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Metabolite-aminoglycoside killing is specific to aminoglycoside antibiotics, requires PMF, and does not require cell growth. a, Survival of stationary-phase E. coli (grey), S. typhimurium (blue), and K. pneumoniae (green) cells after treatment with gentamicin (10 μg/mL), gentamicin plus mannitol (10 mM), norfloxacin (5 μg/mL), norfloxacin plus mannitol, ampicillin (100 μg/mL), ampicillin plus mannitol, and gentamicin plus mannitol and CCCP (2.5 μg/mL). b, Growth of stationary-phase E. coli cultures after addition of 10 mM of the following metabolites: mannitol, glucose, fructose, and sorbitol. Plots represent mean +/-standard deviation for three or more replicates. c, Illustrative examples of stationary-phase E. coli cells (~400 observed) containing constitutively-expressed scarlet (red) and inducible GFP (green) tracked by microscopy at 37˚C after addition of 20 nM anhydrotetracycline and 10 mM mannitol (top) or no metabolite (bottom). Scale bar represents 6 μm. d, Illustrative examples of rare "cheater" cells (~3%) from the same experiments.
Source publication
The lack of new antibiotics necessitates the improvement of existing ones, many of which are limited by toxic side effects. Aminoglycosides, antibiotics with excellent activity and low bacterial resistance, are hampered by dose-dependent toxic effects in patients (nephrotoxicity, ototoxicity). High antibiotic concentrations are often required to tr...
Contexts in source publication
Context 1
... studies uncovered the importance of proton-motive force (PMF) in potentiating aminoglycoside against E. coli [6,49] and have indicated that metabolites do not return cells to active growth given that other classes of antibiotics are not potentiated [6,49]. We sought to test the specificity of potentiation in these Gram-negative species and treated each with norfloxacin or ampicillin in presence of metabolite (Fig 4A). Neither norfloxacin nor ampicillin were potentiated by mannitol in any species tested, suggesting that the processes of cell-wall synthesis and DNA replication targeted by these antibiotics remained inactive. ...
Context 2
... norfloxacin nor ampicillin were potentiated by mannitol in any species tested, suggesting that the processes of cell-wall synthesis and DNA replication targeted by these antibiotics remained inactive. Additionally, using carbonyl cyanide m-chlorophenyl hydrazone (CCCP), we showed that PMF was a requirement for potentiation in these species (Fig 4A), as was seen in E. coli persisters previously [6,49]. ...
Context 3
... of the inactivity of norfloxacin and ampicillin, we investigated if any of the metabolites used stimulated cellular growth over longer time scales. Similar to potentiation experiments, metabolites were added to stationary phase cultures, but no antibiotic was added and colony forming data was collected over an 8 hours rather than 2 hours (Fig 4B). We found that little-to-no growth was induced by any metabolite during this time frame, though all could serve as carbon sources if cultures were diluted in minimal media with extended growth periods. ...
Context 4
... to simultaneously observe division and nascent protein synthesis resulting from metabolite supplementation. Dynamically tracking ~400 cells, we found that mannitol supplementation did not cause significant cell division (Fig 4C). Cells in both mannitol (+) and mannitol (-) conditions remained non-dividing for up to 12 hours, supporting the bulk-culture data ( Fig 4B). ...
Context 5
... tracking ~400 cells, we found that mannitol supplementation did not cause significant cell division (Fig 4C). Cells in both mannitol (+) and mannitol (-) conditions remained non-dividing for up to 12 hours, supporting the bulk-culture data ( Fig 4B). Intriguingly, new protein synthesis was observed to a similar degree in both mannitol (+) and mannitol (-) samples. ...
Context 6
... growth heterogeneity was observed in the late stages of these experiments: rare cells (~3%) in both mannitol (+) and mannitol (-) conditions began dividing around 8 hours and had formed microcolonies by 12 hours (Fig 4D). This is not due to heterogeneous availability of nutrients as dividing cells are present in them same environment as, and with little distance from, non-dividing cells. ...
Context 7
... behavior of these cells further indicates that the population majority is not arrested because of a lack of nutrients (also supported by the small difference between mannitol (+) and mannitol (-)), and instead may be stuck at a growth-phase checkpoint. In light of the observed translation (Fig 4C), these findings (Fig 4D) suggest that stationary-phase cells actively maintain a growth-arrested state. ...
Context 8
... behavior of these cells further indicates that the population majority is not arrested because of a lack of nutrients (also supported by the small difference between mannitol (+) and mannitol (-)), and instead may be stuck at a growth-phase checkpoint. In light of the observed translation (Fig 4C), these findings (Fig 4D) suggest that stationary-phase cells actively maintain a growth-arrested state. ...
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... further showed that it could improve treatment of biofilms (Fig 2) and did not contribute to increasing aminoglycoside resistance (Fig 3). Through investigating the physiological role of metabolites in potentiation, we uncovered evidence that stationary-phase cells, while non-dividing, have active protein synthesis and appear to maintain a dormant state that is not necessarily reversed by added nutrients (Fig 4). Additionally, we have demonstrated that mannitol, in addition to reducing the necessary aminoglycoside concentration to achieve high bacterial killing, may also protect against aminoglycoside cytotoxicity in human kidney cells (Fig 5). ...
Citations
... High concentrations of these antibiotics are often required to treat quiescent and non-developing bacteria, although previous studies have shown that aminoglycosides can be activated against such bacteria by specific metabolites. Mannitol could directly protect human kidney cells from the cytotoxicity of aminoglycosides [210]. Inhibit NMD and restore full-length p53 [59,177] 5-Fluorouracil Different action [197] Y-320 Different action [198] CX-5461 Activate p53 [208] ...
... Hence, repressing rpoS by disrupting rosette formation (Fig. 4) would likely reduce antibiotic tolerance. This warrants further investigation, but, if effective, rosette disruption could then be used to enhance recently discovered antibiotics (94)(95)(96) or mechanism-based improvement of existing antibiotics (97,98), like metabolic potentiation of aminoglycosides (99)(100)(101)(102). ...
Rosettes are self-organizing, circular multicellular communities that initiate developmental processes, like organogenesis and embryogenesis, in complex organisms. Their formation results from the active repositioning of adhered sister cells and is thought to distinguish multicellular organisms from unicellular ones. Though common in eukaryotes, this multicellular behavior has not been reported in bacteria. In this study, we found that Escherichia coli forms rosettes by active sister-cell repositioning. After division, sister cells “fold” to actively align at the 2- and 4-cell stages of clonal division, thereby producing rosettes with characteristic quatrefoil configuration. Analysis revealed that folding follows an angular random walk, composed of ~1 µm strokes and directional randomization. We further showed that this motion was produced by the flagellum, the extracellular tail whose rotation generates swimming motility. Rosette formation was found to require de novo flagella synthesis suggesting it must balance the opposing forces of Ag43 adhesion and flagellar propulsion. We went on to show that proper rosette formation was required for subsequent morphogenesis of multicellular chains, rpoS gene expression, and formation of hydrostatic clonal-chain biofilms. Moreover, we found self-folding rosette-like communities in the standard motility assay, indicating that this behavior may be a general response to hydrostatic environments in E. coli . These findings establish self-organization of clonal rosettes by a prokaryote and have implications for evolutionary biology, synthetic biology, and medical microbiology.
... Связываясь с рибосомной РНК в А-сайте 80S-субъединицы, аминогликозиды снижают специфичность декодирования и делают возможным добавление к полипептидной цепочке аминокислоты в позиции стоп-кодона [12,13]. Ограничения использования аминогликозидов связаны со специфичностью в отношении стоп-кодонов и их достаточно высокой токсичностью (особенно нефро-и ототоксическими эффектами [14,15]). Для гентамицина, например, показано преимущественное прохождение кодона TGA, но не TAA и TAG [16]. ...
Duchenne muscular dystrophy is one of the most common inherited muscular dystrophies. The cause of this disease with an X‑linked recessive type of inheritance is mutations in the DMD gene, leading to the absence of the dystrophin protein this gene encodes or its impaired function. Loss of dystrophin leads to severe degenerative processes in patients, especially in muscle tissue, with impaired muscle function, loss of ability to move independently, respiratory failure, cardiomyopathies, etc.
The collective efforts of many researchers over the years since the 19 th century, when the diseases was described, not allowed to achieve a cure or significantly influencing the trajectory of the illness. The only notable impact on the disease course has come with the integration of corticosteroid medications into Duchenne muscular dystrophy therapy. While their application can decelerate disease progression and extend the average life expectancy up to 30–40 years, it comes with substantial adversely affects influencing patients’ quality of life.
Certain hopes were associated in recent decades with the development of etiotropic therapy for Duchenne muscular dystrophy, aimed at restoration of the dystrophin’s function. Some of such approaches were based on the overcoming of the effect of premature stop codons in the DMD gene using aminoglycoside antibiotics, ataluren, etc. Several subsequent studies were conducted to explore the applicability of exon‑skipping approaches in the dystrophin gene, aimed at excluding exons carrying pathogenic genetic variants. The rationale for these studies was the available information about a milder course of the disease associated with a truncated but functional dystrophin. The possibility of the pathology correction by means of introduction of the exogenous functional DMD gene copy from the outside (gene replacement therapy) has been under study since the beginning of the 20 th century. One of the most promising directions in recent years was the development of approaches related to genome editing, which, unlike the methods mentioned above, allows for the permanent correction of the underlying cause of genetic diseases. Some of corresponding drugs have already received approval, while others, related to gene therapy, are at the stage of clinical trials.
... The stem fractions generally showed weak activity against GNB biofilms but had significant activity against both S. aureus and M. smegmatis at higher concentrations (4MIC and 2MIC). The use of stem fractions to inhibit mature biofilms carries the risk of toxic side effects as higher concentrations increase the chances of toxicity and adverse effects when ingested [55]. The use of these stem fractions may be relevant to topical application against M. smegmatis and S. aureus infections involving the skin and wounds. ...
The formation of biofilms underscores the challenge of treating bacterial infections. The study aimed to assess the antioxidant, cytotoxicity, antibacterial, anti-motility, and anti-biofilm effects of defatted fractions from Myrothamnus flabellifolius (resurrection plant). Antioxidant activity was assessed using DPPH radical scavenging and hydrogen peroxide assays. Cytotoxicity was screened using a brine shrimp lethality assay. Antibacterial activity was determined using the micro-dilution and growth curve assays. Antibiofilm potential was screened using the crystal violet and tetrazolium reduction assay. Liquid–liquid extraction of crude extracts concentrated polyphenols in the ethyl acetate and n-butanol fractions. Subsequently, these fractions had notable antioxidant activity and demonstrated broad-spectrum antibacterial activity against selected Gram-negative and Gram-positive bacteria and Mycobacterium smegmatis (MIC values < 630 μg/mL). Growth curves showed that the bacteriostatic inhibition by the ethyl acetate fractions was through the extension of the lag phase and/or suppression of the growth rate. The sub-inhibitory concentrations of the ethyl acetate fractions inhibited the swarming motility of Pseudomonas aeruginosa and Klebsiella pneumoniae by 100% and eradicated more than 50% of P. aeruginosa biofilm biomass. The polyphenolic content of M. flabellifolius plays an important role in its antibacterial, anti-motility, and antibiofilm activity, thus offering an additional strategy to treat biofilm-associated infections.
... Current US guidelines, published in 2001, recommend streptomycin or gentamicin as the preferred treatment for adults, children, and pregnant women in a contained casualty setting [3]. However, aminoglycosides such as streptomycin and gentamicin are only available as intravenous or intramuscular formulations and can result in irreversible nephrotoxicity and ototoxicity, thus limiting their use for some patients [16]. Doxycycline and ciprofloxacin are recommended as alternatives during a contained casualty response, or as preferred antimicrobials for a mass casualty response or postexposure prophylaxis [3]. ...
Background
Francisella tularensis, the causative agent of tularemia, is endemic throughout the Northern Hemisphere and requires as few as 10 organisms to cause disease, making this potential bioterrorism agent one of the most infectious bacterial pathogens known. Aminoglycosides, tetracyclines, and, more recently, fluoroquinolones are used for treatment of tularemia; however, data on the relative effectiveness of these and other antimicrobial classes are limited.
Methods
Nine databases, including Medline, Global Health, and Embase, were systematically searched for articles containing terms related to tularemia. Articles with case-level data on tularemia diagnosis, antimicrobial treatment, and patient outcome were included. Patient demographics, clinical findings, antimicrobial administration, and outcome (eg, intubation, fatality) were abstracted using a standardized form.
Results
Of the 8878 publications identified and screened, 410 articles describing 870 cases from 1993 to 2023 met inclusion criteria. Cases were reported from 35 countries; more than half were from the United States, Turkey, or Spain. The most common clinical forms were ulceroglandular, oropharyngeal, glandular, and pneumonic disease. Among patients treated with aminoglycosides (n = 452 [52%]), fluoroquinolones (n = 339 [39%]), or tetracyclines (n = 419 [48%]), the fatality rate was 0.7%, 0.9%, and 1.2%, respectively. Patients with pneumonic disease who received ciprofloxacin had no fatalities and the lowest rates of thoracentesis/pleural effusion drainage and intubation compared to those who received aminoglycosides and tetracyclines.
Conclusions
Aminoglycosides, fluoroquinolones, and tetracyclines are effective antimicrobials for treatment of tularemia, regardless of clinical manifestation. For pneumonic disease specifically, ciprofloxacin may have slight advantages compared to other antimicrobials.
... Higher efcacy has been recorded in such studies compared to monotherapy where emergence of resistance to a single drug is more likely to occur [13]. Reports of combination of aminoglycosides with other antibiotics or plant-derived compounds have shown enhanced bactericidal activity against Salmonella enterica [14][15][16]. Also, synergistic activity has been recorded for some of the frst-line anti-Salmonella antibiotics (ampicillin, chloramphenicol, and cefotaxime) in combination with an aminoglycoside (gentamycin) against MDR Staphylococcus aureus [17]. ...
The global burden of Salmonella infections remains high due to the emergence of multidrug resistance to all recommended treatment antibiotics. Tetrahydroisoquinolines (THIQs) have demonstrated promising activity against multidrug-resistant (MDR) Salmonella Typhi. Hence, their interaction with treatment antibiotics was investigated for possible synergy. Twenty combinations of five THIQs (1, 2, 3, 4, and 5) and four antibiotics were tested against each of 7 Salmonella isolates by the checkerboard method giving a total of 140 assays performed. Fractional inhibitory concentration indices (FICIs) were calculated, and isobolograms were plotted. In terms of FICI, synergism ranged from 0.078 to 0.5 and the highest magnitude (0.078) was recorded for chloramphenicol-THIQ 1 combination. In a total of 140 antibiotics-THIQs combination assays, 27 were synergistic (17%), 42 were additive (30%), 11 were antagonistic (7.8%), and 60 were indifferent (42%). The synergistic activity recorded for each antibiotic class in combination based on the total of 7 bacterial isolates tested ranged from 14.29% to 71.43%; the highest percentage was recorded for two combinations (chloramphenicol or sulphamethoxazole with THIQ 1). Ciprofloxacin-THIQ 1 combination showed additivity on all bacteria isolates tested (100%). Overall, THIQ 1 was the most synergistic and most additive in combination with three antibiotics (ampicillin, chloramphenicol, or sulphamethoxazole-trimethoprim). Some combinations of the THIQs and treatment antibiotics have shown high synergism which could potentially be efficacious against multidrug-resistant S. Typhi, hence this interaction should be further studied in vivo.
... Adjuvants are compounds that typically have little to no inherent antibacterial activity, but instead enhance the activity of an antibiotic. Adjuvants can be employed to render resistant bacterial strains susceptible to an antibiotic [12], or to further enhance activity against a susceptible strain, thereby enabling lower antibiotic dosing which has the potential to reduce dose-dependent toxicity [13][14][15]. To identify new classes of adjuvants, our group has investigated analogs of sponge-derived marine alkaloids containing a 2-aminoimidazole (2-AI) heterocycle and has demonstrated that properly derivatized 2-AIs potentiate a variety of antibiotics against a multitude of MDR and susceptible bacteria. ...
In 2019, five million deaths associated with antimicrobial resistance were reported by The Centers for Disease Control and Prevention (CDC). Acinetobacter baumannii, a Gram-negative bacterial pathogen, is among the list of urgent threats. Previously, we reported 2-aminoimidazole (2-AI) adjuvants that potentiate macrolide activity against A. baumannii. In this study, we identify several of these adjuvants that sensitize A. baumannii to aminoglycoside antibiotics. Lead compounds 1 and 7 lower the tobramycin (TOB) minimum inhibitory concentration (MIC) against the TOB-resistant strain AB5075 from 128 μg/mL to 2 μg/mL at 30 μM. In addition, the lead compounds lower the TOB MIC against the TOB-susceptible strain AB19606 from 4 μg/mL to 1 μg/mL and 0.5 μg/mL, respectively, at 30 μM and 15 μM. The evolution of resistance to TOB and 1 in AB5075 revealed mutations in genes related to protein synthesis, the survival of bacteria under environmental stressors, bacteriophages, and proteins containing Ig-like domains.
... Previous research has shown that some diuretics, such as mannitol in osmotic diuresis, can protect against gentamicin-induced ototoxicity, as well as other chemotherapyinduced nephrotoxicity, such as cisplatin nephrotoxicity. 68 As a result, combining aminoglycosides with other diuretics, such as loop diuretics, increases ototoxicity in patient and animal models. 69 As a result, our findings suggest that combining amikacin with non-ototoxic diuretics can reduce its side effects and result in the rapid restoration of kidney function. ...
This study aimed to investigate the gene expression levels associated with nephrotoxic action of amikacin, as well as the post-treatment effect of diuretics on its nephrotoxic effects. Sixty male rats were divided equally into six groups, including the control group receiving saline intra-peritoneally (ip), and the five treated groups including therapeutic and double therapeutic dose groups, injected ip (15 and 30 mg/kg b.wt./day) respectively for seven days, and another two rat groups treated as therapeutic and double therapeutic dose groups then administered the diuretic orally for seven days and the last group received amikacin ip at a rate of 15 mg/kg/day for seven days, then given free access to water without diuretics for another seven days and was kept as a self-recovery group. Amikacin caused kidney injury, which was exacerbated by the double therapeutic dose, as evidenced by abnormal serum renal injury biomarkers, elevated renal MDA levels, inhibition of renal catalase and SOD enzyme activities, with renal degenerative and necrotic changes. Moreover, comet assays also revealed renal DNA damage. Interestingly, amikacin administration markedly elevated expression levels of the PARP-1, RIP1, TNF-α, IL-1β, and iNOS genes as compared to the control group. However, compared to the self-recovery group, post-amikacin diuretic treatment modulates amikacin-induced altered findings and alleviates amikacin nephrotoxic effects more efficiently. Our findings suggested the potential role of PARP-1 and RIPK1 expressions that influence the expression of proinflammatory cytokines such as IL-1β and TNF-α by exaggerating oxidative stress which may contribute to the pathogenesis of amikacin-induced nephrotoxicity.
... One of the earliest antibiotic classes, aminoglycosides, can have broad spectrum activity but are associated with widespread resistance in Gram-negative bacteria. They also have safety concerns, such as nephrotoxicity and ototoxicity, which make them less preferable treatment options than other antibiotics (Rosenberg et al., 2020). A new class of aminoglycosides known as 'neoglycosides' has recently been introduced in an attempt to circumvent the most common resistance mechanisms and improve the class's safety profile (Krause et al., 2016). ...
With the widespread use of antibiotics, bacterial infection-related morbidity and mortality have significantly declined, revolutionizing modern medicine. However, concerns have been raised concerning the negative effects of antibiotics on a number of physiological systems, including the health of male reproductive systems. The purpose of this in-depth review is to investigate and summarize the body of knowledge about the effects of antibiotics on male fertility. Antibiotics may have negative impacts on male reproductive characteristics, according to a growing body of studies over the past few decades. Several antibiotic groups, including fluoroquinolones, tetracyclines, and sulfonamides, have been linked to altered sperm quality, lower sperm count, impaired sperm motility, altered DNA integrity and morphology of sperm. Male reproductive health is thought to be negatively impacted by antibiotics in a multifactorial manner. It has been suggested that hormonal imbalances, oxidative stress, and disturbances of the delicate male reproductive system's balance may be the underlying mechanisms for the effects that have been observed. Additionally, changes brought on by antibiotics to the gut microbiota, which is known to be extremely important for overall health, may indirectly affect male fertility by altering systemic inflammation and hormone regulation. Additionally, the timing and length of antibiotic exposure appear to be important variables in determining their effect on male fertility, of which there is proof that repetitive or continued drug use may have more severe side effects. The possible negative effects of antibiotics on male fertility are highlighted in this review. Although the available data support a logical relationship between antibiotic usage and male reproductive health, more, well conducted research on humans are still required to clarify the underlying mechanisms and determine the clinical relevance of these results. Future studies in this field might open the door to stronger protections for male fertility while ensuring efficient control of bacterial infections.
... 8 In the clinical setting, careful dosing and regular monitoring of AGA blood levels are essential due to their potential adverse effects, including nephrotoxicity, cytotoxicity, and ototoxicity. 9,10 Moreover, the adulteration of animal-derived meat and dairy products with AGAs has raised concerns about their impact as endocrine disruptors in humans. 11,12 To address these concerns, health organizations worldwide have implemented strict regulations to monitor and control AGA residue levels in plant-and animal-derived food products, as well as in environmental samples and consumer goods. ...
The detection and monitoring of aminoglycoside antibiotics (AGAs) have become of utmost importance due to their widespread use in human and animal therapy, as well as the associated risks of exposure, toxicity, and the emergence of antimicrobial resistance. In this study, we successfully synthesized casein hydrolysate peptides-functionalized silver nanoparticles (CHPs@AgNPs) and employed them as a novel colorimetric analytical platform to demonstrate remarkable specificity and sensitivity toward AGAs. The colorimetric and spectral response of the CHPs@AgNPs was observed at 405 and 520 nm, showing a linear correlation with the concentration of streptomycin, a representative AGA. The color changes from yellow to orange provided a visual indication of the analyte concentration, enabling quantitative determination for real-world samples. The AgNP assay exhibited excellent sensitivity with dynamic ranges of approximately 200-650 and 100-700 nM for streptomycin-spiked tap water and dairy whey with limits of detection found to be ∼98 and 56 nM, respectively. The mechanism behind the selective aggregation of CHPs@AgNPs in the presence of AGAs involves the amine groups of the target analytes acting as molecular bridges for electrostatic coupling with hydroxyl or carboxyl functionalities of adjacent NPs, driving the formation of stable NP aggregates. The developed assay offers several advantages, making it suitable for various practical applications. It is characterized by its simplicity, rapidity, specificity, sensitivity, and cost-effectiveness. These unique features make the method a promising tool for monitoring water quality, ensuring food safety, and dealing with emergent issues of antibiotic resistance.
