Increasing Malaria Parasite Clearance Time after Chloroquine Therapy, South Korea, 2000-2016.

We reviewed the clinical efficacy of chloroquine for Plasmodium vivax malaria, the changing trend of parasite clearance time, and fever clearance time during 2000-2016 in South Korea. Median parasite clearance time and fever clearance time increased significantly over the study period. Chloroquine was mostly underdosed when used to treat P. vivax malaria.

Severe vivax malaria in the Republic of Korea during the period 2000 to 2016.

BACKGROUND: There has been a marked increase in the reporting of confirmed vivax malaria cases in certain geographical areas. This study investigated cases of severe vivax malaria in the Republic of Korea. METHODS: We retrospectively reviewed the medical records of adult patients diagnosed with vivax malaria in the Republic of Korea during the period 2000 to 2016. Diagnosis was made using the World Health Organization criteria, with the exception of parasite density. RESULTS: Among 1366 malaria cases, 255 (18.7%) were classified as severe vivax malaria, and 46 (3.4%) required intensive care. None of patients died of malaria. Patients with severe vivax malaria were older and had more comorbidity. The enrollment periods were classified into three groups, 2000 to 2005 (506 cases), 2006 to 2010 (696 cases), and 2011 to 2016 (304 cases). Malaria cases decreased from 2011 to 2016, but severe malaria cases increased significantly over time (14.3%, 20.1%, and 22.8%, p = 0.003). Common severe manifestations were shock (45.6%) and jaundice (43.1%). CONCLUSIONS: Cases of severe malaria increased, and shock and jaundice were the predominant findings of severe vivax malaria in the Republic of Korea.

Examination of Hospital Workers' Emotional Responses to an Infectious Disease Outbreak: Lessons From the 2015 MERS Co-V Outbreak in South Korea.

ABSTRACTHospital workers are critical for a successful response to an infectious disease outbreak and for preventing disease transmission to the community. Therefore, hospital crisis management should implement efforts to improve hospital workers' preparedness in responding to public health emergencies caused by infectious diseases. Traditionally, preparedness and skill of hospital workers have been emphasized, but awareness of the importance of the emotional mindset of hospital workers in dealing with disease outbreaks has only recently increased; therefore, empirical approaches to examining emotional responses of hospital workers has been limited. This study analyzed qualitative data of the 2015 Middle East Respiratory Syndrome outbreak in South Korea. In particular, negative emotions and stress experienced by hospital workers who treated patients were characterized, as were the events that triggered such experiences. These events were categorized into four themes (eg, Mistake, Missing, Delay Due to Communication Failure). Identifying events that trigger negative emotions in hospital workers has important implications for hospitals' management guidance in relation to an infectious disease outbreak. (Disaster Med Public Health Preparedness. 2019;13:504-510).

Emergence of Daptomycin-Nonsusceptible Methicillin-Resistant Staphylococcus aureus Clinical Isolates Among Daptomycin-Naive Patients in Korea.

This study was conducted to assess emergence of daptomycin-nonsusceptible (DAP-NS) phenotype in DAP-naive patients with invasive Staphylococcus aureus (ISA) infections in Korea. A total of 208 S. aureus clinical isolates were selected from a previous prospective study on ISA infections and evaluated for DAP-NS. Although DAP has never been introduced in Korea, five DAP-NS S. aureus strains (2.4%) were identified among 208 S. aureus strains collected from ISA infections. The DAP-NS phenotype was observed only in methicillin-resistant S. aureus (MRSA) strains, but not in methicillin-susceptible S. aureus strains. One DAP-NS MRSA strain belonged to sequence type 72 (ST72) and four were ST5 MRSA strains, three of which were heteroresistant vancomycin (VAN)-intermediate S. aureus. All these five DAP-NS MRSA strains were from healthcare-associated infections without prior exposure to VAN within 30 days. While the ST72 MRSA strain exhibited DAP-NS phenotype via charge repulsion mechanism, four ST5 DAP-NS S. aureus strains had charge-independent DAP-NS mechanism. None of the five DAP-NS strains displayed significant increase in cell wall thickness, indicating that altered cell wall thickness was not associated with the observed DAP-NS phenotype.

Impact of Vancomycin MIC on Treatment Outcomes in Invasive Staphylococcus aureus Infections.

There are conflicting data on the association of vancomycin MIC (VAN-MIC) with treatment outcomes in Staphylococcus aureus infections. We investigated the relationship between high VAN-MIC and 30-day mortality and identified the risk factors for mortality in a large cohort of patients with invasive S. aureus (ISA) infections, defined as the isolation of S. aureus from a normally sterile site. Over a 2-year period, 1,027 adult patients with ISA infections were enrolled in 10 hospitals, including 673 (66%) patients with methicillin-resistant S. aureus (MRSA) infections. There were 200 (19.5%) isolates with high VAN-MIC (≥1.5 mg/liter) by Etest and 87 (8.5%) by broth microdilution (BMD). The all-cause 30-day mortality rate was 27.4%. High VAN-MIC by either method was not associated with all-cause 30-day mortality, and this finding was consistent across MIC methodologies and methicillin susceptibilities. We conclude that high VAN-MIC is not associated with increased risk of all-cause 30-day mortality in ISA infections. Our data support the view that VAN-MIC alone is not sufficient evidence to change current clinical practice.

Clinical Presentation and Outcomes of Middle East Respiratory Syndrome in the Republic of Korea.

BACKGROUND: From May to July 2015, the Republic of Korea experienced the largest outbreak of Middle East respiratory syndrome (MERS) outside the Arabian Peninsula. A total of 186 patients, including 36 deaths, had been diagnosed with MERS-coronavirus (MERS-CoV) infection as of September 30th, 2015. MATERIALS AND METHODS: We obtained information of patients who were confirmed to have MERS-CoV infection. MERS-CoV infection was diagnosed using real-time reverse-transcriptase polymerase chain reaction assay. RESULTS: The median age of the patients was 55 years (range, 16 to 86). A total of 55.4% of the patients had one or more coexisting medical conditions. The most common symptom was fever (95.2%). At admission, leukopenia (42.6%), thrombocytopenia (46.6%), and elevation of aspartate aminotransferase (42.7%) were observed. Pneumonia was detected in 68.3% of patients at admission and developed in 80.8% during the disease course. Antiviral agents were used for 74.7% of patients. Mechanical ventilation, extracorporeal membrane oxygenation, and convalescent serum were employed for 24.5%, 7.1%, and 3.8% of patients, respectively. Older age, presence of coexisting medical conditions including diabetes or chronic lung disease, presence of dyspnea, hypotension, and leukocytosis at admission, and the use of mechanical ventilation were revealed to be independent predictors of death. CONCLUSION: The clinical features of MERS-CoV infection in the Republic of Korea were similar to those of previous outbreaks in the Middle East. However, the overall mortality rate (20.4%) was lower than that in previous reports. Enhanced surveillance and active management of patients during the outbreak may have resulted in improved outcomes.

Characteristics of invasive Staphylococcus aureus infections in three regions of Korea, 2009-2011: a multi-center cohort study.

BACKGROUND: Despite the importance of invasive Staphylococcus aureus (ISA) infection, its overall burden in non-selected populations has only been defined in a small number of studies in Europe and North America. To define the characteristics of ISA infections in Korea, we conducted a multi-center cohort study to estimate population-based incidence rates. METHODS: We conducted a multicenter prospective cohort study at nine university-affiliated active-surveillance core centers (ASCs) in three regions of Korea. To cover all available clinical microbiologic laboratories, we classified the laboratories in these regions into three groups according to their clinical environment as: 1) Nine ASCs, 2) Five major commercial laboratories and 3) Forty-four acute-care hospital-affiliated microbiology laboratories. We requested all the laboratories to report prospectively their numbers of cases of S. aureus isolated from normally sterile sites. Detailed clinical information was collected about the cases in the nine ASCs. RESULTS: From 1 July 2009 to 30 June 2011, a total of 1,198 cases of ISA infection were identified at the nine ASCs, including 748 (62%) methicillin-resistant S. aureus (MRSA) infections. Most (81%) ISA infections were healthcare-associated (HCA): 653 (55%) hospital-onset and 322 (27%) community-onset. 223 (19%) were community-associated infections. The most common primary diagnosis was catheter-associated infection (225 cases, 19%). Respiratory tract infection (160, 13%), skin & soft tissue (152, 13%) and bone & joint infections (120, 10%) were also common. 30-day and 12-week mortality rates were 25.6% (262/1,024) and 36.5% (314/860), respectively. Complications, including metastatic infection within 12 weeks, occurred in 17.8% of ISA infections. The most common site of metastatic infection was the lung (9.8%, 84/860). Based on the total of 2,806 observed cases of ISA infection, estimated annual rates of ISA and invasive MRSA infections were 43.3 and 27.7 per 100,000 populations, respectively. CONCLUSIONS: Our data provide important information about the clinical characteristics of ISA infections. We estimate that over 21,000 ISA infections and 13,000 invasive MRSA infections occurred in Korea in 2010.

Lack of effect of dexamethasone on growth of Orientia tsutsugamushi Gilliam in mouse L929 cells.

PURPOSE: Previous studies and our own clinical experience suggest that concurrent corticosteroid treatment for severe rickettsial disease with multiorgan failure may improve the clinical course or reduce mortality. However, the use of corticosteroids as adjunctive treatment for rickettsial diseases is controversial. We attempted to determine the influences of corticosteroid on the growth of Orientia tsutsugamushi in vitro to justify and evaluate the clinical applicability of corticosteroid in rickettsial disease. MATERIALS AND METHODS: L929 cells were infected with Orientia tsutsugamushi Gilliam. Dexamethasone was added to the cells at final concentrations of 10¹ and 107 pg/mL. Cultures were incubated at 35°C and processed for flow cytometry on the 6th day after addition of dexamethasone. RESULTS: Observation on the 6th day after treatment with dexamethasone in infected cultures revealed that there was no difference in fluorescence intensity among the treatment wells. Treatment of the cells with dexamethasone at concentrations of 10¹ and 107 pg/mL showed no influence on the growth of Orientia tsutsugamushi. CONCLUSION: Our results to show that isolated corticosteroid does not enhance the replication of Orientia tsutsugamushi in vitro. Concurrent use of anti-inflammatory or immunosuppressive doses of corticosteroids in conjunction with antibiotics may not have detrimental effects on the course of scrub typhus.

A prediction rule to identify severe cases among adult patients hospitalized with pandemic influenza A (H1N1) 2009.

The purpose of this study was to establish a prediction rule for severe illness in adult patients hospitalized with pandemic influenza A (H1N1) 2009. At the time of initial presentation, the baseline characteristics of those with severe illness (i.e., admission to intensive care unit, mechanical ventilation, or death) were compared to those of patients with non-severe illnesses. A total of 709 adults hospitalized with pandemic influenza A (H1N1) 2009 were included: 75 severe and 634 non-severe cases. The multivariate analysis demonstrated that altered mental status, hypoxia (PaO(2)/FiO(2) ≤ 250), bilateral lung infiltration, and old age (≥ 65 yr) were independent risk factors for severe cases (all P < 0.001). The area under the ROC curve (0.834 [95% CI, 0.778-0.890]) of the number of risk factors were not significantly different with that of APACHE II score (0.840 [95% CI, 0.790-0.891]) (P = 0.496). The presence of ≥ 2 risk factors had a higher sensitivity, specificity, positive predictive value and negative predictive value than an APACHE II score of ≥ 13. As a prediction rule, the presence of ≥ 2 these risk factors is a powerful and easy-to-use predictor of the severity in adult patients hospitalized with pandemic influenza A (H1N1) 2009.

Parasitemia characteristics of Plasmodium vivax malaria patients in the Republic of Korea.

Parasitemia characteristics of Plasmodium vivax malaria in temperate regions may differ from those in tropical zones. However, most parasitological and clinical features of P. vivax malaria have been investigated in the latter. In this study, we investigated 383 malaria patients to clarify the parasitemia characteristics of a P. vivax strain in the Republic of Korea (ROK). The mean parasitemia (8,396/µL) was less than half of tropical P. vivax malaria, and multiple invasions of erythrocytes were not rare (53.5% of the patients, 2.4% of the total investigated RBCs), but less than the observations in tropical zones. The intervals between the first symptom onset and diagnosis were significantly longer in gametocyte (+) patients than in gametocyte (-) patients. Only half of the total patients had both genders of gametocytes (191 of 353), and the male gametocyte density (169/µL) was lower than that of P. vivax strains of a previous study. Multiple invasions of erythrocytes and gametocytemia were coincident factors of the degree of anemia in P. vivax malaria. The present findings demonstrate the P. vivax strain in ROK reveals relatively low parasitemia and low male to female gametocyte ratio. The low ratio may be related with low transmission efficacy.

Extensively drug-resistant Acinetobacter baumannii: risk factors for acquisition and prevalent OXA-type carbapenemases--a multicentre study.

In this study, we investigated the risk factors for and carbapenem resistance mechanisms of extensively drug-resistant Acinetobacter baumannii (XDR-AB). Isolates of XDR-AB were collected from seven tertiary care hospitals in South Korea. A case-control study for risk factor analysis was performed and the presence of the metallo-ß-lactamase (MBL) and OXA genes was examined. The control group consisted of adult inpatients receiving care from the same hospital. XDR-AB were isolated from 26 patients who were studied for risk factor analysis. Third-generation cephalosporin use [odds ratio (OR)=9.6, 95% confidence interval (CI) 1.3-171.3; P=0.02] and Acute Physiology and Chronic Health Evaluation (APACHE) II score (OR=1.2, 95% CI 1.1-1.5; P=0.004) were identified as risk factors for acquisition of XDR-AB. Pulsed-field gel electrophoresis (PFGE) showed clonal epidemic isolates in hospitals. MBLs were not detected, and all 30 XDR-AB isolates had upregulated OXA-type carbapenemase genes. These results suggest that third-generation cephalosporin use and disease severity are associated with XDR-AB acquisition amongst typical adult inpatients. This study also points to intrahospital spread of XDR-AB. Upregulated OXA-type carbapenemases are prevalent in XDR-AB founded in South Korean hospitals.

Short report: chloroquine-resistant Plasmodium vivax in the Republic of Korea.

The number of Plasmodium vivax malaria patients in the Republic of Korea and North Korea since the re-emergence of malaria in 1993 is estimated to be approximately one million. To cope with this situation, the Army of the Republic of Korea has performed chemoprophylaxis with hydroxychloroquine and primaquine since 1997. The cumulative number of soldiers in the Army of the Republic of Korea given chemoprophylaxis exceeded 1.4 million by 2007. Extensive chemoprophylaxis contributed to preventing a rapid increase of malaria patients in the Army of the Republic of Korea, but increased the possibility of the occurrence of chloroquine (CQ)-resistant P. vivax strains. In this study, treatment responses of P. vivax malaria patients in the Republic of Korea monitored during 2003-2007, and CQ resistance was confirmed in 2 of 484 enrolled patients. Our results are the first report of CQ-resistant P. vivax in a temperate region of Asia. Continuous surveillance is warranted to monitor the change in CQ resistance frequency of P. vivax in the Republic of Korea.

[Evaluation of usefulness of the panel test composed of malaria non-specific tests as a surrogate marker].

BACKGROUND: Although malaria-specific antibody or antigen test is useful for the diagnosis of malaria infection, its cost-effectiveness has to be concerned in the area where malaria prevalence is very low. We created a panel test composed of malaria non-specific parameters, namely hematology autoanalyzer-derived results with or without addition of HDL-cholesterol data, and evaluated its usefulness in comparison with malaria-specific antibody test. METHODS: For 395 patients tested for malaria smear, the hematology parameters such as platelet count, NRBC (%) and VCS (volume, conductivity, scattering) parameters of WBC, and HDL-cholesterol data were analyzed. Statistical significance of each parameter and that of panel test with or without addition of HDL-cholesterol were evaluated. RESULTS: Malaria antibody test showed sensitivity of 97.1% and specificity of 99.1%. Each parameter of platelet count, NRBC (%), D parameter and HDL-cholesterol showed sensitivity of 86.8%, 41.2%, 81.8%, and 70.6%, and specificity of 85.9%, 96.3%, 72.3%, and 81.7%, respectively. Panel test without including HDL-cholesterol showed sensitivity of 91.2% and specificity of 81.6%, and that including HDL-cholesterol showed sensitivity of 91.2% and specificity of 86.2%. CONCLUSIONS: The malaria non-specific panel test composed of hematology autoanalyzer-derived parameters showed relatively good, but slightly lower sensitivity than that of malaria-specific antibody test. It might be used as a screening test for the diagnosis of malaria infection, and addition of HDL cholesterol improved little the usefulness of the panel test.

Increasing vancomycin susceptibility in vancomycin resistant enterococci by vanH promoter and ddl transformation.

OBJECTIVES: In vancomycin resistant enterococci (VRE) the vanHAXYZ genes encode a new pathway of enzymes to produce d-alanyl-d-lactate. We investigated the effect of vanH promoter and ddl gene transformation on vancomycin susceptibility in a vanA phenotype of Enterococcus faecalis. METHODS: To construct plasmid pJW1, the vanH promoter was cloned to plasmid pAM401. Plasmid pJW2 was constructed by cloning the ddl gene into pAM401. To construct pJW3, the ddl gene was ligated downstream of the vanH promoter of the plasmid pJW1. The competent VRE was transformed with pJW1, pJW2 and pJW3 using electroporation. The minimal inhibitory concentration (MIC) of vancomycin for VRE and transformed E. faecalis was determined using the broth dilution method. The expression of the vanA and ddl gene of VRE and transformed E. faecalis was evaluated by RT PCR. RESULTS: The transformation of the vanH promoter reduced the vancomycin MIC of VRE. In VRE and transformed E. faecalis, the vanA and ddl genes were expressed. CONCLUSIONS: This study presents a way of altering high-level vancomycin resistance with gene transformation in enterococci. In the future, development of an effective gene delivery system will contribute to the design of new modalities that will help overcome the limitations of antimicrobial therapy.

Epidemiology and clinical features of HIV infection/AIDS in Korea.

HIV infection/AIDS shows characteristic epidemiological and clinical patterns according to the region, country, and race. The epidemiological and clinical patterns of HIV infection/ AIDS in Korea was investigated by retrospectively analyzing the medical records of 176 HIV-infected persons who visited two major referral hospitals of AIDS in Korea from 1985 to April 2000. The most common transmission route was heterosexual contact (52.3%), followed by homosexual contact (23.9%). Among the opportunistic diseases, candidiasis was the most prevalent (21.6%), followed by Pneumocystis carinii pneumonia (15.9%), tuberculosis (12.5%), and CMV infection (9.1%). The most common initial AIDS-defining opportunistic disease was tuberculosis (33.3%). The most common causes of death were tuberculosis (25.7%) and Pneumocystis carinii pneumonia (25.7%). This study describes the epidemiological and clinical patterns of HIV infection/AIDS in Korea, which not only enables us to accurately understand HIV infection/ AIDS in this country, but eventually to aid in establishing effective preventive measures and treatment guidelines in Korea.