Fosfomycin and nitrofurantoin: classic antibiotics and perspectives

Extreme diversity of phage amplification rates and phage-antibiotic interactions revealed by PHORCE

Growth rate plays a fundamental role in microbiology and serves as an important proxy for fitness in evolution. While high-throughput measurements of bacterial growth rates are easily performed in any microbiology laboratory, similar methods are lacking for bacteriophages. This gap hinders systematic comparisons of important phage phenotypes, such as their amplification rate in bacterial populations and their bactericidal effect, across different phages and environmental conditions. Here, we show that the amplification rate of lytic phages can be quantified by analyzing bacterial population growth and collapse dynamics under phage predation using a parsimonious mathematical model - an approach termed Phage-Host Observation for Rate estimation from Collapse Events (PHORCE). We found that the resulting phage amplification rate captures the bactericidal effect independent of initial phage and bacterial population sizes for fast-growing hosts and adsorption-limited phages. Using high-throughput PHORCE, we found that the amplification rates of Escherichia coli phages vary widely by more than three orders of magnitude. Furthermore, our approach suggests that phage-antibiotic interactions are predominantly determined by the antibiotic, and not by the phage. In particular, the ribosome-inhibiting antibiotic doxycycline generally showed antagonism with phage amplification, whereas the DNA-damaging antibiotic nitrofurantoin was synergistic. This framework provides a means to quantitatively characterize phage phenotypes and may facilitate future high-throughput phage screens for antibacterial applications.

Exploring the Potential of Nitrofurantoin for Infection Control in Regenerative Endodontics: In Vitro Study

INTRODUCTION

This study assessed a new antimicrobial paste formulation containing nitrofurantoin for regenerative endodontics against multispecies biofilms.

METHODS

Four groups of 11 single-root teeth each were tested: Negative control group (brain-heart infusion broth + micro-organisms); Hoshino 1 conventional tri-antibiotic paste group (1:1:1 ratio); Hoshino 5 group (5:5:5 ratio); Experimental group with nitrofurantoin, ciprofloxacin, and metronidazole. Minimum inhibitory concentrations of each antimicrobial were determined. A polymicrobial biofilm (Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans) was created in root canals, and pastes were inserted for 3 minutes with lentulo. After 7 days, samples were sonicated and spectrophotometrically analyzed. Microbiological assays, plasma membrane permeabilization, confocal laser scanning microscopy, and scanning electron microscopy evaluated biofilm eradication. Statistical significance was set at P < .05.

RESULTS

Spectrophotometry indicated Experimental group outperformed Hoshino 1 group and Negative control group (P < .05), with results similar to Hoshino 5 group (P > .05). Experimental group showed increased membrane damage compared to Hoshino 1 group and Hoshino 5 group. Confocal laser scanning microscopy and scanning electron microscopy revealed fewer microorganisms and no residual biofilm in Experimental group.

CONCLUSIONS

Substituting minocycline with nitrofurantoin in the paste effectively reduced microorganism counts in root canals system.

Long-term forecast for antibacterial drug consumption in Germany using ARIMA models

The increasing supply shortages of antibacterial drugs presents significant challenges to public health in Germany. This study aims to predict the future consumption of the ten most prescribed antibacterial drugs in Germany up to 2040 using ARIMA (Auto Regressive Integrated Moving Average) models, based on historical prescription data. This analysis also evaluates the plausibility of the forecasts. Our findings represent one of the first long-term national forecasts for antibacterial drug consumption. ARIMA(0,1,0), a random walk model with drift, is the best-fitting model to capture trends across all antibacterial drugs. While more complex models offer greater detail, they seem less suitable for long-term forecasting. In a short-term forecast of 5 and 10 years, predictions between significant models vary very little. Predictions indicate increasing DDD-prescriptions for amoxicillin, cefuroxime axetil, amoxicillin clavulanic acid, clindamycin, azithromycin, nitrofurantoin, and ciprofloxacin, while declines are forecasted for doxycycline, phenoxymethylpenicillin, and sulfamethoxazole-trimethoprim. The reliability of the predictions varies. Forecasts for azithromycin, phenoxymethylpenicillin, and sulfamethoxazole-trimethoprim are likely accurate, whereas uncertainties exist for doxycycline, amoxicillin clavulanic acid, nitrofurantoin, and ciprofloxacin, though general trends appear valid. Potential discrepancies may arise in the predictions for amoxicillin, cefuroxime axetil, and clindamycin. These forecasts highlight the urgent need for proactive healthcare planning to prevent future shortages, a problem underscored by recent supply disruptions in Germany. Future research should extend this analysis to the development of bacterial resistance and other frequently used drug classes.

Structure-guided identification of potential inhibitors of MurB from S. typhimurium LT2 strain: towards therapeutic development against multidrug resistance

MurB or UDP-N-acetylenolpyruvoylglucosamine reductase (EC 1.3.1.98) is involved in the synthesis of bacterial cell walls of Salmonella typhimurium LT2 as it catalyzes one of the reactions in the formation of peptidoglycan. Since the enzyme is required for bacterial survival and is not present in humans, this makes it an ideal drug target, for multidrug resistance (MDR) strains. Thus, we proceeded with the identification of novel inhibitors of MurB that could overcome the existing resistance. The potential leads were identified from the PubChem library by selecting compounds with high structural similarity to the known inhibitors of MurB. These compounds were then taken through molecular docking studies and were further assessed based on physicochemical and ADMET characteristics. Regarding binding efficiency and drug-likeliness, two hit molecules with PubChem CID:10416900 and CID:14163894 were identified against MurB. Both compounds were closely bound to the MurB active site and did not induce any substantial structural changes in the MurB structure during all-atom molecular dynamics (MD) simulations and MM-PBSA studies. These compounds showed higher potential than the existing inhibitors and stood out as promising leads for the development of therapeutic inhibitors of MurB. The findings of the study, therefore, point to the viability of these compounds in the treatment of bacterial infections, thus enhancing the quality of patient care and disease management. More studies and experimental validation are required to explore their clinical use to the optimum.

The Impact of Urban Pollution on Plasmid-Mediated Resistance Acquisition in Enterobacteria from a Tropical River

Background: The exposure of environmental bacteria to contaminants in aquatic ecosystems accelerates the dissemination of antibiotic-resistance genes (ARGs) through horizontal gene transfer (HGT). Methods: In this study, we sampled three locations along a contamination gradient of a polluted river, focusing on isolating Enterobacteria from the surface waters to investigate the relationship between urban pollution and antibiotic resistance. The genomes of 15 isolates (5 per site) were sequenced to identify plasmid-borne ARGs and their association with resistance phenotypes. Results: Isolates from the site with the highest contamination (Site 3) showeda larger number of ARGs, plasmids, and resistance phenotypes. Notably, one of the isolates analyzed, E. coli A231-12, exhibited phenotypic resistance to seven antibiotics, presumably conferred by a single plasmid carrying 12 ARGs. Comparative analysis of this plasmid revealed its close evolutionary relationship with another IncH plasmid hosted by Salmonella enterica, underscoring its high ARG burden in the aquatic environment. Other plasmids identified in our isolates carried sul and dfrA genes, conferring resistance to trimethoprim/sulfamethoxazole, a commonly prescribed antibiotic combination in clinical settings. Conclusions: These results highlight the critical need to expand research on the link between pollution and plasmid-mediated antimicrobial resistance in aquatic ecosystems, which can act as reservoirs of ARGs.

Bacteriological and molecular study of fosfomycin resistance in uropathogenic Escherichia coli

The identification of genes associated with resistance has the potential to facilitate the development of novel diagnostic tests and treatment methods. The objective of this study was to examine the antibiotic resistance and Fosfomycin resistance genes in uropathogenic Escherichia coli (UPEC) in patients in Baghdad, Iraq. After analyzing 250 urine samples using various identification methods, including the examination of morphological characteristics, biochemical tests, and genetic detection, it was determined that E. coli was the most common bacteria present, accounting for 63.6% of the samples. Antibiotic susceptibility testing showed a significant prevalence of resistance to various antibiotics, with 99.3% of E. coli isolates exhibiting multiple drug resistance (MDR). Fosfomycin showed antibacterial properties against UPEC. The minimum inhibitory concentration (MIC) ranged from 512 to 1024 μg/mL, while the minimum bactericidal concentration (MBC) was 2048 μg/mL. In the time-kill assay, fosfomycin was effective against fosfomycin-resistant isolates within 8-12 h. The genetic determinants associated with fosfomycin resistance were examined through the utilization of polymerase chain reaction (PCR). The findings indicated that the genes murA, glpT, and cyaA were detected in all the isolates when genomic DNA was used as a template. However, all the tests yielded negative results when plasmid was used as a template. The genes fosA3 and fosA4 were detected in 8.6% and 5% of the isolates when genomic DNA was used as a template. When plasmid was used as a template, the genes fosA3 and fosA4 were found in 5.7% and 2.9% of the isolates, respectively. In conclusion, there is an increasing problem with antibiotic resistance in UPEC, with elevated rates of resistance to several antibiotics. The study also offers novel insights into the genetic foundation of fosfomycin resistance in UPEC.

In Vitro Activities of Oxazolidinone Antibiotics Alone and in Combination with C-TEMPO against Methicillin-Resistant Staphylococcus aureus Biofilms

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a global health concern. The propensity of MRSA to form biofilms is a significant contributor to its pathogenicity. Strategies to treat biofilms often involve small molecules that disperse the biofilm into planktonic cells. Linezolid and, by extension, theoxazolidinones have been developed to treat infections caused by Gram-positive bacteria such as MRSA. However, the clinical development of these antibiotics has mainly assessed the susceptibility of planktonic cells to the drug. Previous studies evaluating the anti-biofilm activity of theoxazolidinones have mainly focused on the biofilm inhibition of Enterococcus faecalis and methicillin-sensitive Staphylococcus aureus, with only a few studies investigating the activity of oxazolidinones for eradicating established biofilms for these species. Very little is known about the ability of oxazolidinones to eradicate MRSA biofilms. In this work, five oxazolidinones were assessed against MRSA biofilms using a minimum biofilm eradication concentration (MBEC) assay. All oxazolidinones had inherent antibiofilm activity. However, only ranbezolid could completely eradicate MRSA biofilms at clinically relevant concentrations. The susceptibility of the MRSA biofilms to ranbezolid was synergistically enhanced by coadministration with the nitroxide biofilm dispersal agent C-TEMPO. We presume that ranbezolid acts as a dual warhead drug, which combines the mechanism of action of the oxazolidinones with a nitric oxide donor or cytotoxic drug.

Resensitisation of Methicillin-Resistant Staphylococcus aureus to Conventional Antibiotics in the Presence of an Engineered Enzybiotic

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most dreadful pathogens relevant in community and nosocomial-related infections around the world. Resensitising MRSA to antibiotics, once it became resistant, was a tough choice due to the high adaptability of this bacteria to savage conditions. This study aimed to create a chimeric enzybiotic against MRSA and test its efficiency, either individually or in combination with antibiotics. The novel enzybiotic BAC100 was constructed by fusing the catalytic domain from the bacteriocin BacL1 from Enterococcus faecalis with the cell-wall-binding domain from protein P17 of Staphylococcus aureus bacteriophage ϕ44AHJD. Apart from its partial lone activity, BAC100 was found to resensitise the MRSA strain to traditional antibiotics, including ampicillin and tetracycline. Both drugs were able to reduce live MRSA cells by 85 and 90%, respectively, within 60 min of treatment together with BAC100. However, no significant activity was observed against MRSA when these drugs were tested independently, pointing to the inherent resistance of MRSA against these conventional antibiotics. To our knowledge, this is one of the first instances where an engineered enzybiotic was found to resensitise MRSA to conventional antibiotics. This study will pave the way for the development of similar peptides that can be used together with antibiotics against gruesome pathogens of clinical importance.

Nitrofurantoin: properties and potential in treatment of urinary tract infection: a narrative review

Nitrofurantoin (NF), a wide-spectrum antibiotic accessible since 1953, is utilized widely to treat urinary tract infections as it usually stays active against drug-resistant uropathogen. The use of Nitrofurantoin has increased exponentially since new guidelines have repositioned it as first-line therapy for uncomplicated lower urinary tract infection (UTI). To, although fluoroquinolones are usually used to re-evaluate the first- and second-line therapies for treating uncomplicated UTI, their level of utilization is thought to be inappropriately excessive and will eventually have a detrimental impact; thus, we hypothesize that NF might be the best choice for this condition, because of its low frequency of utilization and its high susceptibility in common UTI pathogens. It can be concluded from this review that NF can be considered as the most effective drug in the treatment of acute urinary infection, but due to the long-term side effects of this drug, especially in elderly patients, it is essential to introduce some criteria for prescribing NF in cases of chronic UTI.

Luteolin 4'-Neohesperidoside Inhibits Clinically Isolated Resistant Bacteria In Vitro and In Vivo

Multidrug resistance (MDR) pathogens are usually associated with higher morbidity and mortality rates. Flavonoids are good candidates for the development of new potential antimicrobials. This research investigated whether luteolin 4'-neohesperidoside (L4N) has antibacterial and synergistic activities against four antibiotic-resistant pathogens: methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae, fosA-positive shiga toxin producing the Escherichia coli serogroup O111 (STEC O111), and Bacillus cereus. In vitro antimicrobial susceptibility testing revealed highly potent anti-MRSA (MIC of 106.66 ± 6.95 µg/mL), anti-K. pneumoniae (MIC of 53.33 ± 8.47 µg/mL) and anti-STEC O111 (MIC of 26.66 ± 5.23 µg/mL) activities. Significant synergistic combination was clearly noted in the case of gentamycin (GEN) against Gram-negative bacteria. In the case of B. cereus, the combination of vancomycin (VAN) with L4N could efficiently inhibit bacterial growth, despite the pathogen being VAN-resistant (MIC of 213.33 ± 7.9 µg/mL). In vivo evaluation of L4N showed significant decreases in K. pneumoniae and STEC shedding and colonization. Treatment could significantly diminish the levels of pro-inflammatory markers, tumor necrosis factor-alpha (TNF-α), and immunoglobulin (IgM). Additionally, the renal and pulmonary lesions were remarkably enhanced, with a significant decrease in the bacterial loads in the tissues. Finally, this study presents L4N as a potent substitute for traditional antibiotics with anti-STEC O111 and anti-K. pneumoniae potential, a finding which is reported here for the first time.

Synergistic Antibacterial Potential of Greenly Synthesized Silver Nanoparticles with Fosfomycin Against Some Nosocomial Bacterial Pathogens

Introduction

A considerable number of morbidities and fatalities occur worldwide as a result of the multidrug resistant microorganisms that cause a high prevalence of nosocomial bacterial infections. Hence, the current investigation was conducted to evaluate the antibacterial potency of green fabricated silver nanoparticles (AgNPs) against four different nosocomial pathogens.

Methods

The flower extract of Hibiscus sabdariffa mediated green fabrication of AgNPs and their physicochemical features were scrutinized using different techniques. Antimicrobial activity of the biogenic AgNPs and their synergistic patterns with fosfomycin antibiotic were evaluated using disk diffusion assay.

Results and Discussion

UV spectral analysis affirmed the successful formation of AgNPs through the detection of broad absorption band at 395 and 524 nm, indicating the surface plasmon resonance of the biofabricated AgNPs. In this setting, the biofabricated AgNPs demonstrated average particle size of 58.682 nm according to transmission electron microscope (TEM) micrographs. The detected hydrodynamic diameter was higher than that noticed by TEM analysis, recording 72.30 nm in diameter and this could be attributed to the action of capping agents, which was confirmed by Fourier Transform Infrared (FT-IR) analysis. Disk diffusion assay indicated the antibacterial potency of biogenic AgNPs (50 μg/disk) against Enterobacter cloacae, Methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli strains with relative inhibition zone diameters of 12.82 ± 0.36 mm, 14.54 ± 0.15 mm, 18.35 ± 0.24 mm and 21.69 ± 0.12 mm, respectively. In addition, E. coli was found to be the most susceptible strain to the biogenic AgNPs. However, the highest synergistic pattern of AgNPs-fosfomycin combination was detected against K. pneumonia strain recording relative synergistic percentage of 64.22%. In conclusion, the detected synergistic efficiency of AgNPs and the antibiotic fosfomycin highlight the potential for utilizing this combination in the biofabrication of effective antibacterial agents against nosocomial pathogens.

R R, L. F L, M.C.G DR, N.B C, S.C D, O. L F. Advances and perspectives for antimicrobial peptide and combinatory therapies

Antimicrobial peptides (AMPs) have shown cell membrane-directed mechanisms of action. This specificity can be effective against infectious agents that have acquired resistance to conventional drugs. The AMPs' membrane-specificity and their great potential to combat resistant microbes has brought hope to the medical/therapeutic scene. The high death rate worldwide due to antimicrobial resistance (AMR) has pushed forward the search for new molecules and product developments, mainly antibiotics. In the current scenario, other strategies including the association of two or more drugs have contributed to the treatment of difficult-to-treat infectious diseases, above all, those caused by bacteria. In this context, the synergistic action of AMPs associated with current antibiotic therapy can bring important results for the production of new and effective drugs to overcome AMR. This review presents the advances obtained in the last 5 years in medical/antibiotic therapy, with the use of products based on AMPs, as well as perspectives on the potentialized effects of current drugs combined with AMPs for the treatment of bacterial infectious diseases.