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Background: Sequence type 72 (ST72) is the predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) genotype in Korea. With an increasing prevalence of the ST72 S. aureus lineage, regardless of methicillin resistance, it is crucial to understand the clinical and microbiological characteristics of ST72 methicillin-susceptible S. aureus (MSSA) as well as ST72 MRSA. Materials and Methods: In this retrospective cohort study, data from patients with S. aureus bacteremia (SAB) who were admitted to a tertiary hospital in Korea from March 2007 to December 2018 were collected. Multilocus sequence typing was used to identify ST72 isolates. The clinical and microbiological characteristics of ST72 MSSA were compared with those of ST72 MRSA among patients infected with SAB. Results: Among the 442 SAB patients with ST72, 157 (35.5%) were infected with MSSA and 285 (64.5%) were infected with MRSA. There was a significant increase in the proportion of ST72 MSSA in both the community and hospital settings. Compared to ST72 MRSA, ST72 MSSA isolates were less likely to have multidrug resistance. The main infection foci, infection severity, and duration of bacteremia did not differ significantly between the two groups. The 90-day recurrence rate was significantly lower in the MSSA group (2.5% vs. 8.4%, P=0.03), while the 90-day mortality rate was comparable (28.0% vs. 23.9%, P=0.40). Conclusion: ST72 MSSA had similar clinical features as ST72 MRSA in terms of infection site, severity, and 90-day mortality. Despite exhibiting lower levels of antibiotic resistance, ST72 MSSA has increased in the hospital environment concurrently with ST72 MRSA. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus (RSV) constitutes a significant cause of respiratory illness and mortality among older adults, a demographic that is expanding with considerable impact on healthcare systems worldwide. The actual burden of RSV in this population may still be underestimated, owing to factors such as low awareness and suboptimal diagnostic sensitivity in adults, the lack of robust RSV surveillance systems, and the infrequent use of diagnostic testing. Recent advancements in respiratory virus detection have spurred further exploration into appropriate preventive and therapeutic strategies. The recent approval of two vaccines highlights the critical need for the precise estimation of the RSV disease burden to optimize the effectiveness and cost-efficiency of immunization programs. This narrative review aimed to summarize the existing knowledge of the RSV burden in adults with a particular focus on older adults, incorporating data from Korea. Overall, current estimates indicate that the annual RSV attack rate in the general adult population ranges from 1 - 7%, increasing to approximately 4 - 10% among elderly and high-risk groups. The in-hospital mortality rate can be estimated to be around 7 - 10%, rising up to 40% among intensive care unit-admitted patients. To elucidate RSV’s disease burden, further continuing research, including population-based studies, is necessary. [ABSTRACT FROM AUTHOR]

Background: Sporadic measles outbreaks have continued to occur in Korea, mainly in adults in their 20s and 30s, most notably in 2014 and 2019. We here evaluated the possible causes of a low seroprevalance of measles by testing young healthcare workers (HCWs). Materials and Methods: This study was conducted in a 2,743-bed tertiary-care hospital in Seoul between 2020 and 2021. We performed a measles antibody test (chemiluminescence immunoassay), measured the IgM/IgG index ratio, and conducted an avidity test at 1-month after Measles-Mumps-Rubella (MMR) vaccination in HCWs who had been seronegative for measles. Measles vaccination histories were obtained from the national vaccine registry. Results: Of the 3,173 HCWs newly employed in our hospital during the study period, 54 with a negative measles IgG at commencement were enrolled. Thirty six (67%) of these subjects were female, and the median age was 25 years (interquartile range [IQR]: 24 - 27). Fourty nine (91%) showed seroconversion at 1 month after the first vaccination. Of these individuals, 38 received both measles IgM and IgG test, and all had an IgM/IgG index <1. Of the 49 seroconverters, all HCWs showed a high avidity index. According to the national immunization registry, 45 (83%) received at least 2 doses of an MMR vaccination. Conclusion: Secondary vaccine failure may underlie vaccine failure in young Korean adults. HCWs born after 1985 with a negative measles antibody may need only a single dose booster vaccination rather than a 2-dose vaccination regimen. [ABSTRACT FROM AUTHOR]

배경: We aimed to identify which streptococcal species are closely associated with infective endocarditis (IE) and whether streptococcal species affect mortality in streptococcal IE. 방법: We performed a retrospective cohort study of all patients with streptococcal bloodstream infections (BSI) from 2010 to 2020 in a tertiary hospital in South Korea. We collected echocardiographic results within one month from BSI and compared clinical characteristics of patients with streptococcal BSI according to the diagnosis of IE. We performed multivariable analysis to evaluate risk of IE according to the species in streptococcal BSI and to identify risk factors for mortality in streptococcal IE. 결과: A total of 2737 patients were identified during the study period; 1177 (43%) patients performed echocardiography within one month from BSI, and 174 (6%) were diagnosed with IE. The highest IE prevalence was found with Streptococcus mutans (33% [9/27]) followed by S. sanguinis (31% [20/64]), S. gordonii (23% [5/22]), S. gallolyticus (16% [12/77]), and S. oralis (12% [14/115]) (Figure). In multivariable analysis, previous IE, high-grade BSI, native valve disease, prosthetic valve disease, congenital heart disease, and community-onset BSI were independent risk factors for IE. After adjusting for these risk factors, S. pneumoniae (adjusted OR [aOR] 0.23; 95% confidence interval [CI] 0.08-0.54), S. constellatus (aOR 0.37; 95% CI 0.12-0.88), S. sanguinis (aOR 7.75; 95% CI 3.64-16.00), S. gallolyticus (aOR 2.57; 95% CI 1.12-5.43), and S. mutans (aOR 5.50; 95% CI 1.83-15.70) were significantly associated with IE. Age, community-onset BSI, ischemic heart disease, and chronic kidney disease were independent risk factors for mortality in streptococcal IE. Streptococcal species did not affect mortality. 결론: Our study suggests significant differences in the prevalence of IE in streptococcal BSI according to the species, although species did not affect mortality in streptococcal IE. [ABSTRACT FROM AUTHOR]

배경: The sequence type 72 (ST72) is the predominant community-associated methicillin-resistant Staphylococcus aureus (MRSA) genotype in South Korea, replacing hospital clones as well as the community. During this change, we assessed the clinical characteristics of methicillin-susceptible and methicillin-resistant ST72 isolates causing bacteremia for better understanding of ST72 S. aureus in South Korea. 방법: We retrospectively collected data on patients with S. aureus bacteremia (SAB) who were admitted at a tertiary hospital in South Korea between March 2007 and December 2018. The ST72 isolates were identified by multilocus sequence typing (MLST). The clinical characteristics and outcomes of patients with methicillin-susceptible ST72 and those with methicillin-resistant ST72 were compared. 결과: A total 442 patients with ST72 SAB were identified, of which 157 (35.5%) were infected with methicillin-susceptible S. aureus (MSSA) and 285 (64.5%) were infected with MRSA. Community-onset infections were higher in the MSSA group compared to the MRSA group (20.4% vs. 10.2%, p=0.004), but the majority of infections occurred in healthcare-associated settings in both groups. MRSA isolates were likely to have multi-drug resistance and higher vancomycin MIC relative to the MSSA isolates. The main infection foci, infection severity, and bacteremic duration were not significantly different between the two groups. The 90-day SAB relapse was more common in the MRSA group than MSSA group (4.9% vs. 0.6%, P=0.04), while the 90-day mortality was comparable between the two groups (23.9% vs. 28.0%, P=0.39). 결론: In this study, a significant number of ST72 MSSA and ST72 MRSA infection occurred in hospital and healthcare settings. The 90-day recurrence rate was higher in methicillin-resistant ST72 infection than in methicillin-susceptible ST72 infection but there was no significant differences in type of main infection focus, presence of persistent bacteremia, and 90-day mortality. [ABSTRACT FROM AUTHOR]

배경: There are limited data comparing the transmission rates and kinetics of viable virus shedding of the omicron variant to those of the delta variant. We compared these rates in hospitalized patients infected with delta and omicron variants. 방법: We prospectively enrolled adult patients with COVID-19 admitted to a tertiary care hospital in South Korea between September 2021 and May 2022. Secondary attack rates were calculated by epidemiologic investigation, and daily saliva samples were collected to evaluate viral shedding kinetics. Genomic and subgenomic SARS-CoV-2 RNA was measured by PCR, and virus culture was performed from daily saliva samples. 결과: A total of 88 patients with COVID-19 who agreed to daily sampling and were interviewed, were included. Of the 88 patients, 48 (59%) were infected with delta, and 34 (41%) with omicron ; a further five patients gave undetectable or inconclusive RNA PCR results and one was suspected of being co-infected with both variants. The baseline characteristics of the two groups were comparable except that fewer of the delta patients had been vaccinated, and the delta patients had more severe disease. The latter also had a higher secondary attack rate (31% [38/124]) vs. 7% [34/456], p<0.001 : Table 1). Multivariable analysis revealed that moderate-to-critical disease severity (HR 1.96), immunocompromised status (HR 2.17), fully- or 1st booster-vaccinated status (HR 0.49), and omicron infection (HR 0.44) were independently associated with prolonged viable virus shedding (Table 2). 결론: Patients with omicron infections had higher transmission rates but shorter periods of transmissible virus shedding than those with delta infections. [ABSTRACT FROM AUTHOR]

Background: Pyomyositis (PM) is a serious soft tissue infection and despite its clinical importance, previous studies have not been able to fully determine the clinical characteristics and microbial epidemiology of PM in Korea, which we therefore aimed to investigate. Materials and Methods: We retrospectively identified 140 adult patients diagnosed with PM from 13 general hospitals between January 2012 and December 2015. We analyzed the clinical and microbial characteristics of community-onset PM and compared them with communityacquired (CA) and healthcare-associated (HCA) PM. Results: One hundred eleven organisms were isolated from 96 (68.6%) patients with PM. Staphylococcus aureus (38 patients) was the most common pathogen, followed by streptococci (24 patients), and enteric Gram-negative organisms (27 patients). Methicillin-resistant S. aureus (MRSA) was identified in four (2.9%) patients and in-hospital mortality reached 8.6% (12/140). Enterococci isolates were identified in the HCA PM subgroup only The proportion of MRSA isolates was not comparable between CA and HCA PM subgroups. In the 83 patients with PM infected by monomicrobial pathogens, isolates of Gram-negative organisms were more commonly found in HCA PM subgroup than in CA PM subgroup (47.6% [10/21] of patients with HCA PM vs. 20.7% [12/58] of patients with CA PM; P = 0.01). Conclusion: Gram-positive cocci such as S. aureus and streptococci were dominant etiologies in community-onset PM, whereas MRSA appears to an uncommon causative organism of PM in Korea. Enteric Gram-negative organisms should also be considered as major etiologies, especially in HCA PM patient population in Korea. [ABSTRACT FROM AUTHOR]

Background This study aimed to evaluate whether fluvoxamine reduces clinical deterioration in adult patients with mild to moderate coronavirus disease 2019 (COVID-19), and to identify risk factors for clinical deterioration in patients admitted to a community treatment center (CTC). Materials and Methods A randomized, placebo-controlled trial was conducted in a CTC, in Seoul, Korea from January 15, 2021, to February 19, 2021. Symptomatic adult patients with positive results of severe acute respiratory syndrome coronavirus 2 real time-polymerase chain reaction within 3 days of randomization were assigned at random to receive 100 mg of fluvoxamine or placebo twice daily for 10 days. The primary outcome was clinical deterioration defined by any of the following criteria: oxygen requirement to keep oxygen saturation over 94.0%, aggravation of pneumonia with dyspnea, or World Health Organization clinical progression scale 4 or greater. Results Of 52 randomized participants [median (interquartile range) age, 53.5 (43.3 - 60.0) years; 31 (60.0%) men], 44 (85.0%) completed the trial. Clinical deterioration occurred in 2 of 26 patients in each group (P >0.99). There were no serious adverse events in either group. Clinical deterioration occurred in 15 (6.0%) of 271 patients admitted to the CTC, and all of them were transferred to a hospital. In multivariate analysis, age between 55 and 64, fever and pneumonia at admission were independent risk factors for clinical deterioration. Conclusion In this study of adult patients with symptomatic COVID-19 who were admitted to the CTC, there was no significant differences in clinical deterioration between patients treated with fluvoxamine and placebo. [ABSTRACT FROM AUTHOR]

Background: Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales bacteremia is associated with significant mortality; however, no optimal antibiotic strategy is available. We aimed to evaluate the clinical outcomes according to the antibiotic regimens and identify risk factors for mortality in patients with KPC-producing K. pneumoniae and Escherichia coli bacteremia. Materials and Methods: This retrospective cohort study included all adult patients with monomicrobial bacteremia (KPC-producing K. pneumoniae or E. coli) between January 2011 and March 2021 at a 2,700-bed tertiary center. Results: Ninety-two patients were identified; 7 with E. coli bacteremia, and 85 with K. pneumoniae bacteremia. Thirty-day mortality was 38.0% (35/92). Non-survivors were more likely to have had nosocomial infection (88.6% vs. 63.2%, P = 0.01), high APACHE II scores (mean [interquartile range], 22.0 [14.0 - 28.0] vs. 14.0 [11.0 - 20.5], P <0.001), and septic shock (51.4% vs. 26.3%, P <0.001) and less likely to have been admitted to the surgical ward (5.7% vs. 22.8%, P = 0.04), undergone removal of eradicable foci (61.5% vs. 90.6%, P = 0.03), and received appropriate combination treatment (57.1% vs. 78.9%, P = 0.03) than survivors. No significant difference in mortality was observed according to combination regimens including colistin, aminoglycoside, and tigecycline. In multivariable analysis, high APACHE II scores (adjusted odds ratio [aOR], 1.14; 95% confidence interval [CI], 1.06 - 1.23, P <0.001), and appropriate definitive treatment (aOR, 0.25; CI, 0.08 - 0.74, P = 0.01) were independent risk factors for mortality. Conclusion: High APACHE II scores and not receiving appropriate definitive treatment were associated with 30-day mortality. Mortality did not significantly differ according to combination regimens with conventional drugs such as aminoglycoside and colistin. [ABSTRACT FROM AUTHOR]

배경: Despite the known clinical benefit of remdesivir in SARS-CoV-2 infection, its usage has been limited in patients with impaired renal function due to concern about the liver and renal toxicities by the accumulation of sulfobutylether-β-cyclodextrin. We compared adverse events between remdesivir-treated and non-remdesivir-treated groups in COVID-19 patients with renal impairment. 방법: Adult COVID-19 patients with a glomerular filtration rate of <30 ml/min/1.73 m2 at admission to a tertiary care hospital between November 2020 and March 2022 were retrospectively enrolled. Data on serum creatinine and liver chemistry tests at day 3 or 5, 10, 15, and 30 from admission or the start of remdesivir therapy were collected. 결과: A total of 101 patients with impaired renal function were enrolled including 34 patients receiving renal replacement therapy. Of 101 patients, 64 received remdesivir, while 37 did not. The median duration of remdesivir therapy was 4 (interquartile range, 3-5). Among patients who did not need dialysis initially, 18% (7/38) of remdesivir-treated patients developed acute kidney injury (AKI) at day 3-5, while 43% (16/29) of non-remdesivir-treated patients did. The proportion of patients with AKI decreased over time in remdesivir-treated patients (Figure 1). At day 3-5, 20% (13/64) of remdesivir-treated patients developed liver injury (mostly mild injury), while 30% (11/37) of non-remdesivir-treated patients did. There was no significant increase in alanine aminotransferase level over time in remdesivir-treated patients (Figure 1). No serious renal and hepatic adverse events related to remdesivir were observed. 결론: No significant increases in liver and kidney injury associated with remdesivir therapy were observed. These findings suggest that remdesivir therapy should not be easily withheld due to safety concerns of sulfobutylether-β-cyclodextrin in COVID-19 patients with renal impairment. [ABSTRACT FROM AUTHOR]

배경: Bacteremia caused by carbapenemase-producing Enterobacterales (CPE) is a growing concern due to its high mortality and limited treatment option. We evaluated the characteristics of subsequent CPE bacteremia in CPE stool carriers and analyzed risk factors for CPE bacteremia compared with non-CPE Enterobacter bacteremia. 방법: We retrospectively analyzed adult patients confirmed to have CPE colonization in stool surveillance culture in a tertiary hospital between January 2018 and February 2022. All episodes of Enterobacterales bacteremia within 6 months after CPE colonization were identified. 결과: During the study periods, a total of 1,174 patients were identified as CPE stool carriers. Of these patients, 58 (4.9%) experienced 70 episodes of subsequent CPE bacteremia after CPE colonization, whereas 102 (8.7%) had 123 episodes of subsequent non-CPE Enterobacterales bacteremia. Colonization with KPC producer, K. pneumoniae, and E. coli was significantly associated with CPE bacteremia (Table 1). Subsequent Enterobacterales bacteremia in CPE carriers was more frequently caused by non-CPE than by CPE (8.7% vs. 4.9%, p <0.001). When comparing the first episode of Enterobacterales bacteremia according to carbapenemase production, colonization with KPC producer and K. pneumoniae, multiple sites colonization, high Pitt’s score, ICU care, recent abdominal surgery, and prior carbapenem use were significantly associated with CPE bacteremia (Table 2). Multivariable analysis revealed that ICU care (adjusted odds ratio [aOR]: 4.09, 95% confidence interval 1.52 to 11.01, p <0.01), KPC colonizer (aOR: 4.22, p <0.01) and abdominal surgery within a week (aOR: 13.15, p =0.03) were independent risk factors for CPE bacteremia. 결론: In CPE carriers, non-CPE Enterobacterales were 1.8 times more likely to cause bacteremia than CPE. In a CPE carrier in ICU, colonized with KPC, and recent history of intraabdominal surgery, empirical therapy for CPE should be considered when sepsis is suspected. [ABSTRACT FROM AUTHOR]

Background: Carbapenemase-producing Enterobacteriaceae (CPE) are highly drug-resistant pathogens. Screening the contacts of newly-identified CPE patients is crucial for nosocomial transmission control. We evaluated the acquisition rate of CPE in close contacts as a function of CPE genotype. Materials and Methods: This study was conducted in Asan Medical Center, a 2,700-bed, tertiary teaching hospital in Seoul, Korea, between November 2010 and October 2017. Index cases were defined as patients with positive tests for CPE from any infected or colonized site during hospitalization who had no direct epidemiologic linkage with existing CPE patients; close contact patients were defined as those whose hospital stay overlapped with the stay of an index case for at least one day and who occupied the same room or intensive care unit (ICU). Secondary patients were defined as those who produced positive CPE culture isolates from surveillance cultures that had the same CPE enzyme as that of the index case patients. Results: A total of 211 index case patients and 2,689 corresponding contact patients were identified. Of the contact patients, 1,369 (50.9%) including 649 New-Delhi metallo-betalactamase- 1 (NDM-1) and 448 Klebsiella pneumoniae carbapenemase (KPC)-producing CPE exposures were screened, and 44 secondary patients (3.2%; 95% confidence interval 2.3 - 4.3%) were positive for NDM-1-producing CPE (16 patients) and KPC-producing (24 patients) CPE. The CPE acquisition rate (5.4%) for KPC-producing CPE exposures was significantly higher than that for NDM-1 exposures (2.7%) (P = 0.01). Conclusion: The CPE acquisition rate was 3.2% among close contacts sharing a multi-patient room, with about a two-fold higher risk of KPC-producing CPE than NDM-1-producing CPE. [ABSTRACT FROM AUTHOR]

Skin and soft tissue infection (SSTI) is common and important infectious disease. This work represents an update to 2012 Korean guideline for SSTI. The present guideline was developed by the adaptation method. This clinical guideline provides recommendations for the diagnosis and management of SSTI, including impetigo/ecthyma, purulent skin and soft tissue infection, erysipelas and cellulitis, necrotizing fasciitis, pyomyositis, clostridial myonecrosis, and human/animal bite. This guideline targets community-acquired skin and soft tissue infection occurring among adult patients aged 16 years and older. Diabetic foot infection, surgery-related infection, and infections in immunocompromised patients were not included in this guideline. [ABSTRACT FROM AUTHOR]

Background: Trimethoprim/sufamethoxazole (TMP/SMX) is the recommended treatment for Pneumocystis jirovecii pneumonia (PCP). However, the efficacy and the safety of alternative salvage treatments are less guarauteed especially when patient experiences treatment failure and/or an adverse drug reactions (ADR). The purpose of this study is to recognize potential risk factors imitating successful treatment with TMP/SMX among PCP patients. Materials and Methods: Ninety one adult patients diagnosed with PCP were inckided after searching electronical medical records from January 2013 thro니gh July 2015 at Asan Medical Center Seoul, Korea. We compared clinical characteristics and laboratory findings including bronchoalveolar lavage (BAL) fluid analysis in patients who experienced TMP/SMX treatment fail니re or ADR (the case group) versus those who did not (the control group). Results: Among the enrolled PCP patients, 39 (42.9%) required salvage treatment owing to either treatment failure (28, 28.6%) and/or ADR (17, 18.7%). The BAL lymphocyte percentage (25% [IQR, 8-40%] vs. 47% [IQR, 15-62%]; P = 0.005) was lower in the case group. Diabetes mellitus (adjusted odds ratio [aOR] 4.98, 95% confidence interval [95% Cl] 1.20-18.58), glomer- ular filtration rate <50 mL/min (aOR 4.48, 95% Cl 1.08-18.66), and BAL lymphocyte percentage <45% (aOR 9.25, 95% Cl 2.47-34.58) were independently associated with the case group in multivariate analysis. Conclusion: This study suggests that BAL lymphocyte count may play some role during PCP treatment. Further studies should be followed to reveal what the role of BAL lymphocyte is in the PCP treatment. [ABSTRACT FROM AUTHOR]

배경: Medical students are essential parts of healthcare system and consequently were prioritized for COVID-19 vaccination over similar age groups. In this study, we evaluated immune response against the omicron variant after the mRNA-based COVID-19 booster vaccination in medical students. 방법: Medical students at Chung-Ang University who had received the two-dose primary mRNA-1273 vaccines in July 2021 were enrolled. Neutralizing response against wild type and omicron variant was evaluated before (five months after the two-dose primary vaccines) and four months after the booster vaccine, using GenScript SARS-CoV-2 surrogate virus neutralization test kit. SARS-CoV-2-specific T cell response was evaluated four months after the booster vaccine, using Euroimmune SARS-CoV-2 Interferon Gamma Release Assay. 결과: A total of 56 students were enrolled; The median age was 24.0 and 46.4% were male. The booster vaccines were administered in December 2021. Nineteen students (33.9%) developed COVID-19 two months after booster vaccine. Of 56 students, 35 students (12 infected and 23 uninfected) were available for blood sampling after the booster vaccine. Four months after the booster, the median of SARS-CoV-2 specific IgG (5.23 AU/mL vs. 5.12 AU/mL, P < 0.001, Fig.1) and neutralizing response to Omicron variant (96.22% vs. 27.18%, P < 0.001, Fig.2) were higher in infected students than uninfected students. There was no significant difference in SARS-CoV-2 specific T cell response between them (563.69 mIU/mL vs. 344.25 mIL/mL, P = 0.21). Of 23 infection-naive students, students with mRNA-1273 booster had a significant higher neutralizing response against the omicron variant than those with BNT162b2 booster (69.07% vs. 26.43%, P = 0.02). 결론: Hybrid immunity had strong neutralizing response against the omicron variant. mRNA-1273 booster was significantly associated with higher neutralizing response against the omicron variant than BNT162b2 booster. [ABSTRACT FROM AUTHOR]

배경: Nirmatrelvir/ritonavir (NM/r) and molnupiravir (MP) are oral agents that hinder replication of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2 and prevent progression of severe Coronavirus disease-19 (COVID-19) infection. These agents have been prescribed for patients who are at high risk of COVID-19 progression. Nowdays, there are several reports of recrudescence of COVID-19 infection after taking NM/r, but the rate of rebound of SARS-CoV-2 infection after taking NM/r or MP is not definitely known and still under investigation. This study investigated the rate of rebound of COVID-19 infection after taking NM/r or MP. 방법: This prospective cohort study was conducted in a 2,715-bed tertiary teaching hospital from August to September 2022. Patients who were confirmed with COVID-19 visited the COVID-19 outpatient clinic center and were enrolled in this study. Symptom scores of COVID-19 disease were calculated on day 0 (D0, the date of the first visit to clinic), D7, D14, D28, and the day of symptom rebound for each patient, with giving one and two points for every mild and severe symptom. COVID-19 rebound was defined as when the symptom score on the day of rebound increased by 25% from the previous lowest score. 결과: Total 45 patients were enrolled in this study, but one patient died of underlying diseases during the study period and two patients withdrew consents. Among 42 patients, there were 4 (9.5%, 95% confidence interval (CI) 1.1-10.2) cases of COVID-19 rebound after taking oral antivirals. Three patients and one patient with COVID-19 rebound took MP and NM/r, respectively. The median duration of D0 to the day of symptom rebound was 10.5 days (interquartile range (IQR) 9.0-13.0). Also, the median duration of the end of treatment to the days of symptom rebound was 6.5 days (IQR 5.0-9.0). 결론: The rate of COVID-19 symptom rebound after taking oral antiviral agents was 9.5% (95% CI 1.1-10.2) and COVID-19 rebound occurred in patients not only taking NM/r but also MP. [ABSTRACT FROM AUTHOR]

배경: There is concern regarding vaccine-induced immune escape against the omicron variant of SARS-CoV-2 in people living with human immunodeficiency (HIV) (PLWH). Thus, we compared humoral and cellular responses against the omicron variant of SARS-CoV-2 after the third dose of a coronavirus disease 2019 (COVID-19) vaccine between PLWH and healthcare workers (HCWs). 방법: This was a prospective study performed at Chung-Ang University Hospital, Seoul, South Korea. We enrolled PLWH and HCWs vaccinated with at least two doses of COVID-19 vaccine. We compared neutralizing responses using the GenScript SARS-CoV-2 surrogate virus neutralization test kit and SARS-CoV-2–specific T cell responses using the Euroimmun SARS-CoV-2 Interferon Gamma Release Assay after the third vaccination in PLWH with HCWs. 결과: Most PLWH (84.2%) had fully suppressed viral loads and CD4 T cell counts were well-controlled with a median count of 586.3 cells/μl. Twenty-nine PLWH and 114 HCWs were included in the study to analyze humoral and cellular immunity after the third vaccination. The neutralizing responses against the omicron variant in PLWH were not significantly different from those in HCWs (43.94% vs. 51.77%, P=0.42). However, neutralizing responses against the omicron variant were significantly impaired by about 50% compared with wild type SARS-CoV-2 in PLWH (43.94% vs. 97.46%, P <0.001) and HCWs (51.77% vs. 97.74%, P <0.001). In addition, SARS-CoV-2-specific T cell responses related to the production of IFN-γ were similar between PLWH and HCWs (434.84 vs. 484.96 mIU/ml, P=0.90). 결론: Although the neutralizing responses against the omicron variant in well-controlled PLWH were comparable to those of HCWs, the responses were much lower than those against wild type SARS-CoV-2 in both PLWH and HCWs. Therefore, the risk of breakthrough SARS-CoV-2 infection due to the currently circulating omicron variant is still high despite three doses of the COVID-19 vaccine in PLWH and will not differ from HCWs. [ABSTRACT FROM AUTHOR]

Background Varicella-zoster virus (VZV) is one of the most common etiologies of aseptic meningitis. The severest manifestation of VZV meningitis is occasionally confused with tuberculous meningitis (TBM). Thus, we investigated the clinical manifestations of VZV meningitis as compared with those of TBM. Materials and Methods All adult patients who were diagnosed with VZV meningitis or TBM were enrolled at a tertiary hospital in Seoul, South Korea, during an 8-year period. The clinical characteristics and cerebrospinal fluid (CSF) profile of patients were analyzed. Results Seventy-nine patients with VZV meningitis and 24 patients with TBM were enrolled in this study. Of the 79 patients with VZV meningitis, 63 (80%) did not received empirical anti-tuberculous therapy (Group 1) and the remaining 16 (20%) received empirical anti-tuberculous therapy (Group 2), compared with 24 patients with TBM (Group 3). Altered mental status, intensive care unit (ICU) admission, neurologic sequelae, CSF protein levels, and CSF adenosine deaminase levels revealed a trend of being higher in Group 3 than Group 2, which was higher than Group 1. However, the CSF/serum glucose ratio was significantly lower in Group 3 than in Group 1 or Group 2. Conclusion About one fifth of VZV meningitis cases presented as severe manifestations, mimicking TBM. The CSF/serum glucose ratio might be useful to differentiate VZV meningitis from TBM until definite diagnostic tests are available. Physicians should keep in mind that a differential diagnosis between severe VZV meningitis and TBM is needed. [ABSTRACT FROM AUTHOR]

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging febrile illness. While many kinds of severe complications including acute renal failure have been reported, rhabdomyolysis is rarely reported in association with SFTS. A 54-year-old female farmer was admitted with fever and diffuse myalgia. Laboratory finding showed thrombocytopenia, leukopenia, azotemia, extremely elevated muscle enzyme levels and myoglobinuria. We describe a fatal case of rhabdomyolysis with acute renal failure complicated by SFTS. [ABSTRACT FROM AUTHOR]

We evaluated the impact of revised Clinical and Laboratory Standards Institute (CLSI) breakpoints for broad-spectrum cephalosporins (BSCs) on the susceptibilities of 1,742 isolates of Enterobacter species, Serratia marcescens, Citrobacter freundii, and Morganella morganii. The 2011 CLSI criteria for cefotaxime and ceftazidime reduced the rates of susceptibility by 2.9% and 5.9%, respectively. The 2014 CLSI criteria for cefepime reduced the rate of susceptibility by 13.9%, and categorized 11.8% isolates as susceptible-dose dependent (SDD) for cefepime. Among 183 isolates with extended-spectrum β-lactamase (ESBL) phenotype, implementation of the new criteria reduced the rates of susceptibility to cefotaxime, ceftazidime, and cefepime by 2.8%, 14.8%, and 53.6%, respectively. The proportion of ESBL phenotype among BSC-susceptible isolates was low (0.9% for cefotaxime, 3.0% for ceftazidime, and 3.3% for cefepime). In summary, implementation of new CLSI criteria led to little change in susceptibility to cefotaxime and ceftazidime but a substantial change in susceptibility to cefepime. The recognition of revised CLSI criteria for BSC and SDD will help clinicians to select the optimal antibiotic and dosing regimen. [ABSTRACT FROM AUTHOR]

Background: Postoperative bacterial meningitis (PBM) is a serious potential complication after neurosurgery. Early diagnosis and introduction of antimicrobial therapy are necessary to reduce the rate of fatal outcomes from PBM. However, PBM is not easily differentiated from postoperative aseptic meningitis (PAM), which usually has favorable clinical outcomes. Serum procalcitonin (S-PCT) has been found to be a useful marker for distinguishing community-acquired bacterial from viral meningitis. We investigated the predictive performance of S-PCT for PBM in patients who underwent neurosurgery. Materials and Methods: Between September 2009 and August 2010, we prospectively collected data from patients who underwent neurosurgery and had cerebrospinal fluid (CSF) pleocytosis within 14 days of surgery. Based on the CSF culture results, patients were categorized as either PBM or PAM cases. We compared the laboratory test results including S-PCT levels between PBM and PAM cases, and investigated the predictive performance of S-PCT for PBM. Results: During the study period, PBM and PAM occurred in 14 and 64 patients, respectively. There was no significant difference in CSF profiles between PBM and PAM cases. S-PCT level ≥ 0.15 ng/mL (50.0% vs. 20.0%, P = 0.07) and C-reactive protein (CRP) level ≥ 2.5 mg/dL (75.0% vs. 46.5%, P = 0.16) tended to be more frequent in PBM than in PAM cases. A blood white blood cell (B-WBC) count ≥ 9,500/mm³ was more frequently found in PBM cases (85.7% vs. 50.8%, P = 0.02) than in PAM cases. For the diagnosis of PBM, an S-PCT level ≥ 0.15 ng/mL had a specificity of 80.0%. The combined criteria of a CRP level ≥ 2.5 mg/dL, B-WBC count ≥ 9,500/mm³, and an S-PCT level ≥ 0.15 ng/mL had the highest specificity (92.6%) of all the criteria. An S-PCT level ≥0.15 ng/mL had low sensitivity (50.0%), and the combined criteria of CRP level ≥ 2.5 mg/dL, B-WBC count ≥ 9,500/mm³, and S-PCT level ≥ 0.15 ng/mL had an improved sensitivity of 85.7%. However, the sensitivity did not significantly differ from that of a B-WBC count ≥ 9,500/mm³ (85.7%). Conclusions: S-PCT showed limited performance for the diagnosis of postoperative meningitis. However, it could be a useful adjunct for the improvement of diagnostic sensitivity when used in combination with other inflammatory markers. [ABSTRACT FROM AUTHOR]

Background: Cytomegalovirus (CMV) retinitis is one of the most important tissue-invasive CMV diseases in immunocompromised patients. Since 1980, non-invasive diagnostic methods, notably the CMV antigenemia assay, have been widely used as adjunct tests to diagnose tissue-invasive CMV diseases. However, there are limited data on the diagnostic value of the CMV antigenemia assay for diagnosing CMV retinitis. Materials and Methods: We performed a retrospective review of all cases of CMV retinitis at Asan Medical Center, Seoul, South Korea over a 9-year period. The diagnosis of CMV retinitis was made by experienced ophthalmologists according to medical history and an ophthalmoscopic appearance of typical retinopathy, together with absence of an alternative diagnosis. Results: We analyzed 44 patients with CMV retinitis (affecting 57 eyes) for whom the CMV antigenemia assay was performed. Of the 44 patients, 31 (70%) were HIV-uninfected and 13 (30%) were HIV-infected. The overall sensitivity of the CMV antigenemia assay was 66% (95% confidence interval [CI] 50-80%). The test's sensitivity showed a non-significant trend towards being higher in HIV-infected patients than in HIV-uninfected patients (sensitivity 85% vs 58%, respectively, P = 0.16). In a subgroup analysis of the 35 patients without other concurrent tissue-invasive CMV disease, the sensitivity of the CMV antigenemia assay was 57% (95% CI 40-74%). Conclusions: The CMV antigenemia assay has limited value as a non-invasive diagnostic adjunct test for CMV retinitis. Therefore, the results of the assay need to be interpreted in the context of underlying disease, clinical presentation, and ophthalmoscopic findings. [ABSTRACT FROM AUTHOR]

Middle East Respiratory Syndrome (MERS) is an acute viral respiratory illness with high mortality caused by a new strain of betacoronavirus (MERS-CoV). Since the report of the first patient in Saudi Arabia in 2012, large-scale outbreaks through hospital- acquired infection and inter-hospital transmission have been reported. Most of the patients reported in South Korea were also infected in hospital settings. Therefore, to eliminate the spread of MERS-CoV, infection prevention and control measures should be implemented with rigor. The present guideline has been drafted on the basis of the experiences of infection control in the South Korean hospitals involved in the recent MERS outbreak and on domestic and international infection prevention and control sidelines . To ensure efficient MERS-CoV infection prevention and control, care shouId be taken to provide comprehensive infection control measures including contact control, hand hygiene, personal protective equipment, disinfection, and environmental cleaning. [ABSTRACT FROM AUTHOR]

Background: Doripenem is the most recently introduced antimicrobial agent of the carbapenem class. It is a valuable therapeutic option in the context of increasing antimicrobial resistance to imipenem and meropenem among gram-negative bacilli (GNB) clinical isolates. However, clinicians are usually rekictant to prescribe doripenem, because susceptibility to doripenem is not automatically reported by most clinical laboratories and the in vitro activity of doripenem against clinically significant GNB isolates remains uncertain. Materials and Methods: We investigated the in vitro antibacterial activity of doripenem in GNB blood isolates in a tertiary care center. Over a period of 10 months, 212 adult bacteremia cases were treated at the study hospital. Doripenem susceptibility testing was performed for the 212 blood isolates by the disk diffusion method, and clinical data were collected. Results: Among the blood isolates, the rate of doripenem resistance (7.5%) was lower than that of imipenem (12.9%) or other antiGNB antimicrobial agents, except amikacin (2.1%). Almost all imipenem-susceptibIe GNB blood isolates (181/182, 99.5%) were susceptible to doripenem. Whereas doripenem resistance was rarely observed in Enterobacteriaceae (2/181, 1.1%), it was frequently observed in patients with non-fermentatative GNB (12/27, 44.4%), hospital-acquired infections (7/27, 25.9%), and pne니monia (11/49, 22.4%). Conclusion: Doripenem exhibited more potent in vitro activity against GNB blood isolates than other anti-GNB antimicrobial agents in a tertiary care center where it was infrequently prescribed compared with other carbapenems. However, its clinical utility may be limited due to the increasing number of carbapenem-resistant non-fermentative GNB infections. [ABSTRACT FROM AUTHOR]

Background: Cytomegalovirus (CMV) is one of the most important opportunistic infections in transplant recipients. Currently sero-positivity for CMV IgG before solid organ transplantation is the laboratory test of choice for stratifying the risk of CMV reactivation after solid organ transplantation. Theoretically, CMV-specific cell-mediated immune responses before solid organ transplantation should further categorize patients as high or low risk of CMV development. We therefore evaluated the usefulness of the CMV-specific enzyme-linked immunospot (ELISPOT) assay in kidney transplant (KT) candidates for predicting the development of CMV infections after transplantation. Materials and Methods: All adult CMV IgG (+) recipients admitted to the KT institute between March 2014 and June 2014 were enrolled, and CMV infections after KT were observed between March 2014 and December 2014. All patients underwent CMV pp65 and IE1-specific ELISPOT assays before transplantation. CMV infection was defined in the presence of CMV antigenemia, CMV syndrome, or tissue-invasive CMV disease. We used the data to select optimal cut-off values for pp65 and IE1, respectively, on ROC curves. Results: A total of 69 transplant recipients involving 54 (78%) living-donor KT, 9 (13%) deceased-donor KT, 3 (4%) kidney-pancreas transplants, and 3 (4%) pancreas transplants were enrolled. Of the 69 patients, 27 (39%) developed CMV infections. There was no association between the IE1-specific ELISPOT assay and CMV infection. However, only 15 (31%) of the 48 patients with positive pp65-specific ELISPOT results (>10 spots/2.0 x 105 cells) developed CMV infections, whereas 12 (57%) of the 21 patients with negative pp65-specific ELISPOT results developed CMV infection (P = 0.04). Conclusion: Negative pp65-specific ELISPOT assay results before transplantation appear to predict the subsequent development of CMV infections after transplantation in CMV IgG (+) KT recipients. Therefore, risk stratification of CMV IgG (+) recipients using the CMV-specific ELISPOT, together with preventive strategies, may further reduce CMV development. [ABSTRACT FROM AUTHOR]

Actinomyces meyeri is rarely isolated in cases of actinomycosis. The identification of A. meyeri had historically been difficult and unreliable. With the recent development of 16S ribosomal RNA (16S rRNA) sequencing, Actinomyces species such as A. meyeri can be isolated much more reliably. A. meyeri often causes disseminated disease, which can be secondary to frequent pulmonary infections. A penicillin-based regimen is the mainstay of A. meyeri treatment, with a prolonged course usually required. Here, we report a case of pulmonary actinomycosis with brain abscess caused by A. meyeri that was initially thought to represent lung cancer with brain metastasis. [ABSTRACT FROM AUTHOR]

Limited data are available on which factors are associated with strong immunologic responses to T-SPOT.TB. We investigated the factors associated with strong positive responses in patients with extrapulmonary tuberculosis (E-TB). Of 173 patients with E-TB who gave positive results on T-SPOT.TB, 26 (15%) with a strong positive response (defined as ≥1,000 spot-forming units (SFU)/2.5×105 PBMC to ESAT-6 or CFP-10) and 71 (41%) with a low positive response (≤ 99 SFU (6-99 SFU)/2.5×105 PBMC) were further analyzed. Miliary TB was independently associated with a strong positive response to T-SPOT.TB, while advanced age and immunosuppression were independently associated with weak positive T-SPOT.TB responses. [ABSTRACT FROM AUTHOR]