Droplets generated from toilets during urination as a possible vehicle of carbapenem-resistant Klebsiella pneumoniae

Background In the health care setting, infection control actions are fundamental for containing the dissemination of multidrug-resistant bacteria (MDR). Carbapenemase-producing Enterobacterales (CPE), especially Klebsiella pneumoniae (CR-KP), can spread among patients, although the dynamics of transmission are not fully known. Since CR-KP is present in wastewater and microorganisms are not completely removed from the toilet bowl by flushing, the risk of transmission in settings where toilets are shared should be addressed. We investigated whether urinating generates droplets that can be a vehicle for bacteria and explored the use of an innovative foam to control and eliminate this phenomenon. Methods To study droplet formation during urination, we set up an experiment in which different geometrical configurations of toilets could be reproduced and customized. To demonstrate that droplets can mobilize bacteria from the toilet bowl, a standard ceramic toilet was contaminated with a KPC-producing Klebsiella pneumoniae ST101 isolate. Then, we reproduced urination and attached culture dishes to the bottom of the toilet lid for bacterial colony recovery with and without foam. Results Rebound droplets invariably formed, irrespective of the geometrical configuration of the toilet. In microbiological experiments, we demonstrated that bacteria are always mobilized from the toilet bowl (mean value: 0.11 ± 0.05 CFU/cm2) and showed that a specific foam layer can completely suppress mobilization. Conclusions Our study demonstrated that droplets generated from toilets during urination can be a hidden source of CR-KP transmission in settings where toilets are shared among colonized and noncolonized patients.

Extracellular Microenvironmental Change by B16F10 Melanoma-derived Proteins Induces Cancer Stem-like Cell Properties from NIH3T3 Cells

Cancer stem-like cells (CSCs) can generate solid tumors through the properties of stem cells such as self-renewal and differentiation and they cause drug resistance, metastasis and recurrence. Therefore, establishing CSC lines is necessary to conduct various studies such as on the identification of CSC origin and specific targeted therapies. In this study, we stimulated NIH3T3 fibroblasts to exhibit the characteristics of CSCs using the whole protein lysates of B16F10 melanoma cells. As a result, we induced colony formation that displayed self-renewal and differentiation capacities through anchorage-independent culture and re-attached culture. Moreover, colonies showed drug resistance by being maintained in the G0/G1 state. Colonies expressed various CSC markers and displayed high-level drug efflux capacity. Additionally, colonies clearly demonstrated tumorigenic ability by forming a solid tumor in vivo. These results show that proteins of cancer cells could transform normal cells into CSCs by increasing expression of CSC markers. This study argues the tremendous importance of the extracellular microenvironmental effect on the generation of CSCs. It also provides a simple experimental method for deriving CSCs that could be based on the development of targeted therapy techniques.

Proses Pengelolaan Air Limbah secara Biologis (Biofilm): Trickling Filter dan Rotating Biological Contactor (RBC)

Limbah adalah buangan yang kehadirannya tidak dikehendaki pada suatu tempat yang berada di lingkungan dan tidak mempunyai nilai ekonomi. Limbah dapat berupa cair, padat, dan gas. Tulisan ini akan membahas proses pengolahan limbah cair secara biologis yang merupakan proses tahapan pengolahan sekunder. Pengolahan limbah cair secara biologi bertujuan untuk membersihkan zat-zat organik atau mengubah zat organik yang berbahaya tersebut menjadi bentuk yang kurang/tidak berbahaya. Proses pengolahan air limbah secara biologis dapat diklasifikasikan menjadi tiga jenisyaitu proses biomassa tersuspensi (suspended culture), proses biomassa melekat (attached culture), dan lagoon/kolam. Tulisan ini akan membahas mengenai proses pengolahan air limbah melalui proses biomassa melekat (attached culture), yaitu trickling filter dan Rotating Biological Contactor (RBC)