Assessing microbial risks of Escherichia coli: A spatial and temporal study of virulence and resistance genes in surface water in resource-limited regions.

Environmental microbial pollution can potentially cause illnesses and deaths among human populations. Environmental factors such as geomorphology, land use, human activities, and seasonality could influence pathogen dissemination. This study performed a space-temporal analysis of Escherichia coli concentrations, virulence (eaeA, bfpA, stx2, aatA, and st), and resistance (tetA, blaTEM, blaOXA, Intl-1, Intl-2, sul-1, and sul-2) genes in surface water within the Virilla sub-watershed, Costa Rica.

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.

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).