Tannic Acid-Stabilized Silver Nanoparticles Used in Biomedical Application as an Effective Antimelioidosis and Prolonged Efflux Pump Inhibitor against Melioidosis Causative Pathogen

Abstract

Burkholderia pseudomallei is the causative pathogen of melioidosis and this bacterium is resistant to several antibiotics. Silver nanoparticles (AgNPs) are an interesting agent to develop to solve this bacterial resistance. Here, we characterize and assess the antimelioidosis activity of AgNPs against these pathogenic bacteria. AgNPs were characterized and displayed a maximum absorption band at 420 nm with a spherical shape, being well-monodispersed and having high stability in solution. The average size of AgNPs is 7.99 ± 1.46 nm. The antibacterial efficacy of AgNPs was evaluated by broth microdilution. The bactericidal effect of AgNPs was further assessed by time-kill kinetics assay. Moreover, the effect of AgNPs on the inhibition of the established biofilm was investigated by the crystal violet method. In parallel, a study of the resistance induction development of B. pseudomallei towards AgNPs with efflux pump inhibiting effect was performed. We first found that AgNPs had strong antibacterial activity against both susceptible and ceftazidime-resistant (CAZ-resistant) strains, as well as being efficiently active against B. pseudomallei CAZ-resistant strains with a fast-killing mode via a bactericidal effect within 30 min. These AgNPs did not only kill planktonic bacteria in broth conditions, but also in established biofilm. Our findings first documented that the resistance development was not induced in B. pseudomallei toward AgNPs in the 30th passage. We found that AgNPs still showed an effective efflux pump inhibiting effect against these bacteria after prolonged exposure to AgNPs at sublethal concentrations. Thus, AgNPs have valuable properties for being a potent antimicrobial agent to solve the antibiotic resistance problem in pathogens.

Characterization and Rate of Killing of Conjugated Silver Nanoparticles Against Selected Clinical Bacterial Isolates

“…The results obtained for the rate of killing by the CAgNPs showed reductions in the populations of all the clinical bacterial isolates: E. coli strain MRE 600 (CP014197.1), Salmonella enteric subsp. Enteric serovar typhi PMO 16/13 (CP12091.1), K. pneumoniae strain HZW25 (CP025211.1) and P. fluorescens strain 2P24 (CP025542.1) between the periods of 1-7 h. These results were similar to the ones obtained in the studies of Betts et al (2018); Smirnova and Oktyabrsky (2018); Srichaiyapol et al (2021), in which there was a reduction in the population of the bacteria as the time of exposure increased. The value of 0.00log 10 cfu/ml was obtained at the sixth and seventh hours when E. coli strain MRE 600 (CP014197.1) was exposed to the CAgNPs, possibly showing the most significant bactericidal effect on E. coli strain MRE 600 (CP014197.1) followed by Salmonella enteric subsp.…”

“…In addition, the TEM result (Figure 3) revealed that the CAgNPs are spherical in shapes that facilitate the delivery of drugs to the target sites, as reported in the studies of Govindaraju et al (2010); Saeed et al (2020). The presence of silver as revealed by the EDS spectrum (Figure 3) in the characterized CAgNPs is similar to the results obtained by Samuggam et al (2021); Srichaiyapol et al (2021), in which silver was also present.…”

AgNPs Targeting the Drug Resistance Problem of Staphylococcus aureus: Susceptibility to Antibiotics and Efflux Effect

“…The first mention of AgNPs as EPIs we found in a 2018 publication, in which obtained results only provided circumstantial (not direct) evidence indicative of AgNPs functioning as EPIs [12]. For the last three years, the articles published results of in vitro experiments showing that AgNPs can decrease the efflux pump gene expression, reduce expression of functional efflux pump proteins, inhibit activity of P-glycoprotein (Pgp, the drug transporters that determine the uptake and efflux of drugs), or change efflux pump activity [12][13][14][15][16][17][18][19][20][21][22]. These results were obtained with application of AgNPs alone or in combination with antibiotics or other drugs, to which microorganisms or cells had already developed resistance.…”

“…These results were obtained with application of AgNPs alone or in combination with antibiotics or other drugs, to which microorganisms or cells had already developed resistance. These publications include influence of AgNPs on the efflux effect of P. aeruginosa [13][14][15], Escherichia coli [17][18][19], A. baumannii [14][15][16], K. pneumonia [20,21], Burkholderia pseudomallei [22], E. cloacae [12]. Moreover, the influence of AgNPs on the efflux effect was studied on Bifidobacterium bifidum probiotic, the drug-resistant cancer MCF-7/KCR cell line [23], and planktonic cells and biofilms [24].…”

Recent advances in nanoantibiotics against multidrug-resistant bacteria

“…3C). 120 In summary, bacteria have evolved various resistance mechanisms against antibiotics. How to rebuild the sensitivity of drug-resistant bacteria to the present antibiotics or nd alternatives to synthetic antibiotics to combat bacteria is a big challenge to human beings.…”