Relationship between Legionella pneumophila and Acanthamoeba polyphaga: Physiological status and susceptibility to chemical inactivation
- Aston Univ., Aston Triangle, Birmingham (United Kingdom)
- Univ. of Manchester (United Kingdom)
Survival studies were conducted on Legionella pneumophila cells that had been grown intracellulary in Acanthamoeba polyphaga and then exposed to polyhexamethylene biguanide (PHMB), benzisothiazolone (BIT), and 5-chloro-N-methylisothiazolone (CMIT). Susceptibilities were also determined for L. pneumophila grown under iron-sufficient and iron-depleted conditions. BIT was relatively ineffective against cells to PHMB and CMIT. The activities of all three biocides were greatly reduced against L. pneumophila grown in amoebae. PHMB (1 [times] MIC) gave 99.99% reductions in viability for cultures grown in broth within 6 h and no detectable survivors at 24 h but only 90 and 99.9% killing at 6 h and 24 h, respectively, for cells grown in amoebae. The antimicrobial properties of the three biocides against A. polyphaga were also determined. The majority of amoebae recovered from BIT treatment, but few, if any, survived CMIT treatment or exposure of PHMB. This study not only shows the profound effect that intra-amoebal growth has on the physiological status and antimicrobial susceptibility of L. pneumophila but also reveals PHMB to be a potential biocide for effective water treatment. In this respect, PHMB has significant activity, below its recommended use concentrations, against both the host amoeba and L. pneumophila.
- OSTI ID:
- 6962450
- Journal Information:
- Applied and Environmental Microbiology; (United States), Vol. 58:8; ISSN 0099-2240
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANTIBIOTICS
BIOLOGICAL EFFECTS
LEGIONELLA PNEUMOPHILA
SENSITIVITY
AMOEBA
COOLING TOWERS
INFECTIOUS DISEASES
ANIMALS
ANTI-INFECTIVE AGENTS
BACTERIA
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DRUGS
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PROTOZOA
SARCODINA
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