title: Nano-TiO2-based photocatalytic disinfection of environmental surfaces contaminated by meticillin-resistant Staphylococcus aureus.
abstract: BACKGROUND
  Traditional cleaning and disinfection methods are inefficient for complete decontamination of hospital surfaces from meticillin-resistant Staphylococcus aureus (MRSA). Additional methods, such as nano-TiO2-based photocatalytic disinfection (PCD), could be helpful.
  
  
  OBJECTIVE
  To evaluate anti-MRSA activity of PCD on polyvinyl chloride (PVC) surfaces in natural-like conditions.
  
  
  METHODS
  Two identical PVC surfaces were used, and nano-TiO2 was incorporated into one of them. The surfaces were contaminated with MRSA isolated from hospitalized patients using a mist sprayer to simulate the mode of environmental contamination caused by a carrier. MRSA cell density was assessed before contamination until 180min after contamination using Rodac plates. The differences between test and control surfaces in terms of MRSA density and log MRSA density reduction were assessed using parametric and non-parametric statistical tests. Five strains were tested, and each strain was tested five times.
  
  
  RESULTS
  The highest median MRSA densities [46.3 and 43.1 colony-forming units (cfu)/cm(2) for control and test surfaces, respectively] were detected 45min after contamination. Median MRSA densities 180min after contamination were 10.1 and 0.7cfu/cm(2) for control and test surfaces, respectively (P<0.01). Log MRSA density reduction attributable to PCD was 1.16logcfu/cm(2), corresponding to 93% reduction of the baseline MRSA contamination.
  
  
  CONCLUSIONS
  The disinfectant activity remained stable throughout the 25 testing occasions, despite between-test cleaning and disinfection. The anti-MRSA activity of PCD was compatible with the benchmark for surface hygiene in hospitals (<1cfu/cm(2)), but required 3h of exposure to photocatalysis. Thus, PCD could be considered for non-clinical surfaces. However, for clinical surfaces, PCD should be regarded as supplemental to conventional decontamination procedures, rather than an alternative.
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy. Electronic address: stefano.petti@uniroma1.it.
authors.forename: S
authors.initials: S
authors.lastname: Petti
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy.
authors.forename: G A
authors.initials: GA
authors.lastname: Messano
mesh_terms: D058491:Bacterial Load; D004202:Disinfectants / Q000494:pharmacology*; D004203:Disinfection / Q000379:methods*; D004783:Environmental Microbiology; D006761:Hospitals; D006801:Humans; D017053:Infection Control / Q000379:methods*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D013997:Time Factors; D014025:Titanium / Q000494:pharmacology*
chemical_list: D004202:Disinfectants; C009495:titanium dioxide; D014025:Titanium
keywords: Environmental contamination; Hospital surface; Meticillin-resistant Staphylococcus aureus (MRSA); Photocatalytic disinfection