 Welcome back to our meds smarter lecture series where we're taking a smarter approach to preparing future physician Before we get started if you'll take just a quick minute and click that like button and also Subscribe and turn the bell on so that you'll be notified when we post new videos Let's continue on with some more clinical bacterology talking about gram positive organisms Beta hemolytic bacteria we've already talked about alpha hemolytic bacteria But what is a beta hemolytic bacteria consist of? These are gram positive cocci That cause a pale or clear area to surround that particular colony when it's placed on a blood auger plate So as you can see in this picture right here What we're seeing is complete clearing of blood around that particular organism on the plate So what's happening here? Well, this is complete lysis of those red blood cells So that bacteria is lysing those red blood cells Completely removing all of the internal structures of those red blood cells and it's turning that clear color around That particular microorganism there are several microorganisms that are beta hemolytic and those include Staphylococcus and Streptococcus in particular the Staphylococcus that are beta hemolytic are Catalyze and coagulase positive for the Streptococcus pyogenes or the group a strap you can see these as Bacitracin sensitive so they are sensitive to Bacitracin But they are Catalyze negative and then for the Streptococcus a galactate or group B strap These are resistant to Bacitracin and they are Catalyze negative as well. Let's talk about Staph aureus Staph aureus is probably one of the most well-known Bacteria's everybody has heard about Merca and Versa, but there's some other things We need to make sure we know about Staph aureus besides those two main things first and foremost obviously Staph aureus is gram positive. So what does that do that gives us those purple colonies under a gram stain? It is also beta hemolytic. So as we saw on our previous Portion that it will cause the red of the blood auger plate to turn clear or white It is Catalyze positive and it is coagulase positive and in clusters the particular part of Staph aureus that is the virulence factor or what makes it able to colonize certain locations is protein a so protein a is the virulence factor for Staph aureus and it will bind to the FC IgG and inhibit complement activation in phagocytosis Staph aureus particularly likes to colonize the nares or the nose the ears the axilla and the groin area You can see it Particularly anywhere throughout the skin, especially if it becomes infective However, this is where you most commonly see it. So now that we know a little bit about Staph aureus What conditions does it cause? Well first and foremost it causes inflammatory diseases So Staph skin infections are very very common for Staph aureus to be found organ abscesses pneumonia endocarditis septic arthritis and osteomyelitis all can be potential inflammatory diseases that are associated with an infection from Staph aureus Furthermore Staph lacoccus aureus can also cause a toxin-mediated disease. So we can see toxic shock syndrome scalded skin syndrome Rapid onset of food poisoning and then even abscesses as well a particular note on the food poisoning What's happening here is we're actually ingesting a preformed toxin that has a real short incubation period here Typically about two to six hours, and then you can see non-bloody diarrhea and vomiting From this food poisoning due to Staph aureus that toxin that has been preformed is heat stable So therefore it's not destroyed by just cooking the food if you found this material helpful for your studying Please like and consider subscribing to the channel also share this video so that more people can benefit from it like you have