Analytical devices for bacterial detection are an integral part of modern laboratory medicine, as they permit the early diagnosis of diseases and their timely treatment. Therefore, special attention is directed to the development of and improvements in monitoring and diagnostic methods, including biosensor-based ones. A promising direction in the development of bacterial detection methods is optical sensor systems based on colorimetric and fluorescence techniques, the surface plasmon resonance, and the measurement of orientational effects. This review shows the detecting capabilities of these systems and the promise of electro-optical analysis for bacterial detection. It also discusses the advantages and disadvantages of optical sensor systems and the prospects for their further improvement.

Infection diagnosis and antibiotic sensitivity testing are important aspects of clinical microbiology that are in dire need of improvement owing to the inadequate current standards in the early detection of bacterial response to antibiotics. The increasing antimicrobial resistance is a serious global threat to human health. Current resistance-detecting methods, using the phenotypic antibiotic sensitivity test, which measures bacterial growth as affected by antibiotics, have long analysis times. Therefore, new and rapid methods are needed to detect antibiotic resistance. Here, we review the methods used to detect antibiotic resistance in bacteria, including that caused by biofilm development, and we look at the development of rapid methods for evaluating antimicrobial resistance (AMR).

In this study, a compact acoustic analyzer for express analysis of antibiotics based on a piezoelectric resonator with a lateral electric field and combined with a computer was developed. The possibility of determining chloramphenicol in aqueous solutions in the concentration range of 0.5–15 μg/mL was shown. Bacterial cells that are sensitive to this antibiotic were used as a sensory element. The change in the electrical impedance modulus of the resonator upon addition of the antibiotic to the cell suspension served as an analytical signal. The analysis time did not exceed 4 min. The correlation of the experimental results of an acoustic sensor with the results obtained using the light phase-contrast microscopy and standard microbiological analysis was established. The compact biological analyzer demonstrated stability, reproducibility, and repeatability of results.

Excessive and sometimes inappropriate use of antibiotics leads to the emergence of multidrug-resistant (MDR) strains. Antibiotic-resistant pathogens are a major public health problem in routine clinical practice and have severe economic consequences due to increased treatment costs. Timely testing of antimicrobial susceptibility for bacterial infections ensures accurate prescribing, reduces treatment time, and helps minimize the spread of antibiotic-resistant infections. The main problem with antibiotic susceptibility testing is that there are not enough fast diagnostic tests to allow appropriateantibiotic prescribing at the point of care. Using traditional methods, determining the sensitivity of bacteria to antibiotics requires a minimum of 24 hours. Therefore, the development of express methods for determining antibacterial resistance, especially using biosensor systems, is relevant. The work provides a brief analysis of the problems of antibiotic sensitivity of bacteria in the world and presents the main mechanisms of its development, as well as describes the prospects of sensor methods for assessing the antibiotic resistance of bacteria.

Large-scale production and use of antimicrobials in human, veterinary and agricultural applications has led to antibiotic contamination of water resources. Therefore, it is relevant to develop methods for monitoring the content of antibiotics, especially in water resources. Biosensor methods are successful for the analysis of antibiotics. One of the main elements of a biosensor system is the selection of a recognition element. An alternative tool for selecting a sensitive element (recognition element) is phage display of antibodies, which makes it possible to obtain antibodies to low molecular weight antigens. The purpose of the work was to conduct research to develop and optimize the methodology for obtaining antibodies specific to tetracycline by using phage display technology, and to evaluate the possibility of their use for the indication of tetracycline. The work included studies of optimization of conditions for the production of phage antibodies specific to tetracycline, as well as the preservation of their activity during storage. The promise of using phage display technology for the production of anti-tetracycline antibodies has been shown. Using the dot immunoassay method, the possibility of using the obtained phage antibodies for tetracycline detection was shown.

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.