According to this textbook:
P aeruginosa, for example, which is extremely resistant to antibacterial agents, the outer membrane is 100 times less permeable than that of E coli.[pg.no 27]
and then on the same page:
The porins of diferent species have diferent exclusion limits, ranging from molecular weights of about 600 in E coli and S typhimurium to more than 3000 in P aeruginosa.
How can P. aeruginosa have lesser permeability than E. coli, if its exclusion limit is greater than that of E.coli?
This source claims that
OprF provides P. aeruginosa outer membrane with an exclusion limit of 500 Da.
This( 500 Da.) is near than that of E. coli's 600 Da., so how is it exteremely resistant?