Scientists at Penn State's College of Agricultural Sciences may soon have a new tool to detect harmful bacteria, according to a recent study published in the Journal of Microbiological Methods. The research introduces a novel technique called the enzyme-linked chaperone assay (ELCA), designed to detect Pseudomonas syringae, a bacterium that infects a wide range of crops, vegetables, and ornamental plants. This method is similar in cost to the commonly used enzyme-linked immunosorbent assay (ELISA), but it offers a key advantage: it can specifically detect living bacteria, making it more sensitive and accurate. Rachel Herschlag, the lead author of the study and a doctoral graduate in plant pathology at Penn State, explained that the research serves as a proof of concept. She noted that the method could be adapted in the future to detect other types of bacteria, including those that affect animals and humans. "This could expand its use in clinical, agricultural, environmental, and biotechnology settings," she said. The ELCA method works by mimicking the way bacteria invade their hosts. Carolee Bull, a professor of bacterial systematics and plant pathology and co-author of the paper, explained that traditional diagnostic tests like ELISA use antibodies derived from animals. In contrast, ELCA uses a bacterial chaperone protein that binds to a specific effector protein produced by the bacteria. This binding causes a colorless solution to turn yellow, providing a clear visual signal that the target bacteria are present. The technique is highly specific and can reliably identify its intended target. Effectors are proteins that help bacteria bypass the immune defenses of their hosts. These proteins are only produced by living bacteria, and they tend to break down quickly after the bacteria die. According to Herschlag, this means that ELCA can distinguish between living and dead bacteria. "Living bacteria showed higher detection levels than dead ones, which means the test can identify bacteria that are actually capable of causing infections," she said. Looking ahead, the researchers aim to refine the test by reducing background noise and adapting the method for other pathogens with similar chaperone-effector systems. These could include bacteria relevant to agriculture, veterinary science, and human health. The development of ELCA represents a promising step forward in the field of bacterial detection and diagnosis.