1. Infectious Disease I Flashcards
Identify the basic identification process of gram negative and gram positive organism.
Gram Positive
- appear purple/violet under microscope
- contain THICK peptidoglycan layer
Gram Negative
- appear red/pink under microscope
- contain THIN peptidoglycan layer
- contain second outer membrane
- Compare susceptibility and resistance with emphasis on the Kirby-Bauer antibiotic testing plate.
- Identify the clinical importance of the KB test in determining antibiotic treatment.
Susceptibility - determine which antibiotics effectively inhibit the growth of a given bacterial isolate
Resistance - no inhibition of growth of the bacterial
Kirby-Bauer test
- qualitative (susceptible v. intermediate v. resistant)
- zone of inhibition
Clinical importance
- reference method for organism-microbial combinations
- allows practitioner to know which antibiotics are susceptible to the bacteria and prescribe antibiotic therapy for patient
Identify Minimum Inhibitory Concentration (MIC) and explain the importance of its use when determining an antibiotic regimen.
Minimum Inhibitory Concentration (MIC)
- lowest concentration of antimicrobial that inhibits visible growth of bacteria
- quantitative measure of antimicrobial susceptibility, required to determine best therapeutic
Influences level of toxicity, cost, resistance, removal of “good bacteria” in the body allowing for opportunistic infections.
Explain how to interpret and apply the antibiogram of UW.
Angiogram - regional profile of antimicrobial susceptibility testing results or specific microorganisms to antimicrobial drugs.
Under each antibiotic, values are based as percentage (%) of susceptibility of organism to antibiotic.
Identify Methicillin-resistant Staphylococcus aureus (MRSA)
- Gram stain structure
- Specific generic first choice antibiotics/drug that is effective against MRSA
- Gram positive cocci, clusters
- First choice - Vancomycin
- - Alternative drugs: Doxycycline, Sulfamethoxazole / Trimethoprim (TMP-SMZ), Minocycline
Moraxella catarrhalis
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative cocci.
- Acute otitis media (children), acute exacerbation of COPD, acute bacterial rhinosinusitis
- Cefuroxime (FLQ)
Neisseria gonorrhoeae (gonococcus)
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative cocci.
- Gonorrhea (urogenital infection)
- Ceftriaxone + Azithromycin or Doxycycline
Neisseria meningitidis (meningococcus)
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative cocci.
- Meningitis (bacterial or community acquired)
- Penicillin
Staphylococcus, Methicillin-resistant
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram positive cocci
- MRSA
- Vancomycin
Streptococcus pyogenes (group A)
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram positive cocci
- Streptococcus pharyngitis
- Penicillin
Streptococcus agalactiae (group B)
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram positive cocci
- Neonatal bacteremia with meningitis and/or pneumonia
- Penicillin
Enterococcus species
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram positive cocci
- UTI, bacteremia, endocarditis, meningitis
- Ampicillin +/- gentamicin (faecalis), Vancomycin +/- gentamicin (faecium)
Haemophilus species
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative rods
- Meningitis, respiratory infections, otitis
- Ampicillin-clavulanate (resp. infection, otitis), Ceftriaxone (serious infections)
Escherichia coli
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative rods
- UTI, sepsis
- Nitrofurantoin, fosfomycin (UTI); Cefotaxime, ceftriaxone (sepsis)
Klebsiella pneumonia
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative rods
- Pneumonia
- Cephalosporins (TMP-SMZ, aminoglycoside)