First step to approach this problem is to eliminate Listeria monocytogenes (it is a gram positive ROD) and both staphylococcal species (Staph is always catalase positive), which leaves us with Streptococcus pneumoniae and Enterococcus faecalis.
Strep pneumoniae is an alpha hemolytic strep while enterococcus is typically gamma hemolytic, so seeing as there is no hemolysis on blood agar (meaning gamma hemolytic), Enterococcus is the correct answer. VRE (vancomycin resistant enterococcus) are also an important cause of nosocomial infections such as from his venous catheter.
Here is a good algorithm/flow chart for gram positive identification!
submitted by โcassdawg(1781)
First step to approach this problem is to eliminate Listeria monocytogenes (it is a gram positive ROD) and both staphylococcal species (Staph is always catalase positive), which leaves us with Streptococcus pneumoniae and Enterococcus faecalis.
Strep pneumoniae is an alpha hemolytic strep while enterococcus is typically gamma hemolytic, so seeing as there is no hemolysis on blood agar (meaning gamma hemolytic), Enterococcus is the correct answer. VRE (vancomycin resistant enterococcus) are also an important cause of nosocomial infections such as from his venous catheter.
Here is a good algorithm/flow chart for gram positive identification!