Poaceae groups, using the C3 and C4 photosynthetic pathways for carbon fixation. The C4 grasses have a photosynthetic pathway, linked to specialized Kranz leaf anatomy, which allows for increased water use efficiency, rendering them better adapted to hot, arid environments and those lacking in carbon dioxide. The C3 grasses are referred to as "cool-season" grasses, while the C4 plants are considered "warm-season" grasses. The grass family is one of the most widely distributed and abundant groups of plants on Earth. Grasses are found on every continent, including Antarctica with the presence of Antarctic hair grass on the Antarctic Peninsula. Grasses are
HACEK organisms conjunctivitis, pneumonia, arthritis, osteomyelitis, and periodontal infections. The treatment of choice for HACEK organisms in endocarditis is the third generation cephalosporin and β-Lactam antibiotic ceftriaxone. Ampicillin (a penicillin), combined with low-dose gentamicin (an aminoglycoside) is another therapeutic option. HACEK organisms The HACEK organisms are a group of fastidious gram-negative bacteria that are an unusual cause of infective endocarditis, which is an inflammation of the heart due to bacterial infection. HACEK is an abbreviation of the initials of the genera of this group of bacteria: "Haemophilus", "Aggregatibacter" (previously "Actinobacillus"), "Cardiobacterium", "Eikenella", "Kingella". The HACEK organisms are a normal part of the