Initial and 5-day positivity rate of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) polymerase chain reaction (PCR) in exposed inpatients within shared rooms during the omicron-variant dominant period

In this observational study conducted in 2022, 12.3% of patients who shared a room with a patient positive for severe acute respiratory coronavirus virus 2 (SARS-CoV-2) also had a positive polymerase chain reaction (PCR) test, either at initial screening or during a 5-day quarantine. Therefore, screening and quarantine are still necessary within hospitals for close-contact inpatients during the SARS-CoV-2 omicron-variant dominant period.

Gender differences in psychosocial determinants of hand hygiene among physicians

OBJECTIVE

We investigated gender differences in psychosocial determinants that affect hand hygiene (HH) performance among physicians.

DESIGN

The survey included a structured questionnaire with 7 parts: self-assessment of HH execution rate; knowledge, attitude, and behavior regarding HH; internal and emotional motivation for better HH; barriers to HH; need for external reminders; preference for alcohol gel; and embarrassment due to supervision.

SETTING

The study was conducted across 4 academic referral hospitals in Korea.

PARTICIPANTS

Physicians who worked at these hospitals were surveyed.

METHODS

The survey questionnaire was sent to 994 physicians of the hospitals in July 2018 via email or paper. Differences in psychosocial determinants of HH among physicians were analyzed by gender using an independent t test or the Fisher exact test.

RESULTS

Of the 994 physicians, 201 (20.2%) responded to the survey. Among them, 129 (63.5%) were men. Male physicians identified 4 barriers as significant: time wasted on HH (P = .034); HH is not a habit (P = .004); often forgetting about HH situations (P = .002); and no disadvantage when I do not perform HH (P = .005). Female physicians identified pain and dryness of the hands as a significant obstacle (P = .010), and they had a higher tendency to feel uncomfortable when a fellow employee performed inadequate HH (P = .098). Among the respondents, 26.6% identified diversifying the types of hand sanitizers as their first choice for overcoming barriers to improving HH, followed by providing reminders (15.6%) and soap and paper towels in each hospital room (13.0%).

CONCLUSION

A significant difference in the barriers to HH existed between male and female physicians. Promoting HH activities could help increase HH compliance.

One-year antibody durability induced by EuCorVac-19, a liposome-displayed COVID-19 receptor binding domain subunit vaccine, in healthy Korean subjects

OBJECTIVE

EuCorVac-19 (ECV-19), an adjuvanted liposome-displayed receptor binding domain (RBD) COVID-19 vaccine, previously reported interim Phase 2 trial results showing induction of neutralizing antibodies 3 weeks after prime-boost immunization. The objective of this study was to determine the longer-term antibody response of the vaccine.

METHODS

To assess immunogenicity 6 and 12 months after vaccination, participants in the Phase 2 trial (NCT04783311) were excluded if they: 1) withdrew, 2) reported COVID-19 infection or additional vaccination, or 3) exhibited increasing Spike (S) antibodies (representing possible non-reported infection). Following exclusions, of the 197 initial subjects, anti-S IgG antibodies and neutralizing antibodies were further assessed in 124 subjects at the 6-month timepoint, and 36 subjects at the 12-month timepoint.

RESULTS

Median anti-S antibody half-life was 52 days (interquartile range [IQR]:42-70), in the "early" period from 3 weeks to 6 months, and 130 days (IQR:97-169) in the "late" period from 6 to 12 months. There was a negative correlation between initial antibody titer and half-life. Anti-S and neutralizing antibody responses were correlated. Neutralizing antibody responses showed longer half-lives; the early period had a median half-life of 120 days (IQR:81-207), and the late period had a median half-life of 214 days (IQR:140-550).

CONCLUSION

These data establish antibody durability of ECV-19, using a framework to analyze COVID-19 vaccine-induced antibodies during periods of high infection.

Hand hygiene knowledge, attitude, barriers and improvement measures among healthcare workers in the Republic of Korea: a cross-sectional survey exploring interprofessional differences

BACKGROUND

Hand hygiene (HH) is a fundamental component of infection prevention and control in healthcare settings. This study aimed to identify knowledge, attitude, and barriers to HH according to occupational groups and strategies to increase the rate of HH compliance among healthcare workers (HCWs).

METHODS

This cross-sectional survey was conducted in July 2018 at four university-affiliated hospitals. The survey comprised seven parts with 49 items, including self-reported HH compliance, knowledge, attitudes, behaviours, barriers to HH, and improvement strategies.

RESULTS

A total of 1046 HCWs participated in the survey. The nursing group's self-reported HH compliance rate was the highest, followed by other HCWs and physicians. The scores regarding knowledge, attitudes, and behaviours regarding HH were the highest in the nursing group. The nursing group also had higher internal and emotional motivation scores. Physicians and nurses found HH the most challenging in emergencies, while other HCWs considered skin problems caused by HH products the most significant barrier. Among 12 improvement measures, approximately 20% of the respondents ranked "diversify types of hand sanitisers," "install soap and paper towels in each hospital room," and "change perception through various HH campaigns" as the top three priorities. The physician group deemed the timely reminder of HH compliance as the second most critical improvement measure.

CONCLUSION

Differences in knowledge, attitude and barriers hindering HH compliance and improvement plans were identified for each group. The findings suggest that targeted interventions tailored to the specific needs of different occupational groups may effectively improve HH compliance in healthcare settings.

Effects of Omicron Infection and Changes in Serum Antibody Response to Wild-Type, Delta, and Omicron After a Booster Dose With BNT163b2 Vaccine in Korean Healthcare Workers

BACKGROUND

Although the primary vaccine coverage rate for coronavirus disease 2019 (COVID-19) in South Korea has exceeded 80%, the coronavirus continues to spread, with reports of a rapid decline in vaccine effectiveness. South Korea is administering booster shots despite concerns about the effectiveness of the existing vaccine.

METHODS

Neutralizing antibody inhibition scores were evaluated in two cohorts after the booster dose. For the first cohort, neutralizing activity against the wild-type, delta, and omicron variants after the booster dose was evaluated. For the second cohort, we assessed the difference in neutralizing activity between the omicron infected and uninfected groups after booster vaccination. We also compared the effectiveness and adverse events (AEs) between homologous and heterologous booster doses for BNT162b2 or ChAdOx1 vaccines.

RESULTS

A total of 105 healthcare workers (HCWs) that were additionally vaccinated with BNT162b2 at Soonchunhyang University Bucheon Hospital were enrolled in this study. Significantly higher surrogate virus neutralization test (sVNT) inhibition (%) was observed for the wild-type and delta variants compared to sVNT (%) for the omicron after the booster dose (97%, 98% vs. 75%; P < 0.001). No significant difference in the neutralizing antibody inhibition score was found between variants in the BNT/BNT/BNT group (n = 48) and the ChA/ChA/BNT group (n = 57). Total AEs were not significantly different between the ChA/ChA/BNT group (85.96%) and the BNT/BNT group (95.83%; P = 0.11). In the second cohort with 58 HCWs, markedly higher sVNT inhibition to omicron was observed in the omicron-infected group (95.13%) compared to the uninfected group (mean of 48.44%; P < 0.001) after four months of the booster dose. In 41 HCWs (39.0%) infected with the omicron variant, no difference in immunogenicity, AEs, or effectiveness between homogeneous and heterogeneous boosters was observed.

CONCLUSION

Booster vaccination with BNT162b2 was significantly less effective for the neutralizing antibody responses to omicron variant compared to the wild-type or delta variant in healthy population. Humoral immunogenicity was sustained significantly high after 4 months of booster vaccine in the infected population after booster vaccination. Further studies are needed to understand the characteristics of immunogenicity in these populations.

Rheumatoid factor is associated with severe COVID ‐19

AIM

Coronavirus disease 2019 (COVID-19) has been proposed as triggering autoimmunity. The aim of this study was to evaluate the presence and clinical significance of autoantibodies in patients with COVID-19.

METHODS

We retrospectively collected data from 245 patients who were hospitalized for COVID-19. All patients were tested for the presence of antinuclear antibody (ANA), rheumatoid factor (RF), anti-citrullinated peptide antibody (ACPA), and anti-cytoplasmic neutrophil antibody (ANCA). Risk factors for death and critical COVID-19, defined as the need for invasive mechanical ventilation or extracorporeal membrane oxygenation, were analyzed.

RESULTS

Ninety (36.7%) patients tested positive for ANA, and 51 (20.8%) patients tested positive for RF. Three patients each (1.2%) tested positive for ACPA and ANCA. RF-positive patients had higher rates of invasive mechanical ventilation and death than RF-negative patients (70.6% vs 28.4%, P < 0.001 and 45.1% vs 18.6%, P < 0.001, respectively). Underlying lung disease, kidney disease, heart disease, quick COVID severity index (qCSI), and lactate dehydrogenase (LDH) were associated with in-hospital death. RF (odds ratio [OR] 7.31, 95% CI 2.50-21.37, P < 0.001), qCSI (OR 1.42, 95% CI 1.19-1.69, P < 0.001), and LDH (OR 1.004, 95% CI 1.002-1.005, P < 0.001) were associated with critical COVID-19. Combination of RF, qCSI, and LDH showed good prognostic value (area under the curve = 0.903, P < 0.001) for critical COVID-19.

CONCLUSIONS

ANA and RF were frequently detected in COVID-19 patients. RF could be a risk factor for critical COVID-19. The results of this study suggest immune dysfunction contributes to the complications of COVID-19.

1973. The Antibody Neutralization Level after a BNT162b2 Vaccine Booster in Korean Healthcare Workers

Background

We compared neutralizing antibodies in healthy healthcare workers against two different coronavirus 2019 disease (Covid-19) vaccines, a messenger RNA (mRNA)-based vaccine (BNT162b2) and a genetically modified organism (virus vector) vaccine (ChAdOx1), to obtain immunity. In our cohort, we tried to compare the level of neutralizing antibody production after a BNT162b2 vaccine booster and to analyze the level of neutralizing antibody titers for delta and omicron variant.

Methods

On November 23 to 25, 2021 and December 23 to 24, 2021, a total of 2,133 HCWs at Soonchunhyang University Bucheon Hospital had been vaccinated with BNT162b2 (Pfizer-BioNTech). Among the 115 HCWs who participated in the preceding study, all participants had no history of Covid-19 infection or suspected symptoms at the time of registration. We collected blood samples from participants four weeks after a third dose. All blood samples were analyzed using the commercial virus neutralization test kit (Genscript Biotech Corporation, Piscataway, NJ, USA).

Results

Titers were measured 2 months after the initial vaccination and before the booster of the BNT162b2 vaccine (i.e. 6 months after the initial vaccination), and 4 weeks after the booster. Neutralizing antibody level measured by percentage inhibition of surrogate virus neutralization test (sVNT) readings at negative control (unvaccinated) and 4 weeks after booster vaccination. BNT/BNT/BNT group was defined as a booster dose with BNT162b2 (Pfizer) after two doses of BNT162b2 vaccine (Pfizer) 3 weeks apart. ChA/ChA/BNT group was defined as a booster dose with BNT162b2 (Pfizer) after two doses of ChAdOx1 vaccine (AstraZeneca/Oxford) 12 weeks apart.

Conclusion

We found that the neutralizing antibody levels against omicron variant were higher among those who received a booster dose of the BNT162b2 vaccine.

Disclosures

All Authors: No reported disclosures.

291. Retrospective Study on Bacteremia in COVID-19 Patients in the Delta and Omicron Era

Background

The coronavirus disease 2019 (COVID-19) outbreak reached peak levels in South Korea as the Delta variant, dominant from late August until the end of 2021, was rapidly overtaken by the Omicron variant at the start of 2022. In studies conducted near the start of the pandemic, the occurrence of bacteremia in COVID-19 patients was relatively low. We aimed to determine if there was a change in the rate of bacteremia in COVID-19 patients with the progression of the pandemic.

Methods

We performed a retrospective study of patients who were diagnosed with COVID-19 at a referral hospital between September 2021 and March 2022. Blood culture results were recorded, along with demographic characteristics and clinical outcomes. Contamination was considered when a single blood culture was positive for coagulase-negative staphylococci (CoNS), Corynebacterium species, or Bacillus species. Clinically relevant bacteremia was defined as bacteremia due to clinically significant pathogens between 7 days before COVID-19 diagnosis to 14 days after diagnosis.

Results

Among the 360 patients included in the study, 46 cases from 43 (11.9%) patients were considered to be clinically relevant bacteremia. Enterococcus faecalis (17.4%) and CoNS (17.4%) were the most common pathogens, followed by Acinetobacter baumannii (15.2%), Staphylococcus aureus (10.7%) and Escherichia coli (10.7%). The median number of days from COVID-19 diagnosis to identification of bacteremia was 2 days. There was no significant difference in the rate of bacteremia between the Delta (September-December 2021) and Omicron variant eras (January-March 2022) (12.2% vs. 11.7%, P = .88). In the subgroup analysis of patients who received more than 2 days of intensive care, there was no statistical difference in the rate of bacteremia (14.5% [9/62] in the Delta variant era vs. 16.9% [14/83] in the Omicron variant era; P = .70). Mortality was significantly higher in patients with clinically relevant bacteremia (48.8% vs. 19.2%, P < .001).

Conclusion

Many COVID-19 patients had bacteremia in the Omicron variant era, especially in the intensive care unit. Clinicians should suspect bacterial co-infection when a COVID-19 patient is clinically aggravated.

Disclosures

All Authors: No reported disclosures.

Interim analysis from a phase 2 randomized trial of EuCorVac-19: a recombinant protein SARS-CoV-2 RBD nanoliposome vaccine

BACKGROUND

Numerous vaccine strategies are being advanced to control SARS-CoV-2, the cause of the COVID-19 pandemic. EuCorVac-19 (ECV19) is a recombinant protein nanoparticle vaccine that displays the SARS-CoV-2 receptor-binding domain (RBD) on immunogenic nanoliposomes.

METHODS

Initial study of a phase 2 randomized, observer-blind, placebo-controlled trial to assess the immunogenicity, safety, and tolerance of ECV19 was carried out between July and October 2021. Two hundred twenty-nine participants were enrolled at 5 hospital sites in South Korea. Healthy adults aged 19-75 without prior known exposure to COVID-19 were vaccinated intramuscularly on day 0 and day 21. Of the participants who received two vaccine doses according to protocol, 100 received high-dose ECV19 (20 μg RBD), 96 received low-dose ECV19 (10 μg RBD), and 27 received placebo. Local and systemic adverse events were monitored. Serum was assessed on days 0, 21, and 42 for immunogenicity analysis by ELISA and neutralizing antibody response by focus reduction neutralization test (FRNT).

RESULTS

Low-grade injection site tenderness and pain were observed in most participants. Solicited systemic adverse events were less frequent, and mostly involved low-grade fatigue/malaise, myalgia, and headache. No clinical laboratory abnormalities were observed. Adverse events did not increase with the second injection and no serious adverse events were solicited by ECV19. On day 42, Spike IgG geometric mean ELISA titers were 0.8, 211, and 590 Spike binding antibody units (BAU/mL) for placebo, low-dose and high-dose ECV19, respectively (p < 0.001 between groups). Neutralizing antibodies levels of the low-dose and high-dose ECV19 groups had FRNT₅₀ geometric mean values of 129 and 316, respectively. Boosting responses and dose responses were observed. Antibodies against the RBD correlated with antibodies against the Spike and with virus neutralization.

CONCLUSIONS

ECV19 was generally well-tolerated and induced antibodies in a dose-dependent manner that neutralized SARS-CoV-2. The unique liposome display approach of ECV19, which lacks any immunogenic protein components besides the antigen itself, coupled with the lack of increased adverse events during boosting suggest the vaccine platform may be amenable to multiple boosting regimes in the future. Taken together, these findings motivate further investigation of ECV19 in larger scale clinical testing that is underway.

TRIAL REGISTRATION

The trial was registered at ClinicalTrials.gov as # NCT04783311.

A Transient Effect of Convalescent Plasma Therapy in a Patient with Severe Covonavirus Disease 2019: A Case Report

A 65-year-old male patient with an end-stage renal disease was diagnosed with coronavirus disease 2019 (COVID-19) by reverse transcription polymerase chain reaction. The patient complained of cough, sputum, and respiratory distress that worsened three days ago. The patient required mechanical ventilation and extracorporeal mentrane oxygenation. On day 9, convalescent plasma collected from a 34-year old man who recovered from COVID-19 45 days ago was administered. The patient showed immediate clinical improvement. However, on day 14, the patient’s clinical course worsened again. On day 19 and day 24, vancomycin-resistant Enterococcus faecium bacteremia and methicillin-resistant Staphylococcus aureus pneumonia were found. After long-term supportive care, he slowly recovered. He was discharged on day 91 without any oxygen requirement. This case report suggests that convalescent plasma therapy might just provide a short-term relief and that persistent effort for critical care is necessary to save patients from severe COVID-19.

Risk factors for isolation of multi-drug resistant organisms in coronavirus disease 2019 pneumonia: A multicenter study

Objectives

Superimposed multi-drug resistant organisms (MDROs) co-infection can be associated with worse outcomes in patients with severe coronavirus disease 2019 (COVID-19), even if these patients were managed with strict airborne and contact precautions. Identifying risk factors for isolation of MDROs is critical to COVID-19 treatment.

Methods

All eligible adult patients with confirmed COVID-19 pneumonia from 10 hospitals in the Republic of Korea between February 2020 and May 2020 were retrospectively enrolled. Using this cohort, epidemiology and risk factors for isolation of MDROs were evaluated.

Results

Of 152 patients, 47 with microbial culture results were included. Twenty isolates of MDROs from 13 (28%) patients were cultured. Stenotrophomonas maltophilia (5 isolates) was the most common MDRO, followed by methicillin-resistant staphylococcus aureus (4 isolates). MDROs were mostly isolated from sputum samples (80%, 16/20). The median time from hospitalization to MDRO isolation was 28 days (interquartile range, 18-38 days). In-hospital mortality was higher in patients with MDRO isolation (62% vs 15%; P = .001). Use of systemic corticosteroids after diagnosis of COVID-19 (adjusted odds ratio [aOR]: 15.07; 95% confidence interval [CI]: 2.34-97.01; P = .004) and long-term care facility (LTCF) stay before diagnosis of COVID-19 (aOR: 6.09; 95% CI: 1.02-36.49; P = .048) were associated with MDRO isolation.

Conclusions

MDROs were isolated from 28% of COVID-19 pneumonia patients with culture data and 8.6% of the entire cohort. Previous LTCF stay and adjunctive corticosteroid use were risk factors for the isolation of MDROs. Strict infection prevention strategies may be needed in these COVID-19 patients with risk factors.

Dual respiratory virus detection in adult patients with acute respiratory illness

BACKGROUND

Nonrandom multiple respiratory virus (RV) detection provides evidence for viral interference among respiratory viruses. However, little is known as to whether it occurs randomly.

METHODS

The prevalence of dual RV detection (DRVD) in patients with acute respiratory illnesses (ARIs) at 4 academic medical centers was investigated; data about the prevalence of 8 RVs were collected from the Korean national RV surveillance dataset. Linear regression analysis was performed to assess the correlation between observed and estimated prevalence of each type of DRVD.

RESULTS

In total, 108 patients with ARIs showing DRVD were included in this study between 2011 and 2017. In several types of regression analysis, a strong correlation was observed between the observed and estimated prevalence of each type of DRVD. Excluding three DRVD types (influenza/picornavirus, influenza/human metapneumovirus, and adenovirus/respiratory syncytial virus), the slope of the regression line was higher than that of the line of random occurrence (1.231 > 1.000) and the 95% confidence interval of the regression line was located above the line of random occurrence.

CONCLUSIONS

Contrary to the results of previous epidemiologic studies, most types of DRVD occur more frequently than expected from the prevalence rates of individual RV, except for three underrepresented pairs above.

The Adjuvanted Recombinant Zoster Vaccine Confers Long-term Protection Against Herpes Zoster: Interim Results of an Extension Study of the Pivotal Phase III Clinical Trials (ZOE-50 and ZOE-70)

Background

This ongoing follow-up study evaluated the persistence of efficacy and immune responses for 6 additional years in adults vaccinated with the glycoprotein E (gE)-based adjuvanted recombinant zoster vaccine (RZV) at age ≥50 years in 2 pivotal efficacy trials (ZOE-50 and ZOE-70). The present interim analysis was performed after ≥2 additional years of follow-up (between 5.1 and 7.1 years [mean] post-vaccination) and includes partial data for year (Y) 8 post-vaccination.

Methods

Annual assessments were performed for efficacy against herpes zoster (HZ) from Y6 post-vaccination and for anti-gE antibody concentrations and gE-specific CD4[2+] T-cell (expressing ≥2 of 4 assessed activation markers) frequencies from Y5 post-vaccination.

Results

Of 7413 participants enrolled for the long-term efficacy assessment, 7277 (mean age at vaccination, 67.2 years), 813, and 108 were included in the cohorts evaluating efficacy, humoral immune responses, and cell-mediated immune responses, respectively. Efficacy of RZV against HZ through this interim analysis was 84.0% (95% confidence interval [CI], 75.9–89.8) from the start of this follow-up study and 90.9% (95% CI, 88.2–93.2) from vaccination in ZOE-50/70. Annual vaccine efficacy estimates were >84% for each year since vaccination and remained stable through this interim analysis. Anti-gE antibody geometric mean concentrations and median frequencies of gE-specific CD4[2+] T cells reached a plateau at approximately 6-fold above pre-vaccination levels.

Conclusions

Efficacy against HZ and immune responses to RZV remained high, suggesting that the clinical benefit of RZV in older adults is sustained for at least 7 years post-vaccination.

Clinical Trials Registration. NCT02723773.

Impacts of Side Effects to BNT162b2 and the First Dose of ChAdOx1 Anti-SARS-CoV-2 Vaccination on Work Productivity, the Need for Medical Attention, and Vaccine Acceptance: A Multicenter Survey on Healthcare Workers in Referral Teaching Hospitals in the Republic of Korea

To establish a successful anti-SARS-CoV-2 vaccination strategy, it is necessary to take possible tradeoffs into account. We conducted a survey on vaccinated healthcare workers (HCWs) inthree referral teaching hospitals in the Republic of Korea. We investigated the frequency of vaccination side effects (SEs), the impact on their work productivity, the need for medical attention, and vaccine acceptance. Three groups of HCWs were surveyed: 1406 who had received the first dose of BNT162b2 (BNT162b2#1), 1168 who had received the second dose of BNT162b2 (BNT162b2#2), and 1679 who had received the first dose of ChAdOx1 (ChAdOx1#1). More SEs and impact on work productivity were reported in ChAdOx1#1 than in the other two groups. However, among individuals aged ≥40 years, no significant difference of absence from work was found between ChAdOx1#1 and BN162b2#2 (4.4%, 31/699 vs. 3.0%, 12/405; p = 0.26), and none were hospitalized. Older HCWs in ChAdOx1#1 showed intention to receive the second dose of the vaccine. Although the incidence of SEs and their impacts were greater after the first dose of ChAdOx1 than BNT162b2 in young people, significant impact of SEs seemed to be rare in individuals aged ≥40 years, regardless of the vaccine they received.

Promotion of healthcare personnel vaccinations among newly employed doctors and nurses: Evidence-guided strategy

OBJECTIVE

Healthcare personnel vaccinations are important to prevent vaccine-preventable diseases in hospitals. We evaluated the seroprevalence, vaccination rates, and barriers to vaccination among newly employed nurses and doctors.

METHODS

A cross-sectional study was conducted at a university hospital in the Republic of Korea from 2017 to 2020. The immune status for hepatitis B virus (HBV), varicella zoster virus (VZV), and hepatitis A virus (HAV) was tested. HBV, VZV, measles, mumps, and rubella (MMR) vaccinations were mandatory. HAV and tetanus-diphtheria-pertussis (Tdap) vaccinations were also recommended by specialists. A web-based survey on factors affecting vaccination completion was conducted.

RESULTS

For the 668 participants, the mean age was 26 ± 2 (±SD) years. Seroprevalence was 86% for HBV, 93% for VZV, and 59% for HAV. Vaccine completion rates were 40% for HBV, 70% for VZV, 65% for MMR, 42% for HAV, and 70% for Tdap. Overall compliance for mandatory vaccines was 54%. A total of 402 subjects who had worked for over one year were surveyed, with a 22% response rate. More than 50% of respondents gave the following reasons for not receiving recommend vaccines: 1) they were busy (77%), 2) vaccination process was complicated (68%), and 3) they simply forgot about vaccination (55%). Healthcare personnel agreed to be frequently informed of immunization requirements and for monitoring of vaccination rates.

CONCLUSION

Vaccination compliance among newly employed doctors and nurses was 54%. Active interventions such as simplifying the vaccination process and frequent notifications are needed to achieve optimal immunization rates.

Safety and immunogenicity of a seasonal quadrivalent influenza vaccine (GC3110A) in healthy participants aged ≥ 65 years

BACKGROUND

Seasonal Influenza is still considered associated with seasonal morbidity and hospitalization in the elderly population. The World Health Organization (WHO) recommended seasonal quadrivalent influenza vaccine (QIV) to reduce burden of two currently circulating influenza B lineages. Until 2019 Korean National Immunization Program (NIP) recommended trivalent influenza vaccine (TIV) after ongoing debates on cost effectiveness of QIV for elderly population. Although influenza vaccine only showed modest effect on reducing influenza in elderly, this study aimed to evaluate the immunogenicity and safety of inactivated QIV in healthy participants ≥ 65 years of age.

METHODS

A total of 274 healthy participants aged ≥ 65 years received a QIV. Seroconversion-based vaccine efficacy of 4 strains of seasonal influenza was assessed 21 days after vaccination and adverse events were monitored until 180 days after vaccination.

RESULTS

The percentages of participants seroconverted after vaccination on HI antibody against each strain were 36.5% (99/271) to A/H1N1, 47.6% (129/271) to A/H3N2, 40.6% (110/271) to B Yamagata, and 49.1% (133/271) to B Victoria. The percentages of participants seroprotected after vaccination on HI antibody against each strain were 81.2% (220/271) to A/H1N1, 98.5% (267/271) to A/H3N2, 95.2% (258/271) to B Yamagata, and 93.7% (254/271) to B Victoria. There was no serious adverse event (SAE) related with the study vaccine.

CONCLUSION

The quadrivalent split influenza vaccine is expected to offer seroprotection against influenza A and both influenza B lineages even in the elderly population.

Predictors of Acute Kidney Injury and 28-Day Mortality in Carbapenem-Resistant Acinetobacter baumannii Complex Bacteremia

Colistin is an, antibiotic used to treat carbapenem-resistant Acinetobacter baumannii complex (CRABC) infection. However, colistin is well known for its nephrotoxicity. To accurately assess the effects of colistin on acute kidney injury (AKI) and 28-day mortality, we investigated the risk factors associated with AKI and mortality in patients with CRABC bacteremia who received or never received colistin. Patients with CRABC bacteremia aged ≥18 years were retrospectively identified for 3 years at five tertiary teaching hospitals. AKI was defined by using the Kidney Disease Improving Global Outcomes criteria. AKI developed in 103 (34.9%) of the 295 patients enrolled patients. AKI developed more frequently in patients who received colistin than in patients who did not (46.7% vs. 29.5%, p = 0.004). Multivariate analysis showed that intravenous colistin usage was an independent risk factor for AKI in these patients. Nonfatal disease, catheter-related bloodstream infection, and administration of colistin were protective factors for 28-day mortality. However, the sequential organ failure assessment score and AKI were associated with poor outcomes. In conclusion, colistin may be a double-edged sword; although it causes AKI, it also reduces 28-day mortality in patients with CRABC bacteremia. Therefore, colistin administration as an appropriate antibiotic may improve CRABC bacteremia prognosis, despite its nephrotoxicity.

The adjuvanted recombinant zoster vaccine is efficacious and safe in Asian adults ≥ 50 years of age: a sub-cohort analysis of the ZOE-50 and ZOE-70 randomized trials

In two large clinical trials (ZOE-50 [NCT01165177] and ZOE-70 [NCT01165229]), two doses of the adjuvanted recombinant zoster vaccine (RZV) demonstrated >90% efficacy (VE) against herpes zoster (HZ) in adults ≥50 years of age (YOA). This post-hoc analysis assessed the VE against HZ and postherpetic neuralgia (PHN), in participants from Asian study sites enrolled in ZOE-50/70. Reactogenicity and safety were also assessed. Participants ≥50 YOA were randomized 1:1 to receive 2 doses of either RZV or placebo, 2 months apart. VE was evaluated for a median follow-up of 4 years post-vaccination overall and by age in the ZOE-50 Asian population ≥50 YOA and in the pooled ZOE-50/70 Asian population ≥70 YOA. Of the 2,729 participants included in the ZOE-50 Asian population ≥50 YOA, 3 RZV and 66 placebo recipients reported a confirmed HZ episode. Overall VE was 95.6% (95% confidence interval [CI]: 86.4–99.1) against HZ and 100% (95% CI: 35.44–100) against PHN. In the pooled ZOE-50/70 Asian population ≥70 YOA, 4 RZV and 75 placebo recipients out of the 2,723 participants reported a confirmed HZ episode. Overall VE was 94.7% (95% CI: 85.9–98.6) against HZ and 89.8% (95% CI: 28.39–99.77) against PHN. Pain and myalgia were the most frequent solicited local and general adverse events, respectively, in both populations. No safety concern was identified during the study periods. RZV is highly efficacious against HZ and PHN and has an acceptable safety profile in Asian populations ≥50 YOA, similar to what was observed in the general ZOE-50/70 populations.

Trademark statement: Shingrix is a trademark owned by or licensed to the GSK group of companies.

1433. Promoting Vaccination of Vaccine Preventable Diseases in Newly Employed Nurses and Doctors Guided by Serological Study

Background

Vaccination after serological evaluation of healthcare workers is key component of vaccine preventable diseases (VPDs) preparedness in hospital. The aim of this study is to determine the seroprevalence of VPDs and the vaccination rates among newly employed nurses and doctors.

Methods

A cross-sectional study was conducted at a referral university hospital in the Republic of Korea. All newly employed nurses and doctors without immunity were recommended to have the hepatitis B virus (HBV), varicella zoster virus (VZV), measles, mumps, and rubella (MMR), hepatitis A virus (HAV) and tetanus-diphtheria-pertussis (Tdap) vaccination. HBV, VZV, MMR vaccinations were financially supported and Tdap vaccination was recommended without testing. We investigated the seroprevalence of HAV, HBV, and VZV and vaccination rate of recommended vaccination (HAV, HBV, MMR, VZV, and Tdap) from Jan 1^st, 2017 to March 31^th, 2020.

Results

A total of 668 (527 female, 141 male) newly employed nurses and doctors were identified. The median age (IQR) is 25 (24-27). Seroprevalence were 59.1% (95% confidence interval [CI] 55.4-62.8) for HAV, 86.1% (95% CI 83.5-88.7) for HBV, and 92.4% (95% CI 90.4-94.4) for VZV. Vaccination rate of recommended vaccination were 24.5% (95% CI 18.5-30.5) for HAV, 23.3% (95% CI 13.6-33.0) for HBV, 48.7% (95% CI 33.0-64.4) for VZV, 30.0% (95% CI 25.5-34.5) for MMR and 33.1% (95% CI 29.0-37.2) for Tdap respectively.

Conclusion

Seroprevalence of HAV was lower than HBV and varicella in newly employed nurses and doctors. Although persistent effort to improve the healthcare worker’s vaccination, the actual rates were low. Further strategy promoting vaccination of newly employed nurses and doctors are needed.

Disclosures

All Authors: No reported disclosures

Infectious Diseases Physician Workforce in Korea

This study aimed to evaluate the infectious disease (ID) physician workforce in Korea. We investigated the acquisition of ID physicians from 1992 to 2019 with their current working place in the Health Care System. We defined ID physicians working at general or tertiary-care hospitals as active ID physicians. A total 275 physicians acquired ID as a sub-specialty. Among the 275, 242 were active ID physicians. The density of active ID physicians was 0.47 per 100,000 population. Of all the 17 administrative districts, 11 (64.7%) fell short of 0.47, and 131 medical institutions employed the service of ID physicians. The median number of beds per adult ID physician was 372 (interquartile range, 280-507). It is essential to secure human resources to respond to emerging infectious diseases and perform the inherent work of ID physicians.

Machine-Learning-Based Approach to Differential Diagnosis in Tuberculous and Viral Meningitis

Background

Tuberculous meningitis (TBM) is the most severe form of tuberculosis, but differentiating between the diagnosis of TBM and viral meningitis (VM) is difficult. Thus, we have developed machine-learning modules for differentiating TBM from VM.

Material and Methods

For the training data, confirmed or probable TBM and confirmed VM cases were retrospectively collected from five teaching hospitals in Korea between January 2000 - July 2018. Various machine-learning algorithms were used for training. The machine-learning algorithms were tested by the leave-one-out cross-validation. Four residents and two infectious disease specialists were tested using the summarized medical information.

Results

The training study comprised data from 60 patients with confirmed or probable TBM and 143 patients with confirmed VM. Older age, longer symptom duration before the visit, lower serum sodium, lower cerebrospinal fluid (CSF) glucose, higher CSF protein, and CSF adenosine deaminase were found in the TBM patients. Among the various machine-learning algorithms, the area under the curve (AUC) of the receiver operating characteristics of artificial neural network (ANN) with ImperativeImputer for matrix completion (0.85; 95% confidence interval 0.79 - 0.89) was found to be the highest. The AUC of the ANN model was statistically higher than those of all the residents (range 0.67 - 0.72, P <0.001) and an infectious disease specialist (AUC 0.76; P = 0.03).

Conclusion

The machine-learning techniques may play a role in differentiating between TBM and VM. Specifically, the ANN model seems to have better diagnostic performance than the non-expert clinician.

Clinical Course and Molecular Viral Shedding Among Asymptomatic and Symptomatic Patients With SARS-CoV-2 Infection in a Community Treatment Center in the Republic of Korea

IMPORTANCE

There is limited information about the clinical course and viral load in asymptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

OBJECTIVE

To quantitatively describe SARS-CoV-2 molecular viral shedding in asymptomatic and symptomatic patients.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective evaluation was conducted for a cohort of 303 symptomatic and asymptomatic patients with SARS-CoV-2 infection between March 6 and March 26, 2020. Participants were isolated in a community treatment center in Cheonan, Republic of Korea.

MAIN OUTCOMES AND MEASURES

Epidemiologic, demographic, and laboratory data were collected and analyzed. Attending health care personnel carefully identified patients' symptoms during isolation. The decision to release an individual from isolation was based on the results of reverse transcription-polymerase chain reaction (RT-PCR) assay from upper respiratory tract specimens (nasopharynx and oropharynx swab) and lower respiratory tract specimens (sputum) for SARS-CoV-2. This testing was performed on days 8, 9, 15, and 16 of isolation. On days 10, 17, 18, and 19, RT-PCR assays from the upper or lower respiratory tract were performed at physician discretion. Cycle threshold (Ct) values in RT-PCR for SARS-CoV-2 detection were determined in both asymptomatic and symptomatic patients.

RESULTS

Of the 303 patients with SARS-CoV-2 infection, the median (interquartile range) age was 25 (22-36) years, and 201 (66.3%) were women. Only 12 (3.9%) patients had comorbidities (10 had hypertension, 1 had cancer, and 1 had asthma). Among the 303 patients with SARS-CoV-2 infection, 193 (63.7%) were symptomatic at the time of isolation. Of the 110 (36.3%) asymptomatic patients, 21 (19.1%) developed symptoms during isolation. The median (interquartile range) interval of time from detection of SARS-CoV-2 to symptom onset in presymptomatic patients was 15 (13-20) days. The proportions of participants with a negative conversion at day 14 and day 21 from diagnosis were 33.7% and 75.2%, respectively, in asymptomatic patients and 29.6% and 69.9%, respectively, in symptomatic patients (including presymptomatic patients). The median (SE) time from diagnosis to the first negative conversion was 17 (1.07) days for asymptomatic patients and 19.5 (0.63) days for symptomatic (including presymptomatic) patients (P = .07). The Ct values for the envelope (env) gene from lower respiratory tract specimens showed that viral loads in asymptomatic patients from diagnosis to discharge tended to decrease more slowly in the time interaction trend than those in symptomatic (including presymptomatic) patients (β = -0.065 [SE, 0.023]; P = .005).

CONCLUSIONS AND RELEVANCE

In this cohort study of symptomatic and asymptomatic patients with SARS-CoV-2 infection who were isolated in a community treatment center in Cheonan, Republic of Korea, the Ct values in asymptomatic patients were similar to those in symptomatic patients. Isolation of asymptomatic patients may be necessary to control the spread of SARS-CoV-2.

Management and outcomes of Burkholderia cepacia complex bacteremia in patients without cystic fibrosis: a retrospective observational study

Burkholderia cepacia complex (BCC) is an emerging pathogen of nosocomial infection in chronic or critically ill patients without cystic fibrosis (CF). The objective was to evaluate the management and outcomes of BCC bacteremia in patients without CF. We conducted a retrospective study of non-CF adult patients with BCC bacteremia between January 1997 and December 2016 at 4 tertiary hospitals in South Korea. A total of 216 non-CF patients with BCC bacteremia were identified. Most cases were hospital-acquired (79.2%), and the most common source was a central venous catheter (CVC) (42.1%). The rates of susceptibility to trimethoprim-sulfamethoxazole and piperacillin-tazobactam of BCC isolates were high as 92.8% and 90.3%, respectively. The rates of susceptibility to ceftazidime, meropenem, and levofloxacin were 75.5%, 72.3%, and 64.1%, respectively. The 14-day, 30-day, and in-hospital mortality rate was 19.4%, 23.1%, and 31.0%, respectively. Female (OR = 3.1; 95% CI, 1.4-6.8), liver cirrhosis (OR = 6.2; 95% CI, 1.6-16.6), septic shock (OR = 11.2; 95% CI, 5.1-24.8), and catheter-related infection (OR = 2.6, 95% CI, 1.2-5.8) were the independent risk factors for 30-day mortality. The outcome did not differ according to type of antibiotics used. Among 91 patients with CVC-related BCC bacteremia, delayed CVC removal (> 3 days) had a higher rate of persistent bacteremia (54.5 vs. 26.1%; P = 0.03) and lower rate of clinical response (49.0 vs. 71.9%; P = 0.04), compared with early CVC removal (within 3 days). BCC bacteremia occurring in non-CF patients was mostly hospital-acquired and CVC-related. Early removal of the catheter is crucial in treatment of CVC-related BCC bacteremia.

1209. Seroprevalence of Measles, Mumps, and Rubella in Korean Healthcare Workers and Strategy for Vaccination

Background

The measles, mumps, and rubella (MMR) vaccination to children was accelerated in South Korea as the National Immunization Programs in 1985. A two-dose MMR vaccination schedule was introduced in 1997. However, outbreaks of measles in healthcare institution continued to occur. Recent studies revealed that the seroprevalence of measles in healthcare workers (HCWs) was approximately 40–60% in twentieth. The purpose of this study was to determine the seroprevalence of MMR antibodies in HCWs to establish strategy for vaccination.

Methods

To prevent nosocomial transmission of measles, test for MMR antibody of HCWs was conducted in three teaching hospitals from January to February in 2019. The testing was conducted only in the patient contact departments. We excluded HCWs who did a history of vaccination after starting their work. Anti-measles IgG and anti-mumps IgG was detected using chemiluminescence immunoassay. Anti-rubella IgG was detected using chemiluninescence microparticle immunoassay. Equivocal value was treated as negative. We also compare the costs between strategies two-dose vaccination without antibody tests and vaccination after antibody testing.

Results

Total 598 HCWs were included in analysis. Of the HCWs tests, 92.6% were seropositive to measles, 86.6% to mumps, and 79.7% to rubella. In the linear regression analysis, the seropositive of measles and rubella antibodies was increased in proportion to age (β-coefficient 43.4, 95% CI 35.1–51.6, P < 0.001 and β-coefficient 10.2, 95% CI 7.2–13.2, respectively). But, the seropositive to mumps was not related to age (β-coefficient 2.6, 95% CI -5.4–10.7, P = 0.52). The HCWs who has seropositive to all MMR was 67.2%. It was highest in 1970th birthyear (77.1%) and lowest in 1980th birthyear (60.6%). It costs less 18,000 wons ($15.5) per HCWs in strategy of vaccination after antibody testing than two-dose vaccination without antibody testing.

Conclusion

Our data warrant the needs for routine antibody test for MMR, followed by MMR vaccination in Korean HCWS. We expect that this strategy can save costs and avoid unnecessary vaccination.

Disclosures

All authors: No reported disclosures.

1194. Gender Differences in Psychosocial Determinants of Hand Hygiene Among Doctors

Background

Hand hygiene (HH) is essential in the prevention of hospital-acquired infections. It is known that there are differences in the compliance of HH between men and women but the reason for this phenomenon is unclear.

Methods

A survey on HH was conducted in July 2018 among healthcare workers at four different referral hospitals in South Korea. The differences between male and female doctors were then analyzed. The survey included a structured questionnaire with seven parts: (1) self-assessment of HH execution rate, knowledge, attitude, and behavior regarding HH, (2) internal motivation for better HH, (3) obstacles for HH, (4) emotional motivation, (5) the need for external supervision, (6) preference for alcohol gel, and (7) embarrassment due to supervision.

Results

Of the 1046 healthcare workers that replied to the survey, 201 (19.2%) were doctors, and of these, 129 (63.5%) were men. There was no significant difference between male and female doctors on the questionnaire related to knowledge, attitude, and behavior regarding HH. On the questions regarding internal motivation for better HH, male doctors had a higher tendency to agree that “I would be better at HH if it was related to getting a promotion,” but the results were statistically insignificant (5.08 vs. 4.69, P = 0.08). For the 14 questions about the obstacles for HH, the following five categories showed significantly higher results in men: (1) HH is difficult in emergency situations (4.87 vs. 4.51, P = 0.02), (2) time that could be spent on something more important is wasted on HH (3.12 vs. 2.67, P = 0.008), (3) HH is not a habit (3.26 vs. 2.58, P = 0.002), (4) I often forget about HH situations (3.60 vs. 2.89, P = 0.002), and (5) I do not perform HH because there is no disadvantage when I do not perform it (3.06 vs. 2.42, P = 0.008). In the category “HH causes pain and dryness of hands,” female doctors had a significantly higher tendency to agree (3.62 vs. 4.32, P = 0.003). Among the questions regarding emotional motivation, women had a higher tendency to agree that “Seeing a fellow employee perform bad HH angers me,” but there was no statistical significance (3.73 vs. 4.10, P = 0.07).

Conclusion

There was a significant difference between male and female doctors regarding obstacles for HH. A campaign for HH based on these results could be helpful for increasing HH compliance.

Disclosures

All authors: No reported disclosures.

Early Intravenous Colistin Therapy as a Favorable Prognostic Factor for 28-day Mortality in Patients with CRAB Bacteremia: a Multicenter Propensity Score-Matching Analysis

BACKGROUND

Carbapenem-resistant Acinetobacter baumannii (CRAB) infection is associated with high mortality. One of the strategies to reduce the mortality in patients with CRAB infections is to use intravenous colistin early but the effect of this strategy has not been proven. Therefore, we investigated the association of early colistin therapy with 28-day mortality in patients with CRAB bacteremia.

METHODS

This retrospective multicenter propensity score-matching analysis was conducted in the Korea by reviewing the medical records of adult patients with CRAB bacteremia between January 2012 and March 2015. Early colistin therapy was defined as intravenous colistin administration for > 48 hours within five days after the blood culture collection. To identify the risk factors associated with the 28-day mortality in CRAB bacteremia, the clinical variables of the surviving patients were compared to those of the deceased patients.

RESULTS

Of 303 enrolled patients, seventy-six (25.1%) patients received early colistin therapy. The 28-day mortality was 61.4% (186/303). Fatal or rapidly-fatal McCabe classifications, intensive care unit admission, Sequential Organ Failure Assessment scores ≥ 8, vasopressor use, and acute kidney injury were statistically independent poor prognostic factors. Catheter-related infection and early colistin therapy (adjusted odds ratio [aOR], 0.45; 95% confidence interval [CI], 0.21-0.94) were independent favorable prognostic factors associated with 28-day mortality in patients with CRAB bacteremia. Early colistin therapy was still significantly associated with lower 28-day mortality in the propensity score-matching analysis (aOR, 0.31; 95% CI, 0.11-0.88).

CONCLUSION

This study suggests that early colistin therapy might help reduce the mortality of patients with CRAB bacteremia.

Monomicrobial gram-negative necrotizing fasciitis: An uncommon but fatal syndrome

This study aimed to characterize patients with monomicrobial gram-negative necrotizing fasciitis in three university hospitals in Korea. In this study, of the 115 patients with community-acquired necrotizing fasciitis, 67 (58%) had monomicrobial infections: 31 (27%) in the gram-negative group and 36 (31%) in the gram-positive group. The majority of patients in the gram-negative group were infected with Escherichia coli followed by Klebsiella pneumoniae and Vibrio vulnificus. More patients in the gram-negative group showed liver cirrhosis than those in the gram-positive group (39% vs. 14%, P = 0.02). In a multivariable logistic regression analysis, liver cirrhosis (adjusted odds ratio [aOR], 13.7; 95% confidence interval [CI], 2.9-67.0), treatment with antibiotics without surgery (aOR, 10.2; 95% CI, 2.1-48.3), and lower level of albumin (aOR 4.9; 95% CI, 1.6-14.9) were associated with 30-day mortality. Our findings suggest that gram-negative necrotizing fasciitis is more often associated with liver cirrhosis and has poorer outcomes than gram-positive necrotizing fasciitis.

Antibiotic Treatment of Vertebral Osteomyelitis caused by Methicillin-Susceptible Staphylococcus aureus: A Focus on the Use of Oral β-lactams

BACKGROUND

Vertebral osteomyelitis (VO) is a rare but serious condition, and a potentially significant cause of morbidity. Methicillin-susceptible Staphylococcus aureus (MSSA) is the most common microorganism in native VO. Long-term administration of parenteral and oral antibiotics with good bioavailability and bone penetration is required for therapy. Use of oral β-lactams against staphylococcal bone and joint infections in adults is not generally recommended, but some experts recommend oral switching with β-lactams. This study aimed to describe the current status of antibiotic therapy and treatment outcomes of oral switching with β-lactams in patients with MSSA VO, and to assess risk factors for treatment failure.

MATERIALS AND METHODS

This retrospective study included adult patients with MSSA VO treated at nine university hospitals in Korea between 2005 and 2014. Treatment failure was defined as infection-related death, microbiological relapse, neurologic deficits, or unplanned surgical procedures. Clinical characteristics and antibiotic therapy in the treatment success and treatment failure groups were compared. Risk factors for treatment failure were identified using the Cox proportional hazards model.

RESULTS

A total of 100 patients with MSSA VO were included. All patients were treated, initially or during antibiotic therapy, with one or more parenteral antibiotics. Sixty-nine patients received one or more oral antibiotics. Antibiotic regimens were diverse and durations of parenteral and oral therapy differed, depending on the patient and the hospital. Forty-two patients were treated with parenteral and/or oral β-lactams for a total duration of more than 2 weeks. Compared with patients receiving parenteral β-lactams only, no significant difference in success rates was observed in patients who received oral β-lactams for a relatively long period. Sixteen patients had treatment failure. Old age (adjusted hazard ratio [HR] 5.600, 95% confidence interval [CI] 1.402 - 22.372, P = 0.015) and failure to improve C-reactive protein levels at follow-up (adjusted HR 3.388, 95% CI 1.168 - 9.829, P = 0.025) were independent risk factors for treatment failure.

CONCLUSION

In the study hospitals, diverse combinations of antibiotics and differing durations of parenteral and oral therapy were used. Based on the findings of this study, we think that switching to oral β-lactams may be safe in certain adult patients with MSSA VO. Since limited data are available on the efficacy of oral antibiotics for treatment of staphylococcal VO in adults, further evaluation of the role of oral switch therapy with β-lactams is needed.

2371. Monomicrobial Gram-Negative Necrotizing Fasciitis: An Uncommon but Fatal Syndrome

Background

Necrotizing fasciitis is a rapid progressive and potentially life-threatening infection. Although the relative emergence of non-synergistic single Gram-negative organisms as pathogen could be a therapeutic issue for clinicians, limited studies so far described the characteristics due to the low incidence.

Methods

We retrospectively reviewed clinical data of necrotizing fasciitis patients who were clinically diagnosed between May 2001 and December 2015 in university hospitals of three different cities of the Republic of Korea. We compared clinical characteristics and outcomes of patients with monomicrobial Gram-negative with those of the Gram-positive counterpart.

Results

A total of 115 patients with community acquired necrotizing fasciitis were identified. Among them, monomicrobial infections were 67 (58%) cases: 31 (27%) in the Gram-negative group and 36 (31%) in the Gram-positive group. The majority of Gram-negative group was E. coli followed by K. pneumonia and V. vulnificus. There were more cases of the Gram-negative group showing liver cirrhosis (39% vs. 14%, P = 0.02) and bacteremia (52% vs. 16%, P = 0.02). A total of 23 (10%) patients died within 30 days, including 15 (19%) in the Gram-negative group and 8 (10%) in the Gram-positive group (P = 0.02). In multivariable logistic regression, liver cirrhosis (adjusted odds ratio [aOR], 13.7; 95% confidence interval [CI], 2.9–67.0), treatment with antibiotics without surgery (aOR, 10.2; 95% CI, 2.1–48.3), and lower level of albumin (aOR 4.9; 95% CI, 1.6–14.9) were significantly associated with 30-day mortality.

Conclusion

Our findings suggest that necrotizing fasciitis caused by Gram-negative pathogen more often associated with liver cirrhosis and has poorer outcomes than the Gram-positive counterpart.

Disclosures

All authors: No reported disclosures.

1157. Optimal Isolation Periods Based on Time Interval to Elimination of Scabies After Topical Agent in the Real Clinical Practice

Background

Scabies reemerged globally as the ninth of most highly prevalent skin diseases from 1990 to 2010. Existing topical agents, like permethrine and lindane are highly effective showing 95% or more therapeutic response. Patient isolation is only recommended for one day after treating with topical agents. However, there is little evidence-based recommendation on optimal isolation period after treatment in healthcare settings to prevent secondary infection.

Methods

All patients who were diagnosed from 2008 to 2017 with scabies at a referral university hospital in Seoul, Republic of Korea were analyzed. We investigated the time interval between symptom onset and diagnosis of scabies. The period from the application of topical agents and clinical resolution was also analyzed.

Results

A total of 23 patients were diagnosed with scabies. There was no crusted scabies such as Norwegian scabies. Seventy percent of these patients were referred from long-term care facilities. Median number of treatment was three times per patient (Interquartile range [IQR], 2–3). Time interval between the onset of symptoms and the diagnosis of scabies was median 4 days (IQR, 2–14). Median isolation period was 13 days (IQR, 8–15). Dermatologist confirmed successful treatment of 16 patients, the median time until confirmation was 15 days (IQR, 8–17). Three patients discontinued isolation before dermatologist’s confirmation. After re-evaluation by a dermatologist, one of the three was re-isolated due to persistent scabies infestation.

Conclusion

Scabicides are highly efficacious, but repeated microscopic examination for confirming elimination is strongly recommended. Optimal isolation period should be individualized based on the repeated dermatologic examination.

Disclosures

All authors: No reported disclosures.

754. Prevalence of Latent Tuberculosis Infection Among Healthcare Workers at a Tertiary Care University Hospital

Background

We investigated the prevalence of latent tuberculosis infection (LTBI) among healthcare workers (HCWs) and analyzed its risk factors in a tertiary care university hospital in South Korea in a population with intermediate tuberculosis (TB) burden.

Methods

A standard questionnaire regarding the baseline demographics and risk factors for LTBI was given to each participant. QuantiFERON-TB GOLD In-Tube (QFT-GIT) assay and chest radiography were performed to investigate the rate of LTBI.

Results

A total of 1,429 participants, 213 (14.9%) doctors and 988 (69.1%) nurses and 228 (16.0%) others were enrolled. The mean age of the subjects was 33.0 years old, and 1,175 (82.2%) were female. Of the participants, 94.5% had received BCG vaccine. QFT-GIT assays were positive for 156 subjects (10.9%). Of the 213 doctors, 28 (13.1%) were positive by QFT-GIT, and among the 988 nurses, 94 (9.5%) had positive QFT-GIT results. Experience of working in hospital was significantly associated with positive LTBI test results by QFT-GIT assay. Gender and duration of employment as an HCW were significantly associated with having a positive QFT-GIT result in univariate analyses. In multivariate analyses, duration of employment as an HCW (>15 years) (odds ratio, 1.98; 95% confidence interval, 1.14–3.43) was independently associated with increased risk of a positive QFT-GIT result.

Conclusion

A high prevalence of LTBI was found among our HCWs. Considering the association between the experience of working in hospital and high risk of LTBI. The risk for tuberculosis infection among HCWs was higher than general population, which suggests that stricter preventive strategies against nosocomial tuberculosis infection should be implemented.

Disclosures

All authors: No reported disclosures.

Clinical and Molecular Characterization of Panton-Valentine Leukocidin-Positive Invasive Staphylococcus aureus Infections in Korea

AIM

Panton-Valentine leukocidin (PVL) is a virulent cytotoxin and an indicator of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection. In this study, we evaluated the prevalence and clinical and molecular characteristics of PVL-positive invasive S. aureus (ISA) infections in Korea.

RESULTS

A collection of 1,962 nonduplicate clinical isolates were screened for multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec), accessory gene regulator typing, major toxins, and antimicrobial susceptibility. Twenty-eight (1.4%) PVL-positive S. aureus samples were found; of them 19 (67.9%) were MRSA (8 CA and 11 healthcare-associated infections). Seventeen patients (60.7%) were men (median age: 63 years; range: 13-93 years) and 12 patients (42.9%) had no underlying comorbidities. The most common infections were skin and skin structure infection (SSSI) and pneumonia. The 30-day mortality rate was 37.0%. The most common PVL-positive MRSA clones were ST8-SCCmec IVa and ST30-SCCmec IVc along with their single-locus variants. Antimicrobial susceptibility and toxin-gene profile differed according to the clone.

CONCLUSIONS

ISA infections caused by PVL-positive strains are rare in Korea, with the two most common infections being SSSI and pneumonia. Our findings indicated that several PVL-positive MRSA clones, predominantly ST8-SCCmecIVa and ST30-SCCmecIVc, were circulating and causing sporadic cases of ISA infections in the community and hospital settings.

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.

Natural prognosis of carbapenem-resistant Acinetobacter baumannii bacteremia in patients who did not receive appropriate antibiotic treatment: A retrospective multicenter study in Korea

Carbapenem-resistant Acinetobacter baumannii (CRAB) infection is a major issues in current era. The aim of study was to investigate the natural prognosis and prognostic factors associated with 28-day mortality in patients with CRAB bacteremia who were not receiving appropriate antibiotic treatment.Adult patients with CRAB bacteremia were retrospectively identified between April 2012 and March 2015 at 5 tertiary hospitals in Republic of Korea. Patients who were transferred to another hospital within 28 days of onset of bacteremia and who receive appropriate antibiotics more than 48 hours were excluded. We investigated prognostic factors associated with 28-day mortality in patients with CRAB bacteremia without appropriate antibiotic treatment.Of enrolled 205 patients, 143 (69.8%) patients died within 28 days after blood culture. Of patients with 28-day mortality, 88.9% (127/143) of patients died within 5 days. Of 78 patients who survived more than 5 days, the 28-day mortality was 20.5% (16/78). Diabetes mellitus (adjusted odds ratio [aOR] 3.81, 95% confidence interval [95% CI] 1.19-12.20), immunocompromised (aOR 8.72, 95% CI 2.62-29.70), sequential organ failure assessment (SOFA) ≥ 10 (aOR 13.87, 95% CI 3.70-51.96), vasopressor use (aOR 7.03, 95% CI 1.79-27.60), and pneumonia (aOR 4.44, 95% CI 1.67-11.78) were found to be the factors independently associated with the 28-day mortality.The 28-day mortality in patients with CRAB bacteremia without appropriate treatment was high, although some patients could survive. Severity and underlying conditions were important prognostic factors in patients with CRAB bacteremia.

Hospital-based Influenza Morbidity and Mortality (HIMM) Surveillance for A/H7N9 Influenza Virus Infection in Returning Travelers

Since 2013, the Hospital-based Influenza Morbidity and Mortality (HIMM) surveillance system began a H7N9 influenza surveillance scheme for returning travelers in addition to pre-existing emergency room (ER)-based influenza-like illness (ILI) surveillance and severe acute respiratory infection (SARI) surveillance. Although limited to eastern China, avian A/H7N9 influenza virus is considered to have the highest pandemic potential among currently circulating influenza viruses. During the study period between October 1st, 2013 and April 30th, 2016, 11 cases presented with ILI within seven days of travel return. These patients visited China, Hong Kong, or neighboring Southeast Asian countries, but none of them visited a livestock market. Seasonal influenza virus (54.5%, 6 among 11) was the most common cause of ILI among returning travelers, and avian A/H7N9 influenza virus was not detected during the study period.

Outcome in Patients with Fever of Unknown Origin whose ¹⁸Fluoro-Deoxyglucose Positron Emission Tomography/Computerized Tomography Finding is Non-Diagnostic

Prognosis has not been known for patients with fever of unknown origin (FUO) whose ¹⁸fluoro-deoxyglucose (¹⁸F-FDG) positron emission tomography/computerized tomography (PET/CT) finding is non-diagnostic. A total of eight patients with FUO that underwent ¹⁸F-FDG PET/CT were retrospectively identified January 2016 - June 2017 in a tertiary hospital in Korea. Of these, two patients were diagnosed with microscopic polyangitis and Kikuchi’s disease and one patient was transferred to another hospital. Of five patients whose diagnoses were not confirmed, four patients received non-steroidal anti-inflammatory drug and/or low dose steroid and symptoms disappeared. Our study suggests that outcome of patients with FUO whose ¹⁸F-FDG PET/CT finding is non-diagnostic would be favorable.

Low Lymphocyte Proportion in Bronchoalveolar Lavage Fluid as a Risk Factor Associated with the Change from Trimethoprim/sulfamethoxazole used as First-Line Treatment for Pneumocystis jirovecii Pneumonia

Background

Trimethoprim/sufamethoxazole (TMP/SMX) is the recommended treatment for Pneumocystis jirovecii pneumonia (PCP). However, the efficacy and the safety of alternative salvage treatments are less guarauteed especially when patient experiences treatment failure and/or an adverse drug reactions (ADR). The purpose of this study is to recognize potential risk factors imitating successful treatment with TMP/SMX among PCP patients.

Materials and Methods

Ninety one adult patients diagnosed with PCP were included after searching electronical medical records from January 2013 through July 2015 at Asan Medical Center Seoul, Korea. We compared clinical characteristics and laboratory findings including bronchoalveolar lavage (BAL) fluid analysis in patients who experienced TMP/SMX treatment failure or ADR (the case group) versus those who did not (the control group).

Results

Among the enrolled PCP patients, 39 (42.9%) required salvage treatment owing to either treatment failure (28, 28.6%) and/or ADR (17, 18.7%). The BAL lymphocyte percentage (25% [IQR, 8–40%] vs. 47% [IQR, 15–62%]; P = 0.005) was lower in the case group. Diabetes mellitus (adjusted odds ratio [aOR] 4.98, 95% confidence interval [95% CI] 1.20–18.58), glomerular filtration rate ≤50 mL/min (aOR 4.48, 95% CI 1.08–18.66), and BAL lymphocyte percentage ≤45% (aOR 9.25, 95% CI 2.47–34.58) were independently associated with the case group in multivariate analysis.

Conclusion

This study suggests that BAL lymphocyte count may play some role during PCP treatment. Further studies should be followed to reveal what the role of BAL lymphocyte is in the PCP treatment.

Is the Initial Size of Tuberculous Lymphadenopathy associated with Lymph Node Enlargement during Treatment?

There are little data on the changes in lymph node (LN) size during the treatment of tuberculous lymphadenopathy (TB LAP). This study aimed to provide data on LN changes during treatment. Between March 2014 and December 2015, 20 patients who were diagnosed with cervical TB LAP were enrolled. LN enlargement within two months (50%, 4/8 vs. 8.3%, 1/12; P = 0.04) was more frequently observed in patients with initial LN size ≥ 7.5 cm². Enlarged LNs were excised in three patients owing to pain and fistula formation. Initial LN size may be associated with LN enlargement during treatment.

Treatment of Methicillin-Resistant Staphylococcus aureus Bacteremia

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of health care-associated infections. Vancomycin remains an acceptable treatment option. There has been a welcome increase in the number of agents available for the treatment of MRSA infection. These drugs have certain differentiating attributes and may offer some advantages over vancomycin, but they also have significant limitations. These agents provide some alternative when no other options are available.

Clinical and economic consequences of failure of initial antibiotic therapy for patients with community-onset complicated intra-abdominal infections

Objectives

Complicated intra-abdominal infection (cIAI) is infection that extends beyond the hollow viscus of origin into the peritoneal space, and is associated with either abscess formation or peritonitis. There are few studies that have assessed the actual costs and outcomes associated with failure of initial antibiotic therapy for cIAI. The aims of this study were to evaluate risk factors and impact on costs and outcomes of failure of initial antibiotic therapy for community-onset cIAI.

Methods

A retrospective study was performed at eleven tertiary-care hospitals. Hospitalized adults with community-onset cIAI who underwent an appropriate source control procedure between August 2008 and September 2011 were included. Failure of initial antibiotic therapy was defined as a change of antibiotics due to a lack of improvement of the clinical symptoms and signs associated with cIAI in the first week.

Results

A total of 514 patients hospitalized for community-onset cIAI were included in the analysis. The mean age of the patients was 53.3 ± 17.6 years, 72 patients (14%) had health care-associated infection, and 48 (9%) experienced failure of initial antibiotic therapy. Failure of initial antibiotic therapy was associated with increased costs and morbidity. After adjustment for covariates, patients with unsuccessful initial therapy received an additional 2.9 days of parenteral antibiotic therapy, were hospitalized for an additional 5.3 days, and incurred $3,287 in additional inpatient charges. Independent risk factors for failure of initial antibiotic therapy were health care-associated infection, solid cancer, and APACHE II ≥13.

Conclusions

To improve outcomes and costs in patients with community-onset cIAI, rapid assessment of health care-associated risk factors and severity of disease, selection of an appropriate antibiotic regimen accordingly, and early infection source control should be performed.

Comparison of the clinical characteristics and outcomes of Klebsiella pneumoniae and Streptococcus pneumoniae meningitis

This multicenter, retrospective cohort study compared the clinical characteristics and outcomes of community-acquired Klebsiella pneumoniae meningitis (CA-KPM) with those of community-acquired Streptococcus pneumoniae meningitis (CA-SPM). Eighty-three adult patients, 27 with CA-KPM and 56 with CA-SPM, were included. Diabetes mellitus (48.1% versus 21.4%; P=0.01) and liver cirrhosis (22.2% versus 5.4%; P=0.05) were more commonly associated with CA-KPM. Comatose mental status (40.7% versus 12.5%; P=0.01), septic shock (44.4% versus 8.9%; P<0.001), and concomitant extrameningeal infections (40.7% versus 7.1%; P=0.001) were also more common in the CA-KPM group. The 28-day mortality (44.4% versus 10.7%; P<0.001) and inhospital mortality (51.9% versus 14.3%; P<0.001) were higher in the CA-KPM group. In conclusion, diabetes mellitus and liver cirrhosis are more common in the CA-KPM patients who were also more likely to present with severe manifestations and poor outcomes.

Oral Antimicrobial Therapy: Efficacy and Safety for Methicillin-Resistant Staphylococcus aureus Infections and Its Impact on the Length of Hospital Stay

Background

Carefully switching from intravenous to oral antibiotic therapy has shown to reduce treatment costs and lengths of hospital stay as well as increase safety and comfort in patients with infections. The aim of this study was to compare the clinical efficacy and safety between the patients treated with glycopeptides (case group), and the patients given oral antibiotics, as the initial or step-down therapy (control group), in the treatment of patients with methicillin-resistant Staphylococcus aureus (MRSA) infection.

Materials and Methods

A multicenter observational study was retrospectively performed in 7 teaching hospitals in Korea from January to December 2012. The study included adult patients (≥ 18 years) with infection caused by MRSA isolates, susceptible to clindamycin, erythromycin, and ciprofloxacin. The primary end point was treatment outcome, including all-cause mortality and switching of antibiotics. Drug-related adverse events and the lengths of hospital stay were also compared between the two treatment groups.

Results

During the study period, 107 patients (43 cases and 64 controls) with MRSA infections were enrolled from the participating hospitals. The most common sites of MRSA infection were skin and soft tissue (n = 28) and bone and joint (n = 26). The median Charlson comorbidity index (P = 0. 560), the frequency of severe sepsis (P = 0.682) or thrombocytopenia (P = 1.000), and median level of serum C-reactive protein (P = 0.157) at the onset of MRSA infections were not significantly different between the case and control groups. The oral antibiotics most frequently prescribed in the case group, were fluoroquinolones (n = 29) and clindamycin (n = 8). The median duration of antibiotic treatment (P = 0.090) and the occurrence of drug-related adverse events (P = 0.460) did not reach statistically significant difference between the two groups, whereas the total length of hospital stay after the onset of MRSA infection was significantly shorter in the case group than the control group [median (interquartile range), 23 days (8-41) vs. 32 days (15-54), P = 0.017]. In multivariate analyses, the type of antibiotic used was not an independent risk factor for treatment failure. The statistically significant factors associated with treatment failure included underlying hepatic diseases, prior receipt of antibiotics, and foreign body retention.

Conclusions

This study indicates that oral antibiotic therapy with active agents against MRSA isolates can be considered as the initial or step-down therapy for the treatment of MRSA infections and also reduce the length of hospital stay.

Risk Factors for Mortality in Patients with Acinetobacter baumannii Bacteremia

Background

Acinetobacter baumannii, an opportunistic nosocomial pathogen that can cause significant morbidity and mortality, has emerged as a worldwide problem. The aim of this study was to evaluate the risk factors for mortality in patients with A. baumannii bacteremia.

Materials and Methods

We retrospectively evaluated 118 patients who had A. baumannii bacteremia between July 2003 and December 2011. The aim of this study was to identify the 30-day mortality in patients with A. baumannii bacteremia and relevant risk factors.

Results

The bacteremia-related 30-day mortality rate was 34.1%. Univariate analysis revealed that the risk factors for mortality included malignancy, longer hospital stay before bacteremia, intensive care unit (ICU) stay at the time of bacteremia, mechanical ventilation, use of a central venous catheter, unknown origin of bacteremia, bacteremia due to pneumonia, antimicrobial resistance to carbapenems, and elevated Acute Physiology and Chronic Health Evaluation II and Pitt bacteremia scores. Multivariate logistic regression analysis revealed that resistance to carbapenems (odds ratio [OR]: 4.01, 95% confidence interval [CI]: 1.51 to 0.68, P = 0.005), need for mechanical ventilation (OR: 3.97, 95% CI: 1.41 to 11.13, P = 0.005), and presence of malignancy (OR: 4.40, 95% CI: 1.60 to 12.08, P = 0.004) were significantly related to mortality risk.

Conclusions

Risk factors such as resistance to carbapenems, mechanical ventilation, and presence of malignancy were found to be associated with high mortality rates in the patients with A. baumannii bacteremia.