BACKGROUND: The development of portable steam generators has made disinfection of the environment more practical. This study assessed the "in vitro" ability of an overheated dry-saturated steam vapour system to kill multidrug and extensively-drug resistant nosocomial pathogens, defining the antimicrobial spectrum and the contact times compared with the activity of sodium hypochlorite. METHODS: The antibacterial efficacy of the overheated dry-saturated steam vapour system and of sodium hypochlorite against nosocomial pathogen isolates: extensively drug-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, carbapenemase-producing Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, high-level aminoglycoside-resistant Enterococcus faecalis, Candida parapsilosis and Aspergillus fumigatus were assessed using a surface time-kill test carried out on glass surfaces, with or without bovine serum albumin (BSA). RESULTS: The bactericidal activity of the overheated dry-saturated steam vapour system was observed at 180°C after 5min contact with or without BSA, using an initial inoculum of 10(9) CFU/mL. To reduce C. parapsilosis and A. fumigatus counts (from 10(7) CFU/mL), a longer contact time was necessary (7min). In vitro tests with sodium hypochlorite at 5% in the absence of an organic substance also resulted in an overall reduction in bacterial counts (from 10(9) CFU/mL) after 5min of treatment. For mycotic challenge (10(7) CFU/mL), a longer contact time was necessary (7min). In the presence of an organic substance, after 5min, the hypochlorite reduced the viable count from 10(9) to 10(5) CFU/mL for all bacterial strains except E. faecalis that showed a reduction of 2 log units (10(9) to 10(7) CFU/mL). For C. parapsilosis and A. fumigatus, a 2 log unit reduction was observed after 7min. CONCLUSIONS: Steam disinfection of environmental surfaces using a portable steam generator is a practical and effective method that is not affected by the presence of organic matter.

Effect of treatment with an overheated dry-saturated steam vapour disinfection system on multidrug and extensively drug-resistant nosocomial pathogens and comparison with sodium hypochlorite activity

BAGATTINI, MARIA;BELLOPEDE, ROSSELLA;GRIMALDI, NICOLA;NARDONE, Antonio;ZARRILLI, RAFFAELE;TRIASSI, MARIA
2015

Abstract

BACKGROUND: The development of portable steam generators has made disinfection of the environment more practical. This study assessed the "in vitro" ability of an overheated dry-saturated steam vapour system to kill multidrug and extensively-drug resistant nosocomial pathogens, defining the antimicrobial spectrum and the contact times compared with the activity of sodium hypochlorite. METHODS: The antibacterial efficacy of the overheated dry-saturated steam vapour system and of sodium hypochlorite against nosocomial pathogen isolates: extensively drug-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, carbapenemase-producing Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, high-level aminoglycoside-resistant Enterococcus faecalis, Candida parapsilosis and Aspergillus fumigatus were assessed using a surface time-kill test carried out on glass surfaces, with or without bovine serum albumin (BSA). RESULTS: The bactericidal activity of the overheated dry-saturated steam vapour system was observed at 180°C after 5min contact with or without BSA, using an initial inoculum of 10(9) CFU/mL. To reduce C. parapsilosis and A. fumigatus counts (from 10(7) CFU/mL), a longer contact time was necessary (7min). In vitro tests with sodium hypochlorite at 5% in the absence of an organic substance also resulted in an overall reduction in bacterial counts (from 10(9) CFU/mL) after 5min of treatment. For mycotic challenge (10(7) CFU/mL), a longer contact time was necessary (7min). In the presence of an organic substance, after 5min, the hypochlorite reduced the viable count from 10(9) to 10(5) CFU/mL for all bacterial strains except E. faecalis that showed a reduction of 2 log units (10(9) to 10(7) CFU/mL). For C. parapsilosis and A. fumigatus, a 2 log unit reduction was observed after 7min. CONCLUSIONS: Steam disinfection of environmental surfaces using a portable steam generator is a practical and effective method that is not affected by the presence of organic matter.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11588/612251
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