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Multidrug-resistant organisms contaminating supply carts of contact isolation patients
American Journal of Infection Control 42 (2014) 1124-6
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Brief report
Multidrug-resistant organisms contaminating supply carts of contact isolation patients Shane Zelencik MPH, CIC a, *, Donna Schora MT (ASCP) b, Adrienne Fisher MT (ASCP), CIC a, Corrinna Brudner BSc, CPHI(C), CIC a, Parul Patel MT (ASCP) b, Ari Robicsek MD a, Becky Smith MD a, Lance R. Peterson MD a, b, Marc-Oliver Wright MT (ASCP), MS, CIC a a b
Department of Infection Control, NorthShore University HealthSystem, Evanston, IL Infection Control Research Laboratory, NorthShore University HealthSystem, Evanston, IL
Key Words: Intensive care unit Environmental cleaning Contaminated supplies
Contamination of supply carts stored within rooms of patients on contact isolation for multidrugresistant organisms was assessed. Despite the presence of environmentally persistent organisms, very little contamination occurred to these carts or the supplies stored within them. A single isolate containing a multidrug-resistant Acinetobacter baumannii was isolated, representing 1.3% of the 80 swabs collected. Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Pathogenic multidrug-resistant (MDR) organisms (MDROs) persist in the patient care environment.1-4 Many gram-positive bacteria can survive for months on surfaces under ideal conditions.1 Transfer of organisms from the environment to the hands and gloves of health care personnel (HCP) has been documented,5 and the hands of HCP can transfer organisms to environmental surfaces and clean patient sites.6 These transfers create a plausible chain of infection, which can lead to transmission of MDROs to subsequent room occupants.7 The capability of enclosed/covered supplies in patient rooms to act as vectors in transmitting pathogenic MDROs from one patient to the next remains unknown. This study assessed the probability that carts stored in intensive care unit (ICU) patient rooms represent a source of MDRO transmission. METHODS This study was performed in 4 medical/surgical ICUs within a 900-bed multihospital health care system. Locked supply carts containing items used for routine patient care (Fig 2) remain in patient rooms for the duration of the ICU stay. Supply carts (nurse servers) for patients on contact isolation for colonization/infection * Address correspondence to Shane Zelencik, MPH, CIC, 2650 Ridge Ave, Suite 124 Burch, Evanston, IL 60201. E-mail address: [email protected] (S. Zelencik). Conflict of interest: None to report.
Fig 1. Frequencies of MDROs colonizing or infecting ICU patients, which resulted in those patients being on contact precautions. Each bar represents the number of instances a patient was isolated for the presence of a specific MDRO.
with an MDRO hospitalized for at least 3 days were selected for screening. Nurse servers were sampled with a double-headed BBL Culture Swab (BD Diagnostic Systems, Sparks, MD) premoistened with transport medium. Two swabs were obtained, 1 from the cart’s contents and 1 from the external drawer pulls and internal drawer surfaces. Each sample was plated to selective media: BBL CHROMAgar
0196-6553/$36.00 - Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajic.2014.06.009
S. Zelencik et al. / American Journal of Infection Control 42 (2014) 1124-6
1125
Fig 2. Standard list of supplies stored within the nurse servers in each ICU patient room.
MRSA II (BD Diagnostic Systems) for methicillin-resistant Staphylococcus aureus (MRSA) and VACC agar (Remel, Lenexa, KS) for vancomycin-resistant Enterococcus spp (VRE), extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, drug-resistant Acinetobacter spp, and drug-resistant Pseudomonas spp. For Clostridium difficile, the swabs were first plated to PRAS-Cycloserine Cefoxitin Fructose Agar with Horse Blood and Tarocholate (Anaerobe Systems, Morgan Hill, CA), then submerged into BBL Chopped Meat Glucose Broth, Prereduced II (BD Diagnostic Systems). Media were incubated in accordance with the manufacturers’ recommendations. After 48 hours, the Chopped Meat broth was subcultured to an additional cycloserine cefoxitin fructose agar (Anaerobe Systems) and held for 5 days. Organisms found on any plate were identified according to traditional clinical microbiology methods. When the same organism was isolated from a patient’s clinical isolate or screening culture and from the nurse server, restriction enzyme analysis (Pvu II) was performed to determine genetic relatedness. The collection and culture methodologies were validated under simulated real-world conditions. The surfaces and supplies of 4 stocked supply drawers were inoculated with a 0.5 McFarland standard suspension containing MDR streptococci (MRSA and VRE), MDR A baumannii, ESBL E coli, or C difficile. After 1 hour of drying, samples were collected and cultured as described above. A Wilson score interval was used to calculate the confidence intervals for the proportion of positive cultures among total cultures. RESULTS All of the validation culture results were positive for the organism of interest with recovery ranging from 2 colonies for C difficile to too many colonies to count for VRE. Samples from 40 patient rooms were collected, a total of 80 swabs. Fig 1 shows the relative frequency of various MDROs colonizing or infecting our ICU patients. A single isolate containing MDR A baumannii was obtained from the supplies within a nurse server. This finding constitutes 2.5% (95% CI, 0.4%-12.9%) of the cultures obtained from supplies only, and approximately 1.3% (95% CI, 0.2%-6.8%) of the total swabs. The subsequent restriction enzyme analysis indicated that the organism was genetically identical to the A baumannii cultured from the current patient.
contamination. The investigated supply carts are stored opposite patient beds, providing a spatial separation from the patients and their immediate care environments. These carts are equipped with coded locks that prevent the entry of patients and visitors, a feature that may provide protection from contamination. Routine environmental cleaning may have a protective effect as well. Staff interviews indicated that although the interior surfaces are cleaned as necessary, the external surfaces are cleaned daily using an appropriate hospital-grade disinfectant. Routine and consistent environmental cleaning methods have been shown to reduce the bioburden in patient care areas,8 and may help reduce the acquisition of MDROs.9 The clinical staff also may contribute to the lack of contamination via optimal workflows and hand hygiene compliance. ICU staff members regularly prepare supplies from the nurse server before patient contact, touching environmental surfaces, or starting a procedure, and they use the time to communicate with patients and family members. However, in the rare instances when a clinical staff member reenters a supply cart, she or he may not perform hand hygiene, which might have contributed to the single instance of contamination by A baumannii. A baumannii has been found to frequently contaminate gloves, gowns, and hands of HCP10 and has shown prolonged persistence in the environment.1 This study has several limitations. The small sample size makes extrapolating broad conclusions from the data challenging. In addition, the study did not differentiate between colonized and infected patients. Room selection was based on the presence of the organism, and patients with active infections may shed larger volumes of organisms that persist in the environment. Finally, samples were not obtained at discharge; however, they were obtained 3 days into the ICU stay, and because the average length of ICU stay is 4 days, samples were obtained toward the end of the average patient’s ICU stay. Despite these limitations, our data suggest that supplies stored in enclosed carts in rooms housing patients on contact isolation are infrequently contaminated with MDROs. More work is needed to assess the risks and benefits of retaining these supplies between patients. Acknowledgment Special thanks to Maureen Harazin for molecular typing, and the Infection Contol team.
DISCUSSION Our results suggest that although the overall patient environment routinely becomes contaminated with potentially pathogenic organisms,1-4 numerous factors may affect the level of
References 1. Kramer A, Schwebke I, Kampf G. How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect Dis 2006;6:130.
1126
S. Zelencik et al. / American Journal of Infection Control 42 (2014) 1124-6
2. Noskin GA, Bednarz P, Suriano T, Reiner S, Peterson LR. Persistent contamination of fabric-covered furniture by vancomycin-resistant enterococci: implications for upholstery selection in hospitals. Am J Infect Control 2000;28:311-3. 3. Boyce JM. Environmental contamination makes an important contribution to hospital infection. J Hosp Infect 2007;65(Suppl 2):50-4. 4. Weber DJ, Rutala WA, Miller MB, Huslage K, Sickbert-Bennett E. Role of hospital surfaces in the transmission of emerging health care-associated pathogens: norovirus, Clostridium difficile, and Acinetobacter species. Am J Infect Control 2010;38:S25-33. 5. Hayden MK, Blom DW, Lyle EA, Moore CG, Weinstein RA. Risk of hand or glove contamination after contact with patients colonized with vancomycin-resistant Enterococcus or the colonized patients’ environment. Infect Control Hosp Epidemiol 2008;29:149-54. 6. Duckro AN, Blom DW, Lyle EA, Weinstein RA, Hayden MK. Transfer of vancomycinresistant enterococci via health care worker hands. Arch Intern Med 2005;165:302-7.
7. Huang SS, Datta R, Platt R. Risk of acquiring antibiotic-resistant bacteria from prior room occupants. Arch Intern Med 2006;166:1945-51. 8. Goodman ER, Platt R, Bass R, Onderdonk AB, Yokoe DS, Hauang SS. Impact of an environmental cleaning intervention on the presence of methicillinresistant Staphylococcus aureus and vancomycin-resistant enterococci on surfaces in intensive care unit rooms. Infect Control Hosp Epidemiol 2008; 29:593-9. 9. Hayden MK, Bonten MJ, Blom DW, Lyle EA, van de Vijver DA, Weinstein RA. Reduction in acquisition of vancomycin-resistant Enterococcus after enforcement of routine environmental cleaning measures. Clin Infect Dis 2006;42: 1552-60. 10. Morgan DJ, Liang SY, Smith CL, Johnson JK, Harris AD, Furuno JP, et al. Frequent multidrug-resistant Acinetobacter baumannii contamination of gloves, gowns, and hands of healthcare workers. Infect Control Hosp Epidemiol 2010;31:716-71.
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Brief report
Multidrug-resistant organisms contaminating supply carts of contact isolation patients Shane Zelencik MPH, CIC a, *, Donna Schora MT (ASCP) b, Adrienne Fisher MT (ASCP), CIC a, Corrinna Brudner BSc, CPHI(C), CIC a, Parul Patel MT (ASCP) b, Ari Robicsek MD a, Becky Smith MD a, Lance R. Peterson MD a, b, Marc-Oliver Wright MT (ASCP), MS, CIC a a b
Department of Infection Control, NorthShore University HealthSystem, Evanston, IL Infection Control Research Laboratory, NorthShore University HealthSystem, Evanston, IL
Key Words: Intensive care unit Environmental cleaning Contaminated supplies
Contamination of supply carts stored within rooms of patients on contact isolation for multidrugresistant organisms was assessed. Despite the presence of environmentally persistent organisms, very little contamination occurred to these carts or the supplies stored within them. A single isolate containing a multidrug-resistant Acinetobacter baumannii was isolated, representing 1.3% of the 80 swabs collected. Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Pathogenic multidrug-resistant (MDR) organisms (MDROs) persist in the patient care environment.1-4 Many gram-positive bacteria can survive for months on surfaces under ideal conditions.1 Transfer of organisms from the environment to the hands and gloves of health care personnel (HCP) has been documented,5 and the hands of HCP can transfer organisms to environmental surfaces and clean patient sites.6 These transfers create a plausible chain of infection, which can lead to transmission of MDROs to subsequent room occupants.7 The capability of enclosed/covered supplies in patient rooms to act as vectors in transmitting pathogenic MDROs from one patient to the next remains unknown. This study assessed the probability that carts stored in intensive care unit (ICU) patient rooms represent a source of MDRO transmission. METHODS This study was performed in 4 medical/surgical ICUs within a 900-bed multihospital health care system. Locked supply carts containing items used for routine patient care (Fig 2) remain in patient rooms for the duration of the ICU stay. Supply carts (nurse servers) for patients on contact isolation for colonization/infection * Address correspondence to Shane Zelencik, MPH, CIC, 2650 Ridge Ave, Suite 124 Burch, Evanston, IL 60201. E-mail address: [email protected] (S. Zelencik). Conflict of interest: None to report.
Fig 1. Frequencies of MDROs colonizing or infecting ICU patients, which resulted in those patients being on contact precautions. Each bar represents the number of instances a patient was isolated for the presence of a specific MDRO.
with an MDRO hospitalized for at least 3 days were selected for screening. Nurse servers were sampled with a double-headed BBL Culture Swab (BD Diagnostic Systems, Sparks, MD) premoistened with transport medium. Two swabs were obtained, 1 from the cart’s contents and 1 from the external drawer pulls and internal drawer surfaces. Each sample was plated to selective media: BBL CHROMAgar
0196-6553/$36.00 - Copyright Ó 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.ajic.2014.06.009
S. Zelencik et al. / American Journal of Infection Control 42 (2014) 1124-6
1125
Fig 2. Standard list of supplies stored within the nurse servers in each ICU patient room.
MRSA II (BD Diagnostic Systems) for methicillin-resistant Staphylococcus aureus (MRSA) and VACC agar (Remel, Lenexa, KS) for vancomycin-resistant Enterococcus spp (VRE), extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, drug-resistant Acinetobacter spp, and drug-resistant Pseudomonas spp. For Clostridium difficile, the swabs were first plated to PRAS-Cycloserine Cefoxitin Fructose Agar with Horse Blood and Tarocholate (Anaerobe Systems, Morgan Hill, CA), then submerged into BBL Chopped Meat Glucose Broth, Prereduced II (BD Diagnostic Systems). Media were incubated in accordance with the manufacturers’ recommendations. After 48 hours, the Chopped Meat broth was subcultured to an additional cycloserine cefoxitin fructose agar (Anaerobe Systems) and held for 5 days. Organisms found on any plate were identified according to traditional clinical microbiology methods. When the same organism was isolated from a patient’s clinical isolate or screening culture and from the nurse server, restriction enzyme analysis (Pvu II) was performed to determine genetic relatedness. The collection and culture methodologies were validated under simulated real-world conditions. The surfaces and supplies of 4 stocked supply drawers were inoculated with a 0.5 McFarland standard suspension containing MDR streptococci (MRSA and VRE), MDR A baumannii, ESBL E coli, or C difficile. After 1 hour of drying, samples were collected and cultured as described above. A Wilson score interval was used to calculate the confidence intervals for the proportion of positive cultures among total cultures. RESULTS All of the validation culture results were positive for the organism of interest with recovery ranging from 2 colonies for C difficile to too many colonies to count for VRE. Samples from 40 patient rooms were collected, a total of 80 swabs. Fig 1 shows the relative frequency of various MDROs colonizing or infecting our ICU patients. A single isolate containing MDR A baumannii was obtained from the supplies within a nurse server. This finding constitutes 2.5% (95% CI, 0.4%-12.9%) of the cultures obtained from supplies only, and approximately 1.3% (95% CI, 0.2%-6.8%) of the total swabs. The subsequent restriction enzyme analysis indicated that the organism was genetically identical to the A baumannii cultured from the current patient.
contamination. The investigated supply carts are stored opposite patient beds, providing a spatial separation from the patients and their immediate care environments. These carts are equipped with coded locks that prevent the entry of patients and visitors, a feature that may provide protection from contamination. Routine environmental cleaning may have a protective effect as well. Staff interviews indicated that although the interior surfaces are cleaned as necessary, the external surfaces are cleaned daily using an appropriate hospital-grade disinfectant. Routine and consistent environmental cleaning methods have been shown to reduce the bioburden in patient care areas,8 and may help reduce the acquisition of MDROs.9 The clinical staff also may contribute to the lack of contamination via optimal workflows and hand hygiene compliance. ICU staff members regularly prepare supplies from the nurse server before patient contact, touching environmental surfaces, or starting a procedure, and they use the time to communicate with patients and family members. However, in the rare instances when a clinical staff member reenters a supply cart, she or he may not perform hand hygiene, which might have contributed to the single instance of contamination by A baumannii. A baumannii has been found to frequently contaminate gloves, gowns, and hands of HCP10 and has shown prolonged persistence in the environment.1 This study has several limitations. The small sample size makes extrapolating broad conclusions from the data challenging. In addition, the study did not differentiate between colonized and infected patients. Room selection was based on the presence of the organism, and patients with active infections may shed larger volumes of organisms that persist in the environment. Finally, samples were not obtained at discharge; however, they were obtained 3 days into the ICU stay, and because the average length of ICU stay is 4 days, samples were obtained toward the end of the average patient’s ICU stay. Despite these limitations, our data suggest that supplies stored in enclosed carts in rooms housing patients on contact isolation are infrequently contaminated with MDROs. More work is needed to assess the risks and benefits of retaining these supplies between patients. Acknowledgment Special thanks to Maureen Harazin for molecular typing, and the Infection Contol team.
DISCUSSION Our results suggest that although the overall patient environment routinely becomes contaminated with potentially pathogenic organisms,1-4 numerous factors may affect the level of
References 1. Kramer A, Schwebke I, Kampf G. How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect Dis 2006;6:130.
1126
S. Zelencik et al. / American Journal of Infection Control 42 (2014) 1124-6
2. Noskin GA, Bednarz P, Suriano T, Reiner S, Peterson LR. Persistent contamination of fabric-covered furniture by vancomycin-resistant enterococci: implications for upholstery selection in hospitals. Am J Infect Control 2000;28:311-3. 3. Boyce JM. Environmental contamination makes an important contribution to hospital infection. J Hosp Infect 2007;65(Suppl 2):50-4. 4. Weber DJ, Rutala WA, Miller MB, Huslage K, Sickbert-Bennett E. Role of hospital surfaces in the transmission of emerging health care-associated pathogens: norovirus, Clostridium difficile, and Acinetobacter species. Am J Infect Control 2010;38:S25-33. 5. Hayden MK, Blom DW, Lyle EA, Moore CG, Weinstein RA. Risk of hand or glove contamination after contact with patients colonized with vancomycin-resistant Enterococcus or the colonized patients’ environment. Infect Control Hosp Epidemiol 2008;29:149-54. 6. Duckro AN, Blom DW, Lyle EA, Weinstein RA, Hayden MK. Transfer of vancomycinresistant enterococci via health care worker hands. Arch Intern Med 2005;165:302-7.
7. Huang SS, Datta R, Platt R. Risk of acquiring antibiotic-resistant bacteria from prior room occupants. Arch Intern Med 2006;166:1945-51. 8. Goodman ER, Platt R, Bass R, Onderdonk AB, Yokoe DS, Hauang SS. Impact of an environmental cleaning intervention on the presence of methicillinresistant Staphylococcus aureus and vancomycin-resistant enterococci on surfaces in intensive care unit rooms. Infect Control Hosp Epidemiol 2008; 29:593-9. 9. Hayden MK, Bonten MJ, Blom DW, Lyle EA, van de Vijver DA, Weinstein RA. Reduction in acquisition of vancomycin-resistant Enterococcus after enforcement of routine environmental cleaning measures. Clin Infect Dis 2006;42: 1552-60. 10. Morgan DJ, Liang SY, Smith CL, Johnson JK, Harris AD, Furuno JP, et al. Frequent multidrug-resistant Acinetobacter baumannii contamination of gloves, gowns, and hands of healthcare workers. Infect Control Hosp Epidemiol 2010;31:716-71.