Antimicrobial and Antifungal Action of Biogenic Silver Nanoparticles in Combination with Antibiotics and Fungicides Against Opportunistic Bacteria and Yeast

Abstract

The development of multidrug resistance by pathogenic bacteria and yeast is a significant medical problem that needs to be addressed. One possible answer could be the combined use of antibiotics and silver nanoparticles, which have different mechanisms of antimicrobial action. In the same way, these nanoparticles can be combined with antifungal agents. Biogenic silver nanoparticles synthesized using environmentally friendly biosynthesis technology using extracts of biologically active plants are an effective nanomaterial that needs to be comprehensively investigated for implementation into medical practice. In this study, the synergistic effects arising from their combined use with antibiotics and fungicides against various bacteria and yeasts were studied. The following methods were used: disco-diffusion analysis and construction of plankton culture growth curves. The synergistic effect of silver nanoparticles and antibiotics (fungicides) has been determined. Effective concentrations of substances were established, recommendations for the studied pathogenic species were presented, and the effect of destruction of the bacterial membrane was illustrated. The most significant synergistic effect was manifested in pathogenic candida and brewer's yeast.

Keywords: Alcanivorax borkumensis; Candida; Pseudomonas putida; antibiotic; antifungal action; antimicrobial action; biogenic silver nanoparticles; fungicide.

Figure 1

The results of replication of silver nanoparticles (of different concentrations) and sphagnum extract on the formation of biofilms of S. marcescens (1) and P. putida (2).

Figure 2

Determination of the antibacterial activity of biogenic silver nanoparticles and sphagnum extract against S. aureus and E. coli by the method of constructing growth curves. The concentrations of nanoparticles are given in the captions.

Figure 3

Determination of the antibacterial activity of biogenic silver nanoparticles and sphagnum extract against S. marcescens and C. albicans by constructing growth curves. The concentrations of nanoparticles are given in the captions.

Figure 4

Visualization of the results of disco diffusion analysis of inhibition of 5 bacterial species by 6 antibiotics. 1—streptomycin, 2—tetracycline, 3—ceftriaxone, 5—ciprofloxacin, 6—erythromycin, 7—amoxicillin, K—control.

Figure 5

Visualization of the results of the disco-diffusion analysis of the effect of three fungicides on three types of yeast. M—copper sulfate, MM—10-fold copper sulfate, X—chloramine, XX—10-fold chloramine, Δ—desgrane, Δ Δ—10-fold desgrane, K—control.

Figure 6

Growth curves of P. putida and A. borkumensis cultivated in the presence of the antibiotic (ciprofloxacin or ceftriaxone) and silver nanoparticles.

Figure 7

Growth curves of E. coli, S. marcescens, and S. aureus cultivated in the presence of the antibiotic (ciprofloxacin or amoxicillin) and silver nanoparticles.

Figure 8

Growth curves of C. albicans, C. lipolytica, and S. cerevisiae cultivated in the presence of tetramethylenediethylenetetramine and silver nanoparticles.

Figure 9

Images of S. marcescens biofilms obtained by atomic force microscopy cultured in the presence of silver and ciprofloxacin nanoparticles. 1—control sample, 2—biogenic silver nanoparticles, 3—chemically synthesized silver nanoparticles, 4—antibiotic, 5—biogenic silver nanoparticles with the addition of an antibiotic, and 6—chemically synthesized silver nanoparticles with the addition of an antibiotic.

Figure 10

Images of the general appearance and surface of E. coli cells cultured in the presence of silver nanoparticles and sphagnum extract were obtained using atomic force microscopy. 1, 4—control sample, 2, 5—silver nanoparticles, 3, 6—sphagnum extract.

Figure 11

Images of the general appearance and surface of S. marcescens cells cultured in the presence of silver nanoparticles and sphagnum extract were obtained using atomic force microscopy. 1, 4—control sample, 2, 5—silver nanoparticles, 3, 6—sphagnum extract.

Figure 12

Changes in the color of the reaction mixture of moss extract and silver nitrate, from transparent at the beginning of synthesis (A) to yellow-brown after 7 days (B).

Figure 13

Absorption spectra in the UV-visible range of nanoparticle suspensions: biogenic silver nanoparticles (a); sphagnum extract (b).

Figure 14

Visualization of AgNPs using transmission electron microscopy—(A). The shape of the particles is irregularly spherical. Elemental analysis of silver nanoparticles using transmission electron microscopy—(B).

Figure 15

Microscopic photographs of planktonic yeast forms from fresh nocturnal cultures. Bright field microscopy.