Pseudomonas biocide resistance

Burkholderia (formeriy Pseudomonas) cepacia is intrinsically resistant to a number of biocides, notably benzalkonium chloride and chlorhexidine. Again, the outer membrane is likely to act as a permeability barrier. By contrasL Ps. stutzeri (an organism implicated in eye infections caused by some cosmetic products) is invariably intrinsically sensitive to a range of biocides, including QACs and chlorhexidine. This organism contains less wall muramic acid than other pseudomonads but it is imclear as to whether this could be a contributory factor in its enhanced biocide susceptibility. 

Sondossi M. The effect of fifteen biocides on formaldehyde resistant strains of Pseudomonas aeruginosa. J Ind Microbiol 1986 1 87-96. 

Pseudomonas aeruginosa Gram-negative, micro-aerobic rod General environmental contaminant Quintessential opportunist pathogen High resistance to antibiotics and biocides Biofilm-former... 

Sondossi, M., Rossmoore, H. W. and Lashen, E. S., 1999. Influence of biocide treatment regimen on resistance development to methyl-chloro-/methylisothiazolone in Pseudomonas aeruginosa. International Biodeterioration Biodegradation 43, 85-92. 

ASTM G 22, Resistance of Plastics to Bacteria The test protocol is similar to G 21 specimens are inoculated (usually) with Pseudomonas aeruginosa, an opportunistic soil bacterium that is a hazard to immune-compromised persons. The zone of inhibition is sometimes determined. This should not be combined with fungus resistance testing, as Pseudomonas can metabolize a variety of fungi (instead of the biocide-containing nutrient). 

---