Improved detection of antibiotic compounds by bacterial reporter strains achieved by manipulations of membrane permeability and efflux capacity

Illuminating Progress: The Contribution of Bioluminescence to Sustainable Development Goal 6-Clean Water and Sanitation-Of the United Nations 2030 Agenda

The United Nations Agenda 2030 Sustainable Development Goal 6 (SDG 6) aims at ensuring the availability and sustainable management of water and sanitation. The routine monitoring of water contaminants requires accurate and rapid analytical techniques. Laboratory analyses and conventional methods of field sampling still require considerable labor and time with highly trained personnel and transport to a central facility with sophisticated equipment, which renders routine monitoring cumbersome, time-consuming, and costly. Moreover, these methods do not provide information about the actual toxicity of water, which is crucial for characterizing complex samples, such as urban wastewater and stormwater runoff. The unique properties of bioluminescence (BL) offer innovative approaches for developing advanced tools and technologies for holistic water monitoring. BL biosensors offer a promising solution by combining the natural BL phenomenon with cutting-edge technologies. This review provides an overview of the recent advances and significant contributions of BL to SDG 6, focusing attention on the potential use of the BL-based sensing platforms for advancing water management practices, protecting ecosystems, and ensuring the well-being of communities.

Bacterial Multidrug Efflux Pumps at the Frontline of Antimicrobial Resistance: An Overview

Multidrug efflux pumps function at the frontline to protect bacteria against antimicrobials by decreasing the intracellular concentration of drugs. This protective barrier consists of a series of transporter proteins, which are located in the bacterial cell membrane and periplasm and remove diverse extraneous substrates, including antimicrobials, organic solvents, toxic heavy metals, etc., from bacterial cells. This review systematically and comprehensively summarizes the functions of multiple efflux pumps families and discusses their potential applications. The biological functions of efflux pumps including their promotion of multidrug resistance, biofilm formation, quorum sensing, and survival and pathogenicity of bacteria are elucidated. The potential applications of efflux pump-related genes/proteins for the detection of antibiotic residues and antimicrobial resistance are also analyzed. Last but not least, efflux pump inhibitors, especially those of plant origin, are discussed.

A Smartphone-Based Whole-Cell Array Sensor for Detection of Antibiotics in Milk

We present an integral smartphone-based whole-cell biosensor, LumiCellSense (LCS), which incorporates a 16-well biochip with an oxygen permeable coating, harboring bioluminescent Escherichia coli bioreporter cells, a macro lens, a lens barrel, a metal heater tray, and a temperature controller, enclosed in a light-impermeable case. The luminescence emitted by the bioreporter cells in response to the presence of the target chemicals is imaged by the phone’s camera, and a dedicated phone-embedded application, LCS_Logger, is employed to calculate photon emission intensity and plot it in real time on the device’s screen. An alert is automatically given when light intensity increases above the baseline, indicating the presence of the target. We demonstrate the efficacy of this system by the detection of residues of an antibiotic, ciprofloxacin (CIP), in whole milk, with a detection threshold of 7.2 ng/mL. This value is below the allowed maximum as defined by European Union regulations.

Methods for field measurement of antibiotic concentrations: limitations and outlook

The growing prevalence of antibiotic resistance poses an increasingly serious threat to human health. Although an important driver of antibiotic resistance is the continuous exposure of bacteria to sublethal concentrations of antibiotics in natural environments, antibiotic pollutants are not currently tracked globally or systematically. This limits the international capacity to address the rise of antibiotic resistance at its source. To address this lack of data, the development of methods to measure antibiotic concentrations on-site is essential. These methods, ideally, must be sensitive to sublethal concentrations of antibiotics and require minimal technical expertise. Furthermore, factors such as cost, selectivity, biosafety and the ability to multiplex must be evaluated in the context of field use. Based on these criteria, we provide a critical review of current methods in antibiotic detection and evaluate their adaptability for use on-site. We categorize these methods into microbiological assays, physical and chemical assays, immunoassays, aptasensors and whole-cell biosensors. We recommend continued development of a dipstick or microfluidics approach with a bacterial promoter-based mechanism and colorimetric output. This technique would incorporate the advantageous aspects of existing methods, maximize shelf-life and ease-of-use, and require minimal resources to implement in the field.

Microbial biosensing of ciprofloxacin residues in food by a portable lens-free CCD-based analyzer

We present a rapid and simple approach for sensitive detection of antibiotic residues in food samples based on luminescence induction by live bacterial sensor strains integrated into a CCD-based lens-free optical analyzer (LumiSense). Using ciprofloxacin as a model antibiotic, we demonstrate response times of between 20 and 80 min, and detection thresholds of 8 ng/mL for milk, egg white, and chicken essence, and 64 ng/mL for egg yolk. These values are below the minimal allowed values as defined by European Union regulations. Although not intended to replace traditional analytical equipment and regulation-approved methods, LumiSense and similar systems, sample preparation for which involves only simple mixing, dilution, and homogenization, may nevertheless provide a simple means for high-throughput food sample screening. Graphical abstract Detection of bioluminescence from genetically modified bacteria offers a simple and effective way for monitoring an antibiotic, ciprofloxacin, in milk without prior sample preparation.

Recent Advances in Genetic Technique of Microbial Report Cells and Their Applications in Cell Arrays

Microbial cell arrays have attracted consistent attention for their ability to provide unique global data on target analytes at low cost, their capacity for readily detectable and robust cell growth in diverse environments, their high degree of convenience, and their capacity for multiplexing via incorporation of molecularly tailored reporter cells. To highlight recent progress in the field of microbial cell arrays, this review discusses research on genetic engineering of reporter cells, technologies for patterning live cells on solid surfaces, cellular immobilization in different polymers, and studies on their application in environmental monitoring, disease diagnostics, and other related fields. On the basis of these results, we discuss current challenges and future prospects for novel microbial cell arrays, which show promise for use as potent tools for unraveling complex biological processes.