GRAM-POSITIVE BACTERIA HIGH G + C GRAM-POSITIVE BACTERIA —these belong to the phylum Actinobacteria. Many are pleomorphic and several are filamentous. 1. Mycobacterium--these are aerobic, non-endospore-forming rods that occasionally exhibit filamentous growth. They have a distinctive cell wall, which is similar in some ways to that of gram-negative bacteria, although they usually stain gram-positive. Instead of a true outer membrane, they deposit a thick waxy layer of mycolic acid, which gives them great resistance to drying and also prevents many antibiotics and disinfectants from entering the cell. Nutrients also enter the cell slowly, which results in unusually slow growth. It is this layer of mycolic acid which makes these bacteria stain acid-fast. Most species live in soil and water and only occasionally are pathogenic a. Mycobacterium tuberculosis —tuberculosis
This is the end of the preview. Sign up
access the rest of the document.
This note was uploaded on 01/23/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.