Sources of Pathogens Causing Healthcare-Associated Infections

Transcription

1 The Role of the Environment in Transmission of Healthcare-Associated Infections, No-Touch Methods to Decontaminate the Environment, and When and How to Culture the Environment John M. Boyce, MD Director, Hospital Epidemiology & Infection Control Yale-New Haven Hospital and Clinical Professor of Medicine Yale University School of Medicine

2 Sources of Pathogens Causing Healthcare-Associated Infections Patients represent the major reservoir of healthcareassociated pathogens Environmental surfaces near patients colonized or infected with pathogens that survive in the environment are another source from which transmission can occur Less frequent sources include: Medical and surgical equipment Water Air

3 Evidence Supporting the Role of Contaminated Surfaces in Transmission of Healthcare-Associated Infections Surfaces in the rooms of colonized or infected patients frequently become contaminated with pathogens Pathogens can survive on hospital surfaces for days or weeks Healthcare personnel frequently contaminate their hands or gloves by touching contaminated objects in patient rooms The frequency of hand or glove contamination is related to the frequency with which surfaces in patient rooms are contaminated Weber DJ et al. Curr Opin Infect Dis 2013;26: Otter JA et al. Am J Infect Control 2013;41:S6-S11

4 Evidence Supporting the Role of Contaminated Surfaces in Transmission of Healthcare-Associated Infections A patient admitted to a room previously occupied by a patient with a pathogen is at increased risk of developing colonization or infection by the same pathogen Improved cleaning of surfaces in patient rooms can reduce the spread of healthcare-associated pathogens Improved terminal disinfection of rooms can reduce the risk of subsequent patients acquiring pathogens that colonized or infected the prior occupant of the room Weber DJ et al. Curr Opin Infect Dis 2013 Otter JA et al. Am J Infect Control 2013;41:S6-S11

5 Frequency of Clostridium difficile Environmental Contamination Clostridium difficile is the most common cause of antibiotic-associated diarrhea Patients with diarrhea caused by C.difficile contaminate environmental surfaces in their vicinity Percent of environmental cultures positive varies Rooms with no recent C.difficile patient: 2.6 8% (+) Rooms of patients with C.difficile in their bowel, but do not have diarrhea: 7 29% (+) Rooms of patients with C.difficile diarrhea: 20 90% (+) Fekety R et al. Am J Med 1981;70:906 McFarland L et al. NEJM 1989;320:204 Struelens MJ et al. Am J Med 1991;91 (Suppl 3B):138S Sethi AK et al. Infect Control Hosp Epidemiol 2010;31:21

6 Percent of Stool, Skin and Environmental Cultures Positive for Clostridium difficile at Various Times During the Illness Sethi AK et al. Infect Control Hosp Epidemiol 2010;31:21

7 Environmental Contamination by MRSA Percent of surfaces contaminated with MRSA varies among patients colonized or infected at different body sites 6% of surfaces when patient colonized in nose 36% of surfaces if MRSA in wound or urine 59% of surfaces if MRSA heavy GI colonization + diarrhea 19% of surfaces in an outpatient clinic were contaminated with community-acquired MRSA Boyce JM et al. ICHE 1997;18:622 Johnston C et al. ICHE 2006;27:1133 Boyce JM et al. ICHE 2007;28:1142

8 Environmental Contamination by Vancomycin-Resistant Enterococci (VRE) VRE are frequently present on the skin of patients who have VRE Patient with VRE shed the bacteria onto surfaces near them 7% to 46% of environmental surfaces in the rooms of patients who have VRE are contaminated with VRE Boyce JM et al. J Clin Microbiol 1994;32:1148 Bonten MJM et al. Lancet 1996;348:1615 Weber DJ et al. Infect Control Hosp Epidemiol 1997;18:306 Hayden MK et al. Infect Control Hosp Epidemiol 2008;29:149 VRE Cultured from a Bedside Rail

9 Environmental Contamination by Gram-Negative Rods Acinetobacter is the Gram-negative rod that is most likely to cause contamination of environmental surfaces In outbreak settings, from 3% to 50% of environmental surfaces cultured have been contaminated with Acinetobacter Carbapenem-resistant Enterobacteriaceae (CRE) such as Klebsiella, Enterobacter and Escherichia coli are less likely to cause environmental contamination CRE contaminated only 8% to 10% of surfaces in the rooms of patients who were colonized or infected with CRE in two studies Weber DJ et al. Am J Infect Control 2010;38:S25 Weber DJ et al. Infect Control Hosp Epidemiol 2015 (Ahead of print) Rock C et al. Infect Control Hosp Epidemiol 2014;35:426

10 Who Causes Greater Environmental Contamination - Colonized Patients or Infected Patients? 1023 environmental surfaces were cultured before terminal cleaning in 45 rooms of patients either colonized or infected with MRSA or VRE Rooms of colonized patients had higher median colony counts of target organisms than infected patients? Due to treatment of infected patients Colonized patients may have been less ill and moved about their room more frequently Room Contamination with MRSA or VRE Knelson LP et al. Infect Control Hosp Epidemiol 2014;35:872

11 Survival of Pathogens in the Environment Pathogens that survive well in the environment include MRSA, VRE, C. difficile, Acinetobacter and Norovirus Pathogen MRSA VRE Survival 2 to 9 weeks 1 to 12 weeks C. difficile spores Days to 5 months Acinetobacter Norovirus Carbapenem-resistant Gram-negative rods 3 to 33 days Hours to 12 days < 3 days (light inoculum) 20 days (heavy inoculum) Hota B et al. Clin Infect Dis 2004;39:1182 Kramer A et al. BMC Infect Dis 2006;6:130 Havill NL et al. Infect Control Hosp Epidemiol 2014;35:445 Weber DJ et al. Infect Control Hosp Epidemiol 2015 (Ahead of print)

12 Percentage of Positive Gloved Hand Imprint Cultures After Contact with Commonly Examined Skin Sites and Environmental Sites of 30 Patients with Clostridium difficile Guerrero DM et al. Amer J Infect Control 2012;40:556

13 Percent of Gloves Contaminated Frequency of Acquisition of MRSA on Gloved Hands After Contact with Patients and Environmental Surfaces Nurses were directly observed while caring for patients with MRSA in a wound or urine Cultures of gloved hands were obtained from: 12 nurses with direct patient contact 12 nurses who had no direct contact with patients, but touched environmental surfaces in patient rooms A second study found that 10% of HCWs had MRSA hand contamination after contact with the patients environment % 42% Direct Contact with Patient Contact only with Environment Boyce JM et al. Infect Control Hosp Epidemiol 1997;18:622 Creamer E et al. J Hosp Infect 2010;75:107

14 Frequency of Acquisition of MRSA on Gloved Hands After Contact with Skin and Environmental Surfaces Stiefel U et al. Infect Control Hosp Epidemiol 2011;32:185

15 Frequency of Hand/Glove Contamination is Related to Level of Environmental Contamination Environmental Sites Positive (%) # of Index C. difficile Cases with Environmental and Personnel Cultures / / /12 (8%) Samore M et al. Am J Med 1996;100:32 Boyce JM et al. Infect Control Hosp Epidemiol 1997;18:622 # of Personnel with Positive Hand Cultures/# Cultured >50 6 9/25 (36%) Gloves of 12 nurses who had no direct contact with MRSA patients, but touched environmental surfaces in patient rooms, were cultured 42% of nurses had contaminated their gloves with MRSA In 4/7 instances when gloves were negative, environmental surfaces in the patients rooms revealed little or no MRSA

16 Hand Hygiene After Touching Objects in Patient Rooms Touching environmental surfaces in rooms of colonized or infected patients frequently results in contamination of the hands or gloves of HCWs Both CDC and WHO hand hygiene guidelines recommend that hand hygiene be performed after touching patient surroundings Even if there was no direct contact with the patient Even if gloves were worn CDC Guideline for Hand Hygiene in Healthcare, 2002 WHO Guidelines on Hand Hygiene in Health Care, 2009

17 Routine Daily Cleaning of Patient Rooms is Essential Patients continuously shed pathogens such as MRSA, VRE, C. difficile or MDR Gram-negative rods from their skin and gastrointestinal tract onto surfaces around them After cleaning of a patient s room, surfaces become re-contaminated if the patient is still present Therefore, daily cleaning of patient rooms is indicated Selection of an effective surface disinfectant and correct application using an appropriate contact time are essential Rutala WA et al. Infect Control Hosp Epidemiol 2014;35:855

18 Reducing Environmental Contamination Reduces VRE Transmission Prospective, 9-month study in an MICU included Admission and daily screening of patients Environmental and HCW hand cultures twice weekly Study design included Baseline period (1) Education/monitoring/feedback for housekeepers (2) Wash-out period with no specific intervention (3) Multimodal hand hygiene intervention (4) Hayden MK et al. Clin Infect Dis 2006;42:1552

19 Reducing Environmental Contamination Reduces VRE Transmission Environmental cleaning rate increased significantly VRE environmental contamination decreased significantly Cleaning Rate vs VRE Acquisitions VRE acquisitions by patients decreased significantly Other factors analyzed could not explain decreased VRE acquisition rate Period Cleaning rate VRE acquisitions Hayden MK et al. Clin Infect Dis 2006;42:1552

20 Sequential Interventions to Improve C. difficile Disinfection of Patient Rooms Enhanced Daily Cleaning UV Light Device Used Sitzlar B et al. Infect Control Hosp Epidemiol 2013;34:459

21 Increased Risk from the Prior Room Occupant Multiple studies have shown that terminal (post-discharge) cleaning and disinfection of rooms of patients with pathogens such as VRE, MRSA or C. difficile is often suboptimal Pathogens remaining in patient rooms following terminal cleaning and disinfection can serve as a source of transmission to the next patient admitted to the room Several studies have documented the risk that the prior room occupant poses to patients subsequently admitted to the room Otter et al. Am J Infect Control 2013;41:S6-S11

22 Increased Risk from the Prior Room Occupant Huang MRSA Huang VRE Nseir P. aeruginosa Drees VRE (2 weeks) Drees VRE Shaughnessy C. difficile Nseir A. baumannii Odds ratio (Increased chances of acquiring pathogen) Otter et al. Am J Infect Control 2013;41:S6-S11

23 Improved Terminal Disinfection of Rooms Can Reduce Transmission of Pathogens 30-month prospective study with 12-month pre-intervention phase and 18-month intervention on 6 high-risk units On 3 units, hydrogen peroxide vapor (HPV) was used to decontaminate the rooms of patients with MDROs after discharge Monthly environmental cultures for MDROs were obtained on all study units for 3 months before and for 6 months during intervention Risk of MDRO acquisition by patients admitted to rooms decontaminated using HPV was compared with rooms disinfected by standard methods Passaretti CL Clin Infect Dis 2013;56:27

24 Improved Terminal Disinfection of Rooms Can Reduce Transmission of Pathogens Patients admitted to rooms decontaminated with HPV were 64% less likely to acquire any MDRO, and 80% less likely to acquire VRE Risk of acquiring C. difficile, MRSA, and multidrug-resistant gramnegative rods individually was reduced, but not significantly Proportion of rooms environmentally contaminated with MDROs was reduced significantly on units where HPV was used, but not on non-hpv units Conclusion: HPV decontamination reduced environmental contamination and the risk of acquiring MDROs when compared to standard cleaning methods Passaretti CL Clin Infect Dis 2013;56:27

25 No-Touch Room Decontamination Methods In many facilities, < 50% of high-touch surfaces are wiped by housekeepers at the time of terminal room cleaning In response, no-touch automated systems have been developed to decontaminate patient rooms after discharge Examples include: Aerosolized hydrogen peroxide Hydrogen peroxide vapor systems Gaseous ozone Saturated steam systems Mobile ultraviolet and pulsed-xenon light devices Carling PC et al. Am J Infect Control 2010;38 (5 Suppl 1):S41 Otter JA et al. J Hosp Infect 2013;83:1

26 Aerosolized Hydrogen Peroxide Dry Mist Systems Aerosols contain particles microns 5% - 6% hydrogen peroxide and < 50 ppm silver ions Generally reduces indicator spores by < 4 logs Have significantly reduced bacterial counts in laboratory settings and patient care areas No data on impact on epidemic or endemic infection rates Less effective than hydrogen peroxide vapor Andersen BM et al. J Hosp Infect 2006;62:149 Shapey S et al. J Hosp Infect 2008;70:136 Bartels MD et al. J Hosp Infect 2008;70:35 Barbut F et al. Infect Control Hosp Epidemiol 2009;30:515 Piskin N et al. Am J Infect Control 2011;39:757 Fu TY et al. J Hosp Infect 2012;80:199

27 Hydrogen Peroxide Vapor 2 main hydrogen peroxide vapor technologies are commercially available Micro-condensation process Dry gas process Despite differences in method of application, both technologies have been validated as effective Most experience in healthcare settings is with the micro-condensation process McAnoy AM: Vaporous Decontamination Methods, Australian Government DSTO 2006 Fisher J et al. Pharmaceutical Technology 2004, pg. 68 Pottage T et al. J Hosp Infect 2010;74:55

28 Vapor-Based Hydrogen Peroxide Systems Dry gas vaporized hydrogen peroxide (VHP) system has been shown to be effective against Mycobacterium tuberculosis, Mycoplasma, Acinetobacter, Clostridium difficile Bacillus anthracis, viruses, prions Dry gas VHP system contributed to control of Acinetobacter infections in an LTAC Used to removed environmental reservoirs during two outbreaks of Acinetobacter Fichet G et al. Lancet 2004;364:521 Heckert RA Appl Environ Microbiol 1997;63:3916 Rogers JV et al. J Appl Microbiol 2005;99:739 Pottage T et al. J Hosp Infect 2010;74:55 Ray A et al. Infect Control Hosp Epidemiol 2010;31:1236 Galvin S et al. J Hosp Infect 2012;80:67 Chmielarczyk A et al. J Hosp Infect 2012;81:239

29 Vapor-Based Hydrogen Peroxide Systems Micro-condensation HPV system is effective in eradicating important pathogens Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), C. difficile, Klebsiella, Acinetobacter, Serratia Mycobacterium tuberculosis, fungi, viruses Laboratory & in-hospital studies document 6 log 10 reductions of many pathogens, on both porous and non-porous surfaces French GL et al. J Hosp Infect 2004;57:31 Bates CJ et al. J Hosp Infect 2005;61:364 Hall L et al. J Clin Microbiol 2007;45:810 Otter JA et al. J Hosp Infect 2007;67:182 Hall L et al. Med Mycol 2008;46:189 Boyce JM et al. Infect Control Hosp Epidemiol 2008;29:723 Otter JA et al. J Clin Microbiol 2009;47:205 Pottage T et al. J Hosp Infect 2010;24:55 Lemmen S et al. Am J Infect Control 2015;43:82

30 Impact of Micro-condensation HPV System on Healthcare-Associated Infections Several non-randomized studies have reported that the micro-condensation HPV process has Significantly reduced room sites positive for Acinetobacter and MRSA in one hospital Contributed to control of outbreaks caused by MRSA, Serratia, C. difficile, and Acinetobacter Used to decontaminate rooms of patients with Lassa fever or Ebola Combined with multiple other measures against MDR Klebsiella Contributed to reduction of C.difficile cases Bates CJ et al. J Hosp Infect 2005;61:364 Jeanes A et al. J Hosp Infect 2005;61:85 Boyce JM et al. Infect Control Hosp Epidemiol 2008;29:723 Otter JA et al. J Hosp Infect 2010;75:325 Otter JA et al. Am J Infect Control 2010;38:754 Manian F et al. Infect Control Hosp Epidemiol 2011;32:667 Snitkin ES et al. Sci Transl Med 2012;4:148ra116 Manian F et al. Am J Infect Control 2013;41:537

31 Concerns Regarding Vapor-Based Hydrogen Peroxide Systems Need to seal air vents and doors increases cycle times Total cycle times (room prep/decontamination/breakdown) Micro-condensation process: hrs Dry Gas process: 8 hrs Micro-condensation HPV process is feasible in hospitals with high census levels Level of training and expertise of operators is greater than with other no-touch systems such as mobile UV-C light units No randomized, controlled trials of impact on infection rates Otter JA et al. Infect Control Hosp Epidemiol 2009;30:574 Ray A et al. Infect Control Hosp Epidemiol 2010;31:1236

32 Mobile Ultraviolet Light Systems Mobile UV light units that emit UV-C (254 nm range) can be used to decontaminate patient rooms after terminal cleaning Some units can be set to use short cycle times to kill vegetative bacteria or longer cycle times to kill spores Several systems have been shown by independent investigators to significantly reduce bacterial counts in patient rooms Easy to use, minimal training needed Nerandzic MM et al. BMC Infect Dis 2010;10:197 Rutala WA et al. Infect Control Hosp Epidemiol 2010;31:1025 Boyce JM et al. Infect Control Hosp Epidemiol 2011;32:737 Anderson DJ et al. Infect Control Hosp Epidemiol 2013;34:466 Mahida N et al. J Hosp Infect 2013;84:332 Zhang A et al. Infect Control Hosp Epidemiol 2013;34:1106 Nerandzic MM et al. PLoS One 2014;9:e107444

33 Mobile Ultraviolet Light Systems Studies have been conducted using different cycle times, and with inoculated carriers located at various distances from UV-C devices Pathogen Log10 Reductions (Direct Line of Sight) MRSA > 2 4 VRE > 3 5 MDR Acinetobacter 3 4 C. Difficile > 2-3 Log reductions achieved in shaded areas are generally < 1 log lower Nerandzic MM et al. BMC Infect Dis 2010;10:197 Rutala WA et al. Infect Control Hosp Epidemiol 2010;31:1025 Mahida N et al. J Hosp Infect 2013;84:332 Zhang A et al. Infect Control Hosp Epidemiol 2013;34:1106 Nerandzic MM et al. PLoS One 2014;9:e Rutala WA et al. Infect Control Hosp Epidemiol 2014;35:1070

34 Impact of Distance and Shading on Log 10 Reduction of Pathogens Device A Device B

35 Impact of UV-C Dosage on Log10 Reduction of Pathogens by Two UV-C Devices Device A Device B Nerandzic MM et al. PLoS One 2014;9:e107444

36 Ease of use Issues to Address When Considering Mobile Ultraviolet Light Systems Duration of cycle times recommended by manufacturer Evidence of microbiological efficacy published by independent investigators Cost per device Cost of replacement bulbs/service contracts Availability of digital recording, storage & retrieval of data

37 Pulsed-Xenon UV Light System Emits pulses of broad-spectrum light, including UV ( nm) and visible ( nm) light Device Pathogen Log 10 Reduction Per cm 2 Pulsed-Xenon UV C. difficile 0.55 MRSA 1.85 VRE 0.6 Continuous UV-C C. difficile 1.0 MRSA ~3.1 VRE ~3.6 Nerandzic MM Infect Control Hosp Epidemiol 2015;36:192 Several studies have shown significant reduction of pathogens in patient rooms using pulsed-xenon UV light device Stibich M et al. Infect Control Hosp Epidemiol 2011;32:286 Jinadatha C et al. BMC Infect Dis 2014;14:187 Ghantoji SS et al. J Med Microbiol 2015;64:191

38 Concerns Regarding Mobile UV-C and Pulsed Xenon Room Decontamination Devices Few, well-designed studies of the impact of systems on healthcare-associated infection rates Multicenter study of continuous UV-C device has been completed; results expected later this year Number of systems currently being marketed, often with limited documentation of effectiveness, makes choice of device difficult There are substantial differences between systems regarding Recommended cycle times Up-front and maintenance costs Odor generated by use of UV-C devices is initially of concern to some healthcare workers To date, no evidence that odor is harmful

39 Hydrogen Peroxide Vapor vs Ultraviolet Light Systems Choice between hydrogen peroxide vapor and ultraviolet light systems will depend on a number of factors, including its intended use and practicalities of application Variable Continuous UV-C or Pulsed-Xenon UV Hydrogen Peroxide Vapor Intended use Level of efficacy needed Decontaminate a relatively large proportion of rooms Significant reduction of pathogens Decontaminate primarily rooms with difficult-tokill or highly virulent pathogens Near-total or total eradication of pathogen Cycle times 15 min 45 min hrs Havill NL et al. Infect Control Hosp Epidemiol 2012;33:507 Otter JA et al. J Hosp Infect 2013;83:1

40 When to Culture the Hospital Environment Do not conduct random, undirected microbiologic sampling of air, water and environmental surfaces in healthcare facilities When indicated, conduct microbiologic sampling as part of an epidemiologic investigation or during assessment of hazardous environmental conditions to detect contamination or verify abatement of a hazard Limit microbiologic sampling for quality assurance purposes to Biologic monitoring of sterilization processes Monthly cultures of water and dialysate in hemodialysis units Short-term evaluation of the impact of infection control measures or changes in infection control protocols CDC Guidelines for Environmental Infection Control, 2003

41 Major Methods for Culturing Environmental Surfaces Method Moistened swab (direct inoculation onto solid media +/- broth enrichment) Moistened sponge & rinse Moistened wipe & rinse Direct immersion Contact (RODAC*) agar plates Membrane filtration of liquids Type of Objects Sampled Irregular objects, instruments Large flat surfaces Large, flat surfaces Immerse small objects in broth Fluids, water, instruments Flat surfaces Pass liquid specimens through membrane filter, then culture filter * RODAC: Replicate organism direct agar contact (or replicate organism detection and counting) CDC Guidelines for Environmental Infection Control, 2003 Clinical Microbiology Procedures Handbook, eds: Garcia LS & Isenberg HD, ASM Press 2011

42 Direct Plating of Swabs vs Broth Enrichment for Culturing Environmental Surfaces Bedside rail BP cuff TV remote Table Toilet seat Dresser Toilet rail Door Nurse call button IV pump Percent of sites contaminated with MRSA Direct Plating Broth Enrichment Verity P et al. J Hosp Infect 2001;49:204 Mayer RA et al. Am J Infect Control 2003;31:221 Duckro AN et al. Arch Intern Med 2005;165:302 Otter JA et al. J Hosp Infect 2007;67:182

43 Wipe-Rinse Method Useful for culturing large, flat, nonabsorbent surfaces Small (e.g., 2 cm x 2 cm) pre-moistened gauze pads or wipes are used to sample surface. Wipes are placed in broth (with or without vortexing) and incubated x hrs, then subcultured to solid agar Wipes are most likely more sensitive than swab or RODAC cultures due to larger area sampled and use of broth enrichment. Can provide either qualitative or quantitative results Not used as frequently as swab or RODAC methods Al-Hamad A et al. J Hosp Infect 2008;70:328 Sethi AK et al. ICHE 2010;31:21 Attaway HH et al. Am J Infect Control 2012;40:907 Sitzlar B et al. ICHE 2013;34:459

44 Culturing Surfaces to Detect Bacteria on Environmental Surfaces Specialized agar culture plates can be used to detect how many bacteria are on surfaces E.g., Dey-Engley neutralizing agar The agar plate is pressed against a surface, and then incubated in the laboratory for 48 hours RODAC agar plate for culturing surfaces The plate is then examined visually and the number of colonies of bacteria growing on agar plate are counted Yields quantitative results (CFU/cm 2 ) Example use: periodic monitoring the adequacy of cleaning and disinfection practices Bacterial colonies growing on RODAC plate

45 Membrane Filtration Cultures for Water or Other Liquid Samples Moderate to large volumes of water, liquid medications, or rinses from equipment channels should be cultured using membrane filtration methods Especially important if low-level bacterial contamination is likely Fluids are put through sterile funnel with 0.22 µm or 0.45 µm filter using vacuum apparatus; filters are placed on agar plates and incubated x 48 hr Example uses: sampling water fountains, liquid medications, and fluid rinsed through contaminated bronchoscopes Weber DJ et al. Am J Infect Control 1999;27:59 Srinivasan A et al. N Engl J Med 2003;348:221 Blossom DB et al. Arch Intern Med 2009;169:1705 Palamore TN et al. ICHE 2009;30:764 Haupt TE et al. ICHE 2012;33:185

46 Membrane Filtration Cultures for Water or Other Liquid Samples Culture from water fountain Fluid culture from bronchoscope

47 Summary Substantial evidence supports the role of contaminated environmental surfaces in transmission of healthcareassociated pathogens Manual cleaning/disinfection of environmental surfaces using an approved disinfectant and adequate contact times are essential to reduce transmission Newer automated no-touch decontamination systems can complement manual cleaning/disinfection practices Culturing the inanimate environment should be limited to indications recommended in CDC environmental guideline

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