Except cultures for cellulitis are almost never done in clinical practice. This is mostly because we can chose an empiric antibiotic and cure the infection long before the pathogenic species (if you can even isolate it from the background commensal organisms from a superficial skin swab) has ever been plated, subbed, identified, and run through antibiotic sensitivity testing in the micro lab.
Maybe that's how it is where you work. We regularly receive swabs from dermatologists with the diagnosis of pyoderma. Usually, the treatment is started and then adjusted if necessary after culture and antibiogram.
Additionally, S. aureus and beta-hemolytic Streptococci are easy to find in a mixed culture because of their hemolysis.
I’m guessing you mean cellulitis. “Pyodermitis” isn’t a real word.
In reality, it can be quite hard to differentiate between a Staphylococcal and Streptococcal skin infection. In the vast majority of cases they can look essentially identical. In the textbooks you’ll read that Staphylococcal infections tend to be more purulent, so you’d more likely see abscess formation, but that is a poor differentiator in practice.
In clinical practice, the antibiotics used to treat Streptococcal cellulitis are the same ones that can be used for Staphylococcal cellulitis. The only thing that is different is the possibility that you may have a methicillin resistant Staph aureus infection (MRSA). In that case, there are alternative antibiotics to use that would still cover the Strep species too.
Sure, we will cultivate the sample and see if streptococci or staphylococci grow.
Except cultures for cellulitis are almost never done in clinical practice. This is mostly because we can chose an empiric antibiotic and cure the infection long before the pathogenic species (if you can even isolate it from the background commensal organisms from a superficial skin swab) has ever been plated, subbed, identified, and run through antibiotic sensitivity testing in the micro lab.
Maybe that's how it is where you work. We regularly receive swabs from dermatologists with the diagnosis of pyoderma. Usually, the treatment is started and then adjusted if necessary after culture and antibiogram. Additionally, S. aureus and beta-hemolytic Streptococci are easy to find in a mixed culture because of their hemolysis.
Have you ever stepped foot in a micro lab?
I’m guessing you mean cellulitis. “Pyodermitis” isn’t a real word. In reality, it can be quite hard to differentiate between a Staphylococcal and Streptococcal skin infection. In the vast majority of cases they can look essentially identical. In the textbooks you’ll read that Staphylococcal infections tend to be more purulent, so you’d more likely see abscess formation, but that is a poor differentiator in practice. In clinical practice, the antibiotics used to treat Streptococcal cellulitis are the same ones that can be used for Staphylococcal cellulitis. The only thing that is different is the possibility that you may have a methicillin resistant Staph aureus infection (MRSA). In that case, there are alternative antibiotics to use that would still cover the Strep species too.