Description of an anaerobic actinobacterium, Kribbibacterium absianum gen. nov., sp. nov., a new member of the novel family Kribbibacteriaceae fam. nov., and reclassification of the genera Granulimonas and Leptogranulimonas

Two rod-shaped, obligate anaerobic, Gram-stain-positive bacteria isolated from the pig faeces were designated YH-ols2216 and YH-ols2217T. Analysis of 16S rRNA gene sequences revealed that these isolates were most related to the members of the family Atopobiaceae, within the order Coriobacteriales, and Granulimonas faecalis KCTC 25474T with 92.0 and 92.5% similarities, respectively. The 16S rRNA gene sequence similarity within isolates was 99.9 %; and those between isolates YH-ols2216 and YH-ols2217T, and Atopobium minutum DSM 20586T, the type species of the type genus Atopobium within the family Atopobiaceae, were 88.5 and 88.7 %, respectively. Those between isolates and Coriobacterium glomerans PW2T, the type species of the type genus Coriobacterium within the family Coriobacteriaceae, were 88.7 and 89.1 %, respectively. The multi-locus sequence tree revealed that the isolates, alongside the genera Granulimonas and Leptogranulimonas, formed a distinct cluster between the families Atopobiaceae and Coriobacteriaceae. The average nucleotide identities and digital DNA-DNA hybridization values for the isolates and their most closely related strains ranged from 67.7 to 76.2 % and from 18.4 to 23.3 %, respectively. The main cellular fatty acids of the isolates were C18 : 0 DMA, C18 : 1  ω9c, C18 : 0 12OH, C18 : 0, and C16 : 0. The cell wall contained the peptidoglycan meso-diaminopimelic acid. Lactate was the main end-product of the isolates. The major polar lipids of isolate YH-ols2217T were aminophospholipid, aminolipids, and lipids. Menaquinones were not identified in the cells of the isolates. The DNA G+C contents of isolates YH-ols2216 and YH-ols2217T were 67.5 and 67.6 mol%, respectively. Considering these chemotaxonomic, phenotypic, and phylogenetic properties, Kribbibacteriaceae fam. nov. is proposed within the order Coriobacteriales. YH-ols2216 (=KCTC 25708=NBRC 116429) and YH-ols2217T (=KCTC 25709T=NBRC 116430T) represent a novel taxon within this new family and the name Kribbibacterium absianum gen. nov., sp. nov. is proposed. In addition, the genera Granulimonas and Leptogranulimonas are transferred to the family Kribbibacteriaceae fam. nov.

Aerococcus kribbianus sp. nov., a facultatively anaerobic bacterium isolated from pig faeces

Two cocci-shaped, facultatively anaerobic, Gram-positive bacteria isolated from the faeces of a pig were designated as strains YH-aer221T and YH-aer222. Analysis of the 16S rRNA gene sequences revealed that the isolates were most closely related to Aerococcus suis JCM 18035T with 96.6 % similarity. The multi-locus sequence tree revealed that the isolates formed a sub-cluster adjacent to A. suis JCM 18035T. The average nucleotide identity values for the isolates and their most closely related strains were 71.8 and 71.7 %, respectively; and the digital DNA-DNA hybridization values for the isolates and their most closely related strains were 25.6 and 25.5 %, respectively. The main fatty acids were C18 : 1ω9c, C16 : 0 and C18 : 0. The cell wall contained the meso-diaminopimelic acid-based peptidoglycan. The two isolates shared the same metabolic pathways. Isolates YH-aer221T and YH-aer222 harboured the same CRISPR array with 33 and 46 spacers, respectively. Single-genome vs. metagenome analysis showed that the genomes of the isolates were not found in the available metagenome database. Given their chemotaxonomic, phenotypic and phylogenetic properties, YH-aer221T (= KCTC 25571T=JCM 35699T) and YH-aer222 (=KCTC 25573=JCM 35700) represent a novel taxon. The name Aerococcus kribbianus sp. nov. is proposed.

Clinical usefulness of anaerobic blood culture in pediatric patients with bacteremia

OBJECTIVES

The purpose of this study is to evaluate the usefulness of anaerobic blood culture in pediatric patients by comparing the detection rate and distribution of bacteria between aerobic and anaerobic blood culture bottles.

METHODS

A retrospective analysis was conducted on 11,664 blood cultures obtained from children under the age of 14 between January 2013 and June 2020. The positive rate of total, aerobic, and anaerobic blood culture, as well as the species distribution of each blood culture bottle, were investigated.

RESULTS

The positive rate of blood culture was 2.4 % (N = 281). Among them, 67 (23.8 %), 85 (30.3 %) and 129 (45.9 %) organisms were grown in only aerobic, only anaerobic, and both blood culture bottles, respectively. Gram-positive cocci were cultured on both, only aerobic, and only anaerobic blood culture bottles in proportions of 46.4 %, 23.4 %, and 30.2 %, respectively. Gram-negative bacilli were cultured on both, only aerobic, and only anaerobic blood culture bottles in proportions of 58.5 %, 12,3 %, and 29.2 %, respectively. Gram-positive bacilli grew best in aerobic bottle only. There were seven strains of obligate anaerobes.

CONCLUSION

Because many facultative anaerobic bacteria are recognized primarily from anaerobic blood culture bottles, combining aerobic and anaerobic blood culture bottles might be beneficial in pediatric patients with suspected blood stream infection.

Description of Fusibacillus kribbianus gen. nov., sp. nov., a fusiform anaerobe isolated from pig feces

OBJECTIVE

The family Lachnospiraceae is affiliated with the order Clostridiales and was originally contained within Clostridial cluster XIVa. The members of Lachnospiraceae inhabiting the gut comprise the chemoorganotrophic genera, generating sundry short-chain fatty acids to supply energy to the host, and are considered to be related to obesity and gut health.

METHODS

The polyphasic taxonomic approach was used to characterize the isolate YH-rum2234T. A detailed metabolic analysis was conducted to compare the novel isolate with related strains within the family Lachnospiraceae.

RESULTS

A fusiform, obligately anaerobic, Gram-stain-negative bacterium, YH-rum2234T, was isolated from pig feces. Analysis of the 16S rRNA gene sequence revealed that the similarities between the isolate and the familiarly interrelated strain Lientehia hominis KCTC 25345T was 94.3%. The average nucleotide identities and genome-to-genome distances of YH-rum2234T and its closely related strains were below 85.5% and 32.5%, respectively. The G + C content of the genomic DNA was 49.2 mol%. The main fatty acids were C16:0, C14:0, and C14:0 DMA. The major polar lipids were aminophospholipids. The cell wall did not contain the peptidoglycan meso-diaminopimelic acid.

CONCLUSION

Given the chemotaxonomic, phenotypic, and phylogenetic properties, YH-rum2234T (=KCTC 25710T = DSMZ 116041T) represents a new genus and species in the family Lachnospiraceae. Fusibacillus kribbianus gen. nov., sp. nov. is the proposed name.

Navigating the microbial community in the trachea-oropharynx of breast cancer patients with or without neoadjuvant chemotherapy (NAC) via endotracheal tube: has NAC caused any change?

Background

We compare the diversity and niche specificity of the microbiome in the trachea-oropharynx microbiome of malignant breast neoplasm with or without neoadjuvant chemotherapy (NAC) via NGS analysis.

Methods

We prospectively collected a total of 40 endotracheal tubes intubated from subjects, of whom 20 with NAC treated breast cancer (NAC group) and 20 with breast cancer without NAC (Non-NAC group). We generated 16S rRNA-based microbial profiles in IlluminaTM platform and alpha diversity indices were compared between groups. For the comparison of taxa abundance, linear discriminant analysis effect size method with Kruskal-Wallis test was used. The distribution of variables between the two groups was compared using the Mann-Whitney test. For beta diversity analysis, PERMANOVA was used.

Results

Among the diversity indices, the NAC group showed significantly lower Chao1, Inverse Simpson, and Shannon indices than the Non-NAC group. The three most frequent taxa of all two groups were Streptococcus (20.4%), followed by Veillonella (11.9%), and Prevorella (10.4%). This order was the same in NAC and non-NAC groups.

Conclusion

Here, we provide the first comparison data of the respiratory tract microbiome of breast cancer patients with or without NAC via NGS analysis. This study ultimately seeks to contribute to future studies on the lower respiratory tract in cancer patients with cytotoxic chemotherapy by establishing reliable control data.

The novel immunobiotic Clostridium butyricum S-45-5 displays broad-spectrum antiviral activity in vitro and in vivo by inducing immune modulation

Clostridium butyricum is known as a probiotic butyric acid bacterium that can improve the intestinal environment. In this study, we isolated a new strain of C. butyricum from infant feces and evaluated its physiological characteristics and antiviral efficacy by modulating the innate immune responses in vitro and in vivo. The isolated C. butyricum S-45-5 showed typical characteristics of C. butyricum including bile acid resistance, antibacterial ability, and growth promotion of various lactic acid bacteria. As an antiviral effect, C. butyricum S-45-5 markedly reduced the replication of influenza A virus (PR8), Newcastle Disease Virus (NDV), and Herpes Simplex Virus (HSV) in RAW264.7 cells in vitro. This suppression can be explained by the induction of antiviral state in cells by the induction of antiviral, IFN-related genes and secretion of IFNs and pro-inflammatory cytokines. In vivo, oral administration of C. butyricum S-45-5 exhibited prophylactic effects on BALB/c mice against fatal doses of highly pathogenic mouse-adapted influenza A subtypes (H1N1, H3N2, and H9N2). Before challenge with influenza virus, C. butyricum S-45-5-treated BALB/c mice showed increased levels of IFN-β, IFN-γ, IL-6, and IL-12 in serum, the small intestine, and bronchoalveolar lavage fluid (BALF), which correlated with observed prophylactic effects. Interestingly, after challenge with influenza virus, C. butyricum S-45-5-treated BALB/c mice showed reduced levels of pro-inflammatory cytokines and relatively higher levels of anti-inflammatory cytokines at day 7 post-infection. Taken together, these findings suggest that C. butyricum S-45-5 plays an antiviral role in vitro and in vivo by inducing an antiviral state and affects immune modulation to alleviate local and systemic inflammatory responses caused by influenza virus infection. Our study provides the beneficial effects of the new C. butyricum S-45-5 with antiviral effects as a probiotic.

Limosilactobacillus kribbianus sp. nov., isolated from pig faeces

A rod-shaped, aerotolerant, Gram-stain-positive bacterium isolated from pig faeces was designated as strain YH-lim2214T. Analysis of the 16S rRNA gene sequence revealed that the isolate was most closely related to Limosilactobacillus pontis KCTC 25258T with 98.0 % similarity. The average nucleotide identity and average amino acid identity values between YH-lim2214T and the most closely related strain Lm. pontis KCTC 25258T were 81.4 and 81.3 %, respectively. The major fatty acids were C18 : 1  ω9c, summed feature 7 and C16 : 0. The cell-wall peptidoglycan type was A4α l-Lys-d-Asp. The genomic DNA G+C content was 51.1 mol%. The chemotaxonomic, phenotypic and phylogenetic properties of YH-lim2214T (=KCTC 25572T=JCM 35701T) suggest that it represents a novel taxon, for which the name Limosilactobacillus kribbianus sp. nov. is proposed.

Description and comparative genome analysis of Hallella absiana sp. nov., isolated from pig feces

OBJECTIVE

The genus Hallella was described within Bacteroidaceae, and then reclassified within Prevotellaceae based on its phenotypic and phylogenetic description. It is associated with degradation of carbohydrate. However, some species of Hallella have pathobiotic properties, and are involved in infections and chronic inflammatory disorders.

METHODS

Here, we used a polyphasic taxonomic approach to characterize the two strains: YH-C38^T and YH-C4B9b. A detailed metabolic analysis was conducted to compare the two novel isolates with related strains within the genus Hallella.

RESULT

Analysis of 16S rRNA gene sequences revealed that the isolates were most closely related to Hallella mizrahii JCM 34422^T with 98.5% and 98.6% similarities, respectively. Analysis of the multi-locus species tree based on whole genome sequences of the isolates and related strains revealed that the isolates formed a sub-cluster adjacent to H. mizrahii JCM 34422^T. The average nucleotide identity values for YH-C38^T and YH-C4B9b, and the most closely related strain H. mizrahii JCM 34422^T, were 93.5% and 93.8%, respectively. The main fatty acids were iso C_17:0 3OH and anteiso C_15:0. The predominant menaquinones were MK-12, MK-11, and MK-13. The cell wall contained the peptidoglycan of meso-diaminopimelic acid. Analysis of comparative metabolic analysis revealed that isolates YH-C38^T and YH-C4B9b each contained 155 carbohydrate-active enzymes, and glycoside hydrolase was the largest family.

CONCLUSION

Two rod-shaped, obligately anaerobic, Gram-stain-negative bacteria, isolated from pig feces, were designated as strains YH-C38^T and YH-C4B9b. Based on the chemotaxonomic, phenotypic, and phylogenetic properties, YH-C38^T (=KCTC 25103^T = JCM 35423^T) and YH-C4B9b (=KCTC 25104 = JCM 35609) represent a novel taxon. The name Hallella absiana sp. nov. is proposed.

Lacticaseibacillus parakribbianus sp. nov., isolated from a pig farm faeces dump

A lactic acid bacterium isolated from pig faeces was characterized using a polyphasic approach. The strain was Gram-stain-positive, rod-shaped, and facultative anaerobic. Phylogenetic analysis of the 16S rRNA gene sequence indicated that the isolate belonged to the genus Lacticaseibacillus. The multi-locus sequence tree revealed that the strain formed a sub-cluster adjacent to Lacticaseibacillus kribbianus. The main fatty acids were C_16 : 0 and C_18 : 1ω9c. The average nucleotide identity value, average amino acid identity, and genome-to-genome distance for YH-lacS6^T and its most closely related strain, L. kribbianus, were 85.4, 85.2 and 29.2 %, respectively. The G+C content of the genomic DNA was 61.6 mol%. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, aminophospholipids and phospholipids. The cell-wall peptidoglycan did not contain meso-diaminopimelic acid. Thus, YH-lacS6^T (=KCTC 21186^T=JCM 34954^T) represents a novel species. The name Lacticaseibacillus parakribbianus sp. nov. is proposed.

Emergence of NDM-1-producing Pseudomonas aeruginosa Sequence Type 773 Clone: Shift of Carbapenemase Molecular Epidemiology and Spread of 16S rRNA Methylase Genes in Korea

Imipenemase (IMP)-6-producing Pseudomonas aeruginosa sequence type (ST) 235 is a dominant clone of carbapenemase-producing P. aeruginosa (CPPAE) in Korea. As part of the Antimicrobial Resistance Surveillance System in Korea, we found an increase in the carbapenem resistance rate of P. aeruginosa isolates from blood cultures and a shift in the molecular epidemiology of CPPAE. A total of 212 non-duplicated P. aeruginosa blood isolates were obtained from nine general hospitals and two nursing homes. Twenty-four isolates were identified as CPPAE. We observed the emergence of the NDM-1 P. aeruginosa ST 773 clone (N=10), mostly from Gyeongsang Province. The IMP-6 ST 235 clone (N=11) was detected in all provinces. CPPAE isolates showed very high resistance rates to amikacin, and all NDM-1 P. aeruginosa strains carried rmtB. This is the first nationwide surveillance of the recently emerged NDM-1-producing P. aeruginosa ST773 clone in Korea. Continuous surveillance is necessary to prevent the infection and transmission of carbapenem- and amikacin-resistant P. aeruginosa in Korea.

Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Causing Invasive Pneumococcal Disease in Korea Between 2017 and 2019 After Introduction of the 13-Valent Pneumococcal Conjugate Vaccine

Background

Streptococcus pneumoniae is a serious pathogen causing various infections in humans. We evaluated the serotype distribution and antimicrobial resistance of S. pneumoniae causing invasive pneumococcal disease (IPD) after introduction of pneumococcal conjugate vaccine (PCV)13 in Korea and investigated the epidemiological characteristics of multidrug-resistant (MDR) isolates.

Methods

S. pneumoniae isolates causing IPD were collected from 16 hospitals in Korea between 2017 and 2019. Serotyping was performed using modified sequential multiplex PCR and the Quellung reaction. Antimicrobial susceptibility tests were performed using the broth microdilution method. Multilocus sequence typing was performed on MDR isolates for epidemiological investigations.

Results

Among the 411 S. pneumoniae isolates analyzed, the most prevalent serotype was 3 (12.2%), followed by 10A (9.5%), 34 (7.3%), 19A (6.8%), 23A (6.3%), 22F (6.1%), 35B (5.8%), 11A (5.1%), and others (40.9%). The coverage rates of PCV7, PCV10, PCV13, and pneumococcal polysaccharide vaccine (PPSV)23 were 7.8%, 7.8%, 28.7%, and 59.4%, respectively. Resistance rates to penicillin, ceftriaxone, erythromycin, and levofloxacin were 13.1%, 9.2%, 80.3%, and 4.1%, respectively. MDR isolates accounted for 23.4% of all isolates. Serotypes 23A, 11A, 19A, and 15B accounted for the highest proportions of total isolates at 18.8%, 16.7%, 14.6%, and 8.3%, respectively. Sequence type (ST)166 (43.8%) and ST320 (12.5%) were common among MDR isolates.

Conclusions

Non-PCV13 serotypes are increasing among invasive S. pneumoniae strains causing IPD. Differences in antimicrobial resistance were found according to the specific serotype. Continuous monitoring of serotypes and antimicrobial resistance is necessary for the appropriate management of S. pneumoniae infections.

Clinical Usefulness of BACT Count and BACT-Info Flag of UF-5000 for Screening for Urinary Tract Infection and Prediction of Gram-Negative Bacteria

BACKGROUND

A rapid and reliable screening test for urinary tract infection (UTI) is needed to reduce the turn-around time and to rule out negative results of urine culture. The aim of this study was to evaluate the performance of BACT count and BACT-Info flag of the UF-5000 for screening for UTI.

METHODS

A total of 1,063 urine specimens from April to September 2019 were included in this study. We evaluated the diagnostic performance of white blood cell (WBC) count, BACT count, BACT-Info flag, and UTI flag in UF-5000 by comparing with the urine culture results.

RESULTS

Of the urine specimens, 16.7% were culture-positive (≥ 105 CFU/mL) with 15 being yeast positive. A BACT count of > 685.3/µL showed the best diagnostic performance with 93.8% sensitivity and 90.2% specificity. We confirmed that the combination of BACT count (685.3/µL) and BACT-Info flag would be appropriate to use in a clinical laboratory (sensitivity 91.5%, specificity 90.5%). Based on this combination, the sensitivity and specificity of the Gram-negative flag were 95.5% and 94.8%.

CONCLUSIONS

We recommend the use of a combination of BACT count (685.3/µL) and BACT-Info for UTI diagnosis. This combination is more appropriate for Gram-negative bacteria, and it would be useful for selecting empirical treatment.

Lacticaseibacillus kribbianus sp. nov., isolated from pig farm faeces dump

A lactic acid bacteria isolated from pig faeces was characterized using a polyphasic approach. Cells of the strain were Gram-stain-positive, rod-shaped and facultative anaerobic. Phylogenetic analysis of 16S rRNA gene sequence indicated that the isolate belonged to the genus Lacticaseibacillus; however, the similarity to other homologues within the genus was <98 %. Analysis of housekeeping gene sequences (pheS and recA) revealed that the strain formed a sub-cluster adjacent to Lacticaseibacillus absianus and Lacticaseibacillus daqingensis. The main fatty acids of the strain is the C_18 : 1ω9c and C_16 : 0. The G+C content of the genomic DNA was 62.8 mol %. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, aminophospholipids and phospholipids. The cell-wall peptidoglycan did not contain meso-diaminopimelic acid. Thus, YH-lac21^T (=KCTC 21185=JCM 34953) represents a novel species. The name Lacticaseibacillus kribbianus sp. nov. is proposed.

Impact of estimated pulse wave velocity on cardiovascular outcomes in a general population

Background

Estimated pulse wave velocity (ePWV), a simple surrogate estimate of carotid-femoral pulse wave velocity which was gold standard for measuring aortic stiffness, has been demonstrated to predict cardiovascular (CV) outcome. However, there was limited data on its predictive capacity for CV outcomes in the general population. The study aim was to investigate the independent association between ePWV and CV outcomes in general population.

Methods

A total of 10,030 subjects aged between 40 and 69 years were followed over 18-year period in the Ansan-Ansung cohort study. Levels of ePWV, which was calculated from an equation based on age and mean blood pressure, were categorized according to quartiles. A major adverse cardiovascular event (MACE) was defined as a composite of myocardial infarction, coronary artery disease, stroke, heart failure, peripheral artery disease, and cardiovascular death.

Results

The incidence rates of CV death, and MACE were 7.0% and 22.1% in the fourth (highest) quartile of ePWV and 0.1% and 4.5% in the first (lowest) quartile of ePWV. After adjusting for relevant covariates, patients with third and fourth quartile of ePWV showed significantly higher risk of CV death (hazard ratio [HR] 3.92; 95% confidence intervals [CI] 1.09–14.15 in third quartile and HR 8.53; 95% CI 2.13–34.10 in fourth quartile), and MACE (HR 1.54; 95% CI 1.15–2.08 in third quartile and HR 1.56; 95% CI 1.05–2.32) compared to the reference of first (lowest) quartile of ePWV. However, there were no improvement of C statistic for CV death and MACE when adding ePWV to the Cox regression models with 10-year atherosclerotic cardiovascular disease (ASCVD) risk.

Conclusion

These results suggest that ePWV predicted CV death and MACE in general population. The value of ePWV, a simple and useful indicator of aortic stiffness, is expected to serve as a potential marker to identify high risk groups of CV event in general population.

Funding Acknowledgement

Type of funding sources: None.

Influence of concomitant percutaneous transluminal angioplasty with percutaneous coronary intervention on outcomes in patients with stable lower extremity artery disease

Background

Patients with stable lower extremity artery diseases (LEAD) frequently present with coronary artery diseases; thus, concomitant percutaneous transluminal angioplasty (PTA) at the time of percutaneous coronary intervention (PCI) is often performed. We investigated the influence of concomitant PTA on both cardiovascular (CV) and limb outcomes in the Korean National Health Insurance Service registry.

Methods

Among 78,185 patients undergoing PCI between 2012 and 2015, 6,563 patients (279 for the PTA+PCI group vs. 6,284 for the PCI group) suffering from stable LEAD without limb ischemia were included. Major adverse CV events (MACEs) were defined as a composite of CV death, myocardial infarction (MI) and coronary revascularization. Patients were followed for at least 3 years.

Results

After 1:5 propensity score matching was conducted, 279 patients in the PTA+PCI group and 1,385 patients in the PCI group were compared. The risk of all-cause death was higher in the PTA+PCI group than in the PCI group, whereas the risks of MACE, MI, revascularization, stroke, CV death and bleeding event were not different between the 2 groups in the matched cohort. In contrast, the risks of end-stage renal diseases and unfavorable limb outcomes were higher in the PTA+PCI group than in the PCI group (Figure 1). Mediation analyses revealed that amputation and repeat Percutaneous transluminal angioplasty after discharge significantly mediated the association between the concomitant PTA and all-cause death (Figure 2).

Conclusions

CPTA at the time of PCI is not associated with an increased risk of CV events but may increase the risk of all-cause death by increasing unfavorable renal and limb outcomes in patients with stable LEAD.

Funding Acknowledgement

Type of funding sources: None.

P221 Deep dermatophytosis presented as multiple exophytic masses caused by Trichophyton rubrum in immunocompromised patient with rheumatoid arthritis; a case report

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM

 

 

Dermatophyte invades the stratum corneum and infects the skin, nails, and hair, mostly resulting in superficial infection. Deep dermatophytosis involving dermis and subcutaneous layer was rarely reported in immunocompromised state. Herein, we report a case with deep dermatophytosis caused by Trichophyton (T.) rubrum. A 71-year-old woman presented with multiple erythematous exophytic and subcutaneous nodules located on both lower legs. She was taking immunosuppressive agents for rheumatoid arthritis and had taken antifungal agents for tinea pedis and onychomycosis, which was improperly ceased. Histopathologic examination revealed pseudoepitheliomatous epidermal hyperplasia with microabscess formation in epidermis and diffuse granulomatous inflammation consisting of multinucleated giant cells, lymphocytes, neutrophils, and histiocytes in dermis. Imuunohistochemical staining with periodic acid-schiff (PAS) and Gomori methenamine silver (GMS) showed septate and branched fungal hyphae in dermis. Trichophyton rubrum was identified in fungal culture with tissue and confirmed through phylogenetic analysis of internal transcribed spacer (ITS) and large subunit regions (LSU) in ribosomal RNA. Prior to identification of causative organism, her condition deteriorated into septic shock. Amphotericin B was administered empirically for 6 days in order to prevent hematogenous dissemination and skin lesions were simultaneously resolved. Since deep dermatophytosis appears in various clinical manifestations, it is easy to be mistaken for another disease. If treatment is delayed, immunocompetent patients can progress to severe disease courses like hematogenous dissemination, so clinicians should differentiate this disease and conduct treatment at an appropriate time.

Performance of BD MAX Group B Streptococcus (GBS) Assay without Enrichment for the Detection of GBS

Group B streptococcus (GBS) is an important pathogen causing neonatal early-onset disease. We evaluated the diagnostic performance of BD Max GBS assay (Becton Dickinson, Franklin Lakes, NJ, USA) without enrichment (direct BDM) for detecting GBS using vaginal and rectal specimens in comparison with culture. In total, 716 specimens collected from 358 pregnant women between June 2018 and May 2020 were included in this study. Bacterial culture was performed using ChromID Strep B agar (bioMérieux, Marcy-l’Étoile, France), and species identification results were confirmed using the VITEK-MS system (bioMérieux). The sensitivity of direct BDM for vaginal and rectal specimens was 75.0% and 100%, respectively. Thirteen specimens showed discrepant results: 10 false-negative results in the vaginal specimens and three false-positive results in the rectal specimens. The overall agreement between direct BDM and culture was 98.9% (354/358). The final sensitivity and specificity of direct BDM were 98.5% and 99.0%, respectively. Discrepant results—one false-negative and three false-positives—were obtained for four specimens. Direct BDM shows a good diagnostic performance and will be useful for GBS screening within a few hours.

Association of Carbapenemase-Producing Enterobacterales Detected in Stream and Clinical Samples

Background

The spread of carbapenem-resistant Enterobacterales (CRE) strains has caused treatment failure and is a worldwide threat to public health. However, there are limited reports on the prevalence of carbapenemase-producing Enterobacterales (CPE) in aquatic environments and its association with clinical isolates. This study aimed to investigate the prevalence of CPE in a stream environment and its genetic relationship with clinical isolates in Korea.

Methods

A total of 4,582 water samples were collected from 94 streams. Multiplex PCR and sequencing were used to detect and identify six carbapenemase genes. Multi-locus sequence typing (MLST) was performed to investigate the genetic relatedness between the environmental strains and clinical isolates.

Results

A total of 133 CRE strains were isolated from the streams. Klebsiella pneumoniae was the most common CRE (45.9%), followed by Enterobacter cloacae complex (29.3%), Escherichia coli (13.5%), Raoultella ornithinolytica (5.3%), and Citrobacter freundii (2.3%). Ninety (67.7%) isolates carried carbapenemase genes. K. pneumoniae carbapenemase-2 (36.7%) and New Delhi metallo-β-lactamase-5 (32.2%) were the common carbapenemases detected. Sequence type (ST)307 and ST11 K. pneumoniae strains harboring the bla_KPC-2 gene were the most prevalent in stream and patient samples.

Conclusion

CPE was highly prevalent in streams and closely related to the isolates obtained from patients. Therefore, continuous monitoring of stream environments is required to control the spread of carbapenem resistance.

Characteristics of Clonal Complex Changes and Quinolone Resistance-Determining Region Mutations of Levofloxacin-Resistant Streptococcus pneumoniae in South Korea

Streptococcus pneumoniae is the most common causative agent of community-acquired pneumonia and invasive pneumococcal diseases with high mortality rates. The aims of this study were to evaluate clonal complex (CC) changes of levofloxacin-resistant S. pneumoniae (LRSP) strains and to investigate the relationship between levofloxacin resistance and pneumococcal serotypes. We analyzed the antimicrobial susceptibility of 145 LRSP strains to 18 antimicrobial agents and the quinolone resistance-determining region mutation. Multilocus sequence typing was performed to investigate the genetic relatedness among LRSP strains. Most LRSP strains (96.6%) were multidrug resistant and had simultaneous mutations in gyrA, parC, and parE (91.7%). The serotypes 11A (44.1%) and 13 (14.5%) accounted for 58.6% of LRSP strains, and 32.0% were nonvaccine serotypes. Most LRSP strains were grouped as CC8279 (N = 83; 57.2%), CC189 (N = 10; 6.9%), or CC320 (N = 5; 3.4%). CC8279 was commonly combined with serotypes 11A and 13. There were numerous changes of serotype and CC accompanying the emergence and spread of LRSP. Continuous monitoring of changes in the serotype and sequence type of LRSP is required to follow the spread of LRSP for public health monitoring.

Serotype Distribution and Antimicrobial Resistance of Salmonella Isolates in Korea between 2016 and 2017

Salmonella is one of the major causes of food-borne infections. We investigated the serotype distribution and antimicrobial resistance of Salmonella isolates collected in Korea between January 2016 and December 2017. In total, 669 Salmonella isolates were collected from clinical specimens at 19 university hospitals. Serotyping was performed according to the Kauffmann–White scheme, and antimicrobial susceptibility was tested using Sensititre EUVSEC plates or disk diffusion. Among the strains, C (39.8%) and B (36.6%) were the most prevalent serogroups. In total, 51 serotypes were identified, and common serotypes were S. enterica serovar I 4,[5],12:i:- (16.7%), S. Enteritidis (16.1%), S. Bareilly (14.6%), S. Typhimurium (9.9%), and S. Infantis (6.9%). The resistance rates to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole were 32.6%, 12.1%, and 8.4%, respectively. The resistance rates to cefotaxime and ciprofloxacin were 8.1% and 3.0%, respectively, while 5.4% were multidrug-resistant. S. enterica serovar I 4,[5],12:i:- and S. Enteritidis were highly prevalent, and there was an increase in rare serotypes. Multidrug resistance and ciprofloxacin resistance were highly prevalent. Periodic investigations of Salmonella serotypes and antimicrobial resistance are needed.

Major Bloodstream Infection-Causing Bacterial Pathogens and Their Antimicrobial Resistance in South Korea, 2017-2019: Phase I Report From Kor-GLASS

To monitor national antimicrobial resistance (AMR), the Korea Global AMR Surveillance System (Kor-GLASS) was established. This study analyzed bloodstream infection (BSI) cases from Kor-GLASS phase I from January 2017 to December 2019. Nine non-duplicated Kor-GLASS target pathogens, including Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter spp., and Salmonella spp., were isolated from blood specimens from eight sentinel hospitals. Antimicrobial susceptibility testing, AMR genotyping, and strain typing were carried out. Among the 20,041 BSI cases, 15,171 cases were caused by one of the target pathogens, and 12,578 blood isolates were collected for the study. Half (1,059/2,134) of S. aureus isolates were resistant to cefoxitin, and 38.1% (333/873) of E. faecium isolates were resistant to vancomycin. Beta-lactamase-non-producing ampicillin-resistant and penicillin-resistant E. faecalis isolates by disk diffusion method were identified, but the isolates were confirmed as ampicillin-susceptible by broth microdilution method. Among E. coli, an increasing number of isolates carried the bla _CTX-M-27 gene, and the ertapenem resistance in 1.4% (30/2,110) of K. pneumoniae isolates was mostly (23/30) conferred by K. pneumoniae carbapenemases. A quarter (108/488) of P. aeruginosa isolates were resistant to meropenem, and 30.5% (33/108) of those carried acquired carbapenemase genes. Over 90% (542/599) of A. baumannii isolates were imipenem-resistant, and all except one harbored the bla _OXA-23 gene. Kor-GLASS provided comprehensive AMR surveillance data, and the defined molecular mechanisms of resistance helped us to better understand AMR epidemiology. Comparative analysis with other GLASS-enrolled countries is possible owing to the harmonized system provided by GLASS.

Associations between changing patterns of ST-T waves morphologies in rest electrocardiography and cardiovascular risk in an asymptomatic low risk population: a report from Ansan-Ansung cohort study

Background

While clinical significance of ST-T wave abnormalities (STA) in rest electrocardiography (ECG) on long-term cardiovascular outcomes has been on debate, few studies have been reported on the association between the changes in ST-T waves in rest ECG and cardiovascular outcomes in low risk populations. We investigate the changing patterns of STA in rest ECG and the predictive value of the changes in ST-T wave in rest ECG for cardiovascular events in an asymptomatic general population.

Methods

A longitudinal community-based cohort study was conducted for 12 years. Koreans aged 40–69 years were followed biennially through scheduled revisit for comprehensive assessments. Among 10,030 participants, 6,648 participants who did not have any cardiovascular diseases, angina-related symptoms or pathologic Q waves in rest ECG at baseline were included for analysis. Changes in STAs were defined using the changes between ECG at baseline and that at the first revisit. A major adverse cardiovascular events was defined as a composite of cardiac death, myocardial infarction, clinical diagnosis of coronary artery disease and stroke.

Results

Among 5,924 participants without STA at baseline, only 187 participants (3.2%) developed new STA. Among 724 patients (10.9%) with STA at baseline, 274 patients (37.8%) persistently showed STA at the first revisit. MACEs occurred more frequently in the participants persistently with STA and those with newly-developed STA than in the participants persistently without STA (Figure 1). Multivariate Cox-proportional hazard models showed that a higher risk of MACE was only associated with the persisted STA (HR 1.69; 95% CI 1.10–2.63). In participants with baseline STA, persisted T-wave flattening was associated with a higher risk of MACE, whereas T-wave inversion, either persisted or fluctuated was not associated with a higher risk of MACE, compared with persistent absence of STA (Figure 2). In the participants without baseline STAs, multivariate Cox-proportional hazard model showed that newly-developed T-wave flattening (HR 1.85; 95% CI 0.20–2.84), not T-wave inversion (HR 1.50; 95% CI 0.85–2.65) was associated with a higher risk of MACE. Survival receiver operating curve analysis showed that the changes in STAs had a C-index of 0.538 (95% CI 0.511–0.558), a sensitivity of 13.0% and a specificity of 92.5% and add only a small value to the predictive power of 10-year atherosclerotic cardiovascular diseases risk estimator (C-index without STA changes 0.708 [0.681–0.736] vs. C-index with STA changes 0.721 [0.694–0.748]).

Conclusions

STAs uncommonly developed while frequently disappeared spontaneously in the asymptomatic general population. Persisted STA and newly developed STA in rest ECG were predictive of future cardiovascular events in the asymptomatic general population. However, the changes in STAs did not significantly improve the predictive value of the conventional risk estimator, when added.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Research Foundation of Korea Figure 1Figure 2

Simulation and validation for count-based binary decision of target blood pressure achievement in home blood pressure monitoring data analysis for clinical practice

Introduction

Home blood pressure monitoring (HBPM) is a useful tool to identify hypertension and to decide whether a patient's blood pressure (BP) is controlled. The use of automatized oscillometric BP measurement devices has become increasingly popular with help of information technology and internet of things to the devices. However, applying HBPM to daily clinical practices is still challenging, because most patients with hypertension are in age groups not familiar to digital devices and internet and high BP criteria using average home BP values are often useless in outpatient clinics without easily accessible average BP calculation tools. Therefore, we developed a simple and straightforward method to interpret HBPM through counts of BP ≥135/85 mmHg.

Methods

We simulated 400 cases of HBPM using a random number generator function in statistical software. The simulated average home systolic BP (SBP) and its standard deviation (SD) were 125±15 mmHg and 12±5 mmHg and the number of HBP readings was 24 times. The simulated diastolic BP (DBP) was randomly selected to 50–75% of the SBP. The validation of the binary interpretation method was conducted using actual HBPM data from 386 subjects in a rural area of South Korea. Receiver operating characteristics curve analysis was conducted, and linear regression and logarithmic models were fitted between the numbers of home BP ≥135/85 mmHg and mean BP. Hypertension was defined with average home BP ≥135/85 mmHg.

Results

In the simulated cohort, hypertension was presented in 197 cases (49.3%). The C-index of the numbers of BP readings ≥135/85 mmHg was 0.994 (95% confidence interval [CI] 0.990–0.998), and ≥12 of 24 BP readings ≥135/85 mmHg showed a sensitivity of 95.4%, a specificity of 95.1% and an accuracy of 95.3% for the diagnosis of hypertension. In validation cohort, the numbers of home BP measurements varied from 8 to 81 times. The validation cohort similarly showed that the C-index of the ratio between the number of high BP readings (≥135/85 mmHg) to the number of BP measurements (R-NHBP/NBP) was 0.985 (95% CI, 0.976–0.994) and the best accuracy was shown at R-NHBP/NBP of ≥0.45. R-NHBP/NBP of ≥0.5 showed a sensitivity of 0.957, a specificity of 0.907 and an accuracy of 0.927. The accuracy of the R-NHBP/NBP of ≥0.5 decreased as SD and the range of SBP increased, whereas it did not change with the number of measurements (Figure 1). R-NHBP/NBP &lt;0.2 predicted normotension and R-NHBP/NBP &gt;0.8 predicted hypertension in 95% confidence. Mean widths of the 95 prediction intervals for the average SBP and DBP were 18.2 mmHg and 12.6 mmHg, respectively (Figure 2).

Conclusion

Counting the number of BP ≥135/85 mmHg can provide accurate assessments for the BP levels. R-NHBP/NBP of ≥0.5 is a simple and accurate marker of high BP in HBPM, and R-NHBP/NBP could be a useful tool to assess BP levels in patients practicing HBPM.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Risk Factors for Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Community-Onset Bloodstream Infection: Impact on Long-Term Care Hospitals in Korea

Background

The prevalence of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) in the community has increased worldwide due to multifactorial reasons. ESBL-EC bloodstream infection (BSI) complicates the decision for proper antimicrobial administration. In this multicenter study, we investigated the prevalence, risk factors, and molecular background of community-onset (CO) ESBL-EC BSI.

Methods

We included data for all episodes of ESBL-EC BSI of community origin from May 2016 to April 2017 obtained from the Korean national antimicrobial resistance surveillance system, which comprises six sentinel hospitals. Data, including previous history of admission and use of antimicrobials and medical devices before BSI, were collected, along with microbiological analysis results.

Results

Among 1,189 patients with CO BSI caused by E. coli, 316 (27%) were identified as ESBL producers. History of admission, especially to a long-term care hospital (LTCH), and previous use of β-lactams/β-lactamase inhibitors, carbapenem, lincosamide, aminoglycoside, and extended-spectrum cephalosporin were independent risk factors for CO ESBL-EC BSI; admission to an LTCH showed the highest odds ratio (3.8, 95% confidence interval 2.3-6.1). The most common genotype was CTX-M-15 (N=131, 41%), followed by CTX-M-14 (N=86, 27%). ST131 was the most common sequence type among ESBL-EC groups (57%).

Conclusions

In Korea, 27% of CO E. coli BSI were caused by ESBL producers. From perspectives of empirical treatment and infection control, history of admission to an LTCH and antimicrobial use should be noted.

Retrograde transvenous obliteration for the prevention of variceal rebleeding in patients with hepatocellular carcinoma: a multicentre retrospective study

AIM

To evaluate the effectiveness and safety of retrograde transvenous obliteration (RTO) for the prevention of variceal rebleeding variceal rebleeding in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This multicentre retrospective study enrolled 79 patients with HCC who underwent RTO for the prevention of variceal rebleeding. Successful occlusion of the gastrorenal shunt and obliteration of the gastric varices were achieved in 74 patients, with a technical success rate of 93.7%. Of the remaining 74 patients (mean age, 64.9±10.3 years; 56 men), 66 (90.4%) had gastroesophageal varices and seven (9.6%) had isolated gastric varices. Thirty-two patients (43.8%) underwent balloon-occluded RTO, 40 patients (54.8%) underwent plug-assisted RTO, and one patient (1.4%) underwent coil-assisted RTO. No patients had major procedural complications.

RESULTS

Rebleeding occurred in seven patients (9.6%) during the follow-up period. The 6-week and 1-year actuarial probabilities of patients remaining free of rebleeding were 90.8±3.6% and 88.6±4.1%, respectively. The median survival was 12.6 (95% confidence interval [CI] 8-17.3) months. The 6-week, 1-year, and 3-year actuarial probabilities of survival were 83.2±4.4%, 51.1±6.6%, and 32.7±7%, respectively. New or worsening ascites and oesophageal varices occurred in 12 (16.4%) and 13 patients (17.8%), respectively, during the follow-up period. Overt hepatic encephalopathy occurred in one patient (1.4%) during the follow-up period. The Child-Pugh score remained comparable to that at baseline at 1 and 3 months.

CONCLUSION

RTO was effective and safe in preventing variceal rebleeding in patients with HCC.

Safety and efficacy of transarterial embolisation for treatment of dorsal pancreatic artery haemorrhage

AIM

To evaluate the safety and efficacy of transarterial embolisation (TAE) of dorsal pancreatic artery (DPA) haemorrhage.

MATERIALS AND METHODS

Nineteen consecutive patients (M:F = 16:3, mean age 59.6 years) who underwent TAE of DPA in three tertiary medical centres between January 2001 to January 2020 were reviewed retrospectively. Angiographic features and the technical and clinical outcomes of TAE were analysed.

RESULTS

The clinical presentations were a bloody drain from the Jackson-Pratt drainage tube (n=8), melaena (n=7), abdominal pain (n=4), and haematochezia (n=3). Angiographic findings included pseudoaneurysm (n=14), contrast media extravasation (n=4), or abrupt cut-off of the arterial branch (n=1). The NBCA (N-butyl-cyanoacrylate; n=4), microcoils (n=4), and a combination of these agents (n=7) were used as embolic agents. The most common origin of the DPA in the present study cohort was the splenic artery (n=7), followed by the coeliac trunk (n=4), common hepatic artery (n=4), and superior mesenteric artery (n=4). Technical and clinical success rates were 100% and 84.2% (16/19), respectively. Of the three clinically unsuccessful cases, two patients were revealed to have newly developed bleeding from another artery. The other patient expired 1 day after the TAE procedure due to a progression of hepatic failure. In one patient, an asymptomatic non-target embolisation occurred in the right posterior tibial artery as a procedure-related complication. No major complications were observed.

CONCLUSION

TAE is safe and effective for the management of bleeding from the DPA. It is important to be aware of the DPA as a potential bleeding source, including the relevant clinical characteristics.

Low-dose CT angiography of the lower extremities: a comparison study of image quality and radiation dose

AIM

To investigate the image quality and radiation dose of ultralow-dose (ULD) and low-dose (LD) lower-extremity computed tomography (CT) angiography (LE-CTA) using the advanced modelled iterative reconstruction (ADMIRE) algorithm to detect peripheral arterial disease (PAD) in comparison with standard-dose (SD) CT.

MATERIALS AND METHODS

One hundred and seven consecutive patients were examined using LE-CTA at 70 kVp and a dual-source scanner to achieve three image sets using 30% (ULD), 70% (LD), and 100% (SD) tube loads. Qualitative analysis was conducted by examining the three image sets for overall quality. The image quality of arterial segments was analysed by two independent readers. In addition, the CT dose index (CTDI_vol) was measured in the three image sets.

RESULTS

The mean overall quality scores were 3.4±0.6 for ULD CT, 3.9±0.3 for LD CT, and 3.9±0.2 for SD CT. Both readers scored the arterial segments as 2-4 (adequate-excellent) in the three image sets. In addition, 89.4% (93/104) and 54.8% (57/104) segments of PAD with calcified plaques were scored 4 between SD and LD CT and between SD and ULD CT, respectively, and 45.2% (47/104) segments had a lower score by one point in ULD CT compared with SD CT. The mean CTDI_vol was 4.1±1.1 mGy for SD CT, 2.9±0.8 mGy for LD CT, and 1.2±0.3 mGy for ULD CT.

CONCLUSIONS

LD/ULD CT at 70 kVp using ADMIRE reconstruction enables a reduction in the radiation dose while enabling adequate evaluation or follow-up of PAD based on LE-CTA.

A Novel KPC Variant KPC-55 in Klebsiella pneumoniae ST307 of Reinforced Meropenem-Hydrolyzing Activity

A novel Klebsiella pneumoniae carbapenemase (KPC) variant, KPC-55, produced by a K. pneumoniae ST307 strain was characterized. K. pneumoniae strain BS407 was recovered from an active surveillance rectal swab of a patient newly admitted to a general hospital in Busan, South Korea. Carbapenemase production was confirmed by the modified Hodge test, and the MICs of β-lactams were determined by the broth microdilution method. The whole genome was sequenced. Cloning and expression of the bla_KPC–55 gene in Escherichia coli and MIC determination were performed. The enzyme KPC-55 was used for kinetic assays against β-lactams and compared with the KPC-2 enzyme. The new allele of the bla_KPC gene had a T794A alteration compared to the bla_KPC–2 gene, resulting in the amino acid substitution Y264N in the middle of the β9-sheet. Compared to the KPC-2-producing strain, the KPC-55-producing strain exhibited a lower level of resistance to most β-lactam drugs tested, however, the KPC-55 enzyme catalyzed aztreonam and meropenem at an increased efficiency compared to the catalytic activity of KPC-2. KPC subtypes could have varied phenotypes due to alterations in amino acid sequences, and such an unexpected resistance phenotype emphasizes the importance of detailed characterizations for the carbapenemase-producing Enterobacterales.

Prevalence of Eleven Infectious Viruses Causing Diarrhea in Korea

Rotavirus and norovirus are well-known causes of viral infectious diarrhea. There are few reports on diarrhea caused by other viruses in Korea, although cases of gastroenteritis attributable to other viruses are increasing worldwide. The aims of this study were to detect various causes of viral diarrhea and to investigate their prevalence. A total of 801 fecal specimens submitted to a clinical microbiology laboratory for the detection of diarrheal viruses were included. We sought to detect rotavirus A/B/C, adenovirus, astrovirus, norovirus GI/GII, sapovirus, Aichi virus, human parechovirus, enterovirus, human cosavirus, human bocavirus, and Saffold virus using multiplex reverse transcription polymerase chain reaction (RT-PCR). At least one diarrheal virus was detected in 223 (27.8%) fecal specimens. Among them, two viruses were detected in 11 specimens. Rotavirus A was most common (17.1%; N = 137), followed by norovirus GII (5.0%; N = 40), enterovirus (4.2%; N = 34), adenovirus (1.0%; N = 8), astrovirus (1.0%; N = 8), human parechovirus (0.6%; N = 5), and human bocavirus (0.2%; N = 2). Rotaviruses B and C, norovirus GI, sapovirus, Aichi virus, human cosavirus, and Saffold virus were not detected. We confirmed that various diarrheal viruses can be detected in fecal specimens. We must consider the possibility of viruses other than rotavirus and norovirus being present in cases of diarrhea.

Prevalence and Characteristics of Carbapenemase-Producing Enterobacteriaceae in Three Tertiary-Care Korean University Hospitals between 2017 and 2018

The aim of this study was to evaluate the prevalence and characteristics of carbapenemase-producing Enterobacteriaceae (CPE) from 3 tertiary-care Korean university hospitals between 2017 and 2018. Non-duplicated clinical isolates of Enterobacteriaceae showing resistance to any carbapenem agents were collected prospectively from 3 tertiary university hospitals between 2017 and 2018. The presence of carbapenemase genes was detected by multiplex PCR and sequencing for bla_KPC, bla_VIM, bla_NDM, bla_IMP, bla_OXA, and bla_GES was performed. Among the 690 potential carbapenem-resistant Enterobacteriaceae (CRE) isolates, 66.8% (N = 461) were CPE. The species distribution of CPE was as follows: Klebsiella pneumoniae was most common (75.9%), followed by Escherichia coli (15.0%), Citrobacter freundii (4.6%), Enterobacter cloacae (2.6%), Klebsiella. aerogenes (0.7%), and Klebsiella. oxytoca (0.4%). All 11 CPE genes were detected, particularly K. pneumoniae carbapenemase (KPC)-2 (87.6%), New Delhi metallo-β-lactamase (NDM)-1 (7.4%), NDM-5 (1.7%), KPC-3 (1.3%), oxacillinase (OXA)-232 (1.1%), and OXA-181 (1.1%). Six isolates produced 2 or 3 carbapenemases. The majority of the carbapenemase-producing C. freundii tested positive for NDM-1. We confirmed a high proportion of CPE among the CRE isolates with a high prevalence of KCP-2-producing K. pneumoniae and E. coli. Therefore, there is a need for undertaking continuous surveillance to monitor the prevalence of CPE.

Supramolecular Regulation of Polydopamine Formation by Amyloid Fibers

Polydopamine (PD) and melanin species are chemically complex systems, the formation and properties of which are incompletely understood. Inspired by the role of functional amyloids in melanin biosynthesis, this paper examines the influences of the supramolecular structure of amyloids on oxidative polymerization of dopamine. Kinetic analyses on the formation of PD species in the presence of hen egg white lysozyme (HEWL) fibers or soluble HEWL revealed that both forms gave rise to the total quantity of PD species, but the rate of their formation could be accelerated only by the amyloid form. PD species formed with HEWL fibers showed a morphology of bundled fibers, whereas those with soluble HEWL had a mesh-like structure. Amyloid fibers of recombinant Pmel17 had properties similar to those of HEWL fibers in modulating PD formation. The results presented here suggest how nature designs functionality with an amyloid structure and can help understand and engineer chemistries of other functional amyloids.

Radiomics Study of Thyroid Ultrasound for Predicting BRAF Mutation in Papillary Thyroid Carcinoma: Preliminary Results

BACKGROUND AND PURPOSE

It is not known how radiomics using ultrasound images contribute to the detection of BRAF mutation. This study aimed to evaluate whether a radiomics study of gray-scale ultrasound can predict the presence or absence of B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutation in papillary thyroid cancer.

MATERIALS AND METHODS

The study retrospectively included 96 thyroid nodules that were surgically confirmed papillary thyroid cancers between January 2012 and June 2013. BRAF mutation was positive in 48 nodules and negative in 48 nodules. For analysis, ROIs from the nodules were demarcated manually on both longitudinal and transverse sonographic images. We extracted a total of 86 radiomics features derived from histogram parameters, gray-level co-occurrence matrix, intensity size zone matrix, and shape features. These features were used to build 3 different classifier models, including logistic regression, support vector machine, and random forest using 5-fold cross-validation. The performance including accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve, of the different models was evaluated.

RESULTS

The incidence of high-suspicion nodules diagnosed on ultrasound was higher in the BRAF mutation-positive group than in the mutation-negative group (P  =  .004). The radiomics approach demonstrated that all classification models showed moderate performance for predicting the presence of BRAF mutation in papillary thyroid cancers with an area under the curve value of 0.651, accuracy of 64.3%, sensitivity of 66.8%, and specificity of 61.8%, on average, for the 3 models.

CONCLUSIONS

Radiomics study using thyroid sonography is limited in predicting the BRAF mutation status of papillary thyroid carcinoma. Further studies will be needed to validate our results using various diagnostic methods.

Identification of Nontuberculous Mycobacteria from Clinical Isolates and Specimens using AdvanSure Mycobacteria GenoBlot Assay

The aim of this study was to evaluate the clinical performance of AdvanSure GenoBlot assay using nontuberculous mycobacteria (NTM) isolates and clinical specimens. A total of 136 NTM isolates and 176 clinical specimens were used in this study. AdvanSure Mycobacteria GenoBlot assay was performed according to the manufacturer's instructions. We compared the results with those of 16S rRNA and rpoB genes sequencing. Out of the 136 NTM isolates, 111 (81.6%) were correctly identified to the species level using the GenoBlot assay. The final concordance rate was 89.7% (122/136), including 11 Mycobacterium genus positive control (GPC) results for uncommon NTM. The most common NTM, M. avium, M. fortuitum, M. gordonae, M. intracellulare, M. chelonae, M. abscessus, and M. kansasii, were correctly identified using the GenoBlot assay. For 176 organisms in clinical specimens, 117 were identified to the species level, including single species for 111 specimens and two species for 6 specimens. The final detection and identification rates for clinical specimens were 94.9% and 66.5%, respectively. The AdvanSure GenoBlot assay performs well in identifying the most common NTM, and would be useful in a clinical laboratory.

Different molecular characteristics and antimicrobial resistance profiles of Clostridium difficile in the Asia-Pacific region

Molecular epidemiology of Clostridium difficile infection (CDI) has been extensively studied in North America and Europe; however, limited data on CDI are available in the Asia-Pacific region. A multicentre retrospective study was conducted in this region. C. difficile isolates were subjected to multilocus sequence typing (ST) and antimicrobial susceptibility testing. Totally, 394 isolates were collected from Hangzhou, Hong Kong, China; Busan, South Korea; Fukuoka, Japan; Singapore; Perth, Sydney, Australia; New York, the United States. C. difficile isolates included 337 toxin A-positive/B-positive/binary toxin-negative (A⁺B⁺CDT^-), 48 A^-B⁺CDT^-, and nine A⁺B⁺CDT⁺. Distribution of dominant STs varied geographically with ST17 in Fukuoka (18.6%), Busan (56.0%), ST2 in Sydney (20.4%), Perth (25.8%). The antimicrobial resistance patterns were significantly different among the eight sites (χ² = 325.64, p < 0.001). Five major clonal complexes correlated with unique antimicrobial resistances. Healthcare-associated (HA) CDI was mainly from older patients with more frequent antimicrobial use and higher A^-B⁺ positive rates. Higher resistance to gatifloxacin, tetracycline, and erythromycin were observed in HA-CDI patients (χ² = 4.76-7.89, p = 0.005-0.029). In conclusion, multiple C. difficile genotypes with varied antimicrobial resistance patterns have been circulating in the Asia-Pacific region. A^-B⁺ isolates from older patients with prior antimicrobial use were correlated with HA-CDI.

Antimicrobial resistance and virulence factors of Klebsiella pneumoniae affecting 30 day mortality in patients with bloodstream infection

Objectives

To investigate the risk factors of patients with Klebsiella pneumoniae (KP) bloodstream infection (BSI) with a focus on antimicrobial resistance and virulence factors.

Methods

All KP BSI patients (n = 579) from six general hospitals during a 1 year period were included in this study. The risk factors of hosts and causative KP isolates were assessed to determine associations with the 30 day mortality of KP BSI patients by multivariate Cox hazards modelling.

Results

The 30 day mortality rate of KP BSI patients was 16.9% (98/579). Among the host-associated factors, increased SOFA score and leucopenia status exhibited strong associations with increased 30 day mortality. Among the pathogenic factors, carriage of the pks gene cluster (adjusted HR 1.80; 95% CI 1.16-2.79) was a risk factor, especially when accompanied by MDR. In this regard, KP isolates of the wzi50 capsular type (n = 22) frequently harboured pks (63.6%, 14/22) and ybtA (68.2%, n = 15) and mostly exhibited MDR (63.6%, n = 14), resulting in increased 30 day mortality. In contrast, hypermucoviscous KP isolates showed an inverse association with 30 day mortality (adjusted HR 0.55; 95% CI 0.33-0.90).

Conclusions

Despite the reported virulence of hypermucoviscous KP strains, they were associated with good prognoses in KP BSI patients. Importantly, carriage of the pks gene cluster, which is responsible for the synthesis of colibactin, was a relevant marker of early mortality.

Paenibacillus oralis sp. nov., Isolated from Human Subgingival Dental Plaque of Gingivitis Lesion

A Gram-stain-negative, facultative anaerobic, spore-forming, motile, and rod-shaped bacterium, strain ChDC PVNT-B20^T, was isolated from the human subgingival dental plaque of a gingivitis lesion. Phylogenetic analysis based on the 16S ribosomal RNA gene (16S rDNA) showed that the strain belonged to the genus Paenibacillus. BLAST analysis of 16S rDNA sequence of the strain displayed high identity to those of Paenibacillus faecis DSM 23593^T (97.7% similarity) and Paenibacillus macerans ATCC 8244^T (97.6% similarity). Draft genome of strain ChDC PVNT-B20^T was composed of 8,112,407 bp. The DNA G+C content of the strain was 51.3 mol%. Average nucleotide identity values between strain ChDC PVNT-B20^T and P. faecis DSM 23593^T or P. macerans ATCC 8244^T were 75.71% and 91.5%, respectively. Genome-to-genome distance values between strain ChDC PVNT-B20^T and P. faecis DSM 23593^T or P. macerans ATCC 8244^T were 21.6% (19.3-24.0%) and 44.9% (42.3-47.4%), respectively. Major cellular fatty acids of strain ChDC PVNT-B20^T were anteiso-C_15:0 (43.4%), C_16:0 (16.6%), iso-C_16:0 (14.4%), and anteiso-C_17:0 (12.4%). The sole respiratory quinone of the strain was menaqinone-7. Major polar lipids of the strain were phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), and one unidentified glycolipid (GL). Minor polar lipids were one unidentified aminolipid (AL), one unidentified phospholipid (PL), and three unidentified lipids (L1-L3). Based on these results, strain ChDC PVNT-B20^T is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus oralis sp. nov. is proposed. Type strain is ChDC PVNT-B20^T (= KCOM 3021^T = JCM 33462 ^T).

Serotype Distribution and Antimicrobial Resistance of Invasive and Noninvasive Streptococcus pneumoniae Isolates in Korea between 2014 and 2016

Background

Several factors contribute to differences in Streptococcus pneumoniae serotype distribution. We investigated the serotype distribution and antimicrobial resistance of S. pneumoniae isolated between 2014 and 2016 in Korea.

Methods

We collected a total of 1,855 S. pneumoniae isolates from 44 hospitals between May 2014 and May 2016, and analyzed the serotypes by sequential multiplex PCR. We investigated the distribution of each serotype by patient age, source of the clinical specimen, and antimicrobial resistance pattern.

Results

The most common serotypes were 11A (10.1%), followed by 19A (8.8%), 3 (8.5%), 34 (8.1%), 23A (7.3%), and 35B (6.2%). The major invasive serotypes were 3 (12.6%), 19A (7.8%), 34 (7.8%), 10A (6.8%), and 11A (6.8%). Serotypes 10A, 15B, 19A, and 12F were more common in patients ≤5 years old, while serotype 3 was more common in patients ≥65 years old compared with the other age groups. The coverage rates of pneumococcal conjugate vaccine (PCV)7, PCV10, PCV13, and pneumococcal polysaccharide vaccine 23 were 11.8%, 12.12%, 33.3%, and 53.6%, respectively. Of the 1,855 isolates, 857 (46.2%) were multi-drug resistant (MDR), with serotypes 11A and 19A predominant among the MDR strains. The resistance rates against penicillin, cefotaxime, and levofloxacin were 22.8%, 12.5%, and 9.4%, respectively.

Conclusions

There were significant changes in the major S. pneumoniae serotypes in the community. Non-PCV13 serotypes increased in patients ≤5 years old following the introduction of national immunization programs with the 10- and 13-polyvalent vaccines.

Interventional treatment of arterial injury during blind central venous catheterisation in the upper thorax: experience from two centres

AIM

To evaluate the safety and clinical efficacy of interventional treatment for arterial injury during blind, central venous catheterisation in the upper thorax at two tertiary medical centres.

MATERIALS AND METHODS

Eighteen consecutive patients (37-81 years; M:F=8:10) who underwent interventional treatment for the arterial injuries that occurred during central venous catheterisation without any imaging guidance between November 2007 and December 2018 were included. Clinical data, angiographic findings, detailed interventional procedures, and technical and clinical outcomes were analysed retrospectively.

RESULTS

Arterial injury sites were the subclavian artery/branches (n=12), axillary artery/branches (n=2), and common carotid artery (n=4). The target vein was not correlated with the corresponding artery/branches in eight patients (44.4%); internal jugular vein to subclavian artery branches. Angiographic findings were pseudoaneurysm (66.7%, 12/18), contrast medium extravasation (22.2%, 4/18), or both (11.1%, n=2). A stent graft was inserted for the main trunk injuries in nine patients, with (n=2) or without (n=7) prior arterial branch embolisation to prevent potential endoleak, while embolisation for the arterial branch injuries was performed in nine patients. Direct percutaneous access with thrombin injection to the pseudoaneurysm or residual arteriovenous fistula was utilised in two. The technical and clinical success rate was 94.4% (17/18) each. There were no procedure-related complications. In one patient without immediate clinical success, there was a persistent pseudoaneurysm after stent graft placement, which was treated with in-stent balloon dilation.

CONCLUSION

Interventional treatment serves as a safe and effective treatment modality for inadvertent arterial injury related to blind, central venous access catheterisation in the upper thorax.

476. Risk Factors of Community-Onset Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae Bacteremia in South Korea Using National Health Insurance Claims Data

Background

Antibiotic resistance is a significant threat to public health not only in healthcare setting but also in community because antimicrobial-resistant infections can be transmitted in community. Although it is essential to know whether there are particular reasons that caused antibiotic-resistant infection in community, there is lack of evidence regarding risk factors for community-onset extended-spectrum β-lactamase-producing Klebsiella pneumoniae bloodstream infection (ESBL-KP BSI) in South Korea. In the present study, we aimed to reveal risk factors for community-onset ESBL-KP BSI.

Methods

From May 2016 to April 2017, patients with community-onset KP BSI (n = 408) from six sentinel hospitals in South Korea were included. The hospitals are located in different districts throughout South Korea, and had a total of 5,194 beds, ranged from 715 to 1,050 beds per hospital. Admission history and previous usage of antibiotics and medical devices before bacteremia were acquired from National Health Insurance claims data. Risk factors of ESBL-KP BSI were analyzed with a multivariable logistic regression model. PCR and sequencing for the identification of genes encoding ESBLs, and multilocus sequence typing were performed.

Results

Of 408 patient of community-onset KP BSI, 70 (17%) were ESBL-KP BSI patients. ESBL-KP isolates most frequently carried CTX-M-1-group ESBLs (74%, n = 52), followed by CTX-M-9-group ESBLs (16%, n = 11). Most prevalent sequence type (ST) among ESBL-KP isolates was ST48 (14%, n = 10). Among non-ESBL-KP isolates, ST23 was most prevalent (21%, n = 70). Analyzing with multivariate analysis, recent admission to long-term care hospital within 3 months (OR, 5.7; 95% CI, 2.1–15.6; P = 0.001), previous usage of trimethoprim-sulfamethoxazole (OR, 11.5; 95% CI, 2.7–48.6; P = 0.001), expanded-spectrum cephalosporin (OR, 2.2; 95% CI, 1.2–3.9; P = 0.01), and previous use of urinary catheter (OR, 2.3; 95% CI, 1.1–4.5; P = 0.02) were identified as independent risk factors for community-onset ESBL-KP BSI.

Conclusion

Recent admission to long-term care hospital, use of urinary catheter, recent usage of antibiotics were identified as risk factors for community-onset ESBL-KP BSI. Strict antibiotic stewardship and infection control measures in long-term care hospital are needed.

Disclosures

All authors: No reported disclosures.

1457. Antimicrobial Resistance of Urinary Tract Infection Pathogens in South Korea: A Surveillance Report of the One-Year Assessment in 2017

Background

Korean Antimicrobial Surveillance System (Kor-GLASS) was established in 2016, which is compatible with the Global Antimicrobial Resistance Surveillance System launched by WHO. Here, we report a one-year assessment of Kor-GLASS in 2017, focusing on the antimicrobial resistance of urine isolates.

Methods

Non-duplicated clinical isolates of E. coli and K. pneumoniae recovered from urine cultures were collected from 8 sentinel hospitals. Demographic information, infection origin (hospital origin or community origin), and admission type were investigated. Bacterial species were confirmed using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. Antimicrobial susceptibility was tested by disk diffusion and broth microdilution methods.

Results

During the one-year period of surveillance from January 2017 to December 2017, a total of 9,130 (11.9%) isolates of target pathogens were recovered from urine specimens of 76,625 patients with suspected urinary tract infection (UTI). The rate of culture-positive was the highest in the < 1 age group (AG) (22.5%), stiffly decreased in the 5–<15 AG to 3.4%, and gradually increased with age up to 19.6% in the ≥ 85 AG. The mean occurrence of UTI per 10,000 patient-days for inpatients was 19.3 (range, 3.4–46.1) for E. coli and 4.0 (range, 1.5–7.3) for K. pneumoniae. Resistance rate for cefotaxime was higher than those for ceftazidime both in E. coli (31.3% vs. 10.3%) and K. pneumoniae isolates (39.0% vs. 29.8%). Resistance rate for ciprofloxacin in E. coli isolates was 40.9%, and that in K. pneumoniae isolates was 31.9%. Only 4.9% and 10.9% of E. coli and K. pneumoniae isolates exhibited resistance phenotype to cefoxitin, respectively. Ertapenem-resistance was more frequently identified in K. pneumoniae isolates (1.6%) than in E. coli isolates (0.1%). Multidrug-resistance (MDR) phenotype was identified in 61.4% of the E. coli and 44.8% of K. pneumoniae urine isolates.

Conclusion

Kor-GLASS generated well-curated surveillance data devoid of collection bias or isolate duplication. Cefoxitin was an alternative treatment to ciprofloxacin for urinary tract infections caused by Enterobacteriaceae. About one-half of urine isolates belonged to either MDR or XDR.

Disclosures

All authors: No reported disclosures.

P5298Influence of the changes in body fat on all-cause and cardiovascular mortality in a general population: a report from Ansan-Ansung cohort in the Korean genome environment study

Background

Paradoxical beneficial effects of obesity on all-cause and cardiovascular mortality have been reported in multiple cohort studies based on patients with cardiovascular disease as well as general populations. However, the association between the presence of obesity at baseline and the better survival rates could not be directly interpreted into the beneficial effect of gain in obesity or fatness on the mortality, which makes it difficult to provide any recommendation for the management of obesity. Therefore, we investigated the influence of the changes in body fat on all-cause and cardiovascular mortality in a general population.

Methods

A population-based cohort study has been conducted for 12 years (from 2001 to 2012). A total of 5,259 subjects in whom body compositions using a bio-impedance method were measured at least 2 times during the observational period were included. The causes of death was identified from the nation-wide database in KOSTAT. I20-I82 and R99 in the International Classification of Disease-10 codes were defined as a cardiovascular death. The subjects were evenly divided into 3 groups by the percentages of the changes in body fat (Δ%BF; decreased [Δ%BF <0.0%] vs. increased [Δ%BF 0.0–13.7%] vs. highly increased [Δ%BF ≥13.7%]). Inverse probability of treatment weighting was applied to balance the covariate differences among the groups.

Results

The age was 51.2±8.5 years and 51.6% was male. Median observation duration was 163 (the interquartile range: 157–168) months. The all-cause death and cardiovascular death occurred most frequently in the decreased Δ%BF group and least frequent in the highly increased Δ%BF group in both unweighted and weighted cohort. Multivariate Cox proportional hazard models showed that the risk of all-cause death was lower in the increased and highly increased Δ%BF groups (hazard ratio [HR] 0.61 [0.47–0.80] and 0.24 [0.17–0.34], respectively) and the risk of cardiovascular death was lower in the highly increased Δ%BF group (HR 0.20 [0.08–0.48]), compared to those in the decreased Δ%BF group after adjustment for all covariates including physical activities and the changes in muscle mass. The risk of all-cause death and cardiovascular death linearly decreased with increasing Δ%BF (HR 0.72 [0.67–0.77] and 0.70 [0.60–0.82], respectively).

Conclusion

The increase in body fat is associated with a lower risk of all-cause death and cardiovascular death in a middle-age general population, independently with physical activities and the changes in muscle mass.

P5665The independent effect of insulin resistance on incidence of atrial fibrillation in non-diabetics

Purpose

Patients with diabetes mellitus have an elevated risk of atrial fibrillation (AF). However, whether insulin resistance may elevate risk of AF incidence in non-diabetic is inconsistent. The aim of our study was to verify the association between insulin resistance and incidence of AF in non-diabetics.

Methods

We evaluated population-based cohorts embedded in the Korean Genome Epidemiology Study. Insulin resistance was expressed as Homeostasis Model Assessment for Insulin resistance (HOMA-IR). Baseline data including HOMA-IR and electrocardiography (ECG) were obtained at 2001. Subsequent biennial ECG was performed for identification of AF until 2016.

Results

Among the 8220 participants (46.8% male; median age 49 years), 25 participants had AF (0.3%) at baseline and 101 participants developed AF (1.2%) during follow up of 12 years. In multivariate Cox regression analysis, high HOMA-IR (≥1.4) was significantly associated with incident AF compared with low HOMA-IR (<1.40) (adjusted hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.3–3.0). In subgroup analysis, these association was consistent regardless of obesity (BMI<25; adjust HR 1.8, 95% CI 1.1–3.0, BMI≥25; adjust HR 2.3, 95% CI 1.3–4.0)

Subgroup analysis

Conclusion

Based on prospective cohort study, insulin resistance (HOMA-IR) was associated with AF independently of obesity in non-diabetics.

Streptococcus koreensis sp. nov., Isolated from Human Subgingival Dental Plaque of Periodontitis Lesion

A novel facultative anaerobic, Gram-stain-positive coccus, strain JS71^T, was isolated from the human subgingival dental plaque of a periodontitis lesion. Phylogenetic analysis based on the 16S ribosomal RNA gene (16S rDNA) revealed that the strain belonged to the genus Streptococcus. The 16S rDNA sequence had high similarity with Streptococcus rubneri DSM 26920^T (98.6%), Streptococcus parasanguinis ATCC 15912^T (98.5%), and Streptococcus australis CCUG 45919^T (98.3%). The genome of strain JS71^T was 2,009,592 bp in length. The DNA G+C content of the strain was 42.1 mol%. Average nucleotide identity values between strain JS71^T and S. rubneri DSM 26920^T, S. parasanguinis ATCC 15912^T, and S. australis CCUG 45919^T were 88.9%, 80.8%, and 92.4%, respectively. Genome-to-genome distance values between strain JS71^TS. rubneri DSM 26920^T, S. parasanguinis ATCC 15912^T, and S. australis CCUG 45919^T were 36.5% (34-39%), 26.3% (23.9-28.7%), and 48.0% (45.4-50.6%), respectively. The major fatty acids of the strain were C_16:0 (39.7%), C_{18:1 ω6c}/C_{18:1 ω7c} (15.5%), and C_18:0 (10.4%). Based on these results, strain JS71^T (= KCOM 2890^T = JCM 33454^T) should be a novel species of the genus Streptococcus, for which the name Streptococcus koreensis sp. nov. is proposed.

Risk factors of community-onset extended-spectrum β-lactamase-producing Klebsiella pneumoniae bacteraemia in South Korea using national health insurance claims data

BACKGROUND

Although it is essential to know the particular causes of antibiotic-resistant infections in the community, there is lack of evidence regarding risk factors for community-onset extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) bacteraemia in South Korea. As such, this study aimed to identify risk factors for community-onset ESBL-KP bacteraemia.

METHODS

From May 2016 to April 2017, patients with community-onset KP bloodstream infection (BSI) (n = 408) from six sentinel hospitals participating in the Global Antimicrobial Surveillance System in South Korea were included in this study. Risk factors of ESBL-KP BSI were assessed. Polymerase chain reaction and sequencing to identify genes encoding ESBLs and multi-locus sequence typing were performed.

RESULTS

Of the 408 patients with community-onset KP BSI, 70 (17%) had ESBL-KP BSI. Admission to a long-term-care hospital within the previous 3 months [odds ratio (OR) 5.7, 95% confidence interval (CI) 2.1-15.6; P = 0.001], previous use of trimethoprim/sulfamethoxazole (TMP/SMT; OR 11.5, 95% CI 2.7-48.6; P = 0.001) or extended-spectrum cephalosporin (OR 2.2, 95% CI 1.2-3.9; P = 0.01), and previous use of a urinary catheter (OR 2.3, 95% CI 1.1-4.5; P = 0.02) were independent risk factors for community-onset ESBL-KP BSI. ESBL-KP isolates most frequently carried the CTX-M-1 group ESBL (74%, n = 52). The most prevalent sequence type (ST) among the ESBL-KP isolates was ST48 (14%, n = 10). Among non-ESBL-KP isolates, ST23 was most prevalent (21%, n = 70).

CONCLUSION

Previous admission to a long-term-care hospital, use of a urinary catheter and use of TMP/SMT or extended-spectrum cephalosporin within the previous 3 months were identified as risk factors for community-onset ESBL-KP BSI. Strict antibiotic stewardship and infection control measures are needed for long-term-care hospitals.