(An) analysis of the risk factors for healthcare associated infection in surgical intensive care unit

학위논문 (석사)-- 서울대학교 대학원 : 보건학과(보건학전공), 2011.8. 조성일.Maste

Comparison of the Microbiological Efficacy of Disinfection Using Ultraviolet and Hydrogen Peroxide System for Carbapenemase-producing Enterobacteriaceae in a Healthcare Setting

Background: This study aimed to compare the efficacy of microbiological disinfection between the ultraviolet-C (UV-C) device and aerosolized hydrogen peroxide (aHP) system in a healthcare setting. Methods: Four rooms were installed with two UV-C devices and two aHP systems. Thirty formica sheets contaminated with carbapenemase-producing Enterobacteriaceae (CPE) were placed in each room. After intervention, the median log10 reduction and modified decontamination rates were compared between the two methods using Rodac plates. Eight sink drains in the rooms previously occupied by a patient with CPE were sampled separately before and after the interventions. Results: The median log10 reduction was 5.52 and 5.37 after the UV-C (n=60) and aHP (n=60) interventions, respectively (P=0.86), whereas the modified decontamination rate was 50% and 45%, respectively (P=0.71). At the UV-direct sites, UV-C showed higher median log10 reduction (5.91 vs. 5.61, P=0.002) and modified decontamination rate (83% vs. 53%, P=0.03) than those of aHP. Conversely, at UV-indirect sites, aHP showed higher median log10 reduction (4.63 vs. 5.07%, P=0.02) and modified decontamination rate (17% vs. 37%, P=0.01) than those of UV-C. After the intervention, carbapenemase-resistant Gram-negative bacilli decreased further in five of the seven sink drains disinfected by sodium. Conclusion: Both UV-C and aHP reduced the bacterial contamination in the rooms. The aHP was significantly more effective than UV-C at the UV-indirect sites, and the converse was true for the UV-direct sites. Application of the intervention to disinfect the sink drains resulted in additional bacterial decontamination. Considering the features of the machines and the results of this study, healthcare facilities can choose either UV-C or aHP for decontamination

Frequency of and risk factors for reversion of QuantiFERON test in healthcare workers in an intermediate-tuberculosis-burden country

Objectives: High-risk healthcare workers (HCWs) are often screened for latent tuberculosis infection (LTBI) using QuantiFERON tests (QFTs), with annual serial tests often showing reversion from positive to negative results. We assessed the frequency of and risk factors for reversion of QFTs in HCWs in an intermediate-tuberculosis burden country. Methods: We enrolled high-risk HCWs at a tertiary-care hospital in South Korea, who were assessed by QFTs at least twice between 2017 and 2019. Results: Of the 1870 HCWs screened, 1542 (82%) had persistent negative results, 229 (12%) had persistent positive results, 53 (3%) showed reversion, and 46 (2%) showed conversion from negative to positive. Multivariate analysis comparing the characteristics of the 229 HCWs with persistent positive results and the 53 who experienced reversion showed that older age (adjusted odds ratio (aOR): 0.96; 95% confi-dence interval (CI): 0.92-0.99), male sex (aOR: 0.29; 95% CI: 0.11-0.78) and high (>0.70 IU/mL) baseline QFT results (aOR: 0.15; 95% CI: 0.07-0.31) were inversely associated with reversion. Using an ROC curve derived cut-off of <0.738 IU/mL, the area under the curve was 0.79. Of 53 HCWs with reversion, 36 (78%) had below 0.738 IU/mL of baseline QFT, while 181 (79%) of 229 HCWs without reversion had above 0.738 IU/mL of baseline QFT. Conclusion: Reversion during serial testing is unlikely in HCWs who are male, older in age, and have higher baseline QFT results. Serial testing without LTBI treatment may be indicated in HCWs who are female, younger and, especially, have lower QFT results. Ja Young Kim, Clin Microbiol Infect 2021;27:1120 (c) 2020 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved

Nosocomial Outbreak of COVID-19 in a Hematologic Ward

Background Coronavirus disease 2019 (COVID-19) outbreaks occur in hospitals in many parts of the world. In hospital settings, the possibility of airborne transmission needs to be investigated thoroughly. Materials and Methods There was a nosocomial outbreak of COVID-19 in a hematologic ward in a tertiary hospital, Seoul, Korea. We found 11 patients and guardians with COVID-19 through vigorous contact tracing and closed-circuit television monitoring. We found one patient who probably had acquired COVID-19 through airborne-transmission. We performed airflow investigation with simulation software, whole-genome sequencing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results Of the nine individuals with COVID-19 who had been in the hematologic ward, six stayed in one multi-patient room (Room 36), and other three stayed in different rooms (Room 1, 34, 35). Guardian in room 35 was close contact to cases in room 36, and patient in room 34 used the shared bathroom for teeth brushing 40 minutes after index used. Airflow simulation revealed that air was spread from the bathroom to the adjacent room 1 while patient in room 1 did not used the shared bathroom. Airflow was associated with poor ventilation in shared bathroom due to dysfunctioning air-exhaust, grill on the door of shared bathroom and the unintended negative pressure of adjacent room. Conclusion Transmission of SARS-CoV-2 in the hematologic ward occurred rapidly in the multi-patient room and shared bathroom settings. In addition, there was a case of possible airborne transmission due to unexpected airflow