Gram Positive Bacteria Flashcards
List the common toxins associated with Staph aureus.
Enterotoxin
Exotoxin
Coagulase
Panton-Valentine leukocidin
You are treating a child for infection and there is the presence of the virulence factor Panton-Valentine. What bacteria are you dealing with?
Staph aureus
Are drugs such as ceftaroline or quinupristin-dalfopristin suitable for MRSA infections in children?
No because they are not FDA approved for use in children.
You are treating and infant for overwhelming sepsis due to gram positive bacteria in clusters in the blood stream. What empiric antibiotic regimen would you give?
Nafcillin +/- vancomycin. Don’t choos vancomycin by itself because nafcillin is more effective for MSSA than vanco.
True or false: Impetigo can be due to Staph or Strep.
True.
You are seeing a child in ICU with a proven Staph aureus brain abscess. What is also a likely condition in this child?
Cyanotic heart lesion. Staph aureus CNS infections are uncommon but brain abscesses are associated with cyanotic heart lesions.
You are treating a patient with TSS and the blood culture is negative. What organisms would then suspect? What if it did grow gram positive cocci?
Staph TSS usually has a negative blood culture. When positive, this is more often associated with Strep pyogenes TSS.
What organisms commonly cause impetigo?
Staph and strep
50% of TSS cases are associated with what population?
Menstruating females
What are the criteria for diagnosing toxic shock syndrome?
Temp > 102
SBP low 3 organ involvement
Negative serology for RMSF, leptospirosis, measles
What is the most common cause of food poisoning in the US?
Staph aureus
What organism is associated with food poisoning due to rice?
Bacillus cereus
You are treating a 13 year old child for infection of his VP shunt. What organism is most likely?
Coag-negative staph such as Staph epi
A 16 year old girl grew Staph saprophyticus in her urine culture. Should this be treated?
Yes, even if she is asymptomatic.
Which of the following antibiotics would be effective in treating a UTI with Staph saprophyticus? (More than one are valid)
Bactrim Nitrofurantoin Cefdinir Cefalexin Ceftriaxone
All except cefdinir, ceftriaxone. Second and third generation cephalopsopins are not effective against Staph saprophyticus
What is the most common organism in otitis media?
Strep pneumoniae
You are treating a patient empirically for otitis media. What antibiotic should you use first? How long of a time with no response should you wait before shifting therapy? What would you switch to?
Amoxicillin (high dose)
48 hours
Amox/clav or 2nd or 3rd gen cephalosporin
An 11-month old child with unilateral otitis media is seen in office. He does not appear unwell. Should he be treated with antibiotics? What is the guideline?
No it is safe to observe so long as they do not have otorrhea. Also safe for bilateral otitis if kid is > 2.
The guideline says 6 mo - 2 years with unilateral disease and otherwise well, ok to observe for 48-72 h.
A 3 year old child with non-purulent bilateral otitis is seen in office. He appears only mildly ill. He is leaving the country in two days. Should he be treated with antibiotics? What is the guideline?
Yes. It’s bilateral and this can be observed at his age but he cannot get close follow-up in 48-72 hours. Since you can’t reassess, you have to treat.
True or false: a child in the icu has a systemic strep infection and is seriously ill. The serotype is 19A. This proves he was not immunized with Prevnar.
False. Prevnar doesn’t cover this. It has become the most common strain in immunized children with invasive strep infection. It is also associated with increased abx resistance.
What particularly relevant strep strain is covered by PCV13 vs. PCV7?
Strep serotype 19A. Even older kids should get this if they are at risk.
True or false: strep pneumo is the most common cause of all pneumonia in kids.
False. Viral infections are most common. Strep is, however, the most common bacterial cause.
Other than E. coli O157:H7, what is the second most common cause of HUS?
Invasive strep pneumo.
A 2 month old infant has recovered from strep pneumo meningitis. What must be closely monitored at his well child checks?
Hearing. Up to 30% will suffer hearing loss.
What cell surface protein is a determinant of strep pyogenes virulence?
M protein
To avoid the complications associated with strep pyogenes infection, antibiotics must be started within how many days?
- That’s why you have time to wait on strep culture.
A 9 year old boy is in your clinic with a reddish sandpaper-like rash on his trunk and shoulders. He has lighter skin color around his lips. What infection should you be concerned about?
Strep pyogenes (scarlet fever)
A 9 year old boy is in your clinic with a reddish sandpaper-like rash on his trunk and shoulders. He has lighter skin color around his lips. What other findings would you look for that would support you suspicion of scarlet fever?
Pastia lines
Antecubital fossa rash
Flexor creases rash
Later in the coarse, desquamation.
How are impetigo and erysipelas the same? How are they different?
Both are most commonly strep infections. Erysipelas is infection of the deeper tissues. It is tender whereas impetigo is not tender.
You are seeing a 4 you old with honey-crusted lesions around his mouth. What symptom would change your opinion that this is impetigo?
If they were painful. Impetigo is not usually painful.
Infection with or recent infection with what virus is a risk factor for group A strep cellulitis?
Varicella