IMPORTANCE There is limited information about the clinical course and viral load in asymptomatic patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).OBJECTIVE To quantitatively describe SARS-CoV-2 molecular viral shedding in asymptomatic and symptomatic patients. DESIGN, SETTING, AND PARTICIPANTSA retrospective evaluation was conducted for a cohort of 303 symptomatic and asymptomatic patients with SARS-CoV-2 infection between March 6 and March 26, 2020. Participants were isolated in a community treatment center in Cheonan, Republic of Korea.MAIN OUTCOMES AND MEASURES Epidemiologic, demographic, and laboratory data were collected and analyzed. Attending health care personnel carefully identified patients' symptoms during isolation. The decision to release an individual from isolation was based on the results of reverse transcription-polymerase chain reaction (RT-PCR) assay from upper respiratory tract specimens (nasopharynx and oropharynx swab) and lower respiratory tract specimens (sputum) for SARS-CoV-2. This testing was performed on days 8, 9, 15, and 16 of isolation. On days 10, 17, 18, and 19, RT-PCR assays from the upper or lower respiratory tract were performed at physician discretion. Cycle threshold (Ct) values in RT-PCR for SARS-CoV-2 detection were determined in both asymptomatic and symptomatic patients. RESULTSOf the 303 patients with SARS-CoV-2 infection, the median (interquartile range) age was 25 (22-36) years, and 201 (66.3%) were women. Only 12 (3.9%) patients had comorbidities (10 had hypertension, 1 had cancer, and 1 had asthma). Among the 303 patients with SARS-CoV-2 infection, 193 (63.7%) were symptomatic at the time of isolation. Of the 110 (36.3%) asymptomatic patients, 21 (19.1%) developed symptoms during isolation. The median (interquartile range) interval of time from detection of SARS-CoV-2 to symptom onset in presymptomatic patients was 15 (13-20) days. The proportions of participants with a negative conversion at day 14 and day 21 from diagnosis were 33.7% and 75.2%, respectively, in asymptomatic patients and 29.6% and 69.9%, respectively, in symptomatic patients (including presymptomatic patients). The median (SE) time from diagnosis to the first negative conversion was 17 (1.07) days for asymptomatic patients and 19.5 (0.63) days for symptomatic (including presymptomatic) patients (P = .07). The Ct values for the envelope (env) gene from lower respiratory tract specimens showed that viral loads in asymptomatic patients from diagnosis to discharge tended to decrease more slowly in the time interaction trend than those in symptomatic (including presymptomatic) patients (β = −0.065 [SE, 0.023]; P = .005). CONCLUSIONS AND RELEVANCEIn this cohort study of symptomatic and asymptomatic patients with SARS-CoV-2 infection who were isolated in a community treatment center in Cheonan, Republic of Korea, the Ct values in asymptomatic patients were similar to those in symptomatic patients. Isolation of asymptomatic patients may be necessary to control the spread o...

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of health care-associated infections. Vancomycin remains an acceptable treatment option. There has been a welcome increase in the number of agents available for the treatment of MRSA infection. These drugs have certain differentiating attributes and may offer some advantages over vancomycin, but they also have significant limitations. These agents provide some alternative when no other options are available.

The isolation of carbapenem-resistant Klebsiella pneumoniae (CRKP) has been increasingly reported. However, no study analyzing potential risk factors for the acquisition of CRKP has been published as of now. We therefore performed a case-control study to determine the risk factors for the acquisition of CRKP. CRKP was nosocomially isolated from 30 patients between January 1997 and August 2003. Control patients were randomly selected at a ratio of 4:1 from the same medical or surgical services from which patients were receiving care when isolation of CRKP occurred. Risk factors for CRKP were previous use of carbapenem (adjusted odds ratio [AOR], 28.68; 95% confidence interval [CI], 9.08-90.55) and cephalosporin (AOR, 4.10; 95% CI, 1.35-12.43). In contrast, previous use of fluoroquinolone was negatively associated with isolation of CRKP (AOR, 0.26; 95% CI 0.07-0.97); however, the possibility of selection bias cannot be ruled out. Our results suggest that the nosocomial isolation of CRKP is strongly favored by the selection pressure of carbapenem.

Penicillin-binding protein 4 (PBP4), a nonessential, low-molecular-weight penicillin-binding protein of Staphylococcus aureus, has been implicated in low-level resistance to ␤-lactam antibiotics, although the mechanism is unknown. Mutations in PBP4 and its promoter were identified in a laboratory-generated mutant strain, CRB, which expresses high-level resistance to ␤-lactams, including resistance to the newgeneration cephalosporins active against methicillin-resistant strains of S. aureus. These mutations did not appreciably alter the ␤-lactam antibiotic binding affinity of purified recombinant mutant PBP4 compared to that of wild-type PBP4. Compared to the susceptible parent strain, COLnex, the CRB strain produces a highly crosslinked cell wall peptidoglycan, indicative of increased transpeptidase activity. The pbp4 promoter mutation of CRB was associated with greatly increased amounts of PBP4 in membranes compared to those in the COLnex parent. Replacement of the native promoter of COLnex with the mutant promoter of CRB resulted in increased amounts of PBP4 in membranes and a highly cross-linked cell wall. PBP4 can be repurposed to provide essential transpeptidase activity in vivo and confer high-level resistance to ␤-lactam antibiotics, such as ceftobiprole and ceftaroline.

The clinical significance and virulence potential of Enterococcus casseliflavus/flavescens and Enterococcus gallinarum are still uncertain. We retrospectively analyzed 56 cases of significant bacteremia caused by E. casseliflavus or E. gallinarum. Of these cases, 25 (44.6%) were associated with polymicrobial bacteremia, and 43 (76.8%) were associated with entry via the biliary tract. Resistance to vancomycin was observed in 17 (30.4%) of these 56 patients, and this resistance was significantly associated with E. gallinarum bacteremia (adjusted odds ratio [AOR], 10.56; 95% confidence interval [CI], 2.41-46.27) and bacteremia without biliary tract origin (AOR, 6.74; 95% CI, 1.44-31.67). The crude mortality rate was 13%, and the bacteremia-related mortality rate was 1.9%. In conclusion, bacteremia due to E. casseliflavus and E. gallinarum is commonly associated with biliary tract disease and may be associated with a low risk of mortality.

Background This is an ongoing follow-up study (NCT02723773) evaluating persistence of efficacy and immune responses for six additional years in adults vaccinated with the glycoprotein E (gE)-based adjuvanted recombinant zoster vaccine (RZV) at ≥50 years of age in two pivotal efficacy trials (ZOE-50/70). The present interim analysis was performed after ≥2 additional years of follow-up (between 5.1 and 7.1 years [mean] post-vaccination) and includes partial data for year (Y)8 post-vaccination. Methods Annual assessments were performed for efficacy against herpes zoster (HZ) from Y6 post-vaccination onwards, and for anti-gE antibody concentrations and gE-specific CD4[2+] T-cell (expressing ≥2 of four assessed activation markers) frequencies from Y5 post-vaccination onwards. Results Of 7413 participants enrolled for the long-term efficacy assessment, 7277 (mean age at vaccination: 67.2 years), 813, and 108 were included in the cohorts for the evaluation of efficacy, humoral immune responses, and cell-mediated immune responses, respectively. Efficacy of RZV against HZ through this interim analysis was 84.0% (95% confidence interval [CI]: 75.9-89.8) from the start of this follow-up study and 90.9% (95%CI: 88.2-93.2) from vaccination in ZOE-50/70. Annual vaccine efficacy estimates were >84% for each year since vaccination and remained stable during this follow-up study through the interim analysis. Anti-gE antibody geometric mean concentrations and median frequencies of gE-specific CD4[2+] T cells had plateaued throughout this follow-up study up to the interim analysis, at ~6-fold above pre-vaccination levels. Conclusion Efficacy against HZ and immune responses to RZV remained high, suggesting that the clinical benefit of RZV in older adults is sustained for at least seven years post-vaccination.

The nephrotoxicity of colistin has been reported in the literature. A previous report has shown that acute kidney injury (AKI) occurred after an average of 13.5 days, but we have experienced that AKI developed with colistin administration earlier. We investigated clinical features of patients who developed AKI according to the time of AKI development after colistin use. We retrospectively collected the data of the patients who were admitted to 4 hospitals between January 2007 and May 2009. This study included 119 patients who had received intravenous colistin for over 72 h. We compared the early AKI group (AKI developed within 7 days) with the late AKI group. The patients’ age was 64.1 ± 14.0 years. AKI occurred in 65 of the 119 patients (54.6%). The duration of colistin use was 7.7 ± 6.4 days. AKI occurred in 46 patients within 7 days after colistin treatment and in 19 patients after 7 days. The patients with early AKI had a higher mortality rate than those with late AKI (OR: 4.37, 95% CI: 1.34, 14.18). In conclusion, clinicians might be cautioned that the mortality rate is higher for the patients with early occurrence of AKI than that for the patients with late occurrence of AKI.

Recently, the rate of nalidixic acid resistance in Korean clinical Salmonella strains markedly increased and it was partly due to the clonal spread of Salmonella Enteritidis, especially PT 1. The main mechanism of nalidixic acid resistance was a mutation in the gyrA region.