Susceptibility of mucoid Pseudomonas aeruginosa to gentamicin disks.

To compare the in vitro susceptibility of mucoid and nonmucoid Pseudomonas aeruginosa 
to gentamicin, 144 isolates of both mucoid and nonmucoid P aeruginosa 
were cultured from throat swab and sputum specimens from 29 patients 
with diagnosed cystic fibrosis. Mucoid forms of P aeruginosa from throat 
swab cultures were all susceptible to gentamicin, whereas only 85.5% of 
the mucoid strains from sputum cultures were susceptible. Nonmucoid strains from 
throat swab and sputum cultures were 85.1% and 77.8% susceptible, respectively. 
Since the differences in susceptibility between the four groups of organisms 
were not significant (P < 0.05), it was concluded that these 
data show no real differences in susceptibility to gentamicin between the 
mucoid and nonmucoid strains. 