Dura, Penny - Herxheimer, Gram stain

[Guest guest]

Dura, in saying herx is caused by gram-negs, I'm totally sure Penny

didnt mean to exclude the spirochetes.

As you say, spiros dont take the Gram stain. That makes them literally

gram-negative. And they are usually included, I think, when people say

" gram-negative bacteria. "

However, as I think Dura may be pointing out, the spirochetes are not

particularly related to the typical gram-negative bacteria. They have

their very own phylum. Like the typical gram-negative bacteria, they

have an outer membrane beyond the cell wall and plasma membrane (thats

why their cell walls dont take up the Gram stain easily - it is not

excposed like the cell walls of gram-positives). However, the outer

membrane of spirochetes is very different from that of typical

gram-negatives (according to Radolf). The whole construction is

really different. Spirochetes lack liopolysacharide (=LPS=endotoxin).

I cant remember whether typical g-neg bacteria are more closely

related to each other than to g-pos bacteria. I think there is

controversy about bacterial phylogeny in general, if not on this

particular point. The fact is, bacteria frequently pick up genes from

one another, possibly to the extent that there is no real phylogenetic

tree, just a phylogenetic network that cant really be untangled.