Short-term exposure to benzalkonium chloride in bacteria from activated sludge alters the community diversity and the antibiotic resistance profile.

The continuous introduction of cleaning products containing benzalkonium chloride (BAC) from household discharges can mold the microbial communities in wastewater treatment plants (WWTPs) in a way still poorly understood. In this study, we performed an in vitro exposure of activated sludge from a WWTP in Costa Rica to BAC, quantified the changes in intI1, sul2, and qacE/qacEΔ1 gene profiles, and determined alterations in the bacterial community composition. The analysis of the qPCR data revealed elevated charges of antibiotic resistance genes in the microbial community; after BAC's exposure, a significant increase in the qacE/qacEΔ1 gene, which is related to ammonium quaternary resistance, was observed.

A Somatic Coliphage Threshold Approach To Improve the Management of Activated Sludge Wastewater Treatment Plant Effluents in Resource-Limited Regions.

Effective wastewater management is crucial to ensure the safety of water reuse projects and effluent discharge into surface waters. Multiple studies have demonstrated that municipal wastewater treatment with conventional activated sludge processes is inefficient for the removal of a wide spectrum of viruses in sewage. In this study, a well-accepted statistical approach was used to investigate the relationship between viral indicators and human enteric viruses during wastewater treatment in a resource-limited region.

Low-cost internal controls for detection of Giardia cysts in water samples.

Giardia cysts stained with hot carbolfuchsin were used as internal controls in a concentration method for surface water samples. The morphological integrity of stained cysts and the stain's stability and intensity were tested with each of the chemical reagents used in the aluminum sulfate flocculation method. No alterations in morphology or color were noted.

Enterococci as a key parameter for water quality index: Purires River, Costa Rica.

This study used the Canadian Water Quality Index (CWI) to characterize water sampled at three points within the Purires River micro basin, Costa Rica. The first sampling point is located in a high zone with domestic agricultural activities, the second point around the mid-point of the flow of the river, and the third point at the lowest zone with extensive agricultural activities mainly centered on the production of fresh vegetables. Eleven physicochemical parameters (As, Cd, Cr, biochemical oxygen demand (BOD), chemical oxygen demand (COD), NH , NO , Pb, pH, percent saturation of dissolved oxygen (PSO), and total suspended solids (TSS)) and two microbiological parameters (fecal coliforms and enterococci) were evaluated.

The importance of integrons for development and propagation of resistance in Shigella: the case of Latin America.

In Latin America, the disease burden of shigellosis is found to coexist with the rapid and rampant spread of resistance to commonly used antibiotics. The molecular basis of antibiotic resistance lies within genetic elements such as plasmids, transposons, integrons, genomic islands, etc., which are found in the bacterial genome.

Detection of shigella in lettuce by the use of a rapid molecular assay with increased sensitivity.

A Multiplex Polymerase Chain Reaction (PCR) assay to be used as an alternative to the conventional culture method in detecting Shigella and enteroinvasive Escherichia coli (EIEC) virulence genes ipaH and ial in lettuce was developed. Efficacy and rapidity of the molecular method were determined as compared to the conventional culture. Lettuce samples were inoculated with different Shigella flexneri concentrations (from 10 CFU/ml to 10(7) CFU/ml).

The CDRC principles of international health research.

The Comprehensive Drug Research Center (CDRC) at the University of Miami was established in the early 1970s. Through the decades, investigators from the CDRC have worked with investigators from several countries to establish joint research efforts. Countries often do not have the infrastructure or monetary resources to carry out research on their own.