scholarly journals Autonomous treatment of bacterial infections in vivo using antimicrobial micro- and nanomachines

2021 ◽  
Author(s):  
Xavier Arque ◽  
Marcelo D. T. Torres ◽  
Tania Patino ◽  
Andreia Boaro ◽  
Samuel Sanchez ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Target Area ◽  
Drug Resistant ◽  
Infection Site ◽  
Bacterial Strains ◽  
Resistance Development ◽  
Active Motion ◽  
Target Effects

The increasing resistance of bacteria to existing antibiotics constitutes a major public health threat globally. Most current antibiotic treatments are hindered by poor delivery to the infection site, leading to undesired off-target effects and drug resistance development and spread. Here, we describe micro- and nanomachines that effectively and autonomously deliver antibiotic payloads to the target area. The active motion and antimicrobial activity of the silica-based robots are driven by catalysis of the enzyme urease and antimicrobial peptides, respectively. These antimicrobial machines show micromolar bactericidal activity in vitro against different Gram-positive and Gram-negative pathogenic bacterial strains and act by rapidly depolarizing their membrane. Finally, they demonstrated autonomous anti-infective efficacy in vivo in a clinically relevant abscess infection mouse model. In summary, our machines combine navigation, catalytic conversion, and bactericidal capacity to deliver antimicrobial payloads to specific infection sites. This technology represents a much-needed tool to direct therapeutics to their target to help combat drug-resistant infections.

scholarly journals Imaging Sensitive and Drug-Resistant Bacterial Infection with [11C]-TMP: In Vitro and First-in-Human Evaluation

2021 ◽  
Author(s):  
Iris K Lee ◽  
Daniel A Jacome ◽  
Joshua K Cho ◽  
Vincent Tu ◽  
Anthony Young ◽  
...  
Keyword(s):  
Bacterial Infection ◽  
Mammalian Cells ◽  
Bacterial Infections ◽  
The Body ◽  
Response Monitoring ◽  
Drug Resistant ◽  
Bacterial Strains ◽  
Critical Question ◽  
In Vitro Uptake

Recently, several molecular imaging strategies have developed to image bacterial infections in humans. Nuclear approaches, specifically positron emission tomography (PET), affords sensitive detection and the ability to non-invasively locate infections deep within the body. Two key radiotracer classes have arisen: metabolic approaches targeting bacterial specific biochemical transformations, and antibiotic-based approaches that have inherent selectivity for bacteria over mammalian cells. A critical question for clinical application of antibiotic radiotracers is whether resistance to the template antibiotic abrogates specific uptake, thus diminishing the predictive value of the diagnostic test. We recently developed small-molecule PET radiotracers based on the antibiotic trimethoprim (TMP), including [11C]-TMP, and have shown their selectivity for imaging bacteria in preclinical models. Here, we measure the in vitro uptake of [11C]-TMP in pathogenic susceptible and drug-resistant bacterial strains. Both resistant and susceptible bacteria showed similar in vitro uptake, which led us to perform whole genome sequencing of these isolates to identify the mechanisms of TMP resistance that permit retained radiotracer binding. By interrogating these isolate genomes and a broad panel of previously sequenced strains, we reveal mechanisms where uptake or binding of TMP radiotracers can potentially be maintained despite the annotation of genes conferring antimicrobial resistance. Finally, we present several examples of patients with both TMP-sensitive and drug-resistant infections in our first-in-human experience with [11C]-TMP. This work underscores the ability of an antibiotic radiotracer to image bacterial infection in patients, which may allow insights into human bacterial pathogenesis, infection diagnosis, and antimicrobial response monitoring.

scholarly journals Novel Lytic Phages Protect Cells and Mice against Pseudomonas aeruginosa Infection

2021 ◽  
Author(s):  
Feng Chen ◽  
Xingjun Cheng ◽  
Jianbo Li ◽  
Xiefang Yuan ◽  
Xiuhua Huang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Mouse Models ◽  
Bacterial Infections ◽  
Phage Therapy ◽  
Inflammatory Responses ◽  
Multi Drug Resistance ◽  
Bacterial Strains ◽  
Genetic Traits

With the fast emergence of serious antibiotic resistance and the lagged discovery of novel antibacterial drugs, phage therapy for pathogenic bacterial infections has acquired great attention in the clinics. However, development of therapeutic phages also faces tough challenges, such as laborious screening and time to generate effective phage drugs since each phage may only lyse a narrow scope of bacterial strains. Identifying highly effective phages with broad host ranges is crucial for improving phage therapy. Here, we isolated and characterized several lytic phages from various environments specific for Pseudomonas aeruginosa by testing their growth, invasion, host ranges, and potential for killing targeted bacteria. Importantly, we identified several therapeutic phages (HX1, PPY9, and TH15) with broad host ranges to lyse laboratory strains and clinical isolates of P. aeruginosa with multi-drug resistance (MDR) both in vitro and in mouse models. In addition, we analyzed critical genetic traits related to the high-level broad host coverages by genome sequencing and subsequent computational analysis against known phages. Collectively, our findings establish that these novel phages may have potential for further development as therapeutic options for patients who fail to respond to conventional treatments. IMPORTANCE Novel lytic phages isolated from various environmental settings were systematically characterized for their critical genetic traits, morphology structures, host ranges against laboratory strains and clinical multi-drug resistant (MDR) Pseudomonas aeruginosa, and antibacterial capacity both in vitro and in mouse models. First, we characterized the genetic traits and compared with other existing phages. Furthermore, we utilized acute pneumonia induced by laboratorial strain PAO1, and W19, an MDR clinical isolate and chronic pneumonia by agar beads laden with FDR1, a mucoid phenotype strain isolated from the sputum of a cystic fibrosis (CF) patient. Consequently, we found that these phages not only suppress bacteria in vitro but also significantly reduce the infection symptom and disease progression in vivo, including lowered bug burdens, inflammatory responses and lung injury in mice, suggesting that they may be further developed as therapeutic agents against MDR P. aeruginosa.

scholarly journals Mechanisms of Resistance in Bacteria: An Evolutionary Approach

2013 ◽  
Vol 7 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Ana Martins ◽  
Attila Hunyadi ◽  
Leonard Amaral
Keyword(s):  
Bacterial Infections ◽  
Chemotherapeutic Agents ◽  
World Health ◽  
Bacterial Strains ◽  
Mechanisms Of Resistance ◽  
New Perspective ◽  
Health Organization ◽  
Mycobacteria Tuberculosis

Acquisition of resistance is one of the major causes of failure in therapy of bacterial infections. According to the World Health Organization (WHO), thousands of deaths caused by Salmonella sp., Escherichia coli, Staphylococcus aureus or Mycobacteria tuberculosis are due to failure in therapy caused by resistance to the chemotherapeutic agents. Understanding the mechanisms of resistance acquisition by the bacterial strains is therefore essential to prevent and overcome resistance. However, it is very difficult to extrapolate from in vitro studies, where the variables are far less and under constant control, as compared to what happens in vivo where the chosen chemotherapeutic, its effective dose, and the patient’s immune system are variables that differ substantially case-by-case. The aim of this review is to provide a new perspective on the possible ways by which resistance is acquired by the bacterial strains within the patient, with a special emphasis on the adaptive response of the infecting bacteria to the administered antibiotic.

scholarly journals Engineered Remolding and Application of Bacterial Membrane Vesicles

2021 ◽  
Vol 12 ◽  
Author(s):  
Li Qiao ◽  
Yifan Rao ◽  
Keting Zhu ◽  
Xiancai Rao ◽  
Renjie Zhou
Keyword(s):  
Drug Delivery ◽  
Bacterial Infections ◽  
Drug Delivery Systems ◽  
Membrane Vesicles ◽  
Delivery Systems ◽  
Bacterial Membrane ◽  
Wild Type ◽  
Bacterial Strains

Bacterial membrane vesicles (MVs) are produced by both Gram-positive and Gram-negative bacteria during growth in vitro and in vivo. MVs are nanoscale vesicular structures with diameters ranging from 20 to 400 nm. MVs incorporate bacterial lipids, proteins, and often nucleic acids, and can effectively stimulate host immune response against bacterial infections. As vaccine candidates and drug delivery systems, MVs possess high biosafety owing to the lack of self-replication ability. However, wild-type bacterial strains have poor MV yield, and MVs from the wild-type strains may be harmful due to the carriage of toxic components, such as lipopolysaccharides, hemolysins, enzymes, etc. In this review, we summarize the genetic modification of vesicle-producing bacteria to reduce MV toxicity, enhance vesicle immunogenicity, and increase vesicle production. The engineered MVs exhibit broad applications in vaccine designs, vaccine delivery vesicles, and drug delivery systems.

scholarly journals In vivo monitoring of viable bacteria by SPECT using 99mTc-HYNIC(GH)2-UBI 29-41 and 99mTc-HYNIC(Tricine)2-UBI 29-41

2021 ◽  
Author(s):  
Yuri Nishiyama ◽  
Tomoya Uehara ◽  
Kenichi Okazaki ◽  
Hideki Maki ◽  
Kohji Abe ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Radiochemical Purity ◽  
Bacterial Count ◽  
Infection Site ◽  
Cell Infection ◽  
Peptide Labeling ◽  
Viable Bacteria ◽  
Over Time

Abstract Background: The number of bacterial infections that—for various reasons—are challenging to cure continues to increase. One such reason is persister cell infection. To investigate persister formation and persister infections, viable bacteria must be evaluated in the same animal over time. In this study, the feasibility of monitoring viable bacteria by SPECT using two labeled peptides was evaluated. Results: Two types of ubiquicidin (UBI) 29-41 labeled with technetium-99m, 99mTc-HYNIC(GH)2-UBI 29-41 and 99mTc-HYNIC(Tricine)2-UBI 29-41, were synthesized. The in vitro binding of these labeled peptides to Staphylococcus aureus was measured. For the in vivo study, each labeled peptide was injected into S. aureus infected mouse thigh after treatment with various doses of ciprofloxacin (CPFX). Two hours after injection, the accumulation of each labeled peptide at the infection site was assessed by SPECT, and then the number of viable bacteria was determined from the accumulation detected. The peptide labeling was successful, and the radiochemical purity was 91±9% (GH, n=8) and 100% (Tricine, n=8). The in vitro binding of the labeled peptides to S. aureus (5×108 cfu) without serum was 78.9% (GH) and 85.5% (Tricine) of the total 99mTc activity. With serum, the binding rate was 67.5% (GH) and 13.3% (Tricine). The accumulation of labeled peptide was calculated from the SPECT images, and that in the bacterial infection site (left thigh) was higher than that in the non-infection site (right thigh) for both peptides. Good correlation was found between the target-to-non-target (T/NT) ratios of each labeled peptide and the viable bacterial count at the infection site, and 99mTc-HYNIC(Tricine)2-UBI 29-41 had a wider range than 99mTc-HYNIC(GH)2-UBI 29-41.Conclusion: Using the SPECT/labeled peptide method, it was possible to monitor viable bacterial count in the range 103–108 cfu, which is appropriate for tracking viable bacterial counts in the same animal over time.

scholarly journals Efficacy of OH-CATH30 and Its Analogs against Drug-Resistant BacteriaIn Vitroand in Mouse Models

2012 ◽  
Vol 56 (6) ◽  
pp. 3309-3317 ◽  
Author(s):  
Sheng-An Li ◽  
Wen-Hui Lee ◽  
Yun Zhang
Keyword(s):  
Mouse Models ◽  
Bacterial Infections ◽  
Resistant Bacteria ◽  
Infection Model ◽  
Drug Resistant ◽  
Content Type ◽  
E Coli ◽  
Drug Resistant Bacteria

ABSTRACTAntimicrobial peptides (AMPs) have been considered alternatives to conventional antibiotics for drug-resistant bacterial infections. However, their comparatively high toxicity toward eukaryotic cells and poor efficacyin vivohamper their clinical application. OH-CATH30, a novel cathelicidin peptide deduced from the king cobra, possesses potent antibacterial activityin vitro. The objective of this study is to evaluate the efficacy of OH-CATH30 and its analog OH-CM6 against drug-resistant bacteriain vitroandin vivo. The MICs of OH-CATH30 and OH-CM6 ranged from 1.56 to 12.5 μg/ml against drug-resistant clinical isolates of several pathogenic species, includingEscherichia coli,Pseudomonas aeruginosa, and methicillin-resistantStaphylococcus aureus. The MICs of OH-CATH30 and OH-CM6 were slightly altered in the presence of 25% human serum. OH-CATH30 and OH-CM6 killedE. coliquickly (within 60 min) by disrupting the bacterial cytoplasmic membrane. Importantly, the 50% lethal doses (LD50) of OH-CATH30 and OH-CM6 in mice following intraperitoneal (i.p.) injection were 120 mg/kg of body weight and 100 mg/kg, respectively, and no death was observed at any dose up to 160 mg/kg following subcutaneous (s.c.) injection. Moreover, 10 mg/kg OH-CATH30 or OH-CM6 significantly decreased the bacterial counts as well as the inflammatory response in a mouse thigh infection model and rescued infected mice in a bacteremia model induced by drug-resistantE. coli. Taken together, our findings demonstrate that the natural cathelicidin peptide OH-CATH30 and its analogs exhibit relatively low toxicity and potent efficacy in mouse models, indicating that they may have therapeutic potential against the systemic infections caused by drug-resistant bacteria.

Exploring the therapeutic potential of atorvastatin against Gram-positive and Gram-negative bacteria: In-silico, In-vitro and In- vivo evidence

2019 ◽  
Vol 19 ◽  
Author(s):  
Kamal Sethi ◽  
Arti Singh ◽  
Anoop Kumar
Keyword(s):  
Mtt Assay ◽  
In Silico ◽  
Bacterial Infections ◽  
Therapeutic Potential ◽  
In Vivo Studies ◽  
Bacterial Strains ◽  
Study Results ◽  
Reference Ligand

The incidences of opportunistic bacterial infections have increased from the past two decades or threaten to increase in the near future. Inspite of the availability of various classes of antibiotics, bacterial infections are not handled properly.Thus, in the present study, we have repurposed atorvastatin against various types of bacterial strains by using in-silico, in-vitro, and in-vivo studies. Further, preliminary safety study was conducted using MTT assay. In-silico study results have revealed that atorvastatin hasgood interaction with various targets of bacterial cell as that of reference ligand. However, under in-vitro conditions, we have foundthat atorvastatin was effective at higher concentration(>128 μg/ml) against various bacterial strains. Thus, further, atorvastatin was tested in combination with standard antibiotics and has shown synergistic effect. The MTT assay results have revealed non-cytotoxic activity of atorvastatin. In conclusion, atorvastatin in combination with standard drugs could be developed as an antibacterial agent.

scholarly journals Topically Applied Bacteriophage to Control Multi-Drug Resistant Klebsiella pneumoniae Infected Wound in a Rat Model

Antibiotics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1048
Author(s):  
Mohamed S. Fayez ◽  
Toka A. Hakim ◽  
Mona M. Agwa ◽  
Mohamed Abdelmoteleb ◽  
Rania G. Aly ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Rat Model ◽  
Bacterial Infections ◽  
Control Group ◽  
Lytic Phage ◽  
Drug Resistant ◽  
Infected Wound ◽  
Specific Phage

(Background): Multi-drug-resistant Klebsiella pneumoniae (MDR-KP) has steadily grown beyond antibiotic control. Wound infection kills many patients each year, due to the entry of multi-drug resistant (MDR) bacterial pathogens into the skin gaps. However, a bacteriophage (phage) is considered to be a potential antibiotic alternative for treating bacterial infections. This research aims at isolating and characterizing a specific phage and evaluate its topical activity against MDR-KP isolated from infected wounds. (Methods): A lytic phage ZCKP8 was isolated by using a clinical isolate KP/15 as a host strain then characterized. Additionally, phage was assessed for its in vitro host range, temperature, ultraviolet (UV), and pH sensitivity. The therapeutic efficiency of phage suspension and a phage-impeded gel vehicle were assessed in vivo against a K. pneumoniae infected wound on a rat model. (Result): The phage produced a clear plaque and was classified as Siphoviridae. The phage inhibited KP/15 growth in vitro in a dose-dependent pattern and it was found to resist high temperature (˂70 °C) and was primarily active at pH 5; moreover, it showed UV stability for 45 min. Phage-treated K. pneumoniae inoculated wounds showed the highest healing efficiency by lowering the infection. The quality of the regenerated skin was evidenced via histological examination compared to the untreated control group. (Conclusions): This research represents the evidence of effective phage therapy against MDR-KP.

In vitro and in vivo combined antibacterial effect of levofloxacin/silver co-loaded electrospun fibrous membranes

2017 ◽  
Vol 5 (36) ◽  
pp. 7632-7643 ◽  
Author(s):  
Ziliang Song ◽  
Yongjie Ma ◽  
Guanggai Xia ◽  
Yao Wang ◽  
Wasim Kapadia ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Antibacterial Effect ◽  
Drug Resistant ◽  
Fibrous Membranes ◽  
Low Dosage

The Lev@MSN@Ag–PLLA fibers provided an advanced synergistic antibacterial nanoplatform of low dosage for the treatment of drug-resistant bacterial infections.

scholarly journals Therapeutic Efficacy of Bacteriophages

2021 ◽  
Author(s):  
Ramasamy Palaniappan ◽  
Govindan Dayanithi
Keyword(s):  
Antibiotic Therapy ◽  
Antibiotic Treatment ◽  
Bacterial Infections ◽  
Bacterial Species ◽  
Resistant Bacteria ◽  
Drug Resistant ◽  
Bacteriophage Therapy ◽  
Drug Resistant Bacteria

Bacteriophages are bacterial cell-borne viruses that act as natural bacteria killers and they have been identified as therapeutic antibacterial agents. Bacteriophage therapy is a bacterial disease medication that is given to humans after a diagnosis of the disease to prevent and manage a number of bacterial infections. The ability of phage to invade and destroy their target bacterial host cells determines the efficacy of bacteriophage therapy. Bacteriophage therapy, which can be specific or nonspecific and can include a single phage or a cocktail of phages, is a safe treatment choice for antibiotic-resistant and recurrent bacterial infections after antibiotics have failed. A therapy is a cure for health problems, which is administered after the diagnosis of the diseases in the patient. Such non-antibiotic treatment approaches for drug-resistant bacteria are thought to be a promising new alternative to antibiotic therapy and vaccination. The occurrence, biology, morphology, infectivity, lysogenic and lytic behaviours, efficacy, and mechanisms of bacteriophages’ therapeutic potentials for control and treatment of multidrug-resistant/sensitive bacterial infections are discussed. Isolation, long-term storage and recovery of lytic bacteriophages, bioassays, in vivo and in vitro experiments, and bacteriophage therapy validation are all identified. Holins, endolysins, ectolysins, and bacteriocins are bacteriophage antibacterial enzymes that are specific. Endolysins cause the target bacterium to lyse instantly, and hence their therapeutic potential has been explored in “Endolysin therapy.” Endolysins have a high degree of biochemical variability, with certain lysins having a wider bactericidal function than antibiotics, while their bactericidal activities are far narrower. Bacteriophage recombinant lysins (chimeric streptococcal–staphylococcal constructs) have high specificity for a single bacterial species, killing only that species (lysin (CF-301) is focused to kill methicillin resistant Staphylococcus aureus (MRSA)), while other lysins have a broader lytic activity, killing several different bacterial species and hence the range of bactericidal activity. New advances in medicine, food safety, agriculture, and biotechnology demonstrate molecular engineering, such as the optimization of endolysins for particular applications. Small molecule antibiotics are replaced by lysins. The chapter discusses the occurrences of lytic phage in pathogenic bacteria in animals and humans, as well as the possible therapeutic effects of endolysins-bacteriophage therapy in vivo and in vitro, demonstrating the utility and efficacy of the therapy. Further developments in the bacteriophage assay, unique molecular-phage therapy, or a cocktail of phage for the control of a broad range of drug-resistant bacteria-host systems can promote non-antibiotic treatment methods as a viable alternative to conventional antibiotic therapy.

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