The impact of discontinuing single-room isolation of patients with vancomycin-resistant enterococci: a quasi-experimental single-centre study in South Korea.

OBJECTIVES: There is limited data on the effects of discontinuing single-room isolation while maintaining contact precautions, such as the use of gowns and gloves. In April 2021, our hospital ceased single-room isolation for patients with vancomycin-resistant enterococci (VRE) because of single-room unavailability. This study assessed the impact of this policy by examining the incidence of hospital-acquired VRE bloodstream infections (HA-VRE BSI). METHODS: This retrospective quasi-experimental study was conducted at a tertiary-care hospital in Seoul, South Korea. Time-series analysis was used to evaluate HA-VRE BSI incidence at the hospital level and in the haematology unit before (phase 1) and after (phase 2) the policy change. RESULTS: At the hospital level, HA-VRE BSI incidence level (VRE BSI per 1000 patient-days per month) and trend did not change significantly between phase 1 and phase 2 (coefficient -0.015, 95% confidence interval (CI): -0.053 to 0.023, P=0.45 and 0.000, 95% CI: -0.002 to 0.002, P=0.84, respectively). Similarly, HA-VRE BSI incidence level and trend in the haematology unit (-0.285, 95% CI: -0.618 to 0.048, P=0.09 and -0.018, 95% CI: -0.036 to 0.000, P = 0.054, respectively) did not change significantly across the two phases. CONCLUSIONS: Discontinuing single-room isolation of VRE-colonized or infected patients was not associated with an increase in the incidence of VRE BSI at the hospital level or among high-risk patients in the haematology unit. Horizontal intervention for multi-drug-resistant organisms, including measures such as enhanced hand hygiene and environmental cleaning, may be more effective at preventing VRE transmission.

Impact of carbapenem-targeted antimicrobial stewardship interventions: an interrupted time-series analysis.

BACKGROUND: The development of carbapenem-resistant Gram-negative bacilli (CR-GNB) is largely favoured by indiscriminate and prolonged carbapenem use, which is a significant contributing factor. AIM: To evaluate the impact of two carbapenem antibiotic stewardship programme interventions on both carbapenem prescriptions and the clinical isolation rates of CR-GNBs, using interrupted time-series analysis. METHODS: A time-series analysis was performed using data for carbapenem usage from a tertiary hospital in South Korea from January 2017 to July 2022. Two carbapenem antibiotic stewardship programme interventions were implemented sequentially: (i) a prospective audit and feedback (PAF) from November 2018 to April 2020 (intervention 1), and (ii) preauthorization from May 2020 to August 2020 (intervention 2). Monthly carbapenem usage and incidence of CR-GNB before and after each intervention were compared using an autoregressive integrated moving average model. FINDINGS: Implementation of PAF resulted in a significant reduction in carbapenem consumption, followed by an additional decrease after the preauthorization was implemented. The incidence of carbapenem-resistant Escherichia coli and Klebsiella pneumoniae increased after intervention 1, but there was a significant change from an increasing trend to a stationary trend after intervention 2. The incidence of carbapenem-resistant Pseudomonas aeruginosa, which had increased during the baseline period, became stationary after intervention 1. A significant decrease was observed in the incidence of carbapenem-resistant Acinetobacter baumannii during the implementation of intervention 1 and 2. CONCLUSION: This study emphasizes the importance of adopting comprehensive antibiotic management and rigorous infection control to prevent infections caused by antibiotic-resistant bacteria.

Risk of transmission of COVID-19 from healthcare workers returning to work after a 5-day isolation, and kinetics of shedding of viable SARS-CoV-2 variant B.1.1.529 (Omicron).

BACKGROUND: There have been limited data on the risk of onward transmission from individuals with Omicron variant infections who return to work after a 5-day isolation. AIM: To evaluate the risk of transmission from healthcare workers (HCWs) with Omicron variant who returned to work after a 5-day isolation and the viable-virus shedding kinetics. METHODS: This investigation was performed in a tertiary care hospital, Seoul, South Korea. In a secondary transmission study, we retrospectively reviewed the data of HCWs confirmed as COVID-19 from March 14th to April 3rd, 2022 in units with five or more COVID-19-infected HCWs per week. In the viral shedding kinetics study, HCWs with Omicron variant infection who agreed with daily saliva sampling were enrolled between February and March, 2022. FINDINGS: Of the 248 HCWs who were diagnosed with COVID-19 within 5 days of the return of an infected HCW, 18 (7%) had contact with the returned HCW within 1-5 days after their return. Of these, nine (4%) had an epidemiologic link other than with the returning HCW, and nine (4%) had contact with the returning HCW, without any other epidemiologic link. In the study of the kinetics of virus shedding (N = 32), the median time from symptom onset to negative conversion of viable virus was four days (95% confidence interval: 3-5). CONCLUSION: Our data suggest that the residual risk of virus transmission after 5 days of isolation following diagnosis or symptom onset is low.

Clustering and multiple-spreading events of nosocomial severe acute respiratory syndrome coronavirus 2 infection.

BACKGROUND: There is growing evidence that super-spreading events (SSEs) and multiple-spreading events (MSEs) are a characteristic feature of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, data regarding the possibility of SSEs or MSEs in healthcare settings are limited. METHODS: This study was performed at a tertiary-care hospital in Korea. We analysed the nosocomial COVID-19 cases that occurred in healthcare workers and inpatients and their caregivers between January and 20th December 2020. Cases with two to four secondary cases were defined as MSEs and those with five or more secondary cases as SSEs. FINDINGS: We identified 21 nosocomial events (single-case events, N = 12 (57%); MSE + SSE, N = 9 (43%)) involving 65 individuals with COVID-19. Of these 65 individuals, 21 (32%) were infectors. The infectors tended to have a longer duration between symptom onset and diagnostic confirmation than did the non-infectors (median two days vs zero days, P=0.08). Importantly, 12 (18%) individuals were responsible for MSEs and one (2%) for an SSE, which collectively generated 35 (54%) secondary cases. CONCLUSION: In a hospital with thorough infection-control measures, approximately 70% of the nosocomial cases of COVID-19 did not generate secondary cases, and one-fifth of the infectors were responsible for SSEs and MSEs, which accounted for approximately half of the total cases. Early case identification, isolation, and extensive contact tracing are important for the prevention of transmission and SSEs.

Upregulation of Fas and downregulation of CD94/NKG2A inhibitory receptors on circulating natural killer cells in patients with new-onset psoriasis.

BACKGROUND: Psoriasis has been considered as a T-helper 1 cell-mediated autoimmune disease driven by collaboration with multiple components of innate and acquired immune cells. Natural killer (NK) cells have been shown to bridge innate and acquired immunity, and thus could potentially contribute to the pathophysiology of psoriasis. OBJECTIVES: To investigate the phenotypic changes of circulating NK cells in patients with new-onset psoriasis. METHODS: Fifteen patients with plaque psoriasis (eight women and seven men) who visited our clinic after their first episode of psoriasis and did not have a history of previous systemic therapy or phototherapy participated in this study. Peripheral blood mononuclear cells were isolated and stained with a panel of antibodies against cell surface receptors expressed on T and/or NK cells and analysed by flow cytometry. RESULTS: As compared with normal healthy volunteers, patients with new-onset psoriasis showed no significant changes in numbers of peripheral NK, NK-T or T cells. NK activating receptors 2B4, CD48, NKG2D, CD16 and CD56 were found to be unchanged in new-onset psoriasis. However, the expression of Fas (activation-induced death receptor) was upregulated, whereas the expression of the NK inhibitory receptors CD94 and NKG2A was dramatically reduced on NK cells of new-onset psoriasis. These changes occurred at the level of mean fluorescent intensity, but minimally affected percentages of cells expressing Fas, CD94 and NKG2A. CONCLUSIONS: Our findings demonstrate that changes in the expression of Fas and CD94/NKG2A receptors on NK cells may occur during new-onset psoriasis, and are likely to contribute to the pathogenesis of psoriasis.

Detection of Helicobacter pylori DNA in human biliary tree and its association with hepatolithiasis.

Recently, several authors have reported that Helicobacter pylori DNA has been found in human bile. The aim of this study is to investigate the presence of H. pylori in the biliary tree of Koreans, including the bile, biliary epithelium, and gallstones. This study analyzed intrahepatic bile, bile duct tissue, and gallstones from 43 patients with hepatobiliary disease (PTCS group), gallbladder bile and tissue from 23 patients with gallbladder disease (CCT group), and eight patients without hepatobiliary disease (control group). H. pylori was examined by PCR with two different primers. PCR was positive in 4/43 (9.3%) by 26 kDa protein antigen primer and in 5/43 (11.6%) by urease A gene primer in bile from the PTCS group. However, in intrahepatic duct tissue, PCR was positive in only one case. PCR of gallbladder bile, tissue, and intrahepatic duct stones was negative. Upon intrahepatic bile analysis, the pH was significantly lower in PCR-positive than in negative cases (P < 0.05). In conclusion, H. pylori DNA may be present in the bile when there are certain environmental changes, such as lowered pH; however, H. pylori does not colonize the bile duct epithelium. We could find no pathogenetic role for H. pylori in the formation of hepatolithiasis.