Tertiary Care Hospital In South Korea Research Articles

2846. Microbiological Characteristics of the Patients with Acute Pyelonephritis who experienced Urinary Tract Infections within prior to 1 year

Abstract Background Approximately 15% of patients with acute pyelonephritis (APN) experience another urinary tract infection (UTI) within 1 year in South Korea. The purpose of this study is to examine the microbiological characteristics of patients with APN who experienced UTIs within prior to 1 year. Methods A retrospective cohort study was performed in a tertiary-care hospital in South Korea from July 2019 to December 2021. All female patients who were diagnosed with community acquired APN at admission were recruited. Patients who had prolonged hospitalization period due to medical problems that were not associated with APN treatment were excluded. We regarded recurrent group as the cases which have history of UTI within 1 year. Types of causative organism, major antibiotic resistance of E.coli isolated from patients' urine or blood, and the genetic characteristics of E.coli were compared between recurrent group and non-recurrent group. Results A total of 285 APN patients were finally included in this study, of which 41 (14.4%) were belong to recurrent group. E.coli was the most common causative pathogens in both groups, but the proportions of some pathogens, such as Klebsiella pneumonia (17.1 vs. 4.7%, P=0.007) and Pseudomonas aeruginosa (5.7 vs. 0.5%, P=0.014) were higher in the recurrent group than the non-recurrent group. There were no significant differences between the two groups in the proportions of antibiotic resistances to E.coli, such as amikacin (0 vs. 1.2%, P=0.597), cefotaxime (25.0 vs. 22.5%, P=0.788), and fluoroquinolone (20.8 vs. 28.9%, P=0.409), etc. The most prevalent β-lactamase and PMQR determinant were CTX-M-1G (44.4 vs 60.0%, P=0.308) and aac(6’)-lb-cr (50.0 vs 36.2%, P=0.303), respectively, and the predominant clone was ST131 (22.2 vs 17.8%, P=0.744) in both groups. However, there were no significant differences in the proportions of phylogenic groups, resistance genes, and virulence factors between the two groups. Conclusion E.coli was the most common causative pathogens in both groups, but the proportion of pathogens except E.coli was higher in the recurrent group than the non-recurrent group. There were no significant differences between the two groups in the proportions of antibiotic resistances to E.coli, phylogenic groups, resistance genes, and virulence factors. Disclosures All Authors: No reported disclosures

Validation of automated surveillance of healthcare-associated infections using electronic screening algorithms

Background: Surveillance of healthcare-associated infection (HAI) is the basis of infection prevention programs. However, manual review of medical records is a labor-intensive and time-consuming process. We evaluated the diagnostic performance of automated surveillance of HAI using electronic screening algorithms. Methods: Between April and June 2022, we conducted surveillance of HAI manually and automatically using electronic screening algorithm on 75 units (general medical and surgical wards and ICUs) in a 2,700-bed, tertiary-care hospital in South Korea. Algorithms for surveillance of HAI were developed accordance with NHSN surveillance definitions (Fig. 1). Catheter-associated urinary tract infections (CAUTIs) were automatically detected when eligible pathogen and fever (>38°C) were matched within infection window period. Other specific types of infection were automatically classified based on laboratory results that met NHSN criteria. After the algorithm showed possible cases that met laboratory-confirmed bloodstream infection (LCBI) criteria, we excluded secondary BSIs using the automatic surveillance algorithm. We analyzed sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the automated surveillance system compared to manual surveillance. Results: An algorithm for detecting CAUTI showed 98.7% sensitivity (78 of 79), 100.0% specificity (2,443 of 2,443), 100.0% PPV (78 of 78), and 100.0% NPV (2,443 of 2,444). For CLABSI, the algorithm had 97.3% sensitivity (214 of 220), 98.3% specificity (5,759 of 5,861), 67.7% PPV (214 of 316), and 99.9% NPV (5,759 of 5,765). In total, 102 cases of possible CLABSI were identified by the algorithm, and 76 (74.5%) were eventually diagnosed as secondary BSIs. Also, by chart review, 20 BSIs (19.6%) were present on arrival in ER (ER-POA). In 4 cases (3.9%), an original pathogen reoccurred in a repeated infection timeframe (RIT), and 2 cases (2%) were mucosal barrier injury-LCBI (MBI-LCBI). When we additionally performed manual surveillance for intra-abdominal infection secondary BSI, ER-POA, and assigning pathogen to original BSI in RIT, PPV increased to 87.7% (214 of 244). Conclusions: Algorithm for automated surveillance of CAUTI had good performance; however, automated surveillance of CLABSI was suboptimal. More elaborate screening algorithm for diagnosis CLABSI is needed, and further studies are needed to determine whether an automated surveillance system can reduce workload for surveillance of HAI.Disclosures: None

319. Clinical accuracy and utility of plasma microbial cell free DNA NGS for the diagnosis of invasive aspergillosis in patients with hematologic malignancy and COVID-19

Abstract Background Invasive aspergillosis (IA) is a great threat to the severely immunocompromised and patients with coronavirus disease (COVID-19). However, diagnosis of IA is often difficult due to need for invasive biopsy and low sensitivity of other diagnostic tests. Next-generation sequencing (NGS) of plasma cell free DNA (cfDNA) can be a novel non-invasive diagnostic modality. We evaluated the clinical accuracy and utility of microbial cfDNA NGS for the diagnosis of IA in patients with hematologic malignancy (HM) and COVID-19. Methods A single-center prospective study of plasma microbial cfDNA NGS was conducted in a tertiary-care hospital in South Korea. We enrolled adult patients with HM and COVID-19, who suspected IA and performed conventional diagnostic tests for IA. The results of NGS were compared with the diagnosis of IA through conventional methods. IA cases were diagnosed according to EORTC/MSG definitions in patients with HM, and modified AspICU criteria in patients with COVID-19. (Figure 1). Figure 1.Flow chart for the participant selection method used in this study Results Between March 2021 and January 2022, a total of 33 participants (22 [64.7%] male, median age 66.0 [50.5, 72.0]) were enrolled;19 participants with HM and 15 with COVID-19 were analyzed (Figure1 and Table1). In participants with HM, aspergillus cfDNA was detected in 100% of both proven (1/1) and probable (12/12) IA cases, and 33.3% of both possible (1/3) and no IA (1/3) cases. In participants with COVID-19, 46.2% of probable IA (6/13) showed positive aspergillus cfDNA. Detection rate of aspergillus cfDNA was significantly higher in proven/probable IA cases in participants with HM compared to participants with COVID-19. (100% vs 46.2%, p=0.005) (Figure 2). As shown in Table 2, among proven/probable IA cases, participants with positive aspergillus cfDNA showed significantly higher rate of having uncontrolled hematologic disease, receiving stem cell transplantation and recent chemotherapy. In three participants with HM, non-aspergillus strains confirmed by cfDNA NGS were in accordance with pathogens identified through conventional culture methods. Table 1.Baseline characteristics of participants suspected of invaisve aspergillosis performing microbial cell free DNA NGSFigure 2.cfDNA detection rate in participants with suspected fungal infection according to the EORTC/MSG or modified AspICU diagnostic criteria Conclusion Detection of aspergillus cfDNA showed high concordance in the results of conventional diagnostic methods in proven/probable IA of patients with HM and could be a helpful non-invasive approach to IA diagnosis in those populations. Disclosures All Authors: No reported disclosures.

435. Investigation of the cause of low measles seroprevalence among young healthcare workers in South Korea

Abstract Background After a large measles outbreak in 2000∼2001, national measles vaccination program was implemented in Korea, and more than 95% of people born after 1985 have been vaccinated with 2-dose MMR. But sporadic outbreaks have continued to occur mainly in adults in their 20’s and 30’s in 2014 and 2019. Although low prevalence in young adults have been reported, there are limited data regarding the cause of low seropositivity (positive vaccine failure vs. secondary vaccine failure). We aimed to evaluate the cause of low seroprevalence of measles. Methods This study was performed in a 2743-bed tertiary-care hospital in South Korea. At 1-month after MMR vaccination in healthcare workers (HCWs) who were seronegative for measles, we performed measles antibody test(enzyme immunoassay), IgM/IgG index ratio, and avidity test. Results Of the 1,698 new HCWs in 2020 and, 1,686 in 2021, 54 HCWs with negative measles IgG at their entering at our hospital were enrolled in this study. Of these, 36(67%) were female, and the median age was 25 (IQR, 24-27) years. Of 43 HCWs who measured IgM/IgG index 1 month after MMR vaccination, 38 HCWs had IgM/IgG index of less than 1 and remaining 5 had negative IgG results (seroconversion rate of 88%). All 54 healthcare workers who performed avidity test showed high avidity index Measles vaccination record in KCDA showed that 45 had documented vaccination record during their childhood (of these, 11 received MMR vaccine again during their adult age) and remaining 9 had no documented vaccination record during their childhood. Of these 9 healthcare workers without record in their childhood, 3 had a history of vaccination at adult. Analyzing 48 healthcare workers with vaccination record, they received MMR vaccination median 18 years (IQR, 7-20) before. Therefore, at least 48 received at least 2 dose MMR vaccination, and 11 received at least 3 dose MMR vaccination. Conclusion Secondary vaccine failure may be the reason for vaccine failure in young adults in Korea. Therefore, HCWs with negative measles antibody who were born after 1985 may receive 1 dose booster vaccination rather than 2 dose vaccination. Disclosures All Authors: No reported disclosures.

Change in the Perception of Oral Antibiotics Among Medical Students After Participating in a Parenteral-to-Oral Conversion Program for Highly Bioavailable Antibiotics.

Appropriate conversion of antibiotics from a parenteral to the oral route can lower the risk of catheter-associated infections, reduce medical costs, and shorten hospitalization. This study investigated the effect of a parenteral-to-oral conversion program for highly bioavailable antibiotics on the perceptions of medical students regarding oral antibiotics. In 2021, the parenteral-to-oral conversion program was implemented as one of the activities of an antimicrobial stewardship program at a tertiary-care hospital in South Korea. This program was also implemented for fifth-year medical students in the hospital's infectious diseases department as a core clinical practice course. Medical students reviewed the medical records of patients taking antibiotics with a high oral bioavailability and wrote a recommendation for oral conversion after confirmation by an infectious disease specialist. A survey on the perception of oral antibiotics was administered to medical students before and after clinical practice to evaluate the educational effect of the program. A total of 923 cases were reviewed, and more than one-fifth of the antibiotics with a high oral bioavailability were administered parenterally despite their oral conversion (20.6%, 190/923). Of these, 24.2% (46/190) accepted the written proposal within 48 hours, and 43.7% (83/190) declined the proposal. Through this program, students gained a proper perception of oral antibiotics. The parenteral-to-oral conversion program demonstrated an acceptance rate of oral antibiotic conversion in the hospital of 24.2% and had significant educational benefits for medical students, giving them the ability to construct an appropriate perception of oral antibiotics.

Effect of COVID-19 vaccination on transmission among healthcare workers in South Korea

Background: SARS-CoV-2 infection of healthcare workers (HCWs) occasionally occurs via acquisition from their colleagues. Data regarding the infection rates of HCWs with close contact and non–close contacts of HCWs are limited. In addition, the protective effect of COVID-19 vaccination against transmission between HCWs is unknown. We evaluated the infection rates of HCWs with close contact and non–close contact of infected HCWs and the effect of COVID-19 vaccination on transmission among HCWs in a tertiary-care hospital in South Korea. Methods: This study was performed in a tertiary-care hospital in Korea. We analyzed the COVID-19 cases and contacts among HCWs from January to December 2021. We reviewed the vaccination status of confirmed and exposed HCWs, the type of vaccination, and the infection rate according to the contact. We performed subgroup analyses in individuals who had been diagnosed since July 2021 when the δ (delta) variant became the dominant strain in South Korea. Transmission was defined based on their spatiotemporal epidemiologic association. Results: During the study period, 173 HCWs had COVID-19, and 2,693 HCWs were exposed to them. Among them, 18 (1.52%) of 1,186 close contacts and 13 (0.86%) of 1,507 non–close contacts had a positive SARS-CoV-2 test (P = .11). When the index cases had been fully vaccinated, the infection rate of close contacts was 0.85% (7 of 820), whereas the infection rate of close contacts was 3.01% (11 of 366) when the index had not been fully vaccinated (P = .005). However, the infection rate of non–close contacts was not different according to the vaccination status of index (0.83% vs 0.89%; P = .90). During the period of δ (delta) variant being dominant, the infection rate of close contacts was significantly lower when the index case had been fully vaccinated index than in cases with a non–fully vaccinated index case (0.85% vs 5.88%; P < .001). Conclusions: Transmission to colleagues was significantly lower from vaccinated HCWs than from nonvaccinated HCWs, and this finding was more significant in the era of the δ (delta) variant. Our findings support the importance of vaccination in HCWs.Funding: NoneDisclosures: None

1106. The incidence and risk factors associated with varicella zoster virus infection in kidney transplant recipients after 1-month acyclovir prophylaxis in a CMV preemptive therapy era

BackgroundVaricella zoster virus (VZV) infection is a well-known opportunistic infection in solid organ transplant recipients. Since the various strategies of the use of anti-herpetic drugs including ganciclovir or acyclovir have evolved, the epidemiology of VZV infection is changing. However, there are limited data on the recent incidence and risk factors of post-transplant VZV infection in popular preemptive ganciclovir era for CMV infection. We evaluated the incidence, risk factors and clinical characteristic of patients with development of post-transplant VZV infection in kidney transplant (KT) recipients after 1-month acyclovir prophylaxis in the hospital that adopted preemptive ganciclovir therapy for CMV infection.MethodsAll adult patients with seropositive CMV antibody admitted to a KT unit from January 2014 to December 2017 were retrospectively reviewed in a tertiary-care hospital in South Korea. Our hospital adopted preemptive ganciclovir therapy for CMV infection in all CMV seropositive KT recipients. We administered acyclovir prophylaxis for 1-month to CMV seropositive KT recipients. The primary endpoint was VZV infection development after KT.ResultsA total of 1295 KT recipients was followed up for 4295.8 person-years. The median follow-up period was 46.6 months (interquartile range (IQR) 34.3-59.5). Of the 1295 recipients, 100 (7.7%, 2.33 per 100 person-years, 95% confidence interval (CI) 1.89-2.83) patients developed VZV infection after KT. The median time for VZV infection development was 9.5 months (IQR 4.7-22.1). All patients had VZV-associated skin lesion, 9 postherpetic neuralgia, 2 visceral involvement and 3 disseminated infection. Of 100 patients, 16 patients need hospitalization due to VZV infection. In multivariate analysis, deceased donor KT (Hazard ratio (HR) 1.6; 95% CI 1.0-2.39, p = 0.05), mycophenolate maintenance immunosuppressive therapy (HR 0.3; 95% CI 0.14-0.75, p = 0.01) and rejection episode (HR 0.31; 95% CI 0.14-0.71, p = 0.01) were independently associated with VZV infection development after KT.ConclusionAbout one tenth of CMV seropositive KT recipients developed zoster after 1-month ACV prophylaxis during CMV preemptive strategy, especially in those who received deceased donor KT, mycophenolate therapy, and rejection episodes.Disclosures All Authors: No reported disclosures

Frequency of and risk factors for reversion of QuantiFERON test in healthcare workers in an intermediate-tuberculosis-burden country

ObjectivesHigh-risk healthcare workers (HCWs) are often screened for latent tuberculosis infection (LTBI) using QuantiFERON tests (QFTs), with annual serial tests often showing reversion from positive to negative results. We assessed the frequency of and risk factors for reversion of QFTs in HCWs in an intermediate-tuberculosis burden country. MethodsWe enrolled high-risk HCWs at a tertiary-care hospital in South Korea, who were assessed by QFTs at least twice between 2017 and 2019. ResultsOf the 1870 HCWs screened, 1542 (82%) had persistent negative results, 229 (12%) had persistent positive results, 53 (3%) showed reversion, and 46 (2%) showed conversion from negative to positive. Multivariate analysis comparing the characteristics of the 229 HCWs with persistent positive results and the 53 who experienced reversion showed that older age (adjusted odds ratio (aOR): 0.96; 95% confidence interval (CI): 0.92–0.99), male sex (aOR: 0.29; 95% CI: 0.11–0.78) and high (≥0.70 IU/mL) baseline QFT results (aOR: 0.15; 95% CI: 0.07–0.31) were inversely associated with reversion. Using an ROC curve-derived cut-off of <0.738 IU/mL, the area under the curve was 0.79. Of 53 HCWs with reversion, 36 (78%) had below 0.738 IU/mL of baseline QFT, while 181 (79%) of 229 HCWs without reversion had above 0.738 IU/mL of baseline QFT. ConclusionReversion during serial testing is unlikely in HCWs who are male, older in age, and have higher baseline QFT results. Serial testing without LTBI treatment may be indicated in HCWs who are female, younger and, especially, have lower QFT results.

The Utility of Preliminary Patient Evaluation in a Febrile Respiratory Infectious Disease Unit Outside the Emergency Department

Background Acute respiratory illnesses are the leading cause of death from infectious diseases around the world, and occasional outbreaks of particularly virulent strains are can be public health disasters. Recently, a large outbreak of fatal Middle East respiratory syndrome-coronavirus (MERS-CoV) occurred following a single patient exposure in the emergency department (ED) of the Samsung Medical Center, a tertiary-care hospital in South Korea, which resulted in significant public health and economic burden.After this outbreak, a febrile respiratory infectious disease unit (FRIDU) with a negative pressure ventilation system was constructed outside the emergency department (ED) in 2015, to screen for patients with contagious diseases requiring isolation.Methods This is a retrospective cohort study of patients who visited the ED with febrile illness between August 2015 and July 2016. Ultimately, 1562 patients who were hospitalized after FRIDU screening were analyzed. The level of isolation recommended during their screening at the FRIDU was compared with the level deemed appropriate given their final diagnosis.ResultsOf the 1562 patients screened at the FRIDU, 198 (13%) were isolated, 194 (12%) were reverse isolated, and 1170 (75%) were not isolated. While hospitalized, 97 patients (6%) were confirmed to have a contagious disease requiring isolation, such as tuberculosis; 207 patients (13%) were confirmed to be immunocompromised and to require reverse isolation, mainly due to neutropenia; and the remaining 1258 patients (81%) did not require isolation.The correlation coefficient for isolation consistency was 0.565 (P < 0.001). No serious nosocomial outbreaks of contagious diseases occurred. During FRIDU screening, 114 patients were admitted to the resuscitation zone due to clinical instability, and three of these patients died.Conclusion The initial isolation levels resulting from FRIDU screening were moderately well correlated with the isolation levels required by the final diagnosis, demonstrating the utility of pre-hospitalization screening units. However, the risks of deterioration during the screening process remain challenges.Disclosures All authors: No reported disclosures.

Clinical characteristics and follow-up of Korean patients with adrenal incidentalomas

Background/AimsWe investigated the clinical characteristics and follow-up findings of subjects with adrenal incidentalomas in a single, tertiary-care hospital in South Korea.MethodsThe study consisted of a retrospective analysis of 282 adrenal incidentaloma patients who underwent radiographic and endocrinological evaluations at Samsung Medical Center in Seoul, South Korea, between January 2004 and July 2011.ResultsMost (86.2%) of the subjects were found to have nonfunctioning tumors. Functioning tumors were seen in 39 patients (13.8%). Among them, 28 (9.9%) had subclinical Cushing syndrome (SCS), six (2.1%) had pheochromocytoma, and five (1.8%) had primary hyperaldosteronism. Malignant adrenal tumors were discovered in three cases: two (0.7%) were primary adrenal cancers, and one (0.4%) was a secondary metastasis from a lung cancer. Significant risk factors for functional tumors were female gender (odds ratio [OR], 3.386; 95% confidence interval [CI], 1.611 to 7.117; p = 0.0013) and a noncontrast attenuation value of > 10 Hounsfield units (OR, 2.806; 95% CI, 1.231 to 6.397; p = 0.0141). During follow-up (mean, 22.5 months) of 72 of the patients, three (4.2%) developed hormonal changes due to functional tumors. One was confirmed as pheochromocytoma by histopathology, and the others were diagnosed with SCS and followed routinely without surgical intervention. No malignant transformation was found in these patients.ConclusionsBased on these findings, initial hormonal and radiographic evaluations for adrenal incidentalomas appear to be more important than follow-up tests because functional or malignant changes are rare.

Antimicrobial Susceptibility Patterns for Recent Clinical Isolates of Anaerobic Bacteria in South Korea

We determined the antimicrobial susceptibilities of 255 clinical isolates of anaerobic bacteria collected in 2007 and 2008 at a tertiary-care hospital in South Korea. Piperacillin-tazobactam, cefoxitin, imipenem, and meropenem were highly active beta-lactam agents against most of the isolates tested. The rates of resistance of Bacteroides fragilis group organisms and anaerobic gram-positive cocci to moxifloxacin were 11 to 18% and 0 to 27%, respectively.