Exam II ABX Types Flashcards
What are the Bacteria shapes?
Sphere - Cocci
Rod - Baillus
Spirochete - Spirilla
Gram-Negative vs Gram-Positive
Gram-Negative - Outer membrane with Lipopolysaccharides
Gram-Positive - Numerous Peptidoglycan as outer layer
Patterns of Gram-Positive organisms.
Clusters
Pairs
Chains
Staphylococci w/ positive Coagulase test.
Staph Aureus
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
Common Gram-Positive Organisms
Cocci
Streptococcus SP
Staphylococcus SP
Enterococcus SP
Peptostreptococcus SP (anaerobic)
Bacilli
Bacillus anthracis
Clostridium SP (anaerobic)
Corynebacterium SP
Listeria SP
Reactive Tests for Gram Negative Rods (GNR)
Oxidase Test
Positive = Purple
Lactose Test
Positive = Pink
Gram-Negative Characteristics
Gram Stain
Pink
Bacterial Shape
Bacilli/Cocci
Reactive Tests
Bacilli - Lactose Positive
Bacilli - Lactose Negative
Cocci - Nitrate Tests
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
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
Types of Encapsulated Organism Bacteria
Hemophilus FLU B
Streptococcus Pneumoniae (Pneumococcus)
Neisseria Meningitides (Meningococcus)
Group A & B Streptococcus
Klebsiella Pneumoniae
Salmonella Typhi
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
Normal Flora and location
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.
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
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
Increasing 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*
