Approximate method for microorganisms' sensitivity determination to complex antibacterial drugs

DOI 10.33861/2071-8020-2021-2-34-36

Avduevskya N.N., Semina L.K., Skulyabina Z.A.

Summary. Analysis of the results of microbiological studies of milk (udder secretions) from farms in the Vologda, Yaroslavl and Kostroma regions showed that in 2020, pathogenic and opportunistic flora in the spectrum of isolated microflora was 85 cultures (31.6%), lactic acid and other non-pathogenic - 131 cultures (48.7%). In the study of antibiotic sensitivity, pure cultures of microorganisms were used: 11 strains of Staphylococcus aureus, 6 strains of opportunistic staphylococci, 6 strains of enterobacteria and 4 strains of agalactic Streptococcus were isolated from cow udder secretions. 36 intravenous syringes containing one or two or more antibiotics were used as complex antimicrobials. The sensitivity of the above-mentioned microorganisms to antibacterial drugs was determined by the disco-diffusion method. In the case of the study, method does not allow authors to evaluate the result according to the criteria for standard disks and is indicative in choosing a particular drug for the treatment of cows with mastitis. In the course of the work, authors determined the average zone of growth retardation of Staphylococcus aureus on the example of seven farms and their frequently used complex antibacterial drugs. The obtained results indicate significant fluctuations in the size of zones of growth retardation of pathogenic Staphylococcus both for complex preparations and for farms. In this regard, determining the sensitivity of the isolated microorganism (pathogenic or opportunistic) to complex antibacterial drugs is relevant and significant for practicing veterinary specialists. In accordance with the research, authors have proposed an approximate method for determining the sensitivity of microorganisms isolated from the milk of cows with mastitis to complex antimicrobial drugs in the form of suspensions and solutions. The proposed method allows veterinary doctors of farms to decide on the choice of a particular drug for the treatment of cows during lactation and prevention of mastitis during dead wood with the greatest effectiveness.

Keywords: large horned cattle, lactation, cow mastitis, treatment, microorganisms, sensitivity, antibiotic resistance, complex antimicrobial agents, solution, suspension, disco-diffusion method.

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Author affiliation:

Semina Lyudmila K., Ph.D. in Veterinary Medicine, Leading Scientific Researcher of the Vologda Branch of the Federal Scientific Center - All-Russian Scientific Research Institute of Experimental Veterinary Medicine named after K.I. Skryabin and Ya.R. Kovalenko of the Russian Academy of Sciences; 10, Chekhova st., Vologda, 160009; e-mail: viev-mastit@yandex.ru.

Skulyabina Zoya A., Senior Scientific Researcher of the Vologda Branch of the Federal Scientific Center - All-Russian Scientific Research Institute of Experimental Veterinary Medicine named after K.I. Skryabin and Ya.R. Kovalenko of the Russian Academy of Sciences; 10, Chekhova st., Vologda, 160009; e-mail: zengira@mail.ru.

Responsible for correspondence with the editorial board: Avduevskaya Natalya N., graduate student, Scientific Researcher of the Vologda Branch of the Federal Scientific Center - All-Russian Scientific Research Institute of Experimental Veterinary Medicine named after K.I. Skryabin and Ya.R. Kovalenko of the Russian Academy of Sciences; 10, Chekhova st., Vologda, 160009; e-mail: natali.avduevskaya@mail.ru.