OBJECTIVETo evaluate ultraviolet C (UV-C) irradiance, UV-C dosage, and antimicrobial effect achieved by a mobile continuous UV-C device.DESIGNProspective observational study.METHODSWe used 6 UV light sensors to determine UV-C irradiance (W/cm2) and UV-C dosage (µWsec/cm2) at various distances from and orientations relative to the UV-C device during 5-minute and 15-minute cycles in an ICU room and a surgical ward room. In both rooms, stainless-steel disks inoculated with methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile spores were placed next to sensors, and UV-C dosages and log10 reductions of target organisms achieved during 5-minute and 15-minute cycles were determined. Mean irradiance and dosage readings were compared using ANOVA.RESULTSMean UV-C irradiance was nearly 1.0E-03 W/cm2 in direct sight at a distance of 1.3 m (4 ft) from the device but was 1.12E-05 W/cm2 on a horizontal surface in a shaded area 3.3 m (10 ft) from the device (P<.001). Mean UV-C dosages received by UV-C sensors located at different distances and orientation relative to the device varied significantly during 5-minute cycles and during 15-minute cycles (P<.001). Log10 reductions ranged from >4 to 1–3 for MRSA, >4 to 1–2 for VRE and >4 to 0 log10 for C. difficile spores, depending on the distance from, and orientation relative to, the device with 5-minute and 15-minute cycles.CONCLUSIONUV-C irradiance, dosage, and antimicrobial effect received from a mobile UV-C device varied substantially based on location in a room relative to the UV-C device.Infect Control Hosp Epidemiol 2016;37:667–672
Steam treatment is an effective disinfection method. Additional studies are needed to confirm whether these results are applicable to the clinical setting.
Outbreaks and pseudo-outbreaks of infection related to bronchoscopy typically involve Gram-negative bacteria, Mycobacterium species or Legionella species. We report an unusual bronchoscopy-related pseudo-outbreak due to Actinomyces graevenitzii. Extensive epidemiological and microbiological investigation failed to identify a common source. Strain typing revealed that the cluster was comprised of heterogeneous strains of A. graevenitzii. A change in laboratory procedures for Actinomyces cultures was coincident with the emergence of the pseudo-outbreak, and we determined that A. graevenitzii isolates more readily adopted a white, dry, molar tooth appearance on anaerobic colistin nalidixic acid (CNA) agar which likely facilitated its detection and identification in bronchoscopic specimens. This unusual pseudo-outbreak was related to frequent requests of bronchoscopists for Actinomyces cultures combined with a change in microbiology laboratory practices. Actinomyces graevenitzii is infrequently identified in clinical specimens, and its pathogenicity is not well defined. A. graevenitzii is a component of the oropharyngeal microbiota and has been reported to cause pneumonia, lung abscesses, osteitis of the jaw, and bacteremia (1-8). In early December 2013, an increase in the recovery of A. graevenitzii from specimens from patients who underwent bronchoscopy was noted by microbiology and infection control staff. Our investigation revealed that the cluster of A. graevenitzii isolates represented a pseudo-outbreak associated with a change in laboratory practices. MATERIALS AND METHODS Setting.A 1,500-bed tertiary care university-affiliated teaching hospital was the setting for this study.Epidemiological investigation. The microbiology laboratory's computerized database was queried to obtain the number of bronchoscopy cultures performed, the number of Actinomyces cultures ordered on bronchoscopy specimens, and the number of those cultures ordered that were positive for Actinomyces from January 2011 through December 2013. Medical records of patients whose bronchoscopy specimens yielded Actinomyces were reviewed, and the following variables were recorded: date of bronchoscopy, results of bronchoscopic specimen cultures for routine respiratory pathogens and for Actinomyces, bronchoscope used, bronchoscopist, endoscopy personnel involved in the procedure, procedure room number, and medications administered during bronchoscopy procedures. Only three bronchoscopes were routinely used, and almost all bronchoscopies were performed in procedure room 3. Therefore, we focused our investigation on room 3, the three bronchoscopes, and the "wash room" in which all bronchoscopes and endoscopes undergo highlevel disinfection using one of three automated endoscope reprocessors (AERs) (DSDs Medivators, Minneapolis, MN). Findings of cytologic examination and bronchial biopsy specimens were also recorded.Environmental sources of samples collected for culture in the endoscopy suite included unopened bottles of lidocaine, atomizer, cotton ball...
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