Exam II ABX Types Flashcards by Brian Fisher

What are the Bacteria shapes?

Sphere - Cocci

Rod - Baillus

Spirochete - Spirilla

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Gram-Negative vs Gram-Positive

Gram-Negative - Outer membrane with Lipopolysaccharides

Gram-Positive - Numerous Peptidoglycan as outer layer

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Patterns of Gram-Positive organisms.

Clusters

Pairs

Chains

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Staphylococci w/ positive Coagulase test.

Staph Aureus

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Gram-Positive Characteristics

Gram Stain

Purple

Bacterial Shape

Cocci/Bacili

Bacterial Pattern

Cocci

Chains/Pairs/Clusters

Bacilli

Usually no pattern

Reactive Tests

Cocci - Chains - Hemolysis +/- Lancefield Classification

Cocci - Pairs - Hemolysis +/- Lancefield Classification

Cocci - Clusters - Coagulase Test

Bacilli - Usually no pattern - Other tests

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Common Gram-Positive Organisms

Cocci

Streptococcus SP

Staphylococcus SP

Enterococcus SP

Peptostreptococcus SP (anaerobic)

Bacilli

Bacillus anthracis

Clostridium SP (anaerobic)

Corynebacterium SP

Listeria SP

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Reactive Tests for Gram Negative Rods (GNR)

Oxidase Test

Positive = Purple

Lactose Test

Positive = Pink

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Gram-Negative Characteristics

Gram Stain

Pink

Bacterial Shape

Bacilli/Cocci

Reactive Tests

Bacilli - Lactose Positive

Bacilli - Lactose Negative

Cocci - Nitrate Tests

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Common Gram-Negative Organisms

Cocci

Neisseria gonorrhoeae

Neisseria meningitides

Moraxella SP

Bacilli

Lactose Fermentation

Citobacter SP (may appear as non-lactose fermenter initially as it is slow)

Escherichia Coli

Enterobacter SP

Klebsiella SP

Serratia SP (may appear as non-lactose fermenter initially as it is slow)

Non-lactose Fermentation

Pseudomonas SP (oxidase +)

Proteus SP

Yersinia SP

Acinetobacter SP

Bacteroides SP

Legionella SP

Campylobacter SP

Salmonella SP

Shigella SP

Stenotrophomonas SP

Escherichia Coli

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Encapsulated Organisms

Bacteria that have an extra thick layer of Polysaccharide

Unable to undergo phagocytosis

PTs without B-Cells or lack a spleen have high mortality from infections

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Types of Encapsulated Organism Bacteria

Hemophilus FLU B

Streptococcus Pneumoniae (Pneumococcus)

Neisseria Meningitides (Meningococcus)

Group A & B Streptococcus

Klebsiella Pneumoniae

Salmonella Typhi

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Atypical Bacteria

Incomplete bacteria

Zoonotic

Lack of a Cellular Wall

Replicate within host cells

Difficult to see on a microscopic or staining properties

Types

Mycoplasma Pneumoniae

Chlamydia Pneumoniae

Rickettsias

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Normal Flora and location

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Why are some infections more severe than others?

Genetics

Type of Bacteria

Endotoxins* - Part of the outer portion of the cell wall of Gram-Negative bacteria. They are liberated when the bacteria die and the cell wall breaks apart.
Exotoxins* - Produced inside mostly Gram-Positive bacteria as part of their growth and metabolism. They are then secreted or released following lysis into the surrounding medium.

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Resistance to Antibiotics

ESKAPE pathogens

Enterococcus faecium, Staphylococcus aureus, Klebisella. Acinetobacter, Pseudomonas, Enterobacter

Resistance mechanisms: Efflux pumps, Enzymes for antibiotic degredation, Cell wall alteration, protein synthesis variation.

Pass along resistance by exchanging plasmids

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Empiric Therapy

Antibiotics chosen prior to knowing ID and Sensitivity of pathogens

Important to understand types of bacteria that are known for causing disease

Previous infections

Local Sensitivity

De-escalation

Narrowing therapy from broad agents

Antimicrobial Stewardship

Preserving broad-spectrum antibiotics

Limit development of resistance

Alpha-Hemolytic

Streptococcus Viridans

Streptococcus Pneumoniae (Pneumococcus)

Beta-Hemolytic

Streptococcus Pyrogenes (Group A)

Streptococcus Agalactiae (Group B)

Streptococcus Equi (Group C)

Streptococcus Bovis (Group D)

Streptococcus Anginosus (Group F)

Streptococcus Dysgalactiae (Group G)

Streptococcus (Group H)

Staphylococcus

Staph Aureus (MRSA/MSSA)

Coag Positive

Prodices Toxin

Methicillin-Resistant VS Methicillin-Sensitive

Staph Epidermidis

Coag Neg

Common on skin

Not Susceptible to many antibiotics

Usually not virulent

Contaminant in blood cultures

Can cause wound, bone infections

Enterococcus

E. Faecium

Not Virumlent

Vancomycin resistant (VRE) vs. Susceptible

E. Faecalis

Not Virulent

Problematic for Immunocompromised Patients

Usually susceptible to vancomycin and penicillins

HNM

Gram-Negative Cocci

Haemophilus (coccobacilli)

Neisseria

Moraxella

Common infections of Haemophilus and Moraxella include upper and lower respiratory tract infections.

Common infections of Neisseria are meningitis and STDs

Atypical

Rarely grow on gram stain

Mycoplasma Pneumoniae

Chlamydia Pneumoniae

Often treat without knowing bacteria

Common infections: Upper respiratory tract infections, walking pneumonia

Enteric Gram Negatives

Group includes **GNR** (Gram Negative Rods), **Lactose, and non-Lactose fermenting** organisms. Common Pathogens: **E. Coli, Proteus, Serratia, Acinetobacter, Citobacter, Klebsiella, Legionella pneumoniae** Types of infections (**community**): **UTI, Abdominal infections** Types of infections (**hospital**): **Pneumonia, UTI** - *Tend to be More Drug Resistant.* **_Many have**_ _**potential**_ _**to develop resistance to antibiotics by plasmid exchange._**

Anaerobes

Rarely anaerobes are virulent by themselves (co-infection) Worry with abscesses in peritoneal, brain, and lung *Requires incision and drainage* C.diff is an infection on the rise *Associated with Antibiotic use*

Gram + Anaerobes

Clostridium sp (Bacilli) Actinomyces sp (Bacilli) Lactobacillus sp (Bacilli) Propionobacterium sp (Bacilli) Peptostreptococcus (Cocci)

Gram - Anaerobes

Bacteroides fragilis (Bacilli) Fusobacterium sp (Bacilli) Porphyromonas sp (Bacilli) Veilonella sp (Cocci)

Important Bacteria on the rise

**MRSA** Increasing infection rates inside and outside of hospital **VRE** *I*ncreasing colonization and infections in hospitals **C. diff** Increasing infections post-antibiotic use **MDR GNR** S.P.A.C.E. Organisms - Extended spectrum beta-lactamase inhibitor ESBL * Serratia* * Pseudomonas* * Acinetobacter* * Citobacter* * Enterobacter*

Antibiotic cellular sites of action

Cell Wall *Cross-linking of peptidoglycan or membrane depolarization* Protein synthesis *Inhibit ribosomes - 30s and 50s subunit* DNA/RNA synthesis and replication *Inhibit DNA gyrase or RNA* Need to be specific to bacteria so they do not damage human cells

Type 1 Pattern of activity

***Aminoglycosides, Daptomycin, Flouroquinolones*** MAximize concentrations *24 Hr AUC/MIC Peak (Cmax/MIC)*

Type 2 Pattern of Activity

***B-lactams, Linezolid, Erythromycin*** Maximize duration of exposure *T\>MIC*

Type 3 Pattern of Activity

***Azithromycin, Clindamycin, Tetracyclines, Vancomycin, Metronidazole*** Maximize the amount of drug *24 hour AUC/MIC*

Dose adjustments

**Many antibiotics require adjustment of renal or liver dysfunction** **Still allows for optimization of PK/PD parameters** Lower dose, more frequent admin (continuous or extended infusions) *T\>MIC* Same of higher dose decreased frequency * Peak (Cmax/MIC)* * 24 Hr AUC/MIC*