scholarly journals Structure of the enterococcal T4SS protein PrgL reveals unique dimerization interface in the VirB8 protein family

2020 ◽  
Author(s):  
Franziska Jäger ◽  
Anaïs Lamy ◽  
Nina Guerini ◽  
Wei-Sheng Sun ◽  
Ronnie P-A Berntsson
Keyword(s):  
Antibiotic Resistance Genes ◽  
Building Blocks ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Secretion Systems ◽  
Multidrug Resistant Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Dimerization Interface

AbstractMultidrug resistant bacteria are one of the most important current threats to public health and a serious problem in hospital acquired infections (HAIs). Most antibiotic resistance genes are acquired via conjugative gene transfer, in a process that is mediated by a protein machinery called the Type 4 Secretion System (T4SS). The core of the T4SS is a multiprotein complex that spans both the cell wall and cellular membrane(s), serving as a channel for macromolecular secretion. Although the majority of multidrug resistant bacteria responsible for HAIs are of Gram-positive origin, with Enterococci being major contributors, mostly Gram-negative T4SSs have been characterized. Here we describe the structure and organisation of PrgL, one of the seven membrane proteins forming the translocation channel of the T4SS encoded by the pCF10 plasmid from Enterococcus faecalis. We present the structure of the C-terminal domain of PrgL, which displays similarity to VirB8 proteins of Gram-negative secretion systems. PrgL forms dimers and higher order oligomers but does not interact strongly with the other T4SS components. In vitro experiments show that the soluble domain alone is enough to drive both dimerization and dodecamerisation, with a dimerization interface that differs from all other known VirB8-like proteins. Our findings provide insight into the molecular building blocks of Gram-positive T4SS, highlighting similarities but also unique features in PrgL compared to other VirB8-like proteins.

scholarly journals Inhibition of Multidrug-Resistant Gram-Positive and Gram-Negative Bacteria by a Photoactivated Porphyrin

2017 ◽  
Vol 66 (4) ◽  
pp. 533-536 ◽  
Author(s):  
Moreno Bondi ◽  
Anna Mazzini ◽  
Simona de Niederhäusern ◽  
Ramona Iseppi ◽  
Patrizia Messi
Keyword(s):  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
In Vitro Antibacterial Activity

The authors studied the in vitro antibacterial activity of the photo-activated porphyrin meso-tri(N-methyl-pyridyl), mono(N-tetradecyl-pyridyl)porphine (C14) against four multidrug-resistant bacteria: Staphylococcus aureus, Enterococcus faecalis (Gram-positive), Escherichia coli, Pseudomonas aeruginosa (Gram-negative). Using 10 μg/ml of porphyrin and 60 sec irradiation we observed the remarkable susceptibility of S. aureus and E. faecalis to treatment while, under the same conditions, E. coli and P. aeruginosa showed very low susceptibility. In a later stage, suspensions of Gram-negative bacteria were processed with EDTA before photo-activation, obtaining a significant decrease in viable counts. In view of the results, if the combination of low porphyrin concentrations and short irradiation times will be effective in vivo also, this approach could be a possible alternative to antibiotics, in particular against localized infections due to multidrug-resistant microorganisms.

scholarly journals In vitro activity of antimicrobial peptide CDP-B11 alone and in combination with colistin against colistin-resistant and multidrug-resistant Escherichia coli

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kaitlin S. Witherell ◽  
Jason Price ◽  
Ashok D. Bandaranayake ◽  
James Olson ◽  
Douglas R. Call
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Peptide ◽  
Membrane Integrity ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
E Coli ◽  
Minimal Media

AbstractMultidrug-resistant bacteria are a growing global concern, and with increasingly prevalent resistance to last line antibiotics such as colistin, it is imperative that alternative treatment options are identified. Herein we investigated the mechanism of action of a novel antimicrobial peptide (CDP-B11) and its effectiveness against multidrug-resistant bacteria including Escherichia coli #0346, which harbors multiple antibiotic-resistance genes, including mobilized colistin resistance gene (mcr-1). Bacterial membrane potential and membrane integrity assays, measured by flow cytometry, were used to test membrane disruption. Bacterial growth inhibition assays and time to kill assays measured the effectiveness of CDP-B11 alone and in combination with colistin against E. coli #0346 and other bacteria. Hemolysis assays were used to quantify the hemolytic effects of CDP-B11 alone and in combination with colistin. Findings show CDP-B11 disrupts the outer membrane of E. coli #0346. CDP-B11 with colistin inhibits the growth of E. coli #0346 at ≥ 10× lower colistin concentrations compared to colistin alone in Mueller–Hinton media and M9 media. Growth is significantly inhibited in other clinically relevant strains, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In rich media and minimal media, the drug combination kills bacteria at a lower colistin concentration (1.25 μg/mL) compared to colistin alone (2.5 μg/mL). In minimal media, the combination is bactericidal with killing accelerated by up to 2 h compared to colistin alone. Importantly, no significant red blood hemolysis is evident for CDP-B11 alone or in combination with colistin. The characteristics of CDP-B11 presented here indicate that it can be used as a potential monotherapy or as combination therapy with colistin for the treatment of multidrug-resistant infections, including colistin-resistant infections.

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

2013 ◽  
Vol 33 (7) ◽  
pp. 975-981 ◽  
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

scholarly journals Trends of Bloodstream Infections in a University Greek Hospital during a Three-Year Period: Incidence of Multidrug-Resistant Bacteria and Seasonality in Gram-negative Predominance

2017 ◽  
Vol 66 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Fevronia Kolonitsiou ◽  
Matthaios Papadimitriou-Olivgeris ◽  
Anastasia Spiliopoulou ◽  
Vasiliki Stamouli ◽  
Vasileios Papakostas ◽  
...  
Keyword(s):  
Bloodstream Infections ◽  
Multidrug Resistant ◽  
Blood Cultures ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Carbapenem Resistant

The aim of the study was to assess the epidemiology, the incidence of multidrug-resistant bacteria and bloodstream infections’ (BSIs) seasonality in a university hospital. This retrospective study was carried out in the University General Hospital of Patras, Greece, during 2011–13 y. Blood cultures from patients with clinical presentation suggestive of bloodstream infection were performed by the BacT/ALERT System. Isolates were identified by Vitek 2 Advanced Expert System. Antibiotic susceptibility testing was performed by the disk diffusion method and E-test. Resistance genes (mecA in staphylococci; vanA/vanB/vanC in enterococci; blaKPC/blaVIM/blaNDM in Klebsiella spp.) were detected by PCR. In total, 4607 (9.7%) blood cultures were positive from 47451 sets sent to Department of Microbiology, representing 1732 BSIs. Gram-negative bacteria (52.3%) were the most commonly isolated, followed by Gram-positive (39.5%), fungi (6.6%) and anaerobes bacteria (1.8%). The highest contamination rate was observed among Gram-positive bacteria (42.3%). Among 330 CNS and 150 Staphylococcus aureus, 281 (85.2%) and 60 (40.0%) were mecA-positive, respectively. From 113 enterococci, eight were vanA, two vanB and two vanC-positives. Of the total 207 carbapenem-resistant Klebsiella pneumoniae (73.4%), 202 carried blaKPC, four blaKPC and blaVIM and one blaVIM. A significant increase in monthly BSIs’ incidence was shown (R2: 0.449), which may be attributed to a rise of Gram-positive BSIs (R2: 0.337). Gram-positive BSIs were less frequent in spring (P < 0.001), summer (P < 0.001), and autumn (P < 0.001), as compared to winter months, while Gram-negative bacteria (P < 0.001) and fungi (P < 0.001) were more frequent in summer months. BSIs due to methicillin resistant S. aureus and carbapenem-resistant Gram-negative bacteria increased during the study period. The increasing incidence of BSIs can be attributed to an increase of Gram-positive BSI incidence, even though Gram-negative bacteria remained the predominant ones. Seasonality may play a role in the predominance of Gram-negative’s BSI.

scholarly journals Investigation of urban birds as source of β-lactamase-producing Gram-negative bacteria in Marseille city, France

2019 ◽  
Vol 61 (1) ◽  
Author(s):  
Edgarthe Priscilla Ngaiganam ◽  
Isabelle Pagnier ◽  
Wafaa Chaalal ◽  
Thongpan Leangapichart ◽  
Selma Chabou ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Urban Birds ◽  
Multidrug Resistant Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Stool Samples

Abstract Background We investigate here the presence of multidrug-resistant bacteria isolated from stool samples of yellow-legged gulls and chickens (n = 136) in urban parks and beaches of Marseille, France. Bacterial isolation was performed on selective media, including MacConkey agar with ceftriaxone and LBJMR medium. Antibiotic resistance genes, including extended-spectrum β-lactamases (ESBL) (i.e. blaCTX-M, blaTEM and blaSHV), carbapenemases (blaKPC, blaVIM, blaNDM, blaOXA-23, blaOXA-24, blaOXA-48 and blaOXA-58) and colistin resistance genes (mcr-1 to mcr-5) were screened by real-time PCR and standard PCR and sequenced when found. Results Of the 136 stools samples collected, seven ESBL-producing Gram-negative bacteria (BGN) and 12 colistin-resistant Enterobacteriaceae were isolated. Among them, five ESBL-producing Escherichia coli and eight colistin-resistant Hafnia alvei strains were identified. Four blaTEM-1 genes were detected in yellow-legged gulls and chickens. Three CTX-M-15 genes were detected in yellow-legged gulls and pigeons, and one CTX-M-1 in a yellow-legged gull. No mcr-1 to mcr-5 gene were detected in colistin-resistant isolates. Genotyping of E. coli strains revealed four different sequence types already described in humans and animals and one new sequence type. Conclusions Urban birds, which are believed to have no contact with antibiotics appear as potential source of ESBL genes. Our findings highlight the important role of urban birds in the proliferation of multidrug-resistant bacteria and also the possible zoonotic transmission of such bacteria from wild birds to humans.

scholarly journals In Vitro Antibacterial Activity of Propyl-Propane-Thiosulfinate and Propyl-Propane-Thiosulfonate Derived from Allium spp. against Gram-Negative and Gram-Positive Multidrug-Resistant Bacteria Isolated from Human Samples

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Antonio Sorlozano-Puerto ◽  
Maria Albertuz-Crespo ◽  
Isaac Lopez-Machado ◽  
Juan Jose Ariza-Romero ◽  
Alberto Baños-Arjona ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bactericidal Activity ◽  
Multidrug Resistant ◽  
Clinical Samples ◽  
Resistant Bacteria ◽  
Moderate Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Multiresistant Bacteria

Background. The aim of this study was to compare the in vitro antibacterial activity of two compounds derived from Alliaceae, PTS (propyl-propane-thiosulfinate), and PTSO (propyl-propane-thiosulfonate), with that of other antibiotics commonly used against bacteria isolated from humans. Materials and Methods. A total of 212 gram-negative bacilli and 267 gram-positive cocci isolated from human clinical samples and resistant to at least one group of antibiotics were selected. In order to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) to various antibiotics as well as PTS and PTSO, all isolates underwent broth microdilution assay. Results. PTS showed moderate activity against Enterobacteriaceae with MIC50 (and MBC50) and MIC90 (and MBC90) values of 256-512 mg/L, while PTSO showed greater activity with MIC50 and MIC90 values of 64-128 mg/L and MBC50 and MBC90 values of 128-512 mg/L. These data show the bactericidal activity of both compounds and indicate that PTSO was more active than PTS against this group of bacteria. Both compounds showed lower activity against P. aeruginosa (MIC50 = 1024 mg/L, MIC90 = 2048 mg/L, MBC50 = 2048 mg/L, and MBC90 = 2048 mg/L, for PTS; MIC50 = 512 mg/L, MIC90 = 1024 mg/L, MBC50 = 512 mg/L, and MBC90 = 2048 mg/L, for PTSO) compared to those obtained in others nonfermenting gram-negative bacilli (MIC50 = 128 mg/L, MIC90 = 512 mg/L, MBC50 = 128 mg/L, and MBC90 = 512 mg/L, for PTS; MIC50 = 64 mg/L, MIC90 = 256 mg/L, MBC50 = 64 mg/L, and MBC90 = 256 mg/L, for PTSO) and also indicate the bactericidal activity of both compounds against these groups of bacteria. Finally, the activity against S. aureus, E. faecalis, and S. agalactiae was higher than that observed against enterobacteria, especially in the case of PTSO (MIC50 = 8 mg/L, MIC90 = 8 mg/L, MBC50 = 32 mg/L, and MBC90 = 64 mg/L, in S. aureus; MIC50 = 4 mg/L, MIC90 = 8 mg/L, MBC50 = 8 mg/L, and MBC90 = 16 mg/L, in E. faecalis and S. agalactiae). Conclusion. PTS and PTSO have a significant broad spectrum antibacterial activity against multiresistant bacteria isolated from human clinical samples. Preliminary results in present work provide basic and useful information for development and potential use of these compounds in the treatment of human infections.

scholarly journals Bacteriological Profile of Tracheal Aspirates of the Patients Attending Neuro-hospital Nepal

2010 ◽  
Vol 4 ◽  
Author(s):  
Pratirodh Koirala ◽  
Dwij Raj Bhatta ◽  
Prakash Ghimire ◽  
Bharat Mani Pokhrel ◽  
Upendra Devkota
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Gram Negative Bacteria ◽  
Viridans Streptococci ◽  
Multidrug Resistant Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Tracheal Aspirates

The tracheostomized patients are colonized mostly by gram negative bacteria which lead to either tracheobronchitis or bronchopneumonia. This study was conducted to isolate and identify the potential pathogen causing post tracheostomy infection. A cross-sectional study was conducted during April 2008 to February 2009 based at Neuro Center, Kathmandu. Tracheal aspirates of 50 patients having fever more than 38°C were collected and analyzed for bacterial content. Out of the 50 cases, 45(90%) cases showed bacterial growth. Sixty-seven isolates were identified; with 20(44.4%) poly-microbial cases. Pseudomonas aeruginosa and enteric gram negative bacteria were predominant bacteria (n=27, 40.3%) followed by Staphylococcus aureus (n=7, 10.4%), other Gram negative bacteria (n=4, 5.9%) and Viridans Streptococci (n=2, 2.9%). Pseudomonas aeruginosa were most sensitive to the Amikacin (n=22, 81.4%) and Ciprofloxacin (n=19, 70.3%). All Pseudomonal isolates were resistant to the Cefotaxime. Enteric Gram Negative bacteria (EGNB) were most sensitive to Amikacin and Chloramphenicol (20, 74.0%) and all were resistant to Ampicillin and Cephalexin. All the gram positive bacteria isolated were sensitive to Vancomycin. Among the total isolates, 24 (88.8%) of Pseudomonas aeruginosa, 21 (66.6%) of enteric gram negative bacteria, and 5 (55.5%) of Gram positive bacteria were multidrug resistant (MDR). The study reported alarming condition of MDR in tracheal aspirates. So surveillance for source of multidrug resistant bacteria would be beneficial for intervention of infection related to it. Key words: Tracheal aspirates, polymicrobial growth, Multidrug resistant bacteria (MDR)10.3126/ijls.v4i0.3496International Journal of Life Sciences Vol.4 2010 pp.60-65

scholarly journals Comparison of methods to detect the in vitro activity of silver nanoparticles (AgNP) against multidrug resistant bacteria

2015 ◽  
Vol 13 (1) ◽  
Author(s):  
Emerson Danguy Cavassin ◽  
Luiz Francisco Poli de Figueiredo ◽  
José Pinhata Otoch ◽  
Marcelo Martins Seckler ◽  
Roberto Angelo de Oliveira ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Multidrug Resistant ◽  
Vitro Activity ◽  
Resistant Bacteria ◽  
Comparison Of Methods ◽  
In Vitro Activity ◽  
Multidrug Resistant Bacteria

scholarly journals Environmental Spread of New Delhi Metallo-β-Lactamase-1-Producing Multidrug-Resistant Bacteria in Dhaka, Bangladesh

2017 ◽  
Vol 83 (15) ◽  
Author(s):  
Mohammad Aminul Islam ◽  
Moydul Islam ◽  
Rashedul Hasan ◽  
M. Iqbal Hossain ◽  
Ashikun Nabi ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Tap Water ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
New Delhi ◽  
Multidrug Resistant Bacteria ◽  
Content Type ◽  
Wastewater Samples

ABSTRACT Resistance to carbapenem antibiotics through the production of New Delhi metallo-β-lactamase-1 (NDM-1) constitutes an emerging challenge in the treatment of bacterial infections. To monitor the possible source of the spread of these organisms in Dhaka, Bangladesh, we conducted a comparative analysis of wastewater samples from hospital-adjacent areas (HAR) and from community areas (COM), as well as public tap water samples, for the occurrence and characteristics of NDM-1-producing bacteria. Of 72 HAR samples tested, 51 (71%) samples were positive for NDM-1-producing bacteria, as evidenced by phenotypic tests and the presence of the bla NDM-1 gene, compared to 5 of 41 (12.1%) samples from COM samples (P < 0.001). All tap water samples were negative for NDM-1-producing bacteria. Klebsiella pneumoniae (44%) was the predominant bacterial species among bla NDM-1-positive isolates, followed by Escherichia coli (29%), Acinetobacter spp. (15%), and Enterobacter spp. (9%). These bacteria were also positive for one or more other antibiotic resistance genes, including bla CTX-M-1 (80%), bla CTX-M-15 (63%), bla TEM (76%), bla SHV (33%), bla CMY-2 (16%), bla OXA-48-like (2%), bla OXA-1 (53%), and bla OXA-47-like (60%) genes. Around 40% of the isolates contained a qnr gene, while 50% had 16S rRNA methylase genes. The majority of isolates hosted multiple plasmids, and plasmids of 30 to 50 MDa carrying bla NDM-1 were self-transmissible. Our results highlight a number of issues related to the characteristics and source of spread of multidrug-resistant bacteria as a potential public health threat. In view of the existing practice of discharging untreated liquid waste into the environment, hospitals in Dhaka city contribute to the potential dissemination of NDM-1-producing bacteria into the community. IMPORTANCE Infections caused by carbapenemase-producing Enterobacteriaceae are extremely difficult to manage due to their marked resistance to a wide range of antibiotics. NDM-1 is the most recently described carbapenemase, and the bla NDM-1 gene, which encodes NDM-1, is located on self-transmissible plasmids that also carry a considerable number of other antibiotic resistance genes. The present study shows a high prevalence of NDM-1-producing organisms in the wastewater samples from hospital-adjacent areas as a potential source for the spread of these organisms to community areas in Dhaka, Bangladesh. The study also examines the characteristics of the isolates and their potential to horizontally transmit the resistance determinants. The significance of our research is in identifying the mode of spread of multiple-antibiotic-resistant organisms, which will allow the development of containment measures, leading to broader impacts in reducing their spread to the community.

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