[The enzymatic degradation of formaldehyde by isolates of Pseudomonas aeruginosa].

The capacity of 12 Ps. aeruginosa-strains to enzymatically degrade Formaldehyde was tested. These strains, derived from environmental and patient samples, were previously passaged 25 times in increasing formaldehyde-concentrations, in a micromodification of the bacteriostasis test. The formaldehyde-degradation was detected photometrically with the sulfite-pararosaniline-method. Furthermore, in 4 of the 12 strains the activity of a formaldehyde dehydrogenase assumed to be the degrading agent was determined. The tested strains exhibited a markedly differing resistance to formaldehyde, some environmental isolates growing even at concentrations in the range of commonly used disinfectant solutions. The exponential growth phase of the inoculum and the reduction of formaldehyde-content coincided. The strains with the highest formaldehyde-resistance showed a formaldehyde-dehydrogenase activity higher by approximately a factor 100 compared with the rather sensitive ATCC-strain. This dehydrogenase activity, in addition to possible extra- and intracellular penetration barriers, could be a causal factor for an increased formaldehyde-resistance.