The discovery of bacteriophages allowed the development of new ways to control the bacterial number and to assess bacterial viability. The most obvious application of bacteriophages is the treatment of human bacterial infections (phage therapy). The advantage of phage therapy is the extreme specificity of phages, since they interact with and infect only certain bacteria without affecting other bacteria or cell lines of other organisms. The advances in phage biology led to the widespread use of specific phage–host interactions in medicine and the agricultural and food industries. Thus, bacteriophages are an alternative to antibiotics for fighting infections and destroying pathogenic bacteria. This work has demonstrated for the first time the potential of a compact acoustic sensor system for assessing the impact of bacteriophages on microbial cells and the bacteriophage sensitivity of the latter. It has been shown that the developed system can be used to evaluate the activity of bacteriophages against microbial cells within 5 min without taking into account the time of cultivation of microbial cells for analysis. The results obtained are promising for further development of the acoustic sensory system in phage therapy.

Outbreaks of viral infectious diseases in humans and animals remain one of the global problems of our time. Therefore, one of the most popular areas in applied microbiology is the development of fast and sensitive methods for determining viruses, including those based on biosensor analysis methods. The promise of acoustic sensor systems for detecting viruses is described in this work. The optimal capabilities of electroacoustic sensors in detecting viruses, the possibility of conducting analysis in the presence of interfering factors (viral particles and microflora), and the repeated use of sensors are shown. The promise of using acoustic sensors to determine viruses in microbiology, medicine, and veterinary medicine is demonstrated.

The possibility of express analysis of the effect of aminoglycoside antibiotics on bacteria ( Escherichia coli ) using a sensor system based on a piezoelectric resonator with a lateral electric field with an operating frequency range of 6–7 MHz is shown. E.coli strains, both sensitive and resistant to kanamycin were used for the experiments. During evaluating the kanamycin effect on bacteria, the change in the electrical impedance modulus of the resonator was used as an analitical signal. It has been established that the criterion for the antibiotic bacteria sensitivity is the change in the modulus of the sensor electrical impedance after antibiotic exposure on bacteria at any frequency near the resonance. The sensor is highly sensitive and allows diagnosing the antimicrobial susceptibility of bacteria within 7–9 minutes.

Recombinant antibodies specific to kanamycin were obtained using a sheep display library of scFv fragments (Griffin.1) and the possibility of their use for the determination of kanamycin by dot-immunoassay was demonstrated. The minimum detectable concentration of kanamycin was 1 μg/mL (distinguishable label binding other than background). It has been shown that anti-kanamycin phage antibodies are specific for kanamycin and do not interact with other antibiotics (neomycin, tetracycline, ampicillin, and gentamicin). Anti-kanamycin phage antibodies are a promising alternative to monoclonal antibodies for use in the determination of kanamycin.

Use of large numbers of antibacterial drugs leads to increased pollution of the environment, especially water resources. Therefore, it is important to devise methods for the rapid detection and determination of antibiotics in aqueous solutions. We describe a microbial sensor system that is based on a resonator with a lateral electric field and is intended for the rapid detection and determination of kanamycin in aqueous solutions. Kanamycin was selectively determined in a solution with a conductivity of 1300 μS/cm. The lower detection limit was 0.5 μg/mL, and the analysis time was less than 5 min. The change in the electric impedance modulus of the sensor after kanamycin action on the bacteria served as an analytical signal. This sensor system is promising, because it can be used repeatedly and does not require immobilization of the analysis components on the sensor surface.

Ampicillin-specific antibodies were obtained using a sheep display library of scFv fragments (Griffin.1, UK). Ampicillin was determined by dot-immunoassay with biospecific interaction of selected recombinant antibodies in phage format (phage antibodies). It has been established that the phage antibodies are specific for ampicillin and do not interact with other antibiotics as tetracycline and kanamycin, as well as with substances similar in chemical formula, that is, L-phenylalanine, L-tryptophan, and L-cysteine. It has been shown that the method of solid-phase immunoassay with visual consideration of the results makes detection of ampicillin with the minimum concentration of 1 μg/mL possible. Phage antibodies are promising for use as a sensitive (recognizing) element of sensory systems at the ampicillin detection.

Antibacterial drugs are some of the most important medications used in health and veterinary medicine. The widespread use of antibiotics has led to significant pollution of the environment and water resources, in particular . In this regard, the problem of controlling antibiotic content in dosage forms, as well as their detection in liquids, food products, waste waters of pharmaceutical enterprises, and the other objects, is urgent. Microbiological, spectrophotometric, fluorimetric, chemiluminescent, chromatographic, as well as biodetection methods are used to identify antibiotics. The article provides a brief overview of methods and approaches for the detection of antibiotics. Progress in the development of biosensor systems for the analysis of antibiotics has been shown.

A biological sensor for the determination of ampicillin in conductive solutions is presented. The sensor is based on an acoustic slot mode in a structure consisting of two lithium niobate piezoplates of different cuts separated by an air gap. One of the piezoplates serves as the bottom of a liquid container into which a suspension of microbial cells sensitive to the antibiotic under study is introduced. The depth of resonant peaks in the frequency response of the total loss of the sensor is measured. After that, the studied antibiotic is added to the container and the measurements are repeated. An analytical signal indicating the appearance of an antibiotic in the cell suspension is the change in the depth of resonance peaks after it is added to the container.

A microbial test-system for real-time determination of low/residual concentrations of kanamycin in a liquid without the need for special labels is presented. The main element of the system was a piezoelectric resonator excited by a lateral electric field based on an X-cut lithium niobate plate 0.5 mm thick with two rectangular electrodes on one side. On the other side of the resonator, there was a 1.5 ml liquid container. As a sensory element we used Escherichia coli B-878 microbial cells, which are sensitive to kanamycin. For measurement 1 ml of this cells suspension was placed in a liquid container and then the test liquid in the amount of 2 μl containing kanamycin was added. The change in the real part of the electrical impedance of the resonator before and after the test liquid addition was used as an analytical signal which indicated the presence of kanamycin. The lower limit of determination of kanamycin turned out to be 1.0 μg/ml with an analysis time of 10 min. The test-system allows to detect kanamycin in the presence of such antibiotic as ampicillin and polymixin.

The possibility of antibacterial activity assay using an acoustic non-contact biological sensor based on two piezoelectric plates separated by an air gap was demonstrated on the example of amoxicillin and Escherichia coli for the first time. An acoustic wave with transverse horizontal polarization is excited in the bottom plate of the sensor. The upper plate serves as the bottom of the container with the studied cell suspension. It was shown that the addition of an antibiotic to the cell suspension leads to a change in the parameters of the sensor. The effect of amoxicillin on microbial cells was monitored by laser microscopy and standard microbiological culture. The possibility of express analysis of the drug’s antibacterial activity using a biological sensor based on the use of a slit acoustic wave is shown.

Antibiotics are widely used in medicine, veterinary medicine, and the food industry. However, the active use of antibacterial drugs leads to environmental pollution. In this regard, there is a great need for monitoring and determining antibiotics in various environments such as drinking water, food, drinks, waste water from pharmaceutical factories, etc. A number of methods, including those based on biosensors, have been developed to determine antibiotics. Biosensor methods of analysis are widely used and are an integral part of environmental monitoring. Electrochemical, optical, acoustic, microbial biosensors, immuno- and aptasensors, as well as sensors based on molecularly imprinted polymers are in the most demand for the analysis of antibiotics. This article provides a brief overview of biosensor methods and approaches for the determination of antibiotics. The most promising biosensor systems for determining antibacterial drugs were analyzed.

Антибиотики широко применяются в медицине, ветеринарии и пищевой промышленности. Однако активное использование антибактериальных препаратов приводит к загрязнению окружающей среды. В связи с этим существует большая потребность в мониторинге и определении антибиотиков в различных средах, таких как питьевая вода, продукты питания, напитки, сточные воды фармацевтических предприятий и др. Для определения антибиотиков разработано достаточное количество методов, в том числе и на основе биосенсоров. Биосенсорые методы анализа имеют довольно широкое применение и являются неотъемлемой частью при экологическом мониторинге. Наиболее востребованными для анализа антибиотиков являюся электрохимические, оптические, акустические, микробные биосенсоры, иммуно- и аптасенсоры, а также сенсоры на основе молекулярно-импринтированных полимеров. В статье приводится краткий обзор биосенсорных методов и подходов для определения антибиотиков. Проведен анализ наиболее перспективных биосенсорных систем при определении антибактериальных препаратов.

The study shows the possibility of rapid analysis of bacterial sensitivity to beta-lactam antibiotics on the example of ampi-clllln by using a piezoelectric resonator with a lateral electric field. It is established that the indicator of the sensitivity of microbial cells to the antibiotic and the criterion of its impact is the difference between the recorded sensor signal for cell suspension without the antibiotic and the sensor signal after the exposure to an antibiotic. The data obtained using the sensor confirmed the standard microbiological method for determining the sensitivity of microbial cells to ampicillin. The analysis of microbial cell sensitivity/resistance to ampicillin was carried out directly in the liquid phase without immobilizing the antibiotic on the surface of the piezoelectric. The advantages of this approach are high sensitivity of the method, measurement accuracy (within ± 2%) and short analysis time (within 10 minutes). The results show the benefits of using a piezoelectric resonator with a transverse electric field for analyzing the sensitivity/resistance of microbial cells to ampi-cillin.

A method been developed for the rapid determination of bacteria on the example of E. coli cells in tap water with a slot-mode sensor in the acoustic-delay line. The method is based on the recording of changes in the depth and frequency of the resonance-absorption peaks on the frequency dependence of the output signal of the sensor before and after the infection of microbial cells with specific bacteriophages. Control experiments excluding the nonspecific interaction of microbial cells with bacteriophages were carried out. The bacterial detection limit turned out to be ~103 cells/mL with an analysis time of 5 min. A distinctive feature of the used sensor is the presence of a removable liquid container. This allows its reuse and facilitates the process of eliminating the sample from the container.

A method has been developed for the rapid determination of bacteria with the help of an acoustic sensor using as example E. coli cells in water when they are infected with specific bacteriophages. The detection limit is ~ 10^3 cells/ml, with an analysis time of 5 min.