Potential Tamoxifen Repurposing to Combat Infections by Multidrug-Resistant Gram-Negative Bacilli

The development of new strategic therapies for multidrug-resistant bacteria, like the use of non-antimicrobial approaches and/or drugs repurposed to be used as monotherapies or in combination with clinically relevant antibiotics, has become urgent. A therapeutic alternative for infections by multidrug-resistant Gram-negative bacilli (MDR-GNB) is immune system modulation to improve the infection clearance. We showed that immunocompetent mice pretreated with tamoxifen at 80 mg/kg/d for three days and infected with Acinetobacter baumannii, Pseudomonas aeruginosa, or Escherichia coli in peritoneal sepsis models showed reduced release of the monocyte chemotactic protein-1 (MCP-1) and its signaling pathway interleukin-18 (IL-18), and phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2). This reduction of MCP-1 induced the reduction of migration of inflammatory monocytes and neutrophils from the bone marrow to the blood. Indeed, pretreatment with tamoxifen in murine peritoneal sepsis models reduced the bacterial load in tissues and blood, and increased mice survival from 0% to 60–100%. Together, these data show that tamoxifen presents therapeutic efficacy against MDR A. baumannii, P. aeruginosa, and E. coli in experimental models of infection and may be a new candidate to be repurposed as a treatment for GNB infections.

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Ts2631 Endolysin from the Extremophilic Thermus scotoductus Bacteriophage vB_Tsc2631 as an Antimicrobial Agent against Gram-Negative Multidrug-Resistant Bacteria

Viruses ◽

10.3390/v11070657 ◽

2019 ◽

Vol 11 (7) ◽

pp. 657 ◽

Cited By ~ 9

Author(s):

Magdalena Plotka ◽

Malgorzata Kapusta ◽

Sebastian Dorawa ◽

Anna-Karina Kaczorowska ◽

Tadeusz Kaczorowski

Keyword(s):

Metal Ion ◽

Ethylenediaminetetraacetic Acid ◽

Bacterial Load ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Gram Negative ◽

Log Reduction ◽

Carbapenem Resistant ◽

Heat Stable ◽

Transmission Electron

Bacteria that thrive in extreme conditions and the bacteriophages that infect them are sources of valuable enzymes resistant to denaturation at high temperatures. Many of these heat-stable proteins are useful for biotechnological applications; nevertheless, none have been utilized as antibacterial agents. Here, we demonstrate the bactericidal potential of Ts2631 endolysin from the extremophilic bacteriophage vB_Tsc2631, which infects Thermus scotoductus, against the alarming multidrug-resistant clinical strains of Acinetobacter baumannii, Pseudomonas aeruginosa and pathogens from the Enterobacteriaceae family. A 2–3.7 log reduction in the bacterial load was observed in antibacterial tests against A. baumannii and P. aeruginosa after 1.5 h. The Ts2631 activity was further enhanced by ethylenediaminetetraacetic acid (EDTA), a metal ion chelator (4.2 log reduction in carbapenem-resistant A. baumannii) and, to a lesser extent, by malic acid and citric acid (2.9 and 3.3 log reductions, respectively). The EDTA/Ts2631 combination reduced all pathogens of the Enterobacteriaceae family, particularly multidrug-resistant Citrobacter braakii, to levels below the detection limit (>6 log); these results indicate that Ts2631 endolysin could be useful to combat Gram-negative pathogens. The investigation of A. baumannii cells treated with Ts2631 endolysin variants under transmission electron and fluorescence microscopy demonstrates that the intrinsic antibacterial activity of Ts2631 endolysin is dependent on the presence of its N-terminal tail.

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Repurposing of the Tamoxifen Metabolites to Combat Infections by Multidrug-Resistant Gram-Negative Bacilli

Antibiotics ◽

10.3390/antibiotics10030336 ◽

2021 ◽

Vol 10 (3) ◽

pp. 336

Author(s):

Andrea Miró-Canturri ◽

Rafael Ayerbe-Algaba ◽

Andrea Vila-Domínguez ◽

Manuel E. Jiménez-Mejías ◽

Jerónimo Pachón ◽

...

Keyword(s):

Outer Membrane Proteins ◽

Bacterial Load ◽

Drug Repurposing ◽

Multidrug Resistant ◽

E Coli ◽

Immune System Cell ◽

Tamoxifen Metabolites ◽

Potential Alternative ◽

Immunocompetent Mice ◽

Time Kill

The development of new strategic antimicrobial therapeutic approaches, such as drug repurposing, has become an urgent need. Previously, we reported that tamoxifen presents therapeutic efficacy against multidrug-resistant (MDR) Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli in experimental infection models by modulating innate immune system cell traffic. The main objective of this study was to analyze the activity of N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen, three major metabolites of tamoxifen, against these pathogens. We showed that immunosuppressed mice infected with A. baumannii, P. aeruginosa, or E. coli in peritoneal sepsis models and treated with tamoxifen at 80 mg/kg/d for three days still reduced the bacterial load in tissues and blood. Moreover, it increased mice survival to 66.7% (for A. baumannii and E. coli) and 16.7% (for P. aeruginosa) when compared with immunocompetent mice. Further, susceptibility and time-kill assays showed that N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen exhibited minimum inhibitory concentration of the 90% of the isolates (MIC90) values of 16 mg/L, and were bactericidal against clinical isolates of A. baumannii and E. coli. This antimicrobial activity of tamoxifen metabolites paralleled an increased membrane permeability of A. baumannii and E. coli without affecting their outer membrane proteins profiles. Together, these data showed that tamoxifen metabolites presented antibacterial activity against MDR A. baumannii and E. coli, and may be a potential alternative for the treatment of infections caused by these two pathogens.

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Multidrug-resistant bacteria isolated from surgical site of dogs, surgeon's hands and operating room in a veterinary teaching hospital in Brazil

10.21203/rs.3.rs-216652/v1 ◽

2021 ◽

Author(s):

Mareliza Possa de Menezes ◽

Mariana Borzi ◽

Mayara Ruaro ◽

Marita Cardozo ◽

Fernando Ávila ◽

...

Keyword(s):

Multidrug Resistant ◽

High Rate ◽

Resistant Bacteria ◽

Coagulase Negative Staphylococci ◽

Gram Negative ◽

Source Of Infection ◽

The One ◽

Clean Contaminated ◽

In The Beginning ◽

Coagulase Positive Staphylococci

Abstract The aim of this study was to evaluate the prevalence and antimicrobial resistance profile of Gram-positive cocci and Gram-negative bacilli isolated from the surgical environment. All samples were collected during the intraoperative period of clean/clean-contaminated (G1) and contaminated (G2) surgery. A total of 150 samples were collected from the surgical wound in the beginning (n = 30) and end (n = 30) of the procedure, surgeon’s hands before (n = 30) and after (n = 30) antisepsis and the surgical environment (n = 30). Forty-three isolates with morphological and biochemical characteristics of Staphylococcus spp. and 13 of Gram-negative bacilli were obtained. Coagulase-negative staphylococci (85.71% [18/21]), coagulase-positive staphylococci (9.52% [2/21]) and Pseudomonas spp. (47.52% [1/21]) in G1, and coagulase-negative staphylococci (40% [14/35]), coagulase-positive staphylococci (20% [7/35]), Proteus spp. (17.14% [6/35]), E. coli (8.57% [3/35]), Pseudomonas spp. (2.86% [1/35]) and Salmonella spp. (2.86 [1/35]) in G2 were more frequently isolated, and a high incidence of multidrug resistance was observed in coagulase-negative staphylococci (87.5% [28/32]), coagulase-positive staphylococci (100% [11/11]) and Gram-negative bacilli (76.92% [10/13]). Methicillin-resistant Staphylococcus spp. accounted for 83.72% (36/43) of the Staphylococcus strains. Gram-negative bacilli cefotaxime-resistance constituted 81.82% (9/11) and imipenem resistance constituted 53.85% (7/13). The high rate of resistance of commensal bacteria found in our study is worrying. Coagulase-negative staphylococci are community pathogens related to nosocomial infections in human and veterinary hospitals, their presence in healthy patients and in veterinary professionals represent an important source of infection in the one health context. Continuous surveillance and application of antimicrobial stewardship programs are essential in the fight against this threat.

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Sarconesin II, a New Antimicrobial Peptide Isolated from Sarconesiopsis magellanica Excretions and Secretions

Molecules ◽

10.3390/molecules24112077 ◽

2019 ◽

Vol 24 (11) ◽

pp. 2077 ◽

Cited By ~ 1

Author(s):

Andrea Díaz-Roa ◽

Abraham Espinoza-Culupú ◽

Orlando Torres-García ◽

Monamaris M. Borges ◽

Ivan N. Avino ◽

...

Keyword(s):

Micrococcus Luteus ◽

Multidrug Resistant ◽

Peptide Sequence ◽

Resistant Bacteria ◽

Gram Positive ◽

Antimicrobial Drugs ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Conserved Domain ◽

Health Institutions

Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. Sarconesiopsis magellanica blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs). This study aims to identify and characterize a new S. magellanica AMP. RP-HPLC was used to fractionate ES, using C18 columns, and their antimicrobial activity was evaluated. The peptide sequence of the fraction collected at 43.7 min was determined by mass spectrometry (MS). Fluorescence and electronic microscopy were used to evaluate the mechanism of action. Toxicity was tested on HeLa cells and human erythrocytes; physicochemical properties were evaluated. The molecule in the ES was characterized as sarconesin II and it showed activity against Gram-negative (Escherichia coli MG1655, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa PA14) and Gram-positive (Staphylococcus aureus ATCC 29213, Micrococcus luteus A270) bacteria. The lowest minimum inhibitory concentration obtained was 1.9 μM for M. luteus A270; the AMP had no toxicity in any cells tested here and its action in bacterial membrane and DNA was confirmed. Sarconesin II was documented as a conserved domain of the ATP synthase protein belonging to the Fli-1 superfamily. The data reported here indicated that peptides could be alternative therapeutic candidates for use in infections against Gram-negative and Gram-positive bacteria and eventually as a new resource of compounds for combating multidrug-resistant bacteria.

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A small-molecule inhibitor of BamA impervious to efflux and the outer membrane permeability barrier

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1912345116 ◽

2019 ◽

Vol 116 (43) ◽

pp. 21748-21757 ◽

Cited By ~ 23

Author(s):

Elizabeth M. Hart ◽

Angela M. Mitchell ◽

Anna Konovalova ◽

Marcin Grabowicz ◽

Jessica Sheng ◽

...

Keyword(s):

Outer Membrane ◽

Small Molecule ◽

Cytoplasmic Membrane ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Permeability Barrier ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Bam Complex ◽

Induced Aggregation

The development of new antimicrobial drugs is a priority to combat the increasing spread of multidrug-resistant bacteria. This development is especially problematic in gram-negative bacteria due to the outer membrane (OM) permeability barrier and multidrug efflux pumps. Therefore, we screened for compounds that target essential, nonredundant, surface-exposed processes in gram-negative bacteria. We identified a compound, MRL-494, that inhibits assembly of OM proteins (OMPs) by the β-barrel assembly machine (BAM complex). The BAM complex contains one essential surface-exposed protein, BamA. We constructed a bamA mutagenesis library, screened for resistance to MRL-494, and identified the mutation bamAE470K. BamAE470K restores OMP biogenesis in the presence of MRL-494. The mutant protein has both altered conformation and activity, suggesting it could either inhibit MRL-494 binding or allow BamA to function in the presence of MRL-494. By cellular thermal shift assay (CETSA), we determined that MRL-494 stabilizes BamA and BamAE470K from thermally induced aggregation, indicating direct or proximal binding to both BamA and BamAE470K. Thus, it is the altered activity of BamAE470K responsible for resistance to MRL-494. Strikingly, MRL-494 possesses a second mechanism of action that kills gram-positive organisms. In microbes lacking an OM, MRL-494 lethally disrupts the cytoplasmic membrane. We suggest that the compound cannot disrupt the cytoplasmic membrane of gram-negative bacteria because it cannot penetrate the OM. Instead, MRL-494 inhibits OMP biogenesis from outside the OM by targeting BamA. The identification of a small molecule that inhibits OMP biogenesis at the cell surface represents a distinct class of antibacterial agents.

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619. High Multidrug-Resistant due to TEM and CTX-M-1 Types of Extended-Spectrum β-Lactamase and blaNDM-1 Type Carbapenemase Genes among Clinical Isolates of Gram-Negative Bacilli in Asella, Central Ethiopia

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.687 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S288-S288

Author(s):

Tafese B Tufa ◽

Fuchs André ◽

Sileshi Abdissa ◽

Zewdu Hurissa ◽

Hans Martin Orth ◽

...

Keyword(s):

Resistance Genes ◽

Carbapenem Resistance ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Local Data ◽

Gram Negative ◽

Central Ethiopia ◽

Unfavorable Clinical Outcome ◽

Resistance Patterns ◽

Group 2

Abstract Background Acute infectious diseases and sepsis are among the leading causes of mortality in Ethiopia. The lack of local data concerning causative pathogens and resistance patterns results in suboptimal empirical treatment and unfavorable clinical outcome. The objective of this study was the characterization of bacterial pathogens in hospitalized patients with febrile infections in Central Ethiopia. Methods In total, 684 patients ≥1 year of age with fever admitted to the Asella Teaching Hospital from April 2016 to June 2018 were included. Blood and other appropriate clinical specimens were cultured. Susceptibility testing was performed using the Kirby–Bauer method and VITEK2. Confirmation of species identification and identification of resistance genes were conducted using MALDI-ToF and PCR at a microbiology laboratory in Düsseldorf, Germany. Results In total, 684 study participants were included; 54% were male and mean age was 26.7 years. Thus, the overall culture positivity rate was 7.5%. Of the 83 cultured organisms, 38(46%) were Gram-negative, 43(52%) Gram-positive, and 2(2%) Candida species. Among the 38 Gram-negative isolates, 16(42%) were E. coli, 15(39%) K. pneumoniae, and 4(11%) P. aeruginosa. Resistance against commonly used antibiotics for Gram-negative at the study site was: piperacillin/tazobactam 48%(13), ampicillin/sulbactam 93% (25), cefotaxime 89%(24), ceftazidime 74%(20), Cefipime 74%(20), meropenem 7%(2), amikacin 4% (1) and gentamicin 56%(15). Of 27 Gram-negative available for resistance-gene detection, blaNDM-1 was detected in one K. pneumoniae isolate and blaNDM-1 plus blaOXA-51 in A. baumannii. 81%(22/27) of the Gram-negative rods were confirmed to contain ESBL-genes as follows: TEM 17(77%), CTX-M-1-group 15(68%), SHV-6(27%) and CTX-M-9-group 2(9%). Among isolated S.aureus, 1(5%) was confirmed to be Methicillin-resistant S. aureus. Conclusion We found a high prevalence (81%) of ESBL-producing bacteria and 7.4% carbapenem resistance at the study site. More than half of Gram-negative isolates had two or more mobile resistance genes. These findings warrant the need for local national multidrug-resistant surveillance. Strengthening of antimicrobial stewardship programs is needed in order to face the threat of multidrug-resistant bacteria. Disclosures All authors: No reported disclosures.

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Reduction of Environmental Contamination With Multidrug-Resistant Bacteria by Copper-Alloy Coating of Surfaces in a Highly Endemic Setting

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2017.52 ◽

2017 ◽

Vol 38 (7) ◽

pp. 765-771 ◽

Cited By ~ 11

Author(s):

Maria Souli ◽

Anastasia Antoniadou ◽

Ioannis Katsarolis ◽

Irini Mavrou ◽

Elisabeth Paramythiotou ◽

...

Keyword(s):

Phase 1 ◽

Demographic Data ◽

Alloy Coating ◽

Multidrug Resistant ◽

Copper Coating ◽

University Hospital ◽

Resistant Bacteria ◽

Resistant Organism ◽

Gram Negative ◽

Coated Surfaces

OBJECTIVETo evaluate the efficacy of copper-coating in reducing environmental colonization in an intensive-care unit (ICU) with multidrug-resistant-organism (MDRO) endemicityDESIGNInterventional, comparative crossover trialSETTINGThe general ICU of Attikon University hospital in Athens, GreecePATIENTSThose admitted to ICU compartments A and B during the study periodMETHODSBefore any intervention (phase 1), the optimum sampling method using 2 nylon swabs was validated. In phase 2, 6 copper-coated beds (ie, with coated upper, lower, and side rails) and accessories (ie, coated side table, intravenous [i.v.] pole stands, side-cart handles, and manual antiseptic dispenser cover) were introduced as follows: During phase 2a (September 2011 to February 2012), coated items were placed next to noncoated ones (controls) in both compartments A and B; during phase 2b (May 2012 to January 2013), all copper-coated items were placed in compartment A, and all noncoated ones (controls) in compartment B. Patients were randomly assigned to available beds. Environmental samples were cultured quantitatively for clinically important bacteria. Clinical and demographic data were collected from medical records.RESULTSCopper coating significantly reduced the percentage of colonized surfaces (55.6% vs 72.5%; P<.0001), the percentage of surfaces colonized by MDR gram-negative bacteria (13.8% vs 22.7%; P=.003) or by enterococci (4% vs 17%; P=.014), the total bioburden (2,858 vs 7,631 cfu/100 cm2; P=.008), and the bioburden of gram-negative isolates, specifically (261 vs 1,266 cfu/100 cm2; P=.049). This effect was more pronounced when the ratio of coated surfaces around the patient was increased (phase 2b).CONCLUSIONSCopper-coated items in an ICU setting with endemic high antimicrobial resistance reduced environmental colonization by MDROs.Infect Control Hosp Epidemiol 2017;38:765–771

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Species Diversity of Environmental GIM-1-Producing Bacteria Collected during a Long-Term Outbreak

Applied and Environmental Microbiology ◽

10.1128/aem.00424-16 ◽

2016 ◽

Vol 82 (12) ◽

pp. 3605-3610 ◽

Cited By ~ 13

Author(s):

Andreas F. Wendel ◽

Sofija Ressina ◽

Susanne Kolbe-Busch ◽

Klaus Pfeffer ◽

Colin R. MacKenzie

Keyword(s):

Resistance Genes ◽

Multidrug Resistant ◽

Hospital Environment ◽

Resistant Bacteria ◽

Environmental Sampling ◽

Gram Negative Bacteria ◽

Multidrug Resistant Bacteria ◽

Gram Negative ◽

Content Type

ABSTRACTReports of outbreaks concerning carbapenemase-producing Gram-negative bacteria in which the main source of transmission is the hospital environment are increasing. This study describes the results of environmental sampling in a protracted polyspecies metallo-beta-lactamase GIM-1 outbreak driven by plasmids and bacterial clones ofEnterobacter cloacaeandPseudomonas aeruginosain a tertiary care center. Environmental sampling targeting wet locations (especially sinks) was carried out on a surgical intensive care unit and on a medical ward on several occasions in 2012 and 2013. We were able to demonstrate 43blaGIM-1-carrying bacteria (mainly nonfermenters but alsoEnterobacteriaceae) that were either related or unrelated to clinical strains in 30 sinks and one hair washbasin. GIM-1 was found in 12 different species, some of which are described here as carriers of GIM-1. Forty out of 43 bacteria displayed resistance to carbapenems and, in addition, to various non-beta-lactam antibiotics. Colistin resistance was observed in twoE. cloacaeisolates with MICs above 256 mg/liter. TheblaGIM-1gene was harbored in 12 different class 1 integrons, some without the typical 3′ end. TheblaGIM-1gene was localized on plasmids in five isolates.In vitroplasmid transfer by conjugation was successful in one isolate. The environment, with putatively multispecies biofilms, seems to be an important biological niche for multidrug-resistant bacteria and resistance genes. Biofilms may serve as a “melting pot” for horizontal gene transfer, for dissemination into new species, and as a reservoir to propagate future hospital outbreaks.IMPORTANCEIn Gram-negative bacteria, resistance to the clinically relevant broad-spectrum carbapenem antibiotics is a major public health concern. Major reservoirs for these resistant organisms are not only the gastrointestinal tracts of animals and humans but also the (hospital) environment. Due to the difficulty in eradicating biofilm formation in the latter, a sustained dissemination of multidrug-resistant bacteria from the environment can occur. In addition, horizontal transfer of resistance genes on mobile genetic elements within biofilms adds to the total “resistance gene pool” in the environment. To gain insight into the transmission pathways of a rare and locally restricted carbapenemases resistance gene (blaGIM-1), we analyzed the genetic background of theblaGIM-1gene in environmental bacteria during a long-term polyspecies outbreak in a German hospital.

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Increasing frequency of gram-positive cocci and gram-negative multidrug-resistant bacteria in spontaneous bacterial peritonitis

Liver International ◽

10.1111/liv.12152 ◽

2013 ◽

Vol 33 (7) ◽

pp. 975-981 ◽

Cited By ~ 56

Author(s):

Alexandra Alexopoulou ◽

Nikolaos Papadopoulos ◽

Dimitrios G. Eliopoulos ◽

Apostolia Alexaki ◽

Athanasia Tsiriga ◽

...

Keyword(s):

Spontaneous Bacterial Peritonitis ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Multidrug Resistant Bacteria ◽

Gram Positive ◽

Gram Negative ◽

Bacterial Peritonitis ◽

Gram Positive Cocci

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Antibiotic Resistant Bacterial Isolates from Captive Green Turtles andIn VitroSensitivity to Bacteriophages

International Journal of Microbiology ◽

10.1155/2017/5798161 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

Alessandro Delli Paoli Carini ◽

Ellen Ariel ◽

Jacqueline Picard ◽

Lisa Elliott

Keyword(s):

Rapid Evolution ◽

Chelonia Mydas ◽

Multidrug Resistant ◽

Resistant Bacteria ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Green Turtles ◽

Resistant Genes ◽

Resistance Rates

This study aimed to test multidrug resistant isolates from hospitalised green turtles(Chelonia mydas)and their environment in North Queensland, Australia, forin vitrosusceptibility to bacteriophages. Seventy-one Gram-negative bacteria were isolated from green turtle eye swabs and water samples. Broth microdilution tests were used to determine antibiotic susceptibility. All isolates were resistant to at least two antibiotics, with 24% being resistant to seven of the eight antibiotics. Highest resistance rates were detected to enrofloxacin (77%) and ampicillin (69.2%). More than 50% resistance was also found to amoxicillin/clavulanic acid (62.5%), ceftiofur (53.8%), and erythromycin (53.3%). All the enriched phage filtrate mixtures resulted in the lysis of one or more of the multidrug resistant bacteria, includingVibrio harveyiandV. parahaemolyticus. These results indicate that antibiotic resistance is common in Gram-negative bacteria isolated from hospitalised sea turtles and their marine environment in North Queensland, supporting global concern over the rapid evolution of multidrug resistant genes in the environment. Using virulent bacteriophages as antibiotic alternatives would not only be beneficial to turtle health but also prevent further addition of multidrug resistant genes to coastal waters.

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