V.B. Bayburin1, V.M. Doroshenko2, A.A. Nikiforov3, Yu.V. Fadeeva4, Z.R. Zenchenko5, A.A. Shirokov6, L.Yu. Matora7, V.A. Kirkitsa8

1,2,3,8 Yuri Gagarin Saratov State Technical University (Saratov, Russia)
4,5,6,7 Institute of Biochemistry and Physiology of Plants and Microorganisms – a separate structural division of the Federal State Budgetary Scientific Institution, the Federal Research Center "Saratov Scientific Center of the Russian Academy of Sciences" (Saratov, Russia)
1 baiburinvb@rambler.ru; 2 dorvalentina9@gmail.com; 3 ieei_director@mail.ru; 4 fadeeva-yuv@yandex.ru; 5 zenchenko@mail.ru; 6 shirokov_a@ibppm.ru; 7 matora_l@ibppm.ru; 8 SKrkts@mail.ru

The mechanisms by which microwave radiation influences pathogenic microflora are currently not fully understood. To understand population dynamics and the response to microwave treatment, it is necessary to develop a method for assessing bacterial viability on contaminated metal instrument surfaces. This will allow for a step-by-step monitoring of cell population dynamics and the determination of optimal parameters for achieving complete decontamination.

The aim of this experimental study is to analyze microorganism viability after each sterilization mode using flow cytometry, assess the ratio of live, dead, and damaged bacterial cell subpopulations of the Escherichia coli strain, and determine the optimal treatment parameters for complete instrument sterilization.

This paper presents the experimental results of a flow cytometric analysis of the viability of bacterial suspensions after microwave sterilization of medical instruments contaminated with the Escherichia coli strain under various time regimens and at a single power level. The optimal parameters for complete instrument sterilization are determined. The study utilized the Escherichia coli K-12 (IBPPM 204) microbial strain provided by the Rhizospheric Microorganism Collection at the Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences. The experimental results will be used in the final development of microwave sterilizers capable of effectively decontaminating pathogenic microflora during sterilization of medical instruments under a wide range of conditions.

1. Bajburin V.B., Meshchanov V.P., Komarov V.V., Luneva I.O., Doroshenko V.M., Sayapin K.A., Kirkica V.A. Problemy bystroj SVCh‑sterilizacii metallicheskih instrumentov medicinskogo naznacheniya. Biomedicinskaya radioelektronika. 2025. № 1. S. 76–82 (In Russian).
2. Bajburin V.B., Balakin M.I., Komarov V.V., Luneva I.O., Nikiforov A.A., Meshchanov V.P. Bystryj metod polnoj dekontaminacii v SVCH elektromagnitnom pole. Voprosy elektrotekhnologii. 2022. № 2(35). S. 27–30 (In Russian).
3. Bajburin V.B., Meshchanov V.P., Luneva I.O., Komarov V.V., Nikiforov A.A., Fomin A.A., Doroshenko V.M., Balakin M.I., Kirkica V.A. Eksperimental'nye rezul'taty SVCh‑sterilizacii metallicheskih instrumentov medicinskogo naznacheniya. Biomedicinskaya radioelektronika. 2023. № 6. S. 77–82 (In Russian).
4. Berney M., Hammes F., Bosshard F., Weilenmann H.U., Egli T. Assessment and interpretation of bacterial viability by using the LIVE/DEAD BacLight Kit in combination with flow cytometry. Applied and Environmental Microbiology. 2007. V. 73. № 10. P. 3283–3290. DOI: 10.1128/AEM.02750-06.
5. Davey H.M. Life, death, and in‑between: meanings and methods in microbiology. Applied and Environmental Microbiology. 2011. V. 77. № 16. P. 5571–5576. DOI: 10.1128/AEM.00744-11.
6. McDonnell G., Burke P. The challenge of prion decontamination. Clinical Infectious Diseases. 2003. V. 36. № 9. P. 1152–1154. DOI: 10.1086/374668.
7. Nebe‑von‑Caron G., Stephens P.J., Hewitt C.J., Powell J.R., Badley R.A. Analysis of bacterial function by multi‑colour fluorescence flow cytometry and single cell sorting. Journal of Microbiological Methods. 2000. V. 42. № 1. P. 97–114. DOI: 10.1016/s0167-7012(00)00181-0.
8. Ponne C.T., Bartels P.V. Interaction of electromagnetic energy with biological material relation to food processing. Radiation Physics and Chemistry. 1996. V. 45, Is. 4. P. 591–607. DOI: 10.1016/0969-806X(94)00073-S.
9. Robertson J. Overview of Flow Cytometry and Microbiology. Cytometry Part A of Current Protocols. 2019.
10. Rutala W.A., Weber D.J. Disinfection and Sterilization in Health Care Facilities: An Overview and Current Issues. Infectious Disease Clinics of North America. 2016. V. 30. № 3. P. 609–637. DOI: 10.1016/j.idc.2016.04.002.
11. Sambrook J. Molecular Cloning: A Laboratory Manual. 2nd ed. Cold Spring Harbor: Cold Spring Harbor Laboratory Press. 1989.
12. Shamis Y., Croft R., Taube A., Crawford R.J., Ivanova E.P. Review of the specific effects of microwave radiation on bacterial cells. Applied Microbiology and Biotechnology. 2012. V. 96. № 2. P. 319–325. DOI: 10.1007/s00253-012-4339-y.
13. Shamis Y., Taube A., Mitik‑Dineva N., Croft R., Crawford R.J., Ivanova E.P. Specific Electromagnetic Effects of Microwave Radiation on Escherichia coli. Applied and Environmental Microbiology. 2011. V. 77.