Park SY, et al. Infect Chemother. 2024 Aug;56:e35. https://doi.org/10.3947/ic.2024.0038

The purpose of this study is to determine the correlation between use of antimicrobials, such as fluoroquinolone, cefoxitin, and cefotaxime, and Escherichia coli resistance using a nationwide database. Nationwide data on antimicrobial consumption for 12 years (2002 to 2013) were acquired from a database of subjects (n = 1,025,340) included in the National Health Insurance Service-National Sample Cohort. National antimicrobial resistance rates of E. coli were obtained from the Korean Antimicrobial Resistance Monitoring System, which has been administered by the Korean Centers for Disease Control and Prevention since 2002. Fluoroquinolone-resistance rates of E. coli isolated from general hospitals have continuously increased since 2002 and were correlated with nationwide fluoroquinolone use (r = 0.82, P = 0.0012) or ciprofloxacin use (r = 0.90, P<0.0001). Cefotaxime-resistance rates of E. coli isolated from general hospitals markedly increased since 2008 and were correlated with nationwide cefotaxime use (r = 0.94, P<0.0001) or third-generation cephalosporin use (r = 0.96, P<0.0001). Cefoxitin-resistance rates of E. coli isolated from general hospitals peaked in 2010 and significantly correlated with cephamycin use at a two-year interval (r = 0.64, P = 0.0256). In conclusion, consumption of antimicrobials such as fluoroquinolone, cefoxitin, and cefotaxime is well correlated with the resistance rates of E. coli to these agents. This study provides background data for national antimicrobial management policies to reduce antimicrobial resistance.

The aim of this study was to elucidate patterns of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) clearance in the natural course of asymptomatic coronavirus disease 2019 (COVID-19). Consecutive patients with non-severe COVID-19 were included retrospectively. Asymptomatic patients with a normal body temperature and no evidence of pneumonia throughout the disease course were assigned to the asymptomatic group. The reverse transcription PCR (RT-PCR) assay was repeated every two to five days after the first follow-up RT-PCR assay. Negative conversion was defined as two consecutive negative RT-PCR assay results within a 24-h interval. Rebound of the cycle threshold (Ct) value was defined as negative from the single RT-PCR assay and positive from the following assay. Among a total of 396 patients identified (median age 42.5 years (interquartile range (IQR) 25.0–55.0 years), 35.6% male), 68 (17.2%) were assigned to the asymptomatic group and 328 (82.8%) to the symptomatic group. The time until negative conversion was significantly shorter in the asymptomatic group than in the symptomatic group: median 14.5 days (IQR 11.0–21.0 days) and 18.0 days (IQR 15.0–22.0 days), respectively (p = 0.001). Rebound of Ct values was observed in 78 patients (19.7%). Time until negative conversion is shorter in asymptomatic COVID-19 than in symptomatic COVID-19. Rebound of Ct values is not uncommon.

National antimicrobial usage and prescription patterns during the 12 years from 2002 to 2013 were analyzed using the National Health Insurance Service-National Sample Cohort. Antimicrobial usage was analyzed by major illness, sex, age, area of residence, income rank, diagnosis, and type of medical institution for each year. Total antimicrobial prescriptions increased from 15.943 daily defined dose (DDD)/1,000 inhabitants/day in 2002 to 24.219 in 2013. In 2013, 72% of total prescriptions were administered in clinics. Antimicrobials were most frequently prescribed to children younger than 10 years, followed by adults aged 70 years or older and those aged 60–69 years. Penicillins and cephems were the most popular classes of antimicrobial used. In 2013, 48% of total antibiotic usage (11.683 DDD/1,000 inhabitants/day) was due to respiratory diseases. After the Korean government has implemented a series of healthcare policies, antibiotic prescription decreased for the treatment of upper respiratory infection, the causative agents are mostly viruses.

Antimicrobial resistance is becoming one of the greatest challenges to public health worldwide. Infections by antimicrobial-resistant organisms could result in the failure of treatment, increased medical costs, prolonged hospital stays, and an increased socioeconomic burden. Antimicrobial usage in Korea remains heavy, even after much effort to reduce their use. According to the Korean antimicrobial resistance surveillance system, the resistance rates of many bacteria are increasing. The resistance rate of Acinetobacter baumannii to imipenem in Korea increased to 85% in 2015, representing a major public threat. The reports of increased carbapenem resistance in Enterobacteriaceae are worrisome. More importantly, some carbapenem-resistant Enterobacteriaceae may result from the production of carbapenemases, which break down carbapenems. There are relatively few treatment options for extensively drug-resistant A. baumannii and carbapenem-resistant Enterobacteriaceae. Most reports are retrospective observational studies. Because there are little published data from randomized controlled trials, more data assessing antimicrobial treatment for extensively drug-resistant A. baumannii and carbapenem-resistant Enterobacteriaceae are needed to make treatment recommendations.

The purpose of this study is to identify the factors related to the infection and/or colonization of carbapenemase-producing Enterobacterales (CPE) based on clinical and microbiological data for patients in the intensive care unit (ICU). All patients admitted to medical ICU were screened for CPE on admission and weekly, and this 1:2 case–control study included patients with CPE identified by screening or clinical cultures from 2017 to 2018. The clonal relatedness was evaluated by pulsed-field gel electrophoresis (PFGE). A total of 45 CPE patients were identified with a prevalence of 3.8%. The most frequent organism was Klebsiella pneumoniae (69%) and the carbapenemases belonged to the class A Klebsiella pneumoniae Carbapenemase (KPC-2) (87%), class B New Delhi Metallo-β-lactamase (NDM) (11%), and Imipenemase (IMP-1) (2%) strains. The PFGE profiles showed two large clustered groups of KPC-2-producing K. pneumoniae. In the multivariate analysis, pneumonia/chronic pulmonary disease, previous fluoroquinolone use, and previous use of nasogastric tube were the significant risk factors for CPE infection or colonization in ICU-admitted patients. Critical illness and underlying medical conditions such as pneumonia/chronic pulmonary disease, antimicrobial selective pressure, and the use of a medical device are identified as risk factors for CPE infection or colonization in ICU. Person to person transmission also contributed.