520
Volume 5, Issue 10: Special Issue
(EJAR)
ISSN: 2181-2020
MPHAPP
THE 6TH INTERNATIONAL SCIENTIFIC AND PRACTICAL
CONFERENCE
“
MODERN PHARMACEUTICS: ACTUAL
PROBLEMS AND PROSPECTS
”
TASHKENT, OCTOBER 17, 2025
in-academy.uz
STUDY OF THE COMBINED ACTIVITY OF POLYHEXAMETHYLENE
GUANIDINE HYDROCHLORIDE AND
TETRAMETHYLENEDIAMINETETRAMINE AGAINST CLINICAL ISOLATES
D.D. Kurlovich
R.V. Kravchenko
Vitebsk State Order of the Friendship of Peoples Medical University, Vitebsk, Republic of
Belarus
e-mail: xolelo2014@gmail.com, tel.: +375 29 815-41-90
https://doi.org/10.5281/zenodo.17343817
Background:
The widespread availability and use of antibacterial and antiseptic agents have
led to the emergence of antimicrobial resistance among many strains of pathogenic and conditionally
pathogenic microorganisms. Antibiotic resistance poses a particular challenge in the treatment of
nosocomial infections in hospital settings, especially in intensive care units (ICUs). Addressing the
pharmacotherapy of nosocomial infections in ICUs remains one of the most pressing issues in modern
medicine. To tackle this problem, novel antimicrobial agents as well as their combined activity are
being investigated. Synergistic interactions between antimicrobials can facilitate therapy and enhance
efficacy at lower doses, thereby reducing adverse and toxic effects on the human div.
Objective:
To evaluate the combined antimicrobial activity of two antiseptic agents against
clinical strains of Escherichia coli and Staphylococcus aureus using the checkerboard method.
Materials and Methods:
Six clinical isolates obtained from the Vitebsk Regional Clinical
Center were included in the study: E. coli (strains №778, №779, №809) and S. aureus (strains №767,
№765, №975). Additionally, reference strains from the American Type Culture Collection (ATCC)
were tested: E. coli ATCC №25922 and S. aureus ATCC №25923. The combined activity of two
antimicrobial agents—belonging to the classes of quaternary ammonium compounds (QACs) and
biguanides—was assessed.
Results:
Minimum inhibitory concentrations (MICs) of the individual compounds against the
reference strains (E. coli ATCC №25922 and S. aureus ATCC №25923) and the clinical isolates (E.
coli №778, №779, №809; S. aureus №767, №765, №975) had been previously determined. Based on
these data, the combined antimicrobial activity was evaluated in duplicate experiments.
The combination demonstrated synergistic activity against the reference strain E. coli ATCC
№25922. Neutral (indifferent) interactions were observed for the clinical isolates E. coli №778, S.
aureus №767, and S. aureus №975. Additive effects were found for E. coli №779 and №809, S. aureus
№765, and S. aureus ATCC №25923. Notably, against certain multidrug-resistant isolates, the
combination exhibited additive or synergistic activity, highlighting its potential for the
pharmaceutical development of topical antimicrobial formulations.
Conclusions:
The observed synergistic and additive interactions enable the use of lower
concentrations of each active substance compared to monotherapy. Reduced concentrations may
decrease the incidence of adverse effects and slow the development of microbial resistance, thereby
significantly improving the management of multidrug-resistant microorganisms.
