Bacteriology Flashcards
(a) Doxycycline
(b) Amoxicillin
(c) Cephalexin
(d) Loratedine
A diagnosis of early Lyme disease can be made based on this patient’s clinical findings and history of exposure in an endemic area. Erythema migrans can present before adaptive immune response occurs. Serologic testing is not required (and will often come back negative) in patients with localized Lyme disease. Although doxycycline is generally the preferred treatment, it should be avoided in pregnant women and children. Early Lyme disease can also be treated with a course of amoxicillin or cefuroxime for two to three weeks.
How would you manage this patient’s reaction?
FiguOfficial Account
A 32-year-old female presents with a headache and a rash on her trunk and extremities. She has had unprotected sex with multiple partners over the last two months, but denies any history of sexually transmitted infections. Examination reveals generalized non-tender lymphadenopathy, a diffuse macular rash on her chest and arms, and patchy hair loss. Venereal Disease Research Laboratory (VDRL) and fluorescent treponemal antibody-absorption (FTA-ABS) tests are both positive, and she is given a single dose of penicillin G benzathine intramuscularly. She returns within a few hours with a worsening rash (seen here), myalgia, and a fever. Which of the following is the next best step in managing this patient’s reaction?
Commence doxycycline
Supportive treatment
Intramuscular adrenaline
Antihistamines
Supportive treatment
This patient’s initial presentation is suggestive of secondary syphilis, a systemic illness that follows primary infection with the bacterium Treponema pallidum when left untreated. Treatment of early syphilis can result in the Jarisch-Herxheimer reaction (as seen here), an acute and self-limited reaction, occurring in up to 35% of cases, that typically develops within hours of receiving therapy. The initial rash may worsen and can be accompanied by headache, myalgia, diaphoresis, and hypotension. While the mechanism by which this rash develops is not well understood, it is thought to result from the release of lipoproteins from killed organisms. Symptoms often resolve spontaneously within 12 to 24 hours, however patients may benefit from supportive treatment such as non-steroidal anti-inflammatory drugs (NSAIDS) or other antipyretics.
What is Lancefield classification?
It is a serological classification of b-haemolygic strep based on the carbohydrate composition of the cell wall
Describe the classification of b-haemolytic strep
“Lancefield classification - based on cell wall carbohydrates. <br></br>
Groups A-H, L, N, R & S <br></br>”
What is the name for group A strep?
S. pyogenes
What is the name for group B strep?
S. agalactiae
What is the name for group D strep?
Enterococci, S bovis
What is the other name for group E strep?
S. milleri and S. mutans
What is the difference between Lancefield and non-Lancefield strep?
“Lancefield are b-haemolytic
All other strep are non-Lancefield”
Describe the classification of strep?
“a-haemolytic
b-haemolytic
gamma-haemolytic”
What are the 2 species of Strep that are b-haemolytic and how can they be distinguished on culture?
"S. pyogenes <br> S. agalactiae <br> <br> Distinguised by bacitracin <br> Pyogenes (A) is sensitive <br> Agalactiae (b) is resistant"
What are the 2 species of alpha-haemolytic strep and how are they distinguished on culture?
What are the 2 species of alpha-haemolytic strep and how are they distinguished on culture?
“Which of the following is responsible for this patient’s most likely diagnosis?
A 75-year-old female presents with a two-year history of a persistent cough and fatigue. The cough is occasionally productive of purulent sputum. She was treated for a community-acquired pneumonia two years earlier and underwent an anterior cervical discectomy and fusion previously, but is otherwise well. On examination, she appears well-groomed, polite, and thin. Chest auscultation reveals wheezing in the mid zones bilaterally and a later chest X-ray and CT scan demonstrate the findings seen here. Which of the following is responsible for this patient’s most likely diagnosis
Klebsiella pneumoniae
Pseudomonas aeruginosa
Aspergillus fumigatus
Mycobacterium avium-intracellulare”
This patient’s clinical presentation and imaging are suggestive of Lady Windermere syndrome, a pulmonary infection with Mycobacterium avium-intracellulare that is limited to the right middle lobe or lingula. The condition, typically seen in elderly immunocompetent females with no significant history of smoking or pulmonary disease, is thought to result from the voluntary suppression of a cough. The accumulation of secretions predisposes patients to infection, especially in the right middle lobe which has a relatively long and narrow bronchus. Imaging demonstrates an interstitial and/or nodular pattern, and sputum or bronchial washings will isolate the responsible organisms. Management is aimed at the underlying infection.”
