
o Mortality falls with early dx/intervention
* Survival depends on rapid dx and surgery
o Within 24 hours of rupture: 70-75% survival
o Within 25-48 hours: 35-50% survival
o Beyond 48 hours: 10% survival

Etiology of Esophageal Rupture

* Traumatic Causes (MORE COMMON)1,2:
o Endoscopy or dilation procedures
+ Stent placement most common cause (up to 25% cases)
o Vomiting or severe straining
o Stab wounds / penetrating trauma
o Blunt chest trauma (rarely)
* Non-Traumatic Causes (LESS COMMON)1,2:
o Neoplasm / Ulceration of esophageal wall
o Ingestion of caustic materials

Demographics
* Spontaneous rupture:
o Middle-aged men
o Alcoholics
* Hx of recent esophageal instrumentation
* Chest Trauma
o Penetrating > Blunt

Anatomy

* Esophagus lacks serosa
o More likely to rupture
* Site of rupture:
o More commonly on left side
o Due to instrumentation: distal esophagus
o Spontaneous: posterolateral esophagus
* Tears are usually longitudinal

Pathophysiology

* Air, Saliva, and Gastric contents released
o mediastinitis
o pneumomediastinum
o empyema
o can progress to sepsis, shock, resp failure
Presentation

* Pain
o lower anterior chest / upper abdomen
o may radiate to left shoulder / back
* Vomiting >> Hematemesis
o hematemesis: think Mallory-Weiss/varices
* Dyspnea
* Cough (precipitated by swallowing)

On Exam

* Subcutaneous Emphysema
* Fever
* Tachycardia
* Tachypnea
* Cyanosis
* Upper Abdominal Rigidity
* Pneumothorax/Hydrothorax
* Respiratory Failure
* Sepsis
* Shock

Initial Imaging: X-ray

* PA and Lateral chest films
o Look for:
+ Hydrothorax (L side > R side)
+ Pneumothorax
+ Hydropneumothorax
+ Pneumomediastinum
+ SubQ emphysema
+ Mediastinal widening
+ Pleural Effusion (L side > R side)
Hydrothorax
Initial Imaging: X-ray
Subdiaphragmatic Air
Interventional Imaging
Gastrografin extravasation
CT scan
Pneumomediastinum
What to do next
Indications for conservative mgmt
What to do next

* Early surgical intervention reduces mortality rate: 1st 24 hours!
Indications for surgery

* Sepsis
* Respiratory Failure
* Shock
* Contamination of mediastinum
* Associated pneumothorax
Resources

Esophageal Rupture.ppt

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