Adverse Drug Events Associated With Remdesivir in Real-World Hospitalized Patients With COVID-19, Including Vulnerable Populations: A Retrospective Multicenter Study

BACKGROUND

Remdesivir is a US Food and Drug Administration-approved drug for coronavirus disease 2019 (COVID-19). Clinical trials were conducted under strictly controlled situations for a selected population, and their reported adverse events may not fully represent conditions in real-world patients. We aimed to estimate the incidence of adverse drug events (ADEs) associated with remdesivir in hospitalized patients with COVID-19, including vulnerable subpopulations, such as those with impaired renal or hepatic function and pregnant women.

METHODS

This retrospective observational study included hospitalized patients with confirmed COVID-19 treated with remdesivir between January and December 2021 at ten hospitals. ADEs and severe ADEs (Common Toxicity Criteria for Adverse Events grade ≥ 3) were operationally defined and analyzed through laboratory investigations. The incidence of ADEs was compared with that of each matched control in subpopulations with renal or hepatic impairment and pregnant women.

RESULTS

Among 2,140 patients, 1,416 (66.2%) and 295 (13.8%) experienced at least one ADE and severe ADE, respectively. The most frequent ADE was 'hepatic injury' (42.9%), followed by anemia (27.6%). The most common severe ADEs were 'hypokalemia' (5.3%), 'hepatic injury' (2.9%), and 'anemia' (3.6%). There was no significant difference in the incidence of ADEs in patients relative to their respective matched-control groups, including those with renal impairment (80.0% vs. control 71.8%, P = 0.063), hepatic impairment (70.4% vs. control 75.0%, P = 0.623) and pregnant women (78.6% vs. control 63.7%, P = 0.067). However, severe ADE incidence was significantly higher in patients with renal impairment (40.8% vs. 16.0%, P < 0.001). The most common severe ADEs in those were 'anemia' (15.3%), 'hypokalemia' (10.5%), and 'thrombocytopenia' (8.9%). There was no statistically significant difference in the incidence of severe ADEs in patients with hepatic impairment or in pregnancy (P = 0.230; P = 0.085).

CONCLUSION

A significant proportion of patients with COVID-19 treated with remdesivir experienced ADEs and severe ADEs. Given the high incidence of severe ADEs, caution is required in patients with renal impairment. Further studies are needed to investigate ADEs in pregnant women and patients with hepatic impairment.

Comparison of Cefazolin/Metronidazole to Ampicillin/Sulbactam as Preoperative Antibiotics in Colorectal Surgery: A Retrospective, Single-Center Cohort Study

AIM

The use of prophylactic antibiotics prior to colorectal surgery reduces surgical site infections. Cefazolin and metronidazole are used as a standard regimen. Ampicillin/sulbactam may be an alternative, but current data are limited. We compared the efficacy of ampicillin/sulbactam with cefazolin and metronidazole as prophylactic antibiotics.

METHODS

Patients who underwent colorectal surgery at Inha University Hospital between 2010 and 2020 were treated prophylactically with cefazolin and metronidazole or ampicillin/sulbactam, and observed for 30 days following surgery. The primary outcome was surgical site infections. The secondary outcomes were deep/organ infections and the need for drainage.

RESULTS

SSIs occurred in 2.6% (17/646) of the ampicillin/sulbactam group, whose rate was not inferior to the occurrence in the group receiving cefazolin and metronidazole (3.8%, 21/556). There was no significant difference between the two groups in the secondary outcomes.

CONCLUSIONS

Compared to the cefazolin and metronidazole combination, ampicillin/sulbactam is not inferior as a preoperative prophylactic antibiotic regimen for colorectal surgery.

Antibiotic Combination Therapy for Severe Scrub Typhus: Is It Necessary?

Scrub typhus can be adequately treated with doxycycline or azithromycin unless it is treated too late. Such cases present as severe scrub typhus, and their treatment remains a challenging problem. In this article, we briefly review the literature on the treatment of scrub typhus and the limitations of the combination of doxycycline and azithromycin. Several options are suggested for further study in the treatment of severe scrub typhus (such as encephalitis, myocarditis, and pneumonia), including dose escalation of doxycycline, the adjuvant use of steroids, the selective use of beta-lactam antibiotics, and the use of tigecycline.

Adverse events of a third dose of BNT162b2 mRNA COVID-19 vaccine among Korean healthcare workers

Due to the urgency of controlling the coronavirus disease 2019 pandemic, coronavirus disease 2019 messenger ribonucleic acid (mRNA) vaccines have been expeditiously approved and introduced in several countries without sufficient evaluation for adverse events. We analyzed adverse events among Korean healthcare workers who received all 3 doses of the BNT162b2 mRNA vaccine. This survey was conducted among hospital workers of Inha University Hospital who had received the BNT162b2 mRNA vaccine for their first, second, third rounds, and using a diary card. The surveyed adverse events included local (redness, edema, and injection site pain) and systemic (fever, fatigue, headache, chill, myalgia, arthralgia, vomiting, diarrhea, pruritis, and urticaria) side effects and were divided into 5 grades (Grade 0 = none - Grade 4 = critical). Based on adverse events reported at least once after any of the 3 doses, the most common systemic adverse reactions were chills and headache (respectively, 62.6%, 62.4%), followed by myalgia (55.3%), arthralgia (53.4%), fatigue (51.6%), pruritus (38.1%), and fever (36.5%). The frequency and duration of adverse events were significantly greater in women (P < .05) than men. Except for redness, pruritus, urticaria, and most adverse reactions had a higher rate of occurrence after the third dose in subjects who also had reactions with the second dose. However, grade 4 adverse events did occur with the third dose in some patients, even if there were no side effects with the first and second doses. Adverse events experienced with the first and second doses of the BNT162b2 mRNA vaccine in Korean healthcare workers increased the incidence of adverse events at the time of the third dose. On the other hand, grade 4 adverse events could still occur with the third dose even though there were no side effects with the first and second doses.

Optical diffraction tomography and image reconstruction to measure host cell alterations caused by divergent Plasmodium species

Malaria is a life-threatening infectious disease caused by parasites of the genus Plasmodium. Understanding the biological features of various parasite forms is important for the optical diagnosis and defining pathological states, which are often constrained by the lack of ambient visualization approaches. Here, we employ a label-free tomographic technique to visualize the host red blood cell (RBC) remodeling process and quantify changes in biochemical properties arising from parasitization. Through this, we provide a quantitative body of information pertaining to the influence of host cell environment on growth, survival, and replication of P. falciparum and P. vivax in their respective host cells: mature erythrocytes and young reticulocytes. These exquisite three-dimensional measurements of infected red cells demonstrats the potential of evolving 3D imaging to advance our understanding of Plasmodium biology and host-parasite interactions.

Fecal microbiota transplantation can improve cognition in patients with cognitive decline and Clostridioides difficile infection

After fecal microbiota transplantation (FMT) to treat Clostridioides difficile infection (CDI), cognitive improvement is noticeable, suggesting an essential association between the gut microbiome and neural function. Although the gut microbiome has been associated with cognitive function, it remains to be elucidated whether fecal microbiota transplantation can improve cognition in patients with cognitive decline. The study included 10 patients (age range, 63-90 years; female, 80%) with dementia and severe CDI who were receiving FMT. Also, 10 patients (age range, 62-91; female, 80%) with dementia and severe CDI who were not receiving FMT. They were evaluated using cognitive function tests (Mini-Mental State Examination [MMSE] and Clinical Dementia Rating scale Sum of Boxes [CDR-SB]) at 1 month before and after FMT or antibiotics treatment (control group). The patients' fecal samples were analyzed to compare the composition of their gut microbiota before and 3 weeks after FMT or antibiotics treatment. Ten patients receiving FMT showed significantly improvements in clinical symptoms and cognitive functions compared to control group. The MMSE and CDR-SB of FMT group were improved compare to antibiotics treatment (MMSE: 16.00, median, 13.00-18.00 [IQR] vs. 10.0, median, 9.8-15.3 [IQR]); CDR-SB: 5.50, median, 4.00-8.00 [IQR]) vs. 8.0, median, 7.9-12.5, [IQR]). FMT led to changes in the recipient's gut microbiota composition, with enrichment of Proteobacteria and Bacteroidetes. Alanine, aspartate, and glutamate metabolism pathways were also significantly different after FMT. This study revealed important interactions between the gut microbiome and cognitive function. Moreover, it suggested that FMT may effectively delay cognitive decline in patients with dementia.

The effect of Epstein-Barr virus viremia on the progression to severe COVID-19

Epstein-Barr virus (EBV) is frequently reactivated by coronavirus 2019 (COVID-19), and a high incidence of EBV viremia has been reported in patients with severe COVID-19. However, the impact of EBV viremia on progression to severe COVID-19 is unclear. Therefore, we conducted a study to evaluate the effect of EBV on COVID-19 progression.We investigated EBV viremia at the time of admission in COVID-19 patients hospitalized between February 1, 2020, and April 11, 2021. A cross-sectional study was performed to compare the severity of COVID-19 according to the presence or absence of EBV viremia. However, since it is difficult to analyze the influence of EBV viremia on COVID-19 progression with cross-sectional studies, a retrospective cohort study, limited to patients with mild COVID-19, was additionally conducted to observe progression to severe COVID-19 according to the presence or absence of EBV viremia.Two hundred sixty-nine COVID-19 patients were tested for EBV viremia. In a cross-sectional study that included patients with both mild and severe COVID-19, the EBV viremia group had more severe pneumonia than the EBV-negative group. However, in the cohort study limited to mild cases (N = 213), EBV viremia was not associated with COVID-19 progression.COVID-19 severity may affect EBV viremia; however, there was no evidence that EBV viremia was a factor in exacerbating pneumonia in patients with mild COVID-19.

Adverse Events with the Pfizer-BioNTech COVID-19 Vaccine among Korean Healthcare Workers

The Pfizer-BioNTech COVID-19 vaccine has shown excellent clinical effectiveness; however, adverse events of the vaccine remain a concern in Korea. We surveyed adverse events in 2498 healthcare workers vaccinated with the Pfizer-BioNTech COVID-19 vaccine at a university hospital. The survey was conducted using a diary card for 7 days following each injection. The questionnaire response rate was 75.1% (1876/2498) for the first dose and 73.8% (1840/2493) for the second dose. Among local reactions, pain was the most commonly reported (84.9% after the first dose and 90.4% after the second dose). After the second dose, two people visited the emergency room due to severe local pain, but no hospitalization or skin necrosis occurred. Among systemic reactions, fatigue was most frequently reported (52.8% after the first dose and 77.0% after the second dose), followed by myalgia (49.0% and 76.1%), headache (28.7% and 59.2%), chills (16.7% and 54.0%), and arthralgia (11.4% and 39.2%). One or more critical adverse events occurred in 0.2% and 0.7% of the vaccinees. Except for urticaria, more adverse events were reported after the second dose than after the first dose. In the future, adverse events should be investigated in older adults, and a future study with a longer observation period should be conducted.

A Profile of Glucose-6-Phosphate Dehydrogenase Variants and Deficiency of Multicultural Families in Korea

Vivax malaria incidence in Korea is now decreased and showing a low plateau. Nowadays, vivax malaria in Korea is expected to be successfully eliminated with anti-malaria chemotherapy, primaquine, and vector control. The glucose-6-phosphate dehydrogenase (G6PD) deficiency is associated with potential hemolytic anemia after primaquine administration. This inborn disorder has a pivotal polymorphism with genetic variants and is the most prevalent X-chromosome-linked disorder. The prevalence of G6PD deficiency was previously reported negligible in Korea. As the population of multicultural families pertaining marriage immigrants and their adolescents increases, it is necessary to check G6PD deficiency for them prior to primaquine treatment for vivax malaria. The prevalence of G6PD variants and G6PD deficiency in multicultural families was performed in 7 counties and 2 cities of Jeollanam-do (Province), Gyeonggi-do, and Gangwon-do. A total of 733 blood samples of multicultural family participants were subjected to test the phenotypic and genetic G6PD deficiency status using G6PD enzyme activity quantitation kit and PCR-based G6PD genotyping kit. The G6PD phenotypic deficiency was observed in 7.8% of male adolescent participants and 3.2% of materfamilias population. Based on the PCR-based genotyping, we observed total 35 participants carrying the mutated alleles. It is proposed that primaquine prescription should seriously be considered prior to malaria treatment.

Altered Influenza Vaccination Coverage and Related Factors in Pregnant Women in Korea from 2007 to 2019

BACKGROUND

Pregnant women are at a high-risk of influenza infection. We have previously reported a low influenza vaccination coverage rate (4.0%) in Korea during the 2006-2007 influenza season. We conducted follow-up studies in 2011-2012 and 2018-2019 to observe changes in influenza vaccination coverage.

METHODS

Women who delivered at Inha University Hospital (Incheon, Korea) in 2011-2012 and 2018-2019 were enrolled in the study. We surveyed the rate of influenza vaccination, perception scores, and related factors through telephonic interviews and compared the results from 2011-2012 and 2018-2019 with those from 2006-2007.

RESULTS

The number of survey respondents was 227 in 2006-2007, 152 in 2011-2012, and 171 in 2018-2019. The rate of vaccination coverage increased from 4.0% in 2006-2007 to 42.0% in 2011-2012 and 59.3% in 2018-2019. Perception scores also increased progressively from 3.8 in 2006-2007 to 4.2 in 2011-2012 and 5.1 in 2018-2019. Physician recommendations for influenza vaccination also increased from 4.8% in 2006-2007 to 36.8% in 2011-2012 and 49.7% in 2018-2019. The most common reason for not getting vaccinated was the lack of awareness of influenza vaccination during pregnancy (36.9%). The perception scores and physician recommendation rates were significantly lower for unvaccinated women (3.87 and 8.4%, respectively) than for vaccinated women (5.14 and 69.1%, respectively).

CONCLUSION

The influenza vaccination coverage rate in pregnant women has increased significantly since our study in 2006-2007. However, further improvement in the coverage rate is needed. There is a need for active and comprehensive publicity and education regarding this issue among physicians and pregnant women.

Effect of a serum lactate monitoring recommendation policy on patients treated with linezolid

Lactic acidosis is one of the most fatal adverse effects of linezolid, an antibiotic used to treat serious infections caused by antibiotic-resistant bacteria. However, the measures to prevent lactic acidosis have not been well established.We performed a retrospective study to analyze the impact of applying a serum lactate monitoring recommendation policy in patients treated with linezolid.Since September 2011, we have recommended inpatient monitoring of serum lactate levels in patients treated with linezolid at our hospital. Patients were divided into two groups according to whether they were seen during the non-recommendation or recommendation periods. The frequency of serum lactate monitoring, linezolid-induced lactatemia, lactic acidosis, critical illness, and death were compared between the two periods.After September 2011, adherence to the recommendation to monitor serum lactate increased from 6.1% to 60.1%. No difference was observed in the incidence of linezolid-induced lactatemia and lactic acidosis between the two periods. However, there was a significant difference in the incidence of linezolid-induced critical illness between the non-recommendation and recommendation periods (3 vs 0 cases, P = .044).In patients treated with linezolid, serum lactate monitoring led to early detection of lactatemia, thus enabling rapid rescue. We recommend regular monitoring of serum lactate in all patients treated with linezolid.

Splenic infarction and infectious diseases in Korea

Background

The spleen contains immune cells and exhibits a pattern of infarction different from other organs; as such, splenic infarction (SI) may provide important clues to infection. However, the nature of the relationship between SI and infectious disease(s) is not well understood. Accordingly, this retrospective study investigated the relationship between SI and infection.

Methods

Hospital records of patients with SI, who visited Inha University Hospital (Incheon, Republic of Korea) between January 2008 and December 2018, were reviewed. Patient data regarding clinical presentation, causative pathogens, risk factors, and radiological findings were collected and analyzed.

Results

Of 353 patients with SI, 101 with infectious conditions were enrolled in this study, and their data were analyzed to identify associations between SI and infection. Ten patients were diagnosed with infective endocarditis (IE), and 26 exhibited bacteremia without IE. Twenty-seven patients experienced systemic infection due to miscellaneous causes (negative result on conventional automated blood culture), including the following intracellular organisms: parasites (malaria [n = 12], babesiosis [n = 1]); bacteria (scrub typhus [n = 5]); viruses (Epstein–Barr [n = 1], cytomegalovirus [n = 1]); and unidentified pathogen[s] (n = 7). Splenomegaly was more common among patients with miscellaneous systemic infection; infarction involving other organs was rare. Thirty-eight patients had localized infections (e.g., respiratory, intra-abdominal, or skin and soft tissue infection), and most (35 of 38) had other risk factors for SI.

Conclusions

In this study, various infectious conditions were found to be associated with SI, and intracellular organisms were the most common causative pathogens. Further studies are needed to examine other possible etiologies and the underlying pathophysiological mechanisms.

Current Status and a Perspective of Mosquito-Borne Diseases in the Republic of Korea

Background: Mosquito-borne diseases in the Republic of Korea have a unique epidemiology due to the rapid improvement in hygiene and economic status, occurrence of four distinct seasons, and separation from North Korea owing to the political situation. Therefore, we aimed to analyze and review the epidemiology of mosquito-borne diseases in Korea. Methods: The incidence and geographical distribution of malaria, Japanese encephalitis (JE), Zika virus infection, chikungunya fever, and dengue fever were investigated using data from the Korean Centers for Disease Control and Prevention. Lymphatic filariasis and West Nile fever, which have rarely been reported in Korea, have also been discussed in this literature review. Results and Conclusions: Malaria disappeared from Korea in 1979, but since its re-emergence in 1993 there has been constant occurrence with local transmission. In Korea, vivax malaria is the only prevailing disease, and the clinically problematic chloroquine resistance has not been reported. The incidence of JE has greatly reduced since the introduction of the national vaccination program for children in 1985. However, the incidence of JE has been increasing recently, especially in adults >40 years of age. Filariasis, which was previously endemic to Jeju Island and the southern coastal area, has not been reported since 2002. Although there are numerous imported cases with increasing overseas travel, there are still no indigenous cases of Zika, chikungunya, and dengue fever reported in Korea. The West Nile virus was isolated from migratory birds, but there has been only one imported human case to date.

Nutritional status of patients with COVID-19

The relationship between immunity and nutrition is well known and its role in coronavirus disease 2019 (COVID-19) is also being paid great attention. However, the nutritional status of COVID-19 patients is unknown. Vitamin B1, B6, B12, vitamin D (25-hydroxyvitamin D), folate, selenium, and zinc levels were measured in 50 hospitalized patients with COVID-19. Overall, 76% of the patients were vitamin D deficient and 42% were selenium deficient. No significant increase in the incidence of deficiency was found for vitamins B1, B6, and B12, folate, and zinc in patients with COVID-19. The COVID-19 group showed significantly lower vitamin D values than the healthy control group (150 people, matched by age/sex). Severe vitamin D deficiency (based on a cut-off of ≤10 ng/dl) was found in 24.0% of the patients in the COVID-19 group and 7.3% in the control group. Among 12 patients with respiratory distress, 11 (91.7%) were deficient in at least one nutrient. However, patients without respiratory distress showed a deficiency in 30/38 cases (78.9%; p =  0.425). These results suggest that a deficiency of vitamin D or selenium may decrease the immune defenses against COVID-19 and cause progression to severe disease. However, more precise and large-scale studies are needed.

Medical management of septic arthritis of sternoclavicular joint: A case report

RATIONALE

Sternoclavicular joint septic arthritis is an unusual disease in healthy adults, and Staphylococcus aureus is the most common causative pathogen. The current treatment of choice is surgery with sternoclavicular joint resection and pectoralis flap closure, especially when the disease is complicated by osteomyelitis and abscess.

PATIENT CONCERNS

Here, we report a 76-year-old woman without risk factors who visited our hospital for pain and redness, swelling on the left anterior chest wall.

DIAGNOSIS

Magnetic resonance imaging showed infectious arthritis in the left SCJ, with multiple abscess pockets at the subcutaneous layer of anterior chest wall communicating with the joint cavity. Streptococcus agalactiae was isolated from blood culture.

INTERVENTION

She was treated with 6 weeks of antibiotic therapy.

OUTCOMES

After antibiotic treatment, she was successfully treated without recurrence.

LESSONS

Besides surgery, medical treatment should also be considered for sternoclavicular joint septic arthritis, depending on patient status and the causative pathogen. Physicians should be aware of this rare disease to facilitate its prompt diagnosis and management.

Chryseobacterium arthrosphaerae ventriculitis: A case report

INTRODUCTION

Chryseobacterium arthrosphaerae is a gram-negative bacteria, known for its intrinsic multidrug resistance, which can lead to treatment difficulties.

PATIENT CONCERNS

A 56-year-old male had an indwelling external ventricular drainage catheter for 6 months and had been frequently treated with antibiotics for nosocomial infections. He showed cerebrospinal fluid pleocytosis and an abrupt fever during hospitalization.

DIAGNOSIS

He was diagnosed as a ventriculitis caused by Chryseobacterium arthrosphaerae (C arthrosphaerae).

INTERVENTION

Initially, we used ciprofloxacin as the backbone in combination with minocycline (and rifampin). However, fever and pleocytosis persisted, and improvement was slow. We then switched the minocycline and rifampin regiment to trimethoprim/sulfamethoxazole. Following this switch of antibiotics, the patient's pleocytosis rapidly improved, allowing the replacement of his external ventricular drainage catheters. C arthrospharae was no longer growing in cerebrospinal fluid and he was recovered from ventriculitis.

OUTCOMES

The patient remains alive without any incidence of C arthrosphaerae recurrence.

CONCLUSION

We propose trimethoprim/sulfamethoxazole alone or in combination with ciprofloxacin to be good candidates for the treatment of ventriculitis by C arthrosphaerae.

Convalescent Plasma Therapy in Coronavirus Disease 2019: a Case Report and Suggestions to Overcome Obstacles

Coronavirus disease 2019 (COVID-19) is rapidly spreading around the world, causing much morbidity and mortality everywhere. However, effective treatments or vaccines are still not available. Although convalescent plasma (CP) therapy can be useful in the treatment of COVID-19, it has not been widely used in Korea because of the concerns about adverse effects and the difficulty in matching patients to donors. The use of ABO-incompatible plasma is not contraindicated in treatment, but can be hesitated due to the lack of experience of physicians. Here, we describe a 68-year old man with COVID-19 who was treated ABO-incompatible plasma therapy; additionally, we comment on the acute side effects associated with ABO mismatch transfusion. To overcome the obstacles of donor-recipient connections (schedule and distance), we propose the storage of frozen plasma, modification of the current Blood Management Law, and the establishment of a CP bank. We suggest that experience gained in CP therapy will be useful for not only the treatment of COVID-19, but also for coping with new emerging infectious diseases.

Effectiveness of single-dose administration of inactivated hepatitis A virus vaccination in the Republic of Korea armed forces, 2013-2016

The Republic of Korea Armed Forces has implemented the hepatitis A virus (HAV) vaccination programme with a single-dose administration schedule in new recruits since 2013. A single-dose administration was selected for economic feasibility. We analysed the effectiveness of the single-dose HAV vaccination in a young and healthy population. To measure the effectiveness of the programme, we observed the incidence of HAV between the vaccinated and unvaccinated groups. A comparison between the two groups during the vaccine introduction period (2013-2016) revealed a lower incidence rate of infection in the vaccinated group (3 cases/603 550 person-years) than in the unvaccinated group (21 cases/1 020 450 person-years). The effectiveness of single-dose HAV vaccination was found to be 75.85%.

Systematic review and meta-analysis of immune response of double dose of hepatitis B vaccination in HIV-infected patients

INTRODUCTION

The prevalence of co-infection of hepatitis B virus (HBV) and human immunodeficiency virus (HIV) is high and increases risk of hepatitis B chronicity and mortality. Despite guidelines for HIV-infected patients to be immunized against HBV, the immunogenicity of the HBV vaccination in HIV-infected patients is lower than that in the HIV-seronegative population.

METHOD

In this study, we performed a systematic review of the literature and meta-analysis of randomized clinical trials to investigate the response rate to an increased dose of HBV vaccination in HIV-infected patients. A fixed-effects model, with heterogeneity and sensitivity analyses, was used. We identified nine studies involving 970 HIV-positive vaccine recipients.

RESULTS

The study results were divided into two groups, depending on the time when antibody against hepatitis surface antigen was measured. Results showed a significant increase in response rates among patients who received a double dose of the vaccine versus the standard dose in both subgroups; the pooled odds ratio (OR) was 1.76 (95% confidence interval [CI]: 1.36-2.29) and 2.28 (95% CI: 1.73-3.01) for the rate that was measured 4-6 weeks and >12 months after completion of vaccination, respectively. The total OR was 1.99 (95% CI: 1.64-2.41). No heterogeneity was found.

DISCUSSION

Our meta-analysis shows that a double dose of the HBV vaccine may significantly improve the immune response in HIV-infected patients. Higher immunogenicity was observed, when it was measured 4-6 weeks and >12 months after completion of the vaccination.

A case of Henoch-Schönlein purpura associated with scrub typhus

BACKGROUND

Henoch-Schönlein purpura (HSP) may be caused by several allergens. However, to date, HSP caused by Orientia tsutsugamushi has not been reported. Here, we report an unusual rash with features of HSP caused by Orientia tsutsugamushi.

CASE PRESENTATION

A man visited a tertiary hospital with bilateral symmetrical purpura and fever. He presented with an eschar in the left popliteal fossa and proteinuria. He was diagnosed with tsutsugamushi disease by indirect fluorescent antibody and positive polymerase chain reaction tests. Purpura biopsy demonstrated a feature of leukocytoclastic vasculitis and IgA deposition in dermal vessels, indicative of HSP.

CONCLUSIONS

When examining patients with unique rashes, such as in this case, we suggest investigating out-door activities and evidence of mite bites. Furthermore, differential diagnosis of tsutsugamushi disease should be considered when necessary.

Splenic Infarction in Plasmodium vivax Infection in South Korea

Splenic infarction caused by malaria can be fatal, but its incidence and clinical presentation are not well-known. Thus, we investigated the prevalence and characteristics of splenic complications in patients with vivax malaria from 2005 to 2017 in a university hospital. Among 273 patients who were diagnosed with Plasmodium vivax infection by blood smear, 92 underwent abdominal computed tomography or ultrasonography. Twelve patients had splenic infarction. All patients with splenic infarction recovered after treatment with antimalarial drugs, without surgery and intervention. Although anemia and prolonged fever may be risk factors for splenic infarction, the incidence of these events was insufficient for a detailed analysis.

Effectiveness of a single dose of the quadrivalent meningococcal conjugate vaccine, MenACWY-CRM, in the Korean Armed Forces

Conjugate vaccines are widely used to overcome the disadvantages of polysaccharide vaccines in the prevention of meningococcal disease. However, limited studies have examined the clinical effectiveness of single-dose meningococcal quadrivalent conjugate vaccines in adults. We assessed the effectiveness of the meningococcal vaccination program in the Republic of Korea Armed Forces, since 2013. Following vaccination program implementation, meningococcal disease cases decreased from 0.52/100,000 to 0.06/100,000 and the number of deaths declined from four to zero. Two meningococcal cases that developed post-implementation were identified as serotype B and X. The effectiveness of single-dose conjugate vaccination in recruits, expressed as the incidence rate ratio, was 0.88 during a 19-23-month observation period. These results indicate that meningococcal infections can be prevented by single-dose administration of the quadrivalent conjugate vaccine in at-risk groups, such as soldiers, travelers, and students in dormitories. Continuous investigation is needed to determine serogroup change, including B serogroups.

Geographic distribution of Tick-borne encephalitis virus complex

A comprehensive understanding of the geographic distribution of the tick-borne encephalitis virus (TBEV) complex is necessary due to increasing transboundary movement and cross-reactivity of serological tests. This review was conducted to identify the geographic distribution of the TBEV complex, including TBE virus, Alkhurma haemorrhagic fever virus, Kyasanur forest disease virus, louping-ill virus, Omsk haemorrhagic fever virus, and Powassan virus. Published reports were identified using PubMed, EMBASE, and the Cochrane library. In addition to TBEV complex case-related studies, seroprevalence studies were also retrieved to assess the risk of TBEV complex infection. Among 1406 search results, 314 articles met the inclusion criteria. The following countries, which are known to TBEV epidemic region, had conducted national surveillance studies: Austria, China, Czech, Denmark, Estonia, Finland, Germany, Hungary, Italy, Latvia, Norway, Poland, Romania, Russia, Switzerland, Sweden, Slovenia, and Slovakia. There were also studies/reports on human TBEV infection from Belarus, Bulgaria, Croatia, France, Japan, Kyrgyzstan, Netherland, and Turkey. Seroprevalence studies were found in some areas far from the TBEV belt, specifically Malaysia, Comoros, Djibouti, and Kenya. Kyasanur forest disease virus was reported in southwestern India and Yunnan of China, the Powassan virus in the United States, Canada, and east Siberia, Alkhurma haemorrhagic fever virus in Saudi Arabia and east Egypt, and Louping-ill virus in the United Kingdom, Ireland, and east Siberia. In some areas, the distribution of the TBEV complex overlaps with that of other viruses, and caution is recommended during serologic diagnosis. The geographic distribution of the TBEV complex appears to be wide and overlap of the TBE virus complex with other viruses was observed in some areas. Knowledge of the geographical distribution of the TBEV complex could help avoid cross-reactivity during the serologic diagnosis of these viruses. Surveillance studies can implement effective control measures according to the distribution pattern of these viruses.

The Eschar Size and Early Inoculation Lesion of Tsutsugamushi Disease on Jeju Island, Korea

Background

Tsutsugamushi disease, or scrub typhus, is an acute febrile illness caused by Orientia tsutsugamushi, which is followed by chronic latent infection. People who reside in areas endemic of tsutsugamushi disease may be frequently reinfected with this organism. Volunteers who are experimentally reinfected with O. tsutsugamushi manifest various systemic and local reactions, including the presence of small-sized eschar. The present study recorded the morphology and size of eschars in patients with tsutsugamushi disease on Jeju Island, Korea.

Materials and Methods

From March 2018 to February 2019, 23 patients manifesting clinical characteristics and epidemiologic features of tsutsugamushi disease on Jeju Island were investigated. For comparison of eschar sizes between the two regions, 12 patients with tsutsugamushi disease in Incheon were similarly examined.

Results

Three patients, two on the first day and one on the fourth day of fever, presented with papules of 2 – 5 mm in diameter. Another three patients, one on the second day and two on the fourth day, presented with ruptured vesicles of 5 – 8 mm in diameter. Thirteen patients presented with eschars covered with dark scabs, with a median diameter of 5 (95% confidence interval [CI], 5 – 7.5) × 4 (95% CI, 3 – 5) mm. The medians of the eschar sizes did not differ between the two cities (P = 0.46 by Mann-Whitney U test), but eschars ≥10 mm in diameter were more frequent in Incheon than in Seogwipo-si (4 of 12 vs. 0 of 13 patients, P = 0.04 by Fisher's exact test). One patient presented with multiple eschars, and no eschar was detected in the remaining three patients. Among 11 Jeju Island patients with positive IgG and IgM antibodies, seven patients revealed higher IgG than IgM antibody titers during the acute phase of the illness, i.e., the IgG antibody response, two patients had equal IgG and IgM titers, and two patients presented the IgM antibody response. Life-threatening complications and death were not observed in this study.

Conclusion

The patients in Seogwipo-si had small-sized eschars and occasionally exhibited non-necrotic lesions. Many patients had serologically reinfected tsutsugamushi disease. Further studies are needed to investigate the association between these findings.

Antinuclear antibodies in infectious diseases

Introduction: Antinuclear antibody (ANA) tests are widely used for the diagnosis of autoimmune diseases, but ANAs are also commonly found in patients with various infections. This retrospective study aimed to investigate the relationship between infections and ANA status.Methods: Patients that visited the Department of Infectious Diseases at Inha University Hospital between January 2007 and July 2018 were investigated. We analysed their ANA test results and reviewed rheumatic and infectious diagnoses of patients with positive ANA findings.Results: Of the 9,320 patients during the study period, 1,111 underwent ANA testing and 110 tested positive. Seven of the 110 patients were previously diagnosed with ANA-positive disease, and 21 were diagnosed with autoimmune disease during the present study. Of the remaining 82 patients, 43 were confirmed with infectious disease. The most common pathogen was Mycobacterium tuberculosis (n = 10), followed by Treponema pallidum (n = 5), Orientia tsutsugamushi (n = 5), Escherichia coli (n = 5), Bartonella henselae (n = 3), and human immunodeficiency virus (n = 3). Of the 39 patients without a confirmed pathogen, 7 were seropositive for O. tsutsugamushi, B. henselae, or Rickettsia spp. Patients were observed at an average of 24 weeks in our hospital. One patient developed systemic lupus erythematosus after being diagnosed with Epstein-Barr virus-induced infectious mononucleosis, and another patient developed adult-onset Still's disease after being diagnosed with scrub typhus.Conclusion: This study showed that various relationships exist between infections and rheumatic diseases. In particular, several patients with a positive ANA test result were found to have intracellular infections such as mycobacterial infections, syphilis, or scrub typhus.

Two cases of immune reconstitution inflammatory syndrome in HIV patients treated with thalidomide

Immune reconstitution inflammatory syndrome (IRIS) is a clinical manifestation that accompanies paradoxical deterioration of symptoms in human immunodeficiency virus (HIV)-infected patients after commencement of antiretroviral treatment. This disease is caused by immune dysregulation, resulting in a cytokine storm and limited effector T-cell function. IRIS treatment involves supportive care and corticosteroid therapy to regulate the immune response. However, prolonged steroid therapy may increase the risk of opportunistic infections. Previous studies have highlighted the use of thalidomide to shorten the duration of steroid use. Herein, we report two cases of IRIS in HIV-infected patients whose symptoms were successfully controlled with thalidomide therapy. Both patients had opportunistic infections involving the central nervous system; one patient had cryptococcal meningitis and the other had progressive multifocal leukoencephalopathy.

Subcapsular Splenic Hemorrhage in Vivax Malaria

In malaria, splenic rupture is a serious complication potentially leading to death. Subcapsular hemorrhage of spleen is thought to be an impending sign of splenic rupture; however, the characteristics of subcapsular hemorrhage are not well known. We report 3 cases of subcapsular hemorrhage of the spleen in vivax malaria, with varying degrees of severity. Case 1 showed subcapsular hemorrhage without splenic rupture, was treated by antimalarial drug without any procedure. The healing process of the patient's spleen was monitored through 6 computed tomography follow-up examinations, over 118 days. Case 2 presented subcapsular hemorrhage with splenic rupture, treated only with an antimalarial drug. Case 3 showed subcapsular hemorrhage with splenic rupture and hypotension, treated using splenic artery embolization. They all recovered from subcapsular hemorrhage without any other complications. These 3 cases reveal the process of subcapsular hemorrhage leading to rupture and a potentially fatal outcome. The treatment plan of subcapsular hemorrhage should be determined carefully considering the vital signs, changes in hemoglobin, and bleeding tendency.

Determinants of Compliance of Travelers with Vaccination and Malaria Prophylaxis at a Travel Clinic

BACKGROUND

Pre-travel medical consultation is essential to reduce health impairment during travel. Yellow fever vaccination (YFV) is mandatory to enter some endemic countries. In this study, we evaluated the factors that affect compliance with appropriate prevention of infectious diseases in travelers who visited clinic for YFV.

METHODS

For this retrospective study, chart reviews for 658 patients who visited a travel clinic for YFV before travel were conducted. The period of this study was from January 2016 to September 2018. The associations between appropriate vaccination and factors such as travel duration, destination, time of visiting clinic before departure, and purpose of travel were analyzed.

RESULTS

Among 658 patients who got YFV during the study period, 344 patients (52.3%) received additional vaccination or malaria prophylaxis following a physician's recommendation. Travelers who visited the clinic more than 21 days before departure were more compliant than those who visited 14 days or fewer before departure (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.23-2.93; P = 0.004). Travelers visiting Africa were more compliant than were those traveling to South and Central America (OR, 1.97; 95% CI, 1.34-2.90; P = 0.001). Travelers in age groups of 40-49 years and over 70 years were less compliant than the 18-29 years old population (OR, 0.51; 95% CI, 0.28-0.93; P = 0.027 and OR, 0.19; 95% CI, 0.04-0.84; P = 0.03, respectively). Also, those who traveled for tour or to visit friends or relatives were more compliant than those who departed for business (OR, 0.77; 95% CI, 1.03-3.56; P = 0.04).

CONCLUSION

For appropriate vaccination, pre-travel consultation at least 3 weeks before departure is crucial. Travelers should be aware of required vaccination and malaria prophylaxis before visiting South and Central America and Asia. Plans to enhance compliance of the elderly and business travelers should be contrived.

Two Imported Cases of Babesiosis with Complication or Co-Infection with Lyme Disease in Republic of Korea

Babesiosis, caused by Babesia microti and B. divergens, is transmitted by Ixodid ticks. Symptoms of babesiosis vary from a mild flu-like illness to acute, severe, and sometimes fatal and fulminant disease. In Korea, 7 imported babesiosis cases and 1 endemic case have been reported. We report 2 cases of severe babesiosis initially mistaken as malaria. The first patient was complicated by shock and splenic infarction, the other co-infected with Lyme disease. As the population traveling abroad increases every year, physicians should be aware of babesiosis which mimics malaria, co-infection with other diseases, and its complications.

Current Status of Tick-Borne Diseases in South Korea

BACKGROUND

Bites with tick-borne pathogens can cause various bacterial, viral, or parasitic diseases in humans. Tick-transmitted diseases are known as contributing factors to the increasing incidence and burden of diseases. The present article investigated the epidemiology of tick-borne diseases in South Korea.

METHODS

The incidence and distribution of common tick-borne diseases in Korea (Lyme disease, Q fever, and severe fever with thrombocytopenia syndrome [SFTS]) were investigated and analyzed, using data from the Korea Centers for Disease Control and Prevention (KCDC) infectious disease reporting system. A literature review was compiled on the current status of uncommon tick-borne diseases (Rickettsia, anaplasmosis, ehrlichiosis, bartonellosis, tularemia, tick-borne encephalitis, and babesiosis).

RESULTS AND CONCLUSIONS

In South Korea, SFTS is an emerging disease, showing a rapid increase in reports since 2012, with high mortality. Likewise, reports of Lyme disease and Q fever cases have also been rapidly increasing during 2012-2017, although caution should be taken when interpreting these results, considering the likely influence of increased physician awareness and reporting of these diseases. Other tick-borne diseases reported in South Korea included spotted fever group rickettsiae, anaplasmosis, ehrlichiosis, tularemia, Bartonella, and babesiosis. Evidences on human infection with tick-borne encephalitis virus and Crimean-Congo hemorrhagic fever were recently unavailable, but both need constant monitoring.

Malaria control and chemoprophylaxis policy in the Republic of Korea Armed Forces for the previous 20 years (1997-2016)

Background

Vivax malaria reemerged along the Demilitarized Zone (DMZ), Republic of Korea (ROK), in 1993. While it was hypothesized that vivax malaria would spread throughout the peninsula, nearly all cases were due to exposure near the DMZ. To reduce spillover of vivax malaria to the civilian community, the ROK Ministry of National Defense (MND) initiated malaria prevention policies including a large-scale chemoprophylaxis programme in malaria high-risk areas in 1997. The present study investigated the overall changes in the incidence of malaria among ROK soldiers and the mass chemoprophylaxis program from 1997 to 2016.

Results

Peak numbers of vivax malaria were reported in 2000, with most cases reported near the DMZ, before declining to the current levels. To combat the rapid increase in the number of malaria cases and its expansion throughout the ROK, the MND implemented mosquito control and personal protection programmes. The MND also implemented a large-scale vivax malaria chemoprophylaxis programme using hydroxychloroquine (400 mg weekly) in 1997, and primaquine (15 mg × 14 days) as terminal chemoprophylaxis in 2001. Additionally, an improved medical system enabled the rapid detection and treatment of malaria to reduce morbidity and decrease transmission of malaria from humans to mosquitoes. Following the full implementation of these programmes, the incidence of vivax malaria declined in both ROK Armed Forces and civilian populations. Subsequently, several changes in the ROK Armed Forces chemoprophylaxis programme were implemented, including the reduction of the period of hydroxychloroquine prophylaxis by 2 months (2008) and other changes in the chemoprophylaxis policy, e.g., only ROK Armed Forces personnel in moderate risk groups received terminal primaquine chemoprophylaxis (2011), and in 2016, the discontinuation of terminal primaquine chemoprophylaxis in moderate-risk area.

Conclusions

The resurgence of vivax malaria in the ROK Armed Forces personnel near the DMZ was successfully suppressed through the implementation of a mass malaria chemoprophylaxis programme initiated by the MND in 1997, as well as several other factors that may have contributed to the reduction of malaria transmission since 2000. Given the current malaria situation in the ROK and North Korea, it is necessary to reevaluate the ROK Armed Forces and civilian malaria control policies.

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2449-4) contains supplementary material, which is available to authorized users.

Serologic Study of Bartonella henselae in Patients with Acute Undifferentiated Febrile Illness in Korea

BACKGROUND

Bartonella infection is an emerging cause of acute febrile illness; however, its significance has not been thoroughly investigated. We studied the antibody specific to Bartonella henselae in patients with various febrile diseases in Korea.

MATERIALS AND METHODS

A total of 177 patients with acute febrile illness who were managed at the Inha University Hospital from February 2012 to January 2013 were evaluated with an in-house immunofluorescent antibody test to detect B. henselae immunoglobulin G (IgG) antibody. The clinical features of the patients included fever of undetermined origin (n = 88 patients), lymphadenopathy (n = 28), febrile rash (n = 17), respiratory infection (n = 12), aseptic meningitis (n = 7), intra-abdominal infection (n = 5), arthritis (n = 4), and other conditions (n = 16). We reviewed the medical records of these patients and collected demographic data, clinical features, and their histories of animal exposure.

RESULTS

Among the 177 patients with acute febrile illness, 23.7% (42/177) had elevated levels of IgG antibodies to B. henselae (≥1:160). Of these seropositive patients, 32.4% (12/37) had contact with animals and had developed arthralgia (29.5%), headache (25%), or lymphadenopathy (15.9%). Seven (16.7%) of the 42 patients had higher IgG titers (≥1:640). Among them, four patients presented fourfold increase/decrease of IgG in convalescent serum. According to the clinical diagnosis, the antibody positivity rates were as follows: 24/88 with undifferentiated fever, 8/28 with lymphadenopathy, 4/17 with febrile rash, 2/12 with respiratory infection, 2/7 with aseptic meningitis, and 2/16 with other illnesses.

CONCLUSIONS

There was high prevalence of B. henselae in patients with undifferentiated fever in Korea, for which further research is needed.

The seroprevalence of Bartonella henselae in healthy adults in Korea

BACKGROUND/AIMS

Cat-scratch disease (CSD), caused by Bartonella henselae is one of the most common zoonosis. However, only several cases of B. henselae infection have been reported in Korea. This study investigated the seroprevalence of B. henselae in healthy adults and related risk factors.

METHODS

Serum samples from 300 healthy participants were analyzed using an immunoglobulin G immunof luorescence assay (IFA) for B. henselae isolated in Korea. Surveys on the risk factors for B. henselae infection were conducted simultaneously.

RESULTS

Of the participants, 47.7% and 15.0% raised dogs and cats, respectively. The overall seroprevalence of B. henselae was 15.0% (IFA titer ≥ 1:64). Participants who had raised cats showed 22.2% seropositivity against B. henselae, and those with no experience with cats showed 13.7% seroprevalence (p = 0.17). Participants who had cats as pets or been scratched by cats, showed 9.8% seropositivity against B. henselae (IFA titer ≥ 1:256). However, those who had not raised or been scratched by a cat showed 2.0% seropositivity (p = 0.015).

CONCLUSIONS

In Korea, the seroprevalence of B. henselae is higher than expected, suggesting that Bartonella infection due to B. henselae is not uncommon. Cats are proposed to play a more important role than dogs in transmission of CSD.

Severe Plasmodium vivax infection in Korea

Background

Although severe malaria by Plasmodium vivax has been increasingly reported, there are marked variations in the type and rate of the complications by geographic area. This is possibly because of the presence of concurrent falciparum malaria or bacteraemia, and of differences in underlying immune status among the infected subjects. Furthermore, published studies on P. vivax in temperate regions are limited. The present study investigated severe vivax malaria in Korea, where only vivax malaria occurs. Hence, other compounding factors are rare. Additionally, most of the patients are possibly non-immune to this malarial disease.

Methods

Adults with vivax malaria observed in one 860-bed university hospital from January 2006 to December 2012 were retrospectively evaluated. Seventeen patients who had travelled overseas within 6 months before the presentation of malaria were excluded. Severe vivax malaria was diagnosed according to World Health Organization criteria. Other complications were also investigated.

Results

Two-hundred and ten patients were enrolled, of which 88 (41.9%) were treated as inpatients and the remainder as outpatients. Eleven patients were treated in an intensive care unit; among them, five patients received mechanical ventilation, and one needed extracorporeal membrane oxygenation therapy (ECMO) additionally. Severe vivax malaria was identified in 44 patients (21.0%), and the most common severe complication was pulmonary manifestation (40/188, 21.9%), which was followed by cerebral malaria (5/210, 2.4%), shock (4/210, 1.9%), spontaneous bleeding (3/210, 1.4%), metabolic acidosis (3/210, 3.5%) and acute kidney injury (2/210, 1.0%). Unusual complications, such as splenic infarction (ten patients) and retinal haemorrhage (two patients) were sometimes observed. There were no deaths, but the case involving ECMO was potentially fatal.

Conclusions

Plasmodium vivax infection can be severe to be fatal and is frequently associated with various complications in non-immune adults. The frequency of each complication seems to differ from other countries. Hence, further investigation is needed to elucidate the causes and mechanisms responsible for these differences.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-017-1684-4) contains supplementary material, which is available to authorized users.

A Case of Scrub Typhus Complicated by Adult Respiratory Distress Syndrome and Successful Management with Extracorporeal Membrane Oxygenation

A 67-year-old woman was diagnosed as having scrub typhus with pneumonitis. On admission, she was started on a combination therapy with levofloxacin and doxycycline. However, the patient developed severe acute respiratory distress syndrome (ARDS) on the 2nd day, and as a result, she underwent extracorporeal membrane oxygenation (ECMO). She was weaned from ECMO on the 10th day, as her respiratory status gradually improved. She was discharged without sequelae on the 23rd day. The outcome suggests that the use of ECMO should be considered for patients with ARDS induced from scrub typhus.

In Vitro Activity of Tigecycline Against Orientia tsutsugamushi

Scrub typhus is a zoonosis caused by Orientia tsutsugamushi (O. tsutsugamushi) occurring mainly in autumn in Korea. The need of new antibiotics has arisen with a report on strains resistant to antibiotics and chronic infection. This study aims to identify susceptibility of tigecycline in-vitro as a new therapeutic option for O. tsutsugamushi. Antibacterial activity of tigecycline against the O. tsutsugamushi was compared with doxycycline using flow cytometry assay. The inhibitory concentration 50 (IC₅₀) was 3.59×10⁻³ μg/mL in doxycycline-treated group. Whereas in 0.71×10⁻³ μg/mL tigecycline-treated group. These findings indicate that tigecycline may be a therapeutic option for the treatment of scrub typhus.

A follow-up study on extracorporeal fixation of condylar fractures using vertical ramus osteotomy

Objectives

The aim of this study is to report the results of extracorporeal fixation in patients with mandibular condylar fractures and compare them with the clinical results of conservative treatment.

Materials and Methods

The medical records of 92 patients (73 male [M] : 19 female [F], age 13-69 years, mean 33.1 years) treated for condylar fractures at the Department of Oral and Maxillofacial Surgery in Sun Dental Hospital (Daejeon, Korea) from 2007 to 2012 were reviewed. Patients were divided into three groups: group A (23 patients; M : F=18 : 5, age 21-69 years, mean 32.6 years), treated with extracorporeal fixation; group B (30 patients; M : F=24 : 6, age 16-57 years, mean 21.1 years), treated by conventional open reduction; and group C (39 patients; M : F=31 : 8, age 16-63 years, mean 34.4 years), treated with the conservative method ('closed' reduction). Clinical and radiographic findings were evaluated and analyzed statistically.

Results

Occurrence of postoperative condylar resorption correlated with certain locations and types of fracture. In this study, patients in group A (treated with extracorporeal fixation) did not demonstrate significant postoperative complications such as malocclusion, mandibular hypomobility, temporomandibular disorder, or complete resorption of condyle fragments.

Conclusion

In superiorly located mandibular condyle fractures, exact reconstruction of condylar structure with the conventional open reduction technique can be difficult due to the limited surgical and visual fields. In such cases, extracorporeal fixation of the condyle using vertical ramus osteotomy may be a better choice of treatment because it results in anatomically accurate reconstruction and low risk of complications.

Therapeutic drug concentrations of teicoplanin in clinical settings

Background

Teicoplanin is a glycopeptide antibiotic that is widely used in clinical practice for the treatment of infections caused by drug-resistant Gram-positive bacteria. The aim of this study was to analyze plasma teicoplanin concentrations to determine the percentage of patients in whom therapeutic concentrations of teicoplanin were achieved in clinical practice.

Materials and Methods

The plasma teicoplanin concentrations of hospitalized patients receiving treatment at a teaching hospital were retrospectively analyzed. The target level was defined as a plasma teicoplanin concentration of 10 mg/L or greater, since this was generally regarded as the lower limit of the optimal concentration range required for the effective treatment of a majority of infections.

Results

Patients with sub-optimal (< 10 mg/L) plasma teicoplanin concentrations constituted nearly half of the total study population. The majority of these patients received the recommended loading dose, which were three 400 mg doses administered every 12 hours. Sub-group analysis showed a trend that the group receiving loading dose was more likely to reach the optimal teicoplanin concentration.

Conclusions

The data revealed that a significant proportion of patients in clinical practice achieved only sub-optimal teicoplanin concentrations, which emphasizes the importance of the mandatory use of loading dose and routine therapeutic drug monitoring. Treatment reassessment and simulation of individual dose regimens may also be necessary to achieve optimal drug concentrations.

Better understanding of the filtration characteristics in the flexible fibre filter module (3FM)

This study is about the particle retention and filtration characteristics of fibre filter. Four laboratory scale fibre filters with different heights were used in parallel at various packing densities and filtration velocities. Of all of the operating parameters studied, filtration velocity had the most influence. Contrary to general theories, pressure drop increases slightly during the filtration in spite of the continuous retention of particles. This may have occurred because of large porosity of the packing (about 93%). This might be considered an advantage of the filter and something that makes it economic. The higher the filtration velocity, the larger the mass of particles retained in the filter. For filtration velocities of 20 and 40 m/h, particles smaller than 5 microm are retained as proven by the particle size distribution at the inlet and outlet.

Enhancing flexible fiber filter (3FM) performance using in-line coagulation

A new packing for deep bed filtration using Flexible Fibers has been proposed and developed on a very large scale for tertiary treatment of wastewater. The purpose of this study is to check the possibility of using this technology for the production of drinking water from surface water. In this study, the feasibility of the fiber filter application on water treatment was examined and the removal efficiency of fiber filter was improved using an in-line coagulant injection method. The experiments were carried out at pilot scale. The filter was packed with bundles of polyamide fibers with a bed porosity of 93%. Nak-dong River was used as the filter influent water and alum, PSOM, and PAC were used as the coagulants. The coagulants were injected by the in-line injection method. Small dosages (1-5 mg/L) of the polymeric coagulants (PSOM and PAC) showed an increase of removal efficiency compared to the operation without coagulants. Specifically, 1 mg/L of PAC showed the longest filtration time. Considering filtration time, filtrate quality, and filtered volume, the filtration velocity of 120 m/hr was chosen as an optimum value. For long-term operations, the effluent quality was 0.4 NTU and the removal efficiency was stable for the given optimum conditions.

Forecasting influent flow rate and composition with occasional data for supervisory management system by time series model

The information on the incoming load to wastewater treatment plants is not often available to apply modelling for evaluating the effect of control actions on a full-scale plant. In this paper, a time series model was developed to forecast flow rate, COD, NH4(+)-N and PO4(3-)-P in influent by using 250 days data of field plant operation data. The data for 150 days and 100 days were used for model development and model validation, respectively. The missing data were interpolated by the spline method and the time series model. Three different methods were proposed for model development: one model and one-step to seven-step ahead forecasting (Method 1); seven models and one-step-ahead forecasting (Method 2); and one model and one-step-ahead forecasting (Method 3). Method 3 featured only one-step-ahead forecasting that could avoid the accumulated error and give simple estimation of coefficients. Therefore, Method 3 was the reliable approach to developing the time series model for the purpose of this research.

Full-cyclic control strategy of SBR for nitrogen removal in strong wastewater using common sensors

A full-cyclic automatic control strategy for sequencing batch reactors (SBR) was proposed using only common sensors such as ORP, DO and pH. The main objective was to develop a generally applicable and robust control strategy. To accomplish this, various control schemes found in the literature or suggested by authors were examined at diverse ammonia loads and SCOD/NH4(+)-N ratios. Advantages and constraints of each scheme were discussed and compared. Ammonia load was estimated with DO lag time during the aerobic stage, and then the influent pump was manipulated to meet the desired load at the next anoxic stage. A partial denitrification scheme was chosen for the anoxic stage period control, to save anoxic time and external carbon. For external carbon dosage control, intermittent feeding at each anoxic stage was concluded to be a suitable scheme. The anoxic stage period could be successfully controlled by the combination of pH increase and DO increase. Every suggested control scheme was incorporated into a full-cyclic control strategy and tested at 0.02, 0.035, 0.08 kg NH4(+)-N/m3/sub-cycle. From the results, it is expected to perform unmanned automatic SBR operation with this strategy.

Treatment of strong nitrogen swine wastewater in a full-scale sequencing batch reactor

Treatment of swine wastewater containing strong nitrogen was attempted in a full-scale SBR. The strongest swine wastewater was discharged from a slurry-type barn and called swine-slurry wastewater (SSW). Slightly weaker wastewater was produced from a scraper-type barn and called swine-urine wastewater (SUW). TCOD, NH4+-N and TSS in raw SSW were 23,000-72,000 mg/L, 3,500-6,000 mg/L and 17,000-50,000 mg/L, respectively. A whole cycle of SBR consists of 4 sub-cycles with anoxic period of 1 hr and aerobic period of 3 hr. The maximum loading rates of both digested-SSW and SUW were similar to 0.22 kg NH4+-N/m3/day whereas the maximum loading rates of raw SSW was up to 0.35 TN/m3/day on keeping the effluent quality of 60 TN mg/l. The VFAs portion of SCOD in raw SSW was about more than 60%. The VFAs in SUW and digested-SSW were about 22% and 15%, respectively. NH4+-N and PO4(3-)-P in SSW were removed efficiently compared to those in digested-SSW and DUW because SSW had high a C/N ratio and readily biodegradable organic. High concentration of organic was useful to enhance denitrification and P uptake. Also the amount of external carbon for denitrification was reduced to 5% and 10% of those for digested-SSW and SUW.

External carbon feeding strategy for enhancing nitrogen removal in SBR

Effective method for feeding an external carbon source (ECS) in SBR was investigated to enhance denitrification based on modifying the anoxic/aerobic sub-cycle for swine wastewater treatment. The wastewater discharged from the scraper-type barns contains relatively low readily biodegradable organic. Therefore NOx-N was accumulated during repeating sub-cycle in SBR operation. When acetic acid was fed as ECS during the final sub-cycle, the maximum nitrogen removal rate was 0.22 kg N/m3/d. This was due to both less denitrification rate during the sub-cycle period and inhibition of denitrification by pH drop during the final cycle. The pH drop was caused by a large amount of ECS feeding to remove high concentration of NOx-N in the final period. To overcome these limitations and achieve higher nitrogen removal rate, the intermittent ECS feeding method with raw wastewater at every anoxic period was developed. Using the modifying ECS feeding method, the removal rate was increased to 0.45 kg N/m3/d without NOx-N accumulation.