Trends of antibiotic use at the end-of-life of cancer and non-cancer decedents: a nationwide population-based longitudinal study (2006-2018)

Objective

This study aimed to assess the actual burden of antibiotic use among end-of-life (EOL) patients in South Korea and to compare trends between cancer and non-cancer decedents.

Design

Population-based mortality follow-back study.

Setting

Data from the Korean National Health Insurance Database, covering the period from January1, 2006, to December 31, 2018, provided for research by the National Health Insurance Service (NHIS), were used.

Participants

All decedents from 2006 to 2018 were included and categorized as cancer decedents or non-cancer decedents.

Methods

Annual antibiotic consumption rates and prescription rates were calculated, and Poisson regression was used to estimate their trends.

Results

Overall antibiotic consumption rates decreased slightly among decedents in their final month with a less pronounced annual decrease rate among cancer decedents compared to non-cancer decedents (0.4% vs 2.3% per year, P <.001). Over the study period, although narrow spectrum antibiotics were used less, utilization and prescription of broad-spectrum antibiotics steadily increased, and prescription rates were higher in cancer decedents compared to non-cancer controls. Specifically, carbapenem prescription rates increased from 5.6% to 18.5%, (RR 1.087, 95% CI 1.085-1.088, P <.001) in cancer decedents and from 2.9% to 13.2% (RR 1.115, 95% CI 1.113-1.116, P <.001) in non-cancer decedents.

Conclusions

Our findings show that patients at the EOL, especially those with cancer, are increasingly and highly exposed to broad-spectrum antibiotics. Measures of antibiotic stewardship are required among this population.

Validation of a new risk stratification system-based management for methicillin-resistant Staphylococcus aureus bacteraemia: analysis of a multicentre prospective study

PURPOSE

Distinguishing between complicated and uncomplicated Staphylococcus aureus bacteraemia (SAB) is therapeutically essential. However, this distinction has limitations in reflecting the heterogeneity of SAB and encouraging targeted diagnostics. Recently, a new risk stratification system for SAB metastatic infection, involving stepwise approaches to diagnosis and treatment, has been suggested. We assessed its applicability in methicillin-resistant SAB (MRSAB) patients.

METHODS

We retrospectively analysed data of a 3-year multicentre, prospective cohort of hospitalised patients with MRSAB. We classified the patients into three risk groups: low, indeterminate, and high, based on the new system and compared between-group management and outcomes.

RESULTS

Of 380 patients with MRSAB, 6.3% were classified as low-, 7.6% as indeterminate-, and 86.1% as high-risk for metastatic infection. No metastatic infection occurred in the low-, 6.9% in the indeterminate-, and 19.6% in the high-risk groups (P < 0.001). After an in-depth diagnostic work-up, patients were finally diagnosed as 'without metastatic infection (6.3%)', 'with metastatic infection (17.4%)', and 'uncertain for metastatic infection (76.3%)'. 30-day mortality increased as the severity of diagnosis shifted from 'without metastatic infection' to 'uncertain for metastatic infection' and 'with metastatic infection' (P = 0.09). In multivariable analysis, independent factors associated with metastatic complications were suspicion of endocarditis in transthoracic echocardiography, clinical signs of metastatic infection, Pitt bacteraemia score ≥ 4, and persistent bacteraemia.

CONCLUSIONS

The new risk stratification system shows promise in predicting metastatic complications and guiding work-up and management of MRSAB. However, reducing the number of cases labelled as 'high-risk' and 'uncertain for metastatic infection' remains an area for improvement.

Quantitative and qualitative evaluation of antimicrobial usage: the first step for antimicrobial stewardship

The identification of antimicrobial use patterns is essential for determining key targets for antimicrobial stewardship interventions and evaluating the effectiveness thereof. Accurately identifying antimicrobial use patterns requires quantitative evaluation, which focuses on measuring the quantity and frequency of antimicrobial use, and qualitative evaluation, which assesses the appropriateness, effectiveness, and potential side effects of antimicrobial prescriptions. This paper summarizes the quantitative and qualitative methods used to evaluate antimicrobials, drawing insights from overseas and domestic cases.

Staphylococcus argenteus bacteremia in the Republic of Korea

In 2015, Staphylococcus argenteus and Staphylococcus schweitzeri were proposed as new species, distinct from Staphylococcus aureus and collectively referred to as the S. aureus complex. However, no clinical reports of these new species exist in Korea. Upon the application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for all bloodstream isolates since September 2022, S. argenteus was identified in one patient. Therefore, we aimed to search for new species among the archives of the S. aureus bacteremia cohort and describe their clinical and microbiological characteristics. Among the 691 archived S. aureus isolates between 2012 and 2018, one was identified as S. argenteus via MALDI-TOF MS. Both S. argenteus isolates (one in 2022) were obtained from patients with extensive pneumonia accompanied by bacteremia and both cases had fatal outcomes. They harbored multiple virulence genes (clfA, clfB, fnbpA, sdrC, sdrD, sdrE, bbp, cna, see, seg, sei, blaZ, fnbpB, and map) but did not harbor mecA and pvl. No matched sequence type (ST) was found in either isolate, and both S. argenteus isolates were closely related to ST1594, ST1593, ST1793, and ST1303, which belonged to S. argenteus. S. argenteus accounted for <1% of the S. aureus complex but had clinical characteristics similar to S. aureus. Therefore, clinicians should be aware of these factors to avoid misidentifying these strains as coagulase-negative staphylococci, and appropriate reporting is required to minimize confusion.IMPORTANCEStaphylococcus argenteus, a member of Staphylococcus aureus complex, has been reported as an important pathogen that causes clinically invasive infections in humans similar to S. aureus. Clinical isolates of S. argenteus have been reported across the world, showing a large geographical difference in prevalence and genomic profile. However, there have been no clinical reports regarding this new species in Korea. This is the first report to investigate the clinical and genetic characteristics of S. argenteus identified in patients with bacteremia, and the proportion of S. argenteus bacteremia among S. aureus bacteremia cohort in Korea.

Disease burden of bacteraemia with extended-spectrum beta-lactamase-producing and carbapenem-resistant Enterobacterales in Korea

BACKGROUND

Despite the significant impact of multi-drug-resistant bacteraemia, especially extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and carbapenem-resistant Enterobacterales (CRE), the burden of disease has not been investigated thoroughly.

AIM

To evaluate the clinical outcomes and socio-economic burden of ESBL-E and CRE bacteraemia nationwide in the Republic of Korea.

METHODS

A search was undertaken for all cases of ESBL-E and CRE bacteraemia and matched controls in 10 hospitals in the Republic of Korea over 6 months. Patients with ESBL-E or CRE bacteraemia were classified as the R group, and matched controls with antibiotic-susceptible bacteraemia and without infection were classified as the S and N groups, respectively. Patients' clinical data were collected, and the economic burden was estimated based on medical expenses, loss of productivity and total costs.

FINDINGS

In total, 795 patients were identified, including 265 patients with ESBL-E or CRE bacteraemia and their matched controls. The mean total length of stay for patients with ESBL-E and CRE in the R group was 1.53 and 1.90 times that of patients in the S group, respectively. The 90-day mortality rates for ESBL-E in the R and S groups were 12.1% and 5.6%, respectively, and the corresponding figures for CRE were 28.6% and 12.0%. There were significant differences in the total costs between the R, S and N groups for both ESBL-E and CRE (ESBL-E: $11,151 vs $8712 vs $6063, P=0.004; CRE: $40,464 vs $8748 vs $7279, P=0.024).

CONCLUSION

The clinical and economic burden imposed by ESBL-E or CRE bacteraemia was extremely high. These findings suggest that efforts to control resistant bacteraemia are necessary to reduce this burden.

False-positive results of galactomannan assays in patients administered glucose-containing solutions

Galactomannan (GM) is a polysaccharide cell wall component released by Aspergillus spp., and an immunoenzymatic GM assay is used for the diagnosis of invasive pulmonary aspergillosis. We evaluated the cause of strong positivity for GM in patients with no typical signs of aspergillosis. Repeat assays were performed using different instruments and reagent lots, but there were no differences in results among the assays. Patients with strongly positive GM results were investigated. Medication histories revealed that 14 of 23 patients had been administered total parenteral nutrition solution from one manufacturer and 4 patients had been administered dextrose solution from a different manufacturer before being tested. The results of GM assays conducted on samples of dextrose solution and the glucose fraction of the total parenteral nutrition solution were strongly positive, confirming the causes of the false-positive reactions. We hypothesize that a trace amount of GM was introduced into the glucose-containing solutions because glucoamylase, which is necessary for the saccharification step of glucose synthesis, was derived from Aspergillus niger. To enhance patient care and prevent unnecessary antifungal prescriptions, healthcare providers and manufacturers of healthcare products need to be aware of the possibility of false-positive reactions for GM.

Possibility of Decreasing Incidence of Human Immunodeficiency Virus Infection in Korea

BACKGROUND

The number of newly diagnosed cases of human immunodeficiency virus (HIV) infection in Korea, which had increased until 2019, has markedly decreased since the coronavirus disease 2019 pandemic started. This study evaluated whether the decrease is due to a reduction in the incidence of HIV infection and/or delayed diagnosis during the pandemic.

MATERIALS AND METHODS

We reviewed the medical records of 587 newly diagnosed patients with HIV infection between February 2018 and January 2022 from four general hospitals, and their characteristics were compared between the pre-pandemic and pandemic periods. The lapse time from infection to diagnosis was estimated using an HIV modeling tool.

RESULTS

The estimated mean times to diagnosis were 5.68 years (95% confidence interval [CI]: 4.45 - 6.51 years) and 5.41 years (95% CI: 4.09 - 7.03 years) before and during the pandemic, respectively (P = 0.016). The proportion of patients with acquired immunodeficiency syndrome-defining illnesses, expected to visit hospitals regardless of the pandemic, decreased from 17.2% before the pandemic to 11.9% during the pandemic (P = 0.086).

CONCLUSION

The decrease in the number of newly diagnosed cases of HIV infection in Korea might have resulted from an actual decrease in the incidence of HIV infection rather than a worsening of underdiagnosis or delayed diagnosis.

Developing a framework for regular and sustainable qualitative assessment of antibiotic use in Korean medical institutions: a Delphi study

BACKGROUND

We aimed to develop a roadmap for conducting regular, sustainable, and strategic qualitative assessments of antibiotic use in medical institutions within the Republic of Korea.

METHODS

A literature review on the current state of qualitative antibiotic assessments was conducted, followed by one open round to collect ideas, two scoring rounds to establish consensus, and one panel meeting between them. The expert panel comprised 20 experts in infectious disease or antibiotic stewardship.

RESULTS

The response rate for all three surveys was 95% (19/20), while the panel meeting attendance rate was 90% (18/20). The following long-term goals were defined to assess the annual use of antibacterial and antifungal agents in all medical institutions, including clinics. The panel agreed that random sampling of antibiotic prescriptions was the most suitable method of selecting antibiotics for qualitative assessment, with the additional possibility of evaluating specific antibiotics or infectious diseases that warrant closer evaluation for promoting appropriate antibiotic use. The plan for utilization of results from evaluation involves providing feedback while maintaining anonymity and disclosure. It includes a quantitative assessment of antibiotic prescriptions and resistance rates to compare against institutional benchmarks. Furthermore, it was agreed to link the evaluation findings to the national antibiotic stewardship programme, enabling policy and institutional approaches to address frequently misused items, identified during the evaluation.

CONCLUSION

This study provides a framework for establishing a qualitative assessment of antimicrobial use for medical institutions at a national level in the Republic of Korea.

Appropriateness of antibiotic use for patients with asymptomatic bacteriuria or urinary tract infection with positive urine culture: a retrospective observational multi-centre study in Korea

BACKGROUND

Antibiotic resistance threatens public health worldwide, and inappropriate use of antibiotics is one of the main causes.

AIM

To evaluate qualitative use of antibiotics in asymptomatic bacteriuria (ABU) and urinary tract infection (UTI).

METHODS

Cases of positive urine culture (≥105 colony-forning units/mL) performed in inpatient, outpatient and emergency departments in April 2021 were screened in 26 hospitals in the Republic of Korea. The cases were classified as ABU, lower UTI and upper UTI. The appropriateness of antibiotic use was evaluated retrospectively by infectious disease specialists using quality indicators based on clinical guidelines for ABU and UTI.

RESULTS

This study included a total of 2697 patients with ABU or UTI. The appropriateness of antibiotic use was assessed in 1157 patients with ABU, and in 677 and 863 patients with lower and upper UTI, respectively. Among the 1157 patients with ABU, 251 (22%) were prescribed antibiotics without appropriate indications. In 66 patients with ABU in which antibiotics were prescribed with appropriate indications, the duration was adequate in only 23 (34.8%) patients. The appropriateness of empirical and definite antibiotics was noted in 527 (77.8%) and 353 (68.0%) patients with lower UTI, and 745 (86.3%) and 583 (78.2%) patients with upper UTI, respectively. The duration of antibiotics was adequate in 321 (61.8%) patients with lower UTI and 576 (78.7%) patients with upper UTI.

CONCLUSIONS

This nationwide qualitative assessment of antibiotic use in ABU and UTI revealed that antibiotics were often prescribed inappropriately, and the duration of antibiotics was unnecessarily prolonged.

Applicability and limitations of quality indicator-based assessment of appropriateness in antimicrobial use: a comparison with expert opinion

BACKGROUND

The effective implementation of antimicrobial stewardship requires an a-priori assessment of the appropriateness of antimicrobial prescriptions.

AIM

To evaluate the effectiveness of quality indicators (QIs) in determining the appropriateness of antimicrobial prescriptions compared to that of expert opinions.

METHODS

The study assessed antimicrobial use in 20 hospitals in Korea, with infectious disease specialists rating the appropriateness based on QIs and expert opinions. The selected QIs were (1) taking two blood cultures, (2) taking cultures from suspected sites of infection, (3) prescribing empirical antimicrobials according to guidelines, and (4) changing from empirical to pathogen-directed therapy for hospitalized patients and (2, 3, and 4) for ambulatory patients. Applicability, compliance with QIs, and agreement between QIs and expert opinions were investigated.

FINDINGS

Overall, 7999 therapeutic uses of antimicrobials were investigated at the study hospitals. The experts rated 20.5% (1636/7999) as inappropriate use. For hospitalized patients, antimicrobial use was assessed based on all four QIs in 28.8% (1798/6234) of the cases. For ambulatory care patients, only 7.5% (102/1351) of the antimicrobial use cases were assessed using all three QIs. The agreement between expert opinions and all four QIs for hospitalized patients was minimal (κ = 0.332), whereas that between expert opinions and all three QIs for ambulatory patients was weak (κ = 0.598).

CONCLUSION

QIs have limitations in determining the appropriateness of antimicrobial use, and the degree of agreement with expert opinions was low. Therefore, these QI limitations should be considered when determining the appropriateness of antimicrobial use.

Antibiotic Prescription in Patients With Coronavirus Disease 2019: Analysis of National Health Insurance System Data in the Republic of Korea

BACKGROUND

Although coronavirus disease 2019 (COVID-19) is a viral infection, antibiotics are often prescribed due to concerns about accompanying bacterial infection. Therefore, we aimed to analyze the number of patients with COVID-19 who received antibiotic prescriptions, as well as factors that influenced antibiotics prescription, using the National Health Insurance System database.

METHODS

We retrospectively reviewed claims data for adults aged ≥ 19 years hospitalized for COVID-19 from December 1, 2019 to December 31, 2020. According to the National Institutes of Health guidelines for severity classification, we calculated the proportion of patients who received antibiotics and the number of days of therapy per 1,000 patient-days. Factors contributing to antibiotic use were determined using linear regression analysis. In addition, antibiotic prescription data for patients with influenza hospitalized from 2018 to 2021 were compared with those for patients with COVID-19, using an integrated database from Korea Disease Control and Prevention Agency-COVID19-National Health Insurance Service cohort (K-COV-N cohort), which was partially adjusted and obtained from October 2020 to December 2021.

RESULTS

Of the 55,228 patients, 46.6% were males, 55.9% were aged ≥ 50 years, and most patients (88.7%) had no underlying diseases. The majority (84.3%; n = 46,576) were classified as having mild-to-moderate illness, with 11.2% (n = 6,168) and 4.5% (n = 2,484) having severe and critical illness, respectively. Antibiotics were prescribed to 27.3% (n = 15,081) of the total study population, and to 73.8%, 87.6%, and 17.9% of patients with severe, critical, and mild-to-moderate illness, respectively. Fluoroquinolones were the most commonly prescribed antibiotics (15.1%; n = 8,348), followed by third-generation cephalosporins (10.4%; n = 5,729) and beta-lactam/beta-lactamase inhibitors (6.9%; n = 3,822). Older age, COVID-19 severity, and underlying medical conditions contributed significantly to antibiotic prescription requirement. The antibiotic use rate was higher in the influenza group (57.1%) than in the total COVID-19 patient group (21.2%), and higher in severe-to-critical COVID-19 cases (66.6%) than in influenza cases.

CONCLUSION

Although most patients with COVID-19 had mild to moderate illness, more than a quarter were prescribed antibiotics. Judicious use of antibiotics is necessary for patients with COVID-19, considering the severity of disease and risk of bacterial co-infection.

Anti-Alpha-Toxin Antibody Responses and Clinical Outcomes of Staphylococcus aureus Bacteremia

BACKGROUND

Alpha-toxin (AT), a major virulence factor of Staphylococcus aureus, is an important immunotherapeutic target to prevent or treat invasive S. aureus infections. Previous studies have suggested that anti-AT antibodies (Abs) may have a protective role against S. aureus bacteremia (SAB), but their function remains unclear. Therefore, we aimed to investigate the association between serum anti-AT Ab levels and clinical outcomes of SAB.

METHODS

Patients from a prospective SAB cohort at a tertiary-care medical center (n = 51) were enrolled in the study from July 2016 to January 2019. Patients without symptoms or signs of infection were enrolled as controls (n = 100). Blood samples were collected before the onset of SAB and at 2- and 4-weeks post-bacteremia. Anti-AT immunoglobin G (IgG) levels were measured using an enzyme-linked immunosorbent assay. All clinical S. aureus isolates were tested for the presence of hla using polymerase chain reaction.

RESULTS

Anti-AT IgG levels in patients with SAB before the onset of bacteremia did not differ significantly from those in non-infectious controls. Pre-bacteremic anti-AT IgG levels tended to be lower in patients with worse clinical outcomes (7-day mortality, persistent bacteremia, metastatic infection, septic shock), although the differences were not statistically significant. Patients who needed intensive care unit care had significantly lower anti-AT IgG levels at 2 weeks post-bacteremia (P = 0.020).

CONCLUSION

The study findings suggest that lower anti-AT Ab responses before and during SAB, reflective of immune dysfunction, are associated with more severe clinical presentations of infection.

Case Report and Literature Review of Occupational Transmission of Monkeypox Virus to Healthcare Workers, South Korea

We report a case of occupational monkeypox virus infection from a needlestick injury in a healthcare worker in South Korea and review similar reports in the literature during 2022. Postexposure prophylactic treatment with a third-generation smallpox vaccine and antiviral agent tecovirimat inhibited local virus spread and alleviated lesion pain.

Diagnostic Usefulness of Varicella Zoster Virus-Specific Immunoglobulin (Ig) A and IgG in Patients With Herpes Zoster

BACKGROUND

Whether varicella zoster virus (VZV) antibody titer could discriminate patients with herpes zoster (HZ) from healthy controls (HCs) is unclear. We evaluated the diagnostic usefulness of VZV-specific immunoglobulin A (IgA) and immunoglobulin G (IgG) antibodies in patients with confirmed HZ.

METHODS

Study subjects comprised patients with confirmed HZ by salivary VZV DNA positivity and control age- and sex-matched HCs. Saliva was collected and concurrent blood samples were obtained on the first visit day (acute phase) and after 4 weeks (convalescent phase) from 44 HZ patients. All 44 healthy volunteers provided blood and saliva samples once.

RESULTS

The median VZV IgA titers in acute-phase (5.2 mIU/mL, P < 0.001) and convalescent-phase (15.8 mIU/mL, P < 0.001) serum samples from HZ patients were significantly higher than those in HCs (1.35 mIU/mL). VZV IgA positivity was detected in about 20% of acute phase serum and convalescent-phase serum of HZ patients. The median VZV IgG antibody titers of HZ patients during acute (1,471.0 mIU/mL, P < 0.001) and convalescent (4,934.7 mIU/mL, P < 0.001) phases were significantly higher than the median titer reported for HCs (591.6 mIU/mL). A four-fold or higher increase in VZV IgG antibody titer was observed in 36.4% of HZ patients.

CONCLUSION

VZV IgA positivity or four-fold or higher increase in VZV IgG antibody titers were not detected in a satisfactory proportion of HZ-infected patients. However, the titer of VZV IgA or IgG antibody particularly in convalescent-phase sera may discriminate HZ patients from HCs.

1781. Antibiotic Prescription Trends of Patients with COVID-19: Analysis of National Health Insurance Data in Republic of Korea

Background

Although COVID-19 is a viral infection, it is known that antibiotics are often prescribed due to concerns about combined bacterial infection. Therefore, we aimed to analyze how many patients with COVID-19 received the antibiotic prescription as well as what kinds of factors contributed to it using the National Health Insurance database.

Methods

We retrospectively reviewed claims data for adults 19 years of age and older hospitalized for COVID-19 from December 1, 2019 to December 31, 2020. According to severity classification of the National Institutes of Health guidelines, we calculated not only the proportion of patients receiving antibiotics but also days of treatment per 1000 patient days. In addition, we investigated the factors contributing to antibiotic use by linear regression analysis.

Results

Of the 55,228 patients, 47% were male, 55% were older than 50 years of age, and most patients (89%) had no underlying diseases. The majority (84%, 46,576) were classified as having mild to moderate illness, with 11% (6,168) and 5% (2,484) having severe and critical, respectively. Antibiotics were prescribed in a total of 27% (15,081). While 74% of patients with severe illness and 88% of those with critical illness received antibiotic treatment, even 18% of mild to moderate cases were prescribed antibiotics. Fluoroquinolones were the most commonly prescribed antibiotics (8,348), followed by third generation cephalosporins (5,729) and beta-lactam/beta-lactamase inhibitors (3,822) as shown in Figure 1. Older age, severity of disease and underlying medical conditions contributed to overall prescription rates as well as days of antibiotic use significantly (Table 1).

Conclusion

Although most of COVID-19 patients had mild to moderate illness, more than a quarter were prescribed antibiotics. Judicious use of broad-spectrum antibiotics is necessary for COVID-19 patients, considering the severity of disease and the risk of bacterial co-infection.

Disclosures

All Authors: No reported disclosures.

208. Clinical outcomes of empirical versus pre-emptive broad spectrum antifungal therapy in patients with acute myelogenous leukemia receiving antimold prophylaxis

Background

Since antimold prophylaxis has been widely used in induction chemotherapy for acute myelogenous leukemia (AML), it should be re-evaluated whether broad spectrum antifungal therapy should be empirically used in prolonged febrile neutropenia. Therefore, we compared clinical outcomes of empirical versus pre-emptive antifungal therapy in patients with AML receiving antimold prophylaxis.

Methods

From September 2016 to December 2020, all adult AML patients (≥ 18 years) receiving antimold prophylaxis who had febrile neutropenia for ≥ 4 days during induction or re-induction chemotherapy at Seoul National University Hospital were retrospectively reviewed. They were classified into the empirical group (therapeutic broad spectrum antifungal agents had been used without evidence of invasive fungal infection [IFI]) or the pre-emptive group (antimold prophylaxis had been maintained until the emergence of IFI’s evidence). We compared clinical outcomes between the two groups after propensity score matching.

Results

A total of 229 chemotherapy episodes, 36 in the empirical group and 193 in the pre-emptive group, were analyzed. In the pre-emptive group, broad spectrum antifungal therapy was administered in 45 (23.3%) episodes. After 1:3 matching with age, gender, induction or re-induction chemotherapy, and worst qSOFA score at febrile neutropenia, incidence of proven or probable IFI (0/36 [0%] in the empirical group vs. 5/97 [5.2%] in the pre-emptive group, P=0.323) and all-cause mortality (3/36 [8.3%] in the empirical group vs. 4/97 [4.1%] in the pre-emptive group, P=0.388) were not different between the two groups.

Conclusion

Clinical outcomes of empirical versus pre-emptive broad spectrum antifungal therapy were comparable in patients with AML receiving antimold prophylaxis. Broad spectrum antifungal therapy could be delayed until the emergence of evidence of IFI, in the current era of antimold prophylaxis.

Disclosures

All Authors: No reported disclosures.

1783. Appropriateness of antibiotics use for patients with asymptomatic bacteriuria or urinary tract infection: A retrospective observational multicenter study in Korea

Background

Antibiotic resistance threatens public health worldwide, and inappropriate use of antibiotics is one of the main causes. Antibiotic use for asymptomatic bacteriuria (ABU) has been defined as “antibiotics never events”, and urinary tract infection (UTI) is one of the most common infectious diseases for which antibiotics are prescribed in Korea. To establish an effective antimicrobial stewardship strategy, a qualitative assessment of antibiotic use in actual clinical syndrome is necessary.

Methods

Cases of positive urine cultures (≥10⁵ CFU/ml), performed in inpatient, outpatient, and emergency departments in April 2021 were screened in 26 hospitals located throughout Korea. Cases were classified into ABU, lower UTI, and upper UTI. The appropriateness of antibiotic use was retrospectively evaluated by infectious disease specialists using quality indicators based on the domestic clinical guideline for ABU and UTI. Figure 1.

Prevalence of and factors associated with inappropriate Clostridioides difficile testing in a teaching hospital in Korea

Background

Given the increasing incidence of Clostridioides difficile infections in Korea, there has been an increase in inappropriate testing for C. difficile, which has rendered overdiagnosis of asymptomatic colonisers common. We aimed to investigate the appropriateness of C. difficile testing and the related factors.

Methods

We retrospectively reviewed the medical records of patients who were admitted to a 1300-bed tertiary-care teaching hospital in Korea and were tested for C. difficile infection from September 2019 to November 2019. We performed logistic regression analysis to investigate factors related to inappropriate testing. Further, a survey was conducted on physicians to assess the knowledge and ordering patterns of C. difficile testing.

Results

We included 715 tests from 520 patients in the analysis. Testing was classified as hospital-onset and community-onset and subclassified as appropriate and inappropriate following an algorithmic method. Among the 715 tests, 576 (80.6%) and 139 (19.6%) tests were classified as hospital-onset and community-onset, respectively. Among the hospital-onset tests, 297 (52%) were considered inappropriate. The risk of inappropriate testing increased when C. difficile tests were conducted in the emergency room (OR 24.96; 95% CI 3.12–199.98) but decreased in intensive care units (OR 0.36, 95% CI 0.19–0.67). The survey was conducted on 61 physicians. Internal medicine physicians had significantly higher scores than non-internal medicine physicians (7.1 vs. 5.7, p = 0.001). The most frequently ordered combination of tests was toxin + glutamate dehydrogenase (47.5%), which was consistent with the ordered tests.

Conclusion

Almost half of the C. difficile tests were performed inappropriately. The patient being located in the emergency room and intensive care unit increased and decreased the risk of inappropriate testing, respectively. In a questionnaire survey, we showed that internal medicine physicians were more knowledgeable about C. difficile testing than non-internal medicine physicians. There is a need to implement the diagnostic stewardship for C. difficile, especially through educational interventions for emergency room and non-internal medicine physicians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01111-0.

Current Status and Prospect of Qualitative Assessment of Antibiotics Prescriptions

Identifying inappropriately prescribed antibiotics for infectious diseases by monitoring the quality of antibiotics use is essential for effective implementation of antibiotic stewardship. Qualitative assessment of the use of antibiotics has been conducted in some countries, including Korea, since the 2000s. The qualitative assessment generally involves an assessment of each component of the antibiotics prescription process, based on specific criteria. However, there is no standardized assessment method or cycle, and infectious diseases or antibiotics included in the assessments vary from country-to-country. According to the results reported in the United States, Europe, Australia, and Korea so far, approximately 20 - 55% of all antibiotics prescriptions are inappropriate. In this review, we describe the current progress in the quality assessment of the use of antibiotics on a global scale. Further, we highlight the future directions to improve antibiotic stewardship activities and the quality assessment of the use of antibiotics in Korea.

Interspecies differences in clinical characteristics and risk factors for third-generation cephalosporin resistance between Escherichia coli and Klebsiella pneumoniae bloodstream infection in patients with liver cirrhosis

This retrospective study aimed to clarify the interspecies differences in the clinical characteristics and risk factors of bloodstream infection (BSI) due to third-generation cephalosporin-resistant (3GC-R) Escherichia coli (EC) and Klebsiella pneumoniae (KP) in patients with liver cirrhosis (LC). KP BSI had more comorbidities and higher treatment failure rate than EC BSI. Non-alcoholic LC was a risk factor for treatment failure in EC, whereas it was not associated with KP. Risk factors for BSI due to 3GC-R strain were nosocomial infection in EC, and β-lactam/fluoroquinolone treatment ≤ 30 days in KP. These results could help predict outcomes of BSI and improve clinical practice.

Prescriptions patterns and appropriateness of usage of antibiotics in non-teaching community hospitals in South Korea: a multicentre retrospective study

Background

Although non-teaching community hospitals form the majority of healthcare providers in South Korea, there is limited data on antibiotic usage in them. To evaluate the pattern of antibiotic usage and its appropriateness in hospitals with < 400 beds in South Korea.

Methods

A multicentre retrospective study was conducted in 10 hospitals (six long-term care hospitals, three acute care hospitals, and one orthopaedic hospital), with < 400 beds in South Korea. We analysed patterns of antibiotic prescription in 2019, and their appropriateness in the participating hospitals. For the evaluation of the appropriateness of the prescription, 25 patients under antibiotic therapy were randomly selected at each hospital, over two separate periods. Due to the heterogeneity of their characteristics, the orthopaedics hospital was excluded from the analysis.

Results

The most commonly prescribed antibiotics in long-term care hospitals was fluoroquinolone, followed by beta-lactam/beta-lactamase inhibitor (anti-pseudomonal). In acute care hospitals, these were third generation cephalosporin, followed by first generation cephalosporin, and second generation cephalosporin. The major antibiotics that were prescribed in the orthopedics hospital was first generation cephalosporin Only 2.3% of the antibiotics were administered inappropriately. In comparison, 15.3% of patients were prescribed an inappropriate dose. The proportion of inappropriate antibiotic prescriptions was 30.6% of the total antibiotic prescriptions.

Conclusions

The antibiotic usage patterns vary between non-teaching community hospitals in South Korea. The proportion of inappropriate prescriptions exceeded 30% of the total antibiotic prescriptions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01082-2.

Comparative Genomic Analysis of the Human Variant of Methicillin-Resistant Staphylococcus aureus CC398 in Japan and Korea

Staphylococcus aureus clonal complex (CC) 398 is a major clonal type of livestock-associated methicillin-resistant S. aureus and comprise both a human variant and a livestock-associated variant. We have previously identified three sequence type (ST) 1232 strains from Japanese patients (THI2018-120 and N1195) and a Vietnamese patient (S36). In this study, we found an ST1232 strain in a Korean patient (BDH17) and compared the genomes of the ST1232 strains isolated in Korea and Japan. Whole-genome sequencing and a phylogenetic tree based on single nucleotide polymorphisms showed that all ST1232 strains were human variants of S. aureus CC398 and were similar to a common lineage of Southeast Asia. All strains carried ϕSa2, ϕSa3, and Tn554, which included Panton-Valentine leukocidin, immune evasion cluster, and antimicrobial resistance genes, respectively. THI2018-120 and N1195 carried slightly different staphylococcal cassette chromosome mec element from BDH17 due to the insertion of a IS30 family. In addition, the strains originating from Japanese patients possessed a unique genetic element, blaZ-Tn4001-Tn554 element. In this study, we found that the ST1232 strains isolated in Korea and Japan are genetically closely related to each other. However, presence of the unique genetic elements suggests that the strains originating from Japanese patients may have evolved independently in Japan.

Control of a nosocomial measles outbreak among previously vaccinated adults in a population with high vaccine coverage: Korea, 2019

We describe a measles outbreak among previously vaccinated healthcare workers (HCWs) and inpatients and the control measures implemented at a tertiary care hospital in 2019. Case-patients were laboratory-confirmed measles with throat swabs tested by quantitative polymerase chain reactions (PCR), during April-May 2019. Medical histories and documented immunization records were obtained. We compared attack rates (ARs) among HCWs by occupational subgroup and age and examined the outbreak-associated costs. The index case was not ascertained. Among 26 measles case-patients (22 HCWs, four inpatients) aged 18-28 years, 25 had previously received measles-mumps-rubella (MMR) vaccine (12/26, 46% (two doses); 13/26, 50% (one dose)), and 16 (62%) had positive results of measles IgG prior to measles diagnosis. ARs were higher among HCWs aged < 30 years (1.88%), especially in the subgroup under 25 years of age (2.22%). Control measures included work restrictions for seronegative HCWs (218/2320, 9.4%) in immunity verification, administration of the MMR vaccine (207 HCWs) or intravenous immunoglobulin (2 HCWs and 11 inpatients), enhanced health surveillance of HCWs, and mandatory assessment of patients with measles-like symptoms at the infectious diseases screening units. The hospital spent 90,417,132 Korean won (US $79,733) in response to the outbreak. Measles outbreaks can occur in healthcare settings despite high population immunity, highlighting the importance of stronger vaccination policies, particularly among young HCWs. Moreover, an effective outbreak response comprising immunization activities and enhanced surveillance of HCWs and patients to rapidly detect measles-like symptoms at a prodromal phase is essential to control nosocomial measles outbreaks.

Are the Current Guidelines Sufficient to Establish Infection Control Strategies for COVID-19 Related Issues in Hospitals?

As hospitals cater to elderly and vulnerable patients, a high mortality rate is expected if a coronavirus disease 2019 (COVID-19) outbreak occurs. Consequently, policies to prevent the spread of COVID-19 in hospital settings are essential. This study was conducted to investigate how effectively national and international guidelines provide recommendations for infection control issues in hospitals. After selecting important issues in infection control, we performed a systematic review and analysis of recommendations and guidelines for preventing COVID-19 transmission within medical institutions at national and international levels. We analyzed guidelines from the World Health Organization, Centers for Disease Control and Prevention, European Centre for Disease Prevention and Control, and Korea Disease Control and Prevention Agency. Recent guidelines do not provide specific solutions to infection control issues. Therefore, efforts need to be made to devise consistent advice and guidelines for COVID-19 control.

430. Strategies for Prevention of COVID-19 Transmission in Hospitals

Background

Infection control measures against the coronavirus disease 2019 (COVID-19) within a hospital often rely on expert experience and intuition due to the lack of clear guidelines. This study surveyed current strategies for the prevention of the spread of COVID-19 in medical institutions.

Methods

Upon systematic review of the guidelines at the national level, 14 key topics were selected. Six hospitals were provided an open survey that assessed their responses to these topics between August 11 and 25, 2020. Using these data, an online questionnaire was developed and sent to the infection control teams of 46 hospitals in South Korea. The survey was conducted between January 31, 2021, and February 20, 2021.

Results

All 46 hospitals responded to the survey, and 24 hospitals (52.2%) had treated 100 or more cases of COVID-19. All hospitals operated screening clinics, and the criteria were respiratory symptoms (100%), fever (97.8%), and epidemiological association (93.5%). It was found that 89.1% (41/46) of hospitals allowed symptomatic patients to visit their general outpatient clinics if fever or respiratory symptoms were not associated with COVID-19. Most hospitals (87.2%; 34/39) conducted polymerase chain reaction (PCR) tests for all hospitalized patients. Moreover, 76.1% (35/46) of hospitals implemented preemptive isolation policies for hospitalized patients, of which 97.1% (34/35) were released from isolation after a single negative PCR test. A little over half of the hospitals (58.7%; 27/46) treated patients that met the national criteria for release from isolation but consistently had positive PCR results. Of these hospitals, 63% (17/27) used N95/KF94 masks, and 40.7% (11/27) used surgical masks without other personal protective equipment for treating them. Most hospitals (76.9%; 20/26) accommodated them in shared rooms when the cycle threshold value of the PCR test was more than a certain value (34.6%; 9/26), or after a certain period that satisfied the national criteria (26.9%; 7/26). Finally, 76.1% (35/46) of hospitals performed emergency procedures or operations on suspected patients.

Table 1. Screening and selective treatment policy to prevent COVID-19 patients from entering the hospital

Note

Values are presented as number (%) Abbreviations: COVID-19, coronavirus disease 2019; PCR, polymerase chain reaction 1 This question requested the respondent to select multiple items. 2 Suspected cases of COVID-19 include fever, respiratory symptoms, and epidemiological associations with COVID-19 patients.

Note

Values are presented as number (%) Abbreviations: COVID-19, coronavirus disease 2019; PCR, polymerase chain reaction; PAPR, powered air-purifying respirator; Ct, cycle threshold 1 This question requested the respondent to select multiple items. 2 It includes infectious diseases, pulmonology, and the infection control and prevention office. 3 One hospital that wrote a non-categorical answer for the question was excluded. The hospital made a decision after discussing it with an infectious diseases specialist.

Conclusion

Various guidelines were being applied by each medical institution, but there was a lack of an explicit set of national guidelines to support them.

Disclosures

All Authors: No reported disclosures

Status of antimicrobial stewardship programmes in Korean hospitals including small to medium-sized hospitals and the awareness and demands of physicians: a nationwide survey in 2020

OBJECTIVES

This study aimed to identify the status of antimicrobial stewardship programmes (ASPs) in small to medium-sized Korean hospitals as well as the awareness and demands about ASPs of physicians.

METHODS

A questionnaire was designed based on a questionnaire from a previous nationwide survey in 2018 targeting large hospitals in Korea and modified to reflect the results of in-depth interviews with non-infectious diseases (IDs) physicians at secondary care hospitals. The survey targeted all hospitals with ≥150 beds in South Korea and was performed in May-June 2020. Only one ASP-associated physician per hospital participated in the survey.

RESULTS

The survey response rate was 31.9% (217/680). ID specialists comprised the majority of medical personnel participating in ASPs in tertiary care hospitals. Conversely, in secondary and primary care hospitals there was no predominant medical personnel for ASPs and the median full-time equivalent was 0 for all types of medical personnel. Tertiary care hospitals, more than secondary and primary care hospitals, tended to perform ASP activities more actively. 'Workforce for ASPs', 'Establishment of healthcare fees for ASPs' and 'Development of tools for ASPs' were the most important required support for ASP improvement.

CONCLUSION

The level of ASP establishment was more limited in primary care hospitals than in secondary and tertiary care hospitals in Korea. To improve ASPs in Korean hospitals, a supporting workforce and the establishment of a healthcare fee for ASPs appear to be necessary.

Ongoing outbreak of human adenovirus-associated acute respiratory illness in the Republic of Korea military, 2013 to 2018

BACKGROUND/AIMS

Human adenovirus type 55 (HAdV-55), an emerging epidemic strain, has caused several large outbreaks in the Korean military since 2014, and HAdV-associated acute respiratory illness (HAdV-ARI) has been continuously reported thereafter.

METHODS

To evaluate the epidemiologic characteristics of HAdV-ARI in the Korean military, we analyzed respiratory virus polymerase chain reaction (RV-PCR) results, pneumonia surveillance results, and severe HAdV cases from all 14 Korean military hospitals from January 2013 to May 2018 and compared these data with nationwide RV surveillance data for the civilian population.

RESULTS

A total of 14,630 RV-PCRs was performed at military hospitals. HAdV (45.4%) was the most frequently detected RV, followed by human rhinovirus (12.3%) and influenza virus (6.3%). The percentage of the military positive for HAdV was significantly greater than the percentage of civilians positive for HAdV throughout the study period, with a large outbreak occurring during the winter to spring of 2014 to 2015. The outbreak continued until the end of the study, and non-seasonal detections increased over time. The reported number of pneumonia patients also increased during the outbreak. Case fatality rate was 0.075% overall but 15.6% in patients with respiratory failure. The proportion of severe patients did not change significantly during the study period.

CONCLUSION

A large HAdV outbreak is currently ongoing in the Korean military, with a trend away from seasonality, and HAdV-55 is likely the predominant strain. Persistent efforts to control the outbreak, HAdV type-specific surveillance, and vaccine development are required.

81. Physicians’ Knowledge, Attitude, and Practice regarding Prolonged Antimicrobial Use

Background

To reduce unnecessary long-term antibiotic therapies, pharmacist-led intervention followed by the involvement of infectious diseases (ID) specialist was implemented. In addition, a survey for the prescribers was conducted to find the gaps for improvement.

Methods

The “less is better” intervention was implemented between August 1, 2018 and February 28, 2019, which was focused on those to whom antibiotics had been administered for over 15 days. However, the following patients were excluded: patients having hematologic diseases, patients in the neonatal intensive care units, and patients who were recommended to maintain antibiotics by ID specialist. Treatment duration according to the indications was compared between pre-intervention period (Aug to Sep 2017) and post-intervention period. A questionnaire based on clinical vignettes was distributed among 140 prescribers.

Results

Among 500 prescriptions assessed as a prolonged treatment, 475 (95%) were stopped after intervention. Over the pre- and post-intervention period, pneumonia was the most common indication of prolonged antibiotic use (43.8 versus 43.0%). The treatment durations decreased from 21.0 (interquartile range [IQR], 27.3-18.0) days pre-intervention to 16.0 (IQR, 20.0-15.0) days post-intervention (p=0.000).

The survey response rate was 76.4% (107/140). Regarding community-acquired pneumonia, there was a significant difference between knowledge and practice, showing that 53% were aware of the standard duration, but 72% actually prescribed for a longer duration. There was a similar trend for the treatment of urinary tract infection (30% versus 83%, p=0.024). The reasons why the physicians prescribed antibiotics of a prolonged duration in spite of adequate knowledge were not only the lack of symptom alleviation in patients but also organizational factors.

Conclusion

The duration of long-term antibiotic treatment was shortened by active participation of pharmacist as well as ID specialists. However, gaps between the knowledge and practice on the duration of antibiotic treatment were also found. Therefore, it is necessary to implement appropriate feedback and education based on clinical scenario in order to improve the physicians’ antibiotic prescription.

Disclosures

All Authors: No reported disclosures

170. Development of Key Indicators for Appropriate Antibiotic Use in Republic of Korea: a Systematic Review followed by Delphi Procedure

Background

The aim of this study was to develop a set of key quality indicators (QIs) for application to nationwide point surveillance of appropriateness of antibiotic usage in Republic of Korea.

Methods

A systematic literature review was performed in order to retrieve a list of potential key QIs. These candidates were evaluated by multidisciplinary expert panel using a RAND-modified Delphi procedure, using two online questionnaires and a face-to-face meeting between them. Twenty-five expert panels with diverse backgrounds (infectious diseases specialist, urologist, laboratory medicine doctors, pediatric infectious disease specialists, otorhinolaryngology doctors, gastrointestinal doctors, pulmonologist, general surgeon, and researcher in National Evidence-Based Healthcare Collaborating Agency) participated in the consensus procedure. A Likert scale (ranging 1–7) was used for the evaluation of appropriateness of the potential key QIs and items with median score 6 or 7 were accepted if there was no disagreement. In addition, we grade each QI into admission, outward, or surgical prophylaxis using the Likert scale. If the score was 6 or 7, we considered it as appropriate application.

Results

The systematic literature review identified 23 potential QIs, from 21 studies. Ultimately, 17 key indicators were retained, with a high level of agreement (13 QIs for admitted patients, 7 for outward patients and 3 for surgical prophylaxis) (Figue 1). After sum of importance score and applicability, 6 key QIs [6 QIs (1–6) for admitted patients and 3 (1, 2 and 5) for outward patients] were finally selected: (1) prescribe empirical antibiotic therapy according to guideline, (2) change empirical to pathogen-directed therapy, (3) take cultures from suspected sites of infection, (4) take 2 blood cultures, (5) adapt antibiotic dosage to renal function, and (6) document antibiotic plan (Table 1). In surgical prophylaxis, prescribe according to guideline and initiate antibiotics one hour before incision was finally selected (Table 2).

Figure 1. Flowchart of the study

Table 1. Ranking in key indicators for admitted and out patients and applicability in point surveillance study.

Table 2. Ranking in key indicators for surgical prophylaxis and applicability in point surveillance study.

Conclusion

We identified key QIs to measure the appropriateness of antibiotics. These QIs can be used to identify targets for improvement and to evaluate the effects of antibiotic stewardship intervention.

Disclosures

All Authors: No reported disclosures

1605. Differences in Clinical Characteristics of Third Generation Cephalosporin Resistance and Treatment Outcomes in Escherichia coli and Klebsiella pneumoniae Bacteremia in Patients with Liver Cirrhosis

Background

This study aimed to identify characteristics of third-generation cephalosporin (3GC) resistance in Escherichia coli bateremia (ECB) and Klebsiella pneumoniae bacteremia (KPB) in patients with liver cirrhosis (LC), and to investigate the effects of appropriateness of empirical antibiotic treatment on outcomes.

Methods

We retrospectively collected demographic, clinical and microbiological information on all ECB and KPB episodes in LC patients ≥ 18 years of age hospitalized to a tertiary-care teaching hospital in South Korea from 2007 to 2018. Clinical characteristics associated with 3GC resistance and treatment failure were analyzed using a multivariate logistic regression model. Treatment failure was defined as persistent bacteremia for ≥ 7 days, or relapsed bacteremia ≤ 30 days, or all-cause mortality ≤ 30 days.

Results

3GC resistance rates of E. coli were 30.3% overall and increased significantly during the study period (P=0.001), while the rates of K. pneumoniae were not changed (24.3% overall) (P=0.994). Of total 356 ECB and KPB episodes, 112 were caused by 3GC resistant strains. The factor associated with 3GC resistance was isolation of 3GC resistant strain ≤ 1 year in both ECB (OR, 7.754; 95% CI, 2.094~28.716) and KPB (OR, 2.774; 1.318~5.838). In ECB, beta-lactam or fluoroquinolone treatment ≤ 30 days was another factor associated with 3GC resistance (OR, 2.774; 95% CI, 1.318~5.838), but not in KPB. The factor associated with treatment failure was high MELD score in both ECB (OR, 1.193 at 1 increase; 95% CI, 1.118~1.272) and KPB (OR, 1.163; 95% CI 1.083~1.250). Additionally, in ECB, non-alcoholic LC (OR 3.262; 95% CI 1.058~10.063), high Charlson Comorbidity Index (OR, 1.285; 95% CI 1.066~1.548), and inappropriate empirical antibiotic treatment (OR, 3.194; 95% CI 1.207~8.447) were associated with treatment failure.

Conclusion

During the study period, 3GC resistance increased in ECB, but not in KPB. In ECB, the severity of the underlying disease and the appropriateness of empirical antibiotics were associated with treatment failure, but there was no correlation in KPB. In ECB of LC patients, the appropriateness of empirical antibiotics was a factor associated with treatment outcome, and is the only correctable factor in the clinical setting.

Disclosures

All Authors: No reported disclosures

Recovery of Tenofovir-induced Nephrotoxicity following Switch from Tenofovir Disoproxil Fumarate to Tenofovir Alafenamide in Human Immunodeficiency Virus-Positive Patients

Background

Tenofovir disoproxil fumarate (TDF)-induced nephrotoxicity is related to high plasma tenofovir concentrations. Tenofovir alafenamide (TAF) is a tenofovir prodrug with 90% lower plasma tenofovir concentrations. The aim of this study was to evaluate changes in tenofovir-induced nephrotoxicity in Human Immunodeficiency Virus (HIV)-positive patients who switched from TDF to TAF.

Materials and Methods

We identified all HIV-positive patients who switched from elvitegravir/cobicistat/emtricitabine/TDF to elvitegravir/cobicistat/emtricitabine/TAF at a tertiary hospital. We assessed tubulopathy and renal dysfunction before TDF administration, at the time TAF was used following at least 3 months of TDF use, and 3 months after TAF administration. Tubulopathy was defined by the presence of at least three abnormalities in fractional excretion of phosphate, fractional excretion of uric acid, urinary β2-microglobulin, urinary N-acetyl-β-D-glucosaminidase, glucosuria or proteinuria. Renal dysfunction was defined as decreased by more than 25% in the estimated glomerular filtration rate (eGFR) relative to baseline.

Results

In 80 patients, the mean eGFR was 96.8 mL/min/1.73 m² before administration of TDF, 81.2 (P <0.001) at the time of change to TAF, 90.9 (P <0.001) after TAF administration. Renal dysfunction occurred in 19 patients (23.8%) after TDF use for a median 15 months, 11 (57.9%) of these patients recovered from renal dysfunction after TAF administration. Six patients (7.5%) had tubulopathy before TDF administration, 36 (45.0%) after TDF administration (P <0.001), 12 (15.0%) after TAF administration (P = 0.002).

Conclusion

Tenofovir-induced nephrotoxicity in HIV-positive patients receiving TDF was mostly reversible after changing to TAF. Thus, TAF-containing regimens can be administered safely to HIV-positive patients with tenofovir-induced nephrotoxicity.

Clinical Score System to Differentiate Severe Fever with Thrombocytopenia Syndrome Patients from Patients with Scrub Typhus or Hemorrhagic Fever with Renal Syndrome in Korea

BACKGROUND

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high mortality in East Asia. This study aimed to develop, for primary care providers, a prediction score using initial symptoms and basic laboratory blood tests to differentiate between SFTS and other endemic zoonoses in Korea.

METHODS

Patients aged ≥ 18 years diagnosed with endemic zoonoses during a 3-year period (between January 2015 and December 2017) were retrospectively enrolled from 4 tertiary university hospitals. A prediction score was built based on multivariate logistic regression analyses.

RESULTS

Of 84 patients, 35 with SFTS and 49 with other endemic zoonoses were enrolled. In multivariate logistic regression analysis, independent predictors of SFTS included neurologic symptoms (odds ratio [OR], 12.915; 95% confidence interval [CI], 2.173-76.747), diarrhea (OR, 10.306; 95% CI, 1.588-66.895), leukopenia (< 4,000/mm³) (OR, 19.400; 95% CI, 3.290-114.408), and normal C-reactive protein (< 0.5 mg/dL) (OR, 24.739; 95% CI, 1.812-337.742). We set up a prediction score by assigning one point to each of these four predictors. A score of ≥ 2 had 82.9% sensitivity (95% CI, 71.7%-87.5%) and 95.9% specificity (95% CI, 88.0%-99.2%). The area under the curve of the clinical prediction score was 0.950 (95% CI, 0.903-0.997).

CONCLUSION

This study finding suggests a simple and useful scoring system to predict SFTS in patients with endemic zoonoses. We expect this strategic approach to facilitate early differentiation of SFTS from other endemic zoonoses, especially by primary care providers, and to improve the clinical outcomes.

Delays in Isolating Patients Admitted to Hospital with Pulmonary Tuberculosis in Korea

BACKGROUND

Delays in isolating patients admitted to hospital with active pulmonary tuberculosis (PTB) can contribute to nosocomial transmission; however, in Korea, patients with clinically diagnosed PTB are not routinely isolated while awaiting microbiological confirmation of the diagnosis. We aimed to assess the extent of delays in isolating patients admitted with PTB and to identify the factors associated with delayed isolation.

METHODS

We retrospectively reviewed the electronic medical records of patients aged ≥ 18 years with active PTB, between January 2008 and December 2017, from two Korean hospitals.

RESULTS

Among 1,062 patients, 612 (57.6%) were not isolated on admission day. The median time from admission to isolation was 1 day (interquartile range: 0-2 days). The independent risk factor most strongly associated with delayed isolation was admission to departments other than pulmonology or infectious diseases departments (adjusted odds ratio [aOR], 5.302; 95% confidence interval [CI], 3.177-8.847; P < 0.001). Factors associated with isolation on admission day were a past history of tuberculosis (TB) (aOR, 0.669; 95% CI, 0.494-0.906; P = 0.009), night sweats (aOR, 0.530; 95% CI, 0.330-0.851; P = 0.009), and apical infiltrates on chest radiographs (aOR, 0.452; 95% CI, 0.276-0.740; P = 0.002).

CONCLUSION

Concerning patients subsequently diagnosed with active PTB, > 50% were not isolated on admission day. We suggest that the patients with clinically suspected PTB including the elderly who have a past history of TB, night sweats, or apical infiltration on chest radiographs, be presumptively isolated on admission, without waiting for microbiological confirmation of the diagnosis.

Immunogenicity of Influenza Vaccination in Patients with Cancer Receiving Immune Checkpoint Inhibitors

Among prospectively enrolled adult patients with cancer receiving immune checkpoint inhibitors (ICIs; n = 46) or cytotoxic agents (n = 90), seroprotection and seroconversion rates after seasonal quadrivalent influenza vaccinations were higher with ICI than with cytotoxic chemotherapy. These results support annual influenza vaccinations for cancer patients receiving ICIs.

Clinical Trials Registration clinicaltrials.gov (NCT03590808).

238. Direct identification of Bacterial Species with MinION Nanopore Sequencer In Clinical Specimens Suspected of Polybacterial Infection

Background

Conventional culture tests usually identify only a few bacterial species, which can grow well in the culture system, in the cases of polybacterial infection. 16S rRNA gene nanopore sequencing enables semi-quantitative identification of bacterial genetic materials. We aimed to evaluate usefulness of 16s rRNA gene nanopore sequencing in the cases suspected of polybacterial infection.

Methods

The research was conducted in a single university hospital for one year. Conventional bacterial culture identification and nanopore sequencing of 16s rRNA gene were carried out simultaneously for cases where polybacterial infection is strongly suspected. Blood agar plate was used for conventional culture, and Microscan (Beckman Coulter, United States) and Vitek 2 (Biomerieux, FR) automated systems were used for identification. For nanopore sequencing, 16S rRNA gene PCR was performed from the clinical specimens, and sequencing libraries were generated from the PCR products using the rapid barcoding sequencing kit (Oxford nanopore technologies, UK). MinION sequencing was performed for 1–3 hours and the generated reads were analyzed using the EPI2ME 16S BLAST workflow.

Results

Specimens were obtained from 15 patients; 6 liver abscess, 2 psoas abscess, 2 thigh abcess, 1 paraspinal abscess, 1 mycotic aneurysm, 1 necrotizing fasciitis, 1 fingertip gangrene and 1 abscess in coccyx area. 16s rRNA gene nanopore sequencing showed monobacterial organism in 8 (53.3%) specimens and polybacterial organisms in 7 (46.6%) specimens. In three (37.5%) cases of 8 cases with monobacterial infections identified by 16s rRNA gene sequencing, no organism was grown in conventional culture, possibly due to previous antibiotic administration. Notably, among 8 cases with polybacterial infection by 16s rRNA gene nanopore sequencing test, traditional culture test showed polybacterial infection in only two (25%) cases and single bacterial organism was identified in the other 6 (75%) cases.

Conclusion

Nanopore sequencing of 16s rRNA gene using the MinION sequencer may be useful for identification of causing microorganism and differentiation between monobacterial and polybacterial infection when polybacterial infection is suspected.

Disclosures

All authors: No reported disclosures.

2026. A Current Status of Antimicrobial Stewardship Programs in Korean Large Hospitals: A Nationwide Survey in 2018

Background

The aim of this study was to examine the current status of antimicrobial stewardship program (ASP) in large hospitals in South Korea, identifying problems and hurdles for implementation of proper ASP, and providing a reference for the proposal of ASP policies.

Methods

The questionnaire was designed based on the “Seven Core Elements of Hospital Antibiotic Stewardship Programs” from Centers for Diseases Control and Prevention of the U.S. and modified from the questionnaire of the previous survey on ASP in Korea, 2015. The survey targeted all the hospitals with 500 beds or more in South Korea in 2018. The online-based survey using SurveyMonkey^® platform was conducted for 3 weeks from June to July 2018. Only one ASP-associated physician per hospital participated in the survey.

Results

The response rate to the survey was 88.4% (84/95). The median number of medical personnel participating in ASP was 4 [interquartile range (IQR) 2.25–5], most of which were infectious diseases specialists (median 2, IQR 1–2). Besides, some pediatric infectious diseases specialists, pharmacists, etc. were participating in the ASPs. Only 6.0% (5/84) of hospitals had full-time workers for ASP. Restrictive measures for designated antibiotics was a widely accepted ASP strategy among Korean hospitals (88.1%, 74/84) and the median number of designated antibiotic classes was 16 (IQR 11–19). An 11.9% (10/84) of hospitals introduced monitoring and intervention program against inappropriate antibiotic combination therapy. The proportion of hospitals which had interventions for inappropriate long-term antibiotic use and parenteral to oral conversion strategy were 9.5% (8/84) and 1.2% (1/84), respectively. Lack of time, personnel, and appropriate reward were perceived as the major barriers to establishing ASP in Korean hospitals.

Conclusion

ASP in Korean hospitals were mainly carried out by 1–2 infectious diseases specialists and it heavily depended on restrictive measures for designated antibiotics. Supporting manpower and establishment of the appropriate reward system is necessary for improvement of ASP in Korean hospitals.

Disclosures

All authors: No reported disclosures.

116. Risk Factors and Clinical Outcomes of Carbapenem Non-Susceptible Gram-Negative Bacteremia in Patients with Acute Myelogenous Leukemia

Background

Early administration of susceptible antibiotics is crucial in Gram-negative bacteremia (GNB), especially in immunocompromised patients. We aimed to explore risk factors and clinical outcomes of carbapenem non-susceptible (Carba-NS) GNB in patients with acute myelogenous leukemia (AML).

Methods

Cases of all GNB during induction or consolidation chemotherapy for AML in a 15-year period in a tertiary hospital were retrospectively reviewed. Independent risk factors for Carba-NS GNB were sought and its clinical outcomes were compared with those of carbapenem susceptible (Carba-S) GNB.

Results

Among 485 GNB cases from 930 patients, 440 (91%) were Carba-S and 45 (9%) were Carba-NS GNB. Frequent Carba-NS isolates were Stenotrophomonas maltophilia (n = 23), Pseudomonas aeruginosa (n = 11), and Acinetobacter baumannii (n = 10). Independent risk factors for Carba-NS GNB were carbapenem use at the onset of GNB (aOR [95% CI], 78.6 [24.4–252.8]; P < 0.001), the isolation of imipenem-resistant A. baumannii in the prior 1 year (aOR [95% CI], 14.6 [2.7–79.9]; P = 0.002), time interval from chemotherapy to GNB ≥20 days (aOR [95% CI], 4.7 [1.7–13.1]; P = 0.003), and length of hospital stay ≥30 days (aOR [95% CI], 3.4 [1.3–9.1]; P = 0.013). Except breakthrough GNBs which occurred during carbapenem treatment, the frequency of Carba-NS GNB was 48% (19/40) in cases having ≥2 risk factors other than carbapenem use. 30-day overall mortality (Carba-NS, 36% vs. Carba-S, 6%; P < 0.001) and in-hospital mortality (Carba-NS, 47% vs. Carba-S, 9%; P < 0.001) were significantly higher in Carba-NS GNB.

Conclusion

Carba-NS GNB in AML patients was independently associated with the use of carbapenem, the past isolation of resistant organism, and late onset of GNB, and its clinical outcomes were poorer than those of Carba-S GNB. Carba-NS organisms should be considered for antibiotic selection in AML patients having these risk factors.

Disclosures

All authors: No reported disclosures.

273. Low Positive Predictive Value of β-d-Glucan in Hematology Patients Receiving Antimold Prophylaxis

Background

Detection of β-D-glucan (BDG) in serum is recognized as the mycological evidence in the diagnosis of invasive fungal infection (IFI). However, its diagnostic value in low prevalence of IFI has not been elucidated. We aimed to examine the performance of BDG in hematology patients receiving antimold prophylaxis.

Methods

We retrospectively reviewed all BDG results performed for the purpose of diagnosis or surveillance for IFI in hematology patients receiving posaconazole or micafungin prophylaxis from January 2017 to February 2019 in a tertiary hospital. At least two consecutive positive results of BDG were regarded as positive BDG. All the episodes were classified into true-positive (TP, positive BDG with probable/proven IFI), true-negative (TN, negative BDG without probable/proven IFI), false-positive (FP, positive BDG without probable/proven IFI), false-negative (FN, negative BDG with probable/proven IFI), and nonevaluable (could not be determined for the occurrence of breakthrough IFI). When BDG test was performed in the setting of persistent fever ≥72 hours in spite of broad-spectrum antibiotics or with a suspicion of IFI, it was defined as a diagnostic BDG episode, while others were defined as a surveillance BDG episode.

Results

Of a total of 140 episodes, 24 episodes were non-evaluable. Among 116 evaluable episodes, 75 received induction chemotherapy for acute leukemia or myelodysplastic syndrome, 35 underwent stem cell transplantation, and 10 had intensive treatment for graft-vs.-host disease. There were three episodes of probable/proven IFI (2.6%). Ninety-one (78.4%) were performed with diagnostic purpose, while 25 (21.6%) were performed for surveillance. TP, TN, FP, and FN were 2 (1.7%), 91, 22, and 1, respectively. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value were 66.7%, 80.5%, 8.3% and 98.9%, respectively. PPV was 13.3% and 0% in diagnostic and surveillance BDG episodes, respectively.

Conclusion

The PPV of BDG was low in hematology patients receiving antimold prophylaxis, even in the diagnostic-driven episodes. The routine screening of BDG is not helpful, and the BDG test may be used for exclusion of IFI rather than for diagnosis in these patients.

Disclosures

All authors: No reported disclosures.

Protective Effectiveness of Inactivated Hantavirus Vaccine Against Hemorrhagic Fever With Renal Syndrome

As there is no effective treatment against hemorrhagic fever with renal syndrome (HFRS), the development of effective vaccine is important. An inactivated hantavirus vaccine (IHV) has been used in Korea, but there has been controversy regarding its effectiveness. We conducted a case-control study to evaluate the vaccine effectiveness (VE) of IHV against HFRS in the Korean military. Unadjusted and adjusted VEs of IHV were 59.1% and 58.9%, respectively. VE was higher in divisions with high incidence of HFRS (unadjusted VE, 71.4%; adjusted VE, 78.7%). Our study demonstrated the moderate effectiveness of IHV in high-risk populations residing in endemic area.

Therapeutic outcome of spinal implant infections caused by Staphylococcus aureus: A retrospective observational study

Spinal implant infection is a rare but significant complication of spinal fusion surgery, and the most common pathogen is Staphylococcus aureus. It is difficult to treat due to this pathogen's biofilm-forming ability and antibiotic resistance. We evaluated the therapeutic outcome of treatments for S aureus spinal implant infections. We retrospectively reviewed all patients with S aureus spinal implant infections at 11 tertiary-care hospitals over a 9-year period. Parameters predictive of treatment failure and recurrence were analyzed by Cox regression. Of the 102 patients with infections, 76 (75%) were caused by methicillin-resistant S aureus (MRSA) and 51 (50%) were late-onset infections. In all, 83 (81%) patients were managed by debridement, antibiotics, and implant retention (DAIR) and 19 (19%) had their implants removed. The median duration of all antibiotic therapies was 52 days. During a median follow-up period of 32 months, treatment failure occurred in 37 (36%) cases. The median time to treatment failure was 113 days, being <1 year in 30 (81%) patients. DAIR (adjusted hazard ratio [aHR], 6.27; P = .01) and MRSA infection (aHR, 4.07; P = .009) were independently associated with treatment failure. Rifampin-based combination treatments exhibited independent protective effects on recurrence (aHR, 0.23; P = .02). In conclusion, among patients with S aureus spinal implant infections, MRSA and DAIR were independent risk factors for treatment failure, and these risk factors were present in the majority of patients. In this difficult-to-treat population, the overall treatment failure rate was 36%; rifampin may improve the outcomes of patients with S aureus spinal implant infections.

Evaluation of Methicillin-Resistance Rates among Community-associated Staphylococcus aureus Infections in Korean Military Personnel

To evaluate methicillin-resistance (MR) rates among community-associated (CA) Staphylococcus aureus infections in the Korean military, we screened electronic medical records of 223 patients with S. aureus infection in a military referral hospital from 2012 to 2017. During the study period, MR rates did not change annually, and were not different between officers and conscripted personnel. Among conscripted personnel, MR rates in CA S. aureus infections did not increase with longer duration of military service, both in trend analysis and multivariate analysis. In conclusion, MR rates among CA S. aureus infections did not increase during military service in Korea.

Incidence and risk factors of postoperative pneumonia following cancer surgery in adult patients with selected solid cancer: results of "Cancer POP" study

The aim of this study was to investigate the incidence and risk factors of postoperative pneumonia (POP) within 1 year after cancer surgery in patients with the five most common cancers (gastric, colorectal, lung, breast cancer, and hepatocellular carcinoma [HCC]) in South Korea. This was a multicenter and retrospective cohort study performed at five nationwide cancer centers. The number of cancer patients in each center was allocated by the proportion of cancer surgery. Adult patients were randomly selected according to the allocated number, among those who underwent cancer surgery from January to December 2014 within 6 months after diagnosis of cancer. One‐year cumulative incidence of POP was estimated using Kaplan–Meier analysis. An univariable Cox's proportional hazard regression analysis was performed to identify risk factors for POP development. As a multivariable analysis, confounders were adjusted using multiple Cox's PH regression model. Among the total 2000 patients, the numbers of patients with gastric cancer, colorectal cancer, lung cancer, breast cancer, and HCC were 497 (25%), 525 (26%), 277 (14%), 552 (28%), and 149 (7%), respectively. Overall, the 1‐year cumulative incidence of POP was 2.0% (95% CI, 1.4–2.6). The 1‐year cumulative incidences in each cancer were as follows: lung 8.0%, gastric 1.8%, colorectal 1.0%, HCC 0.7%, and breast 0.4%. In multivariable analysis, older age, higher Charlson comorbidity index (CCI) score, ulcer disease, history of pneumonia, and smoking were related with POP development. In conclusions, the 1‐year cumulative incidence of POP in the five most common cancers was 2%. Older age, higher CCI scores, smoker, ulcer disease, and previous pneumonia history increased the risk of POP development in cancer patients.

Clinical Characteristics and Outcomes of Healthcare-Associated Hematogenous Vertebral Osteomyelitis

Background

The incidence of hematogenous vertebral osteomyelitis (HVO) has increased over recent years, likely due to longer life expectancies, higher prevalence of chronic disease, and more effective diagnostic techniques. Recently, healthcare-associated infections, such as catheter-related and procedure-related bloodstream infections, also increase the risk of HVO. The aim of our study was to evaluate the clinical characteristics and outcomes of healthcare-associated HVO (HCA-HVO).

Methods

We conducted a retrospective chart review of adult patients with microbiologically diagnosed HVO from five tertiary-care hospitals over 8-year period. HCA-HVO was defined as onset of symptoms after 1 month of hospitalization or within 6 months after hospital discharge, or ambulatory manipulations in the 6 months before the diagnosis [Pigrau et al. Medicine (Baltimore) 2015; 94:e365]. We compared the clinical characteristics and outcomes of HCA-HVO with community-acquired HVO (CA-HVO) cases.

Results

In total, 358 patients with microbiologically diagnosed HVO were included in final analysis. Of these 358 cases, 256 (63.1%) were CA-HVO and 132 (36.9%) were HCA-HVO according to the predefined criteria. The main causative pathogens identified were methicillin-susceptible Staphylococcus aureus (32%), followed by methicillin-resistant S. aureus (MRSA) (26%), aerobic gram-negative bacteria (24%), and Streptococcus species (11%). Compared with CA-HVO cases, patients with HCA-HVO had more neoplasm (13.6% vs. 5.8%, P = 0.01) and end-stage renal disease (8.3% vs. 2.2%, P = 0.007). MRSA was more frequent pathogens in HCA-HVO cases than in CA-HVO (37.1% vs. 17.7%, P = 0.01). Patients with HCA-HVO were more likely to be have the higher rates of persistent bacteremia for ≥7 days (24.2% vs. 15.5%, P = 0.04), 1-year mortality (18.2% vs. 11.5%, P = 0.08) and 1-year relapse (12.1% vs. 6.2%, P = 0.051).

Conclusion

In this study, more than one-third of HVO is health care associated. Patients with HCA-HVO were more likely to have underlying illness, and their causative pathogens were more frequently MRSA. Outcomes of HCA-HVO were poorer, which require prevention measures and early diagnosis.

Disclosures

All authors: No reported disclosures.

Epidemiology and Clinical Characteristics of Zika Virus Infections Imported into Korea from March to October 2016

Zika is a re-emerging, mosquito-borne viral infection, which has been recently shown to cause microcephaly and Guillain-Barré syndrome. Since 2015 the number of infected patients has increased significantly in South America. The purpose of this study was to identify the epidemiologic and clinical characteristics of patients with Zika virus (ZIKV) infections in Korea. Patients who had visited areas of risk and tested positive in the ZIKV reverse transcriptase polymerase chain reaction (RT-PCR) in blood, urine, or saliva specimens were included. The first Korean case of ZIKV infection was reported in March 2016, and 14 cases had been reported by October 2016. The median age of the patients was 34 years (19-64 years). Ten patients had been exposed in Southeast Asia and 4 in Latin America. Rash was the most common symptom (92.9%; 13/14), followed by myalgia (50.0%; 7/14), and arthralgia (28.6%, 4/14). There were no neurologic abnormalities and none of the patients was pregnant. Results of biochemical tests were normal. Positivity rates of RT-PCR for ZIKV in serum, urine, and saliva were 53.8%, 100.0%, and 83.3%, respectively in the first week of symptoms. In conclusion, 14 patients with ZIKV infections were reported in Korea by October 2016 and all of them had mild clinical symptoms.

Olecranon Osteomyelitis due to Actinomyces meyeri: Report of a Culture-Proven Case

Actinomyces meyeri is a Gram positive, strict anaerobic bacterium, which was first described by Meyer in 1911. Primary actinomycotic osteomyelitis is rare and primarily affects the cervicofacial region, including mandible. We present an unusual case of osteomyelitis of a long bone combined with myoabscess due to A. meyeri. A 70-year-old man was admitted for pain and pus discharge of the right elbow. Twenty-five days before admission, he had hit his elbow against a table. MRI of the elbow showed a partial tear of the distal triceps tendon and myositis. He underwent open debridement and partial bone resection for the osteomyelitis of the olecranon. Biopsy showed no sulfur granules, but acute and chronic osteomyelitis. The excised tissue grew A. meyeri and Peptoniphilus asaccharolyticus. Intravenous ceftriaxone was administered and switched to oral amoxicillin. Infection of the extremities of actinomycosis often poses diagnostic difficulties, but it should not be neglected even when the characteristic pathologic findings are not present.

Erratum: Nocardia Brain Abscess in an Immunocompetent Patient

[This corrects the article on p. 45 in vol. 46, PMID: 24693470.].