Myoung Don Oh

Community-Acquired versus Nosocomial Klebsiella pneumoniae Bacteremia: Clinical Features, Treatment Outcomes, and Clinical Implication of Antimicrobial Resistance

We conducted this study to compare clinical features, outcomes, and clinical implication of antimicrobial resistance in Klebsiella pneumoniae bacteremia acquired as community vs. nosocomial infection. A total of 377 patients with K. pneumoniae bacteremia (191 community-acquired and 186 nosocomial) were retrospectively analyzed. Neoplastic diseases (hematologic malignancy and solid tumor, 56%) were the most commonly associated conditions in patients with nosocomial bacteremia, whereas chronic liver disease (35%) and diabetes mellitus (20%) were the most commonly associated conditions in patients with community-acquired bacteremia. Bacteremic liver abscess occurred almost exclusively in patients with community-acquired infection. The overall 30-day mortality was 24% (91/377), and the mortality of nosocomial bacteremia was significantly higher than that of community-acquired bacteremia (32% vs. 16%, p<0.001). Of all community-acquired and nosocomial isolates, 4% and 33%, respectively, were extended-spectrum cephalosporin (ESC)-resistant, and 4% and 21%, respectively, were ciprofloxacin (CIP)-resistant. In nosocomial infections, prior uses of ESC and CIP were found to be independent risk factors for ESC and CIP resistance, respectively. Significant differences were identified between community-acquired and nosocomial K. pneumoniae bacteremia, and the mortality of nosocomial infections was more than twice than that of community-acquired infections. Antimicrobial resistance was a widespread nosocomial problem and also identified in community-acquired infections.

Middle East Respiratory Syndrome Coronavirus Superspreading Event Involving 81 Persons, Korea 2015.

Since the first imported case of Middle East respiratory syndrome coronavirus (MERS-CoV) infection was reported on May 20, 2015 in Korea, there have been 186 laboratory-confirmed cases of MERS-CoV infection with 36 fatalities. Ninety-seven percent (181/186) of the cases had exposure to the health care facilities. We are reporting a superspreading event that transmitted MERS-CoV to 81 persons at a hospital emergency room (ER) during the Korean outbreak in 2015. The index case was a 35-yr-old man who had vigorous coughing while staying at the ER for 58 hr. As in severe acute respiratory syndrome outbreaks, superspreading events can cause a large outbreak of MERS in healthcare facilities with severe consequences. All healthcare facilities should establish and implement infection prevention and control measure as well as triage policies and procedures for early detection and isolation of suspected MERS-CoV cases.

Incidence and Seroprevalence of Hepatitis A Virus Infections among Young Korean Soldiers

This study was performed to determine the incidence and seroprevalence of hepatitis A virus (HAV) infections in young soldiers in the Republic of Korea Army. From January 2000 through December 2004, a total of 147 hepatitis A cases were reported to the Armed Forces Medical Command. The annual incidence rates were 7.4 per 100,000 persons in 2000, 1.6 in 2001, 4.4 in 2002, 9.8 in 2003, and 6.2 in 2004, based on the reported cases among approximately 500,000 soldiers. All patients were males with a median age of 21 yr (range, 19-27). The most common symptom was nausea (86.5%), and all patients had recovered without complications. In addition, in order to evaluate the seroprevalence of HAV infection in young adults, serum samples were obtained from randomly selected young subjects among those who had been admitted to the Armed Forces Capital Hospital from September 2005 to February 2006. A total of 200 subjects were enrolled in the study to analyze the anti-HAV immune status. The overall anti-HAV IgG seropositive rate was 2% (4/200, 95% CI, 0.60-5.21%). Given the changing epidemiology of the disease and the associated increase in morbidity, it was suggested that the routine HAV vaccination for Korean military personnel might be necessary.

First Imported Case of Zika Virus Infection into Korea

Since Zika virus has been spreading rapidly in the Americas from 2015, the outbreak of Zika virus infection becomes a global health emergency because it can cause neurological complications and adverse fetal outcome including microcephaly. Here, we report clinical manifestations and virus isolation findings from a case of Zika virus infection imported from Brazil. The patient, 43-year-old Korean man, developed fever, myalgia, eyeball pain, and maculopapular rash, but not neurological manifestations. Zika virus was isolated from his semen, and reverse-transcriptase PCR was positive for the virus in the blood, urine, and saliva on the 7th day of the illness but was negative on the 21st day. He recovered spontaneously without any neurological complications. He is the first case of Zika virus infection in Korea imported from Brazil.

Comparison of serological assays in human Middle East respiratory syndrome (MERS)-coronavirus infection.

Plaque reduction neutralisation tests (PRNT), microneutralisation (MN), Middle East respiratory syndrome (MERS)-spike pseudoparticle neutralisation (ppNT) and MERS S1-enzyme-linked immunosorbent assay (ELISA) antibody titres were compared using 95 sera from 17 patients with MERS, collected two to 46 days after symptom onset. Neutralisation tests correlated well with each other and moderately well with S1 ELISA. Moreover to compare antigenic similarity of genetically diverse MERS-CoV clades, the response of four sera from two patients sampled at two time periods during the course of illness were tested by 90% PRNT. Genetically diverse MERS-CoV clades were antigenically homogenous.

Outbreak of vancomycin resistant Enterococcus in a hematology/oncology unit in a Korean University Hospital, and risk factors related to patients, staff, hospital care and facilities

A vancomycin-resistant Enterococcus (VRE) outbreak occurred at a hematology/oncology (HO) service in a tertiary acute care hospital, 1 January to 30 April 2002. This study was undertaken to identify risk factors, and to establish relations between seasonal factors and this VRE outbreak. Every patient (n=82) and health care worker (HCW) (n=31) at the HO unit was screened by rectal swab and stool culture during the VRE outbreak. Environmental surface culture (n=35) and pulsed-field gel electrophoresis (PFGE) of VRE isolates were preformed. Among a total of 82 patients, 17 had VRE. All VRE isolates were E. faecium, the 6 studied further were Van A with identical PFGE patterns. Cultures of surfaces and HCWs were negative for VRE. Prolonged hospital stay (p=0.02), male gender (p=0.02), and care in a 6-bed room (p<0.01) were risk factors for acquisition of VRE. An association with the VRE outbreak period was found again for long hospital stay, but also for the antibiotic usage pattern, frequent surgery and a high proportion of new inexperienced staff (52% vs 4% before the outbreak (p<0.01, Fishers exact test). Sudden personnel turnover in high-risk units should be avoided.

Clinical and Epidemiologic Characteristics of Spreaders of Middle East Respiratory Syndrome Coronavirus during the 2015 Outbreak in Korea

Nosocomial transmission is an important characteristic of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection. Risk factors for transmission of MERS-CoV in healthcare settings are not well defined. During the Korean outbreak in 2015, 186 patients had laboratory-confirmed MERS-CoV infection. Those suspected as a source of viral transmission were categorized into the spreader groups (super-spreader [n = 5] and usual-spreader [n = 10]) and compared to the non-spreader group (n = 171). Body temperature of ≥ 38.5°C (adjusted odds ratio [aOR], 5.54; 95% confidence interval [CI], 1.38–22.30; P = 0.016), pulmonary infiltration of ≥ 3 lung zones (aOR, 7.33; 95% CI, 1.93–27.79; P = 0.003), and a more nonisolated in-hospital days (aOR, 1.32 per 1 day; 95% CI, 1.09–1.60; P = 0.004) were significant risk factors in the spreader group. There was no different clinical factor between super-spreaders and usual-spreaders. Nonisolated in-hospital days was the only factor which tended to be higher in super-spreaders than usual-spreaders (Mean, 6.6 vs. 2.9 days; P = 0.061). Early active quarantine might help reducing the size of an outbreak.

Genotypic resistance of antiretroviral drugs among drug-naive HIV type 1 patients with the background of long-term access-easy zidovudine therapy.

The prevalence of transmitted resistance to antiretroviral drugs varies geographically, with little known about this effect in Asia. In Korea, zidovudine has been widely administered, without charge, through the National AIDS program since the early 1990s; with other potent antiretroviral agents also being introduced in the late 1990s. An analysis of the drug susceptibility to antiretroviral drugs was performed by genotyping of the drug-resistant mutations in HIV on plasma samples from 50 HIV-infected patients who had received no treatment, between February 1998 and November 2002, which was interpreted according to the consensus guidelines of the International AIDS Society-USA panel. The median CD4 cell count was 100 cells/mm3; the mean plasma RNA level was (5.19 +/- 0.56) log copies per milliliter. Of the 50 subjects tested 4 (8.0%) had one or more major drug-resistance mutation. The prevalence of resistance to multiple classes of drugs was 2.0%. No mutations, associated with resistance to non nucleoside reverse transcriptase inhibitors, were identified. Resistant mutations of the reverse-transcriptase gene were found at codons 67, 70, 118, 215, and 219, and a resistant mutation of the protease gene was found only at codon 46 (2.6%, 1 of 39). There was an 8.0% prevalence of primary drug resistance to antiretroviral drugs in Korean patients infected with HIV-1.

Incidence of Atazanavir-associated Hyperbilirubinemia in Korean HIV Patients: 30 Months Follow-up Results in a Population with Low UDP-glucuronosyltransferase1A1*28 Allele Frequency

Hyperbilirubinemia is frequently observed in Caucasian HIV patients treated with atazanavir. UDP-glucuronosyltransferase 1A1 polymorphism, UGT1A1*28, which is associated with atazanavir-induced hyperbilirubinemia, is less common in Asians than in Caucasians. However, little is known about the incidence of atazanavir-associated hyperbilirubinemia in Asian populations. Our objective was to investigate the incidence of and tolerability of atazanavir-associated hyperbilirubinemia in Korean HIV patients. The prevalence and cumulative incidence of atazanavir-associated hyperbilirubinemia and UGT1A1*28 allele frequency was investigated in 190 Korean HIV-infected patients treated with atazanavir 400 mg per day. The UGT1A1*28 were examined by direct sequencing of DNA from peripheral whole blood. The UGT1A1*28 allele frequency was 11%. The cumulative incidence of any grade of hyperbilirubinemia was 77%, 89%, 98%, and 100%, at 3, 12, 24, and 30 months, respectively. The cumulative incidence of severe (grade 3-4) hyperbilirubinemia was 21%, 41%, 66%, and 75%, at 3, 12, 24, and 30 months, respectively. However, the point prevalence of severe hyperbilirubinemia did not increase with time and remained around 25%. Our data suggest that atazanavir-associated hyperbilirubinemia is common but transient in a population with low UGT1A1*28 allele frequency.

Milestones in history of adult vaccination in Korea

Vaccination is one of the most effective and cost-benefit interventions that reduced the mortality. Major vaccine preventable diseases have decreased dramatically after the introduction of immunization program in Korea. In this article, we review milestones in history of immunization program, especially in adult vaccination.