Bactericidal activity of disinfectants against certain bacterial strains. Klebsiella pneumonia

Twenty disinfectants were tested against a strain of K. pneumoniae. A suspension test with incremental addition of microorganisms was used. The influence of interfering substances (proteins and hard water) on the activity of disinfectants was also determined. Iodine compounds were influenced by proteins in distilled and hard water. The presence of mineral ions inactivated the polyvinylpyrrolidone-iodine 10% and chloroxylenol preparations against K. pneumoniae. The activity of some iodine products disappeared at the second and third incremental addition of microorganisms; the chloroxylenol and the phenolic compounds were inactivated by proteins at the third incremental addition. The sensibility of K. pneumoniae to the other disinfectants was not influenced by proteins, ions and incremental bacterial additions.