Moran Ki

2015 MERS outbreak in Korea: hospital-to-hospital transmission.

The distinct characteristic of the Middle East Respiratory Syndrome (MERS) outbreak in South Korea is that it not only involves intra-hospital transmission, but it also involves hospital-to-hospital transmission. It has been the largest MERS outbreak outside the Middle East, with 186 confirmed cases and, among them, 36 fatal cases as of July 26, 2015. All confirmed cases are suspected to be hospital-acquired infections except one case of household transmission and two cases still undergoing examination. The Korean health care system has been the major factor shaping the unique characteristics of the outbreak. Taking this as an opportunity, the Korean government should carefully assess the fundamental problems of the vulnerability to hospital infection and make short- as well as long-term plans for countermeasures. In addition, it is hoped that this journal, Epidemiology and Health, becomes a place where various topics regarding MERS can be discussed and shared.

Acute Pyelonephritis Among Adults: Cost of Illness and Considerations for the Economic Evaluation of Therapy

Urinary tract infection (UTI) is an infection anywhere in the urinary tract, most commonly due to bacteria. If infection involves the kidney, the UTI is termed acute pyelonephritis (APN). An estimated 10–30% of all patients with APN are hospitalised for treatment; in the US, the incidence of hospitalisation is 11.7 per 10 000 for women and 2.4 per 10 000 for men. Perhaps because of the generally good prognosis of APN when treated with current antibacterial therapies, there have been relatively few studies of patient management and therapeutic options for the disease, or of its epidemiology and risk factors.The most cost-effective outpatient management strategy (immediate discharge, observation followed by discharge, etc.) is currently unknown. Appropriate antimicrobial selection is clearly important, as treatment failures will increase the cost of care and result in additional morbidity for patients. The direct and indirect costs of APN are significant: an estimated

A nationwide seroepidemiology of hepatitis C virus infection in South Korea

US2.14 billion (year 2000 values). Cost estimates are most sensitive to hospitalisation rates, which are unknown in the US. Additional studies are needed to better define when in-hospital treatment is required. As the pathogens causing APN are increasingly becoming resistant to current therapies, not only are clinical trials in order to test the effectiveness of alternative therapies, but epidemiological studies to identify risk factors for infection with a resistant isolate and effective prevention strategies are required, especially among those with previous episodes of APN.

Epidemiology of group B streptococcus in Korean pregnant women.

The aim of this study was to reveal nationwide seroprevalence of HCV infection in South Korea by a large‐scale survey.

Antibiotic resistance and pyelonephritis.

Between January 2006 and May 2008, 2624 pregnant S. Korean women between 35-37 weeks gestation were screened for group B streptococcus (GBS). Resistance to antimicrobials was tested by disk diffusion and serotype determined using co-agglutination assays and microarray methods. Overall, 8% of pregnant women were colonized. Serotype III was the predominant serotype (43.8%), followed by serotypes V (20.3%), Ia (12.1%), and Ib (9.5%). GBS was frequently resistant to clindamycin (54.0%) and erythromycin (25.6%); 3.7% were resistant to cefazolin. More than three-quarters of serotype V were resistant to clindamycin or erythromycin or both, and 71% of serotype III were resistant to clindamycin but only 12% were resistant to erythromycin. GBS prevalence exceeded earlier reports by one-third. This is the first report of cefazolin resistance in Korea. These results underscore the need to establish screening measures and chemoprophylaxis guidelines regarding GBS infections in Korea.

Changing Molecular Epidemiology of Group B Streptococcus in Korea

Increasing antibiotic resistance threatensour ability to effectively treat bacterial in-fections. Antibiotic therapy enhances thegrowth of existing drug-resistant bacteriaand the exchange of resistance mecha-nisms between bacteria (and evenbetweenspecies) and selects for resistance muta-tions. The effect on levels of drug-resistantinfection in the population of treating1000 people with antibiotics for 1 day isroughly equivalent to treating 1 personwith antibiotics for 1000 days. Further-more, antibiotic therapy selects for drugresistance, not only in the pathogen, butin commensal bacteria that are present inthe patient, thereby creating a resistancereservoir. Thus, it is important to monitordrug resistance patterns among pathogenscausing common bacterialinfections,suchas urinary tract infection (UTI).Every year, 12% of women and 3% ofmen in the United States experience a UTI[1]. UTI is the most common bacterialinfection among adults in the community,and it is the most common health care–associated infection. Because UTI is usu-ally easily treated with antibiotics, it is easyto forget that UTI is often a source ofbacteremia and sepsis and can be fatal.Among men hospitalized for pyelone-phritis, the mortality rate is 16.5 deathsper 1000 hospitalizations; for women, thefigure is lower but is still substantial: 7.3deaths per 1000 hospitalizations [2]. Uro-pathogens in the community and in hos-pitals are increasingly resistant to antibi-otics; furthermore, because the infectionis so common, it is likely that antibiotictherapy for UTI is an important selectivefactor for antibiotic resistance at the pop-ulation level.Pyelonephritis is the most severe man-ifestation of UTI. There are surprisinglyfew studies of therapy for this disease orof the epidemiology and risk factors forpyelonephritis; therefore, it is welcome tosee the study of the epidemiology of py-elonephritis by Czaja et al. [3] in this issueof

The frequency of genes encoding three putative group B streptococcal virulence factors among invasive and colonizing isolates

The prevalence of group B streptococcus (GBS) among pregnant women and disease burdens in neonates and adults are increasing in Korea. Colonizing isolates, collected by screening pregnant women (n=196), and clinical isolates collected from clinical patients throughout Korea (n=234), were serotyped and screened for antibiotic resistance. Serotype III (29.8%) and V (27.7%) predominated, followed by Ia (17.0%). Antibiotic resistance was higher among clinical than colonizing isolates for erythromycin (35.1% and 26.9%; P=0.10) and for clindamycin (49.4% and 42.1%; P=0.17). erm(B) occurred in 91.9% of erythromycin resistant isolates, and 84.0% of isolates resistant to clindamycin. Only five isolates (4.2%) resistant to erythromycin were susceptible to clindamycin; by contrast, and unique to Korea, 34% of isolates resistant to clindamycin were erythromycin susceptible. Among these 60 erythromycin-susceptible & clindamycin-resistant isolates, 88% was serotype III, and lnu(B) was found in 89% of strains. Four fifths of the serotype V isolates were resistant to both erythromycin and clindamycin. Further characterization of the genetic assembly of these resistance conferring genes, erm(B) and lnu(B), will be useful to establish the clonal lineages of multiple resistance genes carrying strains.

Transmission of Seasonal Outbreak of Childhood Enteroviral Aseptic Meningitis and Hand-foot-mouth Disease

BackgroundGroup B Streptococcus (GBS) causes severe infections in very young infants and invasive disease in pregnant women and adults with underlying medical conditions. GBS pathogenicity varies between and within serotypes, with considerable variation in genetic content between strains. Three proteins, Rib encoded by rib, and alpha and beta C proteins encoded by bca and bac, respectively, have been suggested as potential vaccine candidates for GBS. It is not known, however, whether these genes occur more frequently in invasive versus colonizing GBS strains.MethodsWe screened 162 invasive and 338 colonizing GBS strains from different collections using dot blot hybridization to assess the frequency of bca, bac and rib. All strains were defined by serotyping for capsular type, and frequency differences were tested using the Chi square test.ResultsGenes encoding the beta C protein (bac) and Rib (rib) occurred at similar frequencies among invasive and colonizing isolates, bac (20% vs. 23%), and rib (28% vs. 20%), while the alpha (bca) C protein was more frequently found in colonizing strains (46%) vs, invasive (29%). Invasive strains were associated with specific serotype/gene combinations.ConclusionNovel virulence factors must be identified to better understand GBS disease.

Epidemiologic features of the first MERS outbreak in Korea: focus on Pyeongtaek St. Mary’s Hospital

This study was conducted to evaluate the modes of transmission of aseptic meningitis (AM) and hand-foot-mouth disease (HFMD) using a case-control and a case-crossover design. We recruited 205 childhood AM and 116 HFMD cases and 170 non-enteroviral disease controls from three general hospitals in Gyeongju, Pohang, and Seoul between May and August in both 2002 and 2003. For the case-crossover design, we established the hazard and non-hazard periods as week one and week four before admission, respectively. In the case-control design, drinking water that had not been boiled, not using a water purifier, changes in water quality, and contact with AM patients were significantly associated with the risk of AM (odds ratio [OR]=2.8, 2.9, 4.6, and 10.9, respectively), while drinking water that had not been boiled, having a non-water closet toilet, changes in water quality, and contact with HFMD patients were associated with risk of HFMD (OR=3.3, 2.8, 6.9, and 5.0, respectively). In the case-crossover design, many life-style variables such as contact with AM or HFMD patients, visiting a hospital, changes in water quality, presence of a skin wound, eating out, and going shopping were significantly associated with the risk of AM (OR=18.0, 7.0, 8.0, 2.2, 22.3, and 3.0, respectively) and HFMD (OR=9.0, 37.0, 11.0, 12.0, 37.0, and 5.0, respectively). Our findings suggest that person-to-person contact and contaminated water could be the principal modes of transmission of AM and HFMD.

What do we really fear? The epidemiological characteristics of Ebola and our preparedness

OBJECTIVES: This study investigated the epidemiologic features of the confirmed cases of Middle East Respiratory Syndrome (MERS) in Pyeongtaek St. Mary’s Hospital, where the outbreak first began, in order to identify lessons relevant for the prevention and control of future outbreaks. METHODS: The patients’ clinical symptoms and test results were collected from their medical records. The caregivers of patients were identified by phone calls. RESULTS: After patient zero (case #1) was admitted to Pyeongtaek St. Mary’s Hospital (May 15-May 17), an outbreak occurred, with 36 cases between May 18 and June 4, 2015. Six patients died (fatality rate, 16.7%). Twenty-six cases occurred in the first-generation, and 10 in the second-generation. The median incubation period was five days, while the median period from symptom onset to death was 12.5 days. While the total attack rate was 3.9%, the attack rate among inpatients was 7.6%, and the inpatients on the eighth floor, where patient zero was hospitalized, had an 18.6% attack rate. In contrast, caregivers and medical staff showed attack rates of 3.3% and 1.1%, respectively. CONCLUSIONS: The attack rates were higher than those of the previous outbreaks in other countries. The outbreak spread beyond Pyeongtaek St. Mary’s Hospital when four of the patients were moved to other hospitals without appropriate quarantine. The best method of preventing future outbreaks is to overcome the vulnerabilities observed in this outbreak, such as ward crowding, patient migration without appropriate data sharing, and the lack of an initial broad quarantine.