BSC 431 Lecture Notes - Lecture 21: Respiratory Epithelium, Bronchitis, Serology
22 Mar 2016
School
Department
Course
Professor
Document Summary
Family legionellaceae consists of 4 genera but legionella is the most important pathogen. 53 species: about half implicated in human infections, others are found in the environment. L. pneumophila: causes 90% of all infections. Motile, slender, gram negative rods that can be extremely pleomorphic (cid:1) (cid:1) (cid:1) stain (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) Do not stain w/ common reagents; can be seen w/ dieterle"s silver. Require media w/ l-cysteine and iron for isolation. 3 lifestyles: free living, intracellular parasites of amoebae, ciliated protozoa and slime molds, biofilms, with other bacteria (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1) (cid:1, more resistant to disinfectants (very slow growth rate in the biofilm) Grows in a/c cooling towers: colonization best if >40 c. Grows in the presence of chlorine and other disinfectants. Impairment of respiratory defenses increases susceptibility: heavy alcohol use, smoking, old age. Hospital patients w/ underlying immune defects also susceptible: about 25% of cases are acquired in hospitals.
