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)
Pseudomonas species
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative rods
- Pyelonephritis (recurrent UTI)
- Piperacillin-tazobactam, ceftazidime/cefepime, imipenem/meropenem/doripenem/aztreonam, +/- aminoglycoside
Campylobacter jejuni
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram negative rods
- Food poisoning
- Azithromycin
Clostridium species
- Gram stain structure
- Most common clinical diagnosis
- First choice antibiotics/drug class
- Gram positive rods
- Gas gangrene, tetanus
- Penicillin
What is empiric antibiotic treatment and identify the importance of determining whether or not to start empiric treatment?
Antibiotics prescribed prior to confirming the pathogen and its susceptibility. Best educated guess based on source of infection.
Rarely helpful and may delay diagnosis if etiology is infectious (reduce sensitivity of blood cultures).
CYTOMEGALOVIRUS (CMV)
- Identify brief clinical findings of primary CMV infection.
CMV
- Clinical findings:
Immunocompromised
— Retinitis, retinopathy, esophagitis, IBD symptoms, cough, dyspnea, sputum, polyradiculopathy, myelitis, encephalitis
Immunocompetent
— fever, malaise, myalgias, arthralgias, splenomegaly
CYTOMEGALOVIRUS (CMV)
- Identify laboratory testing available for CMV.
- Laboratory test
Immunocompromised
— PCR assay (CMV DNA), tissue biopsy (organ involvement), ophthalmology refererral
Immunocompetent
— CBC (lymphocytosis, atypical), Chemistry (LFT), CMV DNA (IgM, IgG), viral load
CYTOMEGALOVIRUS (CMV)
- Explain treatment for CMV.
When to admit to hospital?
- Treatment
HIV/AIDS
- Antiretroviral therapy (ART), antiviral medications (Ganciclovir IV + foscarnet, valganciclovir, cidofovir)
Post-transplant, non-severe
- Valganciclovir PO, Ganciclovir IV
Severe CMV
- Ganciclovir IV
CYTOMEGALOVIRUS (CMV)
- When is hospital admission necessary?
- escalating CMV viral load at onset of illness
- risk of colonic perforation
- evaluation of unexplained, advanced encephalopathy
- initiation of treatment with IV anti-CMV agents
EPSTEIN BARR VIRUS (EBV)
- Identify clinical findings for typical patient with EBV.
Clinical findings
- Infectious mononucleosis (fever, sore throat, malaise, fatigue, anorexia, and myalgia)
- maculopapular rash (strep throat sx), conjunctival hemorrhage
- lymphadenopathy (posterior cervical) and splenomegaly
- upper eyelid edema
EPSTEIN BARR VIRUS (EBV)
- Explain the pitfalls and clinical use of Monospot test?
Clinical use:
- Serology test for IgG/IgM antibodies to EB virus capsid antigen
Pitfalls:
- Specific but not sensitive
- Positive after 4 weeks of onset
EPSTEIN BARR VIRUS (EBV)
- Treatment options for EBV
Treatment
- uncomplicated: supportive treatment (NSAIDS, salt rinses)
- complicated: corticosteroids, splenectomy
EPSTEIN BARR VIRUS (EBV)
- Identify complications and counseling for patient with EBV infections.
Complications
- bacterial pharyngitis
- splenic rupture, hepatitis, cholestasis, pericarditis, myocarditis
- malignancy
Counseling
- NO CONTACT SPORTS
INFLUENZA
- Explain the clinical findings for patient with seasonal influenza.
Clinical findings:
- fevers, chills, headache, malaise, myalgias
- runny/stuffy nose, sore throat, hoarseness, cough
- mild pharyngeal injection, flushed face, conjunctival redness, enlarged cervical LN
INFLUENZA
- Identify the transmission of influenza.
Transmission
Respiratory route by droplets.
INFLUENZA
- Identify the laboratory findings associated with influenza virus and diagnostic test.
Laboratory Findings and Diagnostic Tests
CBC - leukopenia
UA - proteinuria
Nasal and throat swabs have suboptimal sensitivity (60-80%)
Chest X ray usually negative.
INFLUENZA
- Identify complications associated with influenza and criteria for admission in patient with influenza.
Complications
- viral pneumonitis, shock, necrosis of respiratory epithelium, MI, PE, CVD, seizures, infection during pregnancy, Reye syndrome (fatty liver with encephalopathy in children)
Admissions Criteria
- limited availability of supporting services, pneumonia or decreased O2 saturation, changes in mental state, pregnancy
INFLUENZA
- Distinguish treatment options for influenza and timeframe for efficacious treatment.
Treatment options
- OSELTAMIVIR (tamiflu) - PO, 75 mg BID for 5 days
- Zanamivir - inhaled, 2 puffs BID for 5 days
- Peramivir - IV, 600mg or daily for 5 days (inpatient)
Timeframe
- Earlier the better, benefits of antiviral therapy after 48 hours is reduced.
INFLUENZA
- Explain the immunization efficacy of influenza virus.
Immunization efficacy
- prevent influenza and complications
- reduce hospitalization
- decreased mortality among hospitalized patients
