scholarly journals Restoration of Bioactive Lantibiotic Suicin from a RemnantlanLocus of Pathogenic Streptococcus suis Serotype 2

2013 ◽  
Vol 80 (3) ◽  
pp. 1062-1071 ◽  
Author(s):  
Jian Wang ◽  
Yong Gao ◽  
Kunling Teng ◽  
Jie Zhang ◽  
Shutao Sun ◽  
...  
Keyword(s):  
Gene Promoter ◽  
Streptococcus Suis ◽  
Gene Clusters ◽  
Disulfide Bridge ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
System A ◽  
Bactericidal Activities

ABSTRACTLantibiotics are ribosomally synthesized, posttranslationally modified antimicrobial peptides. Their biosynthesis genes are usually organized in gene clusters, which are mainly found in Gram-positive bacteria, including pathogenic streptococci. Three highly virulentStreptococcus suisserotype 2 strains (98HAH33, 05ZYH33, and SC84) have been shown to contain an 89K pathogenicity island. Here, on these islands, we unveiled and reannotated a putative lantibiotic locus designatedsuiwhich contains a virulence-associated two-component regulator,suiK-suiR. In silicoanalysis revealed that the putative lantibiotic modification genesuiMwas interrupted by a 7.9-kb integron and that other biosynthesis-related genes contained various frameshift mutations. By reconstituting the intactsuiMinEscherichia colitogether with a semi-in vitrobiosynthesis system, a putative lantibiotic named suicin was produced with bactericidal activities against a variety of Gram-positive strains, including pathogenic streptococci and vancomycin-resistant enterococci. Ring topology dissection indicated that the 34-amino-acid lantibiotic contained two methyllanthionine residues and one disulfide bridge, which render suicin in an N-terminal linear and C-terminal globular shape. To confirm the function ofsuiK-suiR, SuiR was overexpressed and purified.In vitroanalysis showed that SuiR could specifically bind to thesuiAgene promoter. Its coexpression withsuiKcould activatesuiAgene promoter inLactococcus lactisNZ9000. Conclusively, we obtained a novel lantibiotic suicin by restoring its production from the remnantsuilocus and demonstrated that virulence-associated SuiK-SuiR regulates its production.

scholarly journals In Vitro Activity of Eravacycline against Gram-Positive Bacteria Isolated in Clinical Laboratories Worldwide from 2013 to 2017

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Ian Morrissey ◽  
Stephen Hawser ◽  
Sibylle H. Lob ◽  
James A. Karlowsky ◽  
Matteo Bassetti ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Microdilution Method ◽  
Clinical Laboratories ◽  
Broth Microdilution Method ◽  
Doubling Dilution

ABSTRACT Eravacycline is a novel, fully synthetic fluorocycline antibiotic being developed for the treatment of serious infections, including those caused by resistant Gram-positive pathogens. Here, we evaluated the in vitro activities of eravacycline and comparator antimicrobial agents against a recent global collection of frequently encountered clinical isolates of Gram-positive bacteria. The CLSI broth microdilution method was used to determine in vitro MIC data for isolates of Enterococcus spp. (n = 2,807), Staphylococcus spp. (n = 4,331), and Streptococcus spp. (n = 3,373) isolated primarily from respiratory, intra-abdominal, urinary, and skin specimens by clinical laboratories in 37 countries on three continents from 2013 to 2017. Susceptibilities were interpreted using both CLSI and EUCAST breakpoints. There were no substantive differences (a >1-doubling-dilution increase or decrease) in eravacycline MIC90 values for different species/organism groups over time or by region. Eravacycline showed MIC50 and MIC90 results of 0.06 and 0.12 μg/ml, respectively, when tested against Staphylococcus aureus, regardless of methicillin susceptibility. The MIC90 values of eravacycline for Staphylococcus epidermidis and Staphylococcus haemolyticus were equal (0.5 μg/ml). The eravacycline MIC90s for Enterococcus faecalis and Enterococcus faecium were 0.06 μg/ml and were within 1 doubling dilution regardless of the vancomycin susceptibility profile. Eravacycline exhibited MIC90 results of ≤0.06 μg/ml when tested against Streptococcus pneumoniae and beta-hemolytic and viridans group streptococcal isolates. In this surveillance study, eravacycline demonstrated potent in vitro activity against frequently isolated clinical isolates of Gram-positive bacteria (Enterococcus, Staphylococcus, and Streptococcus spp.), including isolates collected over a 5-year period (2013 to 2017), underscoring its potential benefit in the treatment of infections caused by common Gram-positive pathogens.

scholarly journals Mutations of the Listeria monocytogenes PeptidoglycanN-Deacetylase andO-Acetylase Result in Enhanced Lysozyme Sensitivity, Bacteriolysis, and Hyperinduction of Innate Immune Pathways

2011 ◽  
Vol 79 (9) ◽  
pp. 3596-3606 ◽  
Author(s):  
Chris S. Rae ◽  
Aimee Geissler ◽  
Paul C. Adamson ◽  
Daniel A. Portnoy
Keyword(s):  
Listeria Monocytogenes ◽  
Transcriptional Responses ◽  
Gram Positive ◽  
Content Type ◽  
Growth Defects ◽  
Gram Positive Bacteria ◽  
Host Cell Death

ABSTRACTListeria monocytogenesis a Gram-positive intracellular pathogen that is naturally resistant to lysozyme. Recently, it was shown that peptidoglycan modification by N-deacetylation or O-acetylation confers resistance to lysozyme in various Gram-positive bacteria, includingL. monocytogenes.L. monocytogenespeptidoglycan is deacetylated by the action ofN-acetylglucosamine deacetylase (Pgd) and acetylated byO-acetylmuramic acid transferase (Oat). We characterized Pgd−, Oat−, and double mutants to determine the specific role ofL. monocytogenespeptidoglycan acetylation in conferring lysozyme sensitivity during infection of macrophages and mice. Pgd−and Pgd−Oat−double mutants were attenuated approximately 2 and 3.5 logs, respectively,in vivo. In bone-marrow derived macrophages, the mutants demonstrated intracellular growth defects and increased induction of cytokine transcriptional responses that emanated from a phagosome and the cytosol. Lysozyme-sensitive mutants underwent bacteriolysis in the macrophage cytosol, resulting in AIM2-dependent pyroptosis. Each of thein vitrophenotypes was rescued upon infection of LysM−macrophages. The addition of extracellular lysozyme to LysM−macrophages restored cytokine induction, host cell death, andL. monocytogenesgrowth inhibition. This surprising observation suggests that extracellular lysozyme can access the macrophage cytosol and act on intracellular lysozyme-sensitive bacteria.

scholarly journals Combination of Pantothenamides with Vanin Inhibitors as a Novel Antibiotic Strategy against Gram-Positive Bacteria

2013 ◽  
Vol 57 (10) ◽  
pp. 4794-4800 ◽  
Author(s):  
Patrick A. M. Jansen ◽  
Pedro H. H. Hermkens ◽  
Patrick L. J. M. Zeeuwen ◽  
Peter N. M. Botman ◽  
Richard H. Blaauw ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Acid Synthesis ◽  
Spectrometric Analysis ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
New Compounds ◽  
Emergence Of Resistance ◽  
Hydrolysis Of

ABSTRACTThe emergence of resistance against current antibiotics calls for the development of new compounds to treat infectious diseases. Synthetic pantothenamides are pantothenate analogs that possess broad-spectrum antibacterial activityin vitroin minimal media. Pantothenamides were shown to be substrates of the bacterial coenzyme A (CoA) biosynthetic pathway, causing cellular CoA depletion and interference with fatty acid synthesis. In spite of their potential use and selectivity for bacterial metabolic routes, these compounds have never made it to the clinic. In the present study, we show that pantothenamides are not active as antibiotics in the presence of serum, and we found that they were hydrolyzed by ubiquitous pantetheinases of the vanin family. To address this further, we synthesized a series of pantetheinase inhibitors based on a pantothenate scaffold that inhibited serum pantetheinase activity in the nanomolar range. Mass spectrometric analysis showed that addition of these pantetheinase inhibitors prevented hydrolysis of pantothenamides by serum. We found that combinations of these novel pantetheinase inhibitors and prototypic pantothenamides like N5-Pan and N7-Pan exerted antimicrobial activityin vitro, particularly against Gram-positive bacteria (Staphylococcus aureus,Staphylococcus epidermidis,Streptococcus pneumoniae, andStreptococcus pyogenes) even in the presence of serum. These results indicate that pantothenamides, when protected against degradation by host pantetheinases, are potentially useful antimicrobial agents.

scholarly journals Discovery of Gene Cluster for Mycosporine-Like Amino Acid Biosynthesis from Actinomycetales Microorganisms and Production of a Novel Mycosporine-Like Amino Acid by Heterologous Expression

2014 ◽  
Vol 80 (16) ◽  
pp. 5028-5036 ◽  
Author(s):  
Kiyoko T. Miyamoto ◽  
Mamoru Komatsu ◽  
Haruo Ikeda
Keyword(s):  
Amino Acid ◽  
Gene Cluster ◽  
Gene Clusters ◽  
Biosynthetic Gene Cluster ◽  
Dependent Manner ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria

ABSTRACTMycosporines and mycosporine-like amino acids (MAAs), including shinorine (mycosporine-glycine-serine) and porphyra-334 (mycosporine-glycine-threonine), are UV-absorbing compounds produced by cyanobacteria, fungi, and marine micro- and macroalgae. These MAAs have the ability to protect these organisms from damage by environmental UV radiation. Although no reports have described the production of MAAs and the corresponding genes involved in MAA biosynthesis from Gram-positive bacteria to date, genome mining of the Gram-positive bacterial database revealed that two microorganisms belonging to the orderActinomycetales,Actinosynnema mirumDSM 43827 andPseudonocardiasp. strain P1, possess a gene cluster homologous to the biosynthetic gene clusters identified from cyanobacteria. When the two strains were grown in liquid culture,Pseudonocardiasp. accumulated a very small amount of MAA-like compound in a medium-dependent manner, whereasA. mirumdid not produce MAAs under any culture conditions, indicating that the biosynthetic gene cluster ofA. mirumwas in a cryptic state in this microorganism. In order to characterize these biosynthetic gene clusters, each biosynthetic gene cluster was heterologously expressed in an engineered host,Streptomyces avermitilisSUKA22. Since the resultant transformants carrying the entire biosynthetic gene cluster controlled by an alternative promoter produced mainly shinorine, this is the first confirmation of a biosynthetic gene cluster for MAA from Gram-positive bacteria. Furthermore,S. avermitilisSUKA22 transformants carrying the biosynthetic gene cluster for MAA ofA. mirumaccumulated not only shinorine and porphyra-334 but also a novel MAA. Structure elucidation revealed that the novel MAA is mycosporine-glycine-alanine, which substitutesl-alanine for thel-serine of shinorine.

scholarly journals Structure-Activity Relationship of the Aminomethylcyclines and the Discovery of Omadacycline

2015 ◽  
Vol 59 (11) ◽  
pp. 7044-7053 ◽  
Author(s):  
Laura Honeyman ◽  
Mohamed Ismail ◽  
Mark L. Nelson ◽  
Beena Bhatia ◽  
Todd E. Bowser ◽  
...  
Keyword(s):  
Tetracycline Resistance ◽  
Resistance Mechanisms ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
New Antibiotics ◽  
Protection Mechanisms ◽  
Relationship Of ◽  
Ribosomal Protection

ABSTRACTA series of novel tetracycline derivatives were synthesized with the goal of creating new antibiotics that would be unaffected by the known tetracycline resistance mechanisms. New C-9-position derivatives of minocycline (the aminomethylcyclines [AMCs]) were tested forin vitroactivity against Gram-positive strains containing known tetracycline resistance mechanisms of ribosomal protection (Tet M inStaphylococcus aureus,Enterococcus faecalis, andStreptococcus pneumoniae) and efflux (Tet K inS. aureusand Tet L inE. faecalis). A number of aminomethylcyclines with potentin vitroactivity (MIC range of ≤0.06 to 2.0 μg/ml) were identified. These novel tetracyclines were more active against one or more of the resistant strains than the reference antibiotics tested (MIC range, 16 to 64 μg/ml). The AMC derivatives were active against bacteria resistant to tetracycline by both efflux and ribosomal protection mechanisms. This study identified the AMCs as a novel class of antibiotics evolved from tetracycline that exhibit potent activityin vitroagainst tetracycline-resistant Gram-positive bacteria, including pathogenic strains of methicillin-resistantS. aureus(MRSA) and vancomycin-resistant enterococci (VRE). One derivative, 9-neopentylaminomethylminocycline (generic name omadacycline), was identified and is currently in human trials for acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP).

scholarly journals DhhP, a Cyclic di-AMP Phosphodiesterase of Borrelia burgdorferi, Is Essential for Cell Growth and Virulence

2014 ◽  
Vol 82 (5) ◽  
pp. 1840-1849 ◽  
Author(s):  
Meiping Ye ◽  
Jun-Jie Zhang ◽  
Xin Fang ◽  
Gavin B. Lawlis ◽  
Bryan Troxell ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Wild Type Strain ◽  
Wall Structure ◽  
Mammalian Host ◽  
Dependent Manner ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria

ABSTRACTCyclic di-AMP (c-di-AMP) is a recently discovered second messenger in bacteria. Most of work on c-di-AMP signaling has been done in Gram-positive bacteria, firmicutes, and actinobacteria, where c-di-AMP signaling pathways affect potassium transport, cell wall structure, and antibiotic resistance. Little is known about c-di-AMP signaling in other bacteria.Borrelia burgdorferi, the causative agent of Lyme disease, is a spirochete that has a Gram-negative dual membrane. In this study, we demonstrated thatB. burgdorferiBB0619, aDHH-DHHA1 domainprotein (herein designated DhhP), functions as c-di-AMP phosphodiesterase. Recombinant DhhP hydrolyzed c-di-AMP to pApA in a Mn2+- or Mg2+-dependent manner. In contrast to c-di-AMP phosphodiesterases reported thus far, DhhP appears to be essential forB. burgdorferigrowth bothin vitroand in the mammalian host. Inactivation of the chromosomaldhhPgene could be achieved only in the presence of a plasmid-encoded inducibledhhPgene. The conditionaldhhPmutant had a dramatic increase in intracellular c-di-AMP level in comparison to the isogenic wild-type strain. Unlike what has been observed in Gram-positive bacteria, elevated cellular c-di-AMP inB. burgdorferidid not result in an increased resistance to β-lactamase antibiotics, suggesting that c-di-AMP's functions in spirochetes differ from those in Gram-positive bacteria. In addition, thedhhPmutant was defective in induction of the σSfactor, RpoS, and the RpoS-dependent outer membrane virulence factor OspC, which uncovers an important role of c-di-AMP inB. burgdorferivirulence.

scholarly journals Regulation of the Alkane Hydroxylase CYP153 Gene in a Gram-Positive Alkane-Degrading Bacterium, Dietzia sp. Strain DQ12-45-1b

2015 ◽  
Vol 82 (2) ◽  
pp. 608-619 ◽  
Author(s):  
Jie-Liang Liang ◽  
Jing-Hong JiangYang ◽  
Yong Nie ◽  
Xiao-Lei Wu
Keyword(s):  
Gene Cluster ◽  
Mutant Strain ◽  
Gene Transcription ◽  
Gene Promoter ◽  
Gene Clusters ◽  
Gram Positive ◽  
Content Type ◽  
Degrading Bacterium ◽  
Degrading Bacteria ◽  
Arac Family

ABSTRACTCYP153, one of the most common medium-chainn-alkane hydroxylases belonging to the cytochrome P450 superfamily, is widely expressed inn-alkane-degrading bacteria. CYP153 is also thought to cooperate with AlkB in degrading variousn-alkanes. However, the mechanisms regulating the expression of the protein remain largely unknown. In this paper, we studied CYP153 gene transcription regulation by the potential AraC family regulator (CypR) located upstream of the CYP153 gene cluster in a broad-spectrumn-alkane-degrading Gram-positive bacterium,Dietziasp. strain DQ12-45-1b. We first identified the transcriptional start site and the promoter of the CYP153 gene cluster. Sequence alignment of upstream regions of CYP153 gene clusters revealed high conservation in the −10 and −35 regions inActinobacteria. Further analysis of the β-galactosidase activity in the CYP153 gene promoter-lacZfusion cell indicated that the CYP153 gene promoter was induced byn-alkanes comprised of 8 to 14 carbon atoms, but not by derived decanol and decanic acid. Moreover, we constructed acypRmutant strain and found that the CYP153 gene promoter activities and CYP153 gene transcriptional levels in the mutant strain were depressed compared with those in the wild-type strain in the presence ofn-alkanes, suggesting that CypR served as an activator for the CYP153 gene promoter. By comparing CYP153 gene arrangements inActinobacteriaandProteobacteria, we found that the AraC family regulator is ubiquitously located upstream of the CYP153 gene, suggesting its universal regulatory role in CYP153 gene transcription. We further hypothesize that the observed mode of CYP153 gene regulation is shared by manyActinobacteria.

scholarly journals A Novel Dual-creMotif Enables Two-Way Autoregulation of CcpA inClostridium acetobutylicum

2018 ◽  
Vol 84 (8) ◽  
pp. e00114-18 ◽  
Author(s):  
Lu Zhang ◽  
Yanqiang Liu ◽  
Yunpeng Yang ◽  
Weihong Jiang ◽  
Yang Gu
Keyword(s):  
Regulatory Network ◽  
Target Genes ◽  
Protein A ◽  
Cell Physiology ◽  
Coding Region ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria

ABSTRACTThe master regulator CcpA (catabolite control protein A) manages a large and complex regulatory network that is essential for cellular physiology and metabolism in Gram-positive bacteria. Although CcpA can affect the expression of target genes by binding to acis-acting catabolite-responsive element (cre), whether and how the expression of CcpA is regulated remain poorly explored. Here, we report a novel dual-cremotif that is employed by the CcpA inClostridium acetobutylicum, a typical solventogenicClostridiumspecies, for autoregulation. Twocresites are involved in CcpA autoregulation, and they reside in the promoter and coding regions of CcpA. In this dual-cremotif,creP, in the promoter region, positively regulatesccpAtranscription, whereascreORF, in the coding region, negatively regulates this transcription, thus enabling two-way autoregulation of CcpA. Although CcpA boundcrePmore strongly thancreORFin vitro, thein vivoassay showed thatcreORF-based repression dominates CcpA autoregulation during the entire fermentation. Finally, a synonymous mutation ofcreORFwas made within the coding region, achieving an increased intracellular CcpA expression and improved cellular performance. This study provides new insights into the regulatory role of CcpA inC. acetobutylicumand, moreover, contributes a new engineering strategy for this industrial strain.IMPORTANCECcpA is known to be a key transcription factor in Gram-positive bacteria. However, it is still unclear whether and how the intracellular CcpA level is regulated, which may be essential for maintaining normal cell physiology and metabolism. We discovered here that CcpA employs a dual-cremotif to autoregulate, enabling dynamic control of its own expression level during the entire fermentation process. This finding answers the questions above and fills a void in our understanding of the regulatory network of CcpA. Interference in CcpA autoregulation leads to improved cellular performance, providing a new useful strategy in genetic engineering ofC. acetobutylicum. Since CcpA is widespread in Gram-positive bacteria, including pathogens, this dual-cre-based CcpA autoregulation would be valuable for increasing our understanding of CcpA-based global regulation in bacteria.

scholarly journals In Vitro and In Vivo Antibacterial Activities of DW-224a, a New Fluoronaphthyridone

2006 ◽  
Vol 50 (6) ◽  
pp. 2261-2264 ◽  
Author(s):  
Hee-Soo Park ◽  
Hyun-Joo Kim ◽  
Min-Jung Seol ◽  
Dong-Rack Choi ◽  
Eung-Chil Choi ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
The Other ◽  
Vitro Activity ◽  
Gram Negative Bacteria ◽  
In Vitro Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

ABSTRACT DW-224a showed the most potent in vitro activity among the quinolone compounds tested against clinical isolates of gram-positive bacteria. Against gram-negative bacteria, DW-224a was slightly less active than the other fluoroquinolones. The in vivo activities of DW-224a against gram-positive bacteria were more potent than those of other quinolones.

scholarly journals Low-Molecular-Weight Metabolites Secreted by Paenibacillus larvae as Potential Virulence Factors of American Foulbrood

2014 ◽  
Vol 80 (8) ◽  
pp. 2484-2492 ◽  
Author(s):  
Hedwig-Annabell Schild ◽  
Sebastian W. Fuchs ◽  
Helge B. Bode ◽  
Bernd Grünewald
Keyword(s):  
Molecular Weight ◽  
Virulence Factors ◽  
Gene Clusters ◽  
Paenibacillus Larvae ◽  
Economic Losses ◽  
Low Molecular Weight ◽  
American Foulbrood ◽  
Toxic Activity ◽  
Content Type

ABSTRACTThe spore-forming bacteriumPaenibacillus larvaecauses a severe and highly infective bee disease, American foulbrood (AFB). Despite the large economic losses induced by AFB, the virulence factors produced byP. larvaeare as yet unknown. To identify such virulence factors, we experimentally infected young, susceptible larvae of the honeybee,Apis mellifera carnica, with differentP. larvaeisolates. Honeybee larvae were rearedin vitroin 24-well plates in the laboratory after isolation from the brood comb. We identified genotype-specific differences in the etiopathology of AFB between the tested isolates ofP. larvae, which were revealed by differences in the median lethal times. Furthermore, we confirmed that extracts ofP. larvaecultures contain low-molecular-weight compounds, which are toxic to honeybee larvae. Our data indicate thatP. larvaesecretes metabolites into the medium with a potent honeybee toxic activity pointing to a novel pathogenic factor(s) ofP. larvae. Genome mining ofP. larvaesubsp.larvaeBRL-230010 led to the identification of several biosynthesis gene clusters putatively involved in natural product biosynthesis, highlighting the potential ofP. larvaeto produce such compounds.

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