Clinical Outcomes of Children With Extended-spectrum ß -Lactamase Urinary Tract Infection Receiving Discordant Empiric Antibiotic: A Comparative Study of Fever Duration, Length of Stay, and Readmissions.

There has been a recent increase in the incidence of urinary tract infections (UTIs) caused by extended spectrum beta-lactamase (ESBL) producing Enterobacteriaceae, which are resistant to third-generation cephalosporins. Our goal was to compare the clinical responses of patients with ESBL UTI and non-ESBL UTI who received empiric third-generation cephalosporins. A retrospective analysis was performed on data collected between June 1, 2013, and June 30, 2017, from children aged 0 days to 19 years old who presented to NYU Langone Long Island Hospital's pediatric ED and/or were admitted with a UTI caused by Enterobacteriaceae. There was no significant difference in median length of fever duration. However, ESBL patients had significantly longer hospital stays, higher 30-day readmission rate, and higher 7-day revisit rate. It is reasonable to maintain an empiric UTI antibiotic choice rather than selecting a broad-spectrum antibiotic, such as carbapenem for children at high risk of ESBL UTI.

DNA cytosine methyltransferase enhances viability during prolonged stationary phase in Escherichia coli.

In Escherichia coli, DNA cytosine methyltransferase (Dcm) methylates the second cytosine in the sequence 5'CCWGG3' generating 5-methylcytosine. Dcm is not associated with a cognate restriction enzyme, suggesting Dcm impacts facets of bacterial physiology outside of restriction-modification systems. Other than gene expression changes, there are few phenotypes that have been identified in strains with natural or engineered Dcm loss, and thus Dcm function has remained an enigma. Herein, we demonstrate that Dcm does not impact bacterial growth under optimal and selected stress conditions. However, Dcm does impact viability in long-term stationary phase competition experiments. Dcm+ cells outcompete cells lacking dcm under different conditions. Dcm knockout cells have more RpoS-dependent HPII catalase activity than wild-type cells. Thus, the impact of Dcm on stationary phase may involve changes in RpoS activity. Overall, our data reveal a new role for Dcm during long-term stationary phase.

The promises and challenges of patient-derived tumor organoids in drug development and precision oncology.

In the era of precision medicine, cancer researchers and oncologists are eagerly searching for more realistic, cost effective, and timely tumor models to aid drug development and precision oncology. Tumor models that can faithfully recapitulate the histological and molecular characteristics of various human tumors will be extremely valuable in increasing the successful rate of oncology drug development and discovering the most efficacious treatment regimen for cancer patients. Two-dimensional (2D) cultured cancer cell lines, genetically engineered mouse tumor (GEMT) models, and patient-derived tumor xenograft (PDTX) models have been widely used to investigate the biology of various types of cancers and test the efficacy of oncology drug candidates. However, due to either the failure to faithfully recapitulate the complexity of patient tumors in the case of 2D cultured cancer cells, or high cost and untimely for drug screening and testing in the case of GEMT and PDTX, new tumor models are urgently needed. The recently developed patient-derived tumor organoids (PDTO) offer great potentials in uncovering novel biology of cancer development, accelerating the discovery of oncology drugs, and individualizing the treatment of cancers. In this review, we will summarize the recent progress in utilizing PDTO for oncology drug discovery. In addition, we will discuss the potentials and limitations of the current PDTO tumor models.