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AbstractObjective:We evaluated the adequacy of microbiological tests in patients withholding or withdrawing life-sustaining treatment (WLST) at the end stage of life.Setting:The study was conducted at 2 tertiary-care referral hospitals in Daegu, Republic of Korea.Design:Retrospective cross-sectional study.Methods:Demographic findings, clinical and epidemiological characteristics, statistics of microbiological tests, and microbial species isolated from patients within 2 weeks before death were collected in 2 tertiary-care referral hospitals from January to December 2018. We also reviewed the antimicrobial treatment that was given within 3 days of microbiological testing in patients on WLST.Results:Of the 1,187 hospitalized patients included, 905 patients (76.2%) had WLST. The number of tests per 1,000 patient days was higher after WLST than before WLST (242.0 vs 202.4). Among the category of microbiological tests, blood cultures were performed most frequently, and their numbers per 1,000 patient days before and after WLST were 95.9 and 99.0, respectively. The positive rates of blood culture before and after WLST were 17.2% and 18.0%, respectively. Candidaspp. were the most common microbiological species in sputum (17.4%) and urine (48.2%), and Acinetobacterspp. were the most common in blood culture (17.3%). After WLST determination, 70.5% of microbiological tests did not lead to a change in antibiotic use.Conclusions:Many unnecessary microbiological tests are being performed in patients with WLST within 2 weeks of death. Microbiological testing should be performed carefully and in accordance with the patient’s treatment goals.

Introduction: Regdanvimab, a monoclonal antibody pharmaceutical, is the first Korean drug approved for treating coronavirus disease 2019 (COVID-19). We analyzed the therapeutic efficacy of regdanvimab in patients with the COVID-19 delta variant infection. Methods: We retrospectively reviewed the electronic medical records of patients hospitalized at two Korean tertiary COVID-19 hospitals with COVID-19 delta variant infection between May 26, 2021, and January 30, 2022. To analyze the therapeutic efficacy of regdanvimab, the patients were divided into regdanvimab and non-regdanvimab groups and were 1:1 propensity-score (PS)-matched on age, severity at admission, and COVID-19 vaccination history. Results: Of 492 patients, 262 (53.3%) and 230 (46.7%) were in the regdanvimab and non-regdanvimab groups, respectively. After PS matching the groups on age, severity at admission, and COVID-19 vaccination history, each group comprised 189 patients. The 30-day hospital mortality rates (0.0% vs. 1.6%, p= 0.030), proportions of patients with exacerbated conditions to severe/critical/died (9.5% vs. 16.4%, p= 0.047), proportions who received oxygen therapy because of pneumonia exacerbation (7.4% vs. 16.4%, p= 0.007), and proportions with a daily National Early Warning Score ≥ 5 from hospital day 2 were significantly lower in the regdanvimab group. Conclusions: We showed that regdanvimab reduced the exacerbation rates of conditions and mortality in patients with the COVID-19 delta variant infection. Thus, it is recommended to streamline the drug approval system during epidemics of new variant viruses to improve the availability and usage of therapeutics for patients. To facilitate this, relevant institutional support is required.

The interferon‐γ(IFN‐γ) release assay (IGRA) is widely used to diagnose tuberculosis (TB) caused by Mycobacterium tuberculosis(Mtb). However, indeterminate IGRA results due to “high Nil” or “low PHA” responses limit its clinical utility. We developed a novel assay using CD69 flow cytometry (FC) to complement IGRA. CD69 FC measures the surface CD69 expression on T cells prior to centrifugation to harvest the plasma for IGRA. T cell responses against Mtb antigen 1 (Ag1) or Ag2 were measured using three‐color FC (CD3, CD4, and CD69) in TB (n = 140) and non‐TB groups (n = 117). The cutoff values of Δ%CD69brightcells (stimulated minus unstimulated) for CD4+and CD4−T cells were established based on healthy individuals (n = 63). The assay performances of CD69 FC and IGRA were compared. In subjects with determinate IGRA results (“positive” or “negative”; n = 216), the diagnostic accuracies of CD69 FC (90.3%) and IGRA (87.0%) were not significantly different (p= 0.31). For indeterminate IGRA results (n = 40), CD69 FC attained a diagnostic accuracy of 92.5%. The CD4+/CD4−ratio within CD69brightT cells measured by CD69 FC was significantly higher (p< 0.05) in the active TB group (6.39 ± 132.05; n = 72) than in other CD69 FC‐positive subjects (2.84 ± 15.36; n = 63) (p< 0.05), whereas CD8 responses expected by IGRA (difference of IFN‐γlevels between Mtb Ag tubes) did not differ significantly (0.00 ± 9.18 and 0.00 ± 4.25, respectively, IU/ml; p= 0.58). We demonstrated the potential of CD69 FC as a simple, rapid assay for clarifying indeterminate IGRA results and identifying active TB. With further improvements, CD69 FC may complement the IGRA to enhance TB risk stratification in the routine diagnostic workup.

AbstractRapid diagnostic testing (RDT) can provide prompt, accurate identification of infectious organisms and be a key component of antimicrobial stewardship (AMS) programs. However, their use is less widespread in Asia Pacific than western countries. Cost can be prohibitive, particularly in less resource-replete settings. A selective approach is required, possibly focusing on the initiation of antimicrobials, for differentiating bacterial versus viral infections and identifying locally relevant tropical diseases. Across Asia Pacific, more data are needed on RDT use within AMS, focusing on the impact on antimicrobial usage, patient morbidity and mortality, and cost effectiveness. Moreover, in the absence of formal guidelines, regional consensus statements to guide clinical practice are warranted. These will provide a regionally relevant definition for RDT; greater consensus on its role in managing infections; advice on implementation and overcoming barriers; and guidance on optimizing human resource capacity. By addressing these issues, the outcomes of AMS programs should improve.

AbstractObjectives:We calculated the human resources required for an antimicrobial stewardship program (ASP) in Korean hospitals.Design:Multicenter retrospective study.Setting:Eight Korean hospitals ranging in size from 295 to 1,337 beds.Methods:The time required for performing ASP activities for all hospitalized patients under antibiotic therapy was estimated and converted into hours per week. The actual time spent on patient reviews of each ASP activity was measured with a small number of cases, then the total time was estimated by applying the determined times to a larger number of cases. Full-time equivalents (FTEs) were measured according to labor laws in Korea (52 hours per week).Results:In total, 225 cases were reviewed to measure time spent on patient reviews. The median time spent per patient review for ASP activities ranged from 10 to 16 minutes. The total time spent on the review for all hospitalized patients was estimated using the observed number of ASP activities for 1,534 patients who underwent antibiotic therapy on surveillance days. The most commonly observed ASP activity was ‘review of surgical prophylactic antibiotics’ (32.7%), followed by ‘appropriate antibiotics recommendations for patients with suspected infection without a proven site of infection but without causative pathogens’ (28.6%). The personnel requirement was calculated as 1.20 FTEs (interquartile range [IQR], 1.02–1.38) per 100 beds and 2.28 FTEs (IQR, 1.93–2.62) per 100 patients who underwent antibiotic therapy, respectively.Conclusion:The estimated time required for human resources performing extensive ASP activities on all hospitalized patients undergoing antibiotic therapy in Korean hospitals was ~1.20 FTEs (IQR, 1.02–1.38) per 100 beds.

ABSTRACTTwo antigenically distinct influenza B lineage viruses (Yamagata/Victoria) have been co-circulating globally since the mid-1980s. The quadrivalent influenza vaccine (QIV) may provide better protection against unpredictable B strains. We conducted a randomized, double-blind, phase III trial to evaluate the immunogenicity and safety of an egg-based inactivated, split-virion QIV (GC3110A). Subjects aged ≥ 19 years were randomized 2:1:1 to be vaccinated with QIV- GC3110A, trivalent influenza vaccine (TIV) containing the Yamagata lineage strain (TIV-Yamagata), or TIV containing the Victoria lineage strain (TIV-Victoria). Hemagglutination inhibition assays were performed 21 days post-vaccination. Solicited/unsolicited adverse events (AEs) were assessed within 21 days after vaccination, while serious AEs were reported up to six months after vaccination. A total of 1,299 were randomized to receive QIV-GC3110A (648 subjects), TIV-Yamagata (325 subjects), or TIV-Victoria (326 subjects). Compared to the TIVs, the QIV-GC3110A met the non-inferiority criteria for all four subtype/lineage strains with respect to the geometric mean titer (GMT) ratio and the difference of seroconversion rate. The safety profiles of QIV-GC3110A were consistent with those of TIV. In conclusion, QIV-GC3110A is safe, immunogenic, and comparable to strain-matched TIV.

Effective two-drug regimens could decrease long-term drug exposure and toxicity with HIV-1 antiretroviral therapy (ART). We therefore aimed to evaluate the efficacy and safety of a two-drug regimen compared with a three-drug regimen for the treatment of HIV-1 infection in ART-naive adults.

Genes encoding ciprofloxacin resistance in enterococci in animals may be transferred to bacteria in the animal gut and to zoonotic bacteria where they could pose a human health hazard. The objective of this study was to characterize antimicrobial resistance in high-level ciprofloxacin-resistant (HLCR) Enterococcus faecalisand Enterococcus faeciumisolated from retail chicken meat. A total of 345 enterococci (335 E. faecalisand 10 E. faecium) were isolated from 200 chicken meat samples. Of these, 85 E. faecalisisolates and 1 E. faeciumisolate were confirmed as HLCR enterococci. All 86 HLCR enterococci displayed gyrA-parCpoint mutations consisting of S83I-S80I (94.2%, 81 isolates), S83F-S80I (2.3%, 2 isolates), S83Y-S80I (2.3%, 2 isolates), and S83Y-S80F (1.2%, 1 isolate). Sixty-one (72.9%) of the 86 HLCR enterococci showed multidrug resistance to three to six classes of antimicrobial agents. Multilocus sequence typing revealed that E. faecalishad 17 different sequence types (ST) and E. faeciumhad 1 different ST, with ST256 observed most often (44 isolates, 51.8%). Although these results cannot exclude the possibility that pathotypes of enterococci isolated from chicken might represent transmission to or from humans, the foodborne HLCR E. faecalisindicated that the food chain is a potential route of enterococcal infection in humans.

ABSTRACTBackground: The influenza B virus has two lineages; Yamagata and Victoria. The two lineages are antigenically distinct and it is difficult to expect cross-protection between the lineages. Actually, the mismatch between circulating influenza B viruses and vaccine strains has been occurred frequently. The cell-culture system for the production of influenza vaccine can contribute to improve vaccine strain selection and expand vaccine supplies. We investigated the immunogenicity and safety of cell culture-derived quadrivalent inactivated influenza vaccine (NBP607-QIV) in adults and elderly subjects.Methods: A randomized controlled phase III trial was undertaken in 10 university hospitals in the Republic of Korea (Clinical trial Number—NCT02467842). Adults (aged 19–59 years) and elderly subjects (aged ≥60 years) were randomly assigned in a 2:1:1 ratio to NBP607-QIV versus cell culture-based trivalent inactivated influenza vaccine-Yamagata (NBP607-Y) and cell culture-based trivalent inactivated influenza vaccine-Victoria (NBP607-V). Immunogenicity was assessed 3 weeks after vaccination by hemagglutination inhibition assay. Safety was assessed for 6 months post-vaccination: solicited adverse events (AEs) for 7 days, unsolicited AEs for 21 days and serious adverse events (SAEs) for 6 months. AEs were sub-classified as adverse drug reactions (ADRs) according to the causality.Results: A total of 1,503 participants were randomly assigned to NBP607-QIV (n = 752), NBP607-Y (n = 373) and NBP607-V (n = 378). The seroconversion rates of NBP607-QIV were 52.4%, 51.2%, 43.7% and 55.8% against A/H1N1, A/H3N2, B/Yamagata and B/Victoria, respectively. Non-inferiority against shared strains and superiority against alternate-lineage B strains were demonstrated for NBP607-QIV vs. NBP607-Y and NBP607-V. A total of 730 reactions occurred in 324 (43.1%) subjects of NBP607-QIV group. Majority of ADRs was solicited (99.2%) and mild (90.3%) in intensity. In adults (aged 19–59 years), solicited local AEs were slightly more frequent in NBP607-QIV group than NBP607-Y or NBP607-V group (40.9%, 33.4% and 32.5%, respectively). One SAE was observed among NBP607-QIV group, which was considered to be unrelated to the study vaccine within 3 weeks of vaccination and no vaccine-related SAEs were reported up to 6 months after vaccination.Conclusions: NBP607-QIV is a safe, well-tolerated and immunogenic influenza vaccine in Korean adults and elderly subjects.

ABSTRACTSome proportion of type A blaZgene-positive methicillin-susceptible Staphylococcus aureusstrains exhibit the cefazolin inoculum effect (CIE). The type A blaZgene was divided into two groups by single nucleotide polymorphisms (SNPs) at Ser226Pro and Cys229Tyr. The median cefazolin MICs at a high inoculum concentration were 5.69 μg/ml for the Ser-Cys group and 40.32 μg/ml for the Pro-Tyr group (P= 0.01). The SNPs at codons 226 and 229 in the amino acid sequence encoded by the blaZgene were closely associated with the CIE.

ABSTRACTPneumonia and acute exacerbation of chronic illness are leading causes of influenza-related hospitalization. Therefore, influenza and pneumococcal vaccinations are strongly recommended for adults with comorbidities. Using a hospital-based influenza surveillance system, we performed a multicenter, prospective cohort study of patients visiting emergency rooms with influenza-like illness (ILI) during the influenza epidemic period in 2013 to 2014. Patients aged =19 years were enrolled, and clinical data were collected. Multivariate analyses were performed to estimate the effectiveness of influenza and pneumococcal vaccination in preventing pneumonia development and hospitalization. During study periods, 2,262 patients with ILI were registered. Among 2,217 patients with available vaccination records, 31.9% (707 patients) and 9.7% (216 patients) had received influenza and pneumococcal vaccines, respectively. Among patients who had been administered a pneumococcal vaccine, 94.4% had received the 23-valent polysaccharide vaccine (PPV23). The adjusted rates of effectiveness of the influenza vaccine for preventing pneumonia development and hospitalization were 64.0% (95% confidence interval [CI] = 29% to 81%) and 35.0% (95% CI = 12% to 52%), respectively. Pneumococcal vaccination did not reduce pneumonia development or hospitalization. In conclusion, influenza rather than PPV23 vaccination may reduce pneumonia development and hospitalization in patients with preceding ILI.

ABSTRACTThe purpose of this study was to compare the clinical efficacy and safety of vancomycin to those of teicoplanin for the treatment of adult patients with health care-associated methicillin-resistant Staphylococcus aureus(HA-MRSA) bacteremia. A multicenter observational study was prospectively conducted in 15 teaching hospitals in Korea between February 2010 and July 2011. Adult patients (≥18 years old) with HA-MRSA bacteremia who were initially treated with vancomycin (VAN) (n= 134) or teicoplanin (TEC) (n= 56) were enrolled. Clinical and microbiological responses and drug-related adverse events were compared between the two treatment groups using univariate and multivariate logistic regression analyses. The vancomycin and teicoplanin MICs were determined by Etest. The MRSA-related mortality, duration of fever, and duration of MRSA bacteremia in the treatment groups were not significantly different. There was no significant difference in the occurrence of drug-related adverse events. Among the 190 MRSA isolates, the VAN MICs ranged from 0.5 to 2 μg/ml (MIC50and MIC90, 1.5 μg/ml), and the TEC MIC ranged from 0.5 to 8 μg/ml (MIC50, 3 μg/ml; MIC90, 6 μg/ml). In multivariate analyses, the antibiotic type (vancomycin or teicoplanin) was not associated with treatment outcomes. This study indicates that teicoplanin is an effective and safe alternative to vancomycin for the treatment of HA-MRSA bacteremia.

ABSTRACTCandidaspecies are the leading causes of invasive fungal infection among hospitalized patients and are responsible for major economic burdens. The goals of this study were to estimate the costs directly associated with the treatment of candidemia and factors associated with increased costs, as well as the impact of first-line antifungal agents on the outcomes and costs. A retrospective study was conducted in a sample of 199 patients from four university-affiliated tertiary care hospitals in Korea over 1 year. Only costs attributable to the treatment of candidemia were estimated by reviewing resource utilization during treatment. Risk factors for increased costs, treatment outcome, and hospital length of stay (LOS) were analyzed. Approximately 65% of the patients were treated with fluconazole, and 28% were treated with conventional amphotericin B. The overall treatment success rate was 52.8%, and the 30-day mortality rate was 47.9%. Hematologic malignancy, need for mechanical ventilation, and treatment failure of first-line antifungal agents were independent risk factors for mortality. The mean total cost for the treatment of candidemia was $4,743 per patient. Intensive care unit stay at candidemia onset and antifungal switch to second-line agents were independent risk factors for increased costs. The LOS was also significantly longer in patients who switched antifungal agents to second-line drugs. Antifungal switch to second-line agents for any reasons was the only modifiable risk factor of increased costs and LOS. Choosing an appropriate first-line antifungal agent is crucial for better outcomes and reduced hospital costs of candidemia.

ABSTRACTThis multinational study from Asia revealed that reduced susceptibility to ciprofloxacin (MIC, 0.125 to 1 μg/ml) in nontyphoid Salmonellaisolates was common in Taiwan (48.1%) and Thailand (46.2%) and in S. entericaserotype Choleraesuis (68.8%) and S. Virchow (75.0%) from all countries. Reduced susceptibility to ceftriaxone (MIC, 2 to 8 μg/ml) remained uncommon in Asia, except in Taiwan (38.0%) or in S. Typhimurium (25.0%) from all countries.

The electrochemical properties of LiFePO4 as a cathode of lithium ion batteries considerably depend on a particle size of LiFePO4 and a condition of carbon coating. In this study, LiFePO4 powders were prepared using ultrasonic spray pyrolysis method, and then LiFePO4/C composites were made by infiltrating sucrose solution into LiFePO4 powders, drying, high-energy milling and annealing. The effects of high-energy milling were analyzed by comparing with electrochemical properties of powders synthesized without high-energy milling. It was found that the milling process drastically reduced the particle size of synthesized powders and electrical conductivity, and improved discharge capacity, cycle stability and rate performance.

The ultrasonic spray pyrolysis method and proper heat treatments were applied in order to synthesize La0.8Sr0.2CrO3 (LSC) which is one of promising materials for separator in soild oxide fuel cell in this study. LSC powders that were sprayed at 800oC, heat-treated at 900oC for 5 hrs, ball-milled and finally heat-treated again at 1200oC for 20 hrs showed the average diameter of 0.3 *m and narrow size distribution to find particles above 0.5 *m hardly. In addition, the synthesizing temperature of LSC powders in ultrasonic spray pyrolysis method was 100[removed info] lower than conventional ball milling and drying method. Therefore the proper combination of heat treatment and milling process after spray pyrolysis was found to be very critical in synthesizing fine and uniform LSC powders. Finally, the sintering properties of these LSC powders were analyzed and compared with those of conventional ones.

Objectives: To analyse the risk factors for nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infections caused by different clonal types.Methods: A total of 134 non-duplicate nosocomial MRSA isolates were analysed for clonal types by molecular typing techniques. The medical records of 90 patients who had documented MRSA infection were evaluated retrospectively.Results: Two predominant MRSA clones of sequence types (STs) ST239 (n = 75) and ST5 (n = 39) accounted for 85% of the isolates. Management of patients in the departments of orthopaedic surgery, neurosurgery and plastic surgery was identified as a risk factor for infection with MRSA of ST239, while the presence of intravascular catheters was a risk factor for infection with ST5. Pulmonary infection was significantly higher in the patients infected with ST239 strains than in the patients infected with ST5 strains (P < 0.05). The overall mean duration of antimicrobial therapy for the patients with ST239 infection was significantly more than that for the patients with ST5 infection (P < 0.05).Conclusions: ST239 and ST5 were the predominant MRSA clones in the study hospital. Risk factors were significantly different between ST239 and ST5 strains. The results of this study will be of use in designing larger prospective epidemiological studies for MRSA infection based on clonal types.

ABSTRACTA total of 188 nonduplicate methicillin-resistant Staphylococcus aureus(MRSA) isolates obtained between 2001 and 2004 in a university hospital in Daegu, Korea, were analyzed for their clonal types by molecular typing techniques, including multilocus sequence typing, spaAtyping, staphylococcal chromosomal cassette mec(SCCmec) typing, and pulsed-field gel electrophoresis (PFGE). They were examined for their antimicrobial susceptibilities. The majority (87%) of MRSA isolates belonged to sequence type 239 (ST239; n= 100; 53%) and ST5 (n= 63, 34%) on the basis of sequence typing. MRSA isolates belonging to ST239 were genotypically homogeneous, while those belonging to ST5 showed variations in spaAtype, SCCmectype, and PFGE patterns. The rates of resistance of the MRSA isolates belonging to ST239 to trimethoprim, sulfamethoxazole, tobramycin, gentamicin, erythromycin, and tetracycline were significantly higher than those of the isolates belonging to ST5 (P< 0.05). This study demonstrated that the ST239 clone, while rarely detected in Korea, was prevalent and that the antimicrobial susceptibility of the ST239 clone was significantly different from that of the ST5 clone.

pbp2b gene alterations were analyzed in 102 clinical isolates of Streptococcus pneumoniae (30 penicillin susceptible, 23 intermediate, and 49 resistant) from Korea. On the basis of PBP2B amino acid sequences, penicillin-nonsusceptible isolates of S. pneumoniae belonged to six groups, and 76% of the isolates in groups I to IV showed the same divergent block of amino acid alterations. Thirteen isolates (group II) also possessed a divergent block that was identical to that of Streptococcus oralis. The pbp2b genes of most Korean isolates showed novel mosaic mutations due to horizontal gene transfer. The Thr252 --> Ala substitution, previously thought to be associated only with penicillin-nonsusceptible strains, was also found in three penicillin-susceptible strains. On the basis of their pbp2b nucleotide sequences, all penicillin-nonsusceptible isolates can be detected by multiplex PCR, which can be used as a novel method for detection of antibiotic-resistant pneumococcal strains in clinical specimens.

ABSTRACTpbp2bgene alterations were analyzed in 102 clinical isolates of Streptococcus pneumoniae(30 penicillin susceptible, 23 intermediate, and 49 resistant) from Korea. On the basis of PBP2B amino acid sequences, penicillin-nonsusceptible isolates of S. pneumoniaebelonged to six groups, and 76% of the isolates in groups I to IV showed the same divergent block of amino acid alterations. Thirteen isolates (group II) also possessed a divergent block that was identical to that of Streptococcus oralis. The pbp2bgenes of most Korean isolates showed novel mosaic mutations due to horizontal gene transfer. The Thr252?Ala substitution, previously thought to be associated only with penicillin-nonsusceptible strains, was also found in three penicillin-susceptible strains. On the basis of their pbp2bnucleotide sequences, all penicillin-nonsusceptible isolates can be detected by multiplex PCR, which can be used as a novel method for detection of antibiotic-resistant pneumococcal strains in clinical specimens.

ABSTRACTPulsed-field gel electrophoresis, ribotyping, and fingerprinting analysis of 22 invasive isolates of multidrug-resistant (MDR) pneumococci from Korea showed that 59 to 82% were genetically related. DNA sequencing of the PBP 2B gene showed relatively uniform alterations in nucleotides (5.4 to 7.8%) and amino acids (3.0 to 4.3%), while Asn-276?Lys, Arg-285?Cys and Ser-305?Phe substitutions were unique to Korean MDR strains, suggesting the spread of a few epidemic clones of resistant pneumococci within Korea.

The detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in upper and lower respiratory specimens and coinfection with other respiratory pathogens in patients with coronavirus disease 2019 (COVID-19) was investigated. Study subjects (N = 342) were retrospectively enrolled after being confirmed as SARS-CoV-2 positive, and their nasopharyngeal swab (NPS), oropharyngeal swab (OPS), and sputum specimens were restored for SARS-CoV-2 retesting and respiratory pathogen detection. The majority of the subjects (96.5%, N = 330) were confirmed as SARS-CoV-2 positive using NPS/OPS specimens. Among the COVID-19 patients (N = 342), 7.9% (N = 27) and 0.9% (N = 3) were coinfected with respiratory viruses and Mycoplasma pneumoniae, respectively, yielding an 8.8% (N = 30) overall respiratory pathogen coinfection rate. Of the respiratory virus coinfection cases (N = 27), 92.6% (N = 25) were coinfected with a single respiratory virus and 7.4% (N = 2) with two viruses (metapneumovirus/adenovirus and rhinovirus/bocavirus). No triple coinfections of other respiratory viruses or bacteria with SARS-CoV-2 were detected. Respiratory viruses coinfected in the patients with COVID-19 were as follows: rhinovirus (N = 7, 2.1%), respiratory syncytial virus A and B (N = 6, 1.8%), non-SARS-CoV-2 coronaviruses (229E, NL63, and OC43, N = 5, 1.5%), metapneumovirus (N = 4, 1.2%), influenza A (N = 3, 0.9%), adenovirus (N = 3, 0.9%), and bocavirus (N = 1, 0.3%). In conclusion, the diagnostic value of utilizing NPS/OPS specimens is excellent, and, as the first report in Korea, coinfection with respiratory pathogens was detected at a rate of 8.8% in patients with COVID-19.

ABSTRACTSeventy-three liver abscess isolates of serotype K1 Klebsiella pneumoniaefrom a nationwide collection in Korea were genotypically characterized using pulsed-field gel electrophoresis and multilocus sequence typing. We found that serotype K1 K. pneumoniaestrains that caused liver abscesses in Korea were genotypically related and that most were sequence type 23.

ABSTRACTWe tested the in vitro susceptibilities of 603 enterococcal isolates from eight tertiary-care hospitals in Korea. The quinupristin-dalfopristin resistance rate in Enterococcus faeciumwas very high (25 isolates, 10.0%). It was suggested that both clonal spread and the sporadic emergence of quinupristin-dalfopristin-resistant isolates may explain the high prevalence of quinupristin-dalfopristin resistance in Korea.

ABSTRACTNinety-six methicillin-resistant Staphylococcus aureus(MRSA) isolates from eight Korean hospitals were analyzed by multilocus sequence typing, SCCmectyping, and spatyping. The predominant genotype was ST5-MRSA-II of clonal complex 5, which was found in 36 isolates from six hospitals, but ST239-MRSA-III was also common. Overall, results showed a notable genotypic diversity of MRSA strains circulating in Korean hospitals.

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