What is the standard dose of erythromycin when treating s. pneumoniae, or similar bacteria?
Wе need tο know thе rіght dose ѕο wе won’t hаνе tο keep doing thе same experiment over аnd over again. Thе erythromycin wіll bе used іn thе form οf a disc οn a culture οf streptococcus pneumoniae іn a standard petri dish.
No one in their right mind would use erythromycin to treat strep pneumonia infections in this decade. So if you really wanted clinically relevant results, you should choose a different antibiotics. Somewhere in the range of 30% of s. pneumoniae are fully resistant to erythro – hence the loss of interest in this drug.
in the OLD days, these doses would be used:
250 mg q 6 hrs for standard pneumonia
500 mg q 6 hrs for legionella pneumonia.
Those are the doses used in humans of adult size. Don’t know the quantities of antibiotic that you need in a disc for in vitro testing — you could probably find that out from the most recent CLSI standards – or just ask your local hospital’s micro lab to tell you what they use.
For s. pneumonia, the most relevant antibiotics to test would currently be:
penicillin
moxifloxacin
ceftriaxone
imipenem
if you really HAVE to test a "macrolide", choose azithromycin – since that still rarely gets some usage clinically. Clarithromycin and erythromycin really do not.
Materials can be obtained from a biological supply catalog. Blank control disks and antibiotic disks are typically sold in packs of 50. I would suggest you use several different types of antibiotics that have been very commonly used; including both antibiotics that work on gram positive bacteria and antibiotics that work on gram negative bacteria. For example in addition to erythromycin, use penicillin, streptomycin, and tetracycline. I don’t know what the "standard" dosage is but I don’t think it matters since you’re going to innoculate the discs with your cultures not the other way around.
Below is a link to a bio supply house.
http://www.carolina.com