HHS Public Access Author manuscript Author Manuscript
JAMA Intern Med. Author manuscript; available in PMC 2017 June 01. Published in final edited form as: JAMA Intern Med. 2016 June 1; 176(6): 807–815. doi:10.1001/jamainternmed.2016.1500.
Environmental Contamination in the Home and Risk of Recurrent Community-Associated Methicillin-Resistant Staphylococcus aureus Infection
Author Manuscript
Justin Knox, MPH†,*, Sean B. Sullivan, MPH†, Julia Urena, BA†, Maureen Miller, PhD‡, Peter Vavagiakis, MS§, Qiuhu Shi, PhD∥, Anne-Catrin Uhlemann, MD PhD†, and Franklin D. Lowy, MD†,¶ †Division
of Infectious Diseases, Department of Medicine, Columbia University, College of Physicians & Surgeons, New York
‡Department §Panna
of Epidemiology, Mailman School of Public Health, Columbia University
Technologies, Inc., New York
∥Department
of Epidemiology and Community Health, School of Health Sciences and Practice, New York Medical College, New York ¶Department
of Pathology & Cell Biology, Columbia University, College of Physicians & Surgeons,
New York
Author Manuscript
Abstract Importance—Recently, it has been debated whether environmental contamination plays an important role in recurrent Staphylococcus aureus infections within households and thus requires different intervention strategies to prevent recurrent infections. Objective—To assess whether household environmental contamination increases the risk of recurrent infection among subjects with a community-associated methicillin-resistant S. aureus (MRSA) infection. Design—A cohort study was conducted between November 2011 and June 2014. Participants were followed for 6 months. Participants’ exposure status remained blind throughout the study. Setting—The Columbia University Medical Center catchment area.
Author Manuscript
Participants—All patients within 72 hours of presentation with positive MRSA cultures from skin and soft tissue infections, blood, urine or sputum specimens were identified. Two hundred sixty-two patients met study inclusion criteria and were recruited, 83 (32%) agreed to participate along with 214 household members. The majority of index cases were Hispanic and female. Sixtytwo (75%) households completed follow-up.
*
Corresponding author: Justin Knox ([email protected]), Columbia University Medical Center, Department of Medicine, Division of Infectious Diseases, 630 W 168th Street, New York, NY 10032, Phone: 212-305-5678, Fax: 212-305-5794. No authors have potential conflicts of interest to report. Conceived and designed the experiments: JK SBS MM ACU FDL. Performed the experiments: JK SS JU ACU FDL. Analyzed the data: JK SBS QS. Contributed reagents/materials/analysis tools: PV. Wrote the paper: JK MM ACU FDL. Designed software for data entry: PV. Written permission has been obtained from all persons named in the acknowledgment
Knox et al.
Page 2
Author Manuscript
Intervention(s) for Clinical Trials or Exposure(s) for observational studies— Concordant environmental contamination, defined as having an isolate with the identical spa and SCCmec type or antibiotype as the index patient’s clinical isolate, present on one or more environmental surfaces at the time of a home visit to the index after infection. Main Outcome(s) and Measure(s)—Index recurrent infection, defined as any self-reported infection among the index during follow-up.
Author Manuscript
Results—Most (80%) MRSA infections were due to the epidemic strain USA300. Thirty-five (43%) indexes reported a recurrent infection during follow-up; 13 (65%) from the 20 households with environmental contamination and 21 (34%) from the 62 households without (p=.02). The clinical isolate was present in the environment in 20 (24%) households and not found in 62 (76%) households. A significant minority (43%, n=35/82) of patients with a MRSA infection reported a recurrent infection during follow-up, many of which (43%, n=15/35) required hospital treatment. Environmental contamination was found to increase the rate of index recurrent infection (IRR: 2.05 [1.03–4.10] p=.04). Conclusions and Relevance—Household environmental contamination was associated with an increased rate of recurrent infection. Environmental decontamination should be considered as a strategy to prevent future MRSA infections, particularly among households where an infection has occurred.
Introduction
Author Manuscript
Over the past three decades, there has been a dramatic increase in the number of methicillinresistant Staphylococcus aureus (MRSA) infections in community settings.1 While mostly involving the skin and soft tissues, 5–10% of these infections have been life threatening.2 Studies have highlighted the household as the primary reservoir for S. aureus in the community.3–11 Reports have described how epidemic clones ‘ping pong’ among family members,12,13 resulting in high rates of recurrent infection. The events that follow an initial community-associated (CA)-MRSA infection in a household include an increase in: 1) MRSA colonization among other household members;7,14–21 2) contamination of environmental surfaces;3,4,8,21 and 3) the risk of infection among other household members.12,13,21–26
Author Manuscript
The role of the environment in S. aureus transmission and infections has been previously studied in the healthcare setting27,28 and in certain high-risk community settings, such as in injection drug using sites and prisons.29,30 Environmental contamination has been increasingly recognized for its possible role in S. aureus transmission and infection within households.3,4,6,8,21,31,32 The potential importance of environmental contamination in S. aureus infection is further supported by the mixed success of body-site decolonization interventions designed to prevent recurrent infections within the household, with recurrent infections often occurring despite best efforts.33–36 In the general patient population, the success of MRSA decolonization is highly variable (ranging from 23% to 96%).37 Alternatively, environmental contamination may simply be a surrogate marker of colonization of multiple body sites or more common among households with multiple infections because infected individuals are more likely to shed bacteria into their
JAMA Intern Med. Author manuscript; available in PMC 2017 June 01.
Knox et al.
Page 3
Author Manuscript
environment. We conducted a prospective cohort study designed to determine whether environmental contamination of the household increases the risk of recurrent infection among individuals with a CA-MRSA infection while accounting for competing risk factors.
Methods Ethics statement Written informed consent was obtained from each individual before participation. Parental consent was required for the participation of children
JAMA Intern Med. Author manuscript; available in PMC 2017 June 01. Published in final edited form as: JAMA Intern Med. 2016 June 1; 176(6): 807–815. doi:10.1001/jamainternmed.2016.1500.
Environmental Contamination in the Home and Risk of Recurrent Community-Associated Methicillin-Resistant Staphylococcus aureus Infection
Author Manuscript
Justin Knox, MPH†,*, Sean B. Sullivan, MPH†, Julia Urena, BA†, Maureen Miller, PhD‡, Peter Vavagiakis, MS§, Qiuhu Shi, PhD∥, Anne-Catrin Uhlemann, MD PhD†, and Franklin D. Lowy, MD†,¶ †Division
of Infectious Diseases, Department of Medicine, Columbia University, College of Physicians & Surgeons, New York
‡Department §Panna
of Epidemiology, Mailman School of Public Health, Columbia University
Technologies, Inc., New York
∥Department
of Epidemiology and Community Health, School of Health Sciences and Practice, New York Medical College, New York ¶Department
of Pathology & Cell Biology, Columbia University, College of Physicians & Surgeons,
New York
Author Manuscript
Abstract Importance—Recently, it has been debated whether environmental contamination plays an important role in recurrent Staphylococcus aureus infections within households and thus requires different intervention strategies to prevent recurrent infections. Objective—To assess whether household environmental contamination increases the risk of recurrent infection among subjects with a community-associated methicillin-resistant S. aureus (MRSA) infection. Design—A cohort study was conducted between November 2011 and June 2014. Participants were followed for 6 months. Participants’ exposure status remained blind throughout the study. Setting—The Columbia University Medical Center catchment area.
Author Manuscript
Participants—All patients within 72 hours of presentation with positive MRSA cultures from skin and soft tissue infections, blood, urine or sputum specimens were identified. Two hundred sixty-two patients met study inclusion criteria and were recruited, 83 (32%) agreed to participate along with 214 household members. The majority of index cases were Hispanic and female. Sixtytwo (75%) households completed follow-up.
*
Corresponding author: Justin Knox ([email protected]), Columbia University Medical Center, Department of Medicine, Division of Infectious Diseases, 630 W 168th Street, New York, NY 10032, Phone: 212-305-5678, Fax: 212-305-5794. No authors have potential conflicts of interest to report. Conceived and designed the experiments: JK SBS MM ACU FDL. Performed the experiments: JK SS JU ACU FDL. Analyzed the data: JK SBS QS. Contributed reagents/materials/analysis tools: PV. Wrote the paper: JK MM ACU FDL. Designed software for data entry: PV. Written permission has been obtained from all persons named in the acknowledgment
Knox et al.
Page 2
Author Manuscript
Intervention(s) for Clinical Trials or Exposure(s) for observational studies— Concordant environmental contamination, defined as having an isolate with the identical spa and SCCmec type or antibiotype as the index patient’s clinical isolate, present on one or more environmental surfaces at the time of a home visit to the index after infection. Main Outcome(s) and Measure(s)—Index recurrent infection, defined as any self-reported infection among the index during follow-up.
Author Manuscript
Results—Most (80%) MRSA infections were due to the epidemic strain USA300. Thirty-five (43%) indexes reported a recurrent infection during follow-up; 13 (65%) from the 20 households with environmental contamination and 21 (34%) from the 62 households without (p=.02). The clinical isolate was present in the environment in 20 (24%) households and not found in 62 (76%) households. A significant minority (43%, n=35/82) of patients with a MRSA infection reported a recurrent infection during follow-up, many of which (43%, n=15/35) required hospital treatment. Environmental contamination was found to increase the rate of index recurrent infection (IRR: 2.05 [1.03–4.10] p=.04). Conclusions and Relevance—Household environmental contamination was associated with an increased rate of recurrent infection. Environmental decontamination should be considered as a strategy to prevent future MRSA infections, particularly among households where an infection has occurred.
Introduction
Author Manuscript
Over the past three decades, there has been a dramatic increase in the number of methicillinresistant Staphylococcus aureus (MRSA) infections in community settings.1 While mostly involving the skin and soft tissues, 5–10% of these infections have been life threatening.2 Studies have highlighted the household as the primary reservoir for S. aureus in the community.3–11 Reports have described how epidemic clones ‘ping pong’ among family members,12,13 resulting in high rates of recurrent infection. The events that follow an initial community-associated (CA)-MRSA infection in a household include an increase in: 1) MRSA colonization among other household members;7,14–21 2) contamination of environmental surfaces;3,4,8,21 and 3) the risk of infection among other household members.12,13,21–26
Author Manuscript
The role of the environment in S. aureus transmission and infections has been previously studied in the healthcare setting27,28 and in certain high-risk community settings, such as in injection drug using sites and prisons.29,30 Environmental contamination has been increasingly recognized for its possible role in S. aureus transmission and infection within households.3,4,6,8,21,31,32 The potential importance of environmental contamination in S. aureus infection is further supported by the mixed success of body-site decolonization interventions designed to prevent recurrent infections within the household, with recurrent infections often occurring despite best efforts.33–36 In the general patient population, the success of MRSA decolonization is highly variable (ranging from 23% to 96%).37 Alternatively, environmental contamination may simply be a surrogate marker of colonization of multiple body sites or more common among households with multiple infections because infected individuals are more likely to shed bacteria into their
JAMA Intern Med. Author manuscript; available in PMC 2017 June 01.
Knox et al.
Page 3
Author Manuscript
environment. We conducted a prospective cohort study designed to determine whether environmental contamination of the household increases the risk of recurrent infection among individuals with a CA-MRSA infection while accounting for competing risk factors.
Methods Ethics statement Written informed consent was obtained from each individual before participation. Parental consent was required for the participation of children
