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Panton-Valentine leukocidin (PVL) is a virulent cytotoxin and an indicator of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection. In this study, we evaluated the prevalence and clinical and molecular characteristics of PVL-positive invasive S. aureus (ISA) infections in Korea.A collection of 1,962 nonduplicate clinical isolates were screened for multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec), accessory gene regulator typing, major toxins, and antimicrobial susceptibility. Twenty-eight (1.4%) PVL-positive S. aureus samples were found; of them 19 (67.9%) were MRSA (8 CA and 11 healthcare-associated infections). Seventeen patients (60.7%) were men (median age: 63 years; range: 13-93 years) and 12 patients (42.9%) had no underlying comorbidities. The most common infections were skin and skin structure infection (SSSI) and pneumonia. The 30-day mortality rate was 37.0%. The most common PVL-positive MRSA clones were ST8-SCCmec IVa and ST30-SCCmec IVc along with their single-locus variants. Antimicrobial susceptibility and toxin-gene profile differed according to the clone.ISA infections caused by PVL-positive strains are rare in Korea, with the two most common infections being SSSI and pneumonia. Our findings indicated that several PVL-positive MRSA clones, predominantly ST8-SCCmecIVa and ST30-SCCmecIVc, were circulating and causing sporadic cases of ISA infections in the community and hospital settings.

Understanding the long-term kinetics of antibodies in coronavirus disease 2019 (COVID-19) is essential in interpreting serosurvey data. We investigated the antibody response one year after infection in 52 mildly symptomatic patients with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection, using three commercial immunoassays and a surrogate virus neutralization test (sVNT) kit. Anti-N pan-immunoglobulin (Ig), anti-S IgG, and anti-S1 IgG were detected in 43 (82.7%), 44 (84.6%), and 30 (57.7%), respectively. In 49 (94.2%), the antibody could be detected by either anti-N pan-Ig or anti-S IgG assay. In the sVNT, 30 (57.7%) had positive neutralizing activity. Despite waning immunity, SARS-CoV-2 antibodies can be detected up to one year after infection, even in mild COVID-19 patients., Graphical Abstract

Waning humoral immunity in coronavirus disease patients has raised concern over usefulness of serologic testing. We investigated antibody responses of 58 persons 8 months after asymptomatic or mildly symptomatic infection with severe acute respiratory syndrome coronavirus 2. For 3 of 4 immunoassays used, seropositivity rates were high (69.0%–91.4%).

Background Infections caused by carbapenem-resistant Enterobacteriaceae (CRE) are associated with high mortality rates and their treatment is difficult because treatment is limited to certain antibiotics, such as colistin and tigecycline. We aimed to perform active surveillance culture of CRE (ASC-CRE) to monitor the prevalence of CRE acquisition during intensive care unit (ICU) care and to examine the potential risk factors associated with CRE acquisition. Methods We conducted ASC-CRE on patients who were admitted to the ICU in the emergency room at a tertiary hospital. Rectal swabs were analyzed using methods established by the Centers for Disease Control and Prevention. To detect carbapenemase-producing CRE, a polymerase chain reaction assay to detect five carbapenemase genes (blaNDM, blaKPC, blaVIM, blaIMP-1, and blaOXA-48) was performed. Results There were 22 CRE acquisition in 21 patients (2.6%, 21/810) and the incidence of CRE acquisition was 4.3/1,000 person-days, respectively. The most common species detected was Klebsiella pneumoniae (72.7%, 16/22), and 9 carbapenemase-producing CREs (7 blaKPC and 2 blaNDM) were detected. Independent risk factors associated with CRE acquisition were men gender (adjusted odds ratio [aOR], 5.3; 95% confidence interval [CI], 1.3–21.3), history of admission within one year (aOR, 3.9; 95% CI, 1.2–12.1), co-colonization with multidrug-resistant Acinetobacter baumannii (aOR, 15.6; 95% CI, 3.6–67.8) and extended-spectrum β-lactamases-producing bacteria (aOR, 4.7; 95% CI, 1.5–14.6), and exposure to glycopeptide antibiotics (aOR, 3.6; 95% CI, 1.3–9.9). Conclusion The identification of patients with risk factors for CRE acquisition and early detection of CRE acquisition using ASC-CRE may be useful for CRE control., Graphical Abstract

Given the mode of transmission of Middle East respiratory syndrome (MERS), healthcare workers (HCWs) in contact with MERS patients are expected to be at risk of MERS infections. We evaluated the prevalence of MERS coronavirus (CoV) immunoglobulin (Ig) G in HCWs exposed to MERS patients and calculated the incidence of MERS-affected cases in HCWs. We enrolled HCWs from hospitals where confirmed MERS patients had visited. Serum was collected 4 to 6 weeks after the last contact with a confirmed MERS patient. We performed an enzyme-linked immunosorbent assay (ELISA) to screen for the presence of MERS-CoV IgG and an indirect immunofluorescence test (IIFT) to confirm MERS-CoV IgG. We used a questionnaire to collect information regarding the exposure. We calculated the incidence of MERS-affected cases by dividing the sum of PCR-confirmed and serology-confirmed cases by the number of exposed HCWs in participating hospitals. In total, 1169 HCWs in 31 hospitals had contact with 114 MERS patients, and among the HCWs, 15 were PCR-confirmed MERS cases in study hospitals. Serologic analysis was performed for 737 participants. ELISA was positive in five participants and borderline for seven. IIFT was positive for two (0.3%) of these 12 participants. Among the participants who did not use appropriate personal protective equipment (PPE), seropositivity was 0.7% (2/294) compared to 0% (0/443) in cases with appropriate PPE use. The incidence of MERS infection in HCWs was 1.5% (17/1169). The seroprevalence of MERS-CoV IgG among HCWs was higher among participants who did not use appropriate PPE.

Background We estimated the prevalence and clinical impact of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA). The concordance between macromethod and glycopeptide resistance detection (GRD) E tests was determined. In addition, predictors of clinical outcomes in hospitalized patients with S. aureus bacteremia (SAB) or pneumonia (SAP) were evaluated. Methods We obtained 229 consecutive S. aureus isolates from all hospitalized patients at two university hospitals located in Busan and Yangsan, Korea. Standard, macromethod, and GRD E tests were performed. Additionally, we reviewed the medical records of all patients. Among the 229 patients, predictors of clinical outcomes were analyzed for 107 patients with SAB and 39 with SAP. Results Among the 229 isolates, 34.5% of S. aureus isolates and 50.7% of methicillin-resistant S. aureus isolates exhibited the hVISA phenotype based on the macromethod E test. hVISA was nearly associated with treatment failure in patients with SAB (P=0.054) and was significantly associated with treatment failure in patients with SAP (P=0.014). However, hVISA was not associated with 30-day mortality in patients with SAB or SAP. The concordance between the macromethod and GRD E tests was 84.2%. Conclusions hVISA is quite common in the southeastern part of Korea. hVISA is associated with treatment failure in patients with SAP.

AimsSevere fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease caused by the SFTS virus; primary manifestations are fever, thrombocytopenia, leukopenia and gastrointestinal symptoms. Before an aetiological diagnosis is made, SFTS patients can undergo bone marrow examination due to cytopenias. Although several studies have reported on bone marrow examination in SFTS patients, most do not provide adequate details. Bone marrow findings in SFTS patients were investigated in this study.MethodsAn observational study was conducted in SFTS patients who were hospitalised between 2013 and 2014 in two university hospitals in South Korea. Patients were included in the study if SFTS was confirmed by real-time PCR for the SFTS virus and a bone marrow examination was conducted. The morphologic findings of the bone marrow samples were reviewed.ResultsThree cases met the study inclusion criteria. One patient died of multiple organ failure. Haemophagocytosis was evident in the bone marrow samples of all three patients. Histiocytic hyperplasia and haemophagocytosis were more pronounced in the fatal case. One patient was diagnosed as having haemophagocytic lymphohistiocytosis.ConclusionsHaemophagocytosis in the bone marrow of SFTS patients may be common. In SFTS endemic areas, SFTS should be one of the differential diagnoses of fever of unknown origin with haemophagocytosis in the bone marrow.

To assess the outcome of Staphylococcus aureus bacteraemia (SAB) according to factors associated with necessity for longer treatment in conjunction with the duration of treatment.We prospectively collected the data of patients with SAB consecutively during 12 to 39 months from 11 hospitals. If multiple episodes of SAB occurred in one patient, only the first episode was enrolled. Factors associated with necessity for longer treatment were defined as follows: persistent bacteraemia, metastatic infection, prosthesis and endocarditis. If any of the factors were present, then the case was defined as longer antibiotic treatment warranted (LW) group; those without any factors were defined as shorter antibiotic treatment sufficient (SS) group. Poor outcome was defined as a composite of 90-day mortality or 30-day recurrence. Duration of antibiotic administration was classified as14 or ≥14 days in the SS group and28 or ≥28 days in the LW group.Among 2098 cases, the outcome was analysed in 1866 cases, of which 591 showed poor outcome. The SS group accounted for 964 cases and the LW group for 852. On multivariate analysis, age over 65 years, pneumonia, higher Sequential Organ Failure Assessment (SOFA) score and chronic liver diseases were risk factors for poor outcome. Administration of antibiotics less than the recommendation was associated with poor outcome, but this significance was observed only in the LW group (adjusted odds ratio = 1.68; 95% confidence interval, 1.00-2.83; p 0.05).Inappropriately short antibiotic treatment was associated with poor outcome in the LW group. Vigilant evaluation for risk factors to determine the duration of treatment may improve the outcome among patients with SAB.

BACKGROUND/AIMS Advanced human immunodeficiency virus (HIV) infection, despite sustained viral suppression by highly active antiretroviral therapy (HAART), is a risk factor for poor immunologic recovery. However, some patients with advanced infection do show immunologic recovery. In this study, predictive factors of immunologic recovery were analyzed in advanced HIV patients showing sustained viral suppression. METHODS A case-control study was conducted in HIV-infected adult patients with HIV-1 RNA < 50 copies/mL maintained for 4 years or longer and who were receiving HAART. Advanced HIV infection was defined as a baseline CD4 T cell count < 200/mm(3). Immunologic responders were defined as patients showing immunologic recovery (CD4 T cell counts ≥ 500/mm(3) at 4 years with HAART). To analyze the CD4 T cell kinetics, the CD4 slope (monthly changes in the CD4 T cell count) was estimated for each patient using a linear regression between the CD4 T cell count and the time since HAART initiation. RESULTS Of 102 eligible patients, 73 had advanced HIV, and 33 (45.2%) showed immunologic recovery. The median CD4 slopes (cells/mm(3) per month) during 0 to 6 and 0 to 12 months of HAART in the 73 advanced patients were significantly higher in responders than in non-responders (0 to 6 months, 38.6 vs. 22.8; 0 to 12 months, 24.5 vs. 13.5). Multivariate analyses showed opportunistic infections at the start of HAART (adjusted odds ratio [OR], 0.28) and a CD4 slope ≥ 20 during 0 to 12 months of HAART (adjusted OR, 10.10) were independently associated with immunologic recovery. CONCLUSIONS The CD4 slope can be an early predictor of long-term immunologic recovery in advanced HIV patients.

The epidemiological synergy between human immunodeficiency virus (HIV) and tuberculosis (TB) is a major threat to public health. However, the association between HIV and multi-drug resistant tuberculosis (MDR-TB) is not clear. To explore the association between HIV and MDR-TB infection, a case-control study was performed in Korea. A total of 1606 culture-proven TB patients (45 HIV vs. 1561 non-HIV) from January 2006 to October 2014 were included in this analysis. MDR-TB rates were 11.1% and 8.2% in the HIV and non-HIV groups, respectively (p=0.42), thus indicating that MDR-TB was not significantly associated with HIV infection in Korea.

Human granulocytic anaplasmosis (HGA) is a tick-borne rickettsial zoonosis with fever, thrombocytopenia, and leukopenia. HGA has been reported in Korea in 2013 but it is uncertain how long it has existed. A retrospective study was conducted on patients who underwent bone marrow examination due to fever and cytopenia, with no clear hematologic or microbiologic causes, from 2003 through 2012. Laboratory diagnosis was made by detecting 16S rRNA genes of Anaplasma phagocytophilum from the stored blood samples. Among the 70 patients, five (7.1%) HGA cases were found, and the earliest case dated back to 2006. Two cases met the diagnostic criteria of hemophagocytic lymphohistiocytosis (HLH) and were fatal. Although HGA has been prevalent in Korea since at least 2006, it is not always diagnosed and has posed a possible lethal health risk to the people in Korea. HGA should be considered as a cause of fever with cytopenia or HLH.

We report a patient with human granulocytic anaplasmosis in South Korea. The patient had fever and thrombocytopenia. Human granulocytic anaplasmosis was confirmed by seroconversion, PCR, and sequence analysis for Anaplasma phagocytophilum. Morulae were observed in the cultured HL-60 cells inoculated with blood from the patient.

Background Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was recently identified in China, South Korea and Japan. The objective of the study was to evaluate the epidemiologic and clinical characteristics of SFTS in South Korea. Methods/Principal Findings SFTS is a reportable disease in South Korea. We included all SFTS cases reported to the Korea Centers for Disease Control and Prevention (KCDC) from January 2013 to December 2015. Clinical information was gathered by reviewing medical records, and epidemiologic characteristics were analyzed using both KCDC surveillance data and patient medical records. Risk factors for mortality in patients with SFTS were assessed. A total of 172 SFTS cases were reported during the study period. SFTS occurred throughout the country, except in urban areas. Hilly areas in the eastern and southeastern regions and Jeju island (incidence, 1.26 cases /105 person-years) were the main endemic areas. The yearly incidence increased from 36 cases in 2013 to 81 cases in 2015. Most cases occurred from May to October. The overall case fatality ratio was 32.6%. The clinical progression was similar to the 3 phases reported in China: fever, multi-organ dysfunction, and convalescence. Confusion, elevated C-reactive protein, and prolonged activated partial thromboplastin times were associated with mortality in patients with SFTS. Two outbreaks of nosocomial SFTS transmission were observed. Conclusions SFTS is an endemic disease in South Korea, with a nationwide distribution and a high case-fatality ratio. Confusion, elevated levels of C-reactive protein, and prolonged activated partial thromboplastin times were associated with mortality in patients with SFTS., Author Summary Severe fever with thrombocytopenia (SFTS) is an emerging infectious disease that was first discovered in China in 2009. Subsequently, SFTS has also been found in South Korea and Japan. Here, we report the epidemiologic and clinical characteristics of 172 confirmed SFTS cases in South Korea that occurred since the first case was reported in 2013. SFTS was prevalent throughout South Korea, except for in urban areas. The incidence was relatively low in the western and southwestern rice field areas and the scarcely populated eastern mountainous area. Hilly areas were the major endemic regions. The incidence was increasing annually, and the case fatality ratio was 32.6%. A mental status of confusion, elevated levels of C-reactive protein, and prolongation of activated partial thromboplastin time were associated with mortality in patients with SFTS. Two outbreaks of nosocomial SFTS transmission were noted.

Sphingobacterium spiritivorum has been rarely isolated from clinical specimens of immunocompromised patients, and there have been no case reports of S. spiritivorum infection in Korea to our knowledge. We report a case of S. spiritivorum bacteremia in a 68-yr-old woman, who was diagnosed with acute myeloid leukemia and subsequently received chemotherapy. One day after chemotherapy ended, her body temperature increased to 38.3℃. A gram-negative bacillus was isolated in aerobic blood cultures and identified as S. spiritivorum by an automated biochemical system. A 16S rRNA sequencing analysis confirmed that the isolate was S. spiritivorum. The patient received antibiotic therapy for 11 days but died of septic shock. This is the first reported case of human S. spiritivorum infection in Korea. Although human infection is rare, S. spiritivorum can be a fatal opportunistic pathogen in immunocompromised patients.

A retrospective study was conducted to determine the mortality, causes and risk factors for death among HIV-infected patients receiving antiretroviral therapy (ART) in Korea. The outcomes were determined by time periods, during the first year of ART and during 1-5 yr after ART initiation, respectively. Patients lost to follow-up were traced to ascertain survival status. Among 327 patients initiating ART during 1998-2006, 68 patients (20.8%) died during 5-yr follow-up periods. Mortality rate per 100 person-years was 8.69 (95% confidence interval, 5.68-12.73) during the first year of ART, which was higher than 4.13 (95% confidence interval, 2.98-5.59) during 1-5 yr after ART. Tuberculosis was the most common cause of death in both periods (30.8% within the first year of ART and 16.7% during 1-5 yr after ART). During the first year of ART, clinical category B and C at ART initiation, and underlying malignancy were significant risk factors for mortality. Between 1 and 5 yr after ART initiation, CD4 cell count ≤ 50 cells/µL at ART initiation, hepatitis B virus co-infection, and visit constancy ≤ 50% were significant risk factors for death. This suggests that different strategies to reduce mortality according to the time period after ART initiation are needed.

Although a decrease in acquired immunodeficiency syndrome (AIDS)-related mortality has been documented in highly active antiretroviral therapy (HAART) era, there are no published data comparing specific causes of death between pre-HAART and HAART era in Korea. Mortality and cause of death were analyzed in three treatment periods; pre-HAART (1990-1997), early-HAART (1998-2001), and late-HAART period (2002-2011). The patients were retrospectively classified according to the treatment period in which they were recruited. Although mortality rate per 100 person-year declined from 8.7 in pre-HAART to 4.9 in late-HAART period, the proportion of deaths within 3 months of initial visit to study hospital significantly increased from 15.9% in pre-HAART to 55.1% in late-HAART period (P < 0.001). Overall, 59% of deaths were attributable to AIDS-related conditions, and Pneumocystis pneumonia (PCP) was the most common cause of death (20.3%). The proportion of PCP as cause of death significantly increased from 8.7% in pre-HAART to 31.8% in late-HAART period (P < 0.001). Despite of significant improvement of survival, there was still a high risk of early death in patients presenting in HAART era, mainly due to late human immunodeficiency virus (HIV) diagnosis and late presentation to care.

Background Little is known about the epidemiology on human papillomavirus (HPV) infection among HIV-infected men in Korea. The objective of this study was to determine the prevalence, genotype distribution and risk factors associated with anal HPV infection among HIV-infected men in Korea. Methods A single-center cross-sectional study was conducted with HIV-infected men in Korea. Participants completed a detailed sexual behavior risk factor questionnaire. Anal samples were collected for cytology and HPV genotyping. Factors associated with anal HPV infection were assessed using multivariable logistic regression, stratifying by sexual behaviour. Results A total of 201 HIV-infected men were included in the study: 133 were from men who have sex with men (MSM) and 68 from men who have sex with women (MSW). Any anal HPV infection was detected in 82.7% of HIV-infected MSM and in 51.5% of HIV- infected MSW (P < 0.001). High-risk HPV (HR-HPV) prevalence was higher among MSM (47.4%) than MSW (25.0%; P = 0.002). The HR-HPV types identified most frequently were HPV 16 (11%), HPV 18 (9.9%), and HPV 58 (5%) in MSM, and HPV 58(11%) and HPV 16 (8.9%) in MSW. Prevalence of any HPV types in 9-valent vaccine types was higher among MSM than MSW (47.4% vs 22.1%. P = 0.001). Abnormal anal cytology was more commonly detected in MSM than MSW (42.9% vs.19.1%, P < 0.001). In HIV-infected MSM, higher number of lifetime male sex partners was significantly associated with any anal HPV infection, but age was a significant risk factor associated with anal HR-HPV infection. Conclusion Anal HPV infection was highly prevalent in HIV-infected MSM in Korea, and also commonly found in HIV-infected MSW. In HIV-infected MSM, the significant risk factor for being infected with any HPV infection was lifetime number of male sexual partners, and with anal oncogenic HPV infection was age.

Recurrent Clostridium difficile infection (CDI) is one of the most difficult problems in healthcare infection control. We evaluated the risk factors associated with recurrence in patients with CDI. A retrospective cohort study of 84 patients with CDI from December 2008 through October 2010 was performed at Pusan National University Yangsan Hospital. Recurrence occurred in 13.1% (11/84) of the cases and in-hospital mortality rate was 7.1% (6/84). Stool colonization with vancomycin-resistant enterococci (VRE) (P = 0.006), exposure to more than 3 antibiotics (P = 0.009), low hemoglobin levels (P = 0.025) and continued use of previous antibiotics (P = 0.05) were found to be more frequent in the recurrent group. Multivariate analysis indicated that, stool VRE colonization was independently associated with CDI recurrence (odds ratio, 14.519; 95% confidence interval, 1.157-182.229; P = 0.038). This result suggests that stool VRE colonization is a significant risk factor for CDI recurrence.

Information about the genotype of varicella-zoster virus (VZV) is useful to monitor outbreaks of vaccine strains. However, in South Korea, where varicella vaccine was introduced in 1988, there are limited data about the genotype of VZV. VZV was isolated from vesicular lesions of patients with herpes zoster or varicella in South Korea between January 2007 and June 2009. DNAs were purified from single-passage isolates. The genotype was determined by sequence analysis of open reading frame (ORF) 22. The PstI restriction enzyme site in ORF 38 and the BglI restriction enzyme site in ORF 54 were evaluated by restriction enzyme analysis. Forty-four patients with herpes zoster and nine patients with varicella were enrolled. The median age of patients with herpes zoster was 59.5 (range, 10 to 77) years, and the median age of patients with varicella was 8 (range, 6 to 9) years. In sequence analysis of ORF 22, all isolates were genotype J, irrespective of the age group. In restriction enzyme analysis, 51 of 54 (94.3%) isolates contained a PstI site in ORF 38, and all isolates contained a BglI site in ORF 54. Our data suggest that genotype J has been circulating since the 1940s in South Korea.

Purpose Cryptococcal meningitis is a relatively common opportunistic infection in human immunodeficiency virus (HIV) patients and it can frequently occur in immunocompetent hosts without any apparent underlying disease. Nevertheless, little is known about cyptococcal meningitis in the Korean population. The purpose of this study was to evaluate the clinical features and initial laboratory findings of cryptococcal meningitis in patients with and without HIV at a tertiary care teaching hospital. Materials and Methods We performed a retrospective study at a tertiary care teaching hospital from January 2001 to December 2009. Eleven HIV positive patients and nine HIV negative patients were included. Results The most common symptoms were headache and fever in cryptococcal meningitis, and diabetic mellitus, end stage renal disease and liver cirrhosis were the main associated conditions in patients without HIV. Patients with HIV showed lower peripheral CD4+ cell counts (median: 9, range: 1-107) and a higher burden of cryptococcus than patients without HIV. There were no statistically significant differences in serum CRP level and other cerebrospinal fluid parameters between patients with HIV and without HIV. The in-hospital mortality was 10%, and recurrence of cyptococcal meningitis was observed in 3 patients with HIV and this occurred within 5 months of the first episode. Conclusion Cryptococcal meningitis is fatal without treatment, therefore, rapid recognition of symptoms such as fever and headache and diagnosis is required to decrease the mortality. Recurrence of meningitis after treatment should carefully be followed up, especially in advanced HIV patients.

We report a retrospectively identified fatal case of severe fever with thrombocytopenia syndrome (SFTS) in South Korea from 2012. SFTS virus was isolated from the stored blood of the patient. Phylogenetic analysis revealed this isolate was closely related to SFTS virus strains from China and Japan.

Background/Aims: Increasing incidences of hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV)-infected men who have sex were reported in the United States and Europe. However, few studies regarding the epidemiology of HCV infection in HIV-infected patients in Asian countries have been reported. Methods: To determine the prevalence and incidence of HCV infection in HIV-infected patients, a retrospective cohort study was conducted. All HIV-infected patients who visited a tertiary care hospital in Korea from 2000 to 2013 were identified. Patients with ≥ 1 HCV antibody (Ab) test were included and observed until December 2014. Results: Among 996 HIV-infected patients, 790 patients (79%) had baseline HCV Ab tests and 41 (5.2%) were positive at baseline and four at follow-up. Experience of injecting drug use (IDU; adjusted odds ratio, 16.20; 95% confidence interval [CI], 1.56 to 167.89; p < 0.01) was significantly associated with prevalent HCV infection. Conversion to HCV Ab positivity was observed in four of 384 included patients, with an incidence rate of 2.22 (95% CI, 0.60 to 5.80)/1,000 person-years (PYs); 164.89 (95% CI, 34.00 to 481.88)/1,000 PYs in patients with IDU, and 1.40 (95% CI, 0.35 to 7.79)/1,000 PYs in men who have sex with men who denied IDU. There was no significant increase in incidence rate of HCV in HIV-infected patients from 2009 to 2014 (p = 0.119). Among 19 patients who were positive for HCV RNA, genotype 1b (73%) was the most common following 2a/2c (20%). Conclusions: IDU was an independent risk factor for prevalent HCV infection. Prevalence of HCV infection was low and incidence of HCV infection was not significantly increased in HIV-infected patients in South Korea.

Poor retention in care (RIC) is associated with higher antiretroviral therapy (ART) failure and worse survival. Identifying high risk patients for poor RIC is important for targeted intervention. A retrospective cohort study was conducted at a tertiary care hospital in Korea. HIV-infected patients initiating ART during 2002-2008 were included. 5 year-RIC was measured by hospital visit constancy (HVC) at 5 years after initiating ART. Among 247 enrolled patients, 179 (72.5%) remained in care, 20 (8.1%) were transferred to other hospitals, 9 (3.6%) died and 39 (15.8%) were lost to follow-up. We compared the demographic, psychosocial, and clinical characteristics between the groups with 100% HVC (n = 166, 67.2%) and ≤ 50% HVC (n = 33, 13.4%). In multivariable analysis, ART-starting age ≤ 30 years (odds ratio [OR] 4.08 vs. > 50; 95% confidence interval [CI] 1.10-15.15, P = 0.036), no non-HIV related comorbidity (OR 2.94 vs. comorbidity ≥ 1; 95% CI 1.02-8.49, P = 0.046), baseline CD4 cell count > 300 cells/μL (OR 3.58 vs. ≤ 200; 95% CI 1.33-9.65, P = 0.012) were significant predictable factors of poor RIC. HIV/AIDS care-givers should pay attention to young patients with higher baseline CD4 cell counts and no non-HIV related comorbidity., Graphical Abstract

Successful empirical therapy of Staphylococcus aureus infections requires the ability to predict methicillin resistance. Our aim was to identify predictors of methicillin resistance in community-onset (CO) invasive S. aureus infections. Sixteen hospitals across Korea participated in this study from May to December 2012. We prospectively included cases of S. aureus infection in which S. aureus was isolated from sterile clinical specimens ≤ 72 hours after hospitalization. Clinical and epidemiological data were gathered and compared in methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) cases. Community-associated (CA) infections were defined as in previous studies. In total, there were 786 cases of community-onset S. aureus infection, 102 (13.0%) of which were CA-MRSA. In addition to known risk factors, exposure to 3rd generation cephalosporins in the past 6 months [odds ratio (OR), 1.922; 95% confidence interval (CI), 1.176-3.142] and close contact with chronically ill patients in the past month (OR, 2.647; 95% CI, 1.189-5.891) were independent risk factors for MRSA infection. However, no clinical predictors of CA-MRSA were identified. Methicillin resistance, CO infection, and appropriateness of empirical antibiotics were not significantly related to 30-day mortality. MRSA infection should be suspected in patients recently exposed to 3rd generation cephalosporins or chronically-ill patients. There were no reliable predictors of CA-MRSA infection, and mortality was not affected by methicillin resistance.

Voriconazole is the drug of choice for invasive aspergillosis. We describe three patients who presented with severe hyponatremia after the initiation of voriconazole treatment. One patient expired while the other two patients recovered after a dose adjustment or discontinuation of the antifungal. The voriconazole trough levels were checked in all and two were elevated. These findings mandate monitoring electrolyte levels during voriconazole therapy.

Although the incidence of non-Aspergillus filamentous fungal infections has increased, there is little data regarding the correlation between the results of histologic analysis and those of microbiologic culture in clinical practice. We investigated the results of fungal cultures inoculated with tissue specimens that had been found to have fungal hyphae on histologic examination at a university-affiliated tertiary care hospital. Culture studies were requested for microbiologic diagnosis for 122 (31%) of 393 patients with histologic evidence of the presence of filamentous fungal infections. In 53 (43.4%) out of the 122 specimen, fungi were recovered and identified. In 9 (17%) out of the 53 cases, the histology and culture results were discordant. These data serve to remind physicians of the need for obtaining fungus cultures in these types of cases.

Background. Blood levels of voriconazole, a first line therapy for invasive aspergillosis, may correlate with adverse events and treatment response. However, no randomized controlled studies have been conducted to evaluate the clinical utility of routine therapeutic drug monitoring (TDM) of voriconazole. This study aimed to determine whether routine TDM of voriconazole reduces drug adverse events or improves treatment response in invasive fungal infections. Methods. This was a randomized, assessor-blinded, controlled, single center trial. One hundred ten adult patients were randomly assigned to TDM or non-TDM groups. In the TDM group, voriconazole dosage was adjusted (target range, 1.0–5.5 mg/L) according to the serum trough level measured on the fourth day after initiation of voriconazole. The non-TDM group received a fixed, standard dosage. Voriconazole-related adverse events were monitored, and treatment response was assessed three months after the initiation of therapy. Results. Baseline characteristics including the CYP2C19 genotype were comparable between the two groups. While the incidence of adverse events was not different between the TDM group and the non-TDM group (both 42%; P= .97), the proportion of voriconazole discontinuation due to adverse events was significantly lower in the TDM group than in the non-TDM group (4% vs 17%; P= .02). A complete or partial response was observed in 81% (30 of 37) of patients in the TDM group compared to 57% (20 of 34) in the non-TDM group (P= .04). Conclusions. Routine TDM of voriconazole may reduce drug discontinuation due to adverse events and improve the treatment response in invasive fungal infections. Clinical Trial Registration. NCT00890708.

Background/Aims: To compare the frequency of metabolic syndrome (MetS) and magnitude of insulin resistance, measured by the homeostatic model assessment of insulin resistance (HOMA-IR), between South Korean women with rheumatoid arthritis (RA) and healthy subjects, and to evaluate risk factors for MetS and increased HOMA-IR in patients with RA. Methods: In a cross-sectional setting, 84 female patients with RA and 109 agematched healthy female subjects were consecutively recruited at a universityaffi liated rheumatology center in South Korea. MetS was defined according to the Third Report of the National Cholesterol Education Program`s Adult Treatment Panel (NCEP-ATP III) 2004 criteria. Results: The frequency of MetS did not differ significantly between patients with RA (19%) and healthy subjects (15.6%, p = 0.566), although patients with RA had a higher HOMA-IR compared with healthy subjects (p < 0.001). Patients with RA met the NCEP-ATP III 2004 criteria for high blood pressure more often than healthy subjects (44% vs. 19.3%, p < 0.001), and low high density lipoprotein cholesterol was more prevalent in healthy subjects (33%) than in patients with RA (14.3%, p = 0.004). Although no obvious risk factors for the presence of MetS were identified in patients with RA, higher serum C-reactive protein and disease activity score assessed using the 28-joint count for swelling and tenderness-erythrocyte sedimentation rate significantly contributed to a higher HOMA-IR. Conclusions: Despite their increased insulin resistance, South Korean womenwith RA did not have a significantly higher frequency of MetS compared with that in healthy subjects.

Limited data on the clinical outcome of vancomycin treatment compared with that of beta-lactam treatment in patients with methicillin-susceptible Staphylococcus aureus bacteremia (MSSA-B) are available. We used different and complementary approaches: (i) a retrospective cohort study using a propensity score to adjust for confounding by treatment assignment and (ii) a matched case-control study. Of all patients with S. aureus bacteremia (SAB) in two university-affiliated hospitals over a 7-year period, 294 patients with MSSA-B were enrolled in the cohort study. The cases for the case-control study were defined as patients who received vancomycin treatment for MSSA-B; the controls, who were patients that received beta-lactam treatment for MSSA-B, were selected at a 1:2 (case:control) ratio according to the objective matching scoring system and the propensity score system. In the cohort study, SAB-related mortality in patients with vancomycin treatment (37%, 10/27) was significantly higher than that in those with beta-lactam treatment (18%, 47/267) ( P = 0.02). In addition, multivariate analysis revealed that vancomycin treatment was associated with SAB-related mortality when independent predictors for SAB-related mortality and propensity score were considered (adjusted odds ratio of 3.3, 95% confidence interval of 1.2 to 9.5). In the case-control study using the objective matching scoring system and the propensity score system, SAB-related mortality in case patients was 37% (10/27) and in control patients 11% (6/54) ( P < 0.01). Our data suggest that vancomycin is inferior to beta-lactam in the treatment of MSSA-B.

Background We estimated the nationwide burden of nosocomial S. aureus bloodstream infection (SA-BSI), a major cause of nosocomial infection, in South Korea. Methods To evaluate the nationwide incidence of nosocomial SA-BSI, cases of SA-BSI were prospectively collected from 22 hospitals with over 500 beds over 4?months. Data on patient-days were obtained from a national health insurance database containing the claims data for all healthcare facilities in South Korea. The additional cost of SA-BSI was estimated through a matched case?control study. The economic burden was calculated from the sum of the medical costs, the costs of caregiving and loss of productivity. Results Three hundred and thirty nine cases of nosocomial SA-BSI were included in the study: 254 cases of methicillin-resistant SA-BSI (MRSA-BSI) and 85 cases of methicillin-susceptible SA-BSI (MSSA-BSI). Death related to BSI occurred in 81 cases (31.9%) of MRSA-BSI and 12 cases (14.1%) of MSSA-BSI. The estimated incidence of nosocomial MRSA-BSI was 0.12/1,000 patient-days and that of nosocomial MSSA-BSI, 0.04/1,000 patient-days. The estimated annual cases of nosocomial BSI were 2,946 for MRSA and 986 for MSSA in South Korea. The additional economic burden per case of nosocomial SA-BSI was US $20,494 for MRSA-BSI and $6,914 for MSSA-BSI. Total additional annual cost of nosocomial SA-BSI was $67,192,559. Conclusion In view of the burden of nosocomial SA-BSI, a national strategy for reducing nosocomial SA-BSI is urgently needed in South Korea. Electronic supplementary material The online version of this article (doi:10.1186/s12879-014-0590-4) contains supplementary material, which is available to authorized users.