Epidemiology, Timing, and Secondary Prophylaxis of Recurrent Nocardiosis

Background

Nocardia tends to cause infection in immunocompromised patients or those with chronic pulmonary disease. Nocardia is known to recur, prompting the practice of secondary prophylaxis in patients perceived at high risk. However, few data exist regarding the epidemiology of recurrent nocardiosis or the effectiveness of secondary prophylaxis.

Methods

We performed a multicenter, retrospective cohort study of adults diagnosed with nocardiosis from November 2011 to April 2022, including patients who completed primary treatment and had at least 30 days of posttreatment follow-up. Propensity score matching was used to analyze the effect of secondary prophylaxis on Nocardia recurrence.

Results

Fifteen of 303 (5.0%) patients developed recurrent nocardiosis after primary treatment. Most recurrences were diagnosed either within 60 days (N = 6/15, 40.0%) or between 2 to 3 years (N = 4/15, 26.7%). Patients with primary disseminated infection tended to recur within 1 year, whereas later recurrences were often nondisseminated pulmonary infection. Seventy-eight (25.7%) patients were prescribed secondary prophylaxis, mostly trimethoprim-sulfamethoxazole (N = 67/78). After propensity-matching, secondary prophylaxis was not associated with reduced risk of recurrence (hazard ratio, 0.96; 95% confidence interval, .24-3.83), including in multiple subgroups. Eight (53.3%) patients with recurrent nocardiosis required hospitalization and no patients died from recurrent infection.

Conclusions

Recurrent nocardiosis tends to occur either within months because of the same Nocardia species or after several years with a new species. Although we did not find evidence for the effectiveness of secondary prophylaxis, the confidence intervals were wide. However, outcomes of recurrent nocardiosis are generally favorable and may not justify long-term antibiotic prophylaxis for this indication alone.

Outcomes of transplant recipients with pretransplant Nocardia colonization or infection

BACKGROUND

Specific pretransplant infections have been associated with poor posttransplant outcomes. However, the impact of pretransplant Nocardia isolation has not been studied.

METHODS

We performed a retrospective study from three centers in Arizona, Florida, and Minnesota of patients with Nocardia infection or colonization who subsequently underwent solid organ or hematopoietic stem cell transplantation from November 2011 through April 2022. Outcomes included posttransplant Nocardia infection and mortality.

RESULTS

Nine patients with pretransplant Nocardia were included. Two patients were deemed colonized with Nocardia, and the remaining seven had nocardiosis. These patients underwent bilateral lung (N = 5), heart (N = 1), heart-kidney (N = 1), liver-kidney (N = 1), and allogeneic stem cell transplantation (N = 1) at a median of 283 (interquartile range [IQR] 152-283) days after Nocardia isolation. Two (22.2%) patients had disseminated infection, and two were receiving active Nocardia treatment at the time of transplantation. One Nocardia isolate was resistant to trimethoprim-sulfamethoxazole (TMP-SMX) and all patients received TMP-SMX prophylaxis posttransplant, often for extended durations. No patients developed posttransplant nocardiosis during a median follow-up of 1.96 (IQR 0.90-6.33) years. Two patients died during follow-up, both without evidence of nocardiosis.

CONCLUSIONS

This study did not identify any episodes of posttransplant nocardiosis among nine patients with pretransplant Nocardia isolation. As patients with the most severe infections may have been denied transplantation, further studies with larger sample sizes are needed to better analyze any impact of pretransplant Nocardia on posttransplant outcomes. However, among patients who receive posttransplant TMP-SMX prophylaxis, these data suggest pretransplant Nocardia isolation may not impart a heightened risk of posttransplant nocardiosis.

Risk factors and prophylaxis for nocardiosis in solid organ transplant recipients: A nested case-control study

BACKGROUND

Nocardia is an opportunistic pathogen that primarily affects immunocompromised individuals, including solid organ transplant (SOT) recipients. Up to 2.65% of SOT recipients develop nocardiosis; however, few studies have examined risk factors and prophylaxis for nocardiosis.

METHODS

We performed a multicenter, matched nested case-control study of adult SOT recipients with culture-confirmed nocardiosis from 2000 through 2020. Controls were matched up to 2:1 by sex, first transplanted organ, year of transplant, transplant center, and adequate post-transplant follow-up. Multivariable conditional logistic regression was performed to analyze associations with nocardiosis. Cox proportional hazards regression compared 12-month mortality between infection and uninfected patients.

RESULTS

One hundred and twenty-three SOT recipients were matched to 245 uninfected controls. Elevated calcineurin inhibitor level, acute rejection, cytomegalovirus infection, lymphopenia, higher prednisone dose, and older age were significantly associated with nocardiosis while trimethoprim-sulfamethoxazole prophylaxis was protective (odds ratio [OR] .34; 95% confidence interval [CI] .13-.84). The effect of prophylaxis was similar, though not always statistically significant, in sensitivity analyses that only included prophylaxis dosed more than twice-per-week (OR .30; 95% CI .11-.80) or restricted to years 2015-2020 (OR .33, 95% CI .09-1.21). Nocardiosis was associated with increased 12-month mortality (hazard ratio 5.47; 95% confidence interval 2.42-12.35).

CONCLUSIONS

Multiple measures of immunosuppression and lack of trimethoprim-sulfamethoxazole prophylaxis were associated with nocardiosis in SOT recipients. Effectiveness of prophylaxis may be related to trimethoprim-sulfamethoxazole dose or frequency. Trimethoprim-sulfamethoxazole should be preferentially utilized over alternative agents in SOT recipients with augmented immunosuppression or signs of heightened immunocompromise.

Mortality After Nocardiosis: Risk Factors and Evaluation of Disseminated Infection

Background

Nocardia primarily infects patients who are immunocompromised or those with chronic lung disease. Although disseminated infection is widely recognized as an important prognostic factor, studies have been mixed on its impact on outcomes of nocardiosis.

Methods

We performed a retrospective cohort study of adults with culture-confirmed nocardiosis. Advanced infection was defined as disseminated infection, cavitary pulmonary infection, or pleural infection. The primary outcome was 1-year mortality, as analyzed by multivariable Cox regression.

Results

Of 511 patients with culture growth of Nocardia, 374 (73.2%) who had clinical infection were included. The most common infection sites were pulmonary (82.6%), skin (17.9%), and central nervous system (14.2%). In total, 117 (31.3%) patients had advanced infection, including 74 (19.8%) with disseminated infection, 50 (13.4%) with cavitary infection, and 18 (4.8%) with pleural infection. Fifty-nine (15.8%) patients died within 1 year. In multivariable models, disseminated infection was not associated with mortality (hazard ratio, 1.16; 95% CI, .62-2.16; P = .650) while advanced infection was (hazard ratio, 2.48; 95% CI, 1.37-4.49; P = .003). N. farcinica, higher Charlson Comorbidity Index, and culture-confirmed pleural infection were also associated with mortality. Immunocompromised status and combination therapy were not associated with mortality.

Conclusions

Advanced infection, rather than dissemination alone, predicted worse 1-year mortality after nocardiosis. N. farcinica was associated with mortality, even after adjusting for extent of infection. While patients who were immunocompromised had high rates of disseminated and advanced infection, immunocompromised status did not predict mortality after adjustment. Future studies should account for high-risk characteristics and specific infection sites rather than dissemination alone.

Candidemia in Patients With Cardiovascular Implantable Electronic Devices: Uncertainty in Management Based on Current International Guidelines

Background

In contrast to bloodstream infection due to a variety of bacteria in patients with cardiovascular implantable electronic devices (CIED), there are limited data regarding candidemia and risk of CIED infection.

Methods

All patients with candidemia and a CIED at Mayo Clinic Rochester between 2012 and 2019 were reviewed. Cardiovascular implantable electronic device infection was defined by (1) clinical signs of pocket site infection or (2) echocardiographic evidence of lead vegetations.

Results

A total of 23 patients with candidemia had underlying CIED; 9 (39.1%) cases were community onset. None of the patients had pocket site infection. The duration between CIED placement and candidemia was prolonged (median 3.5 years; interquartile range, 2.0-6.5). Only 7 (30.4%) patients underwent transesophageal echocardiography and 2 of 7 (28.6%) had lead masses. Only the 2 patients with lead masses underwent CIED extraction, but device cultures were negative for Candida species. Two (33.3%) of 6 other patients who were managed as candidemia without device infection subsequently developed relapsing candidemia. Cardiovascular implantable electronic device removal was done in both patients and device cultures grew Candida species. Although 17.4% of patients were ultimately confirmed to have CIED infection, CIED infection status was undefined in 52.2%. Overall, 17 (73.9%) patients died within 90 days of diagnosis of candidemia.

Conclusions

Although current international guidelines recommend CIED removal in patients with candidemia, the optimal management strategy remains undefined. This is problematic because candidemia alone is associated with increased morbidity and mortality as seen in this cohort. Moreover, inappropriate device removal or retention can both result in increased patient morbidity and mortality.

Comparison of Oral and Intravenous Definitive Antibiotic Therapy for Beta-Hemolytic Streptococcus Species Bloodstream Infections from Soft Tissue Sources: a Propensity Score-Matched Analysis

Beta-hemolytic streptococci are common causes of bloodstream infection (BSI). There is emerging data regarding oral antibiotics for BSI but limited for beta-hemolytic streptococcal BSI. We conducted a retrospective study of adults with beta-hemolytic streptococcal BSI from a primary skin/soft tissue source from 2015 to 2020. Patients transitioned to oral antibiotics within 7 days of treatment initiation were compared to those who continued intravenous therapy, after propensity score matching. The primary outcome was 30-day treatment failure (composite of mortality, infection relapse, and hospital readmission). A prespecified 10% noninferiority margin was used for the primary outcome. We identified 66 matched pairs of patients treated with oral and intravenous antibiotics as definitive therapy. Based on an absolute difference in 30-day treatment failure of 13.6% (95% confidence interval 2.4 to 24.8%), the noninferiority of oral therapy was not confirmed (P = 0.741); on the contrary, the superiority of intravenous antibiotics is suggested by this difference. Acute kidney injury occurred in two patients who received intravenous treatment and zero who received oral therapy. No patients experienced deep vein thrombosis or other vascular complications related to treatment. In patients treated for beta-hemolytic streptococcal BSI, those who transitioned to oral antibiotics by day 7 showed higher rates of 30-day treatment failure than propensity-matched patients. This difference may have been driven by underdosing of oral therapy. Further investigation into optimal antibiotic choice, route, and dosing for definitive therapy of BSI is needed.

Body temperature and infection in critically ill patients on continuous kidney replacement therapy

PURPOSE

Continuous kidney replacement therapy (CKRT) is an increasingly common intervention for critically ill patients with kidney failure. Because CKRT affects body temperature, detecting infections in patients on CKRT is challenging. Understanding the relation between CKRT and body temperature may facilitate earlier detection of infection.

METHODS

We retrospectively reviewed adult patients (≥ 18 years) admitted to the intensive care unit at Mayo Clinic in Rochester, Minnesota, from December 1, 2006, through November 31, 2015, who required CKRT. We summarized central body temperatures for these patients according to the presence or absence of infection.

RESULTS

We identified 587 patients who underwent CKRT during the study period, of whom 365 had infections, and 222 did not have infections. We observed no statistically significant differences in minimum (P = .70), maximum (P = .22), or mean (P = .55) central body temperature for patients on CKRT with infection vs. those without infection. While not on CKRT (before CKRT initiation and after cessation), all three body temperature measurements were significantly higher in patients with infection than in those without infection (all P < .02).

CONCLUSION

Body temperature is insufficient to indicate an infection in critically ill patients on CKRT. Clinicians should remain watchful for other signs, symptoms, and indications of infection in patients on CKRT because of expected high infection rates.

Outcomes of Nocardiosis and Treatment of Disseminated Infection in Solid Organ Transplant Recipients

BACKGROUND

Nocardia is an environmental pathogen with a predilection for causing opportunistic infections in immunocompromised patients, including solid organ transplant (SOT) recipients. Although risk factors have been identified for developing nocardiosis in this population, little is known regarding clinical factors resulting in poor outcomes. We evaluated a cohort of SOT recipients with nocardiosis for associations with 12-month mortality.

METHODS

We performed a multicenter retrospective cohort study of adult SOT recipients diagnosed with culture-confirmed nocardiosis from 2000 to 2020. Patients were followed for 12 months after diagnosis, unless abbreviated by mortality. Multivariable Cox regression was performed to analyze associations with 12-month mortality. A subgroup analysis of patients with disseminated nocardiosis was performed to analyze treatment variables.

RESULTS

A total of 125 SOT recipients met inclusion criteria; 12-month mortality was 16.8%. Liver transplantation (hazard ratio [HR] 3.52; 95% confidence interval [CI] 1.27-9.76) and time from symptom onset to presentation (HR 0.92/d; 95% CI 0.86-0.99) were independently associated with 12-month mortality, whereas disseminated infection was not (HR 1.23; 95% CI 0.49-3.13). No treatment-specific factors were significantly associated with mortality in 33 patients with disseminated nocardiosis, although survivors had a higher rate of linezolid use.

CONCLUSIONS

This study identified 2 independent associations with 12-month mortality, representing demographics and infection severity. Disseminated infection was not independently associated with poor outcomes, and specific sites of infection may be more important than dissemination itself. No treatment-specific factors were associated with mortality, though this analysis was likely underpowered. Further study of treatment strategies based on specific Nocardia syndromes is warranted.

Curbing the Delta Surge: Clinical Outcomes After Treatment With Bamlanivimab-Etesevimab, Casirivimab-Imdevimab, or Sotrovimab for Mild to Moderate Coronavirus Disease 2019

OBJECTIVE

To describe and compare the clinical outcomes of bamlanivimab-etesevimab, casirivimab-imdevimab, and sotrovimab treatment of mild to moderate coronavirus disease 2019 (COVID-19) during the severe acute respiratory coronavirus 2 (SARS-CoV-2) B.1.617.2 Delta surge.

METHODS

This is a retrospective study of high-risk patients who received bamlanivimab-etesevimab, casirivimab-imdevimab, and sotrovimab for mild to moderate COVID-19 between August 1, 2021, and December 1, 2021. Rates of severe disease, hospitalization, intensive care unit admission, and death were assessed.

RESULTS

Among 10,775 high-risk patients who received bamlanivimab-etesevimab, casirivimab-imdevimab, or sotrovimab for mild to moderate COVID-19 during the Delta surge, 287 patients (2.7%) developed severe disease that led to hospitalization, oxygen supplementation, or death within 30 days after treatment. The rates of severe disease were low among patients treated with bamlanivimab-etesevimab (1.2%), casirivimab-imdevimab (2.9%), and sotrovimab (1.6%; P<.01). The higher rate of severe outcomes among patients treated with casirivimab-imdevimab may be related to a significantly lower COVID-19 vaccination rate in that cohort. Intensive care unit admission was comparable among patients treated bamlanivimab-etesevimab, casirivimab-imdevimab, or sotrovimab (1.0%, 1.0%, and 0.4%, respectively).

CONCLUSION

This real-world study of a large cohort of high-risk patients shows low rates of severe disease, hospitalization, intensive care unit admission, and mortality after treatment with bamlanivimab-etesevimab, casirivimab-imdevimab, and sotrovimab for mild to moderate COVID-19 during the SARS-CoV-2 Delta surge.

Rebound Phenomenon After Nirmatrelvir/Ritonavir Treatment of Coronavirus Disease 2019 (COVID-19) in High-Risk Persons

In a cohort of 483 high-risk patients treated with nirmatrelvir/ritonavir for COVID-19, 2 patients (0.4%) required hospitalization by day 30. Four patients (0.8%) experienced rebound of symptoms, which were generally mild, at a median of 9 days after treatment, and all resolved without additional COVID-19-directed therapy.

Rates of Severe Outcomes After Bamlanivimab-Etesevimab and Casirivimab-Imdevimab Treatment of High-Risk Patients With Mild to Moderate Coronavirus Disease 2019

Bamlanivimab-etesevimab and casirivimab-imdevimab are authorized by the US Food and Drug Administration for emergency treatment of mild to moderate coronavirus disease 2019 (COVID-19) in high-risk persons. There has been no study comparing their clinical efficacy. In this retrospective study of 681 patients with mild to moderate COVID-19 during a period dominated by severe acute respiratory syndrome coronavirus 2 wild-type and alpha variants, 25 patients (3.7%) had progression to a severe outcome requiring hospitalization and oxygen supplementation within 30 days after monoclonal antibody infusion. Severe outcome was significantly higher among the 181 patients who were treated with casirivimab-imdevimab when compared with the 500 patients who received bamlanivimab-etesevimab (21 [6.6%] vs 13 [2.6%]; P=.01). Patients treated with casirivimab-imdevimab had higher odds of severe outcomes compared with those who received bamlanivimab-etesevimab (odds ratio, 2.67; 95% CI, 1.17 to 6.06). The demographic and clinical characteristics, and the time to monoclonal antibody infusion, of the 2 treatment cohorts were not significantly different. The reason behind this significant difference in the clinical outcomes is unclear, but our observations emphasize potential efficacy differences among antispike monoclonal antibodies against COVID-19. Further clinical studies using larger cohorts of patients are needed to confirm or refute these observations.

Utility of Follow-up COVID-19 Antigen Tests After Acute SARS-CoV-2 Infection Among Healthcare Personnel

We report the utility of rapid antigen tests (RAgT) in a cohort of US healthcare personnel with coronavirus disease 2019 (COVID-19) infection who met symptom criteria to return to work at day 5 or later of isolation. In total, 11.9% of initial RAgT were negative. RAgT can be helpful to guide return to work decisions.

Effectiveness of Monoclonal Antibodies in Preventing Severe COVID-19 With Emergence of the Delta Variant

Anti-spike monoclonal antibodies have proven invaluable in preventing severe outcomes from COVID-19, including hospitalization and death. The rise of the SARS-CoV-2 delta variant begs the question of whether monoclonal antibodies maintain similar efficacy now as they had when the alpha and beta variants predominated, when they were first assessed and approved. We used a retrospective cohort to compare rates of severe outcomes in an epoch in which alpha and beta were predominant compared with delta. A total of 5356 patients were infused during the alpha/beta variant-predominant (n=4874) and delta variant-predominant (n=482) era. Overall, odds of severe infection were 3.0% of patients in the alpha/beta-predominant era compared with 4.9% in the delta-predominant cohort. The unadjusted odds ratio (OR) was higher for severe disease in the delta era (OR, 1.67; 95% CI, 0.96 to 2.89), particularly when adjusted for Charlson Comorbidity Index (adjusted OR, 2.04; 95% CI, 1.30 to 3.08). The higher odds of severe infection could be due to a more virulent delta variant, although the possibility of decreased anti-spike monoclonal antibody effectiveness in the clinical setting cannot be excluded. Research into the most effective strategies for using and improving anti-spike monoclonals for the treatment of emerging variants is warranted.

Contemporary Experience of Abiotrophia, Granulicatella and Gemella Bacteremia

BACKGROUND

Abiotrophia, Granulicatella, and Gemella are gastrointestinal microbiota, gram-positive cocci that behave like viridans group streptococci. Despite the low incidence of bacteremia from these organisms, they can lead to infective endocarditis (IE) and other clinical syndromes. Due to scant data, we aim to describe detailed clinical features, management, and outcomes of patients with bacteremia from these organisms.

METHODS

We reviewed all adult patients who developed Abiotrophia, Granulicatella, or Gemella bacteremia from 2011 to 2020, at Mayo Clinic.

RESULTS

We identified 238 patients with positive blood culture for these organisms. Of those, 161 (67.6%) patients were deemed to have bacteremia of clinical significance; 62 (38.5%) were neutropenic, - none of whom were diagnosed with IE. The primary source of bacteremia for the neutropenic group was the gastrointestinal tract. Among 161 patients, echocardiography was obtained in 88 (54.7%) patients, especially those with unknown sources of bacteremia. A total of 19 cases had IE: 5 (26.3%) Abiotrophia, 11 (57.9%) Granulicatella, and 3 (15.8%) Gemella. Based on known IE scoring systems, the negative predictive value at established cutoffs for these scores, performed with our cohort were 95.9%, 100% and 97.9% for NOVA, HANDOC and DENOVA scores, respectively. We also found that the penicillin-non-susceptible rate was high in Abiotrophia (66.7%) and Granulicatella (53.7%).

CONCLUSIONS

We described unique characteristics of Abiotrophia, Granulicatella, and Gemella bacteremia at our institution. Clinical significance, clinical syndrome, their proclivity of endocarditis, and susceptibility pattern should be thoroughly reviewed when encountering these organisms.

Diagnostic Value of 16S Ribosomal RNA Gene Polymerase Chain Reaction/Sanger Sequencing in Clinical Practice

BACKGROUND

Accurate microbiologic diagnosis is important for appropriate management of infectious diseases. Sequencing-based molecular diagnostics are increasingly used for precision diagnosis of infections. However, their clinical utility is unclear.

METHODS

We conducted a retrospective analysis of specimens that underwent 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR) followed by Sanger sequencing at our institution from April 2017 through March 2019.

RESULTS

A total of 566 specimens obtained from 460 patients were studied. Patients were considered clinically infected or noninfected based on final diagnosis and management. In 17% of patients, 16S rRNA PCR/sequencing was positive and in 5% of patients, this test led to an impact on clinical care. In comparison, bacterial cultures were positive in 21% of patients. Specimens with a positive Gram stain had 12 times greater odds of having a positive molecular result than those with a negative Gram stain (95% confidence interval for odds ratio, 5.2-31.4). Overall, PCR positivity was higher in cardiovascular specimens (37%) obtained from clinically infected patients, with bacterial cultures being more likely to be positive for musculoskeletal specimens (P < .001). 16S rRNA PCR/sequencing identified a probable pathogen in 10% culture-negative specimens.

CONCLUSION

16S rRNA PCR/sequencing can play a role in the diagnostic evaluation of patients with culture-negative infections, especially those with cardiovascular infections.

Outcomes of COVID-19 With the Mayo Clinic Model of Care and Research

OBJECTIVE

To report the Mayo Clinic experience with coronavirus disease 2019 (COVID-19) related to patient outcomes.

METHODS

We conducted a retrospective chart review of patients with COVID-19 diagnosed between March 1, 2020, and July 31, 2020, at any of the Mayo Clinic sites. We abstracted pertinent comorbid conditions such as age, sex, body mass index, Charlson Comorbidity Index variables, and treatments received. Factors associated with hospitalization and mortality were assessed in univariate and multivariate models.

RESULTS

A total of 7891 patients with confirmed COVID-19 infection with research authorization on file received care across the Mayo Clinic sites during the study period. Of these, 7217 patients were adults 18 years or older who were analyzed further. A total of 897 (11.4%) patients required hospitalization, and 354 (4.9%) received care in the intensive care unit (ICU). All hospitalized patients were reviewed by a COVID-19 Treatment Review Panel, and 77.5% (695 of 897) of inpatients received a COVID-19-directed therapy. Overall mortality was 1.2% (94 of 7891), with 7.1% (64 of 897) mortality in hospitalized patients and 11.3% (40 of 354) in patients requiring ICU care.

CONCLUSION

Mayo Clinic outcomes of patients with COVID-19 infection in the ICU, hospital, and community compare favorably with those reported nationally. This likely reflects the impact of interprofessional multidisciplinary team evaluation, effective leveraging of clinical trials and available treatments, deployment of remote monitoring tools, and maintenance of adequate operating capacity to not require surge adjustments. These best practices can help guide other health care systems with the continuing response to the COVID-19 pandemic.

Long-term SARS-CoV-2 RNA shedding and its temporal association to IgG seropositivity

Longitudinal characterization of SARS-CoV-2 PCR testing from COVID-19 patient's nasopharynx and its juxtaposition with blood-based IgG-seroconversion diagnostic assays is critical to understanding SARS-CoV-2 infection durations. Here, we retrospectively analyze 851 SARS-CoV-2-positive patients with at least two positive PCR tests and find that 99 of these patients remain SARS-CoV-2-positive after 4 weeks from their initial diagnosis date. For the 851-patient cohort, the mean lower bound of viral RNA shedding was 17.3 days (SD: 7.8), and the mean upper bound of viral RNA shedding from 668 patients transitioning to confirmed PCR-negative status was 22.7 days (SD: 11.8). Among 104 patients with an IgG test result, 90 patients were seropositive to date, with mean upper bound of time to seropositivity from initial diagnosis being 37.8 days (95% CI: 34.3-41.3). Our findings from juxtaposing IgG and PCR tests thus reveal that some SARS-CoV-2-positive patients are non-hospitalized and seropositive, yet actively shed viral RNA (14 of 90 patients). This study emphasizes the need for monitoring viral loads and neutralizing antibody titers in long-term non-hospitalized shedders as a means of characterizing the SARS-CoV-2 infection lifecycle.

Initial SARS-CoV-2 PCR crossing point does not predict hospitalization and duration of PCR positivity

This study aimed to determine if the crossing point of the initial positive SARS-CoV-2 PCR test correlated with patient demographics, subsequent hospitalization, or duration of positivity. Seventy-three patients with two or more positive PCR tests had a median time of 23 days to two consecutive negative results.

Low Utility of Repeat Real-Time PCR Testing for SARS-CoV-2 in Clinical Specimens

In a multicenter cohort of 22,315 patients tested for COVID-19, 1676 (7.5%) had repeat testing via real-time polymerase chain reaction following an initial negative test. Of those retested within 7 days of their first negative test, only 2.0% had a positive result. This suggests that repeat testing from the same source is unlikely to provide additional information.

Long-term SARS-CoV-2 RNA Shedding and its Temporal Association to IgG Seropositivity

Analysis of 851 COVID-19 patients with a SARS-CoV-2-positive PCR at follow-up shows 99 patients remained SARS-CoV-2-positive after four weeks from initial diagnosis. Surprisingly, a majority of these long-term viral RNA shedders were not hospitalized (61 of 99), with variable PCR Crossing point values over the month post diagnosis. For the 851-patient cohort, the mean lower bound of viral RNA shedding was 17.3 days (SD: 7.8), and the mean upper bound of viral RNA shedding from 668 patients transitioning to confirmed PCR-negative status was 22.7 days (SD: 11.8). Among 104 patients with an IgG test result, 90 patients were seropositive to date, with mean upper bound of time to seropositivity from initial diagnosis being 37.8 days (95%CI: 34.3-41.3). Juxtaposing IgG/PCR tests revealed that 14 of 90 patients are non-hospitalized and seropositive yet shed viral RNA. This study emphasizes the need for monitoring viral loads and neutralizing antibody titers in long-term shedders.

1340. The Effect of Continuous Renal Replacement Therapy on Body Temperature in Patients with and without Infection

Background

Sepsis frequently leads to acute kidney injury. In severe cases, patients may require continuous renal replacement therapy (CRRT) which involves placement of a dialysis catheter and an extracorporeal blood filtration circuit. CRRT is commonly considered to “mask” fever, though this phenomenon has not been investigated.

Methods

We queried an institutional database of all patients on CRRT from 2007 to 2015 for inpatient temperature data and antibiotic administration records. Receipts of piperacillin–tazobactam, a carbapenem, or a third or fourth-generation cephalosporin, indicating a serious infection, were considered intervention arm. We analyzed temperatures recorded in the intensive care unit before, during, and after CRRT. Patients were divided into groups that did not receive antibiotics as well as those who did. Temperature data were Winsorized to correct for outliers. We also performed descriptive statistics for each group.

Results

There were 237,988 temperature readings for 1,568 ICU patients on CRRT. 1,153 patients received broad-spectrum antibiotics in ICU. In patients who received antibiotics in ICU and were presumed to have an infection, the mean temperature was 37.2°C prior to initiation of CRRT, 36.8°C while on CRRT, and 37.2°C following discontinuation of CRRT. In the 415 patients who did not receive IV antibiotics, the mean temperature was 36.9°C prior to initiation of CRRT, 36.6°C while on CRRT, and 37.0°C following discontinuation of CRRT. During each of the periods before, during, and after CRRT, patients who received antibiotics had significantly higher temperatures than those who did not (P < 0.001). Patients receiving antibiotics were generally younger (mean 60 years vs. 64 years, P < 0.001), had longer ICU stays (mean 29 days vs. 12 days, P < 0.001) and spent more time being ventilated (mean 23 days vs. 7 days, P < 0.001). The mean SOFA score on day one was similar (mean 11.1 in the antibiotic group and 10.5 in the other group).

Conclusion

This investigation suggests that patients have slightly lower temperatures while on CRRT, by on average less than half a degree. A similar effect is seen in both patients with infections as well as those without. Further work will be needed to determine what constitutes a true febrile response in this population.

Disclosures

All authors: No reported disclosures.

1834. Incremental Diagnostic Value of 16S Ribosomal RNA Gene Polymerase Chain Reaction/Sanger Sequencing in Clinical Practice

Background

Polymerase chain reaction (PCR)/sequencing targeting the 16S ribosomal RNA (rRNA) gene to detect bacteria in normally sterile tissues and fluids has become increasingly popular in clinical medicine. This culture-independent technique can detect bacteria that are nonviable or difficult to cultivate using conventional methods. The clinical value of this type of testing is not well defined. We aimed to assess the diagnostic value of 16S rRNA PCR/Sanger sequencing as a clinical diagnostic assay at Mayo Clinic.

Methods

This is an interim analysis of the first 173 of 478 patients who had 16S rRNA PCR/Sanger sequencing done on sterile tissues or fluids at our institution from April, 2017 to November, 2018 as part of routine clinical practice. Medical records are being retrospectively reviewed, with results compared with those of culture.

Results

We reviewed 207 specimens from 173 patients (musculoskeletal 79%, cardiovascular 7%, central nervous system 4%, other 9%) that underwent 16S rRNA PCR/Sanger sequencing by clinical request (Table 1). In 90% of these specimens, the test was pre-planned rather than added-on. Nine specimens were excluded from analysis, as cultures were not performed. Overall concordance of culture with PCR/sequencing was 81% (160/197; P < 0.0001). Of 44 culture-positive specimens, PCR detected the same bacterium in 21 (48%) (Table 2). 45% (20/44) of those with positive cultures and 46% of those with positive PCR/sequencing results had received prior antimicrobial therapy (Table 3). PCR was negative in 139/144 specimens that were culture-negative (97%). PCR/sequencing was helpful in detecting a putative bacterial pathogen in 4 patients with negative cultures (Table 4).

Conclusion

Overall, 16S rRNA PCR/Sanger sequencing improved diagnostic yield compared with culture in a minority of cases. The described assay is limited by its inability to detect polymicrobial infections, a technical limitation that could possibly be addressed using massive parallel sequencing. Careful selection of cases and a save and add-on approach may be more cost-effective than upfront testing, although this was requested in a minority of cases.

Disclosures

Robin Patel, MD, ASM and IDSA: Other Financial or Material Support, Travel reimbursement, editor’s stipends; CD Diagnostics, Merck, Hutchison Biofilm Medical Solutions, Accelerate Diagnostics, ContraFect, TenNor Therapeutics Limited, Shionogi: Grant/Research Support; Curetis, Specific Technologies, NextGen Diagnostics, PathoQuest, Qvella: Consultant; NBME, Up-to-Date, the Infectious Diseases Board Review Course: Honorarium recipient, Other Financial or Material Support; Patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic, and a patent on an anti-biofilm substance issued: Other Financial or Material Support, Patents.

427. Putting the ‘Eye’ in Spirochetes

Background

Ocular syphilis is an infrequent presentation of Treponema pallidum infection. It is often seen in association with neurosyphilis but can occur in isolation as well. Here we describe a case series of 10 patients with ocular syphilis seen at our institution.

Methods

Patients with a diagnosis of ocular syphilis at the three sites of Mayo Clinic were identified from June 2006 to February 2019. Patient’s baseline characteristics, clinical presentation, diagnostic testing, and treatment were abstracted from Electronic Medical Records.

Results

We identified 10 patients (17 eyes) during the study period, half being diagnosed in the last 5 years. The median age was 51 years (IQR 21–66), and the majority were males (7/10). Characteristics of the patients are outlined in Table 1. Common presenting symptoms included vision loss (8/10), photophobia (4/10), and irritation (5/10). Seven of 10 patients had bilateral involvement. Of the 17 eyes, 59% had pan-uveitis and 82% had disc edema (Table 2). Rapid Plasma Reagin (RPR) was positive in 9 patients and median serum RPR was 1:128 (IQR 1:2-1:1024). One patient was diagnosed with a positive TP-PA, and characteristic ocular findings. One patients had positive 16S Ribosomal RNA Gene PCR/Sanger Sequencing on vitreous humor specimen for Treponema species. The majority of patients had isolated ocular symptoms at presentation; two patients also had an associated skin rash. All patients underwent a lumbar puncture (LP). Half had pleocytosis (TNC > 5) and elevated protein elevated (mean 63.6 mg/dL), although not significantly high. 3/10 patients had VDRL positive in the CSF. Protein levels were much higher in those with positive VDRL. Each patient was treated with intravenous (IV) penicillin for at least 2 weeks. Nine patients received ocular steroids as well. At last available follow-up, 8 had complete and 1 had partial resolution. One had worsened eye findings with eventual scarring.

Conclusion

Our findings are congruent with increasing incidence of ocular syphilis nationwide. Bilateral eye involvement and pan-uveitis were the most common ocular findings. Although only 3 patients had a positive VDRL in the CSF, pleocytosis and elevated protein were found in a large number of patients. Majority of the patients had clinical resolution with appropriate treatment.

Disclosures

All authors: No reported disclosures.

Laryngeal histoplasmosis in a kidney transplant recipient

Histoplasma capsulatum is an endemic fungus that most oftenly causes a self-limiting illness but can result in severe infections in immunocompromised patients including pulmonary or extra-pulmonary disease. Rarely it can also cause a chronic progressive infection of the larynx. Herein, we report a case of laryngeal histoplasmosis in a kidney transplant patient who presented with progressive symptoms of several weeks of hoarseness, dysphagia and odynophagia. Laryngoscopic examination revealed thick plaques in the oropharynx with surrounding hyper-erythema and histopathology showed numerous intracellular yeasts forms consistent with H capsulatum. Patient was initiated on treatment with itraconazole. Infection of the larynx due to H capsulatum is highly uncommon and therefore can result in an inappropriate or delayed diagnosis. A review of literature showed four previously reported cases of laryngeal histoplasmosis in patients with solid organ transplant. This is the first case series of laryngeal histoplasmosis in transplant recipients.

Incidence and Effects of Seasonality on Nonpurulent Lower Extremity Cellulitis After the Emergence of Community-Acquired Methicillin-Resistant Staphylococcus aureus

Nonpurulent lower extremity cellulitis (NLEC) is a common clinical diagnosis, with β-hemolytic streptococci and Staphylococcus aureus considered to be the most frequent causes. In 1999, the US Public Health Service alerted clinicians to the presence of community-acquired methicillin-resistant S aureus (CA-MRSA) infections in 4 children in the upper Midwest. Since then, it has become a well-recognized cause of skin and soft-tissue infections, in particular, skin abscess. A previous population-based study of NLEC in Olmsted County, Minnesota, reported an unadjusted incidence rate of 199 per 100,000 person-years in 1999, but it is unknown whether CA-MRSA subsequently has affected NLEC incidence. We, therefore, sought to determine the population-based incidence of NLEC since the emergence of CA-MRSA. Age- and sex-adjusted incidence (per 100,000 persons) of NLEC was 176.6 (95% CI, 151.5-201.7). Incidence differed significantly between sexes with age-adjusted sex-specific rates of 133.3 (95% CI, 104.1-162.5) and 225.8 (95% CI, 183.5-268.0) in females and males, respectively. Seasonal incidence differed, with rates of 224.6 (95% CI, 180.9-268.4) in warmer months (May-September) compared with 142.3 (95% CI, 112.8-171.9) in colder months (January-April and October-December). Despite emergence and nationwide spread of CA-MRSA since 1999 in the United States, the incidence of NLEC in Olmsted County was lower in 2013 than in 1999, particularly in females. This suggests that CA-MRSA is not a significant cause of NLEC and that NLEC cases are seasonally distributed. These findings may be important in formulation of empirical therapy for NLEC and in patient education because many patients with NLEC are prone to recurrent bouts of this infection.

Effect of the American Heart Association 2007 Guidelines on the Practice of Dental Prophylaxis for the Prevention of Infective Endocarditis in Olmsted County, Minnesota

OBJECTIVE

To determine the adherence of dental providers to the 2007 American Heart Association (AHA) infective endocarditis prevention guidelines regarding antibiotic drug administration before invasive dental procedures.

PATIENTS AND METHODS

The study included all adults (≥18 years old) with a moderate-risk (MR) or high-risk (HR) cardiac condition who received dental care at participating dental offices from January 1, 2005, through June 1, 2015, in Olmsted County, Minnesota. Data collected included the date and type of dental procedure performed and receipt of antibiotic prophylaxis (AP).

RESULTS

A total of 1351 patients underwent 8854 dental visits at participating dental offices during the study period; 1236 patients had an MR cardiac condition and 115 had an HR condition. The percentage of visits in which antibiotic drugs were used for indicated dental procedures in the MR group declined from 64.6% before to 8.6% after publication of the 2007 AHA guidelines (P<.001); for the HR group, AP declined from 96.9% before to 81.3% after publication of the guidelines (P=.02).

CONCLUSION

In this historical cohort in Olmsted County there was a statistically significant reduction in AP in the MR group before invasive dental procedures. In addition, there was an unanticipated significant reduction in AP in the HR group after publication of the 2007 AHA guidelines. These findings can be used to provide feedback and education to medical and dental professionals who are involved in decision making regarding the use of dental prophylaxis for their patients.