Related Experiment Video
Updated: Jul 7, 2026

Use of Galleria mellonella as a Model Organism to Study Legionella pneumophila Infection
Published on: November 22, 2013
Effectiveness of disinfectants used in cooling towers against Legionella pneumophila
1Laboratorio de Legionella, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain.
Background:
Legionella persists in man-made aquatic installations despite preventive treatments. More information about disinfectants could improve the effectiveness of treatments. This study tests the susceptibility of Legionella pneumophila serogroup (sg) 1 against 8 disinfectants used in cooling tower treatments.
Methods:
We determined the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and bactericidal effect of sodium hypochlorite (A), hydrogen peroxide with silver nitrate (B), didecyldimethylammonium chloride (C), benzalkonium chloride (D), tributyltetradecylphosphonium chloride (E), tetrahydroxymethylphosphonium sulfide (F), 2,2-dibromonitropropionamide (G) and chloromethylisothiazolone (H) against 28 L. pneumophila sg 1 isolates.
Results:
MIC and MBC values were equivalent. Bacteria are less susceptible to disinfectants F, B, D and A than to H, E, C and G. All disinfectants induced a bactericidal effect. The effect rate is dose dependent for G, H, F and B; the effect is fast for the rest of disinfectants at any concentration. The bactericidal activity of disinfectants A, G and F depends on the susceptibility test used.
Conclusions:
All disinfectants have bactericidal activity against L. pneumophila sg 1 at concentrations used in cooling tower treatments. Results depend on the assay for some products.
Related Concept Videos
Antimicrobial Effectiveness
Chemical Agents for Microbial Control
Physical Methods for Controlling Microbial Growth: Radiation and Filtration
Physical Methods for Controlling Microbial Growth: Temperature
Biological Methods for Microbial Control