scholarly journals Correlated Transcriptional Responses Provide Insights into the Synergy Mechanisms of the Furazolidone, Vancomycin, and Sodium Deoxycholate Triple Combination in Escherichia coli

mSphere ◽  
2021 ◽  
Author(s):  
Catrina Olivera ◽  
Murray P. Cox ◽  
Gareth J. Rowlands ◽  
Jasna Rakonjac

Synergistic antibiotic combinations are a promising alternative strategy for developing effective therapies for multidrug-resistant bacterial infections. The synergistic combination of the existing antibiotics nitrofurans and vancomycin with sodium deoxycholate shows promise in inhibiting and killing multidrug-resistant Gram-negative bacteria.

2021 ◽  
Author(s):  
Catrina Olivera ◽  
Murray P. Cox ◽  
Gareth J Rowlands ◽  
Jasna Rakonjac

Effective therapeutic options are urgently needed to tackle antibiotic resistance. Furazolidone (FZ), vancomycin (VAN), and sodium deoxycholate (DOC) show promise as their combination can synergistically inhibit the growth of, and kill, multidrug-resistant Gram-negative bacteria that are classified as critical priority by the World Health Organization. Here, we investigated the mechanisms of action and synergy of this drug combination using a transcriptomics approach in the model bacterium Escherichia coli. We show that FZ and DOC elicit highly similar gene perturbations indicative of iron starvation, decreased respiration and metabolism, and translational stress. In contrast, VAN induced envelope stress responses, in agreement with its known role in peptidoglycan synthesis inhibition. FZ induced the SOS response consistent with its DNA damaging effects, but we demonstrate that using FZ in combination with the other two compounds enables use of lower dosages and largely mitigates its mutagenic effects. Based on the gene expression changes identified, we propose a synergy mechanism where the combined effects of FZ, VAN, and DOC amplify damage to Gram-negative bacteria while simultaneously suppressing antibiotic resistance mechanisms.


2012 ◽  
Vol 40 (6) ◽  
pp. 1549-1552 ◽  
Author(s):  
Carla L. Brown ◽  
Karen Smith ◽  
Laura McCaughey ◽  
Daniel Walker

The emergence of pan-resistant strains of Gram-negative pathogens and the ability of many bacteria to form multidrug-resistant biofilms during chronic infection poses the grave threat of bacterial infections that are truly untreatable with our current armoury of antibiotics. Despite obvious clinical need, few new antibiotics have entered clinical practice in recent years. For ‘difficult to treat’ Gram-negative bacteria such as Pseudomonas aeruginosa and Escherichia coli, where the presence of outer membrane and multidrug-efflux pumps severely limit the effectiveness of whole classes of antibiotics, the need is particularly pressing. An alternative approach to antimicrobial treatment is to use the well-characterized species-specific colicin-like bacteriocins which are produced by a wide range of Gram-negative bacteria, including Pseudomonas aeruginosa and Escherichia coli. Our current work on colicin-like bacteriocins aims to determine whether these potent antimicrobial agents are effective at killing bacteria growing in the biofilm state and during infection.


Author(s):  
M. Y. Iliyasu ◽  
I. Mustapha ◽  
H. Yakubu ◽  
H. M. Shuaibu ◽  
A. F. Umar ◽  
...  

Background of Study: Many virulence determinants contribute to the pathogenicity of Gram negative bacteria, like Escherichia coli, which is the most common cause of many infections worldwide such as urinary tract infection (UTI), profuse diarrhoea and septicaemia. Aim: To determine the genotypic characteristics of adhesin-producing E. coli isolates from clinical specimens. Place and Duration of Study: Conducted at the Infectious diseases hospital Bayara, Bauchi state, Nigeria, between February to March, 2019. Methods: A total of twelve (12) Gram negative bacterial isolates were selected based on the ability to grow on Luria-Bertani (LB) agar medium containing 100 µg/ml ampicillin. The isolates were from urine, stool, and blood specimens. The isolates were screened for multidrug resistant pattern according to Kirby-Bauer disc diffusion method. Adhesion factors, Fimbrial adhesin (fimH) and Invasive plasmid adhesin (ipaH) was genotyped by conventional PCR and sequenced. Results: All the isolates were resistant to Ampicillin, Cephalothin, Erythromycin, Fusidic acid, Novobiocin and Oxacillin, but sensitive to Augmentin, Colistin sulphate and Imipenem. Presence of fimH and ipaH genes were observed in nine isolates that expressed strong relationship with. Multidrug resistance (MDR). The fimH was the most prevalent found in urine, stool and blood isolates. Most of the adhesion genes sequence (61.8%) in this study had significant alignment (95 to 100% homology) with E.coli genome in the NCBI database. Conclusion: This study revealed the role of adhesin as virulence markers in MDR Gram negative bacteria and FimH is one of the commonest gene in MDR E.coli pathotypes.


2015 ◽  
Vol 15 (2) ◽  
pp. 150-155 ◽  
Author(s):  
Naomi Ochieng' ◽  
Humphrey Okechi ◽  
Susan Ferson ◽  
A. Leland Albright

OBJECT Ventriculoperitoneal shunt (VPS) infections are a major cause of morbidity and mortality in patients with hydrocephalus. Most data about these infections come from the Western literature. Few data about infecting organisms in Africa are available, yet knowledge of these organisms is important for the prevention and treatment of infectious complications. The purpose of this study was to determine the organisms cultured from infected shunts in a rural Kenyan hospital. METHODS The authors conducted a retrospective study of patients with VPS infections recorded in the neurosurgical database of BethanyKids at Kijabe Hospital between September 2010 and July 2012. RESULTS Among 53 VPS infections confirmed by culture, 68% occurred in patients who were younger than 6 months. Seventy-nine percent of the infections occurred within 2 months after shunt insertion. Only 51% of infections were caused by Staphylococcus species (Staphylococcus aureus 25%, other Staphylococcus species 26%), whereas 40% were caused by gram-negative bacteria. All S. aureus infections and 79% of other Staphylococcus infections were sensitive to cefazolin, but only 1 of 21 gram-negative bacteria was sensitive to it. The majority of gram-negative bacterial infections were multidrug resistant, but 17 of the 20 gram-negative bacteria were sensitive to meropenem. Gram-negative bacterial infections were associated with worse outcomes. CONCLUSIONS The high proportion of gram-negative infections differs from data in the Western literature, in which Staphylococcus epidermidis is by far the most common organism. Once a patient is diagnosed with a VPS infection in Kenya, immediate treatment is recommended to cover both gram-positive and gram-negative bacterial infections. Data from other Sub-Saharan countries are needed to determine if those countries have the same increased frequency of gram-negative infections.


mBio ◽  
2018 ◽  
Vol 9 (4) ◽  
Author(s):  
Yingbo Shen ◽  
Zuowei Wu ◽  
Yang Wang ◽  
Rong Zhang ◽  
Hong-Wei Zhou ◽  
...  

ABSTRACTThe recent emergence of a transferable colistin resistance mechanism, MCR-1, has gained global attention because of its threat to clinical treatment of infections caused by multidrug-resistant Gram-negative bacteria. However, the possible transmission route ofmcr-1amongEnterobacteriaceaespecies in clinical settings is largely unknown. Here, we present a comprehensive genomic analysis ofEscherichia coliisolates collected in a hospital in Hangzhou, China. We found thatmcr-1-carrying isolates from clinical infections and feces of inpatients and healthy volunteers were genetically diverse and were not closely related phylogenetically, suggesting that clonal expansion is not involved in the spread ofmcr-1. Themcr-1gene was found on either chromosomes or plasmids, but in most of theE. coliisolates,mcr-1was carried on plasmids. The genetic context of the plasmids showed considerable diversity as evidenced by the different functional insertion sequence (IS) elements, toxin-antitoxin (TA) systems, heavy metal resistance determinants, and Rep proteins of broad-host-range plasmids. Additionally, the genomic analysis revealed nosocomial transmission ofmcr-1and the coexistence ofmcr-1with other genes encoding β-lactamases and fluoroquinolone resistance in theE. coliisolates. These findings indicate thatmcr-1is heterogeneously disseminated in both commensal and pathogenic strains ofE. coli, suggest the high flexibility of this gene in its association with diverse genetic backgrounds of the hosts, and provide new insights into the genome epidemiology ofmcr-1among hospital-associatedE. colistrains.IMPORTANCEColistin represents one of the very few available drugs for treating infections caused by extensively multidrug-resistant Gram-negative bacteria. The recently emergentmcr-1colistin resistance gene threatens the clinical utility of colistin and has gained global attention. Howmcr-1spreads in hospital settings remains unknown and was investigated by whole-genome sequencing ofmcr-1-carryingEscherichia coliin this study. The findings revealed extraordinary flexibility ofmcr-1in its spread among genetically diverseE. colihosts and plasmids, nosocomial transmission ofmcr-1-carryingE. coli, and the continuous emergence of novel Inc types of plasmids carryingmcr-1and newmcr-1variants. Additionally,mcr-1was found to be frequently associated with other genes encoding β-lactams and fluoroquinolone resistance. These findings provide important information on the transmission and epidemiology ofmcr-1and are of significant public health importance as the information is expected to facilitate the control of this significant antibiotic resistance threat.


mBio ◽  
2017 ◽  
Vol 8 (4) ◽  
Author(s):  
Nadine Lemaître ◽  
Xiaofei Liang ◽  
Javaria Najeeb ◽  
Chul-Jin Lee ◽  
Marie Titecat ◽  
...  

ABSTRACT The infectious diseases caused by multidrug-resistant bacteria pose serious threats to humankind. It has been suggested that an antibiotic targeting LpxC of the lipid A biosynthetic pathway in Gram-negative bacteria is a promising strategy for curing Gram-negative bacterial infections. However, experimental proof of this concept is lacking. Here, we describe our discovery and characterization of a biphenylacetylene-based inhibitor of LpxC, an essential enzyme in the biosynthesis of the lipid A component of the outer membrane of Gram-negative bacteria. The compound LPC-069 has no known adverse effects in mice and is effective in vitro against a broad panel of Gram-negative clinical isolates, including several multiresistant and extremely drug-resistant strains involved in nosocomial infections. Furthermore, LPC-069 is curative in a murine model of one of the most severe human diseases, bubonic plague, which is caused by the Gram-negative bacterium Yersinia pestis. Our results demonstrate the safety and efficacy of LpxC inhibitors as a new class of antibiotic against fatal infections caused by extremely virulent pathogens. The present findings also highlight the potential of LpxC inhibitors for clinical development as therapeutics for infections caused by multidrug-resistant bacteria. IMPORTANCE The rapid spread of antimicrobial resistance among Gram-negative bacilli highlights the urgent need for new antibiotics. Here, we describe a new class of antibiotics lacking cross-resistance with conventional antibiotics. The compounds inhibit LpxC, a key enzyme in the lipid A biosynthetic pathway in Gram-negative bacteria, and are active in vitro against a broad panel of clinical isolates of Gram-negative bacilli involved in nosocomial and community infections. The present study also constitutes the first demonstration of the curative treatment of bubonic plague by a novel, broad-spectrum antibiotic targeting LpxC. Hence, the data highlight the therapeutic potential of LpxC inhibitors against a wide variety of Gram-negative bacterial infections, including the most severe ones caused by Y. pestis and by multidrug-resistant and extensively drug-resistant carbapenemase-producing strains. IMPORTANCE The rapid spread of antimicrobial resistance among Gram-negative bacilli highlights the urgent need for new antibiotics. Here, we describe a new class of antibiotics lacking cross-resistance with conventional antibiotics. The compounds inhibit LpxC, a key enzyme in the lipid A biosynthetic pathway in Gram-negative bacteria, and are active in vitro against a broad panel of clinical isolates of Gram-negative bacilli involved in nosocomial and community infections. The present study also constitutes the first demonstration of the curative treatment of bubonic plague by a novel, broad-spectrum antibiotic targeting LpxC. Hence, the data highlight the therapeutic potential of LpxC inhibitors against a wide variety of Gram-negative bacterial infections, including the most severe ones caused by Y. pestis and by multidrug-resistant and extensively drug-resistant carbapenemase-producing strains.


2020 ◽  
Vol 8 (5) ◽  
pp. 639 ◽  
Author(s):  
Alexis Simons ◽  
Kamel Alhanout ◽  
Raphaël E. Duval

Currently, the emergence and ongoing dissemination of antimicrobial resistance among bacteria are critical health and economic issue, leading to increased rates of morbidity and mortality related to bacterial infections. Research and development for new antimicrobial agents is currently needed to overcome this problem. Among the different approaches studied, bacteriocins seem to be a promising possibility. These molecules are peptides naturally synthesized by ribosomes, produced by both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), which will allow these bacteriocin producers to survive in highly competitive polymicrobial environment. Bacteriocins exhibit antimicrobial activity with variable spectrum depending on the peptide, which may target several bacteria. Already used in some areas such as agro-food, bacteriocins may be considered as interesting candidates for further development as antimicrobial agents used in health contexts, particularly considering the issue of antimicrobial resistance. The aim of this review is to present an updated global report on the biology of bacteriocins produced by GPB and GNB, as well as their antibacterial activity against relevant bacterial pathogens, and especially against multidrug-resistant bacteria.


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.


Author(s):  
Xiaoyu Lu ◽  
Xia Xiao ◽  
Yuan Liu ◽  
Ruichao Li ◽  
Zhiqiang Wang

Tigecycline and colistin are used as last-resort therapies to treat infections caused by multidrug-resistant (MDR) Gram-negative bacteria. However, the emergence of the plasmid-mediated tigecycline resistance gene tet (X4) and the plasmid-mediated colistin resistance gene mcr-1 represents a significant threat to human health.


2013 ◽  
Vol 58 (4) ◽  
pp. 1835-1846 ◽  
Author(s):  
Sarah M. Drawz ◽  
Krisztina M. Papp-Wallace ◽  
Robert A. Bonomo

ABSTRACTAs the incidence of Gram-negative bacterial infections for which few effective treatments remain increases, so does the contribution of drug-hydrolyzing β-lactamase enzymes to this serious clinical problem. This review highlights recent advances in β-lactamase inhibitors and focuses on agents with novel mechanisms of action against a wide range of enzymes. To this end, we review the β-lactamase inhibitors currently in clinical trials, select agents still in preclinical development, and older therapeutic approaches that are being revisited. Particular emphasis is placed on the activity of compounds at the forefront of the developmental pipeline, including the diazabicyclooctane inhibitors (avibactam and MK-7655) and the boronate RPX7009. With its novel reversible mechanism, avibactam stands to be the first new β-lactamase inhibitor brought into clinical use in the past 2 decades. Our discussion includes the importance of selecting the appropriate partner β-lactam and dosing regimens for these promising agents. This “renaissance” of β-lactamase inhibitors offers new hope in a world plagued by multidrug-resistant (MDR) Gram-negative bacteria.


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