Abstract
Background
A history of methicillin-resistant Staphylococcus aureus (MRSA) is a determinant of inpatient bed assignment.
Methods
We assessed outcomes associated with rapid testing and discontinuation of MRSA Contact Precautions (CP) in a prospective cohort study of PCR-based screening in the Emergency Department (ED) of the Massachusetts General Hospital. Eligible patients had a history of MRSA and were assessed and enrolled if documented off antibiotics with activity against MRSA and screened for nasal colonization (subject-visit). PCR-negative subjects had CP discontinued; the primary outcome was CP-discontinuation. We identified semi-private rooms in which a bed was vacant due to the CP status of the study subject, calculated the hours of vacancy, and compared idle bed hours by PCR results. Program costs were compared to predicted revenue.
Results
There were 2,864 eligible patients; 648 (22.6%) subject-visits were enrolled. Of these, 65.1% (422/648) were PCR-negative and had CP discontinued. PCR-negative subjects had fewer idle bed hours compared to PCR-positive (28.6 ± 25.2 vs. 75.3 ± 70.5, p<0.001). The expected revenues from occupied idle beds and averted CP costs ranged from $214,160 to $268,340, and exceeded program costs.
Discussion
PCR-based screening for persistence of colonization effectively identified patients who cleared MRSA colonization.
Conclusion
A program of targeted screening for clearance of MRSA colonization resulted in expected revenues and decreased CP costs that outweighed programmatic costs.
Introduction
Despite a decline in infections due to methicillin-resistant Staphylococcus aureus (MRSA) nationally,1 there are a growing number of MRSA-colonized patients.2 Once individuals are identified as being colonized or infected with MRSA, the Centers for Disease Control and Prevention (CDC) recommends that such patients be placed in private rooms, or cohorted with other MRSA-colonized patients if private rooms are not available, and that Contact Precautions (CP) be implemented.3 Individuals can clear colonization spontaneously4–7and recent studies suggest the duration of colonization may be shorter than previously considered,8 but in the absence of national guidelines for CP-discontinuation,9 the pool of patients who have cleared colonization grows without a standardized approach for documenting clearance and discontinuing CP.
Effective and efficient strategies to identify patients who are no longer colonized are needed both to mitigate the clinical consequences of CP and the costs of inappropriate CP implementation, including the direct costs of CP (i.e., gowns, gloves, dedicated medical equipment) and increased provider time to comply with CP. Furthermore, patients requiring CP may adversely affect hospital revenues when CP results in decreased bed availability.
The effectiveness of any screening program aimed at identifying patients who have cleared colonization will depend on: timely identification of appropriate patients, test characteristics including turn-around time, and how quickly changes to infection control designation can be implemented. Rapid diagnostics using polymerase chain reaction (PCR) have demonstrated efficacy in reliable identification of patients who have cleared MRSA colonization.10 We report on a prospective study of outcomes among patients screened for persistent colonization prior to hospital admission with discontinuation of MRSA CP for those who were negative at screening.
Methods
Overview
The MRSA Ambulatory Pilot Project (MAPP) is a prospective cohort study of patients with a history of MRSA infection or colonization. Enrolled subjects had a commercial PCR screen to assess for persistent MRSA colonization. Those who were PCR-negative had MRSA CP discontinued.
Setting and study population
Patients with a history of a MRSA-positive isolate that was not more recent than 90 days at the time of a visit to the Massachusetts General Hospital (MGH) Emergency Department (ED) between 6/1/2012 and 12/31/2013 were eligible for the study. The program delivered text page alerts providing notification of patient eligibility 24 hours a day, 7 days a week to ED staff: from 6/1/2012–1/29/2013, alerts were delivered to the ED Triage Nurse and from 1/30/2013–12/31/2013, due to a change in work-flow, text page alerts were directed to an ED Clinical Research Coordinator (CRC) hired by the program to enroll subjects.
Enrollment required that an assessment screen be performed. Subjects were enrolled on this assessment screen if they reported no exposure to selected antibiotics with MRSA activity in the preceding 48 hours (later confirmed by chart review) and a nasal surveillance swab was obtained. Demographic, clinical and hospital operations data were collected, including age, gender, race, admission source, MRSA history, and for those admitted, length of stay (LOS). For admissions within 30 days of screening, room assignment was further identified as either an intensive care unit (ICU), which has exclusively private rooms, or non-ICU, which include a mix of semi-private and private rooms (approximately 60%:40%). Admitting location was identified as a private or semi-private room. Enrolled subjects screened as PCR-positive during the study who returned to the ED at least 90 days from the positive result were eligible for re-enrollment. Similarly, subjects excluded at one visit who later returned and met enrollment criteria were eligible for study entry at the later visit.
Screening procedure and laboratory methods
Specimens were collected with the Cepheid Collection Device (Copan, Murietta, GA) and processed using the Xpert MRSA® real-time PCR assay on the GeneXpert platform (Cepheid, Sunnyvale, CA).
Discontinuation of MRSA CP
PCR results were reviewed by trained staff who discontinued MRSA CP weekdays from 9am-5pm from 6/1/2012–1/30/2013, with expanded hours from 5pm–10pm between 2/1/2013–12/31/2013. While tests continued to be resulted overnight and on weekends, outside of staffed hours described, MRSA CP remained in effect until the next business day.
Primary outcome
The primary outcome was the proportion of enrolled subject-visits with CP-discontinuation. For those subject-visits resulting in admission, we also considered time-to-CP-discontinuation calculated as the time from specimen collection to CP-discontinuation. In cases in which the collection time was not documented, the time stamp reverted to arrival time in the microbiology laboratory.
Secondary outcomes
For enrolled subjects admitted within 30 days of the PCR screen, hours-to-bed arrival was designated as the time from arrival in the ED to inpatient bed arrival (inclusive of ED Observation bed arrival), using electronic time stamps for each event. Direct admissions that bypassed the ED were excluded from this calculation.
To examine the impact of discontinuation of MRSA CP on bed availability, we obtained hourly bed occupancy data from MGH Admitting Services, which included time stamps for bed occupancies and vacancies, and reasons for vacancy [i.e., need for MRSA, vancomycin-resistant enterococcus (VRE) or MRSA/VRE CP]. An internal audit was conducted comparing the reasons documented by Admitting Services to those documented by Infection Control staff. Concordance between the two groups was >85% for MRSA, VRE and combined MRSA and VRE.
When subjects were in semi-private rooms and the paired bed remained vacant as a result of CP, these beds were identified as “idle” beds and the number of idle bed hours attributed to the enrolled subject was determined. Not all admissions resulted in idle beds. The number and proportion of admissions with associated idle bed hours and the mean idle bed hours attributable for those admissions, are reported. Idle bed hours were summed across all three CP reasons due to the fact that removal of an MRSA flag from a VRE co-colonized subject would result in a transfer to the VRE-alone colonized pool. Admissions that occurred within 30 days of multiple screening visits for the same subject were assigned to the screening visit closest to the admission. This assignment only occurred when a subject was first documented on antibiotics and not enrolled, and on a subsequent visit was documented off antibiotics and enrolled, and had an admission within 30 days of both visits.
Program cost and revenue analysis
The costs of the screening program, costs of implementation of CP, and bed revenue were identified (Table 1). The direct costs of the screening program included tests and swabs (inclusive of tests performed as part of incorrect assessment) as well as personnel time, inclusive of staffing within the ED, Microbiology Laboratory and Infection Control Unit. Full time equivalent (FTE) portions were used, including salary and fringe benefits, based on data provided by MGH Human Resources.
Table 1.
Costs of screening program, costs of CP implementation per admission and revenues per occupied bed.
| Component costs of screening programa | |
| Materials (19 months) | |
| Tests ($42/cartridge) | $31,160 |
| Swabs ($0.70/swab) | $520 |
| Reimbursement ($52/test) | ($15,290) |
| Personnel | |
| Emergency department staff (0.3 FTE, 11 months) | $22,550 |
| Medical technologist staff (0.05 FTE, 19 months) | $3,840 |
| Program manager (0.5 FTE, 19 months) | $81,530 |
| Clinical manager (0.1 FTE, 19 months) | $31,130 |
| Sub-total, materials (net reimbursement) | $16,400 |
| Sub-total, personnel | $139,040 |
| Total Program Costs | $155,440 |
| Costs of CP implementation per admissionb | |
| PCR-negative subject | $20 |
| PCR-positive subject | $180 |
| Revenues per occupied bed (2012 $US)c | |
| Daily revenue | $1,900 |
CP: contact precautions; FTE: full time equivalent.
Costs for reagents and swabs were based on total screens and were offset by reimbursement by third-party payors; personnel costs were fixed for the program based on allocated FTEs and were calculated over the 19 months of the program. Total reimbursement was calculated by multiplying the mean reimbursement by the number of tests resulting in a line-level payment to the institution; tests that were eventually rolled into a lump-sum payment to the institution were not included.
Costs based on internal data provided by MGH Materials Management (gown: $0.30/use; gloves $0.08/pair; stethoscope: $3.41/item). Using estimates of the number of patient-provider interactions from Morgan, 2013, the total number of gowns and gloves per day were calculated. We assumed one stethoscope used per PCR-negative admission and two per PCR-positive admission. Daily costs of CP implementation were then multiplied by the mean length of stay for PCR-positive subjects to generate the per-admission costs of CP. PCR-negative patients CP costs were restricted to the mean time period prior to discontinuation of CP.
Mean net revenue per available bed calculated as follows: the mean case mix index-adjusted hospital price per patient-day for the median hospital in 2012 was discounted by the median hospital discount rate over the same time period, resulting in the mean daily revenue per occupied bed.
Calculations of direct expenditures for CP, inclusive of gowns, gloves and dedicated stethoscopes per admission, were based on internal data provided by MGH Materials Management. The number of each item used per admission was based on estimates from the literature.11
For PCR-negative subjects, the daily cost of CP was multiplied by the mean time to discontinuation of CP, divided by 24 hours, to account for the time during which the subject was still on MRSA CP. Once per-admission CP costs for PCR-negative and PCR-positive subjects were calculated, these costs were multiplied by the number of PCR-negative and PCR-positive admissions, respectively, to calculate the total cost of CP for the cohort. This approach allowed for the calculation of averted CP costs due to the program equal to the number of PCR-negative admissions multiplied by the difference in CP cost for PCR-positive and PCR-negative admissions.
To calculate the projected revenues from filling of idle beds due to reduction in MRSA colonized patients as part of the program, we first calculated the expected number of idle beds in the absence of the program as follows: we multiplied the observed proportion of admissions with idle beds in the PCR-positive group by the total number of admissions to approximate the number of admissions which would be associated with idle beds in the absence of any screening program. This calculation resulted in the number of admissions expected to have associated idle beds. This value was multiplied by the mean idle bed hours for PCR-positive subjects, divided by 24 hours to convert to idle bed days. Next, the idle bed hours in the PCR-negative subjects were similarly converted to idle bed days. The difference between the number of idle bed days in the absence of the program and the idle bed days observed in the PCR-negative group was considered the averted idle bed days due to the program. To account for the fact that discontinuation of MRSA CP does not always result in a previously idle bed being filled, we multiplied the resulting averted idle bed days due to the program by representative hospital occupancy levels ranging from 75%12 to 99% (mean occupancy for MGH is approximately 83%).
The mean net revenue per patient day was calculated using data from the Council of Teaching Hospital and Health Systems (COTH) as follows: the mean case mix index-adjusted hospital price per patient-day for the median hospital was discounted by the median hospital discount rate, resulting in the mean daily revenue per patient-day13. The mean net revenue per patient-day was multiplied by the number of occupied idle beds resulting in the expected net revenue across a range of occupancies.
The total projected revenue was calculated as the sum of revenue from occupied idle beds and averted CP costs. The projected program surplus was calculated as the net revenue minus costs of program implementation. These calculations were restricted to ED-based admissions within 30 days of the appropriate screen and did not account for future visits after that time frame.
Statistical Analysis
Demographic, clinical, and admission characteristics were compared using two-sided independent samples t-test or Chi-square test, as appropriate.
Human Subjects Research
The research presented was reviewed and approved by the Partners Human Research Committee (2011P001650).
Results
Subject eligibility and assessment
There were 2,864 subject-visits eligible for the screening program (Fig. 1). A large proportion of these (69.1%; 1,978/2,864) were never assessed for enrollment or assessment was performed incorrectly and thus were excluded from the study. Approximately a third of subject-visits assessed had documented concurrent antibiotic exposure and were excluded.
Figure 1. Subject Flow Diagram.
MRSA: methicillin-resistant staphylococcus aureus; NV: number of subject-visits; NS: number of subjects; NA: number of admissions within 30 days of screen. a Assessment not performed or performed incorrectly was categorized as: no antibiotic documentation, not swabbed (N=1,832); no antibiotic documentation and swabbed (N=61); documented on antibiotics and swabbed (N=11); documented off antibiotics and not swabbed (N=42); documented off antibiotics incorrectly and swabbed (N=22); or documented antibiotics incorrectly and not swabbed (N=10). b A subset of the number of subjects documented off antibiotics and screened by PCR were enrolled multiple times and found to be PCR-negative and PCR-positive during different enrollments (N=6).
Subject characteristics
Comparing enrolled subjects to patients who were never assessed or assessed incorrectly, there were no significant differences in age, gender, arrival source or time since most recent MRSA isolate (Table 2). Comparing enrolled subjects to subjects excluded because of antibiotic exposure, there were no significant differences in age or gender, but those documented on antibiotics were more likely to have arrived via transfer from another facility (p<0.001) and to have a more recent MRSA isolate (p=0.04). Among enrolled subjects, PCR-negative subjects tended to be younger, and had a longer elapsed time since both MRSA isolate and original colonization (p<0.001).
Table 2.
Demographic and clinical characteristics of subject-visits, by enrollment and exclusion status.
| Enrolled subjects-visits | Excluded subject-visits | |||||
|---|---|---|---|---|---|---|
| All enrolled (NV=648) |
MRSA PCR- negative (NV=422) |
MRSA PCR- positive (NV=226) |
Assessment not performed or performed incorrectly (NV=1,978)a |
Assessed on antibiotics, not swabbed (NV=238) |
||
| Age (mean ± SD) | 58 ± 19 | 55 ± 19 | 63 ± 19 | 57 ± 18 | 60 ± 17 | |
| Female Sex (No., %) | 255 (39.4) | 166 (39.3) | 89 (39.4) | 789 (39.9) | 102 (42.9) | |
| Race (No., %) | ||||||
| White | 512 (79.0) | 319 (75.6) | 193 (85.4) | 1,596 (80.7) | 196 (82.3) | |
| Black | 58 (9.0) | 39 (9.2) | 19 (8.4) | 192 (9.7) | 19 (8.0) | |
| Hispanic/Latino | 64 (9.9) | 53 (12.6) | 11 (4.9) | 134 (6.8) | 19 (8.0) | |
| Asian | 9 (1.4) | 7 (1.7) | 2 (0.9) | 31 (1.6) | 1 (0.4) | |
| Other | 5 (0.8) | 4 (0.9) | 1 (0.4) | 25 (1.3) | 3 (1.3) | |
| Arrival Source (No., %) | ||||||
| Walk In | 344 (53.1) | 244 (57.8) | 100 (44.2) | 990 (50.1) | 106 (44.5) | |
| EMS transport decision | 228 (35.2) | 128 (30.3) | 100 (44.2) | 702 (35.5) | 83 (34.9) | |
| Transfer from another facility | 71 (11.0) | 46 (10.9) | 25 (11.1) | 268 (13.5) | 48 (20.2) | |
| Other | 5 (0.8) | 4 (0.9) | 1 (0.4) | 18 (0.9) | 1 (0.4) | |
| MRSA history (mean ± SD) | ||||||
| Years from last positive MRSA isolate | 2.7 ± 2.6 | 3.4 ± 2.7 | 1.3 ± 1.6 | 2.7 ± 2.7 | 2.3 ± 2.5 | |
| Years from original MRSA documentation | 3.7 ± 3.0 | 4.2 ± 2.9 | 2.7 ± 2.8 | 3.7 ± 3.0 | 4.0 ± 3.3 | |
MRSA: methicillin-resistant Staphylococcus aureus; SD: standard deviation; EMS: emergency medical services. NV number of subject-visits
Assessment not performed or performed incorrectly was categorized as: no antibiotic documentation, not swabbed (N=1,832); no antibiotic documentation and swabbed (N=61); documented on antibiotics and swabbed (N=11); documented off antibiotics and not swabbed (N=42); documented off antibiotics incorrectly and swabbed (N=22); or documented antibiotics incorrectly and not swabbed (N=10).
CP-discontinuation
Among 648 subject-visits enrolled, 422 (65.1%) resulted in a negative PCR result and MRSA CP were discontinued. The mean time-to-CP discontinuation was 16.8 hours ± 20.1 (data not shown).
Admission characteristics and idle beds
A total of 476 admissions took place within 30 days of screening among enrolled subjects (Table 3). There were 291 PCR-negative admissions among 251 subjects, resulting in a mean of 1.2 ± 0.4 admissions per subject. Among the 185 PCR-positive admissions, 147 subjects had 1.3 ± 0.5 admissions. Mean length of stay (LOS) appeared shorter for PCR-negative admissions, but did not reach statistical significance (5.5 ± 6.6 days vs. 6.6 ± 7.4 days, p=0.09). Similar proportions of both groups were admitted to ICUs (6.9% vs. 8.6%, p=0.61). Private rooms were used less frequently for PCR-negative admissions (160/291 vs. 122/185, p=0.02). Mean hours-to-bed arrival did not differ by PCR result (9.1 ± 5.7 hours vs. 9.7 ± 6.4 hours, p=0.29). Forty-five (15.5%) PCR-negative admissions were associated with idle beds compared to 35 (18.9%) PCR-positive admissions (p=0.40). Mean idle bed-hours for PCR-negative admissions was 28.6 ± 25.2. Mean idle bed-hours was significantly higher for PCR-positive admissions (75.3 ± 70.5, p<0.001). Total idle bed-days for PCR-negative and PCR-positive admissions were 54 and 110, respectively.
Table 3.
Admission characteristics and idle beds, by assessment outcome.
| MRSA PCR- negative (NA=291) a |
MRSA PCR- positive (NA=185) |
|
|---|---|---|
| Admission Characteristics | ||
| Number of admissions per subject (mean ± SD) | 1.2 ± 0.4 | 1.3 ± 0.5 |
| LOS in days (mean ± SD) | 5.5 ± 6.6 | 6.6 ± 7.4 |
| LOS in days (median, IQR: 25th-75th) | 3.5 (1.3–6.3) | 4.5 (2.0–8.0) |
| Admission to ICU (No., % admissions) | 20 (6.9) | 16 (8.6) |
| Admission to private room (No., % admissions) | 160 (55.0) | 122 (65.9) |
| Hours-to-bed arrival (mean ± SD)† | 9.1 ± 5.7 | 9.7 ± 6.4 |
| Idle Beds | ||
| Admissions with idle beds attributed to MRSA, VRE or MRSA/VRE (No., %) | 45 (15.5) | 35 (18.9) |
| Idle bed hours attributable to MRSA, VRE or MRSA/VRE (mean ± SD) | 28.6 ± 25.2 | 75.3 ± 70.5 |
| Total idle bed days | 54 | 110 |
MRSA: methicillin-resistant Staphylococcus aureus; SD: standard deviation; LOS: length of stay; IQR: inter-quartile range; ICU: intensive care unit; VRE: vancomycin-resistant enterococcus.
NA number of admissions within 30 days of screen.
A subset of admissions were direct admissions in which patients were admitted directly to an inpatient bed, and thus had no recorded time to bed arrival. Among 291 PCR-negative admissions, 6 were direct admissions resulting in 285 admissions in the hours-to-bed arrival analysis.
Program cost and revenues
The costs of the program over the study totaled $155,440 (Table 4). The reduction in CP implementation costs attributable to discontinuation of MRSA CP in 291 PCR-negative admissions was $44,840. The predicted idle bed days in the absence of the program was [((291+185)×0.189)×(75.3/24)] = 282, resulting in an estimated available bed-days due to the program of 119. At occupancies ranging from 75–99%, this difference was estimated to result in 89 to 118 additional occupied beds, with additional expected revenues from filled idled beds ranging from $169,330 to $223,510. Combined additional revenues and averted CP costs from the program ranged from $214,160 to $268,340 and exceeded program cost at each level of occupancy (surplus range: $58,720 to $112,910).
Table 4.
Projected program finances, at varying hospital occupancy levels.
| Hospital occupancy level |
Occupied idle beds |
Program costsa |
CP costs avertedb |
Revenue from occupied idle beds |
Total revenue (occupied idle beds and CP costs averted) |
Projected program surplus |
|---|---|---|---|---|---|---|
| 75% | 89 | $155,440 | ($44,840) | ($169,330) | ($214,160) | ($58,720) |
| 80% | 95 | $155,440 | ($44,840) | ($180,610) | ($225,450) | ($70,010) |
| 85% | 101 | $155,440 | ($44,840) | ($191,900) | ($236,740) | ($81,300) |
| 99% | 118 | $155,440 | ($44,840) | ($223,510) | ($268,340) | ($112,910) |
CP: contact precautions
From Table 1.
CP costs did not vary by occupancy level because they reflect the reduction in implementation of CP among the PCR-negative admissions.
Discussion
Using MRSA history greater than 90 days and arrival in the ED as eligibility criteria, the majority of enrolled subjects were found, using a validated and highly sensitive assay, to no longer be colonized with MRSA. The frequency of CP-discontinuation among those screened by PCR was consistent with prior studies.5,7,8,10 We demonstrated the operational effectiveness of rapid screening for discontinuation of MRSA, a reduction in CP costs and increased availability of idle beds. Despite the initial investment to create targeted screening program, the estimated averted costs related to CP implementation and projected additional revenue from use of idle beds demonstrate the value of the program.
A growing body of evidence highlights the negative consequences of CP: longer waiting times for hospital bed assignment,14 decreased provider interactions,11 potentially more preventable adverse events and dissatisfaction with care,15,16 increased risks of inappropriate antibiotic use,17 and potential adverse psychological affects.18–20 These findings suggest that programs to accurately identify patients who are no longer colonized may improve patient care.
The main mechanism by which CP influenced bed availability was through the allocation of patients to semi-private rooms requiring two patients who have the same MRSA CP status. The efficiency of this allocation is dependent in part upon the relative proportions of non-colonized and colonized patients. In the absence of a suitable match, beds may remain vacant at a time when patients await admission or within-hospital transfer. By reducing the number of patients requiring MRSA CP, the pool of potential bed-matches is increased because the majority of patients require standard precautions.
There was no significant association observed between PCR results (negative or positive) and hours-to-bed arrival. PCR-positive admissions were, however, more frequently allocated to private rooms, which may attenuate any observed impact on hours-to-bed arrival. Delays to discontinuation of MRSA CP may have limited the impact because by the time CP-discontinuation occurred, the patient was already admitted to an inpatient unit. Results were not acted upon in the overnight hours and on the weekends, leading to potential missed opportunities to influence this metric. While allowing for discontinuation of CP 24 hours a day would have decreased the time to CP removal and potentially hours-to-bed arrival and idle bed hours, at our institution the ability to remove CP is restricted to those trained in Infection Prevention or their designees, and 24/7 coverage was not available.
Our capture of reduction in idle bed-hours was conservative. The analysis was limited to ED-based admissions within 30 days and did not account for any impact after this time period, and focused on the idle beds attributable to subjects in the study. This approach did not account for the potential impact on other inpatients that would be expected given the effect of the program on the relative proportions of CP and non-CP patients.
We did not assess the impact of the program on non-inpatient visits, resulting in a conservative estimate of the averted costs of CP. The potential effect of the screening program on MRSA transmission was not assessed. In the absence of the program, however, a large proportion of cleared subjects would have been falsely-cohorted with other positive patients, potentially exposing them to an increased risk of transmission.21
There are limitations to our findings. Despite rapid point-of-care alerting of ED staff to patient eligibility, more than two-thirds of all eligible visits were not assessed or assessed incorrectly by ED staff, and the majority of those visits were observed to be “misses” without any documentation of antibiotic assessment, no screening swab obtained, or both. A portion of excluded subjects included those in whom swabs were obtained but the swab result could not be acted upon because of lack of accurate documentation of antibiotic exposure. The costs of those tests were incorporated into the costs of the program. Approximately nine months into the program, due to continued poor capture within the ED, a Clinical Research Coordinator (CRC) was hired in order to improve program performance. In the period following, performance improved dramatically, with more than 80% of ED visits resulting in appropriate assessment and screening. The challenges of implementing such a program in a busy ED setting cannot be underestimated. With close to 300 visits a day to our Emergency Department, incorporation of a simple process of antibiotic documentation and patient swabbing was not successful until a dedicated individual was hired for this purpose.
PCR has been demonstrated to have high sensitivity and specificity compared to culture methods, however, both false-positive results (which would lead to patients remaining on CP unnecessarily) and false-negative results (which would lead to discontinuation of CP in the setting of persistent colonization) will still occur. Despite this, given the demonstrated high negative predictive value (NPV) compared to culture assays,10,22–24 we believe the targeted screening of patients who would otherwise continue on MRSA CP is an appropriate and valid use of the assay. In fact, the lower sensitivity of culture assays provides the rationale supporting protocols that require multiple sequential cultures to confirm clearance, with the attendant logistical challenges generated. We sampled the bilateral nares of subjects, however, extranasal colonization in the absence of nasal colonization has been observed.21 Sampling of nares alone, however, has been shown to provide similar NPV when sampling the nares compared to multiple body sites.21,24,25
The study did not randomize subjects to be screened, and there were observed differences between the MRSA-cleared and MRSA-colonized patients. We did not explicitly account for any clinical consequences or costs associated with patients who initially were documented MRSA-cleared and who subsequently were found to be either infected with MRSA or colonized on repeat sampling performed in the course of clinical care; based on routine infection control surveillance we believe this to be an uncommon occurrence. We did not assess the impact of the program from the perspective of the patient or healthcare worker, both vantage points that would likely provide additional support for efforts to identify which patients require CP for prevention of transmission. Initial capital investment costs for the PCR machine were not included. These costs are likely to vary across institutions. Finally, this program was implemented at a large, tertiary care, teaching hospital with a particular distribution of semi-private and private accommodations. While the exact ratio or semi-private:private rooms may differ compared to other hospitals, given that most hospitals include both types of accommodations, these findings are relevant beyond one specific institution.
Conclusion
In conclusion, as hospitals grapple with an ever-increasing demand for emergency evaluations, inpatient services and the possible need for surge capacity, efficient use of existing beds is paramount. We have shown that a targeted program for discontinuation of MRSA CP in patients who are no longer colonized is a practical and cost-saving approach.
Acknowledgments
The authors thank the subjects for participating in the program. Study data were collected and managed using the REDCap Electronic Data Capture tools hosted by Partners HealthCare Research Computing, Enterprise Research Infrastructure & Services group. The authors additionally acknowledge:
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MGH Infection Control Unit for their support and assistance in implementing the program: Delores (Dee Dee) Suslak, MSN, CIC, Paula Wright, RN, BSN, CIC, Irene Goldenshtein, MS, Fred Hawkins, RN, MHR, CIC, Kathleen Hoffman, RN, BS, CIC, Katherine Kakwi, RN, MSN, MBA, CIC, Janet A. Molina, Heidi Schleicher, RN, BSN, CIC, Nancy Swanson, RN, BSN, CIC, and Judith A. Tarselli, RN.
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MGH Microbiology Laboratory for assistance in specimen processing: Eric S. Rosenberg, MD, Mary Jane Ferraro, PhD, MPH, Heather Wilson and Joseph E. Braidt.
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Partners Information Systems for development and implementation of automated patient identification and clinician notification: Keith Jennings, MBA, and Douglas Kelbaugh.
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MGH Admitting Services for providing data on idle beds and helpful discussions on bed allocation: Ben Orcutt, MHA and Kathryn M. Cappallo.
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MGH pilot site staff for their dedication in implementing the MRSA Ambulatory Pilot Project: Benjamin A. White, MD, Paul Biddinger, MD, FACEP, Maryfran Hughes RN, MSN, John Tobias Nagurney, MD, MPH, Blair Alden Parry, CCRC, BA, Ryan T. Callahan BS, Emily R. Douglass, Ikenna G. Okechukwu MD, MBA, Eric Isaac Kagan Riklin, Rebecca Y. Lee, MPH, Joan Niles RN, Asmaa A. Sahrour, Amy Wheeler, MD, Erin Leigh Kane, RN, Alma Rivera, Sinead Bridget Dowd, Mary M. Gill, Roger Pasinski, MD, Jean Kwo, MD, and Doreen McPherson, RN.
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MGH Clinical Pathology Department for assistance in creating program-specific requisitions: George Souza, BS, MT, PBT, ASCP.
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MGH Materials Management for provision of cost of gowns, gloves and stethoscopes: Ed Raeke, Lisa Martino, James Burns.
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MGH Finance for providing data and insight into projected bed-level revenue: Cindy Aiena, MBA.
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MGH Medical Practice Evaluation Center for assistance in identification of private and semi-private room designations: Erin Ryan, MPH.
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MGH LMR Team for assistance in development of electronic documentation of screening results: Anselmo Ribeiro.
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Brigham and Women’s Hospital (BWH) Infection Control Department for assistance in reciprocal CP removal for patients cleared as part of the MAPP: Margaret V. Holmes, MSPH, CIC, Pamela Fox, RN, Candace Hsieh, RN, CIC, and Susan O’Rourke, RN, BSN, CIC.
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Lauren West, MPH, MGH Infection Control Unit, for assistance with manuscript preparation for submission.
Financial Support
This work was supported by KL2 RR025757-03 (National Center for Research Resources), UL1TR001102 (Harvard Catalyst | The Harvard Clinical and Translational Science Center; National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health; with financial contributions from Harvard University and its affiliated academic healthcare centers), K01AI110524 (National Institute of Allergy and Infectious Diseases, National Institutes of Health), Center for Integration of Medicine and Innovative Technology CIMIT under U.S. Army Medical Research Acquisition Activity Cooperative Agreement (CIMIT No. 12-1082), and Departmental Funds from the MGH Infection Control Unit. The funders did not contribute to the design or conduct of the study; in the collection, management, analysis or interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication. The content of the manuscript is solely the responsibility of the authors and does not necessarily represent the official views of any funders.
Footnotes
This research was presented in abstract form at ID Week 2014 (abstract #313) and as an oral presentation the International Symposium on Staphylococci and Staphylococcal Infections 2014.
REFERENCES
- 1.Dantes R, Mu Y, Belflower R, Aragon D, Dumyati G, Harrison LH, et al. National burden of invasive methicillin-resistant Staphylococcus aureus infections, United States, 2011. JAMA Intern Med. 2013;173:1970–1978. doi: 10.1001/jamainternmed.2013.10423. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Jarvis WR, Jarvis AA, Chinn RY. National prevalence of methicillin-resistant Staphylococcus aureus in inpatients at United States health care facilities, 2010. Am J Infect Control. 2012;40:194–200. doi: 10.1016/j.ajic.2012.02.001. [DOI] [PubMed] [Google Scholar]
- 3.Siegel JD, Rhinehart E, Jackson M, Chiarello L Health Care Infection Control Practices Advisory Committee. 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Health Care Settings. Am J Infect Control. 2007;35:S65–S164. doi: 10.1016/j.ajic.2007.10.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Scanvic A, Denic L, Gaillon S, Giry P, Andremont A, Lucet JC. Duration of colonization by methicillin-resistant Staphylococcus aureus after hospital discharge and risk factors for prolonged carriage. Clin Infect Dis. 2001;32:1393–1398. doi: 10.1086/320151. [DOI] [PubMed] [Google Scholar]
- 5.Robicsek A, Beaumont JL, Peterson LR. Duration of colonization with methicillin-resistant Staphylococcus aureus. Clin Infect Dis. 2009;48:910–913. doi: 10.1086/597296. [DOI] [PubMed] [Google Scholar]
- 6.Vriens MR, Blok HE, Gigengack-Baars AC, Mascini EM, van der Werken C, Verhoef J, et al. Methicillin-resistant Staphylococcus aureus carriage among patients after hospital discharge. Infect Control Hosp Epidemiol. 2005;26:629–633. doi: 10.1086/502592. [DOI] [PubMed] [Google Scholar]
- 7.Shenoy ES, Paras ML, Noubary F, Walensky RP, Hooper DC. Natural history of colonization with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE): a systematic review. BMC Infect Dis. 2014;14:177. doi: 10.1186/1471-2334-14-177. 2334-14-177. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Cluzet VC, Gerber JS, Nachamkin I, Metlay JP, Zaoutis TE, Davis MF, et al. Duration of Colonization and Determinants of Earlier Clearance of Colonization With Methicillin-Resistant Staphylococcus aureus. Clinical Infectious Diseases. 2015;60:1489–1496. doi: 10.1093/cid/civ075. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Siegel JD, Rhinehart E, Jackson M, Chiarello L. Healthcare Infection Control Practices Advisory Committee. Management of multidrug-resistant organisms in health care settings, 2006. Am J Infect Control. 2007;35:S165–S193. doi: 10.1016/j.ajic.2007.10.006. [DOI] [PubMed] [Google Scholar]
- 10.Shenoy ES, Kim J, Rosenberg ES, Cotter JA, Lee H, Walensky RP, et al. Discontinuation of contact precautions for methicillin-resistant staphylococcus aureus: a randomized controlled trial comparing passive and active screening with culture and polymerase chain reaction. Clin Infect Dis. 2013;57:176–184. doi: 10.1093/cid/cit206. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Morgan DJ, Pineles L, Shardell M, Graham MM, Mohammadi S, Forrest GN, et al. The effect of contact precautions on healthcare worker activity in acute care hospitals. Infect Control Hosp Epidemiol. 2013;34:69–73. doi: 10.1086/668775. [DOI] [PubMed] [Google Scholar]
- 12.Health Forum. American Hospital Association (AHA) Annual Survey of Hospitals. Hospital Statistics, 2010. 2010 [Google Scholar]
- 13.AAMC and COTH. Quarterly Survey of Hospital Operations and Financial Performance. 2013 [Google Scholar]
- 14.McLemore A, Bearman G, Edmond MB. Effect of contact precautions on wait time from emergency room disposition to inpatient admission. Infect Control Hosp Epidemiol. 2011;32:298–299. doi: 10.1086/658913. [DOI] [PubMed] [Google Scholar]
- 15.Stelfox HT, Bates DW, Redelmeier DA. Safety of patients isolated for infection control. JAMA. 2003;290:1899–1905. doi: 10.1001/jama.290.14.1899. [DOI] [PubMed] [Google Scholar]
- 16.Harris AD, Pineles L, Belton B, Johnson JK, Shardell M, Loeb M, et al. Universal glove and gown use and acquisition of antibiotic-resistant bacteria in the ICU: a randomized trial. JAMA. 2013;310:1571–1580. doi: 10.1001/jama.2013.277815. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Blot S, Depuydt P, Vogelaers D, Decruyenaere J, De Waele J, Hoste E, et al. Colonization status and appropriate antibiotic therapy for nosocomial bacteremia caused by antibiotic-resistant gram-negative bacteria in an intensive care unit. Infect Control Hosp Epidemiol. 2005;26:575–579. doi: 10.1086/502575. [DOI] [PubMed] [Google Scholar]
- 18.Day HR, Perencevich EN, Harris AD, Gruber-Baldini AL, Himelhoch SS, Brown CH, et al. Depression, anxiety, and moods of hospitalized patients under contact precautions. Infect Control Hosp Epidemiol. 2013;34:251–258. doi: 10.1086/669526. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Day HR, Perencevich EN, Harris AD, Himelhoch SS, Brown CH, Gruber-Baldini AL, et al. Do contact precautions cause depression? A two-year study at a tertiary care medical centre. J Hosp Infect. 2011;79:103–107. doi: 10.1016/j.jhin.2011.03.026. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Abad C, Fearday A, Safdar N. Adverse effects of isolation in hospitalised patients: a systematic review. J Hosp Infect. 2010;76:97–102. doi: 10.1016/j.jhin.2010.04.027. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Baker SE, Brecher SM, Robillard E, Strymish J, Lawler E, Gupta K. Extranasal methicillin-resistant Staphylococcus aureus colonization at admission to an acute care Veterans Affairs hospital. Infect Control Hosp Epidemiol. 2010;31:42–46. doi: 10.1086/649222. [DOI] [PubMed] [Google Scholar]
- 22.Laurent C, Bogaerts P, Schoevaerdts D, Denis O, Deplano A, Swine C, et al. Evaluation of the Xpert MRSA assay for rapid detection of methicillin-resistant Staphylococcus aureus from nares swabs of geriatric hospitalized patients and failure to detect a specific SCCmec type IV variant. Eur J Clin Microbiol Infect Dis. 2010;29:995–1002. doi: 10.1007/s10096-010-0958-3. [DOI] [PubMed] [Google Scholar]
- 23.Roisin S, Laurent C, Nonhoff C, Deplano A, Hallin M, Byl B, et al. Positive predictive value of the Xpert MRSA assay diagnostic for universal patient screening at hospital admission: influence of the local ecology. Eur J Clin Microbiol Infect Dis. 2012;31:873–880. doi: 10.1007/s10096-011-1387-7. [DOI] [PubMed] [Google Scholar]
- 24.Hombach M, Pfyffer GE, Roos M, Lucke K. Detection of methicillin-resistant Staphylococcus aureus (MRSA) in specimens from various body sites: performance characteristics of the BD GeneOhm MRSA assay, the Xpert MRSA assay, and broth-enriched culture in an area with a low prevalence of MRSA infections. J Clin Microbiol. 2010;48:3882–3887. doi: 10.1128/JCM.00670-10. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Wassenberg MW, Kluytmans JA, Bosboom RW, Buiting AG, van Elzakker EP, Melchers WJ, et al. Rapid diagnostic testing of methicillin-resistant Staphylococcus aureus carriage at different anatomical sites: costs and benefits of less extensive screening regimens. Clin Microbiol Infect. 2011;17:1704–1710. doi: 10.1111/j.1469-0691.2011.03502.x. [DOI] [PubMed] [Google Scholar]