Shift in risk factors for mortality by period of the bloodstream infection timeline

BACKGROUND

This study was designed to determine changes in risk factors on the prognosis of patients during each period of the bloodstream infection (BSI) timeline.

METHODS

Through an integrated study of multivariable regressions with machine learning techniques, the risk factors for mortality during each period of BSI were analyzed.

RESULTS

A total of 302,303 inpatients who underwent blood cultures during 2011-2021 were enrolled. More than 8 % of BSI cases progressed to subsequent BSI, and risk factors were identified as gut colonization with vancomycin-resistant enterococci (aOR 1.82; 95 % CI 1.47-2.24), intensive care unit admission (aOR 3.37; 95 % CI 3.35-4.28), and current cancer chemotherapy (aOR 1.54; 95 % CI 1.36-1.74). The mean SOFA score of the deceased patients during the first 7 days was 10.6 (SD 4.3), which was significantly higher than those on days 8-30 (7.0 ± 4.2) and after Day 30 (4.0 ± 3.5). BSIs caused by Acinetobacter baumannii and Candida albicans were more likely to result in deaths of patients for all time periods (all, P < 0.001). BSIs caused by Enterococcus faecalis and Enterococcus faecium were associated with a poor outcome in the period after Day 30 (both, P < 0.001). Nonsusceptible phenotypes to β-lactam/β-lactamase inhibitors of Escherichia coli and Klebsiella pneumoniae influenced the prognoses of patients with BSI in terms of high mortality rates during both days 8-30 and after Day 30.

CONCLUSION

Influence of microbiological factors on mortality, including BSI-causative microorganisms and their major antimicrobial resistance, was emphasized in both periods of days 8-30 and after Day 30.

Omicron BA.2 breakthrough infection elicits CD8+ T cell responses recognizing the spike of later Omicron subvariants

Here, we examine peripheral blood memory T cell responses against the SARS-CoV-2 BA.4/BA.5 variant spike among vaccinated individuals with or without Omicron breakthrough infections. We provide evidence supporting a lack of original antigenic sin in CD8+ T cell responses targeting the spike. We show that BNT162b2-induced memory T cells respond to the BA.4/BA.5 spike. Among individuals with BA.1/BA.2 breakthrough infections, IFN-γ-producing CD8+ T cell responses against the BA.4/BA.5 spike increased. In a subgroup with BA.2 breakthrough infections, IFN-γ-producing CD8+ T cell responses against the BA.2-mutated spike region increased and correlated directly with responses against the BA.4/BA.5 spike, indicating that BA.2 spike-specific CD8+ T cells elicited by BA.2 breakthrough infection cross-react with the BA.4/BA.5 spike. We identified CD8+ T cell epitope peptides that are present in the spike of BA.2 and BA.4/BA.5 but not the original spike. These peptides are fully conserved in the spike of now-dominant XBB lineages. Our study shows that breakthrough infection by early Omicron subvariants elicits CD8+ T cell responses that recognize epitopes within the spike of newly emerging subvariants.

Intrahospital transmission and infection control of Candida auris originating from a severely infected COVID-19 patient transferred abroad

BACKGROUND

Intrahospital spread of Candida auris, which survives tenaciously in many environments, can cause sustained colonization and infection. A large outbreak of C. auris was experienced in the intensive care units (ICUs) at the study hospital during the coronavirus disease 2019 (COVID-19) pandemic.

METHODS

The index patient with severe COVID-19, who was transferred from Vietnam in January 2022, developed C. auris candidaemia 10 days after hospitalization. From mid-June 2022 to January 2023, strengthened infection prevention and control (IPC) measures were implemented in three ICUs: (1) contact precautions and isolation (CPI) for C. auris-positive cases; (2) surveillance cultures including point-prevalence (N=718) for patients or close contacts or ICU-resident healthcare workers (HCWs); (3) intensive environmental disinfection with 10-fold diluted bleach; and (4) 2% chlorhexidine bathing for all ICU patients. Environmental cultures (ECx) on surfaces and shared objects (N=276) were conducted until early September 2022, when all ECx were negative.

RESULTS

Among 53 C. auris-positive patients between February 2022 and January 2023, invasive infections resulted in seven cases of candidaemia and one case of pneumonia. C. auris was isolated from reusable tympanic thermometers (TTMs) contaminated with earwax. The isolation rate of C. auris in ECx decreased from 6.8% in June 2022 to 2.0% in August 2022, and was no longer detected in TTMs. Colonization in HCWs was remarkably rare (0.5%). The number of C. auris-positive patients peaked in July (N=10) then decreased gradually. By January 2023, no C. auris were isolated in the ICU.

CONCLUSION

Aggressive IPC measures with CPI, ECx and surveillance, decontamination of TTMs, and bathing were effective in successfully controlling this C. auris outbreak.

Clinical utility of quantitative immunoassays and surrogate virus neutralization tests for predicting neutralizing activity against the SARS-CoV-2 Omicron BA.1 and BA.5 variants

Developing new antibody assays for emerging SARS-CoV-2 variants is challenging. SARS-CoV-2 surrogate virus neutralization tests (sVNT) targeting Omicron BA.1 and BA.5 have been devised, but their performance needs to be validated in comparison with quantitative immunoassays. First, using 1749 PRNT-positive sera, we noticed that log-transformed optical density (OD) ratio of wild-type (WT) sVNT exhibited better titer-correlation with plaque reduction neutralization test (PRNT) than % inhibition value. Second, we tried 798 dilutional titration tests with 103 sera, but nonlinear correlation between OD ratio and antibody concentration limited titration of sVNT. Third, the titer-correlations of two sVNT kits for BA.1 and two quantitative immunoassays for WT were evaluated with BA.1 and BA.5 PRNT. All tested kits exhibited a linear correlation with PRNT titers, but the sVNT kits exhibited high false-negative rates (cPass-BA.1 kit, 45.4% for BA.1 and 44.2% for BA.5; STANDARD F-BA.1 kit, 1.9% for BA.1 and 2.2% for BA.5), while quantitative immunoassays showed 100% sensitivity. Linear mixed-effects model suggested superior titer-correlation with PRNT for quantitative immunoassays compared to sVNT kits. Taken together, the use of quantitative immunoassays for WT, rather than rapid development of new kits, would be practical for predicting neutralizing activities against emerging new variants.

Prevalence of carbapenemase producing Enterobacterales colonization and risk factor of clinical infection

BACKGROUND

Carbapenemase-producing Enterobacterales (CPE) are global concerns in infection control, and the number of CPE outbreaks in hospitals is increasing despite the strengthening of contact precautions. This study aimed to confirm the prevalence and transition rate of CPE infection from stool surveillance culture and to identify the acquisition pathway of CPE.

METHODS

This is a longitudinal review of patients with stool surveillance cultures at a tertiary center in Seoul, South Korea, from July 2018 to June 2020. Pulsed-field gel electrophoresis, multi-locus sequence typing, and whole genome sequencing were performed for carbapenemase-producing Klebsiella pneumoniae and Escherichia coli strains.

RESULTS

Among 1620 patients who had undergone stool CPE surveillance cultures, only 7.1% of active surveillance at the Emergency Room (ER) and 4.4% of universal surveillance in the Intensive Care Unit (ICU) were stool CPE positive. The transition rates from stool carriers to clinical CPE infections were 29.4% in the ER and 31.3% in the ICU. However, it was significantly high (55.0%) in the initial stool CPE-negative ICU patients. Among the initial stool CPE-positive patients, hypertension (61% vs. 92.3%, P = 0.004), malignancy (28.8% vs. 53.8%, P = 0.027), and mechanical ventilation (25.4% vs. 53.8%, P = 0.011) were significant risk factors for clinical CPE infection. Molecular typing revealed that sequence type (ST) 307 and ST 395 were dominant in K. pneumoniae, and ST 410 was dominant in E. coli isolates.

CONCLUSIONS

Active surveillance showed a higher detection rate than universal stool CPE screening, and one-third of positive stool CPE specimens ultimately developed subsquent clinical CPE infection. According to the molecular typing of the identified CPE strains, in-hospital spread prevailed over external inflow, and the transition rate to clinical CPE was particularly high in the ICU. Therefore, in order to control CPE propagation, not only active surveillance to block inflow from outside, but also continuous ICU monitoring within the hospital is necessary.

Differences of clinical characteristics and outcome in proven invasive Trichosporon infections caused by asahii and non-asahii species

BACKGROUND

Trichosporon is an emerging yeast that causes invasive infections in immunocompromised patients experiencing prolonged hospitalisation, indwelling venous catheters and neutropenia.

METHODS

This retrospective observational cohort study analysed invasive Trichosporon infections (ITIs) occurring between January 2005 and December 2022 at three tertiary hospitals and compared the clinical characteristics and prognostic factors of ITIs caused by Trichosporon asahii and non-T. asahii spp. After evaluating 1067 clinical isolates, we identified 46 patients with proven ITIs, defined as cases in which Trichosporon was isolated from blood, cerebrospinal fluid, or sterile tissues.

RESULTS

The patients were separated into T. asahii and non-T. asahii groups containing 25 and 21 patients, respectively, all of which except one were immunocompromised. During this period, both the number of clinical isolates and patients with ITIs (mainly T. asahii) increased; whereas, cases involving non-T. asahii spp. decreased. Compared with the non-T. asahii group, the T. asahii group had more patients with multiple catheters (84% vs. 33%, p = .001) and those receiving renal replacement therapy (48% vs. 14%, p = .005). The all-cause 28-day mortality rate after ITI in the T. asahii group (44%) was significantly higher than in the non-T. asahii group (10%, Log-rank p = .014). The multivariate Cox regression model revealed that T. asahii (reference, non-T. asahii spp.; aHR = 4.3; 95% CI = 1.2-15.2, p = .024) and neutropenia for 5 days or more (aHR = 2.2, 95% CI = 1.5-3.6, p = .035) were independent factors in the 28-day mortality after ITI.

CONCLUSION

The proven ITIs due to T. asahii produced more unfavourable outcomes compared with ITIs caused by non-T. asahii spp.

Trends, clinical characteristics, antimicrobial susceptibility patterns, and outcomes of Campylobacter bacteraemia: a multicentre retrospective study

PURPOSE

We aimed to explore the clinical characteristics of Campylobacter bacteraemia and identify the trends, risk factors for mortality, and antimicrobial susceptibility patterns from clinical samples.

METHODS

This retrospective cohort study included patients confirmed to have Campylobacter bacteraemia from seven hospitals between January 2010 and June 2021. Data on demographics and underlying history, clinical manifestation, and antimicrobial susceptibility patterns were collected and analyzed. Annual cases of Campylobacter enteritis were extracted from a public database.

RESULTS

A total of 108 patients were included, and five species were isolated. Campylobacter jejuni accounted for 54 (50.0%) cases and 17 (16%) patients had no symptoms other than fever. In-hospital mortality occurred in 14 (13.0%) patients. C. jejuni bacteraemia was associated with lower mortality compared to non-C. jejuni bacteraemia. Underlying cancer and septic shock were the significant factors associated with in-hospital mortality. Quinolone resistance was high (59%), whereas only 4% of isolates exhibited macrolide resistance. There has been a significant increase in the number of Campylobacter enteritis cases, which was strongly correlated with the number of Campylobacter bacteraemia cases (Pearson's coefficient: 0.953; p < 0.0001).

CONCLUSION

The notably increasing incidence of Campylobacter bacteraemia and antibiotic resistance patterns can challenge the treatment, necessitating collective efforts of national surveillance and networks by many departments.

Potential causal effect of contact precautions and isolation on Clostridioides difficile infection in the hyperendemic setting: Interrupted time-series analyses before and after implementation

BACKGROUND

Recent studies disputed the effectiveness of efforts to comply with contact precautions and isolation (CPI) considering relatively low intra-hospital transmission rate of healthcare facility-associated Clostridioides difficile infection (HCFA-CDI). We evaluated the potential causal effect of CPI on HCFA-CDI occurrence by comparing the incidence rate (IR) for different time periods with and without CPI implementation.

METHODS

Long-term observational time-series data were separated into three periods (pre-CPI: January 2012-March 2016, CPI: April 2016-April 2021, post-CPI: May 2021-December 2022). CPI was suspended owing to the restriction of isolation rooms during the COVID-19 pandemic. We inferred potential causal outcomes by comparing predicted and observed IRs of HCFA-CDI using interrupted time-series analyses, including the Bayesian structural time-series or autoregressive integrated moving average (ARIMA) model in the R-language or SAS software.

RESULTS

The monthly observed IR (44.9/100,000 inpatient-days) during the CPI period was significantly lower than the predicted IR (90.8) (-50.6% relative effect, P = 0.001). However, the observed IR (52.3) during the post-CPI period was significantly higher than the predicted IR (39.1) (33.6%, P = 0.001). The HCFA-CDI IR decreased during CPI (-14.3, P < 0.001) and increased post-CPI (5.4, P < 0.001) in the multivariable ARIMA model, which controlled for antibiotic usage, handwashing with soap and water, and number of toxin tests.

CONCLUSIONS

Various time-series models revealed that CPI implementation had a potential causal effect on the reduction of HCFA-CDI incidence.

Association of body mass index and bloodstream infections in patients on extracorporeal membrane oxygenation: a single-centre, retrospective, cohort study

BACKGROUND

Obesity is associated with poor clinical outcomes in critically ill patients. However, under some clinical conditions, obesity has protective effects. Bloodstream infections (BSI) are among the most common nosocomial infections associated with extracorporeal membrane oxygenation (ECMO). BSI during ECMO is associated with higher mortality rates and poorer clinical outcomes.

AIM

To analyse whether body mass index (BMI) is associated with BSI during ECMO or with in-hospital mortality.

METHODS

All adult patients who had received ECMO support for >48 h were included in the analysis. The analysis of total duration of ECMO support, in-hospital mortality and BSI was stratified by BMI category. The Cox proportional hazards model was used to compare the risk of BSI among BMI categories.

FINDINGS

In total, 473 patients were enrolled in the study. The average age was 56.5 years and 65.3% were men. The total duration of ECMO was approximately 11.8 days, with a mortality rate of 47.1%. The incidence rates of BSI and candidaemia were 20.5% and 5.5%, respectively. The underweight group required ECMO for respiratory support, whereas the overweight and obese groups required ECMO for cardiogenic support (P<0.0001). No significant difference in BSI rate was found (P=0.784). However, after adjusting for clinical factors, patients in Group 4 (BMI 25.0-<30.0 kg/m2) exhibited lower mortality compared with patients in Group 2 (normal BMI) (P=0.004).

CONCLUSION

BMI was not associated with risk of BSI, but patients with higher BMI showed lower in-hospital mortality associated with ECMO support.

Long-term prognosis and overall mortality in patients with progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) is a rare but fatal opportunistic infection and mainly occurs in patients with immunosuppressive conditions. Despite the increasing number of patients receiving immunosuppressive treatments, studies on PML are still lacking due to its low prevalence and incidence. We retrospectively reviewed patients diagnosed with PML in two tertiary hospitals in South Korea from 1999 to 2021. Total of 47 PML patients were included. Of 27 patients (57.4%) were diagnosed with human immunodeficiency virus (HIV). Median last follow-up modified Rankin Scale (mRS) score was higher in the non-HIV PML group than that in the HIV group (5 vs. 4, p = 0.020). Median survival duration was lower in the non-HIV group (184 vs. 1,564 days). The 1-year and overall mortality rates of PML patients were significantly higher in the non-HIV group than that in HIV group (60.0% vs. 25.9%, p = 0.019; 80.0% vs. 40.7%, p = 0.007). Initial mRS score (HR 1.685, p = 0.038) and highly active antiretroviral therapy (HAART) in HIV patients (HR 0.374, p = 0.013) had a significant effect on overall mortality. Our findings suggest that early detection of PML with low mRS score and early initiation of HAART in patients with HIV may improve prognosis.

Midline catheters in the operating room

Backgrounds

Among various vascular access devices, midline catheters (MCs) are commonly used in emergency departments, but rarely in operating rooms.

Aims

To evaluate the feasibility and safety of MCs in the operating room.

Materials and Methods

This was a retrospective study. The medical records of patients who underwent MC placement in the operating room from October 2020 to July 2022 were reviewed. The rates of successful catheter insertion as well as major and minor complications were assessed.

Results

Successful catheter insertions were achieved in 149 of 161 patients (92.5%). The median dwell time of midlines was eight days (IQR: 6-10 days). A major or minor complication occurred in 6.7% of the midlines. The rates of major complications of occlusion, upper extremity deep vein thrombosis (DVT), and catheter-related bloodstream infection were 1.3%, 0.7%, and 0%, respectively.

Conclusions

Placement of MCs in the operating room was feasible and safe. Also, the procedure provides an acceptable alternative for replacing central line catheters and peripherally inserted central catheters.

[Evaluation of right ventricular function using two-dimensional speckle tracking echocardiography and analysis of the risk factors for right ventricular dysfunction in patients with silicosis]

Objective: To evaluate the right ventricular function using two-dimensional speckle tracking echocardiography (2-D STE) and analyze the associated risk factors of right ventricular dysfunction in patients with silicosis. Methods: All 104 patients with silicosis treated in the Department of Occupational Medicine and Toxicology in Beijing Chao-Yang Hospital, Capital Medical University from May 2021 to September 2022 were enrolled in this study in October 2022. The clinical information of patients such as general data, arterial blood gas analysis and pulmonary function test were collected. The right ventricular function of patients was evaluated by 2-D STE-derived right ventricular free wall longitudinal strain (RVFWLS) and conventional echocardiographic-derived parameters, including right ventricular fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE) and doppler tissue imaging-derived tricuspid lateral annular systolic velocity (S'), respectively. Based on their RVFWLS, the patients were divided into right ventricular dysfunction group and normal right ventricular function group. Risk factors for right ventricular dysfunction in patients with silicosis were analyzed using binary logistic regression analysis. Results: A total of 104 silicosis patients were enrolled, with aneverage age (65.52±11.18) years old, among whom including 57 cases diagnosed with stage Ⅰ/Ⅱ silicosis and 47 cases diagnosed with stage Ⅲ silicosis. 26 (25.00%) patients concurrent right ventricular dysfunction. The abnormal rates of RVFAC, TAPSE and S' in patients were 16.35% (17 cases), 21.15% (22 cases) and 6.73% (7 cases), respectively. The RVFAC and TAPSE in right ventricular dysfunction group were lower than those in normal right ventricular function group, and the incidence of pulmonary arterial systolic pressure ≥36 mmHg was higher than that in normal right ventricular function group (P<0.05). Logistic regression analysis showed that arterial partial pressure of oxygen (OR=0.932, 95%CI: 0.885-0.981, P=0.007) was the protective factor, and the forced expiratory volume in 1 second (FEV(1)) /forced vital capacity (FVC) ratio<70% (OR=5.484, 95%CI: 1.049-28.662, P=0.044) and stage Ⅲ silicosis (OR=6.343, 95%CI: 1.698-23.697, P=0.007) were the risk factors for silicosis patients concurrent right ventricular dysfunction. Conclusion: The incidence of right ventricular dysfunction is higher in patients with stage Ⅲ silicosis than that in patients with stage Ⅰ/Ⅱ silicosis. Using 2-D STE can help the early detection of silicosis with right ventricular dysfunction. Hypoxemia, airflow limitation and the stage Ⅲ silicosis are the risk factors for silicosis patients concurrent right ventricular dysfunction.

Immune Response Kinetics Following a Third Heterologous BNT162b2 Booster Dose After Primary 2-Dose ChAdOx1 Vaccination in Relation to Omicron Breakthrough Infection: A Prospective Nationwide Cohort Study in South Korea

Background

Immune responses to each vaccine must be investigated to establish effective vaccination strategies for the ongoing coronavirus disease (COVID-19) pandemic. We investigated the long-term kinetics of immune responses after heterologous booster vaccination in relation to Omicron breakthrough infection (BI).

Methods

Our study included 373 healthcare workers who received primary ChAdOx1 vaccine doses and a third BNT162b2 vaccine dose. BIs that occurred after the third vaccine were investigated. Blood specimens were collected before and 3 months after the booster dose from participants without BI and 1, 4, and 6 months after BI from participants who experienced BI. Spike-specific binding and neutralizing antibody levels against the wild-type virus, Omicron BA.1, and Omicron BA.5, as well as cellular responses, were analyzed.

Results

A total of 346 participants (82 in the no BI group; 192 in the BI group during the BA.1/BA.2 period; 72 in the BI group during the BA.5 period) were included in the analysis. Participants without BI exhibited the highest binding and neutralizing antibody concentrations and greatest cellular response 1 month after the third vaccination, which reached a nadir by the ninth month. Antibody and cellular responses in participants who experienced BI substantially increased postinfection. Neutralizing antibody titers in individuals who experienced BI during the BA.1/BA.2 period showed more robust increase against wild-type virus than against BA.1 and BA.5.

Conclusions

Our findings provide evidence of antigenic imprinting in participants who received a heterologous booster vaccination, thereby serving as a foundation for further studies on the impact of BIs on immune responses.

Novel Mutations Conferring Amoxicillin Resistance in Helicobacter pylori in South Korea

Helicobacter pylori is the primary causative agent of gastritis, gastric ulcers, duodenal ulcers, gastric cancer, and peripheral B-cell lymphoma. H. pylori eradication often fails due to elevated antibiotic resistance. However, no previous studies have thoroughly examined amoxicillin resistance. Here, the objective was to identify clinical strains of H. pylori with amoxicillin resistance and to analyze single-nucleotide polymorphisms (SNPs) associated with amoxicillin resistance. From March 2015 to June 2019, genotypic and phenotypic amoxicillin resistance was analyzed using an E-test and whole-genome sequencing (WGS). Analysis of 368 clinical strains confirmed amoxicillin resistance in 31 strains (resistance rate of 8.7%). The genomes were extracted from nine resistant (<0.125 mg/L) strains, and WGS was performed for genetic analysis. WGS analysis identified SNPs present in pbp1a, pbp2, nhaC, hofH, hofC, and hefC in all nine isolates. Some of these genes may be related to amoxicillin resistance. A total of six SNPs (A69V, V374L, S414R, T503I, A592D, and R435Q) were identified in PBP2 of H-8, the most resistant strain. We predict that these six SNPs are associated with high amoxicillin resistance. Amoxicillin resistance should be considered in the clinical setting for the treatment failure of H. pylori eradication.

Immunogenicity Differences of the ChAdOx1 nCoV-19 Vaccine According to Pre-Existing Adenovirus Immunity

This study investigated the immunogenicity of, and reactogenicity to, the ChAdOx1 nCoV-19 vaccine according to pre-existing adenovirus immunity. Individuals scheduled for COVID-19 vaccination were prospectively enrolled in a tertiary hospital with 2400 beds from March 2020 onwards. Pre-existing adenovirus immunity data was obtained before ChAdOx1 nCoV-19 vaccination. A total of 68 adult patients administered two doses of the ChAdOx1 nCoV-19 vaccine were enrolled. Pre-existing adenovirus immunity was identified in 49 patients (72.1%), but not in the remaining 19 patients (27.9%). The geometric mean titer of S-specific IgG antibodies was statistically higher in individuals without pre-existing adenovirus immunity at several time points: before the second ChAdOx1 nCoV-19 dose (56.4 (36.6–125.0) vs. 51.0 (17.9–122.3), p = 0.024), 2–3 weeks after the second ChAdOx1 nCoV-19 dose (629.5 (451.5–926.5) vs. 555.0 (287.3–926.0), p = 0.049), and 3 months after the second ChAdOx1 nCoV-19 dose (274.5 (160.5–655.3) vs. 176.0 (94.3–255.3), p = 0.033). In the absence of pre-existing adenovirus immunity, systemic events were observed with higher frequency, especially chills (73.7% vs. 31.9%, p = 0.002). In conclusion, individuals without pre-existing adenovirus immunity showed a higher immune response to ChAdOx1 nCoV-19 vaccination and a higher frequency of reactogenicity to ChAdOx1 nCoV-19 vaccination was observed.

Estimation of SARS-CoV-2 Neutralizing Activity and Protective Immunity in Different Vaccine Types Using Three Surrogate Virus Neutralization Test Assays and Two Semiquantitative Binding Assays Targeting the Receptor-Binding Domain

Estimating neutralizing activity in vaccinees is crucial for predicting the protective effect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As the plaque reduction neutralization test (PRNT) requires a biosafety level 3 facility, it would be advantageous if surrogate virus neutralization test (sVNT) assays and binding assays could predict neutralizing activity. Here, five different assays were evaluated with respect to the PRNT in vaccinees: three sVNT assays from GenScript, Boditech Med, and SD Biosensor and two semiquantitative binding assays from Roche and Abbott. The vaccinees were subjected to three vaccination protocols: homologous ChAdOx1, homologous BNT162b2, and heterologous administration. The ability to predict a 50% neutralizing dose (ND50) of ≥20 largely varied among the assays, with the binding assays showing substantial agreement (kappa, ~0.90) and the sVNT assays showing relatively poor performance, especially in the ChAdOx1 group (kappa, 0.33 to 0.97). The ability to predict an ND50 value of ≥118.25, indicating a protective effect, was comparable among different assays. Applying optimal cutoffs based on Youden's index, the kappa agreements were greater than 0.60 for all assays in the total group. Overall, relatively poor performance was demonstrated in the ChAdOx1 group, owing to low antibody titers. Although there were intra-assay differences related to the vaccination protocols, as well as interassay differences, all assays demonstrated fair performance in predicting the protective effect using the new cutoffs. This study demonstrates the need for a different cutoff for each assay to appropriately determine a higher neutralizing titer and suggests the clinical feasibility of using various assays for estimation of the protective effect. IMPORTANCE The coronavirus disease 2019 (COVID-19) pandemic continues to last, despite high COVID-19 vaccination rates. As many people experience breakthrough infection after prior infection and/or vaccination, estimating the neutralization activity and predicting the protective effect are major issues of concern. However, since standard neutralization tests are not available in most clinical laboratories, it would be beneficial if commercial assays could predict these aspects. In this study, we evaluated the performance of three sVNT assays and two semiquantitative binding assays targeting the receptor-binding domain with respect to the PRNT. Our results suggest that these assays could be used for predicting the protective effect by adjusting the cutoffs.

2311. Long-term prognosis and risk factors for overall mortality in patients with progressive multifocal leukoencephalopathy

Background

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by reactivation of JC virus, almost in patients with immunosuppressive conditions. PML is a fatal infection with a reported 3-month mortality rate of 30–50% and a 2-month mortality rate of up to 90% in the non-human immunodeficiency virus (HIV) population. Despite high mortality, studies on PML are still lacking due to its low prevalence and incidence. Therefore, this study aimed to figure out long-term prognosis of PML and prognostic factors for mortality through a long observation period.

Methods

We retrospectively reviewed 68 PML patients with admitted to two tertiary hospitals in South Korea from 1999 to 2021. A total of 47 PML patients were finally enrolled after exclusion. The primary endpoint was long-term overall mortality. For survival analysis, Kaplan-Meier curve and Cox proportional hazards model were used. Each patient was followed up until death or until the end of the study period, whichever came first.

Results

The median follow-up duration was 20 (interquartile range [IQR], 3–79) months. The median age was 46 years, 27 (57.4%) were diagnosed with HIV, 19 (40.4%) were using immunosuppressive drugs. The median last follow-up modified Rankin Scale (mRS) was higher in non-HIV PML patients group (5 [IQR, 4–6] vs 4 [IQR, 2–5], p=0.020). The median survival duration was 184 (IQR 74–1,566) days in the non-HIV group and 1,564 (IQR 254–3,444) days in the HIV group. The overall mortality rate of PML patients was significantly higher in non-HIV group (80.0% vs 40.7%, p=0.007), also confirmed by the Kaplan-Meier curve and log-rank test (p=0.007). Initial mRS (HR 1.685, 95% CI: 1.028–2.762, p=0.038), HIV patients with highly active antiretroviral therapy (HAART) (HR 0.374, 95% CI: 0.172–0.815, p=0.013) had a significant effect on overall mortality.

Conclusion

With the widespread adoption of HAART, the survival duration of HIV patients with PML has been extended, but the mortality rate is still high. Also, the prognosis for PML in non-HIV patients is still frustrated. Initial mRS is a significant risk factor for long-term overall mortality in PML patients. Early detection of PML and early initiation of HAART in HIV patients may improve the patient's prognosis.

Disclosures

All Authors: No reported disclosures.

Reactogenicity and Immunogenicity of the ChAdOx1 nCOV-19 Coronavirus Disease 2019 Vaccine in South Korean Healthcare Workers

PURPOSE

The association between reactogenicity and immunogenicity of the ChAdOx1 nCOV-19 is controversial. We aimed to evaluate this association among South Korean healthcare workers (HCWs).

MATERIALS AND METHODS

Participants received two doses of the ChAdOx1vaccine 12 weeks apart. Blood samples were tested for anti-severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) spike protein receptor binding domain antibodies about 2 months after the first and second doses using the Elecsys Anti-SARS-CoV-2 S assay kits. Adverse events were noted using an online self-reporting questionnaire.

RESULTS

Among the 232 HCWs, pain (85.78% after the first dose vs. 58.62% after the second dose, p<0.001) was the most prominent local reaction, and myalgia or fatigue (84.05% vs. 53.02%, p<0.001) was the most prominent systemic reaction. The frequency of all adverse events was significantly reduced after the second dose. After the first dose, the anti-SARS-CoV-2 S showed significantly higher titer in the group with swelling, itching, fever, and nausea. Also, the anti-SARS-CoV-2 S titer significantly increased as the grade of fever (p=0.007) and duration of fever (p=0.026) increased; however, there was no significant correlation between immunogenicity and adverse event after the second dose. The group with pain after the first dose showed a greater increase in the anti-SARS-CoV-2 S difference between the second and first doses compared to the group without pain (542.2 U/mL vs. 363.8 U/mL, p=0.037).

CONCLUSION

The frequency of adverse events occurring after the first dose of the ChAdOx1 was significantly reduced after the second dose. Interestingly, the elevation of anti-SARS-CoV-2 S titer was significantly increased in the group with pain after the first dose.

Kinetics of vaccine-induced neutralizing antibody titers and estimated protective immunity against wild-type SARS-CoV-2 and the Delta variant: A prospective nationwide cohort study comparing three COVID-19 vaccination protocols in South Korea

Introduction

Despite vaccine development, the COVID-19 pandemic is ongoing due to immunity-escaping variants of concern (VOCs). Estimations of vaccine-induced protective immunity against VOCs are essential for setting proper COVID-19 vaccination policy.

Methods

We performed plaque-reduction neutralizing tests (PRNTs) using sera from healthcare workers (HCWs) collected from baseline to six months after COVID-19 vaccination and from convalescent COVID-19 patients. The 20.2% of the mean PRNT titer of convalescent sera was used as 50% protective value, and the percentage of HCWs with protective immunity for each week (percent-week) was compared among vaccination groups. A correlation equation was deduced between a PRNT 50% neutralizing dose (ND50) against wild type (WT) SARS-CoV-2 and that of the Delta variant.

Results

We conducted PRNTs on 1,287 serum samples from 297 HCWs (99 HCWs who received homologous ChAdOx1 vaccination (ChAd), 99 from HCWs who received homologous BNT162b2 (BNT), and 99 from HCWs who received heterologous ChAd followed by BNT (ChAd-BNT)). Using 365 serum samples from 116 convalescent COVID-19 patients, PRNT ND50 of 118.25 was derived as 50% protective value. The 6-month cumulative percentage of HCWs with protective immunity against WT SARS-CoV-2 was highest in the BNT group (2297.0 percent-week), followed by the ChAd-BNT (1576.8) and ChAd (1403.0) groups. In the inter-group comparison, protective percentage of the BNT group (median 96.0%, IQR 91.2–99.2%) was comparable to the ChAd-BNT group (median 85.4%, IQR 15.7–100%; P =0.117) and significantly higher than the ChAd group (median 60.1%, IQR 20.0–87.1%; P &lt;0.001). When Delta PRNT was estimated using the correlation equation, protective immunity at the 6-month waning point was markedly decreased (28.3% for ChAd group, 52.5% for BNT, and 66.7% for ChAd-BNT).

Conclusion

Decreased vaccine-induced protective immunity at the 6-month waning point and lesser response against the Delta variant may explain the Delta-dominated outbreak of late 2021. Follow-up studies for newly-emerging VOCs would also be needed.

Clinical and microbiological characteristics of and risk factors for bloodstream infections among patients with extracorporeal membrane oxygenation: a single-center retrospective cohort study

Extracorporeal membrane oxygenation (ECMO) provides hemodynamic and oxygenation support to critically ill patients. Due to multiple catheter cannulations, patients on ECMO are vulnerable to bloodstream infections (BSIs). We aimed to investigate the incidence, clinical characteristics, risk factors, and microorganisms associated with BSIs during ECMO. This single-center retrospective cohort study was conducted between January 2015 and May 2021. Patients aged 18 years or older with an ECMO duration of > 48 h for cardiogenic or respiratory support were included in the study. Patients who developed bacteremia or candidemia from 12 h after ECMO cannulation to 7 days after de-cannulation were included. The clinical factors between non-BSI and BSI were compared, along with an analysis of the risk factors associated with BSI during ECMO. A total of 480 patients underwent ECMO for cardiogenic shock (n = 267, 55.6%) or respiratory failure (n = 213, 44.4%) during the study period. The incidence was 20.0 episodes per 1000 ECMO-days. Approximately 20.2% (97/480) and 5.4% (26/480) of the patients developed bacteremia and candidemia, respectively. The median numbers of days of BSI development were 8.00 days for bacteremia and 11.0 days for candidemia. The most common pathogens were methicillin-resistant coagulase-negative staphylococci (n = 24), followed by vancomycin-resistant Enterococcus (n = 21). Multivariable logistic analysis demonstrated that hemodialysis (odds ratio [OR] 2.647, p < 0.001), veno-arterial-venous mode (OR 1.911, p = 0.030), and total ECMO duration (OR 1.030, p = 0.007) were significant risk factors for bacteremia. The total ECMO duration was the only risk factor associated with candidemia (OR 1.035, p = 0.010). The mortality rate was significantly higher in the bacteremia (57.7%) and candidemia (69.2%) groups than that in the non-BSI group (43.6%). BSI is a common complication of patients receiving ECMO support and is associated with poor clinical outcomes. Determining the type of frequently isolated organisms and the median onset time of BSI would help in the selection of appropriate prophylactic antibiotics or antifungal agents.

The impact of sarcopenia on short-term and long-term mortality in patients with septic shock

BACKGROUND

Despite medical advances, septic shock remains one of the main causes of high mortality in critically ill patients. Although sarcopenia is considered a predictor of mortality in septic shock patients, most studies have only investigated short-term mortality, and those on long-term prognosis are limited. We investigated the impact of sarcopenia on long-term mortality in a large patient population with septic shock.

METHODS

A retrospective cohort study comprising 905 patients with septic shock was conducted from 2008 to 2019. Sarcopenia was defined based on the measurement of the total abdominal muscle area, assessed using abdominal computed tomography scans. Thereafter, we stratified the patients into two groups-sarcopenia and non-sarcopenia groups-and compared the impact of sarcopenia on short-term (28 days) and long-term (1 year and overall) mortality using multivariable Cox proportional analysis.

RESULTS

A total of 905 patients were included, and the mean age was 65.7 ± 15.1 years. Among them, 430 (47.5%) patients were male and 407 (45.0%) had sarcopenia. We found that the 28 day, 1 year, and overall mortality rates in the sarcopenia group were significantly higher than those in the non-sarcopenia group (13.8% vs. 6.4%, P < 0.001; 41.8% vs. 21.7%, P < 0.001; 62.2% vs. 35.7%, P < 0.001, respectively). Univariable Cox analysis showed that the sarcopenia group had a significant association with the increase in each mortalities compared with the non-sarcopenia group (28 day mortality, hazard ratio (HR) = 2.230, 95% confidence interval (CI) [1.444-3.442], P < 0.001; 1 year mortality, HR = 2.189, 95% CI [1.720, 2.787], P < 0.001; overall mortality, HR = 2.254, 95% CI [1.859, 2.734], P < 0.001). Multivariable Cox analysis showed that both the short-term and long-term mortality rates remained significantly higher in the sarcopenia group than in the non-sarcopenia group, even after adjusting for confounding variables (28 day mortality, HR = 2.116, 95% CI [1.312, 3.412], P = 0.002; 1 year mortality, HR = 1.679, 95% CI [1.291, 2.182], P < 0.001; overall mortality, HR = 1.704, 95% CI [1.381, 2.102], P < 0.001).

CONCLUSIONS

Sarcopenia was associated with both short-term and long-term mortality in patients with septic shock. In clinical settings, close attention should be paid to these patients for both short-term and long-term outcomes.

[Four cases of acute ethylene glycol poisoning]

Ethylene glycol is the main component of antifreeze, due to its special sweetness, it is easy to cause misuse. In this paper, the clinical data of 4 cases of acute ethylene glycol poisoning admitted to Beijing Chao-Yang Hospital from August 2016 to August 2021 were retrospectively analyzed to explore the clinical characteristics of acute ethylene glycol poisoning cases. Early and accurate assessment of the disease and early hemodialysis treatment is the key to cure acute ethylene glycol poisoning.

[Clinical features and follow-up outcomes of optic nerve injury induced by acute methanol poisoning]

Acute methanol poisoning harms the optic nerve and central nervous system, can cause irreversible damage, even coma or death in severe cases. This article reported four cases of methanol poisoning. 3 patients mistakenly ingested industrial alcohol containing methanol, the most serious patient suffered from coma, vision loss and other symptoms, the blood methanol concentration was 869.3 μg/ml. Another patient was poisoning caused by inhalation of methanol, with symptoms such as total blindness in the right eye and decreased visual acuity in the left eye. After active supportive treatment, 2 patients had partial recovery of visual acuity, and 2 patients had no sequelae. This article discussed the clinical features, treatment and prognosis of optic nerve damage caused by methanol poisoning, in order to raise awareness of this disease.

Heterologous ChAdOx1 and BNT162b2 vaccination induces strong neutralizing antibody responses against SARS-CoV-2 including delta variant with tolerable reactogenicity

OBJECTIVES

We assessed humoral responses and reactogenicity following the heterologous vaccination compared to the homologous vaccination groups.

METHODS

We enrolled healthcare workers (HCWs) who were either vaccinated with ChAdOx1 followed by BNT162b2 (heterologous group) or two doses of ChAdOx1 (ChAdOx1 group) or BNT162b2 (BNT162b2 group). Immunogenicity was assessed by measuring antibody titers against receptor-binding domain (RBD) of SARS-CoV-2 spike protein in all participants and neutralizing antibody titer in 100 participants per group. Reactogenicity was evaluated by a questionnaire-based survey.

RESULTS

We enrolled 499 HCWs (ChAdOx1, n=199; BNT162b2, n=200; heterologous ChAdOx1/BNT162b2, n=100). The geometric mean titer of anti-RBD antibody at 14 days after the booster dose was significantly higher in the heterologous group (11780.55 BAU/mL [95% CI, 10891.52-12742.14]) than in the ChAdOx1 (1561.51 [1415.03-1723.15]) or BNT162b2 (2895.90 [2664.01-3147.98]) groups (both P value<.001). The neutralizing antibody titer of the heterologous group (geometric mean ND_50, 2367.74 [1970.03-2845.74]) was comparable to that of the BNT162b2 group (2118.63 [1755.88-2556.32], P >.05) but higher than that of the ChAdOx1 group (391.77 [326.16-470.59], P value<.001). Compared with those against wild-type SARS-CoV-2, the geometric mean neutralizing antibody titers against the delta variant at 14 days after the boosting were reduced by 3.0-fold in the heterologous group (geometric mean ND_50. 872.01 [95% CI, 685.33-1109.54]), 4.0-fold in the BNT162b2 group (337.93 [262.78-434.57]), and 3.2-fold in the ChAdOx1 group (206.61 [144.05-296.34]). The local or systemic reactogenicity after the booster dose in the heterologous group was higher than that of the ChAdOx1 group but comparable to that of the BNT162b2 group.

CONCLUSIONS

Heterologous ChAdOx1 followed by BNT162b2 vaccination with a 12-week interval induced a robust humoral immune response against SARS-CoV-2 including the delta variant that was comparable to the homologous BNT162b2 vaccination and stronger than the homologous ChAdOx1 vaccination, with a tolerable reactogenicity profile.

[Study on the difference of curative effect of conventional mercury displacement treatment on mercury in brain and kidney]

Objective: To explore the expulsion effect of sodium dimercaptopropanesulfonate (DMPS) on mercury in different organs of mercury poisoning and the therapeutic effect of glutathione (GSH) combined with antioxidant therapy on mercury poisoning. Methods: In February 2019, 50 SPF male SD rats were randomly divided into 5 groups, 10 rats in each group: A (saline negative control group) , B (HgCL2 positive control group) , treatment group (C: intramuscular injection of DMPS 15 mg/kg treatment, D: intramuscular injection of DMPS30 mg/kg treatment, E: intramuscular injection of DMPS 15 mg/kg and intraperitoneal injection of GSH200 mg/kg treatment) . Rats in group B, C, D and E were subcutaneously injected with mercury chloride solution (1 mg/kg) to establish a rat model of subacute mercury poisoning kidney injury. Rats in group A were subcutaneously injected with normal saline. After the establishment of the model, rats in the treatment group were injected with DMPS and GSH. Rats in group A and group B were injected with normal saline. At 21 d (treatment 7 d) and 28 d (treatment 14 d) after exposure, urine and blood samples of 5 rats in each group were collected. Blood biochemistry, urine mercury, urine microalbumin and mercury content in renal cortex, cerebral cortex and cerebellum were detected. Results: After exposure to mercury, the contents of mercury in renal cortex, cerebrum and cerebellum of rats in group B, C, D and E increased, and urine microalbumin increased. Pathology showed renal tubular injury and renal interstitial inflammation. Compared with group B, urinary mercury and renal cortex mercury in group C, D and E decreased rapidly after DMPS treatment, and there was no significant decrease in mercury levels in cerebellum and cerebral cortex of rats, accompanied by transient increase in urinary albumin after DMPS treatment (P<0.05) ; the renal interstitial inflammation in group E was improved after GSH treatment. There was a positive correlation between urinary mercury and the contents of mercury in renal cortex, cerebral cortex and cerebellum (r=0.61, 0.47, 0.48, P<0.05) . Conclusion: DMPS mercury expulsion treatment can significantly reduce the level of metal mercury in the kidney, and there is no significant change in the level of metal mercury in the cortex and cerebellum.

Safety and immunogenicity of two recombinant DNA COVID-19 vaccines containing the coding regions of the spike or spike and nucleocapsid proteins: an interim analysis of two open-label, non-randomised, phase 1 trials in healthy adults

Background

We assessed the safety and immunogenicity of two recombinant DNA vaccines for COVID-19: GX-19 containing plasmid DNA encoding the SARS-CoV-2 spike protein, and GX-19N containing plasmid DNA encoding the SARS-CoV-2 receptor-binding domain (RBD) foldon, nucleocapsid protein, and plasmid DNA encoding the spike protein.

Methods

Two open-label non-randomised phase 1 trials, one of GX-19 and the other of GX-19N were done at two hospitals in South Korea. We enrolled healthy adults aged 19–49 years for the GX-19 trial and healthy adults aged 19–54 years for the GX-19N trial. Participants who tested positive by serological testing for SARS-CoV-2 were excluded. At 4-week intervals, the GX-19 trial participants received two vaccine doses (either 1·5 mg or 3·0 mg), and the GX-19N trial participants received two 3·0 mg doses. The vaccines were delivered intramuscularly using an electroporator. The participants were followed up for 52 weeks after first vaccination. Data collected up to day 57 after first vaccination were analysed in this interim analysis. The primary outcome was safety within 28 days after each vaccination measured in the intention-to-treat population. The secondary outcome was vaccine immunogenicity using blood samples collected on day 43 or 57 after first vaccination measured in the intention-to-treat population. The GX-19 (NCT044445389) and GX-19N (NCT04715997) trials are registered with ClinicalTrials.gov.

Findings

Between June 17 and July 30, 2020, we screened 97 individuals, of whom 40 (41%) participants were enrolled in the GX-19 trial (20 [50%] in the 1·5 mg group and 20 [50%] in the 3·0 mg group). Between Dec 28 and 31, 2020, we screened 23 participants, of whom 21 (91%) participants were enrolled on the GX-19N trial. 32 (52%) of 61 participants reported 80 treatment-emergent adverse events after vaccination. All solicited adverse events were mild except one (2%) case of moderate fatigue in the 1·5 mg GX-19 group; no serious vaccine-related adverse events were detected. Binding antibody responses increased after second dose of vaccination in all groups (p=0·0002 in the 1·5 mg GX-19 group; p<0·0001 in the 3·0 mg GX-19; and p=0·0004 for the spike protein and p=0·0001 for the RBD in the 3·0 mg GX-19N group).

Interpretation

GX-19 and GX-19N are safe and well tolerated. GX-19N induces humoral and broad SARS-CoV-2-specific T-cell responses. GX-19N shows lower neutralising antibody responses and needs improvement to enhance immunogenicity.

Funding

The Korea Drug Development Fund, funded by the Ministry of Science and ICT, Ministry of Trade, Industry, and Energy, and Ministry of Health and Welfare.

Risk Factors Affecting Complications of Access Site in Vascular Intervention through Common Femoral Artery

Backgrounds

Traditionally, vascular interventions have been performed through the femoral artery.

Aims

The purpose of this study was to evaluate risk factors affecting access-site complications in patients with hepatocellular carcinoma or peripheral arterial disease in lower extremity who underwent vascular intervention by accessing the common femoral artery (CFA).

Patients and Methods

From December 2015 to November 2018, 287 patients underwent transarterial chemoembolization (TACE) or peripheral vascular intervention with ultrasound (US)-guided CFA access. Standard 18-gauge (G) access was used in 127 patients and Micropuncture® 21-G needles in 160 patients. Most access sites were managed with vascular closure devices and several were managed with manual compression. Within 24 hours after the procedure, all patients underwent US to evaluate the puncture site.

Results

Access-site complications occurred in 55 of 287 patients: 34 hematomas (11.9%), 20 pseudoaneurysms (7.0%), and 1 dissection (0.4%). In the crude model, risk factors related to access-site complications were the usage of 18-G needles (OR, 2.18; 95% CI, 1.17-4.07; P = 0.014), smoking (OR, 2.23; 95% CI, 1.16-4.27; P = 0.016), and approach route (OR, 3.23; 95% CI, 1.33-7.82; P = 0.009). Needle size (OR, 2.13; 95% CI, 1.10-4.12; P = 0.025) was the only factor associated with access-site complications in the adjusted model.

Conclusion

Needle profile was the only factor associated with access-site complications in this study. Therefore, a needle with a smaller profile than an 18-G needle will reduce the incidence of complications at the access site.

Clinical Implication of Candida Score in Multidrug-Resistant Pneumonia with Airway Candida Colonization

Background

The growth of Candida in respiratory secretions is usually considered colonization, and antifungal therapy is rarely required. The role of Candida colonization in the progression of bacterial pneumonia remains controversial. The aim of this study was to identify the clinical implication of Candida score by analyzinge the relationship with multidrug-resistant (MDR) pneumonia and prognosis in patients with airway Candida colonization.

Materials and Methods

This study was a retrospective review of patients with airway Candida colonization by bronchial washing or bronchoalveolar lavage. The Candida score was calculated according to the four factors (severe sepsis, surgery at baseline, total parenteral nutrition, and multifocal Candida colonization). Pneumonia related mortality or hopeless discharge expecting death was defined as a poor outcome.

Results

A total of 148 patients were enrolled in the study. In a multivariate analysis model, Candida score was identified as an independent predictor of poor outcomes (odds ratio 2.23; 95% confidential interval 1.57 – 3.17; P <0.001) in pneumonia patients with airway Candida colonization. With a Candida score of three or higher compared with low score group, it was associated with bacterial pneumonia, especially methicillin-resistant Staphylococcus aureus (MRSA) infection (0.0% vs. 15.2%, P = 0.004). In addition, patients with a high Candida score had a longer hospital stay (13 vs. 38 days, P <0.001), longer duration of intensive care (7 vs. 18 days, P <0.001), and higher pneumonia-related mortality (0.0% vs. 45.5%, P <0.001) as compared to the low Candida score group. The Candida score showed a positive correlation with other pneumonia severity scales such as CURB-65 (Confusion, Urea, Respiratory rate, Blood pressure, and age ≥65 years) (r = 0.461, P <0.001), Pneumonia Severity Index (r = 0.397, P <0.001), and predisposition, insult, response, and organ dysfunction (PIRO) score (r = 0.425, P <0.001).

Conclusion

This study revealed that Candida is no longer a bystander of airway colonization, and that it affects the progression of bacterial pneumonia, including multidrug-resistant pathogens, particularly MRSA infection. Also Candida score can be used to predict the prognosis of patients with pneumonia.

[Analysis of the pulmonary function characteristics and associated factors in silicosis patients with progressive massive fibrosis]

Objective: To investigate the characteristics of and associated risk factors for pulmonary dysfunction in silicosis patients with progressive massive fibrosis (PMF) . Methods: In-patients with PMF treated in the Department of Occupational Medicine and Toxicology in Beijing Chao-Yang Hospital, Capital Medical University from June 2014 to October 2020 were enrolled in this study. Based on their pulmonary ventilation function, the patients were divided into normal ventilation group, obstructive ventilation dysfunction group, restrictive ventilation dysfunction group, and mixed ventilation dysfunction group. The location and area of the large opacity and the grade of emphysema were evaluated by high-resolution CT (HRCT) of the chest. Based on the location, the large opacity was classified into central type, peripheral type, and mixed type. Results: A total of 115 silicosis patients with PMF were enrolled, with 85 (73.91%) having different types of pulmonary dysfunction, including 36 cases (31.30%) in the obstructive ventilation dysfunction group, 9 cases (7.83%) in the restrictive ventilation dysfunction group and 40 cases (34.78%) in the mixed ventilation dysfunction group. As for the location of the large opacity, 41 cases (35.65%) were central type, 52 cases (45.22%) were peripheral type, and 22 cases (19.13%) were mixed type. Logistic regression analysis showed that the central large opacity and grade 3-4 emphysema were risk factors for obstructive ventilation dysfunction (OR=52.179, 5.500, P<0.05) , class C large opacity was the risk factor for restrictive ventilation dysfunction (OR=33.146, P<0.05) , class B, class C large opacity and central large opacity were the risk factors for mixed ventilation dysfunction (OR=6.414, 11.561, 19.600, P<0.05) . Conclusion: In silicosis patients with PMF, the incidence rate of pulmonary ventilation dysfunction is higher, mainly obstructive and mixed ventilation dysfunction. The area and location of large opacity are associated with the incidence and types of pulmonary ventilation dysfunction.

Association of vancomycin trough concentration on the treatment outcome of patients with bacteremia caused by Enterococcus species

Background

Pharmacokinetic-pharmacodynamic (PK/PD) targets of vancomycin therapy have been recognized for methicillin-resistant Staphylococcus aureus infections but not for other gram-positive bacterial infections. Therefore, we investigated whether vancomycin concentration targets such as the trough level and ratio of the area under the curve to minimum inhibitory concentration (AUC/MIC) are associated with the treatment outcome in enterococcal bacteremia.

Methods

A retrospective cohort analysis enrolled patients with bacteremia caused by vancomycin-susceptible Enterococcus faecium and Enterococcus faecalis who were treated with vancomycin from January 2007 to December 2017 at a tertiary hospital located in Seoul, South Korea. Patients without vancomycin concentrations were excluded from the study. The primary outcome was 28-day all-cause mortality.

Results

A total of 37 patients were enrolled—26 with E. faecium infection and 11 with E. faecalis infection. The 28-day all-cause mortality rate was 21.6 %. In univariate analysis, vancomycin trough level (≤ 15 µg/mL; p = 0.042), age (p = 0.044), and septic shock (p = 0.049) were associated with 28-day mortality but not AUC24/MIC (> 389; p = 0.479). In multivariate analysis, vancomycin trough concentration (≤ 15 µg/mL; p = 0.041) and younger age (p = 0.031) were associated with 28-day mortality in patients with enterococcal bacteremia.

Conclusions

In this study, a vancomycin trough level of 15 µg/mL or lower was associated with 28-day mortality in enterococcal bacteremia. However, relatively large prospective studies are needed to examine the efficacy of vancomycin PK/PD parameters in patients with enterococcal bacteremia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06809-x.

[A case of oral hydrochloric acid poisoning treatment]

The case of oral hydrochloric acid poisoning is rare in clinic, and it is easy to be misdiagnosed when the poison is not clear. The clinical data of 1 case of oral hydrochloric acid poisoning successfully treated was retrospectively analyzed to provide reference for diagnosis and treatment of similar clinical cases.

[Analysis of related risk factors in the occurrence of mercury-toxic nephrotic syndrome]

Objective: To analyse the clinical characteristics of mercury-toxic nephrotic syndrome and to find the risk factors. Methods: A total of 126 patients with mercury-toxic admitted to Beijing Chaoyang Hospital from January 2017 to January 2020 were selected as the research objectives. General data such as age, gender, mercury exposure history of all patients and laboratory data such as urine mercury and urine creatinine were collected. The clinical manifestations and pathological types of patients with mercury-toxic nephrotic syndrome were analyzed, and the risk factors of mercury-toxic nephrotic syndrome were found by univariate and multivariate logistic regression analysis. Results: Among the 24 patients with mercury-toxic nephrotic syndrome, 1 was poisoned by respiratory tract, 6 were poisoned by digestive tract, and 17 were poisoned by skin absorption. In addition to the manifestations of kidney injury, some of the patients also showed neurological symptoms such as dizziness, fatigue, hand tremor, and limb pain. The main pathological types were membranous nephropathy (9 cases) and micropathological nephropathy (10 cases) . The results of multivariate logistic regression analysis showed that the digestive tract and skin absorption pathways of mercury were risk factors for mercury-toxic nephrotic syndrome (OR=21.099, 23.840, P<0.05) . Conclusion: The absorption pathway of mercury has an important influence on the pathogenesis of mercury-toxic nephrotic syndrome, especially in patients with mercury poisoning absorbed by the skin and digestive tract, the risk of complicating nephrotic syndrome is higher.

Effect of sex hormones on coronavirus disease 2019: an analysis of 5,061 laboratory-confirmed cases in South Korea

OBJECTIVE

To evaluate the effect of female sex hormones on the clinical outcomes of coronavirus disease 2019 patients using national claims data.

METHODS

This retrospective cohort study used the Health Insurance Review and Assessment data of 5,061 adult patients with laboratory-confirmed coronavirus disease 2019 in South Korea from January 20 to April 8, 2020. To evaluate the effect of hormone therapy on clinical outcomes among women, subgroup analyses using age-matched case-control data were performed.

RESULTS

Coronavirus disease 2019 was most prevalent in women in the 20-39 years age group (1,250 [44.14%]). Men were more likely to receive oxygen therapy (144 [6.46%] vs 131 [4.63%], P = 0.004), be admitted to the intensive care unit (60 [2.69%] vs 53 [1.87%], P = 0.049), and have a longer length of stay after admission to the intensive care unit (19.70 ± 11.80 vs 14.75 ± 9.23, P = 0.016). However, there was no significant difference in the mortality rate (men vs women: 42 [1.88%] vs 42 [1.48%], P = 0.267). In the multivariable Cox analysis, older age and underlying comorbidities, but not sex, were independent risk factors for mortality. Hormone therapy was not significantly associated with clinical outcomes.

CONCLUSIONS

This study, using nationwide data, suggests that female sex hormones are not associated with the morbidity and clinical outcomes of coronavirus disease 2019 in South Korea.

The clinical and economic burden of community-onset complicated skin and skin structure infections in Korea

BACKGROUND/AIMS

To investigate epidemiologic characteristics, clinical and economic burdens, and factors associated with mortality in complicated skin and skin structure infection (cSSSI) patients in Korea.

METHODS

A retrospective, observational, nationwide study was conducted between April to July 2012 at 14 tertiary-hospitals in Korea. Eligible patients were hospitalized adults with community acquired cSSSI, who underwent surgical intervention and completed treatment between November 2009 and October 2011. Data on demography, clinical characteristics, outcomes and medical resource utilization were collected through medical record review. Direct medical costs were calculated by multiplying quantities of resources utilized by each unit price in Korea.

RESULTS

Of 473 patients enrolled, 449 patients (except 24 patients with no record on surgical intervention) were eligible for analysis. Microbiological testing was performed on 66.1% of patients and 8.2% had multiple pathogens. Among culture confirmed pathogens (n = 297 patients, 340 episodes), 76.2% were gram-positive (Staphylococcus aureus; 41.2%) and 23.8% were gram-negative. The median duration of hospital stay was 16 days. Among treated patients, 3.3% experienced recurrence and 4.2% died in-hospital. The mean direct medical costs amounted to $4,195/ person, with the greatest expenses for hospitalization and antibiotics. The in-hospital mortality and total medical costs were higher in combined antibiotics therapy than monotherapy (p < 0.05). Charlson's comorbidity index ≥ 3, standardized early warning scoring ≥ 4, sub-fascia infections and combined initial therapy, were all found to be associated with higher mortality.

CONCLUSION

Korean patients with community-onset cSSSI suffer from considerable clinical and economic burden. Efforts should be made to reduce this burden through appropriate initial treatment.

Is Only Clarithromycin Susceptibility Important for the Successful Eradication of Helicobacter pylori?

Resistance to clarithromycin and other antibiotics included in the eradication regimen, such as amoxicillin and metronidazole, is important for Helicobacter pylori (H. pylori) eradication. The aim of this study was to investigate the correlation between the results of antimicrobial susceptibility testing and the eradication rate, as well as to understand the importance of antimicrobial susceptibility testing in H. pylori eradication. We retrospectively reviewed the electronic medical records of 1862 patients who underwent gastric biopsy for the culture of H. pylori during upper endoscopy from March 2015 to June 2019. We tried to find a correlation between the results of the antimicrobial susceptibility testing and the eradication rate in patients who received standard triple or concomitant therapy. A total of 247 patients exhibited positive results for culture and underwent antimicrobial susceptibility testing. Of these, 146 received eradication therapy, with follow-up tests after treatment. In the standard triple therapy, patients who were susceptible to both clarithromycin and amoxicillin exhibited significantly higher eradication rates (85.9%) than those susceptible to clarithromycin and resistant to amoxicillin (75.0%) or those resistant to clarithromycin and susceptible to amoxicillin (44.4%) (p = 0.013). In the concomitant therapy, patients who were susceptible to both clarithromycin and metronidazole had significantly higher eradication rates (96.3%) than those susceptible to clarithromycin and resistant to metronidazole (88.9%) or those resistant to clarithromycin and susceptible to metronidazole (50.0%) (p = 0.016). There was a correlation between the results of antimicrobial susceptibility testing and the eradication rate for H. pylori. In addition to clarithromycin, susceptibility to amoxicillin and metronidazole is also important for the successful eradication of H. pylori.

A Modified Simple Scoring System Using the Red Blood Cell Distribution Width, Delta Neutrophil Index, and Mean Platelet Volume-to-Platelet Count to Predict 28-Day Mortality in Patients With Sepsis

BACKGROUND

Recently, a new scoring system was developed that uses the red blood cell distribution width (RDW), delta neutrophil index (DNI), and platelet count (PC) to predict mortality in patients with sepsis. We investigated whether a modified simple scoring system based on the RDW, DNI, and mean platelet volume-to-PC (MPV/PC) ratio could predict the mortality of patients with sepsis, and compared it to the previous scoring system.

METHODS

We conducted a retrospective cohort study of 264 adults who had been treated for sepsis in an emergency department between January 2016 and February 2019. Each patient was rated on a scale of 0 to 3 according to the modified scoring system. Point values were assigned based on RDW > 14.5%, DNI > 5.0%, and MPV/PC ratio >10.1.

RESULTS

The 28-day mortality rate was 14.4%. Those who died had higher scores than those who survived (mean: 1.55 ± 0.92 vs 0.93 ± 0.78, P < .001). The area under the curve for the new scoring system was higher than that of the previous scoring system (0.685 vs 0.645).

CONCLUSION

The modified scoring system was a good predictor of the 28-day mortality and was more useful than the previous scoring system for predicting mortality in patients with sepsis.

A multicenter retrospective analysis of the antifungal susceptibility patterns of Candida species and the predictive factors of mortality in South Korean patients with candidemia

As detection rates of non-albicans Candida species are increasing, determining their pathogen profiles and antifungal susceptibilities is important for antifungal treatment selection. We identified the antifungal susceptibility patterns and predictive factors for mortality in candidemia.A multicenter retrospective analysis of patients with at least 1 blood culture positive for Candida species was conducted. Candida species were classified into 3 groups (group A, Candia albicans; group B, Candida tropicalis, and Candida parasilosis; group C, Candida glabrata and Candida krusei ) to analyze the susceptibility patterns, first-line antifungal administered, and mortality. Univariate and multivariate comparisons between outcomes were performed to identify mortality risk factors.In total, 317 patients were identified, and 136 (42.9%) had recorded mortality. Echinocandin susceptibility was higher for group A than group B (111/111 [100%] vs 77/94 [81.9%], P < .001). Moreover, group A demonstrated higher fluconazole susceptibility (144/149 [96.6%] vs 39/55 [70.9%], P < .001) and lower mortality (68 [45.3%] vs 34 [61.8%], P = .036) than those of group C. In the multivariate analysis, the sequential organ failure assessment score (odds ratio OR 1.351, 95% confidence interval 1.067-1.711, p = 0.013) and positive blood culture on day 7 of hospitalization (odds ratio 5.506, 95% confidence interval, 1.697-17.860, P = .004) were associated with a higher risk of mortality.Patients with higher sequential organ failure assessment scores and sustained positive blood cultures have an increased risk of mortality.

Prognostic factors for unfavourable outcomes of patients with spinal tuberculosis in a country with an intermediate tuberculosis burden

Aims

Spinal tuberculosis (TB) remains an important concern. Although spinal TB often has sequelae such as myelopathy after treatment, the predictive factors affecting such unfavourable outcomes are not yet established. We investigated the clinical manifestations and predictors of unfavourable treatment outcomes in patients with spinal TB.

Patients and Methods

We performed a multicentre retrospective cohort study of patients with spinal TB. Unfavourable outcome was defined according to previous studies. The prognostic factors for unfavourable outcomes as the primary outcome were determined using multivariable logistic regression analysis and a linear mixed model was used to compare time course of inflammatory markers during treatment. A total of 185 patients were included, of whom 59 patients had unfavourable outcomes.

Results

In multivariate regression analysis, the factors associated with unfavourable outcome were old age (odds ratio (OR) 2.51; 95% confidence interval (CI) 1.07 to 5.86; p = 0.034), acid-fast bacilli (AFB) smear positivity in specimens obtained through biopsy (OR 3.05; 95% CI 1.06 to 8.80; p = 0.039), and elevated erythrocyte sedimentation rate (ESR) at the end of treatment (OR 3.85; 95% CI 1.62 to 9.13; p = 0.002). Patients with unfavourable outcomes had a significant trend toward higher ESR during treatment compared with patients with favourable outcome (p = 0.009). Duration of anti-TB and surgical treatment did not affect prognosis.

Conclusion

Elevated ESR at the end of treatment could be used as a marker to identify spinal TB patients with a poor prognosis. Patients whose ESR is not normalized during treatment, as well as those with old age and AFB smear positivity, should be aware of unfavourable outcomes. Cite this article: Bone Joint J 2019;101-B:1542–1549

In vivo efficacy of combination of colistin with fosfomycin or minocycline in a mouse model of multidrug-resistant Acinetobacter baumannii pneumonia

Unfortunately, the options for treating multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) infections are extremely limited. Recently, fosfomycin and minocycline were newly introduced as a treatment option for MDR A. baumannii infection. Therefore, we investigated the efficacy of the combination of colistin with fosfomycin and minocycline, respectively, as therapeutic options in MDR A. baumannii pneumonia. We examined a carbapenem-resistant A. baumannii isolated from clinical specimens at Severance Hospital, Seoul, Korea. The effect of colistin with fosfomycin, and colistin with minocycline on the bacterial counts in lung tissue was investigated in a mouse model of pneumonia caused by MDR A. baumannii. In vivo, colistin with fosfomycin or minocycline significantly (p < 0.05) reduced the bacterial load in the lungs compared with the controls at 24 and 48 h. In the combination groups, the bacterial loads differed significantly (p < 0.05) from that with the more active antimicrobial alone. Moreover, the combination regimens of colistin with fosfomycin and colistin with minocycline showed bactericidal and synergistic effects compared with the more active antimicrobial alone at 24 and 48 h. This study demonstrated the synergistic effects of combination regimens of colistin with fosfomycin and minocycline, respectively, as therapeutic options in pneumonia caused by MDR A. baumannii.

2306. Impact of Cytomegalovirus Disease on New-Onset Dementia: Population-Based-Matched Case–Control Cohort Study

Background

The association of human cytomegalovirus (CMV) with dementia is still controversial. Previous studies suggested that serostatus of latent CMV infection assessed by serum CMV IgG could play a role in development of neurodegeneration with cognitive impairment. This study is aimed to evaluate the relation of CMV tissue invasive diseases to vascular dementia and Alzheimer’s dementia.

Methods

The ICD-10 codes from the National Health Insurance Database covering 50 million people were used to collect the patient group (n = 687) aged ≥ 40 years with CMV tissue invasive end-organ diseases and control group (n = 3,435) matched by non-CMV infection, age and sex with 1:5 ratio. The subjects were retrieved for enrolled patients during 2010–2014 with wash-out period for 6 years, and followed until December 2016.

Results

Multivariate regression model adjusted by age and sex showed a significantly higher incidence rate of dementia (odds ratio [OR], 2.10 and 95% confidence intervals [CI], 1.45–3.05) in patients with CMV disease. According to the type of dementia, the risk of vascular dementia in patient group (OR, 3.31 and 95% CI, 1.30–8.41) was higher than Alzheimer’s dementia (OR, 1.74 and 95% CI, 1.09–2.78). In the age subgroup analysis adjusted by sex, patients aged 40–59 years with CMV disease had a higher risk of dementia than those aged ≥ 60 years (OR, 12.3 [95% CI, 3.2–47.6] vs. 1.8 [95% CI, 1.2–2.7], P = 0.010).

Conclusion

CMV disease independently increased the risk of vascular dementia as well as Alzheimer’s dementia.

Disclosures

All authors: No reported disclosures.

146. Infective Endocarditis in South Korea: a 12-year Single-Center Experience of 419 Patients

Background

Infective endocarditis (IE) is a potentially lethal disease that has undergone constant changes in epidemiology and pathogen. Treatment of IE has become more complex with today’s myriad healthcare-associated factors as well as regional differences in causative organisms. Therefore, it is necessary to investigate the overall trends, microbiological features, clinical characteristics and outcomes of IE in South Korea.

Methods

We performed a retrospective cohort study of patients with the diagnosis of probable or definite IE according to the modified Duke Criteria admitted to a tertiary care center in South Korea between November 2005 and August 2017. Poisson log-linear regression was used to estimate time trends of IE incidence rate and mortality rate. Risk factors for in-hospital mortality were evaluated by multivariate logistic regression analysis including an interaction term.

Results

There were 419 IE patients (275 male vs. 144 female) during the study period. The median age of the patients was 56 years. The annual incidence rate of IE of our institution was significantly increased. (RR 1.05; 95% CI, 1.02–1.08; P = 0.006) The mortality rate showed trends toward down, but not statistically significant (P = 0.875). IE was related to a prosthetic valve in 15.0% and 21.7% patients developed IE during hospitalization. The mitral valve was the most commonly affected valve (61.3%). Causative microorganisms were identified in 309 patients (73.7%) and included streptococci (34.6%), followed by Staphylococcus aureus (15.8%) and enterococci (7.9%). The in-hospital mortality rate was 14.6%. Logistic regression analysis found aortic valve endocarditis (OR 3.18; P = 0.001), IE caused by staphylococcus aureus (OR 2.32; P = 0.026), a presence of central nervous system embolic complication (OR 1.98; P = 0.031), a high SOFA score (OR 1.22; P = 0.023) and a high Charlson’s comorbidity index (OR 1.11; P = 0.019) as predictors of in-hospital mortality. On the other hand, surgical intervention for IE was found to be a protective factor against mortality. (OR 0.25, P < 0.001)

Conclusion

Although IE has been increasing, the mortality rate has not yet reduced significantly. Studies on causative organisms of IE and risk factors for mortality are warranted in improving prognosis.

Disclosures

All authors: No reported disclosures.

1365. Profiling Extrapulmonary Nontuberculous Mycobacteria Infections and Predictors for rapid-growing Species: A Multi-Center Retrospective Study

Background

Nontuberculous mycobacteria (NTM) disease is increasing worldwide and is an important cause of morbidity and mortality. It is found that 20 to 30% of NTM isolates are of extrapulmonary origin. However, Studies about extrapulmonary NTM infections have been limited. Thus, we aim to describe the diversity of NTM infections and correlate these observations with clinical data.

Methods

We analyzed all symptomatic patients with positive NTM cultures in sterile extrapulmonary sites at three tertiary care centers in South Korea between January 2006 and June 2018. We collected patient information including predisposing factors, diversity of NTM isolates, antimicrobial susceptibility testing, treatment regimens, and outcomes.

Results

A total of 117 patients (46 males vs. 71 females) were included. The median age of the patients was 54 years. There are a lot of infections associated with medical procedures like surgery, but about half of cases (54.7%) are unknown origin. Skin and soft-tissue infections predominated (34.2%), followed by bone and joint infections (28.2%). Of 117 NTM isolates, 66 NTM subspecies were identified. Mycobacterium intracellulare (34.8%) was the most common species identified, followed rapid-growing NTM (RGM) species such as M. fortuitum complex (21.2%), M. abscessus (15.2%), M. massiliense (10.6%), and M. chelonae (9.1%). In skin and soft-tissue infections, RGM species were predominantly identified (26/28, 92.9%), whereas slow-growing NTM (SGM) species were mainly identified in bone and joint infections (18/26, 69.2%). The difference of isolated sites was verified by post hoc test and female sex (OR 4.72; P < 0.001) and skin and soft-tissue infections (OR 25.33; P < 0.001) were identified as predictors of RGM by logistic regression analysis. Based on antimicrobial susceptibility testing, fluoroquinolone and macrolide were mainly used for RGM treatment, and rifamycin-ethambutol-macrolide-based regimen was predominantly used for SGM treatment.

Conclusion

Skin and soft-tissue infection were predominantly caused by RGM, whereas bone and joint infection is mainly caused by SGM. Species-specific and region-specific data that integrate clinical and microbiologic information is crucial in determining treatment direction.

Disclosures

All authors: No reported disclosures.

1366. Prognostic Factors for Unfavorable Outcomes of Patients with Spinal Tuberculosis in a Country with an Intermediate Tuberculosis Burden: a Multi-Center Cohort Study

Background

Spinal tuberculosis (TB) remains an important concern. Although spinal TB often has sequelae such as myelopathy after treatment, the predictive factors affecting such unfavorable outcomes are not yet known. Therefore, we investigated the clinical manifestations and predictors of unfavorable treatment outcomes in patients with spinal TB.

Methods

We performed a multi-center retrospective cohort study of patients with spinal TB. The clinical features, comorbidities, laboratory data, imaging findings and treatment outcomes of the patients were analyzed. The unfavorable outcome was defined according to previous studies. The prognostic factors for unfavorable outcomes as the primary outcome were determined using multivariate logistic regression analysis and a linear mixed model were used to compare time course of inflammatory markers during treatment.

Results

A total of 185 patients (85 males and 100 females) were included. The mean age of the patients was 57.2 years. Of them, 115 underwent surgery during treatment, with a median treatment duration of 12 months. Fifty-nine patients had unfavorable outcomes. In multivariate regression analysis, the factors associated with unfavorable outcome were old age (odds ratio [OR], 2.51; P = 0.034), acid-fast bacilli (AFB) smear positivity in specimens obtained through biopsy (OR, 3.05; P = 0.039), and elevated erythrocyte sedimentation rate (ESR) at the end of treatment (OR, 3.85; P = 0.002). Patients with unfavorable outcomes had a significant trend toward higher ESR during treatment compared with patients with favorable outcome (P = 0.009). Duration of anti-TB and surgical treatment did not affect prognosis.

Conclusion

Elevated ESR at the end of treatment could be used as a marker to identify spinal TB patients with a poor prognosis. Patients whose ESR are not normalized during treatment, as well as those with old age and AFB smear positivity, should be aware of unfavorable outcomes.

Disclosures

All authors: No reported disclosures.

Early Detection of Bacteraemia Using Ten Clinical Variables with an Artificial Neural Network Approach

An adequate model for predicting bacteraemia has not yet been developed. This study aimed to evaluate the performance of an artificial neural network (ANN)-based prediction model in comparison with previous statistical models. The performance of multi-layer perceptron (MLP), a representative ANN model, was verified via comparison with a non-neural network model. A total of 1260 bacteraemia episodes were identified in 13,402 patients. In MLP with 128 hidden layer nodes, the area under the receiver operating characteristic curve (AUC) of the prediction performance was 0.729 (95% confidence interval [CI]; 0.712–0.728), while in MLP with 256 hidden layer nodes, it was 0.727 (95% CI; 0.713–0.727). In a conventional Bayesian statistical method, the AUC was 0.7. The aforementioned two MLP models exhibited the highest sensitivity (0.810). The ranking of clinical variables was used to describe the influential power of the prediction. Serum alkaline phosphatase was one of the most influential clinical variables, and one-out search was the best ranking method for measuring the influence of the clinical variables. Furthermore, adding variables beyond the 10 top-ranking ones did not significantly affect the prediction of bacteraemia. The ANN model is not inferior to conventional statistical approaches. Bacteraemia can be predicted using only the top 10 clinical variables determined by a ranking method, and the model can be used in clinical practice by applying real-time monitoring.

Risk factors for mortality in patients with Stenotrophomonas maltophilia bacteremia and clinical impact of quinolone-resistant strains

Background

Stenotrophomonas maltophilia is an important nosocomial pathogen. This pathogen has intrinsic or acquired resistance to a number of antibiotics classes. Furthermore, Stenotrophomonas infections have been associated with high mortality, mainly in immunocompromised patients. Accordingly, we conducted a retrospective cohort study on the clinical data, microbiological characteristics, and outcomes of patients with S. maltophilia (SM) bacteremia.

Methods

A retrospective cohort study was conducted at two tertiary care referral hospitals in Seoul, South Korea. Data were collected between January 2006 and December 2015 from electric medical records. Our analysis aimed to identify the risk factors associated with crude mortality, as well as the predictive factors of quinolone-resistant strains in SM bacteremia patients.

Results

A total of 126 bacteremia patients were enrolled in the study. The mortality rate was 65.1%. On multivariable analysis, hypoalbuminemia (odds ratio [OR], 5.090; 95% confidence interval [CI], 1.321–19.621; P = 0.018), hematologic malignancy (OR, 35.567; 95% CI, 2.517–502.515; P = 0.008) and quinolone-resistant strains (OR, 7.785; 95% CI, 1.278–47.432; P = 0.026) were independent risk factors for mortality. Alternatively, usage of an empirical regimen with quinolone (OR, 0.172; 95% CI, 0.034–0.875; P = 0.034) was an independent protective factor for mortality. The multivariable analysis of predictive factors revealed that high Charlson comorbidity index (OR, 1.190; 95% CI, 1.040–1.361; P = 0.011) and indwelling of a central venous catheter (CVC) (OR, 3.303; 95% CI, 1.194–9.139; P = 0.021) were independent predisposing factors associated with quinolone-resistant strains in SM bacteremia patients.

Conclusions

Our findings suggest that a high Charlson comorbidity score and indwelling of a CVC were significantly independent predictors of quinolone-resistant strains in SM bacteremia patients. Therefore, we need to carefully consider the antibiotic use in SM bacteremia patients with these predictive factors.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4394-4) contains supplementary material, which is available to authorized users.

[Clinical characteristics, treatment and outcome of chronic mercury-related nephrotic syndrome]

Objective: To investigate the etiology, clinical features, treatment and outcome of nephrotic syndrome associated with chronic mercury poisoning. Methods: From June 2013 to April 2018, Beijing Chaoyang Hospital, Capital Medical University received 33 patients with chronic mercury-neutral nephrotic syndrome. The clinical manifestations, laboratory tests, treatment methods, and outcomes were analyzed. Results: Among the 33 patients, 27 patients had mercury exposure due to daily-life contact and the other 6 patients were caused by iatrogenic mercury. The symptom was characterized by typical nephrotic syndrome such as lower extremity edema and proteinuria at first onset. The treatment was based on mercury-removing treatment, 19 cases were treated with mercury removal alone, 16 cases were completely relieved; 10 cases were treated with mercury removal and glucocorticoids, all of which were completely relieved; 4 cases were treated with mercury removal, glucocorticoids and immunosuppressive agents, all complete remission; clinical complete remission rate is about 90.9% (30 cases in total) . Urinary mercury levels decreased the fastest between the first and second courses of mercury treatment, but the total amount of urine protein increased. As the amount of urinary mercury excreted increased, the total amount of urine protein decreased gradually (Z=2.86, P<0.01) . Conclusion: The clinical features of chronic mercury-induced nephrotic syndrome are non-specific, easy to be misdiagnosed and missed. The treatment is mainly treated with mercury removal treatment. The prognosis is good. In severe cases, glucocorticoid therapy can be supplemented.

The incidence and risk factors for surgical site infection in older adults after gastric cancer surgery: A STROBE-compliant retrospective study

Surgical site infection (SSI) is a well-known complication in older adults. However, there have been no studies on SSI after gastrectomy in older adults. Therefore, we aimed to investigate the incidence, risk factors, and outcomes of SSIs after gastrectomy in older adults.We performed a retrospective cohort study of older adults, aged 65 years or older, who underwent gastrectomy between January 2015 and December 2015 at the Severance Hospital in Seoul, Korea. The incidence and outcomes of SSIs after gastrectomy were evaluated, and the risk factors for SSI were identified using multivariate analyses.We identified 353 older adults who underwent gastrectomy. Of these, 25 patients (7.1%) developed an SSI. Multivariate analysis indicated that open surgery (odds ratio, 2.71; 95% confidence interval, 1.13-6.51; P = .03) and a longer operation time (odds ratio, 1.01; 95% confidence interval, 1.00-1.01; P = .04) were independent risk factors for SSI after gastrectomy. In the SSI group, the incidence of postoperative fever (84.0% vs 51.8%; P < .001), length of postoperative hospital stay (13 days vs 6 days; P < .001), and re-admission rates within 30 days postoperatively (32.0% vs 3.4%; P < .001) were significantly higher than those in the non-SSI group.The risk factors for SSI in older adults after gastrectomy were open surgery and a longer operation time. When an SSI occurred, the postoperative hospital stay was prolonged and the chances of having a postoperative fever and being re-admitted within 30 days increased.

Gentamicin-intercalated smectite as a new therapeutic option for Helicobacter pylori eradication

Objectives

Novel antibacterial strategies against Helicobacter pylori are needed because H. pylori strains are acquiring resistance to antibiotics. We evaluated the efficacy of gentamicin-intercalated smectite hybrid (S-GEN)-based treatment regimens in a murine model of H. pylori infection.

Methods

Two groups of 10 rats were administered either smectite or S-GEN to measure coverage of the gastric mucosa. To evaluate anti-H. pylori efficacy, mice were divided into eight groups of 10 mice each given different treatments, and H. pylori eradication was assessed by a Campylobacter-like organism (CLO) test and H. pylori PCR of the gastric mucosa, and H. pylori antigen and H. pylori PCR analysis of mouse faeces. The levels of proinflammatory cytokines were examined.

Results

S-GEN was retained in the gastric mucosal layer with a >60% distribution ratio for up to 1 h, and the S-GEN-based triple regimen decreased bacterial burden in vivo compared with that of untreated mice or mice treated with other regimens. The cure rates in the CLO test and H. pylori PCR from gastric mucosa were 70%, 60%, 80%, 50%, 60% and 60% in Groups III-VIII, respectively. Those for H. pylori PCR in the faeces of mice were 90% and 100% in Group III with standard therapy and Group V with triple therapy including S-GEN, respectively. S-GEN triple therapy also reduced the levels of proinflammatory cytokines.

Conclusions

These results suggest that S-GEN is a promising and effective therapeutic agent for the treatment of H. pylori infection.