Presymptomatic SARS-CoV-2 Infections and Transmission in a Skilled Nursing Facility

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can spread rapidly within skilled nursing facilities. After identification of a case of Covid-19 in a skilled nursing facility, we assessed transmission and evaluated the adequacy of symptom-based screening to identify infections in residents.

METHODS

We conducted two serial point-prevalence surveys, 1 week apart, in which assenting residents of the facility underwent nasopharyngeal and oropharyngeal testing for SARS-CoV-2, including real-time reverse-transcriptase polymerase chain reaction (rRT-PCR), viral culture, and sequencing. Symptoms that had been present during the preceding 14 days were recorded. Asymptomatic residents who tested positive were reassessed 7 days later. Residents with SARS-CoV-2 infection were categorized as symptomatic with typical symptoms (fever, cough, or shortness of breath), symptomatic with only atypical symptoms, presymptomatic, or asymptomatic.

RESULTS

Twenty-three days after the first positive test result in a resident at this skilled nursing facility, 57 of 89 residents (64%) tested positive for SARS-CoV-2. Among 76 residents who participated in point-prevalence surveys, 48 (63%) tested positive. Of these 48 residents, 27 (56%) were asymptomatic at the time of testing; 24 subsequently developed symptoms (median time to onset, 4 days). Samples from these 24 presymptomatic residents had a median rRT-PCR cycle threshold value of 23.1, and viable virus was recovered from 17 residents. As of April 3, of the 57 residents with SARS-CoV-2 infection, 11 had been hospitalized (3 in the intensive care unit) and 15 had died (mortality, 26%). Of the 34 residents whose specimens were sequenced, 27 (79%) had sequences that fit into two clusters with a difference of one nucleotide.

CONCLUSIONS

Rapid and widespread transmission of SARS-CoV-2 was demonstrated in this skilled nursing facility. More than half of residents with positive test results were asymptomatic at the time of testing and most likely contributed to transmission. Infection-control strategies focused solely on symptomatic residents were not sufficient to prevent transmission after SARS-CoV-2 introduction into this facility.

Epidemiology of Covid-19 in a Long-Term Care Facility in King County, Washington

BACKGROUND

Long-term care facilities are high-risk settings for severe outcomes from outbreaks of Covid-19, owing to both the advanced age and frequent chronic underlying health conditions of the residents and the movement of health care personnel among facilities in a region.

METHODS

After identification on February 28, 2020, of a confirmed case of Covid-19 in a skilled nursing facility in King County, Washington, Public Health-Seattle and King County, aided by the Centers for Disease Control and Prevention, launched a case investigation, contact tracing, quarantine of exposed persons, isolation of confirmed and suspected cases, and on-site enhancement of infection prevention and control.

RESULTS

As of March 18, a total of 167 confirmed cases of Covid-19 affecting 101 residents, 50 health care personnel, and 16 visitors were found to be epidemiologically linked to the facility. Most cases among residents included respiratory illness consistent with Covid-19; however, in 7 residents no symptoms were documented. Hospitalization rates for facility residents, visitors, and staff were 54.5%, 50.0%, and 6.0%, respectively. The case fatality rate for residents was 33.7% (34 of 101). As of March 18, a total of 30 long-term care facilities with at least one confirmed case of Covid-19 had been identified in King County.

CONCLUSIONS

In the context of rapidly escalating Covid-19 outbreaks, proactive steps by long-term care facilities to identify and exclude potentially infected staff and visitors, actively monitor for potentially infected patients, and implement appropriate infection prevention and control measures are needed to prevent the introduction of Covid-19.

Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility - King County, Washington, March 2020

Older adults are susceptible to severe coronavirus disease 2019 (COVID-19) outcomes as a consequence of their age and, in some cases, underlying health conditions (1). A COVID-19 outbreak in a long-term care skilled nursing facility (SNF) in King County, Washington that was first identified on February 28, 2020, highlighted the potential for rapid spread among residents of these types of facilities (2). On March 1, a health care provider at a second long-term care skilled nursing facility (facility A) in King County, Washington, had a positive test result for SARS-CoV-2, the novel coronavirus that causes COVID-19, after working while symptomatic on February 26 and 28. By March 6, seven residents of this second facility were symptomatic and had positive test results for SARS-CoV-2. On March 13, CDC performed symptom assessments and SARS-CoV-2 testing for 76 (93%) of the 82 facility A residents to evaluate the utility of symptom screening for identification of COVID-19 in SNF residents. Residents were categorized as asymptomatic or symptomatic at the time of testing, based on the absence or presence of fever, cough, shortness of breath, or other symptoms on the day of testing or during the preceding 14 days. Among 23 (30%) residents with positive test results, 10 (43%) had symptoms on the date of testing, and 13 (57%) were asymptomatic. Seven days after testing, 10 of these 13 previously asymptomatic residents had developed symptoms and were recategorized as presymptomatic at the time of testing. The reverse transcription-polymerase chain reaction (RT-PCR) testing cycle threshold (Ct) values indicated large quantities of viral RNA in asymptomatic, presymptomatic, and symptomatic residents, suggesting the potential for transmission regardless of symptoms. Symptom-based screening in SNFs could fail to identify approximately half of residents with COVID-19. Long-term care facilities should take proactive steps to prevent introduction of SARS-CoV-2 (3). Once a confirmed case is identified in an SNF, all residents should be placed on isolation precautions if possible (3), with considerations for extended use or reuse of personal protective equipment (PPE) as needed (4).

COVID-19 in a Long-Term Care Facility - King County, Washington, February 27-March 9, 2020

On February 28, 2020, a case of coronavirus disease (COVID-19) was identified in a woman resident of a long-term care skilled nursing facility (facility A) in King County, Washington.* Epidemiologic investigation of facility A identified 129 cases of COVID-19 associated with facility A, including 81 of the residents, 34 staff members, and 14 visitors; 23 persons died. Limitations in effective infection control and prevention and staff members working in multiple facilities contributed to intra- and interfacility spread. COVID-19 can spread rapidly in long-term residential care facilities, and persons with chronic underlying medical conditions are at greater risk for COVID-19-associated severe disease and death. Long-term care facilities should take proactive steps to protect the health of residents and preserve the health care workforce by identifying and excluding potentially infected staff members and visitors, ensuring early recognition of potentially infected patients, and implementing appropriate infection control measures.

Risk Factors for 30-Day Mortality in Patients with Methicillin-Resistant Staphylococcus aureus Bloodstream Infections

OBJECTIVES

Methicillin-resistant Staphylococcus aureus (MRSA) blood stream infections (BSI) are a major health care problem accounting for a large percentage of nosocomial infections. The aim of this study was to identify risk factors associated with 30-day mortality in patients with MRSA BSI.

METHODS

This was a retrospective study performed in Southeast Michigan. Over a 9- year period, a total of 1,168 patients were identified with MRSA BSI. Patient demographics and clinical data were retrieved and evaluated using electronic medical health records.

RESULTS

30-day mortality during the 9-year study period was 16%. Significant risk factors for 30-day mortality were age, cancer, heart disease, neurologic disease, nursing home residence and Charlson score >3 with Odds Ratio (OR) of 1.03 (CI 1.02-1.04), 2.29 (CI 1.40-3.75), 1.78 (CI 1.20-2.63), 1.65 (CI 1.08-2.25), 1.66 (CI 1.02 - 2.70) and 1.86 (CI 1.18 - 2.95) correspondingly. Diabetes mellitus, peripheral vascular disease (PVD), and readmission were protective factors for 30-day mortality with OR of 0.53 (CI 0.36-0.78), 0.46 (CI 0.26-0.84) and 0.13 (CI0.05 - 0.32) respectively.

CONCLUSIONS

Our study identified significant risk factors for 30-day mortality in patients with MRSA BSI. Interestingly, diabetes mellitus, PVD and readmission were protective effects on 30-day mortality. There was no statistically significant variability in 30-day mortality over the 9-year study period.

Development and Validation of an Enzyme Immunoassay for Detection and Quantification of SARS-CoV-2 Salivary IgA and IgG

Oral fluids offer a noninvasive sampling method for the detection of Abs. Quantification of IgA and IgG Abs in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG Abs against the prefusion-stabilized form of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein expressed in suspension-adapted HEK-293 cells. Normalization against total Ab isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 prepandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA, 95.5%; IgG, 89.7%) without compromising specificity (IgA, 99%; IgG, 97%). No cross-reactivity with endemic coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/ml and 0.30 ng/ml, respectively. Salivary IgA and IgG Abs were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary Ab titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 wk in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.

Signs, Symptoms, and Comorbidities Associated With Onset and Prognosis of COVID-19 in a Nursing Home

Background

Effective halting of outbreaks in skilled nursing facilities (SNFs) depends on the earliest recognition of cases. We assessed confirmed COVID-19 cases at an SNF impacted by COVID-19 in the United States to identify early indications of COVID-19 infection.

Methods

We performed retrospective reviews of electronic health records for residents with laboratory-confirmed SARS-CoV-2 during February 28–March 16, 2020. Records were abstracted for comorbidities, signs and symptoms, and illness outcomes during the 2 weeks before and after the date of positive specimen collection. Relative risks (RRs) of hospitalization and death were calculated.

Results

Of the 118 residents tested among approximately 130 residents from Facility A during February 28–March 16, 2020, 101 (86%) were found to test positive for SARS-CoV-2. At initial presentation, about two-thirds of SARS-CoV-2–positive residents had an abnormal vital sign or change in oxygen status. Most (90.2%) symptomatic residents had elevated temperature, change in mental status, lethargy, change in oxygen status, or cough; 9 (11.0%) did not have fever, cough, or shortness of breath during their clinical course. Those with change in oxygen status had an increased relative risk (RR) of 30-day mortality [51.1% vs 29.7%, RR 1.7, 95% confidence interval (CI) 1.0–3.0]. RR of hospitalization was higher for residents with underlying hepatic disease (1.6, 95% CI 1.1–2.2) or obesity (1.5, 95% CI 1.1–2.1); RR of death was not statistically significant.

Conclusions and Implications

Our findings reinforce the critical role that monitoring of signs and symptoms can have in identifying COVID-19 cases early. SNFs should ensure they have a systematic approach for responding to abnormal vital signs and oxygen saturation and consider ensuring common signs and symptoms identified in Facility A are among those they monitor.

Multidrug-Resistant Microorganisms Colonizing Lower Extremity Wounds in Patients in a Tertiary Care Hospital, Lima, Peru

Multidrug-resistant organism (MDRO) infections cause high morbidity and mortality, and high costs to patients and hospitals. The study aims were to determine the frequency of MDRO colonization and associated factors in patients with lower-extremity wounds with colonization. A cross-sectional study was designed during November 2015 to July 2016 in a tertiary care hospital in Lima, Peru. A wound swab was obtained for culture and susceptibility testing. MDRO colonization was defined if the culture grew with methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, and/or extended spectrum beta-lactamase (ESBL) microorganisms. The frequency of MDRO wound colonization was 26.8% among the 97 patients enrolled. The most frequent MDRO obtained was ESBL-producing Escherichia coli, which was significantly more frequent in chronic wounds versus acute wounds (17.2% versus 0%, P < 0.05). Infection control measures should be implemented when patients with chronic lower-extremity wounds are admitted.

Development and validation of an enzyme immunoassay for detection and quantification of SARS-CoV-2 salivary IgA and IgG

Oral fluids offer a non-invasive sampling method for the detection of antibodies. Quantification of IgA and IgG antibodies in saliva allows studies of the mucosal and systemic immune response after natural infection or vaccination. We developed and validated an enzyme immunoassay (EIA) to detect and quantify salivary IgA and IgG antibodies against the prefusion-stabilized form of the SARS-CoV-2 spike protein. Normalization against total antibody isotype was performed to account for specimen differences, such as collection time and sample volume. Saliva samples collected from 187 SARS-CoV-2 confirmed cases enrolled in 2 cohorts and 373 pre-pandemic saliva samples were tested. The sensitivity of both EIAs was high (IgA: 95.5%; IgG: 89.7%) without compromising specificity (IgA: 99%; IgG: 97%). No cross reactivity with seasonal coronaviruses was observed. The limit of detection for SARS-CoV-2 salivary IgA and IgG assays were 1.98 ng/mL and 0.30 ng/mL, respectively. Salivary IgA and IgG antibodies were detected earlier in patients with mild COVID-19 symptoms than in severe cases. However, severe cases showed higher salivary antibody titers than those with a mild infection. Salivary IgA titers quickly decreased after 6 weeks in mild cases but remained detectable until at least week 10 in severe cases. Salivary IgG titers remained high for all patients, regardless of disease severity. In conclusion, EIAs for both IgA and IgG had high specificity and sensitivity for the confirmation of current or recent SARS-CoV-2 infections and evaluation of the IgA and IgG immune response.

Donor-derived transmission through lung transplantation of carbapenem-resistant Acinetobacter baumannii producing the OXA-23 carbapenemase during an ongoing healthcare facility outbreak

We describe a rare instance of donor-derived OXA-23-producing carbapenem-resistant Acinetobacter baumannii transmission during lung transplantation and the subsequent public health response. This investigation highlights how transplantation can introduce rare multidrug-resistant organisms into different healthcare facilities and regions.

Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility - King County, Washington, March 2020

Older adults are susceptible to severe coronavirus disease 2019 (COVID-19) outcomes as a consequence of their age and, in some cases, underlying health conditions (1). A COVID-19 outbreak in a long-term care skilled nursing facility (SNF) in King County, Washington that was first identified on February 28, 2020, highlighted the potential for rapid spread among residents of these types of facilities (2). On March 1, a health care provider at a second long-term care skilled nursing facility (facility A) in King County, Washington, had a positive test result for SARS-CoV-2, the novel coronavirus that causes COVID-19, after working while symptomatic on February 26 and 28. By March 6, seven residents of this second facility were symptomatic and had positive test results for SARS-CoV-2. On March 13, CDC performed symptom assessments and SARS-CoV-2 testing for 76 (93%) of the 82 facility A residents to evaluate the utility of symptom screening for identification of COVID-19 in SNF residents. Residents were categorized as asymptomatic or symptomatic at the time of testing, based on the absence or presence of fever, cough, shortness of breath, or other symptoms on the day of testing or during the preceding 14 days. Among 23 (30%) residents with positive test results, 10 (43%) had symptoms on the date of testing, and 13 (57%) were asymptomatic. Seven days after testing, 10 of these 13 previously asymptomatic residents had developed symptoms and were recategorized as presymptomatic at the time of testing. The reverse transcription-polymerase chain reaction (RT-PCR) testing cycle threshold (Ct) values indicated large quantities of viral RNA in asymptomatic, presymptomatic, and symptomatic residents, suggesting the potential for transmission regardless of symptoms. Symptom-based screening in SNFs could fail to identify approximately half of residents with COVID-19. Long-term care facilities should take proactive steps to prevent introduction of SARS-CoV-2 (3). Once a confirmed case is identified in an SNF, all residents should be placed on isolation precautions if possible (3), with considerations for extended use or reuse of personal protective equipment (PPE) as needed (4).

1208. Impact of Admission to an Inpatient Infectious Disease Unit on Methicillin-Resistant Staphylococcus aureus Bloodstream Infections

Background

Methicillin-resistant Staphylococcus aureus (MRSA) blood stream infection (BSI) remains a condition with high mortality. Despite the introduction of new antibiotics, the mortality in the past 10 years at our institution remains unchanged. To evaluate measures that improve outcomes in these patients (patients), we studied the impact of admission to an inpatient infectious disease (ID) unit.

Methods

We identified a retrospective cohort of patients with MRSA BSI at an 800-bed hospital in urban Detroit from January 2013 to February 2017. Patients were assigned to one of the three groups: group 1 was admission to inpatient ID unit where the ID doctors were the attending physicians, group 2 was ID consultation (without admission to ID unit), and group 3 was no ID consultation. Demographics, clinical information, and 30 day mortality from index blood culture were collected. Source of BSI was classified into four categories: primary (endovascular infection); secondary (respiratory, skin, osteomyelitis, abdominal and genitourinary infections); central line associated; unknown. Unpaired t-test and Fisher’s exact test were used to compare groups.

Results

A total of 477 patients were identified with MRSA BSI during the study period. 89 (18.7%) were in group 1, 299 (62%) in group 2 and 89 (18.7%) in group 3. Pt clinical characteristics and outcomes are shown in Table 1. Overall 30-day mortality was 21.4%. Comparison of mortality between groups are shown in Table 2.

Conclusion

While it is well established that ID consultation has improved outcomes in MRSA BSI, this is the first study that shows that admission to an inpatient ID unit decreases mortality even further.

Disclosures

All authors: No reported disclosures.

2098. Reduction of Central-Line-associated Bloodstream Infection Rates: Impact of Minimizing Blood Cultures from Central Lines

Background

CLABSI surveillance at our institution indicated that a significant proportion of CLABSI had a positive blood culture drawn from central line (CL-BC) with corresponding negative BC done by venipuncture (VP-BC), suggesting possible CL contamination. The contribution of minimizing CL-BC on CLABSI rates remains unknown. This study evaluates the impact on CLABSI rates of reducing CL-BC in addition to standard CLABSI reduction strategies in adult intensive care units (ICUs).

Methods

The study was done from January 1, 2015 to August 31, 2017 in adult ICUs at a hospital with 164 ICU beds, in urban Detroit. Education initiatives to minimize CL-BC were implemented in the ICU. Internal metrics VP-BC ratio (No. VP-BC/total BC in patients with CL) and CL-BC ratio (No. CL-BC/total BC in patients with CL) were used to monitor effectiveness. Compliance audits of CL maintenance were done, i.e., CL dressing intact, proper use of chlorhexidine dressing, site without redness or drainage. Monthly unit-specific CLABSI rates, CL utilization ratios (CL-UR), and VP-BC and CL-BC ratios were provided as feedback to the ICUs. CLABSI rates and number of contaminated BC were monitored. Trends of the various metrics were analyzed using Kendall Tau’s correlation for continuous variables. The relationship between CLABSI rate, VP-BC ratios and CL-UR were examined using Spearman’s correlation coefficient. Statistical significance was set at P < 0.05.

Results

During the study period in the ICU there were 148,762 patient-days and 82,153 CL days. Trends over time of the metrics are shown (figure). There was significant improvement noted in CLABSI rates, CL-UR and VP-BC rates (Table 1). There was a significant correlation between the CLABSI rates with VP-BC −0.395 (P value = 0.025) and a not significant correlation with CL-UR 0.278 (P value = 0.123). The number of contaminated blood cultures were 29, 3, and 0 in 2015, 2016 and 2017, respectively.

Conclusion

Minimizing BC obtained from CL can significantly contribute to reduction in CLABSI rates when used in combination with standard best care practices for CL insertion and maintenance.

Disclosures

All authors: No reported disclosures.

513. Transmission of Carbapenem-Resistant Enterobacteriaceae in a Community-Based, Residential Care Setting: Nevada, 2018

Background

Klebsiella pneumoniae carbapenemase-producing organisms (KPCOs) are often multidrug-resistant, and the KPC resistance determinant can be transmitted between bacteria. KPCOs are associated with healthcare facility exposures; identification in community-based, residential care settings is uncommon. In September 2018, the Washoe County Health District was notified of a KPC-producing Escherichia coli from a group home (GH) resident. We investigated the source of this KPCO and evaluated transmission in the GH.

Methods

A case was defined as detection of KPCO from a GH resident or staff from June 1 to November 30, 2018. Staff included caregivers who provided daily care (including toileting, bathing, feeding) and visiting healthcare workers. Residents and staff were offered KPCO screening to assess colonization status. Exposures were assessed by medical record review and interviews. Genetic relatedness of KPCOs was evaluated by whole-genome sequencing (WGS). Infection prevention and control (IPC) practices were reviewed.

Results

Overall, six cases were identified, including the index, two of seven staff screened and three of six residents screened. Three residents with KPCOs had recent hospitalizations and shared a bathroom in the GH; one overlapped on the same hospital unit as a patient with KPC-producing Klebsiella oxytoca. Staff with KPCOs were caregivers who had extensive contact with residents and their environment and no IPC training. Gaps in hand hygiene and environmental cleaning were observed. Organism was recovered from 4 positive screening tests as well as from blood cultures from the index case; all were KPC-producing E. coli. WGS showed that the five E. coli isolates were closely related, consistent with transmission, and harbored the same KPC variant as the K. oxytoca. No new cases occurred after IPC was improved.

Conclusion

A GH resident likely acquired KPCOs during a recent hospitalization, and extensive transmission among GH residents and staff occurred. Factors contributing to transmission included resident dependence on caregivers for daily care and minimal IPC knowledge among caregivers. Facilities with similar populations should increase IPC training to prevent transmission of resistant pathogens.

Disclosures

All authors: No reported disclosures.

Absence of SARS-CoV-2 infections among patients with end-stage renal disease following facility-wide testing in four outpatient hemodialysis facilities

Facility-wide testing performed at 4 outpatient hemodialysis facilities in the absence of an outbreak or escalating community incidence did not identify new SARS-CoV-2 infections and illustrated key logistical considerations essential to successful implementation of SARS-CoV-2 screening. Facilities could consider prioritizing facility-wide SARS-CoV-2 testing during suspicion of an outbreak in the facility or escalating community spread without robust infection control strategies in place. Being prepared to address operational considerations will enhance implementation of facility-wide testing in the outpatient dialysis setting.

Changes in Nasal Staphylococcus Colonization and Infection Rates After Nasal Surgery

Background: The relationship between nasal flora and infection rates in patients undergoing nasal surgery is of interest. This relationship has been studied though changes that may take place due to surgery have never been elucidated. Objective: To assess colonization rates and changes in colonization patterns of methicillin-resistant or methicillin-sensitive Staphylococcus aureus (MRSA/MSSA) in nasal flora in patients undergoing nasal surgery and to determine whether colonization is a risk factor for postoperative infection. Methods: Patients undergoing nasal surgery including septoplasty, rhinoplasty, or nasal valve repair were recruited prospectively. Patients completed a survey preoperatively concerning risk factors of postoperative infection. Nasal swabs and cultures were done preoperatively and at 1 week postoperatively. Patients were assessed for surgical site infections postoperatively. Results: Fifty-five patients completed both preoperative and postoperative nasal swabs. Preoperative to postoperative colonization rates increased for MRSA (2-5%) and MSSA (22-36%). Of the 55 patients, 11 had a change in nasal flora postoperatively, 9 of whom were colonized with a Staphylococcus aureus strain. However, MSSA/MRSA colonization either preoperatively or postoperatively was not associated with surgical site infections. Gender was the only variable found to be associated with postoperative infection (p = 0.007) with all four infections occurring in females. Conclusions: MSSA and MRSA do not appear to be major risk factors for surgical site infection in nasal surgery, whereas prior nasal surgery is a risk factor. This is the first report of a change in nasal colonization after nasal surgery. This could have implications for antibiotic prophylaxis in select nasal surgery cases.