40.Greenish sputum is due to which of the following?fmge-march 2012
a.pseudomonas
b.s.pneumonia
c.c.difficle
d.s.aureus
answer : a
Pseudomonas aeruginosa, the bacteria that causes life-threatening lung infections in those with cystic fibrosis, is easily recognizable by the characteristic green sputum. The green color is caused by pigments called phenazines.
Pseudomonas is a gram-negative rod.
Pseudomonas aeruginosa has become an important cause of infection, especially in patients with compromised host defense mechanisms. It is the most common pathogen isolated from patients who have been hospitalized longer than 1 week. It is a frequent cause of nosocomial infections such as pneumonia, urinary tract infections (UTIs), and bacteremia. Pseudomonal infections are complicated and can be life threatening.
amazing facts:
diphtheria, pertussis, cholera, and pseudomonas they all have extotoxin that work by ADP ribosylation.
Cholera toxin ADP-ribosylates G proteins, causing massive fluid secretion from the lining of the small intestine, resulting in life-threatening diarrhea.
P. aeruginosa ADP-ribosylates cytoskeleton and GTP-binding proteins.
Diphtheria toxin - It catalyzes the ADP-ribosylation of eukaryotic elongation factor-2 (eEF2), inactivating this protein.
Pertussis toxin - PT catalyzes the ADP-ribosylation of the α subunits of the heterotrimeric G proteins Gi, Go, and Gt. This prevents the G proteins from interacting with G protein-coupled receptors on the cell membrane, thus interfering with intracellular communication. The Gi subunits remain locked in their GDP-bound, inactive state, thus unable to inhibit adenyl cyclase activity, leading to increased cellular concentrations of cAMP.
Increased intracellular cAMP affects normal biological signaling. The toxin causes several systemic effects, among which is an increased release of insulin, causing hypoglycemia. Whether the effects of pertussis toxin are responsible for the paroxysmal cough remains unknown.
