scholarly journals A novel chemical biology and computational approach to expedite the discovery of new-generation polymyxins against life-threatening Acinetobacter baumannii

2021 ◽  
Author(s):  
Xukai Jiang ◽  
Nitin A. Patil ◽  
Mohammad A. K. Azad ◽  
Hasini Wickremasinghe ◽  
Heidi Yu ◽  
...  

Multidrug-resistant Gram-negative bacteria have been an urgent threat to global public health. Novel antibiotics are desperately needed to combat these 'superbugs'.

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yuan Liu ◽  
Ziwen Tong ◽  
Jingru Shi ◽  
Yuqian Jia ◽  
Tian Deng ◽  
...  

AbstractAntimicrobial resistance has been a growing concern that gradually undermines our tradition treatment regimens. The fact that few antibacterial drugs with new scaffolds or targets have been approved in the past two decades aggravates this crisis. Repurposing drugs as potent antibiotic adjuvants offers a cost-effective strategy to mitigate the development of resistance and tackle the increasing infections by multidrug-resistant (MDR) bacteria. Herein, we found that benzydamine, a widely used non‐steroidal anti‐inflammatory drug in clinic, remarkably potentiated broad-spectrum antibiotic-tetracyclines activity against a panel of clinically important pathogens, including MRSA, VRE, MCRPEC and tet(X)-positive Gram-negative bacteria. Mechanistic studies showed that benzydamine dissipated membrane potential (▵Ψ) in both Gram-positive and Gram-negative bacteria, which in turn upregulated the transmembrane proton gradient (▵pH) and promoted the uptake of tetracyclines. Additionally, benzydamine exacerbated the oxidative stress by triggering the production of ROS and suppressing GAD system-mediated oxidative defensive. This mode of action explains the great bactericidal activity of the doxycycline-benzydamine combination against different metabolic states of bacteria involve persister cells. As a proof-of-concept, the in vivo efficacy of this drug combination was evidenced in multiple animal infection models. These findings indicate that benzydamine is a potential tetracyclines adjuvant to address life-threatening infections by MDR bacteria.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0256556
Author(s):  
Abera Abdeta ◽  
Adane Bitew ◽  
Surafel Fentaw ◽  
Estifanos Tsige ◽  
Dawit Assefa ◽  
...  

Background Multidrug resistant, extremely drug-resistant, pan-drug resistant, carbapenem-resistant, and carbapenemase-producing gram-negative bacteria are becoming more common in health care settings and are posing a growing threat to public health. Objective The study was aimed to detect and phenotypically characterize carbapenem no- susceptible gram-negative bacilli at the Ethiopian Public Health Institute. Materials and methods A prospective cross-sectional study was conducted from June 30, 2019, to May 30, 2020, at the national reference laboratory of the Ethiopian Public Health Institute. Clinical samples were collected, inoculated, and incubated for each sample in accordance with standard protocol. Antimicrobial susceptibility testing was conducted using Kirby-Bauer disk diffusion method. Identification was done using the traditional biochemical method. Multidrug-resistant and extensively drug-resistant isolates were classified using a standardized definition established by the European Centre for Disease Prevention and Control and the United States Centers for Disease Prevention and Control. Gram-negative organisms with reduced susceptibility to carbapenem antibiotics were considered candidate carbapenemase producers and subjected to modified carbapenem inactivation and simplified carbapenem inactivation methods. Meropenem with EDTA was used to differentiate metallo-β-lactamase (MBL) from serine carbapenemase. Meropenem (MRP)/meropenem + phenylboronic acid (MBO) were used to differentiate Klebsiella pneumoniae carbapenemase (KPC) from other serine carbapenemase producing gram-negative organisms. Results A total of 1,337 clinical specimens were analyzed, of which 429 gram-negative bacterial isolates were recovered. Out of 429 isolates, 319, 74, and 36 were Enterobacterales, Acinetobacter species, and Pseudomonas aeruginosa respectively. In our study, the prevalence of multidrug-resistant, extensively drug-resistant, carbapenemase-producing, and carbapenem nonsusceptible gram-negative bacilli were 45.2%, 7.7%, 5.4%, and 15.4% respectively. Out of 429 isolates, 66 demonstrated reduced susceptibility to the antibiotics meropenem and imipenem. These isolates were tested for carbapenemase production of which 34.8% (23/66) were carbapenemase producers. Out of 23 carbapenemase positive gram-negative bacteria, ten (10) and thirteen (13) were metallo-beta-lactamase and serine carbapenemase respectively. Three of 13 serine carbapenemase positive organisms were Klebsiella pneumoniae carbapenemase. Conclusion This study revealed an alarming level of antimicrobial resistance (AMR), with a high prevalence of multidrug-resistant (MDR) and extremely drug-resistant, carbapenemase-producing gram-negative bacteria, particularly among intensive care unit patients at the health facility level. These findings point to a scenario in which clinical management of infected patients becomes increasingly difficult and necessitates the use of “last-resort” antimicrobials likely exacerbating the magnitude of the global AMR crisis. This mandates robust AMR monitoring and an infection prevention and control program.


2018 ◽  
Vol 4 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Bhuiyan Mohammad Mahtab Uddin ◽  
Md Abdullah Yusuf ◽  
Zubair Ahmed Ratan

The rapid spread and dissemination of the multidrug-resistant bacteria worldwide represents a major public health problem. The development of antibiotics decreased the mortality among the human and animals leading to a better life expectancy. But the injudicious use of antimicrobials and selection pressure the microbes have developed resistance which became more prominent during last few decades. With the evolution of Methicilin-resistant Staphylococcus aureus (MRSA), Hospital-acquired MRSA, Communityacquired MRSA and MDR TB (Multidrug resistant tuberculosis) challenge for the clinicians have increased to a greater extent. The global emergence and dissemination of acquired carbapenemases among gram negative bacteria are considered a major public health problem. Gram-negative bacteria, most notably Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii, are among the most important causes of serious hospital-acquired and community-onset bacterial infections in humans, and resistance to antimicrobial agents in these bacteria has become an increasingly relevant problem. Recent development in nanotechnology based drug delivery system may prove to be solution for combating these resistant bacteria. However policies and regulations for antibiotic use should be formulated to control the further development of resistance among the microbes.Bangladesh Journal of Infectious Diseases 2017;4(1):25-28


2018 ◽  
Vol 84 (18) ◽  
Author(s):  
Anou M. Somboro ◽  
John Osei Sekyere ◽  
Daniel G. Amoako ◽  
Sabiha Y. Essack ◽  
Linda A. Bester

ABSTRACTThe worldwide proliferation of life-threatening metallo-β-lactamase (MBL)-producing Gram-negative bacteria is a serious concern to public health. MBLs are compromising the therapeutic efficacies of β-lactams, particularly carbapenems, which are last-resort antibiotics indicated for various multidrug-resistant bacterial infections. Inhibition of enzymes mediating antibiotic resistance in bacteria is one of the major promising means for overcoming bacterial resistance. Compounds having potential MBL-inhibitory activity have been reported, but none are currently under clinical trials. The need for developing safe and efficient MBL inhibitors (MBLIs) is obvious, particularly with the continuous spread of MBLs worldwide. In this review, the emergence and escalation of MBLs in Gram-negative bacteria are discussed. The relationships between different class B β-lactamases identified up to 2017 are represented by a phylogenetic tree and summarized. In addition, approved and/or clinical-phase serine β-lactamase inhibitors are recapitulated to reflect the successful advances made in developing class A β-lactamase inhibitors. Reported MBLIs, their inhibitory properties, and their purported modes of inhibition are delineated. Insights into structural variations of MBLs and the challenges involved in developing potent MBLIs are also elucidated and discussed. Currently, natural products and MBL-resistant β-lactam analogues are the most promising agents that can become clinically efficient MBLIs. A deeper comprehension of the mechanisms of action and activity spectra of the various MBLs and their inhibitors will serve as a bedrock for further investigations that can result in clinically useful MBLIs to curb this global menace.


2021 ◽  
Author(s):  
Abera Abdeta ◽  
Adane Bitew ◽  
Surafel Fentaw ◽  
Estifanos Tsige ◽  
Dawit Assefa ◽  
...  

Background Multi-drug resistant, extremely drug-resistant, pan-drug resistant, carbapenem-resistant, and carbapenemase-producing gram-negative bacteria are becoming more common in health care settings and are posing a growing threat to public health. Objective The study was aimed to determine the magnitude of multi-drug resistant, extremely drug-resistant, carbapenem non-susceptible, and carbapenemase-producing gram-negative bacilli at Ethiopian Public Health Institute. Materials and methods Prospective cross-sectional study was conducted from June 30, 2019, to May 30, 2020, at the national reference laboratory of the Ethiopian Public Health Institute. Clinical samples were collected, inoculated, and incubated in accordance to standard protocol for each sample. Antimicrobial susceptibility testing was done using Kirby Bauer disk diffusion. Identification was done using the traditional biochemical method. Multidrug-resistant and extensively drug-resistant were classified using a standardized definition established by European Centers for Disease prevention and control and the United States Centers for Disease prevention and control experts. Carbapenemase production was confirmed by modified carbapenem inactivation and a simplified carbapenem inactivation method. Meropenem with EDTA was used to differentiate serine carbapenemase and Metallo β-lactamase. Results A total of 1337 clinical specimens were analyzed, of which 429-gram negative bacilli isolates were recovered. Out of 429 isolates 319, 74, and 36 were Enterobacterales, Acinetobacter species, and P. aeruginosa respectively. In our study, the prevalence of Multidrug-resistant, extensively drug-resistant, Carbapenemase-producing, and carbapenem non-susceptible Gram-negative bacilli were, 45.2%, 7.7%, 5.4%, and 15.4% respectively. Out of 66 isolates screened for Carbapenemase, 34.8% (23/66) were Carbapenemase enzyme producers. Ten out of twenty-three Carbapenemase-positive organisms were Metallo-beta-lactamase producers. Thirteen out of twenty-three isolates were serine carbapenemase producers. Three out of 13 serine Carbapenemase positive organisms were Klebsiella pneumoniae Carbapenemase. Conclusion The finding from this study revealed a high prevalence of Multidrug-resistant, extremely drug-resistant, carbapenemase-producing gram-negative bacteria, particularly among Intensive care unit patients at the health facility level, this necessitates a robust laboratory-based antimicrobial resistance monitoring and infection prevention and control program.


Antibiotics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 58 ◽  
Author(s):  
Marianna Criscuolo ◽  
Enrico Maria Trecarichi

Patients suffering from hematological malignancies are at high risk for severe infections, including in particular bloodstream infections, which represent one of the most frequent life-threatening complications for these patients, with reported mortality rates reaching 40%. Furthermore, a worrisome increase in antimicrobial resistance of Gram-negative bacteria (e.g., cephalosporin- and/or carbapenem-resistant Enterobacteriaceae and multidrug-resistant (MDR) Pseudomonas aeruginosa) involved in severe infectious complications among patients with hematological malignancies has been reported during the last years. The two novel combination of cephalosporins and β-lactamase inhibitors, ceftolozane/tazobactam and ceftazidime/avibactam, were recently approved for treatment of complicated intra-abdominal and urinary tract infections and nosocomial pneumonia and display activity against several MDR Gram-negative strains. Although not specifically approved for neutropenic and/or cancer patients, these drugs are used in this setting due to increasing rates of infections caused by MDR Gram-negative bacteria. The aim of this review is to describe the actual evidence from scientific literature about the “real-life” use of these two novel drugs in patients with hematological malignancies and infections caused by MDR Gram-negative bacteria.


Author(s):  
Mireia López-Siles ◽  
Andrés Corral-Lugo ◽  
Michael J McConnell

Abstract Antimicrobial resistance is a major threat to global public health. Vaccination is an effective approach for preventing bacterial infections, however it has not been successfully applied to infections caused by some of the most problematic multidrug resistant pathogens. In this review, the potential for vaccines to contribute to reducing the burden of disease of infections caused by multidrug resistant Gram negative bacteria is presented. Technical, logistical and societal hurdles that have limited successful vaccine development for these infections in the past are identified, and recent advances that can contribute to overcoming these challenges are assessed. A synthesis of vaccine technologies that have been employed in the development of vaccines for key multidrug resistant Gram negative bacteria is included, and emerging technologies that may contribute to future successes are discussed. Finally, a comprehensive review of vaccine development efforts over the last 40 years for three of the most worrisome multidrug resistant Gram negative pathogens, Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa is presented, with a focus on recent and ongoing studies. Finally, future directions for the vaccine development field are highlighted.


2017 ◽  
Vol 61 (1) ◽  
pp. 23-35 ◽  
Author(s):  
Shewli Mukerji ◽  
Mark O’Dea ◽  
Mary Barton ◽  
Roy Kirkwood ◽  
Terence Lee ◽  
...  

Gram-negative bacteria are known to cause severe infections in both humans and animals. Antimicrobial resistance (AMR) in Gram-negative bacteria is a major challenge in the treatment of clinical infections globally due to the propensity of these organisms to rapidly develop resistance against antimicrobials in use. In addition, Gram-negative bacteria possess highly efficient mechanisms through which the AMR can be disseminated between pathogenic and commensal bacteria of the same or different species. These unique traits of Gram-negative bacteria have resulted in evolution of Gram-negative bacterial strains demonstrating resistance to multiple classes of antimicrobials. The evergrowing resistance issue has not only resulted in limitation of treatment options but also led to increased treatment costs and mortality rates in humans and animals. With few or no new antimicrobials in production to combat severe life-threatening infections, AMR has been described as the one of the most severe, long-term threats to human health. Aside from overuse and misuse of antimicrobials in humans, another factor that has exacerbated the emergence of AMR in Gram-negative bacteria is the veterinary use of antimicrobials that belong to the same classes considered to be critically important for treating serious life-threatening infections in humans. Despite the fact that development of AMR dates back to before the introduction of antimicrobials, the recent surge in the resistance towards all available critically important antimicrobials has emerged as a major public health issue. This review thus focuses on discussing the development, transmission and public health impact of AMR in Gram-negative bacteria in animals.


2014 ◽  
Vol 70 (a1) ◽  
pp. C710-C710
Author(s):  
Lucile Moynie ◽  
Luana Ferrara ◽  
Antoni Tortajada ◽  
James Naismith

The emergence of multidrug-resistant Gram-negative bacteria such as P. aeruginosa has become a growing challenge for developing new drugs. One of the strategies recently used to improve the efficacy of the antibiotics is to increase their uptake by exploiting bacterial transport systems such as the siderophore-mediated iron acquisition system. BAL30072, a new monosulfactam conjugated to a siderophore moiety has been shown to have potent activity against many Gram-negative bacteria [1]. Several proteins affecting susceptibility to this antibiotic have been identified in Pseudomonas aeruginosa [2]. As part of the Translocation project (Innovative Medicines Initiative), we have undertaken structural studies of these proteins and have solved the three dimensional structures of two of these targets. The structure of PiuA, a TonB-dependent siderophore transporter involved in the uptake of siderophore antibiotics across the outer membrane [2,3] has been solved to a resolution of 1.9 Å. The structure of PiuC, an Fe(II)/α-ketoglutarate-dependent dioxygenase, has been solved to a resolution of 2.6 Å. The structural and biochemical studies of these proteins will help us to understand the mode of action of these novel antibiotics and subsequently help to design new drugs acting against multidrug-resistant bacteria.


2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Rishi H.-P. Dhillon ◽  
John Clark

Extended spectrumβ-lactamases (ESBLs) are enzymes produced by a variety of Gram negative bacteria which confer an increased resistance to commonly used antibiotics. They are a worrying global public health issue as infections caused by such enzyme-producing organisms are associated with a higher morbidity and mortality and greater fiscal burden. Coupled with increasing prevalence rates worldwide and an ever diminishing supply in the antibiotic armamentarium, these enzymes represent a clear and present danger to public health. This article aims to give an overview of the current situation regarding ESBLs, with a focus on the epidemiology and management of such infections.


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