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1

The acetylproteome of Gram-positive model bacterium Bacillus subtilis.  

PubMed

N(?) -lysine acetylation, a reversible and highly regulated PTM, has been shown to occur in the model Gram-negative bacteria Escherichia coli and Salmonella enterica. Here, we extend this acetylproteome analysis to Bacillus subtilis, a model Gram-positive bacterium. Through anti-acetyllysine antibody-based immunoseparation of acetylpeptides followed by nano-HPLC/MS/MS analysis, we identified 332 unique lysine-acetylated sites on 185 proteins. These proteins are mainly involved in cellular housekeeping functions such as central metabolism and protein synthesis. Fifity-nine of the lysine-acetylated proteins showed homology with lysine-acetylated proteins previously identified in E. coli, suggesting that acetylated proteins are more conserved. Notably, acetylation was found at or near the active sites predicted by Prosite signature, including SdhA, RocA, Kbl, YwjH, and YfmT, indicating that lysine acetylation may affect their activities. In 2-amino-3-ketobutyrate CoA ligase Kbl, a class II aminotransferase, a lysine residue involved in pyridoxal phosphate attachment was found to be acetylated. This data set provides evidence for the generality of lysine acetylation in eubacteria and opens opportunities to explore the consequences of acetylation modification on the molecular physiology of B. subtilis. PMID:23468065

Kim, Dooil; Yu, Byung Jo; Kim, Jung Ae; Lee, Yong-Jik; Choi, Soo-Geun; Kang, Sunghyun; Pan, Jae-Gu

2013-05-01

2

Postantibiotic Effect of Ceftaroline against Gram-Positive Organisms?  

PubMed Central

The postantibiotic effects (PAEs), postantibiotic sub-MIC effects (PA-SMEs), and sub-MIC effects (SMEs) of ceftaroline, a novel injectable cephalosporin, were determined for 15 gram-positive organisms. The pneumococcal, staphylococcal, and enterococcal PAEs were 0.8 to 1.8 h, 0.7 to 2.2 h, and 0.2 to 1.1 h, respectively. The corresponding PA-SMEs (0.4 times the MIC) were 2.5 to 6.7 h, 2.9 to >0.0 h, and 7.9 to >10.3 h, respectively. The PA-SMEs were longer than the PAEs, suggesting that sub-MIC levels extend the PAE of ceftaroline against gram-positive cocci.

Pankuch, G. A.; Appelbaum, P. C.

2009-01-01

3

Polyhydroxyalkanoates in Gram-positive bacteria: insights from the genera Bacillus and Streptomyces  

Microsoft Academic Search

Gram-positive bacteria, notably Bacillus and Streptomyces, have been used extensively in industry. However, these microorganisms have not yet been exploited for the production of the biodegradable polymers, polyhydroxyalkanoates (PHAs). Although PHAs have many potential applications, the cost of production means that medical applications are currently the main area of use. Gram-negative bacteria, currently the only commercial source of PHAs, have

Sabeel P. Valappil; Aldo R. Boccaccini; Christopher Bucke; Ipsita Roy

2007-01-01

4

The complete genome sequence of the Gram-positive bacterium Bacillus subtilis  

Microsoft Academic Search

Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large

F. Kunst; N. Ogasawara; I. Moszer; A. M. Albertini; G. Alloni; V. Azevedo; M. G. Bertero; P. Bessières; A. Bolotin; S. Borchert; R. Borriss; L. Boursier; A. Brans; M. Braun; S. C. Brignell; S. Bron; S. Brouillet; C. V. Bruschi; B. Caldwell; V. Capuano; N. M. Carter; S.-K. Choi; J.-J. Codani; I. F. Connerton; N. J. Cummings; R. A. Daniel; F. Denizot; K. M. Devine; A. Düsterhöft; S. D. Ehrlich; P. T. Emmerson; K. D. Entian; J. Errington; C. Fabret; E. Ferrari; D. Foulger; C. Fritz; M. Fujita; Y. Fujita; S. Fuma; A. Galizzi; N. Galleron; S.-Y. Ghim; P. Glaser; A. Goffeau; E. J. Golightly; G. Grandi; G. Guiseppi; B. J. Guy; K. Haga; J. Haiech; C. R. Harwood; A. Hénaut; H. Hilbert; S. Holsappel; S. Hosono; M.-F. Hullo; M. Itaya; L. Jones; B. Joris; D. Karamata; Y. Kasahara; M. Klaerr-Blanchard; C. Klein; Y. Kobayashi; P. Koetter; G. Koningstein; S. Krogh; M. Kumano; K. Kurita; A. Lapidus; S. Lardinois; J. Lauber; V. Lazarevic; S.-M. Lee; A. Levine; H. Liu; S. Masuda; C. Mauël; C. Médigue; N. Medina; R. P. Mellado; M. Mizuno; D. Moestl; S. Nakai; M. Noback; D. Noone; M. O'Reilly; K. Ogawa; A. Ogiwara; B. Oudega; S.-H. Park; V. Parro; T. M. Pohl; D. Portetelle; S. Porwollik; A. M. Prescott; E. Presecan; P. Pujic; B. Purnelle; G. Rapoport; M. Rieger; S. Reynolds; C. Rivolta; E. Rocha; B. Roche; M. Rose; Y. Sadaie; T. Sato; E. Scanlan; S. Schleich; R. Schroeter; F. Scoffone; J. Sekiguchi; A. Sekowska; S. J. Seror; P. Serror; B.-S. Shin; B. Soldo; A. Sorokin; E. Tacconi; T. Takagi; H. Takahashi; K. Takemaru; M. Takeuchi; A. Tamakoshi; T. Tanaka; P. Terpstra; A. Tognoni; V. Tosato; S. Uchiyama; M. Vandenbol; F. Vannier; A. Vassarotti; A. Viari; R. Wambutt; E. Wedler; H. Wedler; T. Weitzenegger; P. Winters; A. Wipat; H. Yamamoto; K. Yamane; K. Yasumoto; K. Yata; K. Yoshida; H.-F. Yoshikawa; E. Zumstein; H. Yoshikawa; A. Danchin

1997-01-01

5

The complete genome sequence of the gram-positive bacterium Bacillus subtilis  

Microsoft Academic Search

Bacillus subtilis is the best-characterized member of the Gram-positive bacteria. Its genome of 4,214,810 base pairs comprises 4,100 protein-coding genes. Of these protein-coding genes, 53% are represented once, while a quarter of the genome corresponds to several gene families that have been greatly expanded by gene duplication, the largest family containing 77 putative ATP-binding transport proteins. In addition, a large

F. Kunst; N. Ogasawara; I. Moszer; A. M. Albertini; G. Alloni; V. Azevedo; M. G. Bertero; P. Bessières; A. Bolotin; S. Borchert; R. Borriss; L. Boursier; A. Brans; M. Braun; S. C. Brignell; S. Bron; S. Brouillet; C. V. Bruschi; B. Caldwell; V. Capuano; N. M. Carter; S.-K. Choi; J.-J. Codani; I. F. Connerton; A. Danchin

1997-01-01

6

Bacillus daliensis sp. nov., an alkaliphilic, Gram-positive bacterium isolated from a soda lake.  

PubMed

A Gram-positive, alkaliphilic bacterium, designated strain DLS13T, was isolated from Dali Lake in Inner Mongolia Autonomous Region, China. The isolate was able to grow at pH 7.5-11.0 (optimum at pH 9), in 0-8?% (w/v) NaCl (optimum at 2?%, w/v) and at 10-45 °C (optimum at 30 °C). Cells of the isolate were facultatively anaerobic, spore-forming rods with peritrichous flagella. The predominant isoprenoid quinone was MK-7 and its cell wall peptidoglycan contained meso-diaminopimelic acid. The major polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were anteiso-C15:0, anteiso-C17:0 and iso-C15:0. The genomic DNA G+C content of the isolate was 43.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain DLS13T was a member of the genus Bacillus and most closely related to Bacillus saliphilus DSM 15402T (96.9?% similarity). The DNA-DNA relatedness value between strain DLS13T and B. saliphilus DSM 15402T was 38.7±1.9?%. Comparative analysis of genotypic and phenotypic features indicated that strain DLS13T represents a novel species of the genus Bacillus, for which the name Bacillus daliensis sp. nov. is proposed; the type strain is DLS13T (=CGMCC 1.10369T=JCM 17097T=NBRC 107572T). PMID:21669916

Zhai, Lei; Liao, Tingting; Xue, Yanfen; Ma, Yanhe

2011-06-13

7

Native-valve endocarditis caused by Mycobacterium chelonae, misidentified as polymicrobial gram-positive bacillus infection.  

PubMed

Mycobacterium chelonae, a species of rapidly growing mycobacteria, may grow in routine blood culture media and stain as gram-positive bacilli, which may cause diagnostic confusion. A patient with native-valve endocarditis caused by M. chelonae, which was misidentified as various gram-positive bacilli, is presented. PMID:23053507

Takekoshi, Daisuke; Al-Heeti, Omar; Belvitch, Patrick; Schraufnagel, Dean E

2012-10-10

8

Studies on the O3-initiated disinfection from Gram-positive bacteria Bacillus subtilis in aquatic systems  

Microsoft Academic Search

The kinetics of inactivation of Gram-positive strain, Bacillus subtilis in aquatic systems was investigated as function ozone aeration duration under varied conditions. Oxygen flow was in situ enriched with ozone using ozoniser, with [O3] ranging from (0.3 – 9.8) × 10 moles per liter of oxygen. The inactivation kinetics of B. subtilis followed pseudo–first-order kinetics with respect to microbe, under

Favourite N. Zuma; S. B. Jonnalagadda

2010-01-01

9

Similarly Organized Lysogeny Modules in Temperate Siphoviridae from Low GC Content Gram-Positive Bacteria  

Microsoft Academic Search

Temperate Siphoviridae from an evolutionarily related branch of low GC content gram-positive bacteria share a common genetic organization of lysogeny-related genes and the predicted proteins are linked by many sequence similarities. Their compact lysogeny modules [integrase\\/1–2 orfs (phage exclusion? and metalloproteinase motif proteins)\\/cI-like repressor\\/cro-like repressor\\/antirepressor (optional)] differ clearly from that of ?-like and L5-like viruses, the two currently established genera

Sacha Lucchini; Frank Desiere; Harald Brüssow

1999-01-01

10

Organic solvent adaptation of Gram positive bacteria: applications and biotechnological potentials.  

PubMed

Organic-solvent-tolerant bacteria are considered extremophiles with different tolerance levels that change among species and strains, but also depend on the inherent toxicity of the solvent. Extensive studies to understand the mechanisms of organic solvent tolerance have been done in Gram-negative bacteria. On the contrary, the information on the solvent tolerance mechanisms in Gram-positive bacteria remains scarce. Possible shared mechanisms among Gram-(-) and Gram-(+) microorganisms include: energy-dependent active efflux pumps that export toxic organic solvents to the external medium; cis-to-trans isomerization of unsaturated membrane fatty acids and modifications in the membrane phospholipid headgroups; formation of vesicles loaded with toxic compounds; and changes in the biosynthesis rate of phospholipids to accelerate repair processes. However, additional physiological responses of Gram-(+) bacteria to organic solvents seem to be specific. The aim of the present work is to review the state of the art of responsible mechanisms for organic solvent tolerance in Gram-positive bacteria, and their industrial and environmental biotechnology potential. PMID:21504787

Torres, Sebastian; Pandey, Ashok; Castro, Guillermo R

2011-04-12

11

Bacillus subtilis YhaM, a Member of a New Family of 3?-to-5? Exonucleases in Gram-Positive Bacteria  

PubMed Central

A strain of Bacillus subtilis lacking two 3?-to-5? exoribonucleases, polynucleotide phosphorylase (PNPase) and RNase R, was used to purify another 3?-to-5? exoribonuclease, which is encoded by the yhaM gene. YhaM was active in the presence of Mn2+ (or Co2+), was inactive in the presence of Mg2+, and could also degrade single-stranded DNA. The half-life of bulk mRNA in a mutant lacking PNPase, RNase R, and YhaM was not significantly different from that of the wild type, suggesting the existence of additional activities that can participate in mRNA turnover. Sequence homologues of YhaM were found only in gram-positive organisms. The Staphylococcus aureus homologue, CBF1, which had been characterized as a double-stranded DNA binding protein involved in plasmid replication, was also shown to be an Mn2+-dependent exoribonuclease. YhaM protein has a C-terminal “HD domain,” found in metal-dependent phosphohydrolases. By structure modeling, it was shown that YhaM also contains an N-terminal “OB-fold,” present in many oligosaccharide- and oligonucleotide-binding proteins. The combination of these two domains is unique. Thus, YhaM and 10 related proteins from gram-positive organisms constitute a new exonuclease family.

Oussenko, Irina A.; Sanchez, Roberto; Bechhofer, David H.

2002-01-01

12

A Green Nonsulfur Bacterium, Dehalococcoides ethenogenes, with the LexA-binding sequence found in Gram-positive organisms  

SciTech Connect

Dehalococcoides ethenogenes is a member of the physiologically diverse division of green nonsulfur bacteria. Using a TBLASTN search, the D. ethenogenes lexA gene has been identified, cloned, and expressed and its protein has been purified. Mobility shift assays revealed that the D. ethenogenes LexA protein specifically binds to both its own promoter and that of the uvrA gene, but not to the recA promoter. Our results demonstrate that the D. ethenogenes LexA binding site is GAACNNNNGTTC, which is identical to that found in gram-positive bacteria. In agreement with this fact, the Bacillus subtilis DinR protein binds specifically to the D. ethenogenes LexA operator. This constitutes the first non-gram-positive bacterium exhibiting a LexA binding site identical to that of B. subtilis.

de Henestrosa, Antonio R. (Barcelona, University of); Cune, Jordi (Barcelona, University of); Erill, Ivan (Barcelona, University of); Magnuson, Jon K. (BATTELLE (PACIFIC NW LAB)); Barbe, Jordi (Barcelona, University of)

2002-12-01

13

Poreforming bacteriocins of Gram-positive bacteria and self-protection mechanisms of producer organisms  

Microsoft Academic Search

Proteinaceous antimicrobial compounds are produced by a diversity of species ranging from bacteria to humans. This review focuses on the mode of action of pore-forming bacteriocins produced by Gram-positive bacteria. The mechanism of action of specific immunity proteins, which protect the producer strains from the lethal action of their own products (producer self-protection), are also discussed.

Tjakko Abee

1995-01-01

14

High osmolarity improves the electro-transformation efficiency of the gram-positive bacteria Bacillus subtilis and Bacillus licheniformis  

Microsoft Academic Search

A high osmolarity electroporation method has been developed for the efficient transformation of Bacillus subtilis and B. licheniformis. The presence of high concentrations of the osmoticums, sorbitol and mannitol, in the electroporation, growth and recovery media resulted in an approximately 5000-fold increase in the transformation efficiency of B. subtilis, with a maximum value of 1.4×106 transformants per ?g DNA. The

Gang-Ping Xue; Jennifer S Johnson; Brian P Dalrymple

1999-01-01

15

A novel compound from the marine bacterium Bacillus pumilus S6-15 inhibits biofilm formation in Gram-positive and Gram-negative species  

Microsoft Academic Search

Biofilm formation is a critical problem in nosocomial infections and in the aquaculture industries and biofilms show high resistance to antibiotics. The aim of the present study was to reveal a novel anti-biofilm compound from marine bacteria against antibiotic resistant Gram-positive and Gram-negative biofilms. The bacterial extract (50 ?g ml) of S6-01 (Bacillus indicus = MTCC 5559) showed 80–90% biofilm inhibition against Escherichia

Chari Nithya; Muthu Gokila Devi; Shunmugiah Karutha Pandian

2011-01-01

16

GIL16, a New Gram-Positive Tectiviral Phage Related to the Bacillus thuringiensis GIL01 and the Bacillus cereus pBClin15 Elements  

PubMed Central

One of the most notable characteristics of Tectiviridae resides in their double-layer coats: the double-stranded DNA is located within a flexible lipoprotein vesicle covered by a rigid protein capsid. Despite their apparent rarity, tectiviruses have an extremely wide distribution compared to other phage groups. Members of this family have been found to infect gram-negative (PRD1 and relatives) as well as gram-positive (Bam35, GIL01, AP50, and ?NS11) hosts. Several reports have shown that tectiviruses infecting gram-negative bacteria are closely related, whereas no information is currently available on the genetic relationship among those infecting gram-positive bacteria. The present study reports the sequence of GIL16, a new isolate originating from Bacillus thuringiensis, and a genetic comparison of this isolate with the tectiviral bacteriophages Bam35 and GIL01, which originated from B. thuringiensis serovars Alesti and Israelensis, respectively. In contrast to PRD1 and its relatives, these are temperate bacteriophages existing as autonomous linear prophages within the host cell. Mutations in a particular motif in both the GIL01 and GIL16 phages are also shown to correlate with a switch to the lytic cycle. Interestingly, both bacterial viruses displayed narrow, yet slightly different, host spectrums. We also explore the hypothesis that pBClin15, a linear plasmid hosted by the Bacillus cereus reference strain ATCC 14579, is also a prophage. Sequencing of its inverted repeats at both extremities and a comparison with GIL01 and GIL16 emphasize its relationship to the Tectiviridae.

Verheust, Celine; Fornelos, Nadine; Mahillon, Jacques

2005-01-01

17

Spectrum of gram-positive bacteraemia and in vitro activities of daptomycin, linezolid and vancomycin against organisms isolated from cancer patients.  

PubMed

Gram-positive organisms are the predominant bacterial pathogens in cancer patients. A survey indicated that coagulase-negative staphylococci (CoNS) (29.5%), Staphylococcus aureus (18.0%), Enterococcus spp. (12.1%) and viridans group streptococci (VGS) (9.1%) are isolated most often. The rate of reduced susceptibility to vancomycin (minimum inhibitory concentration ?1.0 ?g/mL) was 100% for meticillin-susceptible S. aureus and 99% for meticillin-resistant S. aureus, and 100% for meticillin-susceptible CoNS and 98% for meticillin-resistant CoNS. More than 98% of these isolates were susceptible to daptomycin and linezolid. Daptomycin and linezolid had comparable in vitro activity to vancomycin against Bacillus spp., Corynebacterium spp., Rhodococcus spp., Micrococcus spp., Stomatococcus mucilaginosus and VGS. Both agents were active against the majority (95%) of vancomycin-resistant organisms, including vancomycin-resistant enterococci, Pediococcus spp. and Leuconostoc spp. These data suggest that daptomycin and linezolid have an adequate antimicrobial spectrum and potent in vitro activity against Gram-positive isolates from cancer patients and may be considered as alternatives to vancomycin for empirical or targeted therapy in this setting. PMID:23481658

Rolston, Kenneth V I; Kapadia, Mona; Tarrand, Jeffrey; Coyle, Elizabeth; Prince, Randall A

2013-03-06

18

Novel fastidious, partially Acid-fast, anaerobic gram-positive bacillus associated with abscess formation and recovered from multiple medical centers.  

PubMed

We report a novel anaerobe causing abscess in four patients at three hospitals. In the clinical specimen, bacilli were branching, Gram positive, and acid fast. The organism grew slowly and was not identified by 16S rRNA sequencing. Our findings support the description of a new genus and species of the suborder Corynebacterineae. PMID:24025902

Harrington, S M; Bell, M; Bernard, K; Lagacé-Wiens, P; Schuetz, A N; Hartman, B; McQuiston, J R; Wilson, D; Lasalvia, M; Ng, B; Richter, S; Taege, A

2013-09-11

19

Expanding the Use of a Fluorogenic Method to Determine Activity and Mode of Action of Bacillus thuringiensis Bacteriocins Against Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Previously we described a rapid fluorogenic method to measure the activity of five bacteriocins produced by Mexican strains of Bacillus thuringiensis against B. cereus 183. Here we standardize this method to efficiently determine the activity of bacteriocins against both Gram-positive and Gram-negative bacteria. It was determined that the crucial parameter required to obtain reproducible results was the number of cells used in the assay, that is, ~4?×?108?cell/mL and ~7?×?108?cell/mL, respectively, for target Gram-positive and Gram-negative bacteria. Comparative analyses of the fluorogenic and traditional well-diffusion assays showed correlation coefficients of 0.88 to 0.99 and 0.83 to 0.99, respectively, for Gram-positive and Gram-negative bacteria. The fluorogenic method demonstrated that the five bacteriocins of B. thuringiensis have bacteriolytic and bacteriostatic activities against all microorganisms tested, including clinically significant bacteria such as Listeria monocytogenes, Proteus vulgaris, and Shigella flexneri reported previously to be resistant to the antimicrobials as determined using the well-diffusion protocol. These results demonstrate that the fluorogenic assay is a more sensitive, reliable, and rapid method when compared with the well-diffusion method and can easily be adapted in screening protocols for bacteriocin production by other microorganisms.

de la Fuente-Salcido, Norma M.; Barboza-Corona, J. Eleazar; Espino Monzon, A. N.; Pacheco Cano, R. D.; Balagurusamy, N.; Bideshi, Dennis K.; Salcedo-Hernandez, Ruben

2012-01-01

20

Expression of the Bacillus subtilis sacB gene leads to sucrose sensitivity in the gram-positive bacterium Corynebacterium glutamicum but not in Streptomyces lividans.  

PubMed Central

The expression of the structural gene (sacB) encoding Bacillus subtilis levansucrase in two gram-positive soil bacteria, Corynebacterium glutamicum ATCC 13032 and Streptomyces lividans 1326, was investigated. sacB expression in the presence of sucrose is lethal to C. glutamicum but not to S. lividans. While S. lividans secretes levansucrase into the medium, we could show that the enzyme is retained by C. glutamicum cells. Our results imply that the sacB gene can be used as a positive selection system in coryneform bacteria.

Jager, W; Schafer, A; Puhler, A; Labes, G; Wohlleben, W

1992-01-01

21

Rapid Detection of Gram-Positive Organisms by Use of the Verigene Gram-Positive Blood Culture Nucleic Acid Test and the BacT/Alert Pediatric FAN System in a Multicenter Pediatric Evaluation.  

PubMed

Assays that expedite the reporting of organism identification and antibiotic susceptibility status in positive blood cultures can fast track interventions that improve clinical outcomes. We evaluated the Verigene Gram-positive blood culture nucleic acid test (BC-GP) in two pediatric hospitals. Positive BacT/Alert Pediatric FAN blood cultures with Gram-positive organisms were tested using the BC-GP in tandem with routine laboratory procedures. To test organisms underrepresented in the clinical blood culture evaluation, blood culture bottles were spiked with diluted organism suspensions at concentrations of 10 to 100 CFU per milliliter. A total of 249 Gram-positive bacterial isolates were recovered from 242 blood cultures. The BC-GP detected Staphylococcus aureus, methicillin-susceptible S. aureus, and methicillin-resistant S. aureus with sensitivities of 100%, 99%, and 100% and specificities of 100%, 100%, and 99.5%, respectively. The BC-GP detected Staphylococcus epidermidis, methicillin-susceptible S. epidermidis, and methicillin-resistant S. epidermidis with sensitivities of 95%, 80%, and 96%, respectively, and 100% specificity. The BC-GP correctly identified 14/15 cases of Enterococcus faecalis and Enterococcus faecium bacteremia and 9 cases of Streptococcus pneumoniae. It misidentified 5/15 clinical blood cultures with Streptococcus mitis/Streptococcus oralis and 1/3 blood cultures spiked with Streptococcus anginosus group as S. pneumoniae. The BC-GP detected a case of Streptococcus pyogenes bacteremia but failed to detect 2/3 clinical blood cultures with Streptococcus agalactiae. BC-GP's rapid accurate detection of Staphylococcus spp., E. faecium, and E. faecalis and its ability to ascertain mecA, vanA, and vanB status may expedite clinical decisions pertaining to optimal antibiotic use. False-positive S. pneumoniae results may warrant reporting of only "Streptococcus spp." when this organism is reported by the BC-GP. PMID:23966484

Sullivan, K V; Turner, N N; Roundtree, S S; Young, S; Brock-Haag, C A; Lacey, D; Abuzaid, S; Blecker-Shelly, D L; Doern, C D

2013-08-21

22

Gram-positive siderophore-shuttle with iron-exchange from Fe-siderophore to apo-siderophore by Bacillus cereus YxeB.  

PubMed

Small molecule iron-chelators, siderophores, are very important in facilitating the acquisition of Fe(III), an essential element for pathogenic bacteria. Many Gram-negative outer-membrane transporters and Gram-positive lipoprotein siderophore-binding proteins have been characterized, and the binding ability of outer-membrane transporters and siderophore-binding proteins for Fe-siderophores has been determined. However, there is little information regarding the binding ability of these proteins for apo-siderophores, the iron-free chelators. Here we report that Bacillus cereus YxeB facilitates iron-exchange from Fe-siderophore to apo-siderophore bound to the protein, the first Gram-positive siderophore-shuttle system. YxeB binds ferrioxamine B (FO, Fe-siderophore)/desferrioxamine B (DFO, apo-siderophore) in vitro. Disc-diffusion assays and growth assays using the yxeB mutant reveal that YxeB is responsible for importing the FO. Cr-DFO (a FO analog) is bound by YxeB in vitro and B. cereus imports or binds Cr-DFO in vivo. In vivo uptake assays using Cr-DFO and FO and growth assays using DFO and Cr-DFO show that B. cereus selectively imports and uses FO when DFO is present. Moreover, in vitro competition assays using Cr-DFO and FO clearly demonstrate that YxeB binds only FO, not Cr-DFO, when DFO is bound to the protein. Iron-exchange from FO to DFO bound to YxeB must occur when DFO is initially bound by YxeB. Because the metal exchange rate is generally first order in replacement ligand concentration, protein binding of the apo-siderophore acts to dramatically enhance the iron exchange rate, a key component of the Gram-positive siderophore-shuttle mechanism. PMID:23924612

Fukushima, Tatsuya; Allred, Benjamin E; Sia, Allyson K; Nichiporuk, Rita; Andersen, Ulla N; Raymond, Kenneth N

2013-08-07

23

The influence of secretory-protein charge on late stages of secretion from the Gram-positive bacterium Bacillus subtilis.  

PubMed Central

Following their secretion across the cytoplasmic membrane, processed secretory proteins of Bacillus subtilis must fold into their native conformation prior to translocation through the cell wall and release into the culture medium. The rate and efficiency of folding are critical in determining the yields of intact secretory proteins. The B. subtilis membrane is surrounded by a thick cell wall comprising a heteropolymeric matrix of peptidoglycan and anionic polymers. The latter confer a high density of negative charge on the wall, endowing it with ion-exchange properties, and secretory proteins destined for the culture medium must traverse the wall as the last stage in the export process. To determine the influence of charge on late stages in the secretion of proteins from this bacterium, we have used sequence data from two related alpha-amylases, to engineer the net charge of AmyL, an alpha-amylase from Bacillus licheniformis that is normally secreted efficiently from B. subtilis. While AmyL has a pI of 7.0, chimaeric enzymes with pI values of 5.0 and 10.0 were produced and characterized. Despite the engineered changes to their physico-chemical properties, the chimaeric enzymes retained many of the enzymic characteristics of AmyL. We show that the positively charged protein interacts with the cell wall in a manner that influences its secretion.

Stephenson, K; Jensen, C L; J?rgensen, S T; Lakey, J H; Harwood, C R

2000-01-01

24

The Phosphorus-containing Compounds of Gram-positive and Gram-negative Organisms in Relation to the Gram Staining Reaction  

Microsoft Academic Search

SUMMARY : The phosphorus-containing compounds of certain Gram-positive and Gram-negative organisms were estimated by a modification of the Schmidt & Thannhauser (1945) procedure. Another method (Mitchell & Moyle, 1950, 1951 a, b, 1954) in which pentosenucleic acid (PNA) was estimated from the optical absorption of the ' PNA fraction ' at 260 mp. was found to be inaccurate, because of

A. S. JONES; S. B. H. RIZVI; M. STACEY

1958-01-01

25

Susceptibility of Fibronectin to Degradation by Various Gram-Negative and Gram-Positive Oral Micro-Organisms.  

National Technical Information Service (NTIS)

The degradative effects on tritiated human plasma fibronectin (FN) of proteases associated with twenty-five Gram-negative (GN) and fifteen Gram-positive (GP) oral microbial isolates were examined. Ninety-two percent of the GN and 20% of the GP isolates de...

E. D. Pederson B. L. Lamberts I. L. Shklair

1988-01-01

26

Effect of Hematin on the Recovery of Bacillus Anthracis and Related Organisms.  

National Technical Information Service (NTIS)

Freshly prepared alkaline hematin inhibits the growth of many Gram-positive organisms, including Bacillus anthracis; Gram-negative organisms, however, are generally not inhibited. Work on a selective medium for isolating B. anthracis that does not contain...

R. F. Knisely

1964-01-01

27

Evaluation of a Microarray-Based Assay for Rapid Identification of Gram-Positive Organisms and Resistance Markers in Positive Blood Cultures  

PubMed Central

Rapid identification of pathogens directly from positive blood cultures can play a major role in reducing patient mortality rates. We evaluated the performance of the Verigene Gram-Positive Blood Culture (BC-GP) assay (Nanosphere Inc., Northbrook, IL) for detection of commonly isolated Gram-positive organisms as well as associated resistance markers from positive blood cultures. Positive blood cultures (VersaTREK; Trek Diagnostic Systems, Independence, OH) from 203 patients with Gram-positive organism infections were analyzed using the BC-GP assay within 12 h for the detection of 12 different organisms, including staphylococci, streptococci, and enterococci, as well as for the presence of 3 resistance markers (mecA, vanA, and vanB). Results were compared to those of routine laboratory methods for identification and susceptibility testing. For identification of organisms and detection of resistance markers in 178 monomicrobial positive blood cultures, the BC-GP assay showed 94% and 97% concordance, respectively, with routine methods. After 25 polymicrobial cultures were included, the results showed 92% and 96% agreement for identification and resistance markers, respectively, for a total of 203 positive cultures. In 6/25 polymicrobial cultures, at least 1 isolate was not detected. Concordance levels for detection of major pathogens such Staphylococcus aureus (n = 45) and enterococci (n = 19) were 98% and 95%, respectively. Agreement levels for detection of resistance markers such as mecA and vanA/B were 92% and 100%, respectively. The BC-GP assay is capable of providing rapid identification of Gram-positive cocci as well as detection of resistance markers directly from positive blood cultures at least 24 to 48 h earlier than conventional methods.

Tibbetts, Robert J.; Agotesku, Adam; Fey, Margaret; Hensley, Rhonda; Meier, Frederick A.

2013-01-01

28

Activity of Linezolid against 3,251 Strains of Uncommonly Isolated Gram-Positive Organisms: Report from the SENTRY Antimicrobial Surveillance Program?  

PubMed Central

Linezolid was tested against 32 species of uncommonly isolated gram-positive organisms (3,251 strains) by reference MIC methods and found to be highly active (MIC50 range, 0.25 to 2 ?g/ml; MIC90 range, 0.25 to 2 ?g/ml). Only one isolate (viridans group streptococcus; 0.03% of tested strains) was resistant to linezolid.

Jones, Ronald N.; Stilwell, Matthew G.; Hogan, Patricia A.; Sheehan, Daniel J.

2007-01-01

29

The identification of response regulator-specific binding sites reveals new roles of two-component systems in Bacillus cereus and closely related low-GC Gram-positives  

Microsoft Academic Search

In bacteria, environmental challenges are often translated into a transcriptional response via the cognate response regulators (RRs) of specialized two-component systems (TCSs). A phylogenetic footprinting\\/shadowing approach was designed and used to identify many novel RR-specific operators for species of the Bacillus cereus group and related Gram-positives. Analysis of the operator sequences revealed characteristic traits for each RR subfamily. For instance,

Been de M. W. H. J; Marieke J. Bart; Tjakko Abee; Roland J. Siezen; Christof Francke

2008-01-01

30

Optimizing identification of clinically relevant Gram-positive organisms by use of the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry system.  

PubMed

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) can be used as a method for the rapid identification of microorganisms. This study evaluated the Bruker Biotyper (MALDI-TOF MS) system for the identification of clinically relevant Gram-positive organisms. We tested 239 aerobic Gram-positive organisms isolated from clinical specimens. We evaluated 4 direct-smear methods, including "heavy" (H) and "light" (L) smears, with and without a 1-?l direct formic acid (FA) overlay. The quality measure assigned to a MALDI-TOF MS identification is a numerical value or "score." We found that a heavy smear with a formic acid overlay (H+FA) produced optimal MALDI-TOF MS identification scores and the highest percentage of correctly identified organisms. Using a score of ?2.0, we identified 183 of the 239 isolates (76.6%) to the genus level, and of the 181 isolates resolved to the species level, 141 isolates (77.9%) were correctly identified. To maximize the number of correct identifications while minimizing misidentifications, the data were analyzed using a score of ?1.7 for genus- and species-level identification. Using this score, 220 of the 239 isolates (92.1%) were identified to the genus level, and of the 181 isolates resolved to the species level, 167 isolates (92.2%) could be assigned an accurate species identification. We also evaluated a subset of isolates for preanalytic factors that might influence MALDI-TOF MS identification. Frequent subcultures increased the number of unidentified isolates. Incubation temperatures and subcultures of the media did not alter the rate of identification. These data define the ideal bacterial preparation, identification score, and medium conditions for optimal identification of Gram-positive bacteria by use of MALDI-TOF MS. PMID:23426925

McElvania Tekippe, Erin; Shuey, Sunni; Winkler, David W; Butler, Meghan A; Burnham, Carey-Ann D

2013-02-20

31

Pharmacodynamic properties of BAY 12-8039 on gram-positive and gram-negative organisms as demonstrated by studies of time-kill kinetics and postantibiotic effect.  

PubMed Central

Time-kill kinetics of BAY 12-8039 were studied at two inocula against three strains each of Bacteroides fragilis, Escherichia coli, Staphylococcus aureus, Haemophilus influenzae, and Streptococcus pyogenes. The postantibiotic effects of BAY 12-8039 were studied on three strains each of E. coli, S. aureus, H. influenzae, Streptococcus pyogenes, and Streptococcus pneumoniae. The pharmacodynamic data demonstrated that BAY 12-8039 has marked activity against gram-positive and gram-negative organisms (under both anaerobic and aerobic conditions) and anaerobes. BAY 12-8039 also exhibited a postantibiotic effect of >1 h for all strains except one E. coli strain.

Boswell, F J; Andrews, J M; Wise, R

1997-01-01

32

Emergence of Carbapenem resistant Gram negative and vancomycin resistant Gram positive organisms in bacteremic isolates of febrile neutropenic patients: A descriptive study  

PubMed Central

Background This study was conducted to evaluate drug resistance amongst bacteremic isolates of febrile neutropenic patients with particular emphasis on emergence of carbapenem resistant Gram negative bacteria and vancomycin resistant Enterococcus species. Methods A descriptive study was performed by reviewing the blood culture reports from febrile neutropenic patients during the two study periods i.e., 1999–00 and 2001–06. Blood cultures were performed using BACTEC 9240 automated system. Isolates were identified and antibiotic sensitivities were done using standard microbiological procedures. Results Seven twenty six febrile neutropenic patients were admitted during the study period. A total of 5840 blood cultures were received, off these 1048 (18%) were culture positive. Amongst these, 557 (53%) grew Gram positive bacteria, 442 (42%) grew Gram negative bacteria, 43 (4%) fungi and 6 (1%) anaerobes. Sixty (5.7%) out of 1048 positive blood cultures were polymicrobial. In the Gram negative bacteria, Enterobacteriaceae was the predominant group; E. coli was the most frequently isolated organism in both study periods. Amongst non- Enterobacteriaceae group, Pseudomonas aeruginosa was the commonest organism isolated during first study period followed by Acinetobacter spp. However, during the second period Acinetobacter species was the most frequent pathogen. Enterobacteriaceae group showed higher statistically significant resistance in the second study period against ceftriaxone, quinolone and piperacillin/tazobactam, whilst no resistance observed against imipenem/meropenem. The susceptibility pattern of Acinetobacter species shifted from sensitive to highly resistant one with significant p values against ceftriaxone, quinolone, piperacillin/tazobactam and imipenem/meropenem. Amongst Gram positive bacteria, MRSA isolation rate remained static, vancomycin resistant Enterococcus species emerged in second study period while no Staphylococcus species resistant to vancomycin was noted. Conclusion This rising trend of highly resistant organisms stresses the increasing importance of continuous surveillance system and stewardship of antibiotics as strategies in the overall management of patients with febrile neutropenia.

Irfan, Seema; Idrees, Faiza; Mehraj, Vikram; Habib, Faizah; Adil, Salman; Hasan, Rumina

2008-01-01

33

Isolation, characterization, and biological properties of an endotoxin-like material from the gram-positive organism Listeria monocytogenes.  

PubMed Central

The bacterial component responsible for the induction of transient cold agglutinin syndrome in rabbits after intravenous injection of heat-killed Listeria monocytogenes type 4B has been purified and biologically and chemically characterized. A purified immunoglobulin M cold agglutinin was prepared from high-titer sera resulting from the immunization of rabbits with heat-killed L. monocytogenes type 4B and was subsequently used to monitor the purification of the bacterial component responsible for its induction. The bacterial component was isolated from a hot phenol-water extract of lyophilized L. monocytogenes type 4B by multiple molecular sieve chromatography. Upon chemical analysis the purified material was found to be strikingly similar in chemical composition to gram-negative lipopolysaccharide endotoxins. The material contained 15% total fatty acid (of which 50% was beta-hydroxymyristic acid), 40 to 45% neutral sugar (glucose, galactose, and rhamnose), 11.5% amino sugar, 12% uronic acid, 2.5% 2-keto-3-deoxyoctonic acid, 2% heptose, 0.87% phosphorus, and 1.6% amino acid, thereby accounting for 85 to 90% of the weight of the component. Electron micrographs of the purified material were similar to those of lipopolysaccharide preparations from gram-negative organisms. The purified material exist in aqueous solutions as large aggregates, but can be dissociated into a single smaller subunit (3.1S) by dialysis against sodium dodecyl sulfate buffer. The listerial component was toxic and pyrogenic to rabbits, producing symptoms typical of gram-negative endotoxins. Activity in the limulus lysate gelation assay and in the carbocyanine dye assay provides a further link of this material with classical gram-negative endotoxins. Images

Wexler, H; Oppenheim, J D

1979-01-01

34

Gram-Positive Anaerobic Cocci  

PubMed Central

Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of organisms defined by their morphological appearance and their inability to grow in the presence of oxygen; most clinical isolates are identified to species in the genus Peptostreptococcus. GPAC are part of the normal flora of all mucocutaneous surfaces and are often isolated from infections such as deep organ abscesses, obstetric and gynecological sepsis, and intraoral infections. They have been little studied for several reasons, which include an inadequate classification, difficulties with laboratory identification, and the mixed nature of the infections from which they are usually isolated. Nucleic acid studies indicate that the classification is in need of radical revision at the genus level. Several species of Peptostreptococcus have recently been described, but others still await formal recognition. Identification has been based on carbohydrate fermentation tests, but most GPAC are asaccharolytic and use the products of protein degradation for their metabolism; the introduction of commercially available preformed enzyme kits affords a physiologically more appropriate method of identification, which is simple and relatively rapid and can be used in routine diagnostic laboratories. Recent reports have documented the isolation in pure culture of several species, notably Peptostreptococcus magnus, from serious infections. Studies of P. magnus have elucidated several virulence factors which correlate with the site of infection, and reveal some similarities to Staphylococcus aureus. P. micros is a strongly proteolytic species; it is increasingly recognized as an important pathogen in intraoral infections, particularly periodontitis, and mixed anaerobic deep-organ abscesses. Comparison of antibiotic susceptibility patterns reveals major differences between species. Penicillins are the antibiotics of choice, although some strains of P. anaerobius show broad-spectrum ?-lactam resistance.

Murdoch, D. A.

1998-01-01

35

Immunological crossreactivity to the catabolite control protein CcpA from Bacillus megaterium is found in many Gram-positive bacteria  

Microsoft Academic Search

The catabolite control protein CcpA from Bacillus megaterium was overproduced as a fusion protein to a 6xhis affinity tag and purified to homogeneity. Polyclonal antibodies of high affinity and specificity were raised against the purified protein. The serum did not crossreact with purified Lac repressor despite the fact that CcpA and LacI belong to the same protein family. Using this

Elke Küster; Evert J. Luesink; Willem M. de Vos; Wolfgang Hillen

1996-01-01

36

Antimicrobial Activity of the Investigational Pleuromutilin Compound BC-3781 Tested against Gram-Positive Organisms Commonly Associated with Acute Bacterial Skin and Skin Structure Infections  

PubMed Central

BC-3781 is a novel semisynthetic pleuromutilin antimicrobial agent developed as an intravenous and oral therapy for acute bacterial skin and skin structure infections (ABSSSI) and respiratory tract infections (RTI). BC-3781 and comparator agents were tested by the broth microdilution method against 1,893 clinical Gram-positive organisms predominantly causing ABSSSI. BC-3781 exhibited potent activity against methicillin-resistant Staphylococcus aureus (MIC50/90, 0.12/0.25 ?g/ml), coagulase-negative staphylococci (MIC50/90, 0.06/0.12 ?g/ml), ?-hemolytic streptococci (MIC50/90, 0.03/0.06 ?g/ml), viridans group streptococci (MIC50/90, 0.12/0.5 ?g/ml), and Enterococcus faecium (including vancomycin-nonsusceptible strains) (MIC50/90, 0.12/2 ?g/ml). Compared with other antibiotics in use for the treatment of ABSSSI, BC-3781 displayed the lowest MICs and only a minimal potential for cross-resistance with other antimicrobial classes.

Biedenbach, Douglas J.; Paukner, Susanne; Ivezic-Schoenfeld, Zrinka; Jones, Ronald N.

2012-01-01

37

Modeling the acid-base properties of bacterial surfaces: A combined spectroscopic and potentiometric study of the gram-positive bacterium Bacillus subtilis.  

PubMed

In this study, macroscopic and spectroscopic data were combined to develop a surface complexation model that describes the acid-base properties of Bacillus subtilis. The bacteria were freeze-dried and then resuspended in 0.1 M NaCl ionic medium. Macroscopic measurements included potentiometric acid-base titrations and electrophoretic mobility measurements. In addition, ATR-FTIR spectra of wet pastes from suspensions of Bacillus subtilis at different pH values were collected. The least-squares program MAGPIE was used to generate a surface complexation model that takes into account the presence of three acid-base sites on the surface: tripple bond COOH, tripple bond NH+, and tripple bond PO-, which were identified previously by XPS measurements. Both potentiometric titration data and ATR-FTIR spectra were used quantitatively, and electrostatic effects at the charged bacterial surface were accounted for using the constant capacitance model. The model was calculated using two different approaches: in the first one XPS data were used to constrain the ratio of the total concentrations of all three surface sites. The capacitance of the double layer, the total buffer capacity, and the deprotonation constants of the tripple bond NH+, tripple bond POH, and tripple bond COOH species were determined in the fit. A second approach is presented in which the ratio determined by XPS of the total concentrations of tripple bond NH+ to tripple bond PO- sites is relaxed. The total concentration of tripple bond PO- sites was determined in the fit, while the deprotonation constant for tripple bond POH was manually varied until the minimization led to a model which predicted an isoelectric point that resulted in consistency with electrophoretic mobility data. The model explains well the buffering capacity of Bacillus subtilis suspensions in a wide pH range (between pH=3 and pH=9) which is of considerable environmental interest. In particular, a similar quantitative use of the IR data opens up possibilities to model other bacterial surfaces at the laboratory scale and help estimate the buffering capacity of carboxylate-containing compounds in natural samples. PMID:17948795

Leone, Laura; Ferri, Diego; Manfredi, Carla; Persson, Per; Shchukarev, Andrei; Sjöberg, Staffan; Loring, John

2007-09-15

38

The replication terminator protein of the gram-positive bacterium Bacillus subtilis functions as a polar contrahelicase in gram-negative Escherichia coli.  

PubMed Central

The replication terminator protein (RTP) of Bacillus subtilis is a dimer with a monomeric molecular mass of 14.5 kDa. The protein terminates DNA replication at a specific binding site. Although the protein has been crystallized and its crystal structure has been solved, the lack of an in vitro replication system in B. subtilis has been a serious impediment to the analysis of the mechanism of action of this protein. We have discovered that the protein is functional in the Gram-negative bacterium Escherichia coli in vivo and in vitro. RTP blocked replication forks initiated from a ColE1 replication origin at the cognate DNA-binding site (BS3) in a polar mode. The protein did not block rolling circle replication initiated from the pT181 origin in cell extracts of Staphylococcus aureus. RTP antagonized the helicase activity of DnaB but not that of helicase II of E. coli. Thus, RTP functioned as a polar contrahelicase blocking a helicase that participates in symmetric DNA replication but it did not impede rolling circle replication nor the action of a helicase involved in DNA repair. Images

Kaul, S; Mohanty, B K; Sahoo, T; Patel, I; Khan, S A; Bastia, D

1994-01-01

39

Development of a novel direct bioautography-thin-layer chromatography test: optimization of growth conditions for gram-positive bacteria, Bacillus subtilis.  

PubMed

A TLC-direct bioautography (DB) assay using Bacillus subtilis as test bacteria was developed. Various factors affecting the microorganism's viability on the TLC plates were studied and verified for the flumequine standards. The Dhenasar's method called "direct sample determination" was used for TLC; the antibiotic samples were spotted on the TLC plates and subjected to bioautography without developing with a mobile phase. The best preincubation and incubation times of bacterial broth were found to be 1 h at 37 degrees C and 6 h at 37 degrees C. The optimal viscosity of broth was obtained by the addition of agarose to obtain a 0.05% solution in the Mueller-Hinton broth. The best incubation time of seeded TLC plates was 17 h at 37 degrees C. The plates were visualized by spraying with 0.2% aqueous 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide solution and incubated again for 0.5 h at 37 degrees C. The method was validated by determination of linearity, interday and intraday precision, LOD, and LOQ. The calibration curves showed good linearity in the range 0.005-0.5 microg (0.5-50.0 microg/mL). The regression coefficients were 0.9970 and 0.9955 for intraday and interday plots, respectively. The LOD of flumequine equalled 0.5 microg/mL, i.e., 5 ng of the antibiotic in the spot. The sensitivity of the developed TLC-DB test was compared with that of the two most commonly used standard antimicrobial susceptibility assays: agar disc diffusion and agar cylinder diffusion. The obtained minimum inhibitory concentration values clearly indicate much higher sensitivity of the TLC-DB method compared to the standard antimicrobial susceptibility assays. PMID:23767364

Grzelak, Edyta M; Majer-Dziedzic, Barbara; Choma, Irena M; Pilorz, Karol M

40

In Vitro and In Vivo Activities of PD 0305970 and PD 0326448, New Bacterial Gyrase\\/Topoisomerase Inhibitors with Potent Antibacterial Activities versus Multidrug-Resistant Gram-Positive and Fastidious Organism Groups  

Microsoft Academic Search

Received 23 October 2006\\/Returned for modification 21 November 2006\\/Accepted 11 January 2007 PD 0305970 and PD 0326448 are new bacterial gyrase and topoisomerase inhibitors (quinazoline-2,4-diones) that possess outstanding in vitro and in vivo activities against a wide spectrum of bacterial species including quinolone- and multidrug-resistant gram-positive and fastidious organism groups. The respective MICs (g\\/ml) for PD 0305970 capable of inhibiting

Michael D. Huband; Michael A. Cohen; Margaret Zurack; Debra L. Hanna; Laura A. Skerlos; Mark C. Sulavik; Glenn W. Gibson; Jeffrey W. Gage; Edmund Ellsworth; Michael A. Stier; Stephen J. Gracheck

2007-01-01

41

When Ribonucleases Come into Play in Pathogens: A Survey of Gram-Positive Bacteria  

PubMed Central

It is widely acknowledged that RNA stability plays critical roles in bacterial adaptation and survival in different environments like those encountered when bacteria infect a host. Bacterial ribonucleases acting alone or in concert with regulatory RNAs or RNA binding proteins are the mediators of the regulatory outcome on RNA stability. We will give a current update of what is known about ribonucleases in the model Gram-positive organism Bacillus subtilis and will describe their established roles in virulence in several Gram-positive pathogenic bacteria that are imposing major health concerns worldwide. Implications on bacterial evolution through stabilization/transfer of genetic material (phage or plasmid DNA) as a result of ribonucleases' functions will be covered. The role of ribonucleases in emergence of antibiotic resistance and new concepts in drug design will additionally be discussed.

Jester, Brian C.; Romby, Pascale; Lioliou, Efthimia

2012-01-01

42

Rolling-circle plasmids from Bacillus subtilis: complete nucleotide sequences and analyses of genes of pTA1015, pTA1040, pTA1050 and pTA1060, and comparisons with related plasmids from Gram-positive bacteria  

Microsoft Academic Search

Most small plasmids of Gram-positive bacteria use the rolling-circle mechanism of replication and several of these have been studied in considerable detail at the DNA level and for the function of their genes. Although most of the common laboratory Bacillus subtilis 168 strains do not contain plasmids, several industrial strains and natural soil isolates do contain rolling-circle replicating (RCR) plasmids.

Wilfried J. J. Meijer; G. Bea A. Wisman; Peter Terpstra; Peter B. Thorsted; Chris M. Thomas; S. Holsappel; Gerard Venema; Sierd Bron

1998-01-01

43

Innate sensors for Gram-positive bacteria  

Microsoft Academic Search

More than half of invasive bacterial infections are Gram-positive in origin. This class of bacteria has neither endotoxins nor an outer membrane, yet it generates some of the most powerful inflammatory responses known in medicine. Some recent seminal studies go a long way toward settling the controversies that surround the process by which Gram-positive bacterial surfaces trigger the human immune

Joerg R Weber; Philippe Moreillon; Elaine I Tuomanen

2003-01-01

44

Architecture and assembly of the Gram-positive cell wall  

PubMed Central

The bacterial cell wall is a mesh polymer of peptidoglycan – linear glycan strands crosslinked by flexible peptides – that determines cell shape and provides physical protection. While the glycan strands in thin “Gram-negative” peptidoglycan are known to run circumferentially around the cell, the architecture of the thicker “Gram-positive” form remains unclear. Using electron cryotomography, here we show that Bacillus subtilis peptidoglycan is a uniformly dense layer with a textured surface. We further show it rips circumferentially, curls and thickens at free edges, and extends longitudinally when denatured. Molecular dynamics simulations show that only atomic models based on the circumferential topology recapitulate the observed curling and thickening, in support of an “inside-to-outside” assembly process. We conclude that instead of being perpendicular to the cell surface or wrapped in coiled cables (two alternative models), the glycan strands in Gram-positive cell walls run circumferentially around the cell just as they do in Gram-negative cells. Together with providing insights into the architecture of the ultimate determinant of cell shape, this study is important because Gram-positive peptidoglycan is an important antibiotic target crucial to the viability of several important rod-shaped pathogens including Bacillus anthracis, Listeria monocytogenes, and Clostridium difficile.

Beeby, Morgan; Gumbart, James C.; Roux, Benoit; Jensen, Grant J.

2013-01-01

45

CtsR Regulation in mcsAB-Deficient Gram-Positive Bacteria  

PubMed Central

CtsR is an important repressor that modulates the transcription of class III stress genes in Gram-positive bacteria. In Bacillus subtilis, a model Gram-positive organism, the DNA binding activity of CtsR is regulated by McsAB-mediated phosphorylation of the protein where phosphorylated CtsR is a substrate for degradation by the ClpCP complex. Surprisingly, the mcsAB genes are absent from many Gram-positive bacteria, including streptococci; therefore, how CtsR activity is modulated in those bacteria remains unknown. Here we show that the posttranslational modulation of CtsR activity is different in Streptococcus mutans, a dental pathogen. We observed that of all of the Clp-related proteins, only ClpL is involved in the degradation of CtsR. Neither ClpP nor ClpC had any effect on the degradation of CtsR. We also found that phosphorylation of CtsR on a conserved arginine residue within the winged helix-turn-helix domain is necessary for modulation of the repressor activity of CtsR, as demonstrated by both in vitro and in vivo assays. We speculate that CtsR is regulated posttranslationally by a different mechanism in S. mutans and possibly in other streptococci.

Tao, Liang; Chattoraj, Partho

2012-01-01

46

Comparative analysis of gene expression among low G+C gram-positive genomes  

Microsoft Academic Search

We present a comparative analysis of predicted highly expressed (PHX) genes in the low G+C Gram-positive genomes of Bacillus subtilis, Bacillus halodurans, Listeria monocytogenes, Listeria innocua, Lactococcus lactis, Streptococcus pyogenes, Streptococcus pneumoniae, Staphylococcus aureus, Clostridium acetobutylicum, and Clostridium perfringens. Most enzymes acting in glycolysis and fermentation pathways are PHX in these genomes, but not those involved in the TCA cycle

Samuel Karlin; Julie Theriot; Jan Mrázek

2004-01-01

47

Translocation of proteins across the cell envelope of Gram-positive bacteria  

Microsoft Academic Search

In contrast to Gram-negative bacteria, secretory proteins of Gram-positive bacteria only need to traverse a single membrane to enter the extracellular environment. For this reason, Gram-positive bacteria (e.g. various Bacillus species) are often used in industry for the commercial production of extracellular proteins that can be produced in yields of several grams per liter culture medium. The central components of

Karel H. M. van Wely; Jelto Swaving; Roland Freudl; Arnold J. M. Driessen

2001-01-01

48

Hyaluronidases of Gram-positive bacteria  

Microsoft Academic Search

Bacterial hyaluronidases, enzymes capable of breaking down hyaluronate, are produced by a number of pathogenic Gram-positive bacteria that initiate infections at the skin or mucosal surfaces. Since reports of the hyaluronidases first appeared, there have been numerous suggestions as to the role of the enzyme in the disease process. Unlike some of the other more well studied virulence factors, much

Wayne L. Hynes; Sheryl Lynne Walton

2000-01-01

49

Pili in Gram-positive pathogens  

Microsoft Academic Search

Most bacterial pathogens have long filamentous structures known as pili or fimbriae extending from their surface. These structures are often involved in the initial adhesion of the bacteria to host tissues during colonization. In Gram-negative bacteria, pili are typically formed by non-covalent interactions between pilin subunits. By contrast, the recently discovered pili in Gram-positive pathogens are formed by covalent polymerization

Michèle A. Barocchi; Immaculada Margarit; Rino Rappuoli; John L. Telford; Guido Grandi

2006-01-01

50

Infections due to antibiotic-resistant gram-positive cocci  

Microsoft Academic Search

Summary  Gram-positive cocci are becoming increasingly resistant to traditionally used antimicrobial agents.Staphylococcus aureus, coagulase-negative staphylococci, the enterococcus, andStreptococcus pneumoniae are the most commonly encountered of such pathogens in clinical practice. Clinicians should be keenly aware of the usual\\u000a types of infections that are caused by these organisms and the importance of documenting susceptibilities of infecting strains.\\u000a The basic mechanisms of resistance

Gregory M. Caputo; Mary Singer; Scott White; Michael R. Weitekamp

1993-01-01

51

Mechanical consequences of cell-wall turnover in the elongation of a Gram-positive bacterium.  

PubMed

A common feature of walled organisms is their exposure to osmotic forces that challenge the mechanical integrity of cells while driving elongation. Most bacteria rely on their cell wall to bear osmotic stress and determine cell shape. Wall thickness can vary greatly among species, with Gram-positive bacteria having a thicker wall than Gram-negative bacteria. How wall dimensions and mechanical properties are regulated and how they affect growth have not yet been elucidated. To investigate the regulation of wall thickness in the rod-shaped Gram-positive bacterium Bacillus subtilis, we analyzed exponentially growing cells in different media. Using transmission electron and epifluorescence microscopy, we found that wall thickness and strain were maintained even between media that yielded a threefold change in growth rate. To probe mechanisms of elongation, we developed a biophysical model of the Gram-positive wall that balances the mechanical effects of synthesis of new material and removal of old material through hydrolysis. Our results suggest that cells can vary their growth rate without changing wall thickness or strain by maintaining a constant ratio of synthesis and hydrolysis rates. Our model also indicates that steady growth requires wall turnover on the same timescale as elongation, which can be driven primarily by hydrolysis rather than insertion. This perspective of turnover-driven elongation provides mechanistic insight into previous experiments involving mutants whose growth rate was accelerated by the addition of lysozyme or autolysin. Our approach provides a general framework for deconstructing shape maintenance in cells with thick walls by integrating wall mechanics with the kinetics and regulation of synthesis and turnover. PMID:23746506

Misra, Gaurav; Rojas, Enrique R; Gopinathan, Ajay; Huang, Kerwyn Casey

2013-06-01

52

Codon-optimized fluorescent proteins designed for expression in low-GC gram-positive bacteria.  

PubMed

Fluorescent proteins have wide applications in biology. However, not all of these proteins are properly expressed in bacteria, especially if the codon usage and genomic GC content of the host organism are not ideal for high expression. In this study, we analyzed the DNA sequences of multiple fluorescent protein genes with respect to codons and GC content and compared them to a low-GC gram-positive bacterium, Bacillus anthracis. We found high discrepancies for cyan fluorescent protein (CFP), yellow fluorescent protein (YFP), and the photoactivatable green fluorescent protein (PAGFP), but not GFP, with regard to GC content and codon usage. Concomitantly, when the proteins were expressed in B. anthracis, CFP- and YFP-derived fluorescence was undetectable microscopically, a phenomenon caused not by lack of gene transcription or degradation of the proteins but by lack of protein expression. To improve expression in bacteria with low genomic GC contents, we synthesized a codon-optimized gfp and constructed optimized photoactivatable pagfp, cfp, and yfp, which were in contrast to nonoptimized genes highly expressed in B. anthracis and in another low-GC gram-positive bacterium, Staphylococcus aureus. Using optimized GFP as a reporter, we were able to monitor the activity of the protective antigen promoter of B. anthracis and confirm its dependence on bicarbonate and regulators present on virulence plasmid pXO1. PMID:19181829

Sastalla, Inka; Chim, Kannie; Cheung, Gordon Y C; Pomerantsev, Andrei P; Leppla, Stephen H

2009-01-30

53

A CYTOCHEMICAL LOCALIZATION OF REDUCTIVE SITES IN A GRAM-POSITIVE BACTERIUM  

PubMed Central

In bacteria the exact location of a respiratory enzyme system comparable to that of the mitochondria of other cells has remained uncertain. On the one hand, the existence of particulate "bacterial mitochondria" has been advocated (Mudd); on the other hand, important enzymes of the respiratory chain were recovered in the cytoplasmic membranes associated with some granular material (Weibull). In order to gain insight into this question, sites of reducing activity were localized in thin sections of bacteria using the reduction of potassium tellurite as an indicator. When this salt was added to the culture medium of Bacillus subtilis, it turned out that in this Gram-positive organism the reduced product is strictly bound at two sites, and that the plasma membrane does not materially gain in electron opacity through deposition of the reduced product. The reduction product is found on or in the membranes of particular organelles, which may possibly be regarded as the mitochondrial equivalents in Gram-positive bacteria, and which are sometimes seen connected to the plasma membrane. The second location is in thin rod-like elements at the cell periphery, possibly the sites from which the flagella emerge.

van Iterson, Woutera; Leene, W.

1964-01-01

54

Bacteriocins of gram-positive bacteria.  

PubMed Central

In recent years, a group of antibacterial proteins produced by gram-positive bacteria have attracted great interest in their potential use as food preservatives and as antibacterial agents to combat certain infections due to gram-positive pathogenic bacteria. They are ribosomally synthesized peptides of 30 to less than 60 amino acids, with a narrow to wide antibacterial spectrum against gram-positive bacteria; the antibacterial property is heat stable, and a producer strain displays a degree of specific self-protection against its own antibacterial peptide. In many respects, these proteins are quite different from the colicins and other bacteriocins produced by gram-negative bacteria, yet customarily they also are grouped as bacteriocins. Although a large number of these bacteriocins (or bacteriocin-like inhibitory substances) have been reported, only a few have been studied in detail for their mode of action, amino acid sequence, genetic characteristics, and biosynthesis mechanisms. Nevertheless, in general, they appear to be translated as inactive prepeptides containing an N-terminal leader sequence and a C-terminal propeptide component. During posttranslational modifications, the leader peptide is removed. In addition, depending on the particular type, some amino acids in the propeptide components may undergo either dehydration and thioether ring formation to produce lanthionine and beta-methyl lanthionine (as in lantibiotics) or thio ester ring formation to form cystine (as in thiolbiotics). Some of these steps, as well as the translocation of the molecules through the cytoplasmic membrane and producer self-protection against the homologous bacteriocin, are mediated through specific proteins (enzymes). Limited genetic studies have shown that the structural gene for such a bacteriocin and the genes encoding proteins associated with immunity, translocation, and processing are present in a cluster in either a plasmid, the chromosome, or a transposon. Following posttranslational modification and depending on the pH, the molecules may either be released into the environment or remain bound to the cell wall. The antibacterial action against a sensitive cell of a gram-positive strain is produced principally by destabilization of membrane functions. Under certain conditions, gram-negative bacterial cells can also be sensitive to some of these molecules. By application of site-specific mutagenesis, bacteriocin variants which may differ in their antimicrobial spectrum and physicochemical characteristics can be produced. Research activity in this field has grown remarkably but sometimes with an undisciplined regard for conformity in the definition, naming, and categorization of these molecules and their genetic effectors. Some suggestions for improved standardization of nomenclature are offered.

Jack, R W; Tagg, J R; Ray, B

1995-01-01

55

Bacteriocins of gram-positive bacteria.  

PubMed

In recent years, a group of antibacterial proteins produced by gram-positive bacteria have attracted great interest in their potential use as food preservatives and as antibacterial agents to combat certain infections due to gram-positive pathogenic bacteria. They are ribosomally synthesized peptides of 30 to less than 60 amino acids, with a narrow to wide antibacterial spectrum against gram-positive bacteria; the antibacterial property is heat stable, and a producer strain displays a degree of specific self-protection against its own antibacterial peptide. In many respects, these proteins are quite different from the colicins and other bacteriocins produced by gram-negative bacteria, yet customarily they also are grouped as bacteriocins. Although a large number of these bacteriocins (or bacteriocin-like inhibitory substances) have been reported, only a few have been studied in detail for their mode of action, amino acid sequence, genetic characteristics, and biosynthesis mechanisms. Nevertheless, in general, they appear to be translated as inactive prepeptides containing an N-terminal leader sequence and a C-terminal propeptide component. During posttranslational modifications, the leader peptide is removed. In addition, depending on the particular type, some amino acids in the propeptide components may undergo either dehydration and thioether ring formation to produce lanthionine and beta-methyl lanthionine (as in lantibiotics) or thio ester ring formation to form cystine (as in thiolbiotics). Some of these steps, as well as the translocation of the molecules through the cytoplasmic membrane and producer self-protection against the homologous bacteriocin, are mediated through specific proteins (enzymes). Limited genetic studies have shown that the structural gene for such a bacteriocin and the genes encoding proteins associated with immunity, translocation, and processing are present in a cluster in either a plasmid, the chromosome, or a transposon. Following posttranslational modification and depending on the pH, the molecules may either be released into the environment or remain bound to the cell wall. The antibacterial action against a sensitive cell of a gram-positive strain is produced principally by destabilization of membrane functions. Under certain conditions, gram-negative bacterial cells can also be sensitive to some of these molecules. By application of site-specific mutagenesis, bacteriocin variants which may differ in their antimicrobial spectrum and physicochemical characteristics can be produced. Research activity in this field has grown remarkably but sometimes with an undisciplined regard for conformity in the definition, naming, and categorization of these molecules and their genetic effectors. Some suggestions for improved standardization of nomenclature are offered. PMID:7603408

Jack, R W; Tagg, J R; Ray, B

1995-06-01

56

In Vitro and In Vivo Activities of PD 0305970 and PD 0326448, New Bacterial Gyrase/Topoisomerase Inhibitors with Potent Antibacterial Activities versus Multidrug-Resistant Gram-Positive and Fastidious Organism Groups?  

PubMed Central

PD 0305970 and PD 0326448 are new bacterial gyrase and topoisomerase inhibitors (quinazoline-2,4-diones) that possess outstanding in vitro and in vivo activities against a wide spectrum of bacterial species including quinolone- and multidrug-resistant gram-positive and fastidious organism groups. The respective MICs (?g/ml) for PD 0305970 capable of inhibiting ?90% of bacterial strains tested ranged from 0.125 to 0.5 versus staphylococci, 0.03 to 0.06 versus streptococci, 0.25 to 2 versus enterococci, and 0.25 to 0.5 versus Moraxella catarrhalis, Haemophilus influenzae, Listeria monocytogenes, Legionella pneumophila, and Neisseria spp. PD 0326448 MIC90s were generally twofold higher versus these same organism groups. Comparative quinolone MIC90 values were 4- to 512-fold higher than those of PD 0305970. In testing for frequency of resistance, PD 0305970 and levofloxacin showed low levels of development of spontaneous resistant mutants versus both Staphylococcus aureus and Streptococcus pneumoniae. Unlike quinolones, which target primarily gyrA and parC, analysis of resistant mutants in S. pneumoniae indicates that the likely targets of PD 0305970 are gyrB and parE. PD 0305970 demonstrated rapid bactericidal activity by in vitro time-kill testing versus streptococci. This bactericidal activity carried over to in vivo testing, where PD 0305970 and PD 0326448 displayed outstanding Streptococcus pyogenes 50% protective doses (PD50s) (oral dosing) of 0.7 and 3.6 mg/kg, respectively (ciprofloxacin and levofloxacin PD50s were >100 and 17.7 mg/kg, respectively). PD 0305970 was also potent in a pneumococcal pneumonia mouse infection model (PD50 = 3.2 mg/kg) and was 22-fold more potent than levofloxacin.

Huband, Michael D.; Cohen, Michael A.; Zurack, Margaret; Hanna, Debra L.; Skerlos, Laura A.; Sulavik, Mark C.; Gibson, Glenn W.; Gage, Jeffrey W.; Ellsworth, Edmund; Stier, Michael A.; Gracheck, Stephen J.

2007-01-01

57

REPORT ANTIBACTERIAL ACTIVITY OF OREGANO (ORIGANUM VULGARE LINN.) AGAINST GRAM POSITIVE BACTERIA  

Microsoft Academic Search

The present investigation is focused on antibacterial potential of infusion, decoction and essential oil of oregano (Origanum vulgare) against 111 Gram-positive bacterial isolates belonging to 23 different species related to 3 genera. Infusion and essential oil exhibited antibacterial activity against Staphylococcus saprophyticus, S. aureus, Micrococcus roseus, M. kristinae, M. nishinomiyaensis, M. lylae, M. luteus, M. sedentarius, M. varians, Bacillus megaterium,

SABAHAT SAEED; PERWEEN TARIQ

58

Determination of the total charge in the cell walls of Gram-positive bacteria  

Microsoft Academic Search

The charge in the bacterial wall originates from the dissociation of acidic groups such as carboxyl, phosphate and amino groups. The degree of dissociation of these chargeable groups is a function of the pH and the activity of the surrounding electrolyte solution. In this study the cell wall charge density of Gram-positive bacterial strains, including four coryneforms and a Bacillus

Albert van der Wal; Willem Norde; Alexander J. B. Zehnder; Johannes Lyklema

1997-01-01

59

Expression systems for industrial Gram-positive bacteria with low guanine and cytosine content  

Microsoft Academic Search

Recent years have seen an increase in the development of gene expression systems for industrial Gram-positive bacteria with low guanine and cytosine content that belong to the genera Bacillus, Clostridium, Lactococcus, Lactobacillus, Staphylococcus and Streptococcus. In particular, considerable advances have been made in the construction of inducible gene expression systems based on the capacity of these bacteria to utilize specific

Willem M. de Vos; Michiel Kleerebezem; Oscar P. Kuipers

1997-01-01

60

Management of Gram-Positive Bacterial Disease: Staphylococcus aureus , Streptococcal, Pneumococcal and Enterococcal Infections  

Microsoft Academic Search

\\u000a Gram-positive bacteria are a diverse group of organisms that are a major source of morbidity and mortality in patients with\\u000a cancer. The increasing use of long-term indwelling central catheters and cytotoxic chemotherapies has contributed to the emergence\\u000a of Gram-positive bacteria as the leading cause of bacteremia in cancer patients. These organisms are also among the foremost\\u000a causes of pneumonia, skin

Samuel Shelburne; Daniel M. Musher

61

Bacillus coagulans  

MedlinePLUS

... It is used similarly to lactobacillus and other probiotics as "beneficial" bacteria. People take Bacillus coagulans for ... B. Coagulans, Bacillus Bacteria, Bacillus Probiotics, Bactéries Bacilles, ... en Forme de Bâtonnet, Gram Positive Spore-Forming Rod, L. Sporogenes, ...

62

Sortase enzymes in Gram-positive bacteria  

PubMed Central

Summary In Gram-positive bacteria proteins are displayed on the cell surface using sortase enzymes. These cysteine transpeptidases join proteins bearing an appropriate sorting signal to strategically positioned amino groups on the cell surface. Working alone, or in concert with other enzymes, sortases either attach proteins to the cross-bridge peptide of the cell wall or they link proteins together to form pili. Because surface proteins play a fundamental role in microbial physiology and are frequently virulence factors, sortase enzymes have been intensely studied since their discovery a little more than a decade ago. Based on their primary sequences and functions sortases can be partitioned into distinct families called class A to F enzymes. Most bacteria elaborate their surfaces using more than one type of sortase that function non-redundantly by recognizing unique sorting signals within their protein substrates. Here we review what is known about the functions of these enzymes and the molecular basis of catalysis. Particular emphasis is placed on ‘pilin’ specific class C sortases that construct structurally complex pili. Exciting new data have revealed that these enzymes are amazingly promiscuous in the substrates that they can employ and that there is a startling degree of diversity in their mechanism of action. We also review recent data that suggest that sortases are targeted to specific sites on the cell surface where they work with other sortases and accessory factors to properly function.

Spirig, Thomas; Weiner, Ethan M.; Clubb, Robert T.

2013-01-01

63

The role of ? B in the stress response of Gram-positive bacteria – targets for food preservation and safety  

Microsoft Academic Search

The alternative sigma factor ¿B modulates the stress response of several Gram-positive bacteria, including Bacillus subtilis and the food-borne human pathogens Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. In all these bacteria, ¿B is responsible for the transcription of genes that can confer stress resistance to the vegetative cell. Recent findings indicate that ¿B also plays an important role in

Willem van Schaik; Tjakko Abee

2005-01-01

64

Comparison of Cd Binding Mechanisms by Gram-Positive, Gram-Negative and Consortia of Bacteria Using XAFS  

NASA Astrophysics Data System (ADS)

A quantitative comparison of the Cd binding mechanism to Gram-positive (Bacillus subtilis) and Gram-negative bacteria (Shewanella oneidensis) is presented. At pH 6.0, EXAFS data for the Gram-positive bacteria were modeled using carboxyl and phosphoryl sites only. However, additional sulfide sites were required to model the spectrum from the Gram-negative bacteria under similar experimental conditions. Cd binding to a bacterial consortium at the same pH value, sampled from natural river water, was modeled using the models developed for the individual Gram-positive and Gram-negative bacterial strains.

Mishra, Bhoopesh; Fein, Jeremy B.; Boyanov, Maxim I.; Kelly, Shelly D.; Kemner, Kenneth M.; Bunker, Bruce A.

2007-02-01

65

Pathogenesis of Gram-Positive Bacterial Endophthalmitis  

Microsoft Academic Search

The severity of endophthalmitis has been associated generally with the virulence of the offending pathogen. However, precisely what constitutes the virulence in intraocular infections remains ill defined. We therefore sought to identify the basis for virulence for three common ocular pathogens (Bacillus cereus, Enterococcus faecalis, and Staphylococcus aureus) in terms of intraocular growth rates, bacterial localization patterns, and the contribution

MICHELLE C. CALLEGAN; MARY C. BOOTH; BRADLEY D. JETT; MICHAEL S. GILMORE; Dean A. McGee

1999-01-01

66

Vancomycin-resistant Gram-positive bacterial endophthalmitis: epidemiology, treatment options, and outcomes  

PubMed Central

Background The purpose of this study is to evaluate the microbiological profile and treatment outcomes of vancomycin-resistant Gram-positive bacterial endophthalmitis. Medical records of all patients with Gram-positive bacterial endophthalmitis resistant to vancomycin presenting between 1 January 2005 and 31 December 2010 were reviewed in this noncomparative, consecutive, retrospective case series. Favorable outcome was defined as a best-corrected visual acuity of ?20/200. Results Out of 682 culture-positive endophthalmitis isolates, 448/682 (65.6%) were associated with Gram-positive bacteria. In vitro resistance to vancomycin was noted in 7/448 (1.56%). Three cases were posttraumatic, three were postoperative, and one was endogenous in origin. Four Bacillus isolates, two Staphylococcus isolates, and an Enterococcus isolate were resistant. Isolates resistant to vancomycin were sensitive in vitro to ciprofloxacin in 6/7 (86%) patients. Presenting visual acuity was light perception in all seven cases. Favorable outcome was achieved in only 1/7 (14.3%) cases. Conclusions Vancomycin-resistant endophthalmitis is uncommon and usually associated with poor visual outcome. Bacillus sp. is the most frequent Gram-positive bacteria resistant to vancomycin. Fluoroquinolones like ciprofloxacin may be considered as a useful alternative in vancomycin-resistant endophthalmitis.

2013-01-01

67

Rhamnolipid–Biosurfactant Permeabilizing Effects on Gram-Positive and Gram-Negative Bacterial Strains  

Microsoft Academic Search

The potential of biosurfactant PS to permeabilize bacterial cells of Pseudomonas aeruginosa, Escherichia coli, and Bacillus subtilis on growing (in vivo) and resting (in vitro) cells was studied. Biosurfactant was shown to have a neutral or detrimental effect\\u000a on the growth of Gram-positive strains, and this was dependent on the surfactant concentration. The growth of Gram-negative\\u000a strains was not influenced

A. V. Sotirova; D. I. Spasova; D. N. Galabova; E. Karpenko; A. Shulga

2008-01-01

68

Multidrug resistance in hydrocarbon-tolerant Gram-positive and Gram-negative bacteria.  

PubMed

New Gram-positive and Gram-negative bacteria were isolated from Poeni oily sludge, using enrichment procedures. The six Gram-positive strains belong to Bacillus, Lysinibacillus and Rhodococcus genera. The eight Gram-negative strains belong to Shewanella, Aeromonas, Pseudomonas and Klebsiella genera. Isolated bacterial strains were tolerant to saturated (i.e., n-hexane, n-heptane, n-decane, n-pentadecane, n-hexadecane, cyclohexane), monoaromatic (i.e., benzene, toluene, styrene, xylene isomers, ethylbenzene, propylbenzene) and polyaromatic (i.e., naphthalene, 2-methylnaphthalene, fluorene) hydrocarbons, and also resistant to different antimicrobial agents (i.e., ampicillin, kanamycin, rhodamine 6G, crystal violet, malachite green, sodium dodecyl sulfate). The presence of hydrophilic antibiotics like ampicillin or kanamycin in liquid LB-Mg medium has no effects on Gram-positive and Gram-negative bacteria resistance to toxic compounds. The results indicated that Gram-negative bacteria are less sensitive to toxic compounds than Gram-positive bacteria, except one bacteria belonging to Lysinibacillus genus. There were observed cellular and molecular modifications induced by ampicillin or kanamycin to isolated bacterial strains. Gram-negative bacteria possessed between two and four catabolic genes (alkB, alkM, alkB/alkB1, todC1, xylM, PAH dioxygenase, catechol 2,3-dioxygenase), compared with Gram-positive bacteria (except one bacteria belonging to Bacillus genus) which possessed one catabolic gene (alkB/alkB1). Transporter genes (HAE1, acrAB) were detected only in Gram-negative bacteria. PMID:21478643

Stancu, Mihaela Marilena; Grifoll, Magdalena

2011-01-01

69

Identification, Evolution, and Essentiality of the Mevalonate Pathway for Isopentenyl Diphosphate Biosynthesis in Gram-Positive Cocci  

PubMed Central

The mevalonate pathway and the glyceraldehyde 3-phosphate (GAP)–pyruvate pathway are alternative routes for the biosynthesis of the central isoprenoid precursor, isopentenyl diphosphate. Genomic analysis revealed that the staphylococci, streptococci, and enterococci possess genes predicted to encode all of the enzymes of the mevalonate pathway and not the GAP-pyruvate pathway, unlike Bacillus subtilis and most gram-negative bacteria studied, which possess only components of the latter pathway. Phylogenetic and comparative genome analyses suggest that the genes for mevalonate biosynthesis in gram-positive cocci, which are highly divergent from those of mammals, were horizontally transferred from a primitive eukaryotic cell. Enterococci uniquely encode a bifunctional protein predicted to possess both 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and acetyl-CoA acetyltransferase activities. Genetic disruption experiments have shown that five genes encoding proteins involved in this pathway (HMG-CoA synthase, HMG-CoA reductase, mevalonate kinase, phosphomevalonate kinase, and mevalonate diphosphate decarboxylase) are essential for the in vitro growth of Streptococcus pneumoniae under standard conditions. Allelic replacement of the HMG-CoA synthase gene rendered the organism auxotrophic for mevalonate and severely attenuated in a murine respiratory tract infection model. The mevalonate pathway thus represents a potential antibacterial target in the low-G+C gram-positive cocci.

Wilding, E. Imogen; Brown, James R.; Bryant, Alexander P.; Chalker, Alison F.; Holmes, David J.; Ingraham, Karen A.; Iordanescu, Serban; So, Chi Y.; Rosenberg, Martin; Gwynn, Michael N.

2000-01-01

70

Moderately halophilic gram-positive bacterial diversity in hypersaline environments  

Microsoft Academic Search

Moderately halophilic bacteria are microorganisms that grow optimally in media containing 3%–15% (w\\/v) salt. They are represented\\u000a by a heterogeneous group of microorganisms included in many different genera. Gram-negative moderately halophilic bacteria\\u000a have been studied in more detail, but studies on gram-positive species are more scarce. Recent studies carried out by our\\u000a research group on gram-positive moderate halophiles have permitted

Antonio Ventosa; M. Carmen Márquez; María J. Garabito; David R. Arahal

1998-01-01

71

Chocolate agar, a differential medium for gram-positive cocci.  

PubMed Central

Reactions incurred on chocolate agar by gram-positive cocci were correlated with species identity. Darkening and clearing of the medium was usually associated with the species Staphylococcus epidermidis, Staphylococcus aureus, Staphylococcus simulans, and Streptococcus faecalis. Yellowing of chocolate agar was associated with alpha-hemolytic species of Streptococcus. The study demonstrated that reactions occurring on chocolate agar are useful in identifying gram-positive cocci.

Gunn, B A

1984-01-01

72

Assembly of pili in Gram-positive bacteria  

Microsoft Academic Search

The formation of adhesive pili on the surface of Gram-negative bacteria has been studied in detail, whereas the pilus assembly pathways in Gram-positive bacteria remain to be characterized. Gram-positive microbes use the cell wall peptidoglycan as a surface organelle for the covalent attachment of proteins; a strategy that involves sorting signals of surface protein precursors and sortase, a transpeptidase that

Hung Ton-That; Olaf Schneewind

2004-01-01

73

Testing of different antibiotics against Gram-positive and Gram-negative bacteria isolated from plant tissue culture  

Microsoft Academic Search

Different Gram-positive and Gram-negative bacteria (Staphylococcus xylosus, S. aureus, S. cohnii, Bacillus sp., Corynebacterium sp., Pseudomonas vesicularis) were isolated from homogenized shoot tips of Drosera rotundifolia, Spatiphyllum sp., Syngonium cv. White butterfly, Nephrolepis exaltata cv. Teddy Junior. Growth inhibition of selected bacterial strains was examined using 28 different single antibiotics and 7 antibiotic mixtures. It was found that with the

W. Kneifel; W. Leonhardt

1992-01-01

74

Telavancin: a new lipoglycopeptide for gram-positive infections.  

PubMed

Telavancin is a lipoglycopeptide derivative of vancomycin. Similar to vancomycin, it demonstrates activity in vitro against a variety of Gram-positive pathogens, including but not limited to methicillin-resistant Staphylococccus aureus (MRSA) and penicillin-resistant Streptococcus pneumoniae (PRSP). Modifications to vancomycin's structure expanded telavancin's spectrum of activity in vitro to include organisms such as glycopeptide-intermediate S. aureus (GISA), vancomycin-resistant S. aureus (VRSA) and vancomycin-resistant enterococci (VRE). However, the clinical implications of this are currently unknown. Similar to other glycopeptides, televancin binds to the D-alanyl-D-alanine (D-Ala-D-Ala) terminus in Gram-positive organisms, resulting in inhibition of bacterial cell wall synthesis. In addition, telavancin causes depolarization of the bacterial cell membrane and increased membrane permeability. The resulting activity in vitro is rapidly bactericidal and concentration dependent, with the ratio of area under the time concentration curve to minimum inhibitory concentration (AUC/MIC) as the best predictor of activity in animal models to date. In humans, telavancin exhibits a pharmacokinetic profile that permits once-daily intravenous administration. Doses of 7.5 and 10 mg/kg/day have been studied in clinical trials. The need for dosage adjustments based on age, gender and obesity appear unnecessary. In addition, moderate hepatic impairment does not appreciably alter the pharmacokinetics of the drug. Because telavancin is extensively cleared by the kidneys, dosage adjustments will be required in patients with moderate to severe renal impairment. Published phase II and III clinical trials have shown telavancin to be comparable to standard therapy for the treatment of complicated skin and soft tissue infections. Clinical trials in the treatment of S. aureus bacteremia and hospital-acquired pneumonia are under way. Adverse effects overall appear to be mild and reversible, with taste disturbance, foamy urine, headache, procedural site pain, nausea and vomiting being the most commonly reported. However, renal toxicity was reported more frequently with telavancin than with vancomycin in two phase III clinical trials (3% versus 1%). Prolongation of the corrected QT (QTc) interval has been more common with telavancin than comparator agents, but no clinically significant electrocardiogram (ECG) changes or cardiac abnormalities have been observed to date. Although human pregnancy data is not currently available, animal data revealed limb malformations that were possibly related to telavancin therapy. Therefore, the potential teratogenicity of this agent must be considered in women who are pregnant or may become pregnant. PMID:19436839

Smith, Winter J; Drew, Richard H

2009-03-01

75

In Vitro Activity of RU 64004, a New Ketolide Antibiotic, against Gram-Positive Bacteria  

Microsoft Academic Search

The comparative in vitro activity of RU 64004 (also known as HMR 3004), a new ketolide antibiotic, was tested by agar dilution against approximately 500 gram-positive organisms, including multiply resistant enterococci, streptococci, and staphylococci. All streptococci were inhibited by <1 mg of RU 64004 per ml. The ketolide was more potent than other macrolides against erythromycin A-susceptible staphylococci and was

T. SCHULIN; C. B. WENNERSTEN; R. C. MOELLERING; G. M. ELIOPOULOS

1997-01-01

76

Aerobic Respiration in the Gram-Positive Bacteria  

Microsoft Academic Search

The group of Gram-positive bacteria is a major phylum of prokaryotes, including several typical saprophytic aerobes. Their\\u000a respiratory chains are apparently similar to those of eukaryotic mitochondria, but in several points are different from them.\\u000a The respiratory chain of Gram-positives, like many bacteria, contains branched electron transfer pathways, usually 1-3 heme-Cu\\u000a oxidases, but SoxB-type cytochrome c oxidases (cytochrome b(a\\/o)3) are

Nobhuito Sone; Cecilia Hagerhall; Junshi Sakamoto

77

Cellular reprogramming by gram-positive bacterial components: a review.  

PubMed

LPS tolerance has been the focus of extensive scientific and clinical research over the last several decades in an attempt to elucidate the sequence of changes that occur at a molecular level in tolerized cells. Tolerance to components of gram-positive bacterial cell walls such as bacterial lipoprotein and lipoteichoic acid is a much lesser studied, although equally important, phenomenon. This review will focus on cellular reprogramming by gram-positive bacterial components and examines the alterations in cell surface receptor expression, changes in intracellular signaling, gene expression and cytokine production, and the phenomenon of cross-tolerance. PMID:16885502

Buckley, Julliette M; Wang, Jiang Huai; Redmond, H Paul

2006-08-02

78

Zinc, a structural component of adenylate kinases from gram-positive bacteria.  

PubMed Central

The recent finding that Bacillus stearothermophilus adenylate kinase contains a zinc atom coordinated to four cysteines prompted us to investigate the metal-binding properties of the enzyme from various bacteria. We conclude that zinc was present only in adenylate kinase from gram-positive species and that this property is correlated with the presence of three or four Cys residues in the sequence Cys-X2-Cys-X16-Cys-X2-Cys/Asp, in which X stands for different amino acid residues.

Gilles, A M; Glaser, P; Perrier, V; Meier, A; Longin, R; Sebald, M; Maignan, L; Pistotnik, E; Barzu, O

1994-01-01

79

Biosynthesis of Auxin by the Gram-Positive Phytopathogen Rhodococcus fascians Is Controlled by Compounds Specific to Infected Plant Tissues  

Microsoft Academic Search

The role and metabolism of indole-3-acetic acid in gram-negative bacteria is well documented, but little is known about indole-3-acetic acid biosynthesis and regulation in gram-positive bacteria. The phytopathogen Rhodococcus fascians, a gram-positive organism, incites diverse developmental alterations, such as leafy galls, on a wide range of plants. Phenotypic analysis of a leafy gall suggests that auxin may play an important

Olivier Vandeputte; Sevgi Oden; Adeline Mol; Danny Vereecke; Koen Goethals; Mondher El Jaziri; Els Prinsen

2005-01-01

80

A Microdomain for Protein Secretion in Gram-Positive Bacteria  

Microsoft Academic Search

Gram-positive bacteria face unique challenges in generating biologically active conformations for their exported proteins because they lack a dedicated compartment for folding secreted polypeptides. We have discovered that protein secretion by way of the general secretory (Sec) pathway in the important human pathogen Streptococcus pyogenes proceeds through a single microdomain. Unlike other mechanisms for asymmetry involving the Sec pathway, proteins

Jason Rosch; Michael Caparon

2004-01-01

81

Comparative in vitro activity of levofloxacin and ofloxacin against Gram-positive bacteria  

Microsoft Academic Search

The in vitro activity of levofloxacin against 506 Gram-positive bacteria was compared with those of D(?)-ofloxacin, ofloxacin, ciprofloxacin, and sparfloxacin. Levofloxacin was generally twice as active as ofloxacin against these organisms (range, 0–3 twofold dilutions). Sparfloxacin appeared to have the greatest activity overall, but for several groups of organisms minimum inhibitory concentrations (MIC90s) of this com pound were within one

George M. Eliopoulos; Christine B. Wennersten; Robert C. Moellering

1996-01-01

82

Peptide signaling in Staphylococcus aureus and other Gram-positive bacteria  

Microsoft Academic Search

There are two basic types of bacterial communication systems—those in which the signal is directed solely at other organisms and those in which the signal is sensed by the producing organism as well. The former are involved primarily in conjugation; the latter in adaptation to the environment. Gram-positive bacteria use small peptides for both types of signaling, whereas Gram-negative bacteria

Gholson J. Lyon; Richard P. Novick

2004-01-01

83

Molecular Characterization of the Acute Inflammatory Response to Infections with Gram-Negative versus Gram-Positive Bacteria  

PubMed Central

Sepsis caused by gram-negative bacteria and that caused by gram-positive bacteria often manifest similar clinical features. We investigated plasma proinflammatory cytokine profiles in patients with sepsis due to gram-positive and gram-negative bacteria and studied the cytokine production and differential gene regulation of leukocytes stimulated ex vivo with Escherichia coli lipopolysaccharide or heat-killed Staphylococcus aureus. Concentrations of tumor necrosis factor alpha, interleukin 1 receptor antagonist (IL-1Ra), IL-8, IL-10, IL-18 binding protein, procalcitonin, and protein C in plasma did not differ between patients with sepsis due to gram-negative and gram-positive bacteria. However, plasma IL-1?, IL-6, and IL-18 concentrations were significantly higher in patients with sepsis due to gram-positive bacteria. Ex vivo stimulation of whole blood with heat-killed S. aureus markedly increased IL-1? and IL-18 levels more than E. coli lipopolysaccharide stimulation. Microarray analysis revealed at least 359 cross-validated probe sets (genes) significant at the P < 0.001 level whose expression discriminated among gram-negative-organism-stimulated, gram-positive-organism-stimulated, and unstimulated whole-blood leukocytes. The host inflammatory responses to gram-negative and gram-positive stimuli share some common response elements but also exhibit distinct patterns of cytokine appearance and leukocyte gene expression.

Feezor, Robert J.; Oberholzer, Caroline; Baker, Henry V.; Novick, Daniela; Rubinstein, Menachem; Moldawer, Lyle L.; Pribble, John; Souza, Sonia; Dinarello, Charles A.; Ertel, Wolfgang; Oberholzer, Andreas

2003-01-01

84

Genomics of the Bacillus cereus group of organisms  

Microsoft Academic Search

Members of the Bacillus cereus group of organisms include Bacillus cereus, Bacillus anthracis and Bacillus thuringiensis. Collectively, these organisms represent microbes of high economic, medical and biodefense importance. Given this significance, this group contains the highest number of closely related fully sequenced genomes, giving the unique opportunity for thorough comparative genomic analyses. Much of the disease and host specificity of

David A. Rasko; Michael R. Altherr; Cliff S. Han; Jacques Ravel

2005-01-01

85

Buffering capacity and membrane H+ conductance of neutrophilic and alkalophilic gram-positive bacteria.  

PubMed

Buffering capacity and membrane H+ conductance were examined in three gram-positive bacteria, Staphylococcus aureus, Bacillus subtilis, and Bacillus alcalophilus. An acid pulse technique was used to measure both parameters. The buffering capacity and membrane H+ conductance of B. alcalophilus are influenced by the pH of the medium and the culture conditions. Suspensions of B. alcalophilus cells from both H. A. medium and L-malate medium cultures grown at pH 10.5 exhibited higher values for these parameters than cells grown at pH 8.5. B. alcalophilus grown aerobically had a lower buffering capacity and a lower membrane conductance for protons than the neutrophilic bacteria S. aureus and B. subtilis. Fermenting cells exhibited significantly higher values for both variables than respiring cells. PMID:9546171

Rius, N; Lorén, J G

1998-04-01

86

Buffering Capacity and Membrane H+ Conductance of Neutrophilic and Alkalophilic Gram-Positive Bacteria  

PubMed Central

Buffering capacity and membrane H+ conductance were examined in three gram-positive bacteria, Staphylococcus aureus, Bacillus subtilis, and Bacillus alcalophilus. An acid pulse technique was used to measure both parameters. The buffering capacity and membrane H+ conductance of B. alcalophilus are influenced by the pH of the medium and the culture conditions. Suspensions of B. alcalophilus cells from both H. A. medium and l-malate medium cultures grown at pH 10.5 exhibited higher values for these parameters than cells grown at pH 8.5. B. alcalophilus grown aerobically had a lower buffering capacity and a lower membrane conductance for protons than the neutrophilic bacteria S. aureus and B. subtilis. Fermenting cells exhibited significantly higher values for both variables than respiring cells.

Rius, Nuria; Loren, Jose G.

1998-01-01

87

Update on antimicrobial susceptibility rates among gram-negative and gram-positive organisms in the United States: Results from the Tigecycline Evaluation and Surveillance Trial (TEST) 2005 to 2007  

Microsoft Academic Search

Background: The Tigecycline Evaluation and Surveillance Trial (TTEST) is a global surveillance study initiated in 2004.Its goal is to assess the in vitro activity of the glycylcycline, tigecycline, and comparator antimicrobials.Objective: The aim of this study was to measure the in vitro activity of a panel of antimicrobial agents against gram-nnegative and gram-ppositive organisms collected in the United States in

Michael J. Dowzicky; Choong H. Park

2008-01-01

88

Global control of sugar metabolism: a Gram-positive solution  

Microsoft Academic Search

Bacteria utilise carbon sources in a strictly controlled hierarchical manner for which they have developed global control mechanisms that govern and coordinate carbon source-specific regulation. This is achieved via carbon catabolite repression (CCR), which is the result of global transcriptional control and inducer exclusion. A common mechanism for transcriptional control has evolved within the group of low-GC Gram-positive bacteria, including

Fritz Titgemeyer; Wolfgang Hillen

2002-01-01

89

Identification of Gram-positive anaerobic cocci by MALDI-TOF mass spectrometry  

Microsoft Academic Search

Gram-positive anaerobic cocci (GPAC) are part of the commensal microbiota of humans and are a phylogenetically heterogeneous group of organisms. To evaluate the suitability of matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for the identification of GPAC, a database was constructed, using reference strains of commonly encountered GPAC and clinical isolates of which the sequence of the 16S rRNA

A. C. M. Veloo; M. Erhard; M. Welker; G. W. Welling; J. E. Degener

2011-01-01

90

Pharmacodynamics of Telavancin (TD6424), a Novel Bactericidal Agent, against Gram-Positive Bacteria  

Microsoft Academic Search

Telavancin (TD-6424) is a novel lipoglycopeptide that produces rapid and concentration-dependent killing of clinically relevant gram-positive organisms in vitro. The present studies evaluated the in vivo pharmaco- dynamics of telavancin in the mouse neutropenic thigh (MNT) and mouse subcutaneous infection (MSI) animal models. Pharmacokinetic-pharmacodynamic studies in the MNT model demonstrated that the 24-h area under the concentration-time curve (AUC)\\/MIC ratio

Sharath S. Hegde; Noe Reyes; Tania Wiens; Nicole Vanasse; Robert Skinner; Julia McCullough; K. Kaniga; J. Pace; R. Thomas; J.-P. Shaw; G. Obedencio; J. K. Judice

2004-01-01

91

Comparative genomics of the methionine metabolism in Gram-positive bacteria: a variety of regulatory systems.  

PubMed

Regulation of the methionine biosynthesis and transport genes in bacteria is rather diverse and involves two RNA-level regulatory systems and at least three DNA-level systems. In particular, the methionine metabolism in Gram-positive bacteria was known to be controlled by the S-box and T-box mechanisms, both acting on the level of premature termination of transcription. Using comparative analysis of genes, operons and regulatory elements, we described the methionine metabolic pathway and the methionine regulons in available genomes of Gram-positive bacteria. A large number of methionine-specific RNA elements were identified. S-boxes were shown to be widely distributed in Bacillales and Clostridia, whereas methionine-specific T-boxes occurred mostly in Lactobacillales. A candidate binding signal (MET-box) for a hypothetical methionine regulator, possibly MtaR, was identified in Streptococcaceae, the only family in the Bacillus/Clostridium group of Gram-positive bacteria having neither S-boxes, nor methionine-specific T-boxes. Positional analysis of methionine-specific regulatory sites complemented by genome context analysis lead to identification of new members of the methionine regulon, both enzymes and transporters, and reconstruction of the methionine metabolism in various bacterial genomes. In particular, we found candidate transporters for methionine (MetT) and methylthioribose (MtnABC), as well as new enzymes forming the S-adenosylmethionine recycling pathway. Methionine biosynthetic enzymes in various bacterial species are quite variable. In particular, Oceanobacillus iheyensis possibly uses a homolog of the betaine-homocysteine methyltransferase bhmT gene from vertebrates to substitute missing bacterial-type methionine synthases. PMID:15215334

Rodionov, Dmitry A; Vitreschak, Alexey G; Mironov, Andrey A; Gelfand, Mikhail S

2004-06-23

92

Discovery of 1,4-dihydroxy-2-naphthoate [corrected] prenyltransferase inhibitors: new drug leads for multidrug-resistant gram-positive pathogens.  

PubMed

Since utilization of menaquinone in the electron transport system is a characteristic of Gram-positive organisms, the 1,4-dihydroxy-2-naphthoate prenyltransferase (MenA) inhibitors 1a and 2a act as selective antibacterial agents against organisms such as methicillin-resistant Stapylococcus aureus (MRSA), Staphylococcus epidermidis (MRSE), and Mycobacterium spp. Growth of drug-resistant Gram-positive organisms was sensitive to the MenA inhibitors, indicating that menaquinone synthesis is a valid new drug target in Gram-positive organisms. PMID:17658779

Kurosu, Michio; Narayanasamy, Prabagaran; Biswas, Kallolmay; Dhiman, Rakesh; Crick, Dean C

2007-07-21

93

Microarray-Based Detection of 90 Antibiotic Resistance Genes of Gram-Positive Bacteria  

PubMed Central

A disposable microarray was developed for detection of up to 90 antibiotic resistance genes in gram-positive bacteria by hybridization. Each antibiotic resistance gene is represented by two specific oligonucleotides chosen from consensus sequences of gene families, except for nine genes for which only one specific oligonucleotide could be developed. A total of 137 oligonucleotides (26 to 33 nucleotides in length with similar physicochemical parameters) were spotted onto the microarray. The microarrays (ArrayTubes) were hybridized with 36 strains carrying specific antibiotic resistance genes that allowed testing of the sensitivity and specificity of 125 oligonucleotides. Among these were well-characterized multidrug-resistant strains of Enterococcus faecalis, Enterococcus faecium, and Lactococcus lactis and an avirulent strain of Bacillus anthracis harboring the broad-host-range resistance plasmid pRE25. Analysis of two multidrug-resistant field strains allowed the detection of 12 different antibiotic resistance genes in a Staphylococcus haemolyticus strain isolated from mastitis milk and 6 resistance genes in a Clostridium perfringens strain isolated from a calf. In both cases, the microarray genotyping corresponded to the phenotype of the strains. The ArrayTube platform presents the advantage of rapidly screening bacteria for the presence of antibiotic resistance genes known in gram-positive bacteria. This technology has a large potential for applications in basic research, food safety, and surveillance programs for antimicrobial resistance.

Perreten, Vincent; Vorlet-Fawer, Lorianne; Slickers, Peter; Ehricht, Ralf; Kuhnert, Peter; Frey, Joachim

2005-01-01

94

Gram-positive marine bacteria as a potential resource for the discovery of quorum sensing inhibitors.  

PubMed

Inhibitors of bacterial quorum sensing have been proposed as potentially novel therapeutics for the treatment of certain bacterial diseases. We recently reported a marine Halobacillus salinus isolate that secretes secondary metabolites capable of quenching quorum sensing phenotypes in several Gram-negative reporter strains. To investigate how widespread the production of such compounds may be in the marine bacterial environment, 332 Gram-positive isolates from diverse habitats were tested for their ability to interfere with Vibrio harveyi bioluminescence, a cell signaling-regulated phenotype. Rapid assay methods were employed where environmental isolates were propagated alongside the reporter strain. "Actives" were defined as bacteria that interfered with bioluminescence without visible cell-killing effects (antibiotic activity). A total of 49 bacterial isolates interfered with bioluminescence production in the assays. Metabolite extracts were generated from cultures of the active isolates, and 28 reproduced the bioluminescence inhibition against V. harveyi. Of those 28, five extracts additionally inhibited violacein production by Chromobacterium violaceum. Chemical investigations revealed that phenethylamides and a cyclic dipeptide are two types of secondary metabolites responsible for the observed activities. The active bacterial isolates belonged primarily to either the genus Bacillus or Halobacillus. The results suggest that Gram-positive marine bacteria are worthy of further investigation for the discovery of quorum sensing antagonists. PMID:21152942

Teasdale, Margaret E; Donovan, Kellye A; Forschner-Dancause, Stephanie R; Rowley, David C

2010-12-09

95

Synergist effect of sucrose fatty acid esters on nisin inhibition of gram-positive bacteria.  

PubMed

Nisin in combination with the sucrose fatty acid esters, sucrose palmitate (P-1570 and P-1670) or sucrose stearate (S-1570 and S-1670) was tested against a range of Gram-negative and Gram-positive bacteria. Initial liquid culture investigation showed that the sugar ester P-1670 resulted in a synergist enhancement of the bacteriostatic activity of nisin against Gram-positive bacteria and not Gram-negative bacteria. Some enhancement of the bactericidal activity of nisin against Listeria monocytogenes was also observed. This increased nisin inhibitory effect was confirmed on solid media using plates with gradients of pH and NaCl. Synergism was observed with all four sucrose fatty acid esters, which enhanced the antimicrobial activity of nisin against several strains of L. monocytogenes, Bacillus cereus (both cells and spores), Lactobacillus plantarum and Staphylococcus aureus. The combination of nisin and the sucrose fatty acid esters showed no inhibition of Gram-negative bacteria (Salmonella enteritidis, Salm. typhimurium and Pseudomonas aeruginosa). PMID:9871322

Thomas, L V; Davies, E A; Delves-Broughton, J; Wimpenny, J W

1998-12-01

96

Protochlorophyllide: a new photosensitizer for the photodynamic inactivation of Gram-positive and Gram-negative bacteria.  

PubMed

The growing resistance against antibiotics demands the search for alternative treatment strategies. Photodynamic therapy is a promising candidate. The natural intermediate of chlorophyll biosynthesis, protochlorophyllide, was produced, purified and tested as a novel photosensitizer for the inactivation of five model organisms including Staphylococcus aureus, Listeria monocytogenes and Yersinia pseudotuberculosis, all responsible for serious clinical infections. When microorganisms were exposed to white light from a tungsten filament lamp (0.1 mW cm(-2)), Gram-positive S. aureus, L. monocytogenes and Bacillus subtilis were photochemically inactivated at concentrations of 0.5 mg L(-1) protochlorophyllide. Transmission electron microscopy revealed a disordered septum formation during cell division and the partial loss of the cytoplasmic cell contents. Gram-negative Y. pseudotuberculosis and Escherichia coli were found to be insensitive to protochlorophyllide treatment due to the permeability barrier of the outer membrane. However, the two bacteria were rendered susceptible to eradication by protochlorophyllide (10 mg L(-1)) upon addition of polymyxin B nonapeptide at 50 and 20 mg L(-1), respectively. The release of DNA and a detrimental rearrangement of the cytoplasm were observed. PMID:19025572

Walther, Johannes; Bröcker, Markus J; Wätzlich, Denise; Nimtz, Manfred; Rohde, Manfred; Jahn, Dieter; Moser, Jürgen

2008-11-14

97

Special features of gram-positive bacterial eradication by photosensitizers.  

PubMed

Antibiotic resistance of pathogenic bacteria is a major concern and presents a special challenge for development of alternative antibacterial modalities. One of these alternative approaches is based on using the photodynamic therapy (PDT) for eradicating bacteria. Photosensitizer-induced PDT exhibits unique properties and demonstrates efficient microbe-killing effects. The efficient and irreversible antimicrobial effects of PDT are not dependent on the antibiotic susceptibility of the pathogenic bacteria to antibiotics. Gram-positive bacteria exhibit efficient binding of the photosensitizer to the bacterial barriers, leading to immediate photoinactivation of the bacteria. Photoinactivation of Gram-positive bacteria by various photosensitizers has become a high priority, since these bacteria are responsible for life-threatening infections in humans, especially in the elderly and in compromised hosts in whom they cause hospital-acquired infections. The present review concentrates on the photoinactivation of Staphylococi, Streptococci, Propionibacterium acnes, Deinococcus radiodurans, aerobic spore-forming Bacilli by various photosensitizers and by various methods described in numerous works and patents. PMID:23550546

Nitzan, Yeshayahu; Nisnevitch, Marina

2013-08-01

98

Gram-positive bacteria: an overview and summary of session.  

PubMed

The more pathogenic gram-positive bacteria present a complex array of surface structures to the human or animal host. The cell wall of Staphylococcus aureus has a pattern of surface proteins; the predominant one is protein A. Virulent S. aureus strains may also produce polysaccharide capsules in vivo that impede opsonization and phagocytosis in the absence of anticapsular antibody. Coagulase-negative staphylococci commonly elaborate an exopolysaccharide slime that may promote adherence to plastic surfaces and interfere with host responses. Structure-function relationships for some antiphagocytic M proteins of group A streptococci are now well understood, and recombinant techniques offer the prospect of multivalent vaccines. The best known surface protein of group B streptococci is the c (Ibc) protein, which stimulates protective antibody in animals and may be an important virulence factor. Monoclonal antibodies to types Ib, II, and III group B streptococci have also confirmed the presence of multiple immunodeterminants on these antiphagocytic polysaccharides. A protein on the surface of pneumococci has been shown to induce protective antibody and to enhance pneumococcal virulence in mice, suggesting a potential alternative or adjunct to pneumococcal polysaccharide vaccines. Listeria also possess a variety of cell surface structures important in pathogenesis. Surface components are, therefore, critical determinants of the interaction of gram-positive bacteria with the host. PMID:3055202

Anthony, B F; Hill, H R

99

Acyl-sulfamates Target the Essential Glycerol-Phosphate Acyltransferase (PlsY) in Gram-Positive Bacteria  

PubMed Central

PlsY is the essential first step in membrane phospholipid synthesis of Gram-positive pathogens. PlsY catalyzes the transfer of the fatty acid from acyl-phosphate to the 1-position of glycerol-3-phosphate to form the first intermediate in membrane biogenesis. A series of non-metabolizable, acyl-sulfamate analogs of the acyl-phosphate PlsY substrate were prepared and evaluated as inhibitors of Staphylococcus aureus PlsY and for their Gram-positive antibacterial activities. From this series phenyl (8-phenyloctanoyl) sulfamate had the best overall profile, selectively inhibiting S. aureus phospholipid biosynthesis and causing the accumulation of both long-chain fatty acids and acyl-acyl carrier protein intermediates demonstrating that PlsY was the primary cellular target. Bacillus anthracis was unique in being more potently inhibited by long chain acyl-sulfamates than other bacterial species. However, it is shown that Bacillus anthracis PlsY is not more sensitive to the acyl-sulfamates than S. aureus PlsY. Metabolic profiling showed that B. anthracis growth inhibition by the acyl-sulfamates was not specific for lipid synthesis illustrating that the amphipathic acyl-sulfamates can also have off-target effects in Gram-positive bacteria. Nonetheless, this study further advances PlsY as a druggable target for the development of novel antibacterial therapeutics, through the discovery and validation of the probe compound phenyl (8-phenyloctanoyl) sulfamate as a S. aureus PlsY inhibitor.

Cherian, Philip; Yao, Jiangwei; Leonardi, Roberta; Maddox, Marcus M.; Luna, Vicki A.; Rock, Charles O.; Lee, Richard E.

2012-01-01

100

Acyl-sulfamates target the essential glycerol-phosphate acyltransferase (PlsY) in Gram-positive bacteria.  

PubMed

PlsY is the essential first step in membrane phospholipid synthesis of Gram-positive pathogens. PlsY catalyzes the transfer of the fatty acid from acyl-phosphate to the 1-position of glycerol-3-phosphate to form the first intermediate in membrane biogenesis. A series of non-metabolizable, acyl-sulfamate analogs of the acyl-phosphate PlsY substrate were prepared and evaluated as inhibitors of Staphylococcus aureus PlsY and for their Gram-positive antibacterial activities. From this series phenyl (8-phenyloctanoyl) sulfamate had the best overall profile, selectively inhibiting S. aureus phospholipid biosynthesis and causing the accumulation of both long-chain fatty acids and acyl-acyl carrier protein intermediates demonstrating that PlsY was the primary cellular target. Bacillus anthracis was unique in being more potently inhibited by long chain acyl-sulfamates than other bacterial species. However, it is shown that Bacillus anthracis PlsY is not more sensitive to the acyl-sulfamates than S. aureus PlsY. Metabolic profiling showed that B. anthracis growth inhibition by the acyl-sulfamates was not specific for lipid synthesis illustrating that the amphipathic acyl-sulfamates can also have off-target effects in Gram-positive bacteria. Nonetheless, this study further advances PlsY as a druggable target for the development of novel antibacterial therapeutics, through the discovery and validation of the probe compound phenyl (8-phenyloctanoyl) sulfamate as a S. aureus PlsY inhibitor. PMID:22795901

Cherian, Philip T; Yao, Jiangwei; Leonardi, Roberta; Maddox, Marcus M; Luna, Vicki A; Rock, Charles O; Lee, Richard E

2012-06-23

101

Effect of Hematin on the Recovery of Bacillus Anthracis and Related Organisms.  

National Technical Information Service (NTIS)

The results indicate that freshly prepared alkaline hematin solution is inhibitory for many gram-positive organisms, including B. anthracis; therefore, its use in a selective medium for the isolation of B. anthracis is questionable. However, freshly prepa...

R. F. Knisely

1964-01-01

102

Fate study of water-borne gram positive vegetative bacterial cells with Raman microscopy  

NASA Astrophysics Data System (ADS)

We present an initial bacterial fate study of Gram positive vegetative cells suspended in water and stored at ambient room temperature via Raman spectroscopy monitoring. Two types of cells were considered for this study: vegetative cells of Bacillus cereus, Bacillus thuringiensis which contain the polyhydroxybutyric acid (PHBA) as an energy storage compound and Bacillus subtlilis cells which do not. The cells were cultured specifically for this project. Immediately following the culturing phase, the bacteria were extracted, cleaned and at the onset of the study were suspended in de-ionized water and stored at room temperature. Aliquots of suspensions were deposited onto aluminum slides at different times and allowed to dry for Raman analysis. Spectra from multiple regions of each dried spot and each deposit time were acquired along with the bright-field and fluorescence images. Results were examined to investigate the effect of suspension time on the spectral signatures as well as the fate behavior of the three types of cells investigated. The cells were monitored daily for over a 14 period during which time the onset of starvation induced sporulation was observed.

Guicheteau, Jason; Tripathi, Ashish; Minter, Jennifer; Wilcox, Phillip; Christesen, Steven

2010-04-01

103

In Silico Evidence for the Horizontal Transfer of gsiB, a ??-Regulated Gene in Gram-Positive Bacteria, to Lactic Acid Bacteria ?  

PubMed Central

gsiB, coding for glucose starvation-inducible protein B, is a characteristic member of the ?? stress regulon of Bacillus subtilis and several other Gram-positive bacteria. Here we provide in silico evidence for the horizontal transfer of gsiB in lactic acid bacteria that are devoid of the ?? factor.

Asteri, Ioanna-Areti; Boutou, Effrossyni; Anastasiou, Rania; Pot, Bruno; Vorgias, Constantinos E.; Tsakalidou, Effie; Papadimitriou, Konstantinos

2011-01-01

104

Isolation and characterization of four novel Gram-positive bacteria associated with the rhizosphere of two endemorelict plants capable of degrading a broad range of aromatic substrates  

Microsoft Academic Search

Four new Gram-positive, phenol-degrading strains were isolated from the rhizospheres of endemorelict plants Ramonda serbica and Ramonda nathaliae known to exude high amounts of phenolics in the soil. Isolates were designated Bacillus sp. PS1, Bacillus sp. PS11, Streptomyces sp. PS12, and Streptomyces sp. PN1 based on 16S rDNA sequence and biochemical analysis. In addition to their ability to tolerate and

Lidija Djokic; Tanja Narancic; Jasmina Nikodinovic-Runic; Miloje Savic; Branka Vasiljevic

2011-01-01

105

Coordinate regulation of Gram-positive cell surface components  

PubMed Central

The cell surface of Gram-positive pathogens represents a complex association of glycopolymers that control cell division, homeostasis, immune evasion, tissue invasion, and resistance to antimicrobials. These glycopolymers include the peptidoglycan cell wall, wall-teichoic acids, lipoteichoic acids, and capsular polysaccharide. Disruption of individual factors often results in pleiotropic effects, making it difficult to discern regulation and function. In this review we collate recent work describing these pleiotropic phenotypes, and propose that this is due to coordinated regulation of biosynthesis or modification of these cell surface components. A better understanding of the regulatory networks that control the relative prevalence of each factor on the cell surface or their modulated functions may help facilitate the identification of new targets for antimicrobial therapy.

Hanson, Brett R.; Neely, Melody N.

2012-01-01

106

InVitro Activities ofTwoGlycylcyclines against Gram-Positive Bacteria  

Microsoft Academic Search

derivatives of minocycline and6-demethyl-6-deoxytetracycline, respectively. Invitro activities of these twoantimicrobial agents werecompared withthose oftetracycline, minocycline, andseven other antimicrobial agents against 412 gram-positive organisms. Bothnewdrugs weresignificantly moreactive thanminocycline against methicillin- resistant Staphylococcus aureus (MICsfor90%o ofisolates tested, 0.25and0.5,ug\\/ml versus 4pg\\/ml). CL 329,998 inhibited allstreptococci, lactobacilli, andLeuconostoc spp. atconcentrations of<0.5,ug\\/ml, withCL 331,002 slightly lessactive against somespecies. Allenterococci, including minocycline-resistant and multidrug-resistant isolates, wereinhibited

G. M. ELIOPOULOS; C. B. WENNERSTEN; G. COLE; C. MOELLERING

1994-01-01

107

Introduction and reisolation of selected gram-positive bacteria from fermented edible wastes.  

PubMed

A fermentation process using Lactobacillus acidophilus added to edible food wastes was evaluated for its bactericidal action on selected gram-positive organisms. The Lactobacillus fermentation converts food wastes into an animal feed ingredient. In this study, 5 gram-positive bacteria of zoonotic importance were individually tested. These organisms were: Group E Streptococcus, Erysipelothrix rhusiopathiae, Clostridium perfringens, Corynebacterium pseudotuberculosis, and Listeria monocytogenes. For each experiment, Lactobacillus was first mixed into ground waste; one of the test organisms was then inoculated and mixed. This mixture was divided among eight 5.5-L containers and incubated (duplicates) at 5 C, 10 C, 20 C, and 30 C for 96 hours. Internal waste temperature, reduction-oxidation, and pH were monitored. Waste samples were taken initially and at subsequent 24-hour periods. Qualitative and quantitative recoveries of the test bacteria were attempted for each sample. Group E Streptococcus was reisolated in increasing numbers at all temperatures throughout the fermentation period. Erysipelothrix rhusiopathiae was recovered throughout the 96-hour period at 5 C; at 10 C it was recovered at 24 hours but not at 48 hours. Erysipelothrix rhusiopathiae was killed by 24 hours at 20 C and 30 C fermentation temperatures. Clostridium perfringens survived the entire test period at 5 C, 10 C, and 20 C; it was killed by 72 hours at 30 C. Neither Corynebacterium pseudotuberculosis nor Listeria monocytogenes was reisolated at any temperature at any time. PMID:6271028

Talkington, F D; Shotts, E B; Wooley, R E; Whitehead, W K; Dobbins, C N

1981-08-01

108

Influence of bentonite particles on representative gram negative and gram positive bacterial deposition in porous media.  

PubMed

The significance of clay particles on the transport and deposition kinetics of bacteria in irregular quartz sand was examined by direct comparison of both breakthrough curves and retained profiles with clay particles in bacteria suspension versus those without clay particles. Two representative cell types, Gram-negative strain E. coli DH5? and Gram-positive strain Bacillus subtilis were utilized to systematically determine the influence of clay particles (bentonite) on cell transport behavior. Packed column experiments for both cell types were conducted in both NaCl (5 and 25 mM ionic strengths) and CaCl(2) (5 mM ionic strength) solutions at pH 6.0. The breakthrough plateaus with bentonite in solutions (30 mg L(-1) and 50 mg L(-1)) were lower than those without bentonite for both cell types under all examined conditions, indicating that bentonite in solutions decreased cell transport in porous media regardless of cell types (Gram-negative or Gram-positive) and solution chemistry (ionic strength and ion valence). The enhanced cell deposition with bentonite particles was mainly observed at segments near to column inlet, retained profiles for both cell types with bentonite particles were therefore steeper relative to those without bentonite. The increased cell deposition with bentonite observed in NaCl solutions was attributed to the codeposition of bacteria with bentonite particles whereas, in addition to codeposition of bacteria with bentonite, the bacteria-bentonite-bacteria cluster formed in suspensions also contributed to the increased deposition of bacteria with bentonite in CaCl(2) solution. PMID:22970735

Yang, Haiyan; Tong, Meiping; Kim, Hyunjung

2012-10-09

109

Vancomycin-resistant gram-positive cocci isolated from the saliva of wild songbirds.  

PubMed

We analyzed highly vancomycin-resistant Gram-positive bacteria isolated from the saliva of migratory songbirds captured, sampled, and released from a bird-banding station in western Kansas. Individual bacterial isolates were identified by partial 16S rRNA sequencing. Most of the bacteria in this study were shown to be Staphylococcus succinus with the majority being isolated from the American Robin. Some of these bacteria were shown to carry vanA, vanB, and vanC vancomycin-resistance genes and have the ability to form biofilms. One of the van gene-carrying isolates is also coagulase positive, which is normally considered a virulence factor. Other organisms isolated included Staphylococcus saprophyticus as well as Enterococcus gallinarum. Given the wide range of the American Robin and ease of horizontal gene transfer between Gram-positive cocci, we postulate that these organisms could serve as a reservoir of vancomycin-resistance genes capable of transferring to human pathogens. PMID:23224296

Ishihara, Shingo; Bitner, Jessica J; Farley, Greg H; Gillock, Eric T

2012-12-06

110

Characterization of a pyridine-degrading branched Gram-positive bacterium isolated from the anoxic zone of an oil shale column  

Microsoft Academic Search

From the anoxic zone of an oil shale leachate column three pyridine-degrading bacterial strains were isolated. Two strains were Gram-negative facultative anaerobic rods and one strain was a branched Gram-positive bacterium. The branched Gram-positive strain had the best pyridine-degrading ability. This organism was aerobic, non-motile, catalase positive, oxidase negative, and had no flagellum. The G+C content of the DNA was

Sung-Taik Lee; Seung-Bong Lee; Yong-Ha Park

1991-01-01

111

A Comparison of the Staining Reactions of the Cell Walls of Azotobacter chroococcum and those of Gram-positive and Gram-negative Bacteria  

Microsoft Academic Search

SUMMARY: The effects of various reagents in the mordanting and staining of bacterial cell wab are described, The cell walls of Gram-positive bacteria were found to be much more readily stainable than those of Gram-negative organisms. In this and other respects, apart from the Gram reaction Azotobacter chroococcum resembled a Gram-positive species; some of the methods described provided an excellent

C. M. F. HALE; K. A. BISSET

1956-01-01

112

Relevance of GC content to the conservation of DNA polymerase III/mismatch repair system in Gram-positive bacteria  

PubMed Central

The mechanism of DNA replication is one of the driving forces of genome evolution. Bacterial DNA polymerase III, the primary complex of DNA replication, consists of PolC and DnaE. PolC is conserved in Gram-positive bacteria, especially in the Firmicutes with low GC content, whereas DnaE is widely conserved in most Gram-negative and Gram-positive bacteria. PolC contains two domains, the 3?-5?exonuclease domain and the polymerase domain, while DnaE only possesses the polymerase domain. Accordingly, DnaE does not have the proofreading function; in Escherichia coli, another enzyme DnaQ performs this function. In most bacteria, the fidelity of DNA replication is maintained by 3?-5? exonuclease and a mismatch repair (MMR) system. However, we found that most Actinobacteria (a group of Gram-positive bacteria with high GC content) appear to have lost the MMR system and chromosomes may be replicated by DnaE-type DNA polymerase III with DnaQ-like 3?-5? exonuclease. We tested the mutation bias of Bacillus subtilis, which belongs to the Firmicutes and found that the wild type strain is AT-biased while the mutS-deletant strain is remarkably GC-biased. If we presume that DnaE tends to make mistakes that increase GC content, these results can be explained by the mutS deletion (i.e., deletion of the MMR system). Thus, we propose that GC content is regulated by DNA polymerase and MMR system, and the absence of polC genes, which participate in the MMR system, may be the reason for the increase of GC content in Gram-positive bacteria such as Actinobacteria.

Akashi, Motohiro; Yoshikawa, Hirofumi

2013-01-01

113

Relevance of GC content to the conservation of DNA polymerase III/mismatch repair system in Gram-positive bacteria.  

PubMed

The mechanism of DNA replication is one of the driving forces of genome evolution. Bacterial DNA polymerase III, the primary complex of DNA replication, consists of PolC and DnaE. PolC is conserved in Gram-positive bacteria, especially in the Firmicutes with low GC content, whereas DnaE is widely conserved in most Gram-negative and Gram-positive bacteria. PolC contains two domains, the 3'-5'exonuclease domain and the polymerase domain, while DnaE only possesses the polymerase domain. Accordingly, DnaE does not have the proofreading function; in Escherichia coli, another enzyme DnaQ performs this function. In most bacteria, the fidelity of DNA replication is maintained by 3'-5' exonuclease and a mismatch repair (MMR) system. However, we found that most Actinobacteria (a group of Gram-positive bacteria with high GC content) appear to have lost the MMR system and chromosomes may be replicated by DnaE-type DNA polymerase III with DnaQ-like 3'-5' exonuclease. We tested the mutation bias of Bacillus subtilis, which belongs to the Firmicutes and found that the wild type strain is AT-biased while the mutS-deletant strain is remarkably GC-biased. If we presume that DnaE tends to make mistakes that increase GC content, these results can be explained by the mutS deletion (i.e., deletion of the MMR system). Thus, we propose that GC content is regulated by DNA polymerase and MMR system, and the absence of polC genes, which participate in the MMR system, may be the reason for the increase of GC content in Gram-positive bacteria such as Actinobacteria. PMID:24062730

Akashi, Motohiro; Yoshikawa, Hirofumi

2013-09-17

114

Novel bacterial lipoprotein structures conserved in low-GC content gram-positive bacteria are recognized by Toll-like receptor 2.  

PubMed

Bacterial lipoproteins/lipopeptides inducing host innate immune responses are sensed by mammalian Toll-like receptor 2 (TLR2). These bacterial lipoproteins are structurally divided into two groups, diacylated or triacylated lipoproteins, by the absence or presence of an amide-linked fatty acid. The presence of diacylated lipoproteins has been predicted in low-GC content gram-positive bacteria and mycoplasmas based on the absence of one modification enzyme in their genomes; however, we recently determined triacylated structures in low-GC gram-positive Staphylococcus aureus, raising questions about the actual lipoprotein structure in other low-GC content gram-positive bacteria. Here, through intensive MS analyses, we identified a novel and unique bacterial lipoprotein structure containing an N-acyl-S-monoacyl-glyceryl-cysteine (named the lyso structure) from low-GC gram-positive Enterococcus faecalis, Bacillus cereus, Streptococcus sanguinis, and Lactobacillus bulgaricus. Two of the purified native lyso-form lipoproteins induced proinflammatory cytokine production from mice macrophages in a TLR2-dependent and TLR1-independent manner but with a different dependence on TLR6. Additionally, two other new lipoprotein structures were identified. One is the "N-acetyl" lipoprotein structure containing N-acetyl-S-diacyl-glyceryl-cysteine, which was found in five gram-positive bacteria, including Bacillus subtilis. The N-acetyl lipoproteins induced the proinflammatory cytokines through the TLR2/6 heterodimer. The other was identified in a mycoplasma strain and is an unusual diacyl lipoprotein structure containing two amino acids before the lipid-modified cysteine residue. Taken together, our results suggest the existence of novel TLR2-stimulating lyso and N-acetyl forms of lipoproteins that are conserved in low-GC content gram-positive bacteria and provide clear evidence for the presence of yet to be identified key enzymes involved in the bacterial lipoprotein biosynthesis. PMID:22303020

Kurokawa, Kenji; Ryu, Kyoung-Hwa; Ichikawa, Rie; Masuda, Akiko; Kim, Min-Su; Lee, Hanna; Chae, Jun-Ho; Shimizu, Takashi; Saitoh, Tatsuya; Kuwano, Koichi; Akira, Shizuo; Dohmae, Naoshi; Nakayama, Hiroshi; Lee, Bok Luel

2012-02-02

115

Novel Bacterial Lipoprotein Structures Conserved in Low-GC Content Gram-positive Bacteria Are Recognized by Toll-like Receptor 2*  

PubMed Central

Bacterial lipoproteins/lipopeptides inducing host innate immune responses are sensed by mammalian Toll-like receptor 2 (TLR2). These bacterial lipoproteins are structurally divided into two groups, diacylated or triacylated lipoproteins, by the absence or presence of an amide-linked fatty acid. The presence of diacylated lipoproteins has been predicted in low-GC content Gram-positive bacteria and mycoplasmas based on the absence of one modification enzyme in their genomes; however, we recently determined triacylated structures in low-GC Gram-positive Staphylococcus aureus, raising questions about the actual lipoprotein structure in other low-GC content Gram-positive bacteria. Here, through intensive MS analyses, we identified a novel and unique bacterial lipoprotein structure containing an N-acyl-S-monoacyl-glyceryl-cysteine (named the lyso structure) from low-GC Gram-positive Enterococcus faecalis, Bacillus cereus, Streptococcus sanguinis, and Lactobacillus bulgaricus. Two of the purified native lyso-form lipoproteins induced proinflammatory cytokine production from mice macrophages in a TLR2-dependent and TLR1-independent manner but with a different dependence on TLR6. Additionally, two other new lipoprotein structures were identified. One is the “N-acetyl” lipoprotein structure containing N-acetyl-S-diacyl-glyceryl-cysteine, which was found in five Gram-positive bacteria, including Bacillus subtilis. The N-acetyl lipoproteins induced the proinflammatory cytokines through the TLR2/6 heterodimer. The other was identified in a mycoplasma strain and is an unusual diacyl lipoprotein structure containing two amino acids before the lipid-modified cysteine residue. Taken together, our results suggest the existence of novel TLR2-stimulating lyso and N-acetyl forms of lipoproteins that are conserved in low-GC content Gram-positive bacteria and provide clear evidence for the presence of yet to be identified key enzymes involved in the bacterial lipoprotein biosynthesis.

Kurokawa, Kenji; Ryu, Kyoung-Hwa; Ichikawa, Rie; Masuda, Akiko; Kim, Min-Su; Lee, Hanna; Chae, Jun-Ho; Shimizu, Takashi; Saitoh, Tatsuya; Kuwano, Koichi; Akira, Shizuo; Dohmae, Naoshi; Nakayama, Hiroshi; Lee, Bok Luel

2012-01-01

116

Murine model of cutaneous infection with gram-positive cocci.  

PubMed Central

Staphylococcus aureus has remained an important cause of nosocomial wound infections, but standardized or reproducible systems for analyzing cutaneous infections caused by S. aureus do not exist. A variety of foreign materials, variable inocula, and skin traumas have been used to promote infection. To minimize these variables and ensure reproducibility, we chose a model using subcutaneous injections of a fixed quantity of dextran microbeads (Cytodex) as the foreign material added to standardized broth suspensions of S. aureus. Suspensions (0.2 ml) injected into an outbred strain of immunocompetent hairless mice generated reproducible, measurable lesions. With S. aureus Smith Diffuse, fluctuant, erythematous lesions with a peak diameter of 15 mm were observed; these lesions yielded purulent material containing gram-positive cocci and neutrophils and yielded growth of S. aureus on culture. Lesion size was proportional to the bacterial inoculum size. Histologic examination of excised lesions revealed typical abscesses. A second strain of S. aureus (SLC3) produced dermonecrosis instead of abscesses at an inoculum size of 10(7) CFU. Control injections with a sterile Cytodex suspension regularly produced nondraining, nonerythematous nodules with maximum diameters of less than or equal to 5 mm. Streptococcus pyogenes produced late-onset necrotic lesions and abscesses. Using a foreign substance, this model generates easily observed and reproducible cutaneous infection with S. aureus and streptococci that can potentially discriminate between inter- and intrastrain differences. Such a model could be used to test the pathogenicity of isogeneic strains of these bacterial species and to evaluate the efficacy of antimicrobial agents. Images

Bunce, C; Wheeler, L; Reed, G; Musser, J; Barg, N

1992-01-01

117

Activity of glycopeptides against vancomycin-resistant gram-positive bacteria.  

PubMed Central

Gram-positive bacteria resistant to vancomycin are rare; but they include members of the genera Leuconostoc, Lactobacillus, and Pediococcus, as well as recently emerging vancomycin-resistant strains of Enterococcus faecium and Enterococcus faecalis. Vancomycin, teicoplanin, and several vancomycin derivatives were tested for their activities against vancomycin-resistant gram-positive bacteria. Vancomycin-resistant E. faecium and E. faecalis were generally cross-resistant to other glycopeptides, but some N-substituted vancomycin derivatives were active against the resistant strains, with MICs of 2 to 32 micrograms/ml. These vancomycin derivatives also had significant levels of activity against intrinsically vancomycin-resistant organisms such as Leuconostoc sp. While vancomycin resistance in E. faecium and E. faecalis was inducible, resistance in members of the genera Leuconostoc, Lactobacillus, and Pediococcus appeared to be expressed constitutively. Antibody to a vancomycin-induced membrane protein found in membranes of resistant enterococci did not detect a cross-reacting protein in other vancomycin-resistant species.

Nicas, T I; Cole, C T; Preston, D A; Schabel, A A; Nagarajan, R

1989-01-01

118

Thermophilic Gram-Positive Biocatalysts for Biomass Conversion to Ethanol  

SciTech Connect

Production of energy from renewable sources is receiving increased attention due to the finite nature of fossil fuels and the environmental impact associated with the continued large scale use of fossil energy sources. Biomass, a CO2-neutral abundant resource, is an attractive alternate source of energy. Biomass-derived sugars, such as glucose, xylose, and other minor sugars, can be readily fermented to fuel ethanol and commodity chemicals. Extracellular cellulases produced by fungi are commercially developed for depolymerization of cellulose in biomass to glucose for fermentation by appropriate biocatalysts in a simultaneous saccharification and fermentation (SSF) process. Due to the differences in the optimum conditions for the activity of the fungal cellulases and the growth and fermentation characteristics of the current industrial biocatalysts, SSF of cellulose is envisioned at conditions that are not optimal for the fungal cellulase activity leading to higher than required cost of cellulase in SSF. We have isolated bacterial biocatalysts whose growth and fermentation requirements match the optimum conditions for commercial fungal cellulase activity (pH 5.0 and 50 deg. C). These isolates fermented both glucose and xylose, major components of cellulose and hemicellulose, respectively, to L(+)-lactic acid. Xylose was metabolized through the pentose-phosphate pathway by these organisms as evidenced by the fermentation profile and analysis of the fermentation products of 13C1-xylose by NMR. As expected for the metabolism of xylose by the pentose-phosphate pathway, 13C-lactate accounted for more than 90% of the total 13C-labeled products. All three strains fermented crystalline cellulose to lactic acid with the addition of fungal cellulase (Spezyme CE) (SSF) at an optimum of about 10 FPU/g cellulose. These isolates also fermented cellulose and sugar cane bagasse hemicellulose acid hydrolysate simultaneously. Based on fatty acid profile and 16S rRNA sequence, these isolates cluster with Bacillus coagulans although B. coagulans type strain, ATCC 7050, failed to utilize xylose as a carbon source. For successful production of ethanol from pyruvate, both pyruvate decarboxylase (PDC) and alcohol dehydrogenase (AHD) need to be produced at optimal levels in these biocatalysts. A plasmid containing the S. ventriculi pdc gene and the adh gene from geobacillus stearothermophilus was constructed using plasmid pWH1520 that was successfully used for expression of pdc in B. megaterium. The resulting portable ethanol (PET) plasmid, pJAM423, was transformed into B. megaterium. After xylose induction, a significant fraction of cell cytoplasm was composed of the S. ventriculi PDC and G. stearothermophilus ADH proteins. In preliminary experiments, the amount of ethanol produced by b. megaterium with plasmid pJAM423 was about twice (20 mM) of the bacterium without the plasmid. These results show that the PET operon is functional in B. megaterium but high level ethanol production needs further genetic and metabolic engineering. A genetic transfer system for the second generation biocatalysts needs to be developed for transferring the plasmid pJAM423 and its derivatives for engineering these organisms for ethanol production from biomass derived sugars and cellulose to ethanol. One of the new biocatalysts, strain P4-102B was found to be transformable with plasmids and the method for introducing plasmid pJAM423 into this strain and expression of the encoded DNA is being optimized. These new second generation biocatalysts have the potential to reduce the cost of SSF by minimizing the amount of fungal cellulases, a significant cost component in the use of biomass as a renewable resource for production of fuels and chemicals.

Shanmugam, K.T.; Ingram, L.O.; Maupin-Furlow, J.A.; Preston, J.F.; Aldrich, H.C.

2003-12-01

119

Lipoteichoic Acid Is Important in Innate Immune Responses to Gram-Positive Bacteria  

Microsoft Academic Search

To define the role of lipoteichoic acid (LTA) in innate immunity to gram-positive bacteria, we investigated the production of tumor necrosis factor alpha (TNF-) by macrophages stimulated with gram-positive bac- terial culture supernatants (GPCSs) after their LTA was removed or inactivated. GPCSs were obtained from three gram-positive species (pneumococci, staphylococci, and group B streptococci) during the exponential growth phase (designated

Ho Seong Seo; Suzanne M. Michalek; Moon H. Nahm

2008-01-01

120

BACILLUS sp. SUSLARINDA ANT?B?YOT?K , SELULAZ VE AM?LAZ ÜRETIM?NDEN SORUMLU GENLER?N PROTOPLAST TRANSFORMASYON TEKN??? ?LE Gr(+) BAKTER?LERE TRANSFER? VE EKSPRESYON DÜZEY?N?N ARA?TIRILMASI* The Genes That Responsible Of Antibiotic, Cellulase And Amylase Production Of Bacillus sp. Transfer To Gram-Positive Bacteria By Using Protoplast Transformation Technique And Investigation Of The Expression Level  

Microsoft Academic Search

We tested amylase, cellulase and antibiotic activites of Bacillus sp., which were izolated from different locations. We examined after acridine orange elimination of amylase, cellulase and antibiotic effectivity positive strains, whether the gene responsible for this activity encoded plasmid. We didn't determine any straine including plasmid encoded genetic markers. We also isolated chromosomal DNA from Bacillus sp. which were carried

Özlem EREN; Burhan ARIKAN

121

Antibacterial activity of oregano (Origanum vulgare Linn.) against gram positive bacteria.  

PubMed

The present investigation is focused on antibacterial potential of infusion, decoction and essential oil of oregano (Origanum vulgare) against 111 Gram-positive bacterial isolates belonging to 23 different species related to 3 genera. Infusion and essential oil exhibited antibacterial activity against Staphylococcus saprophyticus, S. aureus, Micrococcus roseus, M. kristinae, M. nishinomiyaensis, M. lylae, M. luteus, M. sedentarius, M. varians, Bacillus megaterium, B. thuringiensis, B. alvei, B. circulans, B. brevis, B. coagulans, B. pumilus, B. laterosporus, B. polymyxa, B. macerans, B. subtilis, B. firmus, B. cereus and B. lichiniformis. The infusion exhibited maximum activity against B. laterosporus (17.5 mm mean zone of inhibition+/-1.5 Standard deviation) followed by B. polymyxa (17.0 mm+/-2.0 SD) and essential oil of oregano exhibited maximum activity against S. saprophyticus (16.8 mm+/-1.8 SD) followed by B. circulans (14.5 mm+/-0.5 SD). While all these tested isolates were found resistant to decoction of oregano. PMID:19783523

Saeed, Sabahat; Tariq, Perween

2009-10-01

122

Genetic features of circular bacteriocins produced by Gram-positive bacteria.  

PubMed

This review highlights the main genetic features of circular bacteriocins, which require the co-ordinated expression of several genetic determinants. In general terms, it has been demonstrated that the expression of such structural genes must be combined with the activity of proteins involved in maturation (cleavage/circularization) and secretion outside the cell via different transporter systems, as well as multifaceted immunity mechanisms essential to ensuring the bacteria's self-protection against such strong inhibitors. Several circular antibacterial peptides produced by Gram-positive bacteria have been described to date, including enterocin AS-48, from Enterococcus faecalis S-48 (the first one characterized), gassericin A, from Lactobacillus gasseri LA39, and a similar one, reutericin 6, from Lactobacillus reuteri LA6, butyrivibriocin AR10, from the ruminal anaerobe Butyrivibrio fibrisolvens AR10, uberolysin, from Streptococcus uberis, circularin A, from Clostridium beijerinckii ATCC 25752, and subtilosin A, from Bacillus subtilis. We summarize here the progress made in the understanding of their principal genetic features over the last few years, during which the functional roles of circular proteins with wide biological activity have become clearer. PMID:18034824

Maqueda, Mercedes; Sánchez-Hidalgo, Marina; Fernández, Matilde; Montalbán-López, Manuel; Valdivia, Eva; Martínez-Bueno, Manuel

2007-11-20

123

Periodic acid-Schiff-positive organisms in primary cutaneous Bacillus cereus infection. Case report and an investigation of the periodic acid-Schiff staining properties of bacteria.  

PubMed

Primary cutaneous Bacillus cereus infection frequently presents as a single necrotic bulla on the extremity of an immunocompromised patient. In lesional biopsy specimens and smears, the large gram-positive rods of B cereus may be mistaken for Clostridium species. This is a potentially serious error, as Bacillus species are resistant to penicillin and other beta-lactam antibiotics. We studied a case in which large periodic acid-Schiff-staining organisms were seen in the biopsy specimen from a necrotic bulla on the finger of a neutropenic patient with diffuse large cell lymphoma. The tissue biopsy specimen subsequently yielded a pure culture of B cereus. Staining with periodic acid-Schiff was then performed on a series of bacterial species in human tissue and from smears of culture colonies. The following bacterial species were found to be consistently periodic acid-Schiff positive after diastase digestion: B cereus, Corynebacterium diphtheriae, Propionibacterium acnes, Klebsiella pneumoniae, and Micrococcus luteus. PMID:1900984

Khavari, P A; Bolognia, J L; Eisen, R; Edberg, S C; Grimshaw, S C; Shapiro, P E

1991-04-01

124

Antimicrobial Susceptibilities ofCorynebacteriumSpecies and Other Non-Spore-Forming Gram-Positive Bacilli to 18 Antimicrobial Agents  

Microsoft Academic Search

The susceptibilities of 265 strains of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobial agents were tested. Most strains were susceptible to vancomycin, doxycycline, and fusidic acid. Corynebacterium jeikeium and Corynebacterium urealyticum were the most resistant organisms tested. Resistance to b-lactams, clindamycin, erythromycin, azythromycin, ciprofloxacin and gentamicin was common among strains of Corynebacterium xerosis and Corynebacterium minutissimum. Ampicillin

FRANCISCO SORIANO; JAVIER ZAPARDIEL; ANDEVA NIETO

125

Computational identification of the Spo0A-phosphate regulon that is essential for the cellular differentiation and development in Gram-positive spore-forming bacteria  

Microsoft Academic Search

Spo0A-phosphate is essential for the initiation of cellular differentiation and developmental pro- cesses in Gram-positive spore-forming bacteria. Here we combined comparative genomics with analyses of microarray expression profiles to iden- tify the Spo0A-phosphate regulon in Bacillus subti- lis. The consensus Spo0A-phosphate DNA-binding motif identified from the training set based on differ- ent computational algorithms is an 8 bp sequence, TTGTCGAA.

Jiajian Liu; Kai Tan; Gary D. Stormo

2003-01-01

126

Chemical analysis of isolated cell walls of Gram-positive bacteria and determination of the cell wall to cell mass ratio  

Microsoft Academic Search

Cell walls of five Gram-positive bacterial strains, including four coryneforms and a Bacillus brevis strain were isolated and subsequently chemically analysed. The wall contribution to the total cell mass is calculated from a comparison of d-Lactate concentrations in hydrolysates of whole cells and isolated walls. d-Lactate concentrations are measured enzymatically after purification of the samples with active carbon. The optimum

Albert van der Wal; Willem Norde; Bernd Bendinger; Alexander J. B Zehnder; Johannes Lyklema

1997-01-01

127

Use of the lactococcal nisA promotor to regulate gene expression in gram-positive bacteria: comparison of induction level and promotor strength  

Microsoft Academic Search

We characterized the regulated activity of the lactococcal nisA promoter in strains of the gram-positive species Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, Enterococcus faecalis, and Bacillus subtilis. nisA promoter activity was dependent on the proteins NisR and NisK, which constitute a two-component signal transduction system that responds to the extracellular inducer nisin. The nisin sensitivity and inducer concentration required for

Zehava Eichenbaum; Michael J. Federle; Diana Marra; Willem M. de Vos; Oscar P. Kuipers; Michiel Kleerebezem; June R. Scott

1998-01-01

128

Clinical experience with linezolid in the treatment of resistant gram-positive infections.  

PubMed Central

This study presents our clinical experience with linezolid in 19 patients with serious resistant gram-positive infections enrolled as part of the compassionate study. In this prospective, non-randomized, noncomparative study, 19 patients were enrolled as part of the National Compassionate Study Protocol conducted by Pharmacia-Upjohn. At the time of this writing, these patients had not been published in the literature. All of the patients had to have documented evidence of serious gram-positive infections in normally sterile sites and should have been unable to tolerate available antimicrobial therapy or be unresponsive to available drugs. Clinical characteristics, laboratory values, and pharmacokinetic and pharmacodynamic parameters were obtained. Patients were followed both short-term and long-term after completion of therapy. Nineteen patients were enrolled: 13 females and 6 males. The average age was 63 years. The average length of therapy with linezolid was 22 days. Methicillin-resistant Staphylococcus aureus (MRSA) was treated in eight patients, methicillin-resistant Staphylococcus epidermidis (MRSE) in two patients, vancomycin-resistant Enterococcus faecium (VREF) in eight patients, and coagulase-negative Staphylococcus in two patients. Co-infecting organisms include Enterococcus species colonization in six patients, Pseudomonas species in one patient, Serratia marcenens in one patient, and Candida albicans in one patient. Sterile sites that were infected included bone and joint (wounds and septic joints) in six patients, gastrointestinal system (hepatobiliary, liver abscess, Crohn's) in five patients, genitourinary (kidney and urine) in two patients, blood in five patients, respiratory in one patient, and aortic valve in 1 patient. Linezolid was given at 600 mg IV every 12 hours with a mean length of therapy of 22 days. Surgical drainage was used in combination with linezolid in 11 of the patients. Seventy nine percent of these patients achieved clinical and microbiologic cure, and none of the deaths reported in this series were related to the drug. Adverse events included skin rash in one patient, mild bone marrow suppression in two patients, and mild elevation in liver function tests in two patients. No life-threatening adverse events were noted. It appears that linezolid, along with surgical intervention (when necessary), appears to be an effective treatment option for resistant gram-positive infections. Long-term studies evaluating the possible resistance rates are necessary.

Antony, S. J.; Diaz-Vasquez, E.; Stratton, C.

2001-01-01

129

Proinflammatory activity of cell-wall constituents from gram-positive bacteria.  

PubMed

Innate immunity reacts to conserved bacterial molecules. The outermost lipopolysaccharide (LPS) of Gram-negative organisms is highly inflammatory. It activates responsive cells via specific CD14 and toll-like receptor-4 (TLR4) surface receptor and co-receptors. Gram-positive bacteria do not contain LPS, but carry surface teichoic acids, lipoteichoic acids and peptidoglycan instead. Among these, the thick peptidoglycan is the most conserved. It also triggers cytokine release via CD14, but uses the TLR2 co-receptor instead of TLR4 used by LPS. Moreover, whole peptidoglycan is 1000-fold less active than LPS in a weight-to-weight ratio. This suggests either that it is not important for inflammation, or that only part of it is reactive while the rest acts as ballast. Biochemical dissection of Staphylococcus aureus and Streptococcus pneumoniae cell walls indicates that the second assumption is correct. Long, soluble peptidoglycan chains (approximately 125 kDa) are poorly active. Hydrolysing these chains to their minimal unit (2 sugars and a stem peptide) completely abrogates inflammation. Enzymatic dissection of the pneumococcal wall generated a mixture of highly active fragments, constituted of trimeric stem peptides, and poorly active fragments, constituted of simple monomers and dimers or highly polymerized structures. Hence, the optimal constraint for activation might be 3 cross-linked stem peptides. The importance of structural constraint was demonstrated in additional studies. For example, replacing the first L-alanine in the stem peptide with a D-alanine totally abrogated inflammation in experimental meningitis. Likewise, modifying the D-alanine decorations of lipoteichoic acids with L-alanine, or deacylating them from their diacylglycerol lipid anchor also decreased the inflammatory response. Thus, although considered as a broad-spectrum pattern-recognizing system, innate immunity can detect very subtle differences in Gram-positive walls. This high specificity underlines the importance of using well-characterized microbial material in investigating the system. PMID:14620147

Moreillon, P; Majcherczyk, P A

2003-01-01

130

Antimicrobial activity of metal oxide nanoparticles against Gram-positive and Gram-negative bacteria: a comparative study  

PubMed Central

Background Nanomaterials have unique properties compared to their bulk counterparts. For this reason, nanotechnology has attracted a great deal of attention from the scientific community. Metal oxide nanomaterials like ZnO and CuO have been used industrially for several purposes, including cosmetics, paints, plastics, and textiles. A common feature that these nanoparticles exhibit is their antimicrobial behavior against pathogenic bacteria. In this report, we demonstrate the antimicrobial activity of ZnO, CuO, and Fe2O3 nanoparticles against Gram-positive and Gram-negative bacteria. Methods and results Nanosized particles of three metal oxides (ZnO, CuO, and Fe2O3) were synthesized by a sol–gel combustion route and characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and transmission electron microscopy techniques. X-ray diffraction results confirmed the single-phase formation of all three nanomaterials. The particle sizes were observed to be 18, 22, and 28 nm for ZnO, CuO, and Fe2O3, respectively. We used these nanomaterials to evaluate their antibacterial activity against both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria. Conclusion Among the three metal oxide nanomaterials, ZnO showed greatest antimicrobial activity against both Gram-positive and Gram-negative bacteria used in this study. It was observed that ZnO nanoparticles have excellent bactericidal potential, while Fe2O3 nanoparticles exhibited the least bactericidal activity. The order of antibacterial activity was demonstrated to be the following: ZnO > CuO > Fe2O3.

Azam, Ameer; Ahmed, Arham S; Oves, Mohammad; Khan, Mohammad S; Habib, Sami S; Memic, Adnan

2012-01-01

131

Bacillus hackensackii” sp. nov., a novel carbon dioxide sensitive bacterium isolated from blood culture  

Microsoft Academic Search

An endospore-forming, gram-positive bacillus was isolated from a patient’s blood culture. This bacillus did not grow in the presence of 5% carbon dioxide although it grew well in ambient air at 37°C. Although the organism thus is an aerobic bacterium, its sensitivity to increased carbon dioxide concentration places it in a distinct category of gaseous atmospheric requirement: capnophobic. Based on

Tao Hong; Nueda Heibler; Y. i-Wei Tang

2003-01-01

132

Caenorhabditis elegans immune conditioning with the probiotic bacterium Lactobacillus acidophilus strain NCFM enhances gram-positive immune responses.  

PubMed

Although the immune response of Caenorhabditis elegans to microbial infections is well established, very little is known about the effects of health-promoting probiotic bacteria on evolutionarily conserved C. elegans host responses. We found that the probiotic Gram-positive bacterium Lactobacillus acidophilus NCFM is not harmful to C. elegans and that L. acidophilus NCFM is unable to colonize the C. elegans intestine. Conditioning with L. acidophilus NCFM significantly decreased the burden of a subsequent Enterococcus faecalis infection in the nematode intestine and prolonged the survival of nematodes exposed to pathogenic strains of E. faecalis and Staphylococcus aureus, including multidrug-resistant (MDR) isolates. Preexposure of nematodes to Bacillus subtilis did not provide any beneficial effects. Importantly, L. acidophilus NCFM activates key immune signaling pathways involved in C. elegans defenses against Gram-positive bacteria, including the p38 mitogen-activated protein kinase pathway (via TIR-1 and PMK-1) and the ?-catenin signaling pathway (via BAR-1). Interestingly, conditioning with L. acidophilus NCFM had a minimal effect on Gram-negative infection with Pseudomonas aeruginosa or Salmonella enterica serovar Typhimurium and had no or a negative effect on defense genes associated with Gram-negative pathogens or general stress. In conclusion, we describe a new system for the study of probiotic immune agents and our findings demonstrate that probiotic conditioning with L. acidophilus NCFM modulates specific C. elegans immunity traits. PMID:22585961

Kim, Younghoon; Mylonakis, Eleftherios

2012-05-14

133

Caenorhabditis elegans Immune Conditioning with the Probiotic Bacterium Lactobacillus acidophilus Strain NCFM Enhances Gram-Positive Immune Responses  

PubMed Central

Although the immune response of Caenorhabditis elegans to microbial infections is well established, very little is known about the effects of health-promoting probiotic bacteria on evolutionarily conserved C. elegans host responses. We found that the probiotic Gram-positive bacterium Lactobacillus acidophilus NCFM is not harmful to C. elegans and that L. acidophilus NCFM is unable to colonize the C. elegans intestine. Conditioning with L. acidophilus NCFM significantly decreased the burden of a subsequent Enterococcus faecalis infection in the nematode intestine and prolonged the survival of nematodes exposed to pathogenic strains of E. faecalis and Staphylococcus aureus, including multidrug-resistant (MDR) isolates. Preexposure of nematodes to Bacillus subtilis did not provide any beneficial effects. Importantly, L. acidophilus NCFM activates key immune signaling pathways involved in C. elegans defenses against Gram-positive bacteria, including the p38 mitogen-activated protein kinase pathway (via TIR-1 and PMK-1) and the ?-catenin signaling pathway (via BAR-1). Interestingly, conditioning with L. acidophilus NCFM had a minimal effect on Gram-negative infection with Pseudomonas aeruginosa or Salmonella enterica serovar Typhimurium and had no or a negative effect on defense genes associated with Gram-negative pathogens or general stress. In conclusion, we describe a new system for the study of probiotic immune agents and our findings demonstrate that probiotic conditioning with L. acidophilus NCFM modulates specific C. elegans immunity traits.

2012-01-01

134

In Situ Characterization of Differences in the Viscoelastic Response of Individual Gram-Negative and Gram-Positive Bacterial Cells?  

PubMed Central

We used a novel atomic force microscopy (AFM)-based technique to compare the local viscoelastic properties of individual gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacterial cells. We found that the viscoelastic properties of the bacterial cells are well described by a three-component mechanical model that combines an instantaneous elastic response and a delayed elastic response. These experiments have allowed us to investigate the relationship between the viscoelastic properties and the structure and composition of the cell envelope. In addition, this is the first report in which the mechanical role of Lpp, the major peptidoglycan-associated lipoprotein and one of the most abundant outer membrane proteins in E. coli cells, has been quantified. We expect that our findings will be helpful in increasing the understanding of the structure-property relationships of bacterial cell envelopes.

Vadillo-Rodriguez, Virginia; Schooling, Sarah R.; Dutcher, John R.

2009-01-01

135

Isolating "Unknown" Bacteria in the Introductory Microbiology Laboratory: A New Selective Medium for Gram-Positives.  

ERIC Educational Resources Information Center

|Describes the development, preparation, and use of a medium that can select against a wide variety of Gram-negative bacteria while still allowing growth and differentiation of a wide range of Gram-positives. (WRM)|

McKillip, John L.; Drake, MaryAnne

1999-01-01

136

Antibiotic-Resistant Gram-Positive Cocci: Implications for Surgical Practice  

Microsoft Academic Search

. Gram-positive infections are causing more serious infections than ever before in surgical patients, who are increasingly\\u000a aged, ill, and debilitated. Invasive procedures disrupt natural barriers to bacterial invasion, and indwelling catheters may\\u000a act as conduits for infection. The use of broad-spectrum antibiotics selects for the emergence of resistant pathogens. Potential\\u000a sites of nosocomial gram-positive infections include the urinary tract,

Philip S. Barie

1998-01-01

137

A consensus statement on empiric therapy for suspected gram-positive infections in surgical patients  

Microsoft Academic Search

Background: Multidrug resistance among gram-positive pathogens in tertiary and other care centers is common. A systematic decision pathway to help select empiric antibiotic therapy for suspected gram-positive postsurgical infections is presented. Data sources: A Medline search with regard to empiric antibiotic therapy was performed and assessed by the 15-member expert panel. Two separate panel meetings were convened and followed by

Joseph S. Solomkin; H. Stephen Bjornson; Miguel Cainzos; E. Patchen Dellinger; Lorenzo Dominioni; Robert Eidus; Eugen Faist; David Leaper; James T. Lee; Pamela A. Lipsett; Lena Napolitano; Carl L. Nelson; Robert G. Sawyer; John Weigelt; Samuel Eric Wilson

2004-01-01

138

A Comparative Genome Analysis Identifies Distinct Sorting Pathways in Gram-Positive Bacteria  

Microsoft Academic Search

Surface proteins in gram-positive bacteria are frequently required for virulence, and many are attached to the cell wall by sortase enzymes. Bacteria frequently encode more than one sortase enzyme and an even larger number of potential sortase substrates that possess an LPXTG-type cell wall sorting signal. In order to elucidate the sorting pathways present in gram-positive bacteria, we performed a

David Comfort; Robert T. Clubb

2004-01-01

139

An Export-Specific Reporter Designed for Gram-Positive Bacteria: Application to Lactococcus lactis  

Microsoft Academic Search

The identification of exported proteins by fusion studies, while well developed for gram-negative bacteria, is limited for gram-positive bacteria, in part due to drawbacks of available export reporters. In this work, we demonstrate the export specificity and use of the Staphylococcus aureus secreted nuclease (Nuc) as a reporter for gram-positive bacteria. Nuc devoid of its export signal (called DSPNuc) was

ISABELLE POQUET; S. DUSKO EHRLICH; ALEXANDRA GRUSS

1998-01-01

140

Interaction of Cationic Peptides with Lipoteichoic Acid and Gram-Positive Bacteria  

Microsoft Academic Search

Compounds with antiendotoxin properties have been extensively studied for their potential as therapeutic agents for sepsis attributable to gram-negative bacteria. However, with the increasing incidence of gram- positive sepsis, there is interest in identifying compounds with a broad spectrum of action against both gram-positive and gram-negative bacteria. A series of synthetic a-helical cationic peptides related to bee melittin and silk

MONISHA G. SCOTT; MICHAEL R. GOLD; ROBERT E. W. HANCOCK

1999-01-01

141

Distribution of mef(A) in Gram-Positive Bacteria from Healthy Portuguese Children  

Microsoft Academic Search

We screened 615 gram-positive isolates from 150 healthy children for the presence of the erm(A), erm(B), erm(C), erm(F), and mef(A) genes. The mef(A) genes were found in 20 (9%) of the macrolide-resistant isolates, including Enterococcus spp., Staphylococcus spp., and Streptococcus spp. Sixteen of the 19 gram-positive isolates tested carried the other seven open reading frames (ORFs) described in Tn1207.1, a

Vicki A. Luna; Marc Heiken; Kathleen Judge; Catherine Ulep; Nicole Van Kirk; Henrique Luis; Mario Bernardo; Jose Leitao; Marilyn C. Roberts

2002-01-01

142

Protein sorting to the cell wall envelope of Gram-positive bacteria  

Microsoft Academic Search

The covalent anchoring of surface proteins to the cell wall envelope of Gram-positive bacteria occurs by a universal mechanism requiring sortases, extracellular transpeptidases that are positioned in the plasma membrane. Surface protein precursors are first initiated into the secretory pathway of Gram-positive bacteria via N-terminal signal peptides. C-terminal sorting signals of surface proteins, bearing an LPXTG motif or other recognition

Hung Ton-That; Luciano A. Marraffini; Olaf Schneewind

2004-01-01

143

Production of acylated homoserine lactone by gram-positive bacteria isolated from marine water.  

PubMed

Acylated homoserine lactone (AHL)-based quorum sensing (QS) has been reported to be present only in Gram-negative microorganisms. Isolation of a novel Gram-positive microorganism from sea water, capable of producing AHL, is reported here. The isolate (GenBank: JF915892, designated as MPO) belonging to the Exiguobacterium genera is capable of inducing the AHL bioreporters, namely Chromobacterium violaceum CV026, Agrobacterium tumefaceins A136, and E. coli JM 109(psb1075). This inducer is characterized as C3-oxo-octanoyl homoserine lactone (OOHL), and its production reaches a maximum of 15.6 ?g L(-1), during the stationary growth phase of the organism. MPO extract when exogenously added inhibits the formation of biofilm for the same organism and lowers the extracellular polymeric substances, indicating an AHL-associated phenotypic trait. The isolated sequence of a probable LuxR homolog from MPO (designated as ExgR) shows similar functional domains and contains conserved residues in LuxR from other known bacterial QS LuxR regulators. Also present immediately downstream to ExgR was found a sequence showing homology to known LuxI synthase of Pseudomonas putida. qPCR analysis suggests an increment in exgR mRNA on addition of AHL, further proving the role of ExgR as a QS regulator. PMID:23489290

Biswa, Pramal; Doble, Mukesh

2013-04-02

144

Two Cases of Endogenous Endophthalmitis Caused by Gram-Positive Bacteria with Good Visual Outcome  

PubMed Central

Background Endogenous endophthalmitis is a rare disease and its visual prognosis is poor. Case Reports We present two patients, a 60-year-old man and a 53-year-old man, who developed endogenous endophthalmitis caused by Gram-positive organisms but recovered good vision after antibiotics and vitrectomy. Results The first patient complained of ocular pain and visual decrease in his right eye. Ophthalmoscopy showed inflammation in the anterior chamber and vitreous opacities. Antibiotic was administrated systemically, and blood culture detected Streptococcus anginosus. He underwent successful heart surgery for endocarditis and total dental extraction for severe gingivitis. Vitrectomy was performed 36 days after the onset and vision improved from 0.02 to 0.7. The second patient was referred for acute visual decrease in his left eye. Severe iritis and vitreous opacities were observed, and systemic examination showed acute pyelitis and prostatic abscesses. Blood cultures detected Staphylococcus sp., and systemic antibiotics were given. Vitrectomy was performed 12 days after the onset, and vision improved from 0.06 to 1.2. Conclusions We conclude that the rapid treatment with systemic antibiotics for the organisms at the primary site, and the vitrectomy, even though delayed, can lead to a good recovery of vision.

Itoh, Machiko; Ikewaki, Junko; Kimoto, Kenichi; Itoh, Yuji; Shinoda, Kei; Nakatsuka, Kazuo

2010-01-01

145

Two Cases of Endogenous Endophthalmitis Caused by Gram-Positive Bacteria with Good Visual Outcome.  

PubMed

BACKGROUND: Endogenous endophthalmitis is a rare disease and its visual prognosis is poor. CASE REPORTS: We present two patients, a 60-year-old man and a 53-year-old man, who developed endogenous endophthalmitis caused by Gram-positive organisms but recovered good vision after antibiotics and vitrectomy. RESULTS: The first patient complained of ocular pain and visual decrease in his right eye. Ophthalmoscopy showed inflammation in the anterior chamber and vitreous opacities. Antibiotic was administrated systemically, and blood culture detected Streptococcus anginosus. He underwent successful heart surgery for endocarditis and total dental extraction for severe gingivitis. Vitrectomy was performed 36 days after the onset and vision improved from 0.02 to 0.7. The second patient was referred for acute visual decrease in his left eye. Severe iritis and vitreous opacities were observed, and systemic examination showed acute pyelitis and prostatic abscesses. Blood cultures detected Staphylococcus sp., and systemic antibiotics were given. Vitrectomy was performed 12 days after the onset, and vision improved from 0.06 to 1.2. CONCLUSIONS: We conclude that the rapid treatment with systemic antibiotics for the organisms at the primary site, and the vitrectomy, even though delayed, can lead to a good recovery of vision. PMID:21103197

Itoh, Machiko; Ikewaki, Junko; Kimoto, Kenichi; Itoh, Yuji; Shinoda, Kei; Nakatsuka, Kazuo

2010-09-21

146

Current and prospective treatments for multidrug-resistant gram-positive infections.  

PubMed

Introduction: Staphylococcus aureus and Enterococcus spp. are two of the most common organisms causing nosocomial infections today; and are consistently associated with high mortality rates (approximately 20 and 44%, respectively). Resistance among these pathogens to first line agents such as methicillin and vancomycin continues to rise while isolates with reduced susceptibility to newer agents including linezolid and daptomycin continue to emerge, representing a serious concern for clinicians. Areas covered: Mechanisms of action and resistance as well as in vitro and clinical experience in the treatment of resistant staphylococci and enterococci with currently available agents are discussed. Additionally, novel combination regimens showing enhanced efficacy and available data pertaining to prospective therapies including solithromycin, tedizolid, dalbavancin and oritavancin will be covered. Expert opinion: With an increase in organisms displaying reduced susceptibility to vancomycin and the associated treatment failures, the significance of alternative therapies such as daptomycin, linezolid, ceftaroline, and prospective anti-gram-positive agents is on the rise. As our understanding of antimicrobial pharmacokinetic-pharmacodynamics principles continues to evolve, the selection of highly effective agents and optimization of dosages may lead to improved patient outcomes and delay the development of resistance. PMID:23876168

Rybak, Jeffrey M; Barber, Katie E; Rybak, Michael J

2013-07-22

147

Is leprosy bacillus a chemo-autotrophic nocardioform organism?  

PubMed

Numerous attempts at in vitro cultivation of the leprosy bacillus have all proved to be unsuccessful. Recently, we have repeatedly isolated chemo-autotrophic nocardioform (CAN) organisms in pure culture from multibacillary cases of leprosy. We find that these resemble the leprosy bacillus in many respects and suggest that the leprosy bacillus may be closer to the genus Nocardia than to Mycobacterium, and that it may be a chemo-autotroph, requiring only simple sources of carbon and nitrogen for its growth. This is in contrast to most other human pathogens, which are heterotrophs requiring complex sources of carbon and nitrogen for their growth. This could offer a possible explanation for the repeated failure at in vitro cultivation of the leprosy bacillus. PMID:2262721

Pal, D; Chakrabarty, A N; Dastidar, S G

148

Functional modulation of enterocytes by gram-positive and gram-negative microorganisms.  

PubMed

Clinical studies have suggested that so-called probiotic bacteria may be effective as therapy in inflammatory bowel disease. However, the molecular mechanisms of their interaction with the intestinal surface remain undefined. The influence of whole probiotic bacteria [Escherichia coli Nissle 1917 (EcN); probiotic mixture VSL#3 (PM)], bacterial cell lysates, and conditioned media on transepithelial resistance (TER), IL-8 secretion, mucin gene expression, and tight junction proteins were determined in T84 and HT-29 intestinal epithelial cells (IEC). In addition, effects on pathogen (Salmonella dublin)-induced alterations were analyzed. EcN as well as debris and cell extracts induced IL-8 secretion from IEC, whereas no such effect was observed following incubation with the PM. The PM and soluble protein(s) released from the PM increased TER, prevented pathogen-induced decrease in TER, and were shown to stabilize tight junctions. The PM induced expression of mucins in IEC, and these organisms as well as EcN diminished S. dublin-induced cell death. Inhibition of MAPKs with PD-98059 or SB-203580 significantly decreased alterations in IL-8 synthesis and mucin expression and affected the regulation of TER. Probiotics and protein(s) released by these organisms may functionally modulate the intestinal epithelium of the host by different mechanisms, including the competition of whole organisms for contact with the epithelial surface as well as stabilization of the cytoskeleton and barrier function and the induction of mucin expression. Gram-negative and gram-positive organisms differ in the mechanisms activated, and a combination of organisms might be more effective than the application of a single strain. PMID:15010363

Otte, Jan-Michel; Podolsky, Daniel K

2004-04-01

149

Development of a Flow Chart for Identification of Gram-Positive Anaerobic Cocci in the Clinical Laboratory?  

PubMed Central

Gram-positive anaerobic cocci (GPAC) are a heterogeneous group of organisms that are isolated from clinical specimens more often than any group of anaerobic bacteria except Bacteroides species, yet many strains are still difficult or impossible to identify in the diagnostic laboratory. In this study, a total of 124 strains, including 13 reference strains of GPAC species and 111 isolates that had been recovered from clinical specimens previously and identified by 16S rRNA gene sequencing, were subjected to biochemical characterization. Based on the results, a short biochemical scheme that involves the minimum essential biochemical tests for accurate identification of clinically important GPAC was developed.

Song, Yuli; Liu, Chengxu; Finegold, Sydney M.

2007-01-01

150

Metabolic basis for the differential susceptibility of Gram-positive pathogens to fatty acid synthesis inhibitors  

PubMed Central

The rationale for the pursuit of bacterial type 2 fatty acid synthesis (FASII) as a target for antibacterial drug discovery in Gram-positive organisms is being debated vigorously based on their ability to incorporate extracellular fatty acids. The regulation of FASII by extracellular fatty acids was examined in Staphylococcus aureus and Streptococcus pneumoniae, representing two important groups of pathogens. Both bacteria use the same enzymatic tool kit for the conversion of extracellular fatty acids to acyl-acyl carrier protein, elongation, and incorporation into phospholipids. Exogenous fatty acids completely replace the endogenous fatty acids in S. pneumoniae but support only 50% of phospholipid synthesis in S. aureus. Fatty acids overcame FASII inhibition in S. pneumoniae but not in S. aureus. Extracellular fatty acids strongly suppress malonyl-CoA levels in S. pneumoniae but not in S. aureus, showing a feedback regulatory system in S. pneumoniae that is absent in S. aureus. Fatty acids overcame either a biochemical or a genetic block at acetyl-CoA carboxylase (ACC) in S. aureus, confirming that regulation at the ACC step is the key difference between these two species. Bacteria that possess a stringent biochemical feedback inhibition of ACC and malonyl-CoA formation triggered by environmental fatty acids are able to circumvent FASII inhibition. However, if exogenous fatty acids do not suppress malonyl-CoA formation, FASII inhibitors remain effective in the presence of fatty acid supplements.

Parsons, Joshua B.; Frank, Matthew W.; Subramanian, Chitra; Saenkham, Panatda; Rock, Charles O.

2011-01-01

151

Complete genome sequence of the industrial bacterium Bacillus licheniformis and comparisons with closely related Bacillus species  

Microsoft Academic Search

Background  \\u000a Bacillus licheniformis is a Gram-positive, spore-forming soil bacterium that is used in the biotechnology industry to manufacture enzymes, antibiotics,\\u000a biochemicals and consumer products. This species is closely related to the well studied model organism Bacillus subtilis, and produces an assortment of extracellular enzymes that may contribute to nutrient cycling in nature.\\u000a \\u000a \\u000a \\u000a \\u000a Results  We determined the complete nucleotide sequence of the

Michael W Rey; Preethi Ramaiya; Beth A Nelson; Shari D Brody-Karpin; Elizabeth J Zaretsky; Maria Tang; Alfredo Lopez de Leon; Henry Xiang; Veronica Gusti; Ib Groth Clausen; Peter B Olsen; Michael D Rasmussen; Jens T Andersen; Per L Jørgensen; Thomas S Larsen; Alexei Sorokin; Alexander Bolotin; Alla Lapidus; Nathalie Galleron; S Dusko Ehrlich; Randy M Berka

2004-01-01

152

Vancomycin-resistant gram-positive bacteria isolated from human sources.  

PubMed Central

Recent reports of infections with vancomycin-resistant gram-positive bacteria prompted us to study vancomycin-resistant isolates from human sources to characterize the types of bacteria displaying this phenotype. Thirty-six vancomycin-resistant gram-positive isolates, 14 from clinical specimens and 22 from stool samples, were identified. These isolates were tentatively identified as Lactobacillus spp. (25 strains), Leuconostoc spp. (6 strains), and Pediococcus spp. (3 strains) on the basis of morphology and physiological tests. Two isolates of indeterminate morphology could not be unambiguously assigned to a genus. Four isolates of vancomycin-resistant lactobacilli from normally sterile body sites were considered to be clinically significant. Vancomycin-resistant gram-positive bacteria may represent an emerging class of nosocomial pathogens. Better methods for distinguishing the various genera in the clinical microbiology laboratory are needed.

Ruoff, K L; Kuritzkes, D R; Wolfson, J S; Ferraro, M J

1988-01-01

153

Rose Bengal-decorated silica nanoparticles as photosensitizers for inactivation of gram-positive bacteria  

NASA Astrophysics Data System (ADS)

A new type of photosensitizer, made from Rose Bengal (RB)-decorated silica (SiO2-NH2-RB) nanoparticles, was developed to inactivate gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA), with high efficiency through photodynamic action. The nanoparticles were characterized microscopically and spectroscopically to confirm their structures. The characterization of singlet oxygen generated by RB, both free and immobilized on a nanoparticle surface, was performed in the presence of anthracene-9,10-dipropionic acid. The capability of SiO2-NH2-RB nanoparticles to inactivate bacteria was tested in vitro on both gram-positive and gram-negative bacteria. The results showed that RB-decorated silica nanoparticles can inactivate MRSA and Staphylococcus epidermidis (both gram-positive) very effectively (up to eight-orders-of-magnitude reduction). Photosensitizers of such design should have good potential as antibacterial agents through a photodynamic mechanism.

Guo, Yanyan; Rogelj, Snezna; Zhang, Peng

2010-02-01

154

Oritavancin: a new promising agent in the treatment of infections due to Gram-positive pathogens.  

PubMed

Nosocomial and community-acquired infections caused by Gram-positive pathogens continue to be a challenge, mainly due to the increasing rates of resistance among Staphylococcus spp. and Enterococcus spp. Oritavancin, a new parenteral semisynthetic glycopeptide, possessing rapid bactericidal action and an antimicrobial spectrum containing all Gram-positive pathogens (streptococci, staphylococci, enterococci--vancomycin-resistant enterococci included--and Clostridia spp.) irrespective of their resistance status to the precursor molecule of vancomycin, is expected to file a new drug application by the first trimester of 2008. Once-daily dosing, good penetration into macrophages, in vitro activity against bacteria embedded in biofilms and low adverse reaction potential are further considered as oritavancin's advantages over existing drugs. While waiting for the results of supplementary Phase III studies to be announced, preliminary reports suggest the new drug will be a welcome addition to the existing antimicrobial armamentarium against Gram-positive cocci. PMID:18230056

Poulakou, Garyphallia; Giamarellou, Helen

2008-02-01

155

Genomics of Bacillus Species  

NASA Astrophysics Data System (ADS)

Members of the genus Bacillus are rod-shaped spore-forming bacteria belonging to the Firmicutes, the low G+C gram-positive bacteria. The Bacillus genus was first described and classified by Ferdinand Cohn in Cohn (1872), and Bacillus subtilis was defined as the type species (Soule, 1932). Several Bacilli may be linked to opportunistic infections. However, pathogenicity among Bacillus spp. is mainly a feature of bacteria belonging to the Bacillus cereus group, including B. cereus, Bacillus anthracis, and Bacillus thuringiensis. Here we review the genomics of B. cereus group bacteria in relation to their roles as etiological agents of two food poisoning syndromes (emetic and diarrhoeal).

Økstad, Ole Andreas; Kolstø, Anne-Brit

156

Contemporary tetracycline susceptibility testing: doxycycline MIC methods and interpretive criteria (CLSI and EUCAST) performance when testing Gram-positive pathogens.  

PubMed

International susceptibility testing breakpoint organizations and regulatory agencies have markedly differing interpretive criteria for the tetracycline class. Here we examined the magnitude of these differences for doxycycline and tetracycline hydrochloride (HCL) when tested against a collection of 13,176 Gram-positive cocci from a worldwide surveillance network (SENTRY Antimicrobial Surveillance Program, 2010). Clinical and Laboratory Standards Institute (CLSI) breakpoints are routinely higher, usually 4-fold, compared to those of the European Committee on Antimicrobial Susceptibility Testing (EUCAST); however, CLSI recently (2013) modified Streptococcus pneumoniae breakpoints (? 2 ?g/mL in 2012) to ? 0.25 and ? 1 ?g/mL for doxycycline and tetracycline HCL, respectively. We report that these changes are a promising step toward international breakpoint harmonization, but lack a comprehensive approach needed for testing tetracyclines against all Gram-positive cocci. Generally, EUCAST breakpoint criteria showed i) lower spectrums (reduced susceptibility rates) for the tetracyclines, but highest for doxycycline versus all species examined; ii) greater test accuracy (lower predictive categorical errors), especially for tetracycline to predict doxycycline susceptibility (99.91%); and iii) zone diameter correlate breakpoints which are generally available online. Molecular tests for tet resistance genes demonstrate that tet (K) and tet (M) containing strains can occur in the susceptible population of MIC results by both CLSI and EUCAST breakpoint criteria. In summary, doxycycline continues to show greater comparative potency versus tetracycline HCL against all monitored Gram-positive species and the international harmonization of tetracycline breakpoints should be a priority, as the most recent CLSI update only addressed 1 streptococcal species and 2 tetracycline agents. PMID:23490012

Jones, Ronald N; Stilwell, Matthew G; Wilson, Michael L; Mendes, Rodrigo E

2013-03-13

157

Leaving home ain't easy: protein export systems in Gram-positive bacteria.  

PubMed

Transport of proteins into or across biological membranes is catalyzed by membrane-bound transport machineries. In Gram-positive bacteria, the vast majority of proteins are exported out of the cytosol by the conserved general secretion (Sec) system or, alternatively, by the twin-arginine translocation (Tat) system, that closely resemble their well-studied counterparts in Gram-negative bacteria. Besides these common major export routes, additional unique protein export systems (such as accessory Sec2 systems and/or type VII/WXG100 secretion systems) exist in some Gram-positive bacteria that are specifically involved in the secretion of limited subsets of proteins. PMID:23541477

Freudl, Roland

2013-03-26

158

Pathogenomic Sequence Analysis of Bacillus cereus and Bacillus thuringiensis Isolates Closely Related to Bacillus anthracis  

Microsoft Academic Search

Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis are closely related gram-positive, spore-forming bacteria of the B. cereus sensu lato group. While independently derived strains of B. anthracis reveal conspic- uous sequence homogeneity, environmental isolates of B. cereus and B. thuringiensis exhibit extensive genetic diversity. Here we report the sequencing and comparative analysis of the genomes of two members of the

Cliff S. Han; Gary Xie; Jean F. Challacombe; Michael R. Altherr; Smriti S. Bhotika; N. Brown; Connie S. Campbell; M. L. Campbell; Olga Chertkov; Mira Dimitrijevic; N. A. Doggett; J. J. Fawcett; Lynne A. Goodwin; Penny Hitchcock; Paul J. Jackson; Avinash Ramesh Kewalramani; Jon Longmire; Kim McMurry; Linda J. Meincke; M. Misra; B. L. Moseman; Richard T. Okinaka; B. Parson-Quintana; Donna L. Robinson; P. Richardson; E. Rubin; E. Saunders; Nina Thayer; Linda S. Thompson; Patti L. Wills; L. O. Ticknor; T. S. Brettin; P. Gilna

2006-01-01

159

Studies on biodegradation of organic flotation collectors using Bacillus polymyxa  

Microsoft Academic Search

Biodegradation of organic flotation collectors, namely sodium isopropylxanthate, dodecylammonium acetate and sodium oleate in solution, was studied using Bacillus polymyxa. The biodegradation has been assessed under different conditions, namely during growth, in the presence of the cells, metabolite or an active culture. Xanthate biodegradation was found to be better in the presence of an active culture or metabolite, while the

Evvie Chockalingam; S Subramanian; K. A Natarajan

2003-01-01

160

Construction and evaluation of multisite recombinatorial (Gateway) cloning vectors for Gram-positive bacteria  

PubMed Central

Background The Gateway recombinatorial cloning system allows easy and rapid joining of DNA fragments. Here we report the construction and evaluation of three different Gram-positive vectors that can be used with the Multisite Gateway cloning system to rapidly produce new gene arrangements in plasmid constructs for use in a variety of Gram-positive bacteria. Results Comparison of patterns of reporter gene expression with conventionally constructed clones show that the presence of residual recombination (att) sites does not have an effect on patterns of gene expression, although overall levels of gene expression may vary. Rapid construction of these new vectors allowed vector/gene combinations to be optimized following evaluation of plasmid constructs in different bacterial cells and demonstrates the benefits of plasmid construction using Gateway cloning. Conclusion The residual att sites present after Gateway cloning did not affect patterns of promoter induction in Gram-positive bacteria and there was no evidence of differences in mRNA stability of transcripts. However overall levels of gene expression may be reduced, possibly due to some post-transcriptional event. The new vectors described here allow faster, more efficient cloning in range of Gram-positive bacteria.

Perehinec, Tania M; Qazi, Saara NA; Gaddipati, Sanyasi R; Salisbury, Vyvyan; Rees, Catherine ED; Hill, Philip J

2007-01-01

161

Superantigens of Gram-positive bacteria: structure—function analyses and their implications for biological activity  

Microsoft Academic Search

Just as we thought that we know everything about superantigens, new molecular and structural studies indicate that we have only just begun to unravel the secrets of these fascinating molecules. Recent structure—function analysis of superantigens from Gram-positive bacteria, with emphasis on their interaction with major histocompatibility complex molecules, could help us decipher the role of superantigens in disease, identify host

Malak Kotb

1998-01-01

162

Mode of action of modified and unmodified bacteriocins from Gram-positive bacteria  

Microsoft Academic Search

The antibiotic activity of bacteriocins from Gram-positive bacteria, whether they are modified (class I bacteriocins, lantibiotics) or unmodified (class II), is based on interaction with the bacterial membrane. However, recent work has demonstrated that for many bacteriocins, generalised membrane disruption models as elaborated for amphiphilic peptides (e.g. tyriodal pore or carpet model) cannot adequately describe the bactericidal action. Rather, specific

Yann Héchard; Hans-Georg Sahl

2002-01-01

163

Novel Antibiotics Targeting Respiratory ATP Synthesis in Gram-Positive Pathogenic Bacteria  

PubMed Central

Emergence of drug-resistant bacteria represents a high, unmet medical need, and discovery of new antibacterials acting on new bacterial targets is strongly needed. ATP synthase has been validated as an antibacterial target in Mycobacterium tuberculosis, where its activity can be specifically blocked by the diarylquinoline TMC207. However, potency of TMC207 is restricted to mycobacteria with little or no effect on the growth of other Gram-positive or Gram-negative bacteria. Here, we identify diarylquinolines with activity against key Gram-positive pathogens, significantly extending the antibacterial spectrum of the diarylquinoline class of drugs. These compounds inhibited growth of Staphylococcus aureus in planktonic state as well as in metabolically resting bacteria grown in a biofilm culture. Furthermore, time-kill experiments showed that the selected hits are rapidly bactericidal. Drug-resistant mutations were mapped to the ATP synthase enzyme, and biochemical analysis as well as drug-target interaction studies reveal ATP synthase as a target for these compounds. Moreover, knockdown of the ATP synthase expression strongly suppressed growth of S. aureus, revealing a crucial role of this target in bacterial growth and metabolism. Our data represent a proof of principle for using the diarylquinoline class of antibacterials in key Gram-positive pathogens. Our results suggest that broadening the antibacterial spectrum for this chemical class is possible without drifting off from the target. Development of the diarylquinolines class may represent a promising strategy for combating Gram-positive pathogens.

Balemans, Wendy; Vranckx, Luc; Lounis, Nacer; Pop, Ovidiu; Guillemont, Jerome; Vergauwen, Karen; Mol, Selena; Gilissen, Ron; Motte, Magali; Lancois, David; De Bolle, Miguel; Bonroy, Kristien; Lill, Holger; Andries, Koen

2012-01-01

164

Peritonitis due to uncommon gram-positive pathogens in children undergoing peritoneal dialysis  

PubMed Central

Peritonitis is still the main complication of peritoneal dialysis (PD) in children. Staphylococcus, especially Staphylococcus epidermidis and Staphylococcus aureus, are the predominant species isolated, followed by Streptococcus spp. and by far by gram-negative bacteria and fungi. We describe three cases of PD-related peritonitis in pediatric patients due to uncommon gram-positive pathogens, which were treated with intraperitoneal antibiotic agents.

Dotis, J; Printza, N; Papachristou, F

2012-01-01

165

Small molecule inhibitor of lipoteichoic acid synthesis is an antibiotic for Gram-positive bacteria  

PubMed Central

The current epidemic of infections caused by antibiotic-resistant Gram-positive bacteria requires the discovery of new drug targets and the development of new therapeutics. Lipoteichoic acid (LTA), a cell wall polymer of Gram-positive bacteria, consists of 1,3-polyglycerol-phosphate linked to glycolipid. LTA synthase (LtaS) polymerizes polyglycerol-phosphate from phosphatidylglycerol, a reaction that is essential for the growth of Gram-positive bacteria. We screened small molecule libraries for compounds inhibiting growth of Staphylococcus aureus but not of Gram-negative bacteria. Compound 1771 [2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-naphtho[2,1-b]furan-1-ylacetate] blocked phosphatidylglycerol binding to LtaS and inhibited LTA synthesis in S. aureus and in Escherichia coli expressing ltaS. Compound 1771 inhibited the growth of antibiotic-resistant Gram-positive bacteria and prolonged the survival of mice with lethal S. aureus challenge, validating LtaS as a target for the development of antibiotics.

Richter, Stefan G.; Elli, Derek; Kim, Hwan Keun; Hendrickx, Antoni P. A.; Sorg, Joseph A.; Schneewind, Olaf; Missiakas, Dominique

2013-01-01

166

Transformations of the gram-positive honey bee pathogen, Paenibacillus larvae, by electroporation  

Technology Transfer Automated Retrieval System (TEKTRAN)

In this study we developed an electrotransformation method for use with the Gram-positive bacterium Paenibacillus larvae—a deadly pathogen of honey bees. The method is substantially different from the only other electroporation method for a Paenibacillus species found in the literature. Using the ty...

167

Novel Cassette-Based Shuttle Vector System for Gram-Positive Bacteria  

Microsoft Academic Search

Virulent bacterial strains have developed complex metabolic and regulatory pathways to enable them to thrive in the in vivo environment during infection. Understanding how the regula- tory networks operate requires manipulation of many genes and expressing them temporally and spatially at different levels or under separate regulatory controls. In the case of gram- positive bacteria including staphylococci, the introduction of

Emmanuelle Charpentier; Ana I. Anton; Peter Barry; Berenice Alfonso; Yuan Fang; Richard P. Novick

2004-01-01

168

Genome-Wide Gene Order Distances Support a United Gram-Positive Bacteria  

NASA Astrophysics Data System (ADS)

We have attempted to use a Monte Carlo approach to look for small genome-wide instances of gene order conservation. Our trees show the actinobacteria as a sister group to the bulk of the firmicutes. The results are supportive of a single origin for the gram-positive cell.

House, C. H.; Fitz-Gibbon, S. T.

2010-04-01

169

Anchorless adhesins and invasins of Gram-positive bacteria: a new class of virulence factors  

Microsoft Academic Search

Bacterial adherence to and invasion of eukaryotic cells are important mechanisms of pathogenicity. Most Gram-positive bacteria interact with the components of the host extracellular matrix (ECM) to adhere to, colonize and invade cells and tissues. The bacterial proteins that bind to components of the ECM harbour signal sequences for their secretion and mechanisms of anchoring to the host cell surface.

Gursharan S Chhatwal

2002-01-01

170

Efflux-Mediated Resistance to Fluoroquinolones in Gram-Positive Bacteria and the Mycobacteria  

Microsoft Academic Search

The fluoroquinolone (FQ) group of antimicrobial agents is increasingly popular in the treatment of a variety of gram- negative infections, against which they are often highly effec- tive. FQs are traditionally less active against gram-positive pathogens, although they are clinically useful against Myco- plasma pneumonia and have been employed in the treatment of drug-resistant mycobacterial infections (5), as well as

KEITH POOLE

2000-01-01

171

Protein phosphorylation and regulation of carbon metabolism in Gram-negative versus Gram-positive bacteria  

Microsoft Academic Search

Bacteria impose regulatory mechanisms on metabolic processes to ensure that the needs of the cell are met but not exceeded. Here, we discuss the basic features of a mechanism by which carbohydrate catabolism in Gram-positive bacteria is regulated. Although the physiological consequences of this regulation are the same as in Gram-negative bacteria, the mechanism is entirely different. These regulatory processes

Milton H Saier; Sylvie Chauvaux; Josef Deutscher; Jonathan Reizer; Jing-Jing Ye

1995-01-01

172

Microarray-Based Detection of 90 Antibiotic Resistance Genes of Gram-Positive Bacteria  

Microsoft Academic Search

A disposable microarray was developed for detection of up to 90 antibiotic resistance genes in gram-positive bacteria by hybridization. Each antibiotic resistance gene is represented by two specific oligonucleotides chosen from consensus sequences of gene families, except for nine genes for which only one specific oligonucleotide could be developed. A total of 137 oligonucleotides (26 to 33 nucleotides in length

Vincent Perreten; Lorianne Vorlet-Fawer; Peter Slickers; Ralf Ehricht; Peter Kuhnert; Joachim Frey

2005-01-01

173

Antibacterial activity and mechanism of action of tick defensin against Gram-positive bacteria  

Microsoft Academic Search

Defensins are a major group of antimicrobial peptides and are found widely in vertebrates, invertebrates and plants. Invertebrate defensins have been identified from insects, scorpions, mussels and ticks. In this study, chemically synthesized tick defensin was used to further investigate the activity spectrum and mode of action of natural tick defensin. Synthetic tick defensin showed antibacterial activity against many Gram-positive

Yoshiro Nakajima; Jun Ishibashi; Fumiko Yukuhiro; Ai Asaoka; DeMar Taylor; Minoru Yamakawa

2003-01-01

174

Sorting sortases: a nomenclature proposal for the various sortases of Gram-positive bacteria  

Microsoft Academic Search

Bacterial surface proteins constitute a diverse group of molecules with important functions, such as adherence, invasion, signaling and interaction with the host immune system or the environment. In Gram-positive bacteria, many surface proteins are anchored to the cell wall envelope by an enzyme named sortase, which recognizes a conserved carboxylic sorting motif. The sequence of the prototype staphylococcal SrtA has

Shaynoor Dramsi; Patrick Trieu-Cuot; Hélène Bierne

2005-01-01

175

Gram-positive three-component antimicrobial peptide-sensing system  

Microsoft Academic Search

To survive during colonization or infection of the human body, microorganisms must circumvent mechanisms of innate host defense. Antimicrobial peptides represent a key component of innate host defense, especially in phagocytes and on epithelial surfaces. However, it is not known how the clinically important group of Gram-positive bacteria sense antimicrobial peptides to coordinate a directed defensive response. By determining the

Min Li; Yuping Lai; A. E. Villaruz; D. J. Cha; D. E. Sturdevant; Michael Otto

2007-01-01

176

Identification of Surprisingly Diverse Type IV Pili, across a Broad Range of Gram-Positive Bacteria  

PubMed Central

Background In Gram-negative bacteria, type IV pili (TFP) have long been known to play important roles in such diverse biological phenomena as surface adhesion, motility, and DNA transfer, with significant consequences for pathogenicity. More recently it became apparent that Gram-positive bacteria also express type IV pili; however, little is known about the diversity and abundance of these structures in Gram-positives. Computational tools for automated identification of type IV pilins are not currently available. Results To assess TFP diversity in Gram-positive bacteria and facilitate pilin identification, we compiled a comprehensive list of putative Gram-positive pilins encoded by operons containing highly conserved pilus biosynthetic genes (pilB, pilC). A surprisingly large number of species were found to contain multiple TFP operons (pil, com and/or tad). The N-terminal sequences of predicted pilins were exploited to develop PilFind, a rule-based algorithm for genome-wide identification of otherwise poorly conserved type IV pilins in any species, regardless of their association with TFP biosynthetic operons (http://signalfind.org). Using PilFind to scan 53 Gram-positive genomes (encoding >187,000 proteins), we identified 286 candidate pilins, including 214 in operons containing TFP biosynthetic genes (TBG+ operons). Although trained on Gram-positive pilins, PilFind identified 55 of 58 manually curated Gram-negative pilins in TBG+ operons, as well as 53 additional pilin candidates in operons lacking biosynthetic genes in ten species (>38,000 proteins), including 27 of 29 experimentally verified pilins. False positive rates appear to be low, as PilFind predicted only four pilin candidates in eleven bacterial species (>13,000 proteins) lacking TFP biosynthetic genes. Conclusions We have shown that Gram-positive bacteria contain a highly diverse set of type IV pili. PilFind can be an invaluable tool to study bacterial cellular processes known to involve type IV pilus-like structures. Its use in combination with other currently available computational tools should improve the accuracy of predicting the subcellular localization of bacterial proteins.

Roos, David S.; Pohlschroder, Mechthild

2011-01-01

177

Molecular analysis and regulation of the glnA gene of the gram-positive anaerobe Clostridium acetobutylicum.  

PubMed Central

The nucleotide sequence of a 2.0-kilobase DNA segment containing the Clostridium acetobutylicum glnA gene was determined. The upstream region of the glnA gene contained two putative extended promoter consensus sequences (p1 and p2), characteristic of gram-positive bacteria. A third putative extended gram-positive promoter consensus sequence (p3), oriented towards the glnA gene, was detected downstream of the structural gene. The sequences containing the proposed promoter regions p1 and p2 or p3 were shown to have promoter activity by subcloning into promoter probe vectors. The complete amino acid sequence (444 residues) of the C. acetobutylicum glutamine synthetase (GS) was deduced, and comparisons were made with the reported amino acid sequences of GS from other organisms. To determine whether the putative promoter p3 and a downstream region with an extensive stretch of inverted repeat sequences were involved in regulation of C. acetobutylicum glnA gene expression by nitrogen in Escherichia coli, deletion plasmids were constructed lacking p3 and various downstream sequences. Deletion of the putative promoter p3 and downstream inverted repeat sequences affected the regulation of GS and reduced the levels of GS approximately fivefold under nitrogen-limiting conditions but did not affect the repression of GS levels in cells grown under nitrogen-excess conditions.

Janssen, P J; Jones, W A; Jones, D T; Woods, D R

1988-01-01

178

Antimicrobial susceptibilities of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobial agents.  

PubMed

The susceptibilities of 265 strains of Corynebacterium species and other non-spore-forming gram-positive bacilli to 18 antimicrobial agents were tested. Most strains were susceptible to vancomycin, doxycycline, and fusidic acid. Corynebacterium jeikeium and Corynebacterium urealyticum were the most resistant organisms tested. Resistance to beta-lactams, clindamycin, erythromycin, azythromycin, ciprofloxacin and gentamicin was common among strains of Corynebacterium xerosis and Corynebacterium minutissimum. Ampicillin resistance among Listeria monocytogenes was more prevalent than previously reported. Optochin, fosfomycin, and nitrofurantoin showed very little activity against most organisms tested, but the use of nitrofurantoin as a selective agent in culture medium may prevent the recovery of some isolates. Except for the unvarying activity of vancomycin against Corynebacterium species, the antimicrobial susceptibilities of the latter to other antibiotics are usually unpredictable, such that susceptibility tests are necessary for selecting the best antimicrobial treatment. PMID:7695308

Soriano, F; Zapardiel, J; Nieto, E

1995-01-01

179

Alternating electric fields combined with activated carbon for disinfection of Gram negative and Gram positive bacteria in fluidized bed electrode system.  

PubMed

Strong electric fields for disinfection of wastewaters have been employed already for several decades. An innovative approach combining low strength (7 V/cm) alternating electric fields with a granular activated carbon fluidized bed electrode (FBE) for disinfection was presented recently. For disinfection performance of FBE several pure microbial cultures were tested: Bacillus subtilis, Bacillus subtilis subsp. subtilis, Enterococcus faecalis as representatives from Gram positive bacteria and Erwinia carotovora, Pseudomonas luteola, Pseudomonas fluorescens and Escherichia coli YMc10 as representatives from Gram negative bacteria. The alternating electric field amplitude and shape were kept constant. Only the effect of alternating electric field frequency on disinfection performance was investigated. From the bacteria tested, the Gram negative strains were more susceptible and the Gram positive microorganisms were more resistant to FBE disinfection. The collected data indicate that the efficiency of disinfection is frequency and strain dependent. During 6 h of disinfection, the decrease above 2 Log units was achieved with P. luteola and E. coli at 10 kHz and at dual frequency shift keying (FSK) modulated signal with frequencies of 10 kHz and 140 kHz. FBE technology appears to offer a new way for selective bacterial disinfection, however further optimizations are needed on treatment duration, and energy input, to improve effectiveness. PMID:24012021

Racyte, Justina; Bernard, Séverine; Paulitsch-Fuchs, Astrid H; Yntema, Doekle R; Bruning, Harry; Rijnaarts, Huub H M

2013-08-20

180

The potent antimicrobial properties of cell penetrating peptide-conjugated silver nanoparticles with excellent selectivity for Gram-positive bacteria over erythrocytes  

NASA Astrophysics Data System (ADS)

Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (Gram-positive Bacillus subtilis, Gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects.Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (Gram-positive Bacillus subtilis, Gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34254a

Liu, Lihong; Yang, Jun; Xie, Jianping; Luo, Zhentao; Jiang, Jiang; Yang, Yi Yan; Liu, Shaomin

2013-04-01

181

Susceptibilities of 428 gram-positive and -negative anaerobic bacteria to Bay y3118 compared with their susceptibilities to ciprofloxacin, clindamycin, metronidazole, piperacillin, piperacillin-tazobactam, and cefoxitin.  

PubMed Central

The susceptibilities of 428 gram-negative and gram-positive anaerobes (including selected cefoxitin-resistant strains) to Bay y3118 (a new fluoroquinolone), ciprofloxacin, clindamycin, metronidazole, cefoxitin, piperacillin, and piperacillin-tazobactam were tested. Organisms comprised 115 Bacteroides fragilis group, 116 non-B. fragilis Bacteroides, Prevotella, and Porphyromonas spp., 40 fusobacteria, 58 peptostreptococci, 48 gram-positive non-spore-forming rods, and 51 clostridia. beta-Lactamase production was demonstrated in 87% of the gram-negative rods but in none of the gram-positive organisms. Overall, Bay y3118 was the most active agent, with all organisms inhibited at an MIC of < or = 2.0 micrograms/ml (MICs for 50% [MIC50] and 90% [MIC90] of strains tested, 0.125 and 0.5 microgram/ml, respectively). By contrast, ciprofloxacin was much less active, with only 42% of strains susceptible at a breakpoint of 2.0 micrograms/ml (MIC50, 4.0 micrograms/ml; MIC90, 16.0 micrograms/ml). Metronidazole was active against all gram-negative rods, but 7% of peptostreptococci, 83% of gram-positive non-spore-forming rods, and 4% of non-Clostridium perfringens, non-Clostridium difficile clostridia were resistant to this agent (MICs, > 16.0 micrograms/ml). Clindamycin was active against 94% of Bacteroides, Prevotella, and Porphyromonas spp., 91% of peptostreptococci, and 100% of gram-positive non-spore-forming rods, but was active against only 70% of fusobacteria and 53% of clostridia. Cefoxitin was active against > or = 90% of all groups except the B. fragilis group and non-Propionibacterium acnes gram-positive non-spore-forming rods (both 85%) and C. difficile (20%). Significant enhancement of piperacillin by tazobactam was seen in all beta-lactamase-positive strains (99% susceptible; MIC90, 8.0 micrograms/ml), and all beta-lactamase-negative strains were susceptible to piperacillin (MIC90, 8.0 micrograms/ml). Clinical studies are required to delineate the role of Bay y3118 in the treatment of anaerobic infections.

Pankuch, G A; Jacobs, M R; Appelbaum, P C

1993-01-01

182

Protein transport across the cell wall of monoderm Gram-positive bacteria  

PubMed Central

Summary In monoderm (single membrane) Gram-positive bacteria, the majority of secreted proteins are first translocated across the cytoplasmic membrane into the inner wall zone. For a subset of these proteins, final destination is within the cell envelope either as membrane-anchored or cell wall-anchored proteins, whereas another subset of proteins is destined to be transported across the cell wall into the extracellular milieu. Although the cell wall is a porous structure, there is evidence that, for some proteins, transport is a regulated process. This review aims at describing what is known about the mechanisms that regulate the transport of proteins across the cell wall of monoderm Gram-positive bacteria.

Forster, Brian M.; Marquis, Helene

2012-01-01

183

Conversion of Fatty Acids by Bacillus sphaericus Like Organisms  

Microsoft Academic Search

Bacillus sphaericus species are mesophilic round-spored organisms that readily utilize fatty acid-based surfactants during growth, but their\\u000a ability to modify fatty acids is unknown. Among 57 B. sphaericus-like strains tested for fatty acid transformation activity in Wallen fermentation (WF) medium, ten converted oleic acid to\\u000a a new product determined by gas chromatography – mass spectrometry (GC-MS) to be 10-ketostearic acid

Tsung Min Kuo; Lawrence K. Nakamura; Alan C. Lanser

2002-01-01

184

Two Cases of Endogenous Endophthalmitis Caused by Gram-Positive Bacteria with Good Visual Outcome  

Microsoft Academic Search

Background: Endogenous endophthalmitis is a rare disease and its visual prognosis is poor. Case Reports: We present two patients, a 60-year-old man and a 53-year-old man, who developed endogenous endophthalmitis caused byGram-positive organismsbut recovered good vision after antibiotics and vitrectomy. Results: The first patient complained of ocular pain and visual decrease in his right eye. Ophthalmoscopy showed inflammation in the

Machiko Itoh; Junko Ikewaki; Kenichi Kimoto; Yuji Itoh; Kei Shinoda; Kazuo Nakatsuka

2010-01-01

185

Potency and Bactericidal Activity of Iclaprim against Recent Clinical Gram-Positive Isolates?  

PubMed Central

The in vitro activity of iclaprim, a novel diaminopyrimidine derivative, was evaluated against 5,937 recent gram-positive clinical isolates collected in the United States and Europe. Iclaprim demonstrated potent activity against Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]), beta-hemolytic Streptococcus spp., and Enterococcus faecalis strains tested. In addition, iclaprim exhibited bactericidal activity against all S. aureus strains tested, including MRSA.

Sader, Helio S.; Fritsche, Thomas R.; Jones, Ronald N.

2009-01-01

186

Potency and bactericidal activity of iclaprim against recent clinical gram-positive isolates.  

PubMed

The in vitro activity of iclaprim, a novel diaminopyrimidine derivative, was evaluated against 5,937 recent gram-positive clinical isolates collected in the United States and Europe. Iclaprim demonstrated potent activity against Staphylococcus aureus (including methicillin-resistant S. aureus [MRSA]), beta-hemolytic Streptococcus spp., and Enterococcus faecalis strains tested. In addition, iclaprim exhibited bactericidal activity against all S. aureus strains tested, including MRSA. PMID:19289528

Sader, Helio S; Fritsche, Thomas R; Jones, Ronald N

2009-03-16

187

Novel antibacterial agents for the treatment of serious Gram-positive infections  

Microsoft Academic Search

With the continuing development of clinical drug resistance among bacteria and the advent of resistance to the recently released agents quinupristin- dalfopristin and linezolid, the need for new, effective agents to treat multi- drug-resistant Gram-positive infections remains important. This review focuses on agents presently in clinical development for the treatment of serious multidrug-resistant staphylococcal, enterococcal and pneumococcal infections, including methicillin-resistant

Darren Abbanat; Mark Macielag; Karen Bush

2003-01-01

188

In vitro Activity of Biapenem against Recent Gram-Negative and Gram-Positive Clinical Isolates  

Microsoft Academic Search

The in vitro activity of biapenem, a new carbapenem, against 535 clinical recent isolates was compared with those of other antibiotics. Biapenem showed broad-spectrum activity against gram-negative and gram-positive clinical isolates. The new carbapenem was more active than imipenem against members of the family Enterobacteriaceae with MIC90S ranging from 0.12 to 2 mg\\/l and from 0.25 to 4 mg\\/l, respectively.

Giovanni Bonfiglio; Giuseppa Maccarone; Maria Lina Mezzatesta; Angela Privitera; Vincenzo Carciotto; Maria Santagati; Stefania Stefani; Giuseppe Nicoletti

1997-01-01

189

In Vitro Activities of RWJ-54428 (MC02,479) against Multiresistant Gram-Positive Bacteria  

Microsoft Academic Search

RWJ-54428 (MC-02,479) is a new cephalosporin with a high level of activity against gram-positive bacteria. In a broth microdilution susceptibility test against methicillin-resistant Staphylococcus aureus (MRSA), RWJ- 54428 was as active as vancomycin, with an MIC at which 90% of isolates are inhibited (MIC90 )o f 2mg\\/ml. For coagulase-negative staphylococci, RWJ-54428 was 32 times more active than imipenem, with an

SUZANNE CHAMBERLAND; JOHANNE BLAIS; MONICA HOANG; CYNTHIA DINH; DYLAN COTTER; EMMETT BOND; CARLA GANNON; CRAIG PARK; FRANCOIS MALOUIN; MICHAEL N. DUDLEY

2001-01-01

190

In Vitro Activities of Two Ketolides, HMR 3647 and HMR 3004, against Gram-Positive Bacteria  

Microsoft Academic Search

The in vitro activities of two new ketolides, HMR 3647 and HMR 3004, were tested by the agar dilution method against 280 strains of gram-positive bacteria with different antibiotic susceptibility profiles, including Staphylococcus aureus, Enterococcus faecalis, Enterococcus faecium, Streptococcus spp. (group A streptococci, group B streptococci, Streptococcus pneumoniae, and alpha-hemolytic streptococci). Seventeen erythromycin- susceptible (Em s ), methicillin-susceptible S. aureus

KUMTHORN MALATHUM; TERESA M. COQUE; KAVINDRA V. SINGH; BARBARA E. MURRAY

1999-01-01

191

Plasmid vectors for Gram-positive bacteria switching from high to low copy number  

Microsoft Academic Search

A set of vectors for Gram-positive bacteria was constructed with a new feature which enables the switching down of their copy number per cell. These vectors carry the replication region of pAM?1, containing a gene essential for replication, repE, and its regulator, copF The latter gene was inactivated by inserting a linker into its unique KpnI site. Since copF downregulates

Pierre Renault; Gerard Corthier; Nathalie Goupil; Christine Delorme; S. Dusko Ehrlich

1996-01-01

192

Drosophila Toll is activated by Gram-positive bacteria through a circulating peptidoglycan recognition protein  

Microsoft Academic Search

Microbial infection activates two distinct intracellular signalling cascades in the immune-responsive fat body of Drosophila. Gram-positive bacteria and fungi predominantly induce the Toll signalling pathway, whereas Gram-negative bacteria activate the Imd pathway. Loss-of-function mutants in either pathway reduce the resistance to corresponding infections. Genetic screens have identified a range of genes involved in these intracellular signalling cascades, but how they

Tatiana Michel; Jean-Marc Reichhart; Jules A. Hoffmann; Julien Royet

2001-01-01

193

Comparative In Vitro Activities of Daptomycin and Vancomycin against Resistant Gram-Positive Pathogens  

Microsoft Academic Search

The in vitro activity of daptomycin against 224 current gram-positive clinical isolates including vancomycin- resistant Enterococcus faecium (VREF), methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resis- tant Staphylococcus spp. (MRSS), and penicillin-resistant Streptococcus pneumoniae (PRSP) was evaluated. The MICs at which 90% of isolates are inhibited for daptomycin and vancomycin, respectively, were as follows: MRSA, 1 and 2 mg\\/ml; MRSS, 1 and 4

D. R. Snydman; N. V. Jacobus; L. A. McDermott; J. R. Lonks; J. M. Boyce

2000-01-01

194

Distribution of the antiseptic-resistance gene qacE? 1 in Gram-positive bacteria  

Microsoft Academic Search

The distribution of the antiseptic-resistance genes qacE and qacE?1, originally isolated from Gram-negative bacteria, was studied in a large number of Gram-positive bacteria by a method that included the polymerase chain reaction. A total of 151 strains of Staphylococcus and Enterococcus, isolated from clinical sources and obtained from the Japanese Collection of Microorganisms, was used in this analysis. We found

Hitoshi Kazama; Hajime Hamashima; Masanori Sasatsu; Taketoshi Arai

1998-01-01

195

Gram-positive infections: pharmacy issues and strategy for quinupristin\\/dalfopristin  

Microsoft Academic Search

The development of the first streptogramin antibiotic, quinupristin\\/dalfopristin represents an attempt to bring new antimicrobial strategies on line to combat the menacing problem of Gram-positive–resistant bacteria. With introduction to the medical center formulary, the pharmacy will need to be aware of several practical issues surrounding the use of quinupristin\\/dalfopristin. Cost and unit size will be important issues. Initially, this drug

John C Rotschafer; David H Wright; Gigi H Brown

1999-01-01

196

Purification Techniques of Bacteriocins from Lactic Acid Bacteria and Other Gram-Positive Bacteria  

Microsoft Academic Search

\\u000a The search for new antimicrobial peptides produced by lactic acid ­bacteria and other Gram-positive microorganisms has become\\u000a an interesting field of research in the past decades. The fact that bacteriocins are active against numerous foodborne and\\u000a human pathogens, are produced by generally regarded as safe (GRAS) microorganisms, and are readily degraded by proteolytic\\u000a host systems makes them attractive candidates for

Lucila Saavedra; Fernando Sesma

2011-01-01

197

Genome sequence of the diazotrophic Gram-positive rhizobacterium Paenibacillus riograndensis SBR5(T).  

PubMed

Paenibacillus riograndensis SBR5(T), a nitrogen-fixing Gram-positive rhizobacterium isolated from a wheat field in the south of Brazil, has a great potential for agricultural applications due to its plant growth promotion effects. Here we present the draft genome sequence of P. riograndensis SBR5(T). Its 7.37-Mb genome encodes determinants of the diazotrophic lifestyle and plant growth promotion, such as nitrogen fixation, antibiotic resistance, nitrate utilization, and iron uptake. PMID:22038959

Beneduzi, Anelise; Campos, Samanta; Ambrosini, Adriana; de Souza, Rocheli; Granada, Camille; Costa, Pedro; Arruda, Letícia; Moreira, Fernanda; Vargas, Luciano K; Weiss, Vinícius; Tieppo, Eduardo; Faoro, Helisson; de Souza, Emanuel M; Pedrosa, Fábio O; Passaglia, Luciane M P

2011-11-01

198

Genome Sequence of the Diazotrophic Gram-Positive Rhizobacterium Paenibacillus riograndensis SBR5T  

PubMed Central

Paenibacillus riograndensis SBR5T, a nitrogen-fixing Gram-positive rhizobacterium isolated from a wheat field in the south of Brazil, has a great potential for agricultural applications due to its plant growth promotion effects. Here we present the draft genome sequence of P. riograndensis SBR5T. Its 7.37-Mb genome encodes determinants of the diazotrophic lifestyle and plant growth promotion, such as nitrogen fixation, antibiotic resistance, nitrate utilization, and iron uptake.

Beneduzi, Anelise; Campos, Samanta; Ambrosini, Adriana; de Souza, Rocheli; Granada, Camille; Costa, Pedro; Arruda, Leticia; Moreira, Fernanda; Vargas, Luciano K.; Weiss, Vinicius; Tieppo, Eduardo; Faoro, Helisson; de Souza, Emanuel M.; Pedrosa, Fabio O.; Passaglia, Luciane M. P.

2011-01-01

199

Leucobacter komagatae gen. ~ov., sp. ~ov., a New Aerobic Gram-Positive7 Nonsporulating Rod with 2,4-Diarninobutyric Acid in the Cell Wall  

Microsoft Academic Search

A new aerobic, gram-positive, nonsporulating rod-shaped organism is described. Strain IF0 15245T (T = type strain) has the following characteristics: the menaquinone contains a side chain with 11 isoprenyl units; the guanine-plus-cytosine content of the DNA is 66.2 mol%; 2,4-diaminobutyric acid, glutamic acid, alanine, glycine, and y-aminobutyric acid are present in the cell wall at a molar ratio of ca.

MARIKO TAKEUCHI; NORBERT WEISS; PETER SCHUMA; AKIRA YOKOTA' T

200

Telavancin versus Standard Therapy for Treatment of Complicated Skin and Skin Structure Infections Caused by Gram-Positive Bacteria: FAST 2 Study  

Microsoft Academic Search

Telavancin is a bactericidal lipoglycopeptide with a multifunctional mechanism of action. We conducted a randomized, double blind, active-control phase II trial. Patients >18 years of age with complicated skin and skin structure infections caused by suspected or confirmed gram-positive organisms were randomized to receive either telavancin at 10 mg\\/kg intravenously every 24 h (q24h) or standard therapy (antistaphylococcal penicillin at

Martin E. Stryjewski; Vivian H. Chu; William D. O'Riordan; Brian L. Warren; Lala M. Dunbar; David M. Young; Marc Vallee; Vance G. Fowler; J. Morganroth; S. L. Barriere; M. M. Kitt; G. R. Corey

2006-01-01

201

Benfang Lei's research on heme acquisition in Gram-positive pathogens and bacterial pathogenesis  

PubMed Central

Benfang Lei’s laboratory conducts research on pathogenesis of human pathogen Group A Streptococcus (GAS) and horse pathogen Streptococcus equi (S. equi). His current research focuses on heme acquisition in Gram-positive pathogens and molecular mechanism of GAS and S. equi pathogenesis. Heme is an important source of essential iron for bacterial pathogens. Benfang Lei and colleagues identified the first cell surface heme-binding protein in Gram-positive pathogens and the heme acquisition system in GAS, demonstrated direct heme transfer from one protein to another, demonstrated an experimental pathway of heme acquisition by the Staphylococcus aureus Isd system, elucidated the activated heme transfer mechanism, and obtained evidence for a chemical mechanism of direct axial ligand displacement during the Shp-to-HtsA heme transfer reaction. These findings have considerably contributed to the progress that has been made over recent years in understanding the heme acquisition process in Gram-positive pathogens. Pathogenesis of GAS is mediated by an abundance of extracellular proteins, and pathogenic role and functional mechanism are not known for many of these virulence factors. Lei laboratory identified a secreted protein of GAS as a CovRS-regulated virulence factor that is a protective antigen and is critical for GAS spreading in the skin and systemic dissemination. These studies may lead to development of novel strategies to prevent and treat GAS infections.

Lei, Benfang

2010-01-01

202

Ambuic Acid Inhibits the Biosynthesis of Cyclic Peptide Quormones in Gram-Positive Bacteria ?  

PubMed Central

Quorum sensing is a cell-density-dependent regulatory system in gram-positive bacteria and is often regulated by cyclic peptides called “quormones,” which function as extracellular communication signals. With an aim to discover an antipathogenic agent targeting quorum sensing in gram-positive bacteria, we screened 153 samples of fungal butanol extracts with the guidance of the inhibition of quorum-sensing-mediated gelatinase production in Enterococcus faecalis. Following the screenings, we found that ambuic acid, a known secondary fungal metabolite, inhibited the quorum-sensing-mediated gelatinase production without influencing the growth of E. faecalis. We further demonstrated that ambuic acid targeted the biosynthesis of a cyclic peptide quormone called gelatinase biosynthesis-activating pheromone. Furthermore, ambuic acid also inhibited the biosynthesis of the cyclic peptide quormones of Staphylococcus aureus and Listeria innocua. These results suggest the potential use of ambuic acid as a lead compound of antipathogenic drugs that target the quorum-sensing-mediated virulence expression of gram-positive bacteria.

Nakayama, Jiro; Uemura, Yumi; Nishiguchi, Kenzo; Yoshimura, Norito; Igarashi, Yasuhiro; Sonomoto, Kenji

2009-01-01

203

Multiple Responses of Gram-Positive and Gram-Negative Bacteria to Mixture of Hydrocarbons  

PubMed Central

Most of our knowledge about pollutants and the way they are biodegraded in the environment has previously been shaped by laboratory studies using hydrocarbon-degrading bacterial strains isolated from polluted sites. In present study Gram-positive (Mycobacterium sp. IBBPo1, Oerskovia sp. IBBPo2, Corynebacterium sp. IBBPo3) and Gram-negative (Chryseomonas sp. IBBPo7, Pseudomonas sp. IBBPo10, Burkholderia sp. IBBPo12) bacteria, isolated from oily sludge, were found to be able to tolerate pure and mixture of saturated hydrocarbons, as well as pure and mixture of monoaromatic and polyaromatic hydrocarbons. Isolated Gram-negative bacteria were more tolerant to mixture of saturated (n-hexane, n-hexadecane, cyclohexane), monoaromatic (benzene, toluene, ethylbenzene) and polyaromatic (naphthalene, 2-methylnaphthalene, fluorene) hydrocarbons than Gram-positive bacteria. There were observed cellular and molecular modifications induced by mixture of saturated, monoaromatic and polyaromatic hydrocarbons to Gram-positive and Gram-negative bacteria. These modifications differ from one strain to another and even for the same bacterial strain, according to the nature of hydrophobic substrate.

Marilena Lazaroaie, Mihaela

2010-01-01

204

Critical cell wall hole size for lysis in Gram-positive bacteria.  

PubMed

Gram-positive bacteria can transport molecules necessary for their survival through holes in their cell wall. The holes in cell walls need to be large enough to let critical nutrients pass through. However, the cell wall must also function to prevent the bacteria's membrane from protruding through a large hole into the environment and lysing the cell. As such, we hypothesize that there exists a range of cell wall hole sizes that allow for molecule transport but prevent membrane protrusion. Here, we develop and analyse a biophysical theory of the response of a Gram-positive cell's membrane to the formation of a hole in the cell wall. We predict a critical hole size in the range of 15-24 nm beyond which lysis occurs. To test our theory, we measured hole sizes in Streptococcus pyogenes cells undergoing enzymatic lysis via transmission electron microscopy. The measured hole sizes are in strong agreement with our theoretical prediction. Together, the theory and experiments provide a means to quantify the mechanisms of death of Gram-positive cells via enzymatically mediated lysis and provides insights into the range of cell wall hole sizes compatible with bacterial homeostasis. PMID:23303219

Mitchell, Gabriel J; Wiesenfeld, Kurt; Nelson, Daniel C; Weitz, Joshua S

2013-01-09

205

Surface Proteins of Gram-Positive Pathogens: Using Crystallography to Uncover Novel Features in Drug and Vaccine Candidates  

NASA Astrophysics Data System (ADS)

Proteins displayed on the cell surfaces of pathogenic organisms are the front-line troops of bacterial attack, playing critical roles in colonization, infection and virulence. Although such proteins can often be recognized from genome sequence data, through characteristic sequence motifs, their functions are often unknown. One such group of surface proteins is attached to the cell surface of Gram-positive pathogens through the action of sortase enzymes. Some of these proteins are now known to form pili: long filamentous structures that mediate attachment to human cells. Crystallographic analyses of these and other cell surface proteins have uncovered novel features in their structure, assembly and stability, including the presence of inter- and intramolecular isopeptide crosslinks. This improved understanding of structures on the bacterial cell surface offers opportunities for the development of some new drug targets and for novel approaches to vaccine design.

Baker, Edward N.; Proft, Thomas; Kang, Haejoo

206

Functional Expression of Enterobacterial O-Polysaccharide Biosynthesis Enzymes in Bacillus subtilis  

Microsoft Academic Search

The expression of heterologous bacterial glycosyltransferases is of interest for potential application in the emerging field of carbohydrate engineering in gram-positive organisms. To assess the feasibility of using enzymes from gram-negative bacteria, the functional expression of the genes wbaP (formerly rfbP), wecA (formerly rfe), and wbbO (formerly rfbF) from enterobacterial lipopolysaccharide O-polysaccharide biosynthe- sis pathways was examined in Bacillus subtilis.

Christina Schaffer; Thomas Wugeditsch; Paul Messner; Chris Whitfield

2002-01-01

207

Amino acid addition to Vibrio cholerae LPS establishes a link between surface remodeling in Gram-positive and Gram-negative bacteria  

PubMed Central

Historically, the O1 El Tor and classical biotypes of Vibrio cholerae have been differentiated by their resistance to the antimicrobial peptide polymyxin B. However, the molecular mechanisms associated with this phenotypic distinction have remained a mystery for 50 y. Both Gram-negative and Gram-positive bacteria modify their cell wall components with amine-containing substituents to reduce the net negative charge of the bacterial surface, thereby promoting cationic antimicrobial peptide resistance. In the present study, we demonstrate that V. cholerae modify the lipid A anchor of LPS with glycine and diglycine residues. This previously uncharacterized lipid A modification confers polymyxin resistance in V. cholerae El Tor, requiring three V. cholerae proteins: Vc1577 (AlmG), Vc1578 (AlmF), and Vc1579 (AlmE). Interestingly, the protein machinery required for glycine addition is reminiscent of the Gram-positive system responsible for d-alanylation of teichoic acids. Such machinery was not thought to be used by Gram-negative organisms. V. cholerae O1 El Tor mutants lacking genes involved in transferring glycine to LPS showed a 100-fold increase in sensitivity to polymyxin B. This work reveals a unique lipid A modification and demonstrates a charge-based remodeling strategy shared between Gram-positive and Gram-negative organisms.

Hankins, Jessica V.; Madsen, James A.; Giles, David K.; Brodbelt, Jennifer S.; Trent, M. Stephen

2012-01-01

208

Fighting infections due to multidrug-resistant Gram-positive pathogens.  

PubMed

Growing bacterial resistance in Gram-positive pathogens means that what were once effective and inexpensive treatments for infections caused by these bacteria are now being seriously questioned, including penicillin and macrolides for use against pneumococcal infections and-in hospitals-oxacillin for use against staphylococcal infections. As a whole, multidrug-resistant (MDR) Gram-positive pathogens are rapidly becoming an urgent and sometimes unmanageable clinical problem. Nevertheless, and despite decades of research into the effects of antibiotics, the actual risk posed to human health by antibiotic resistance has been poorly defined; the lack of reliable data concerning the outcomes resulting from antimicrobial resistance stems, in part, from problems with study designs and the methods used in resistence determination. Surprisingly little is known, too, about the actual effectiveness of the many types of intervention aimed at controlling antibiotic resistance. New antibiotics active against MDR Gram-positive pathogens have been recently introduced into clinical practice, and the antibiotic pipeline contains additional compounds at an advanced stage of development, including new glycopeptides, new anti-methicillin-resistant Staphylococcus aureus (MRSA) beta-lactams, and new diaminopyrimidines. Many novel antimicrobial agents are likely to be niche products, endowed with narrow antibacterial spectra and/or targeted at specific clinical problems. Therefore, an important educational goal will be to change the current, long-lasting attitudes of both physicians and customers towards broad-spectrum and multipurpose compounds. Scientific societies, such as the European Society of Clinical Microbiology and Infectious Diseases (ESCMID), must play a leading role in this process. PMID:19335367

Cornaglia, G

2009-03-01

209

The twin-arginine translocation (Tat) systems from Bacillus subtilis display a conserved mode of complex organization and similar substrate recognition requirements.  

PubMed

The twin arginine translocation (Tat) system transports folded proteins across the bacterial plasma membrane. In Gram-negative bacteria, membrane-bound TatABC subunits are all essential for activity, whereas Gram-positive bacteria usually contain only TatAC subunits. In Bacillus subtilis, two TatAC-type systems, TatAdCd and TatAyCy, operate in parallel with different substrate specificities. Here, we show that they recognize similar signal peptide determinants. Both systems translocate green fluorescent protein fused to three distinct Escherichia coli Tat signal peptides, namely DmsA, AmiA and MdoD, and mutagenesis of the DmsA signal peptide confirmed that both Tat pathways recognize similar targeting determinants within Tat signals. Although another E. coli Tat substrate, trimethylamine N-oxide reductase, was translocated by TatAdCd but not by TatAyCy, we conclude that these systems are not predisposed to recognize only specific Tat signal peptides, as suggested by their narrow substrate specificities in B. subtilis. We also analysed complexes involved in the second Tat pathway in B. subtilis, TatAyCy. This revealed a discrete TatAyCy complex together with a separate, homogeneous, approximately 200 kDa TatAy complex. The latter complex differs significantly from the corresponding E. coli TatA complexes, pointing to major structural differences between Tat complexes from Gram-negative and Gram-positive organisms. Like TatAd, TatAy is also detectable in the form of massive cytosolic complexes. PMID:19049517

Barnett, James P; van der Ploeg, René; Eijlander, Robyn T; Nenninger, Anja; Mendel, Sharon; Rozeboom, Rense; Kuipers, Oscar P; van Dijl, Jan Maarten; Robinson, Colin

2008-11-25

210

Identification and Characterization of a Novel-type Ferric Siderophore Reductase from a Gram-positive Extremophile*  

PubMed Central

Iron limitation is one major constraint of microbial life, and a plethora of microbes use siderophores for high affinity iron acquisition. Because specific enzymes for reductive iron release in Gram-positives are not known, we searched Firmicute genomes and found a novel association pattern of putative ferric siderophore reductases and uptake genes. The reductase from the schizokinen-producing alkaliphile Bacillus halodurans was found to cluster with a ferric citrate-hydroxamate uptake system and to catalyze iron release efficiently from Fe[III]-dicitrate, Fe[III]-schizokinen, Fe[III]-aerobactin, and ferrichrome. The gene was hence named fchR for ferric citrate and hydroxamate reductase. The tightly bound [2Fe-2S] cofactor of FchR was identified by UV-visible, EPR, CD spectroscopy, and mass spectrometry. Iron release kinetics were determined with several substrates by using ferredoxin as electron donor. Catalytic efficiencies were strongly enhanced in the presence of an iron-sulfur scaffold protein scavenging the released ferrous iron. Competitive inhibition of FchR was observed with Ga(III)-charged siderophores with Ki values in the micromolar range. The principal catalytic mechanism was found to couple increasing Km and KD values of substrate binding with increasing kcat values, resulting in high catalytic efficiencies over a wide redox range. Physiologically, a chromosomal fchR deletion led to strongly impaired growth during iron limitation even in the presence of ferric siderophores. Inductively coupled plasma-MS analysis of ?fchR revealed intracellular iron accumulation, indicating that the ferric substrates were not efficiently metabolized. We further show that FchR can be efficiently inhibited by redox-inert siderophore mimics in vivo, suggesting that substrate-specific ferric siderophore reductases may present future targets for microbial pathogen control.

Miethke, Marcus; Pierik, Antonio J.; Peuckert, Florian; Seubert, Andreas; Marahiel, Mohamed A.

2011-01-01

211

Identification and characterization of a novel-type ferric siderophore reductase from a gram-positive extremophile.  

PubMed

Iron limitation is one major constraint of microbial life, and a plethora of microbes use siderophores for high affinity iron acquisition. Because specific enzymes for reductive iron release in gram-positives are not known, we searched Firmicute genomes and found a novel association pattern of putative ferric siderophore reductases and uptake genes. The reductase from the schizokinen-producing alkaliphile Bacillus halodurans was found to cluster with a ferric citrate-hydroxamate uptake system and to catalyze iron release efficiently from Fe[III]-dicitrate, Fe[III]-schizokinen, Fe[III]-aerobactin, and ferrichrome. The gene was hence named fchR for ferric citrate and hydroxamate reductase. The tightly bound [2Fe-2S] cofactor of FchR was identified by UV-visible, EPR, CD spectroscopy, and mass spectrometry. Iron release kinetics were determined with several substrates by using ferredoxin as electron donor. Catalytic efficiencies were strongly enhanced in the presence of an iron-sulfur scaffold protein scavenging the released ferrous iron. Competitive inhibition of FchR was observed with Ga(III)-charged siderophores with K(i) values in the micromolar range. The principal catalytic mechanism was found to couple increasing K(m) and K(D) values of substrate binding with increasing k(cat) values, resulting in high catalytic efficiencies over a wide redox range. Physiologically, a chromosomal fchR deletion led to strongly impaired growth during iron limitation even in the presence of ferric siderophores. Inductively coupled plasma-MS analysis of ?fchR revealed intracellular iron accumulation, indicating that the ferric substrates were not efficiently metabolized. We further show that FchR can be efficiently inhibited by redox-inert siderophore mimics in vivo, suggesting that substrate-specific ferric siderophore reductases may present future targets for microbial pathogen control. PMID:21051545

Miethke, Marcus; Pierik, Antonio J; Peuckert, Florian; Seubert, Andreas; Marahiel, Mohamed A

2010-11-04

212

Interfacial charge transfer between CdTe quantum dots and gram negative vs gram positive bacteria.  

PubMed

Oxidative toxicity of semiconductor and metal nanomaterials to cells has been well established. However, it may result from many different mechanisms, some requiring direct cell contact and others resulting from the diffusion of reactive species in solution. Published results are contradictory due to differences in particle preparation, bacterial strain, and experimental conditions. It has been recently found that C(60) nanoparticles can cause direct oxidative damage to bacterial proteins and membranes, including causing a loss of cell membrane potential (depolarization). However, this did not correlate with toxicity. In this study we perform a similar analysis using fluorescent CdTe quantum dots, adapting our tools to make use of the particles' fluorescence. We find that two Gram positive strains show direct electron transfer to CdTe, resulting in changes in CdTe fluorescence lifetimes. These two strains also show changes in membrane potential upon nanoparticle binding. Two Gram negative strains do not show these effects-nevertheless, they are over 10-fold more sensitive to CdTe than the Gram positives. We find subtoxic levels of Cd(2+) release from the particles upon irradiation of the particles, but significant production of hydroxyl radicals, suggesting that the latter is a major source of toxicity. These results help establish mechanisms of toxicity and also provide caveats for use of certain reporter dyes with fluorescent nanoparticles which will be of use to anyone performing these assays. The findings also suggest future avenues of inquiry into electron transfer processes between nanomaterials and bacteria. PMID:20085260

Dumas, Eve; Gao, Cherry; Suffern, Diana; Bradforth, Stephen E; Dimitrijevic, Nada M; Nadeau, Jay L

2010-02-15

213

Agreement Between Deoxyribonucleic Acid Base Composition and Taxometric Classification of Gram-Positive Cocci.  

PubMed

Silvestri, L. G. (Università Statale, Milan, Italy), and L. R. Hill. Agreement between deoxyribonucleic acid base composition and taxometric classification of gram-positive cocci. J. Bacteriol. 90:136-140. 1965.-It had been previously proposed, from taxometric analyses, that gram-positive, catalase-positive cocci be divided into two subgroups. Thirteen strains, representative of both subgroups, were examined for deoxyribonucleic acid (DNA) base composition, determined from melting temperatures. Per cent GC (guanine + cytosine/total bases) values fell into two groups: 30.8 to 36.5% GC and 69 to 75% GC. Strains with low per cent GC values belonged to the Staphylococcus aureus-S. saprophyticus-S. lactis taxometric subgroups, and those with high per cent GC values belonged to the S. roseus-S. afermentans subgroup. The hypothetical nature of any classification is emphasized, and, in the present work, the hypothesis derived from taxometric analyses of division into two subgroups is confirmed by the study of DNA base ratios. The two subgroups correspond, respectively, to the genera Staphylococcus and Micrococcus. PMID:16562008

Silvestri, L G; Hill, L R

1965-07-01

214

Agreement Between Deoxyribonucleic Acid Base Composition and Taxometric Classification of Gram-Positive Cocci1  

PubMed Central

Silvestri, L. G. (Università Statale, Milan, Italy), and L. R. Hill. Agreement between deoxyribonucleic acid base composition and taxometric classification of gram-positive cocci. J. Bacteriol. 90:136–140. 1965.—It had been previously proposed, from taxometric analyses, that gram-positive, catalase-positive cocci be divided into two subgroups. Thirteen strains, representative of both subgroups, were examined for deoxyribonucleic acid (DNA) base composition, determined from melting temperatures. Per cent GC (guanine + cytosine/total bases) values fell into two groups: 30.8 to 36.5% GC and 69 to 75% GC. Strains with low per cent GC values belonged to the Staphylococcus aureus–S. saprophyticus–S. lactis taxometric subgroups, and those with high per cent GC values belonged to the S. roseus–S. afermentans subgroup. The hypothetical nature of any classification is emphasized, and, in the present work, the hypothesis derived from taxometric analyses of division into two subgroups is confirmed by the study of DNA base ratios. The two subgroups correspond, respectively, to the genera Staphylococcus and Micrococcus.

Silvestri, L. G.; Hill, L. R.

1965-01-01

215

Interfacial charge transfer between CdTe quantum dots and Gram negative vs. Gram positive bacteria.  

SciTech Connect

Oxidative toxicity of semiconductor and metal nanomaterials to cells has been well established. However, it may result from many different mechanisms, some requiring direct cell contact and others resulting from the diffusion of reactive species in solution. Published results are contradictory due to differences in particle preparation, bacterial strain, and experimental conditions. It has been recently found that C{sub 60} nanoparticles can cause direct oxidative damage to bacterial proteins and membranes, including causing a loss of cell membrane potential (depolarization). However, this did not correlate with toxicity. In this study we perform a similar analysis using fluorescent CdTe quantum dots, adapting our tools to make use of the particles fluorescence. We find that two Gram positive strains show direct electron transfer to CdTe, resulting in changes in CdTe fluorescence lifetimes. These two strains also show changes in membrane potential upon nanoparticle binding. Two Gram negative strains do not show these effects - nevertheless, they are over 10-fold more sensitive to CdTe than the Gram positives. We find subtoxic levels of Cd{sup 2+} release from the particles upon irradiation of the particles, but significant production of hydroxyl radicals, suggesting that the latter is a major source of toxicity. These results help establish mechanisms of toxicity and also provide caveats for use of certain reporter dyes with fluorescent nanoparticles which will be of use to anyone performing these assays. The findings also suggest future avenues of inquiry into electron transfer processes between nanomaterials and bacteria.

Dumas, E.; Gao, C.; Suffern, D.; Bradforth, S. E.; Dimitrejevic, N. M.; Nadeau, J. L.; McGill Univ.; Univ. of Southern California

2010-01-01

216

Gene homogeneity for aminoglycoside-modifying enzymes in gram-positive cocci.  

PubMed Central

Aminoglycoside-resistant strains of Staphylococcus and Enterococcus, approximately 500 of each, were screened by dot blot hybridization for the presence of genes encoding aminoglycoside-modifying enzymes. The MICs of various aminoglycosides for the strains were determined, and the enzyme contents of the cells were inferred from the resistance phenotypes. The agreements (in percent) of the hybridization results with the deduced enzyme contents for Staphylococcus and Enterococcus species were, respectively, 80 and 87.6 for ANT(6) (aminoglycoside nucleotidyltransferase), 99.8 and 100 for both APH(3') (aminoglycoside phosphotransferase) and APH(2")-AAC(6') (aminoglycoside acetyltransferase), and 100 and 100 for ANT(4'). The weak correlation obtained with the probe for ANT(6) was due to the fact that gram-positive cocci can also be streptomycin resistant by synthesis of APH(3") or ANT(3")(9) and by ribosomal mutation. The remaining probes appeared to be specific: they hybridized with all the resistant clinical isolates but not with the susceptible strains. These results indicate that, except for streptomycin, nucleic acid hybridization is a valid approach for the detection and characterization of aminoglycoside resistance in gram-positive cocci.

Ounissi, H; Derlot, E; Carlier, C; Courvalin, P

1990-01-01

217

Bioengineered Nisin A Derivatives with Enhanced Activity against Both Gram Positive and Gram Negative Pathogens  

PubMed Central

Nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G), with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E) with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria.

Field, Des; Begley, Maire; O'Connor, Paula M.; Daly, Karen M.; Hugenholtz, Floor; Cotter, Paul D.; Hill, Colin; Ross, R. Paul

2012-01-01

218

[Comparative urinary bactericidal activity of oral antibiotics against gram-positive pathogens].  

PubMed

In routine bacteriological laboratories the antibacterial activity of antibiotics is determined by in vitro testing, usually by disk-diffusion test. However, in vitro testing does not always reflect antibacterial efficiency of antibiotics in vivo. In this investigation, the urine samples obtained in a single oral dose pharmacokinetic study were examined for their bactericidal activity against a range of relevant Gram-positive urinary tract pathogens. Urinary bactericidal activity of linezolid had been previously compared with ciprofloxacin but not with other oral antibiotics such as beta-lactams. Linezolid showed satisfactory urinary bactericidal titres throughout the whole testing period against all Gram-positive cocci. Fluoroquinolones displayed high and persisting levels of urinary bactericidal activity against staphylococci, but their activity against enterococci was weaker. According to the results of ex-vivo testing amoxycillin could be recommended only for infections caused by E. faecalis. Amoxycillin combined with clavulanic acid can be considered as a therapeutic option for infections caused by S. saprophyticus and E. faecalis. Older cephalosporins had high titres only against S. saprophyticus. Their drawback is a short elimination half-time in urine resulting in rapid decrease of urinary bactericidal titers during dosing interval. Furthermore, they do not show activity against enterococci due to their intrinsic resistance to cephalosporins. PMID:22930932

Bedeni?, Branka; Budimir, Ana; Gveri?, Ana; Plecko, Vanda; Vranes, Jasmina; Bubonja-Sonje, Marina; Kaleni?, Smilja

219

The potent antimicrobial properties of cell penetrating peptide-conjugated silver nanoparticles with excellent selectivity for gram-positive bacteria over erythrocytes.  

PubMed

Silver nanoparticles are of great interest for use as antimicrobial agents. Studies aimed at producing potent nano-silver biocides have focused on manipulation of particle size, shape, composition and surface charge. Here, we report the cell penetrating peptide catalyzed formation of antimicrobial silver nanoparticles in N,N-dimethylformamide. The novel nano-composite demonstrated a distinctly enhanced biocidal effect toward bacteria (gram-positive Bacillus subtilis, gram-negative Escherichia coli) and pathogenic yeast (Candida albicans), as compared to triangular and extremely small silver nanoparticles. In addition, a satisfactory biocompatibility was verified by a haemolysis test. Our results provide a paradigm in developing strategies that can maximize the silver nanoparticle application potentials while minimizing the toxic effects. PMID:23525222

Liu, Lihong; Yang, Jun; Xie, Jianping; Luo, Zhentao; Jiang, Jiang; Yang, Yi Yan; Liu, Shaomin

2013-03-22

220

Antibiotic MIC\\/MBC analysis of Bacillus -based commercial insecticides: use of bioreduction and DNA-based assays  

Microsoft Academic Search

Bacillus thuringiensis   subsp israelensis (Bti) and subsp kurstaki (Btk); (2) vegetative cells derived from these BT products; and (3) Gram-positive and Gram-negative bacteria used as controls.\\u000a The XTT-kinetic assay improved sensitivity and early reading of MIC breakpoints. The conventional colony count method for\\u000a determining minimal bactericidal concentration (MBC) was used to validate a multi-sample dot-blot assay in which organisms\\u000a in

V L Seligy; J M Rancourt

1999-01-01

221

Rapid analysis of Gram-positive bacteria in water via membrane filtration coupled with nanoprobe-based MALDI-MS  

Microsoft Academic Search

Matrix-assisted laser desorption\\/ionization (MALDI) mass spectrometry (MS) is challenging when it is directly applied to identify\\u000a bacteria in water. This study demonstrates a rapid, sensitive, and selective technique for detection of Gram-positive bacteria\\u000a in water. It involves a combination of membrane filtration (MF) and vancomycin-conjugated magnetite nanoparticles (VNPs) to\\u000a selectively separate and concentrate Gram-positive bacteria in tap water and reservoir

Shuping Li; Zhongxian Guo; Hui-Fen Wu; Ying Liu; Zhaoguang Yang; Chee Hoe Woo

2010-01-01

222

Function of the drosophila pattern-recognition receptor PGRP-SD in the detection of Gram-positive bacteria  

Microsoft Academic Search

The activation of an immune response requires recognition of microorganisms by host receptors. In drosophila, detection of Gram-positive bacteria is mediated by cooperation between the peptidoglycan-recognition protein-SA (PGRP-SA) and Gram-negative binding protein 1 (GNBP1) proteins. Here we show that some Gram-positive bacterial species activate an immune response in a PGRP-SA- and GNBP1-independent manner, indicating that alternative receptors exist. Consistent with

Vincent Bischoff; Cécile Vignal; Ivo G Boneca; Tatiana Michel; Jules A Hoffmann; Julien Royet

2004-01-01

223

Molecular Characterization of the Acute Inflammatory Response to Infections with Gram-Negative versus Gram-Positive Bacteria  

Microsoft Academic Search

Sepsis caused by gram-negative bacteria and that caused by gram-positive bacteria often manifest similar clinical features. We investigated plasma proinflammatory cytokine profiles in patients with sepsis due to gram-positive and gram-negative bacteria and studied the cytokine production and differential gene regulation of leukocytes stimulated ex vivo with Escherichia coli lipopolysaccharide or heat-killed Staphylococcus aureus. Concentrations of tumor necrosis factor alpha,

Robert J. Feezor; Caroline Oberholzer; Henry V. Baker; Daniela Novick; Menachem Rubinstein; Lyle L. Moldawer; John Pribble; Sonia Souza; Charles A. Dinarello; Wolfgang Ertel; Andreas Oberholzer

2003-01-01

224

Sample preparation of Gram-positive bacteria for identification by matrix assisted laser desorption\\/ionization time-of-flight  

Microsoft Academic Search

A new sample preparation method was developed for fresh, whole-cell Gram-positive bacteria to be analyzed by matrix-assisted laser desorption\\/ionization time-of-flight mass spectrometry (MALDI ToF MS). With fresh, whole-cell Gram-negative bacteria of the Enterobacteriaceae family, we had previously achieved spectra consisting of >50 peaks and mass ranges of 2–25 kDa. Because similar spectral quantity could not be achieved for Gram-positive bacteria,

Sandra C Smole; Lisa A King; Peter E Leopold; Robert D Arbeit

2002-01-01

225

Cibacron blue 3GA inhibits cell separation of gram-positive bacteria  

Microsoft Academic Search

A triazine dye, Cibacron blue 3G-A (CB), is an inhibitor of cell separation of staphylococcal spp. therefore, we examined the effect of CB on growth of grampositive bacteria other than Staphylococcus. CB added to the medium of growing cultures of strains of genus Micrococcus, Streptococcus, Lactobacillus and Bacillus caused inhibition of cell separation. Moreover, in case of Bacillus and Lactobacillus,

Motoyuki Sugai; Tomoko Akiyama; Hitoshi Komatsuzawa; Yoichiro Miyake; Hidekazu Suginaka

1991-01-01

226

Genome Sequence of Bacillus subtilis subsp. spizizenii gtP20b, Isolated from the Indian Ocean ?  

PubMed Central

Bacillus subtilis is an aerobic spore-forming Gram-positive bacterium that is a model organism and of great industrial significance as the source of diverse novel functional molecules. Here we present, to our knowledge, the first genome sequence of Bacillus subtilis strain gtP20b isolated from the marine environment. A subset of candidate genes and gene clusters were identified, which are potentially involved in production of diverse functional molecules, like novel ribosomal and nonribosomal antimicrobial peptides. The genome sequence described in this paper is due to its high strain specificity of great importance for basic as well as applied researches on marine organisms.

Fan, Longjiang; Bo, Shiping; Chen, Huan; Ye, Wanzhi; Kleinschmidt, Katrin; Baumann, Heike I.; Imhoff, Johannes F.; Kleine, Michael; Cai, Daguang

2011-01-01

227

Comparative in vitro activity of gemifloxacin against gram-positive and gram-negative clinical isolates in Argentina.  

PubMed

The in vitro activity of gemifloxacin against 1,000 clinical isolates of 147 Streptococcus pneumoniae (115, penicilin susceptible; 26, intermediate penicillin-resistant and 6, penicillin-resistant), 127 Hemophilus influenzae (109, beta lactamasa non-producer; 18, beta lactamase producers), 95 Streptococcus pyogenes (6, azytromycin-resistant), 84 Moraxella catarrhalis (79, beta lactamase producers), 110 Staphilococcus aureus (89, methicillin-susceptible; 21, methicilin-resistant), 98 Eenterococcus faecalis and 339 Enterobacteriacea, (recovered from patients with respiratory tract infection; skin and soft tissue infection and urinary tract infection), was compared with the activities of four fluorquinolones and five other antimicrobial agents. Of the quinolones tested, gemifloxacin was the most potent against Streptococcus pneumoniae, including penicillin intermediate and resistant strains. Mic(90) values obtained for gemifloxacin, ciprofloxacin, ofloxacin, levofloxacin and trvafloxacin were 0.03, 2, 2, 1 and 0.25 mg/L respectively. Gemifloxacin was 16 fold more potent than ciprofloxacin against methicillin-susceptible Staphylococcus aureus and 32 fold more potent than ciprofloxacin against Streptococcus pyogenes. When tested against Hemophilus influenzae, Moraxella catarrhalis and Enterobacteriaceae, all the quinolones showed similar activity. Our results demonstrate that gemifloxacin has similar activity than the other quinolones tested against Gram-negative organisms and is considerably more potent against Gram-positive organisms. PMID:11576792

Lopez, H; Stepanik, D; Vilches, V; Scarano, S; Sarachian, B; Mikaelian, G; Finlay, J; Sucari, A

2001-08-01

228

Evaluation of the Merlin MICRONAUT System for Rapid Direct Susceptibility Testing of Gram-Positive Cocci and Gram-Negative Bacilli from Positive Blood Cultures?  

PubMed Central

Bloodstream infections are life-threatening conditions which require the timely initiation of appropriate antimicrobial therapy. We evaluated the automated Merlin MICRONAUT system for rapid direct microtiter broth antimicrobial susceptibility testing (AST) of gram-positive cocci and gram-negative bacilli from BACTEC 9240 bottles with positive blood cultures in comparison to the standard method for the Merlin MICRONAUT system. This prospective study was conducted under routine working conditions during a 9-month period. Altogether, 504 isolates from 409 patients and 11,819 organism-antibiotic combinations were evaluated for comparison of direct and standard AST methods. For gram-negative bacilli, direct and standard AST of 110 isolates was evaluated and MIC agreement was found for 98.1% of 2,637 organism-antibiotic combinations. Category (susceptible, intermediate susceptible, resistant [SIR]) agreement was found for 99.0%, with results for 0.04% of combinations showing very major errors, those for 0.2% showing major errors, and those for 0.8% showing minor errors. For gram-positive cocci, 373 isolates were evaluated and MIC agreement was found for 95.6% of 8,951 organism-antibiotic combinations. SIR agreement was found for 98.8%, with results for 0.3% of combinations showing very major errors, those for 0.4% showing major errors, and those for 0.5% showing minor errors. Although the number of tested isolates was limited (n = 33), direct AST of streptococci was performed for the first time, yielding promising results with SIR agreement for 98.6% of 363 organism-antibiotic combinations. In conclusion, direct AST of gram-negative bacilli and gram-positive cocci from positive blood cultures with the MICRONAUT system is a reliable technique that allows for the omission of repeat testing of subcultured isolates. Thereby, it reduces the time to results of blood culture testing and may have a positive impact on patient care.

Wellinghausen, Nele; Pietzcker, Tim; Poppert, Sven; Belak, Syron; Fieser, Nicole; Bartel, Melanie; Essig, Andreas

2007-01-01

229

Di-alkylated paromomycin derivatives: targeting the membranes of gram positive pathogens that cause skin infections.  

PubMed

A collection of paromomycin-based di-alkylated cationic amphiphiles differing in the lengths of their aliphatic chain residues were designed, synthesized, and evaluated against 14 Gram positive pathogens that are known to cause skin infections. Paromomycin derivatives that were di-alkylated with C7 and C8 linear aliphatic chains had improved antimicrobial activities relative to the parent aminoglycoside as well as to the clinically used membrane-targeting antibiotic gramicidin D; several novel derivatives were at least 16-fold more potent than the parent aminoglycoside paromomycin. Comparison between a di-alkylated and a mono-alkylated paromomycin indicated that the di-alkylation strategy leads to both an improvement in antimicrobial activity and to a dramatic reduction in undesired red blood cell hemolysis caused by many aminoglycoside-based cationic amphiphiles. Scanning electron microscopy provided evidence for cell surface damage by the reported di-alkylated paromomycins. PMID:23602621

Berkov-Zrihen, Yifat; Herzog, Ido M; Feldman, Mark; Sonn-Segev, Adar; Roichman, Yael; Fridman, Micha

2013-04-02

230

Sonodynamic Excitation of Rose Bengal for Eradication of Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Photodynamic antimicrobial chemotherapy based on photosensitizers activated by illumination is limited by poor penetration of visible light through skin and tissues. In order to overcome this problem, Rose Bengal was excited in the dark by 28?kHz ultrasound and was applied for inactivation of bacteria. It is demonstrated, for the first time, that the sonodynamic technique is effective for eradication of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The net sonodynamic effect was calculated as a 3-4 log10 reduction in bacteria concentration, depending on the cell and the Rose Bengal concentration and the treatment time. Sonodynamic treatment may become a novel and effective form of antimicrobial therapy and can be used for low-temperature sterilization of medical instruments and surgical accessories.

Nakonechny, Faina; Nisnevitch, Michael; Nitzan, Yeshayahu; Nisnevitch, Marina

2013-01-01

231

Discovery of selective and potent inhibitors of gram-positive bacterial thymidylate kinase (TMK).  

PubMed

Thymidylate kinase (TMK) is an essential enzyme in bacterial DNA synthesis. The deoxythymidine monophosphate (dTMP) substrate binding pocket was targeted in a rational-design, structure-supported effort, yielding a unique series of antibacterial agents showing a novel, induced-fit binding mode. Lead optimization, aided by X-ray crystallography, led to picomolar inhibitors of both Streptococcus pneumoniae and Staphylococcus aureus TMK. MICs < 1 ?g/mL were achieved against methicillin-resistant S. aureus (MRSA), S. pneumoniae, and vancomycin-resistant Enterococcus (VRE). Log D adjustments yielded single diastereomers 14 (TK-666) and 46, showing a broad antibacterial spectrum against Gram-positive bacteria and excellent selectivity against the human thymidylate kinase ortholog. PMID:23043329

Martínez-Botella, Gabriel; Breen, John N; Duffy, James E S; Dumas, Jacques; Geng, Bolin; Gowers, Ian K; Green, Oluyinka M; Guler, Satenig; Hentemann, Martin F; Hernandez-Juan, Felix A; Joseph-McCarthy, Diane; Kawatkar, Sameer; Larsen, Nicholas A; Lazari, Ovadia; Loch, James T; Macritchie, Jacqueline A; McKenzie, Andrew R; Newman, Joseph V; Olivier, Nelson B; Otterson, Linda G; Owens, Andrew P; Read, Jon; Sheppard, David W; Keating, Thomas A

2012-10-24

232

Innate inflammatory responses to the Gram-positive bacterium Lactococcus lactis.  

PubMed

Lactococcus lactis is a non-pathogenic and non-colonizing Gram-positive bacterium commonly used in the dairy industry. To support the potential applications of this bacterium, such as use as an oral live vaccine, it is of interest to investigate the adjuvant properties of L. lactis. We compared the proinflammatory effects of L. lactis with two non-pathogenic Gram-negative bacteria: Escherichia coli and Salmonella typhi, a widely studied live vaccine. The gene expression profiles of chemokines induced by the three bacteria were examined in macrophages in vitro and in cells recruited into murine air-pouches in vivo. In addition, we studied the effect of co-incubating bacteria with dendritic cells (DCs) generated from mice bone marrow. We demonstrate that L. lactis exhibits proinflammatory effects, which indicates a capacity for adjuvanticity by this bacterium. PMID:18436352

Yam, Karen K; Pouliot, Philippe; N'diaye, Marie M; Fournier, Sylvie; Olivier, Martin; Cousineau, Benoit

2008-04-03

233

Bacteriophage endolysins: A novel anti-infective to control Gram-positive pathogens  

PubMed Central

Endolysins (or lysins) are highly evolved enzymes produced by bacteriophage (phage for short) to digest the bacterial cell wall for phage progeny release. In Gram-positive bacteria, small quantities of purified recombinant lysin added externally results in immediate lysis causing log-fold death of the target bacterium. Lysins have been used successfully in a variety of animal models to control pathogenic antibiotic-resistant bacteria found on mucosal surfaces and infected tissues. Their specificity for the pathogen without disturbing the normal flora, the low chance of bacterial resistance, and their ability to kill colonizing pathogens on mucosal surfaces, a capacity previously unavailable, make them ideal anti-infectives in an age of mounting resistance. Here we review the current literature showing the effectiveness of these enzymes in controlling a variety of infections.

Fischetti, Vincent A.

2010-01-01

234

Raman Spectroscopy of Xylitol Uptake and Metabolism in Gram-Positive and Gram-Negative Bacteria?  

PubMed Central

Visible-wavelength Raman spectroscopy was used to investigate the uptake and metabolism of the five-carbon sugar alcohol xylitol by Gram-positive viridans group streptococcus and the two extensively used strains of Gram-negative Escherichia coli, E. coli C and E. coli K-12. E. coli C, but not E. coli K-12, contains a complete xylitol operon, and the viridans group streptococcus contains an incomplete xylitol operon used to metabolize the xylitol. Raman spectra from xylitol-exposed viridans group streptococcus exhibited significant changes that persisted even in progeny grown from the xylitol-exposed mother cells in a xylitol-free medium for 24 h. This behavior was not observed in the E. coli K-12. In both viridans group streptococcus and the E. coli C derivative HF4714, the metabolic intermediates are stably formed to create an anomaly in bacterial normal survival. The uptake of xylitol by Gram-positive and Gram-negative pathogens occurs even in the presence of other high-calorie sugars, and its stable integration within the bacterial cell wall may discontinue bacterial multiplication. This could be a contributing factor for the known efficacy of xylitol when taken as a prophylactic measure to prevent or reduce occurrences of persistent infection. Specifically, these bacteria are causative agents for several important diseases of children such as pneumonia, otitis media, meningitis, and dental caries. If properly explored, such an inexpensive and harmless sugar-alcohol, alone or used in conjunction with fluoride, would pave the way to an alternative preventive therapy for these childhood diseases when the causative pathogens have become resistant to modern medicines such as antibiotics and vaccine immunotherapy.

Palchaudhuri, Sunil; Rehse, Steven J.; Hamasha, Khozima; Syed, Talha; Kurtovic, Eldar; Kurtovic, Emir; Stenger, James

2011-01-01

235

In vitro and in vivo antibacterial activities of heteroaryl isothiazolones against resistant gram-positive pathogens.  

PubMed

The activities of several tricyclic heteroaryl isothiazolones (HITZs) against an assortment of gram-positive and gram-negative clinical isolates were assessed. These compounds target bacterial DNA replication and were found to possess broad-spectrum activities especially against gram-positive strains, including antibiotic-resistant staphylococci and streptococci. These included methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-nonsusceptible staphylococci, and quinolone-resistant strains. The HITZs were more active than the comparator antimicrobials in most cases. For gram-negative bacteria, the tested compounds were less active against members of the family Enterobacteriaceae but showed exceptional potencies against Haemophilus influenzae, Moraxella catarrhalis, and Neisseria spp. Good activity against several anaerobes, as well as Legionella pneumophila and Mycoplasma pneumoniae, was also observed. Excellent bactericidal activity against staphylococci was observed in time-kill assays, with an approximately 3-log drop in the numbers of CFU/ml occurring after 4 h of exposure to compound. Postantibiotic effects (PAEs) of 2.0 and 1.7 h for methicillin-susceptible S. aureus and MRSA strains, respectively, were observed, and these were similar to those seen with moxifloxacin at 10x MIC. In vivo efficacy was demonstrated in murine infections by using sepsis and thigh infection models. The 50% protective doses were

Pucci, Michael J; Cheng, Jijun; Podos, Steven D; Thoma, Christy L; Thanassi, Jane A; Buechter, Douglas D; Mushtaq, Gohar; Vigliotti, Gerald A; Bradbury, Barton J; Deshpande, Milind

2007-01-22

236

In Vitro and In Vivo Antibacterial Activities of Heteroaryl Isothiazolones against Resistant Gram-Positive Pathogens?  

PubMed Central

The activities of several tricyclic heteroaryl isothiazolones (HITZs) against an assortment of gram-positive and gram-negative clinical isolates were assessed. These compounds target bacterial DNA replication and were found to possess broad-spectrum activities especially against gram-positive strains, including antibiotic-resistant staphylococci and streptococci. These included methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-nonsusceptible staphylococci, and quinolone-resistant strains. The HITZs were more active than the comparator antimicrobials in most cases. For gram-negative bacteria, the tested compounds were less active against members of the family Enterobacteriaceae but showed exceptional potencies against Haemophilus influenzae, Moraxella catarrhalis, and Neisseria spp. Good activity against several anaerobes, as well as Legionella pneumophila and Mycoplasma pneumoniae, was also observed. Excellent bactericidal activity against staphylococci was observed in time-kill assays, with an approximately 3-log drop in the numbers of CFU/ml occurring after 4 h of exposure to compound. Postantibiotic effects (PAEs) of 2.0 and 1.7 h for methicillin-susceptible S. aureus and MRSA strains, respectively, were observed, and these were similar to those seen with moxifloxacin at 10× MIC. In vivo efficacy was demonstrated in murine infections by using sepsis and thigh infection models. The 50% protective doses were ?1 mg/kg of body weight against S. aureus in the sepsis model, while decreases in the numbers of CFU per thigh equal to or greater than those detected in animals treated with a standard dose of vancomycin were seen in the animals with thigh infections. Pharmacokinetic analyses of treated mice indicated exposures similar to those to ciprofloxacin at equivalent dose levels. These promising initial data suggest further study on the use of the HITZs as antibacterial agents.

Pucci, Michael J.; Cheng, Jijun; Podos, Steven D.; Thoma, Christy L.; Thanassi, Jane A.; Buechter, Douglas D.; Mushtaq, Gohar; Vigliotti, Gerald A.; Bradbury, Barton J.; Deshpande, Milind

2007-01-01

237

In vitro and in vivo activities of a new quinolone, WIN 57273, possessing potent activity against gram-positive bacteria.  

PubMed Central

The antibacterial activity of a new 7-dimethylpyridinyl quinolone, WIN 57273, was assessed by using in vitro and in vivo models. Agar inclusion and broth dilution in vitro tests revealed broad-spectrum activity against gram-positive and selected gram-negative organisms, with the greatest potency observed against the staphylococci. The MIC for 90% of coagulase-positive strains tested (MIC90) was less than or equal to 0.002 micrograms/ml; for the coagulase-negative strains the MIC90 was 0.008 micrograms/ml. Against enterococci the MIC90 was 0.06 micrograms/ml, with comparable activity observed against group A and group B streptococci as well as against the pneumococci. In general, the MIC90s for the gram-negative bacteria were less than or equal to 1 micrograms/ml. Exceptions were Serratia marcescens (MIC90, 16 micrograms/ml), Citrobacter freundii (MIC90, 4 micrograms/ml), and Pseudomonas aeruginosa (MIC90, 8 micrograms/ml). The greatest potency was observed against Haemophilus spp. and Neisseria spp., with MIC90s of 0.06 and 0.016 micrograms/ml, respectively. Broad-spectrum activity was also observed against anaerobes, with MIC90s ranging from 0.125 to 0.5 micrograms/ml among the species tested. The in vivo efficacy was determined by using a murine model by calculating the 50% protective doses against a lethal bacterial infection caused by strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Listeria monocytogenes, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The staphylocci were most susceptible, with 50% protective doses for all strains ranging from 0.1 to 0.7 mg/kg. With the exception of the Pseudomonas infection, which was refractory to treatment, animals that were part of the other infection models responded to less than 10 mg/kg. Equivalent activity was seen with the subcutaneous or the oral route of drug administration. WIN 57273 was significantly more potent than ciprofloxacin in treating gram-positive bacterial infections (2- to 20-fold) but was significantly less effective at treating gram-negative bacterial infections (30- to 300-fold).

Sedlock, D M; Dobson, R A; Deuel, D M; Lesher, G Y; Rake, J B

1990-01-01

238

In vitro and in vivo activities of a new quinolone, WIN 57273, possessing potent activity against gram-positive bacteria.  

PubMed

The antibacterial activity of a new 7-dimethylpyridinyl quinolone, WIN 57273, was assessed by using in vitro and in vivo models. Agar inclusion and broth dilution in vitro tests revealed broad-spectrum activity against gram-positive and selected gram-negative organisms, with the greatest potency observed against the staphylococci. The MIC for 90% of coagulase-positive strains tested (MIC90) was less than or equal to 0.002 micrograms/ml; for the coagulase-negative strains the MIC90 was 0.008 micrograms/ml. Against enterococci the MIC90 was 0.06 micrograms/ml, with comparable activity observed against group A and group B streptococci as well as against the pneumococci. In general, the MIC90s for the gram-negative bacteria were less than or equal to 1 micrograms/ml. Exceptions were Serratia marcescens (MIC90, 16 micrograms/ml), Citrobacter freundii (MIC90, 4 micrograms/ml), and Pseudomonas aeruginosa (MIC90, 8 micrograms/ml). The greatest potency was observed against Haemophilus spp. and Neisseria spp., with MIC90s of 0.06 and 0.016 micrograms/ml, respectively. Broad-spectrum activity was also observed against anaerobes, with MIC90s ranging from 0.125 to 0.5 micrograms/ml among the species tested. The in vivo efficacy was determined by using a murine model by calculating the 50% protective doses against a lethal bacterial infection caused by strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Streptococcus pyogenes, Listeria monocytogenes, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The staphylocci were most susceptible, with 50% protective doses for all strains ranging from 0.1 to 0.7 mg/kg. With the exception of the Pseudomonas infection, which was refractory to treatment, animals that were part of the other infection models responded to less than 10 mg/kg. Equivalent activity was seen with the subcutaneous or the oral route of drug administration. WIN 57273 was significantly more potent than ciprofloxacin in treating gram-positive bacterial infections (2- to 20-fold) but was significantly less effective at treating gram-negative bacterial infections (30- to 300-fold). PMID:2344163

Sedlock, D M; Dobson, R A; Deuel, D M; Lesher, G Y; Rake, J B

1990-04-01

239

Thinking About Bacillus subtilis as a Multicellular Organism  

PubMed Central

Summary Initial attempts to use colony morphogenesis as a tool to investigate bacterial multicellularity were limited by the fact that laboratory strains often have lost many of their developmental properties. Recent advances in elucidating the molecular mechanisms underlying colony morphogenesis have been made possible through the use of undomesticated strains. In particular, Bacillus subtilis has proven to be a remarkable model system to study colony morphogenesis because of it well-characterized developmental features. Genetic screens that analyze mutants defective in colony morphology have led to the discovery of an intricate regulatory network that controls the production of an extracellular matrix. This matrix is essential for the development of complex colony architecture characterized by aerial projections that serve as preferential sites for sporulation. While much progress has been made, the challenge for future studies will be to determine the underlying mechanisms that regulate development such that differentiation occurs in a spatially and temporally organized manner.

Aguilar, Claudio; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

2007-01-01

240

Identification and characterization of a new xylanase from Gram-positive bacteria isolated from termite gut (Reticulitermes santonensis).  

PubMed

Termites are world champions at digesting lignocellulosic compounds, thanks to cooperation between their own enzymes and exogenous enzymes from microorganisms. Prokaryotic cells are responsible for a large part of this lignocellulolytic activity. Bacterial enzyme activities have been demonstrated in the higher and the lower termite gut. From five clones of Gram-positive bacteria isolated and identified in a previous work, we constructed a genomic DNA library and performed functional screening for alpha-amylase, beta-glucosidase, and xylanase activities. One candidate, Xyl8B8, showed xylanase activity. Sequence analysis of the genomic insert revealed five complete ORFs on the cloned DNA (5746bp). Among the encoded proteins were a putative endo-1,4-beta-xylanase (XylB8) belonging to glycoside hydrolase family 11 (GH11). On the basis of sequence analyses, genomic DNA organization, and phylogenetic analysis, the insert was shown to come from an actinobacterium. The mature xylanase (mXylB8) was expressed in Escherichia coli and purified by affinity chromatography and detected by zymogram analysis after renaturing. It showed maximal xylanase activity in sodium acetate buffer, pH 5.0 at 55 °C. Its activity was increased by reducing agents and decreased by Cu(2+), some detergents, and chelating agents. Its substrate specificity appeared limited to xylan. PMID:22487213

Mattéotti, Christel; Bauwens, Julien; Brasseur, Catherine; Tarayre, Cédric; Thonart, Philippe; Destain, Jacqueline; Francis, Frédéric; Haubruge, Eric; De Pauw, Edwin; Portetelle, Daniel; Vandenbol, Micheline

2012-04-02

241

DNA Repair and Genome Maintenance in Bacillus subtilis  

PubMed Central

Summary: From microbes to multicellular eukaryotic organisms, all cells contain pathways responsible for genome maintenance. DNA replication allows for the faithful duplication of the genome, whereas DNA repair pathways preserve DNA integrity in response to damage originating from endogenous and exogenous sources. The basic pathways important for DNA replication and repair are often conserved throughout biology. In bacteria, high-fidelity repair is balanced with low-fidelity repair and mutagenesis. Such a balance is important for maintaining viability while providing an opportunity for the advantageous selection of mutations when faced with a changing environment. Over the last decade, studies of DNA repair pathways in bacteria have demonstrated considerable differences between Gram-positive and Gram-negative organisms. Here we review and discuss the DNA repair, genome maintenance, and DNA damage checkpoint pathways of the Gram-positive bacterium Bacillus subtilis. We present their molecular mechanisms and compare the functions and regulation of several pathways with known information on other organisms. We also discuss DNA repair during different growth phases and the developmental program of sporulation. In summary, we present a review of the function, regulation, and molecular mechanisms of DNA repair and mutagenesis in Gram-positive bacteria, with a strong emphasis on B. subtilis.

Lenhart, Justin S.; Schroeder, Jeremy W.; Walsh, Brian W.

2012-01-01

242

Role of Superoxide in the Germination of Bacillus Anthracis Endospores.  

National Technical Information Service (NTIS)

The spore forming Gram-positive bacterium Bacillus anthracis, the causative agent of anthrax, has achieved notoriety due to its use as a bioterror agent. In the environment, B. anthracis exists as a dormant endospore. Germination of endospores during thei...

G. Cao G. M. Rosen L. Baillie P. Tsai S. Hibbs

2005-01-01

243

Isolation and characterization of four novel Gram-positive bacteria associated with the rhizosphere of two endemorelict plants capable of degrading a broad range of aromatic substrates.  

PubMed

Four new Gram-positive, phenol-degrading strains were isolated from the rhizospheres of endemorelict plants Ramonda serbica and Ramonda nathaliae known to exude high amounts of phenolics in the soil. Isolates were designated Bacillus sp. PS1, Bacillus sp. PS11, Streptomyces sp. PS12, and Streptomyces sp. PN1 based on 16S rDNA sequence and biochemical analysis. In addition to their ability to tolerate and utilize high amounts of phenol of either up to 800 or up to 1,400 mg l(-1) without apparent inhibition in growth, all four strains were also able to degrade a broad range of aromatic substrates including benzene, toluene, ethylbenzene, xylenes, styrene, halogenated benzenes, and naphthalene. Isolates were able to grow in pure culture and in defined mixed culture on phenol and on the mixture of BTEX (benzene, toluene, ethylbenzene, and xylenes) compounds as a sole source of carbon and energy. Pure culture of Bacillus sp. PS11 yielded 1.5-fold higher biomass amounts in comparison to mixed culture, under all conditions. Strains successfully degraded phenol in the soil model system (2 g kg(-1)) within 6 days. Activities of phenol hydroxylase, catechol 1,2-dioxygenase, and catechol 2,3-dioxygenase were detected and analyzed from the crude cell extract of the isolates. While all four strains use ortho degradation pathway, enzyme indicative of meta degradation pathway (catechol 2,3-dioxygenase) was also detected in Bacillus sp. PS11 and Streptomyces sp. PN1. Phenol degradation activities were induced 2 h after supplementation by phenol, but not by catechol. Catechol slightly inhibited activity of catechol 2,3-dioxygenase in strains PS11 and PN1. PMID:21706169

Djokic, Lidija; Narancic, Tanja; Nikodinovic-Runic, Jasmina; Savic, Miloje; Vasiljevic, Branka

2011-06-25

244

A functional interaction between the putative primosomal protein DnaI and the main replicative DNA helicase DnaB in Bacillus  

Microsoft Academic Search

In Gram negative Escherichia coli there are two well- characterised primosomal assembly processes, the PriA- and DnaA-mediated cascades. The presence of PriA and DnaA proteins in Gram positive Bacillus spp. supports the assumption that both the PriA- and DnaA-mediated primosomal assembly cascades also operate in these organisms. However, the lack of sequence homology between the rest of the primo- somal

P. Soultanas

2002-01-01

245

Homologs of the Rml Enzymes from Salmonella enterica Are Responsible for dTDP-?-l-Rhamnose Biosynthesis in the Gram-Positive Thermophile Aneurinibacillus thermoaerophilus DSM 10155  

PubMed Central

The glycan chains of the surface layer (S-layer) glycoprotein from the gram-positive, thermophilic bacterium Aneurinibacillus (formerly Bacillus) thermoaerophilus strain DSM 10155 are composed of l-rhamnose- and d-glycero-d-manno-heptose-containing disaccharide repeating units which are linked to the S-layer polypeptide via core structures that have variable lengths and novel O-glycosidic linkages. In this work we investigated the enzymes involved in the biosynthesis of thymidine diphospho-l-rhamnose (dTDP-l-rhamnose) and their specific properties. Comparable to lipopolysaccharide O-antigen biosynthesis in gram-negative bacteria, dTDP-l-rhamnose is synthesized in a four-step reaction sequence from dTTP and glucose 1-phosphate by the enzymes glucose-1-phosphate thymidylyltransferase (RmlA), dTDP-d-glucose 4,6-dehydratase (RmlB), dTDP-4-dehydrorhamnose 3,5-epimerase (RmlC), and dTDP-4-dehydrorhamnose reductase (RmlD). The rhamnose biosynthesis operon from A. thermoaerophilus DSM 10155 was sequenced, and the genes were overexpressed in Escherichia coli. Compared to purified enterobacterial Rml enzymes, the enzymes from the gram-positive strain show remarkably increased thermostability, a property which is particularly interesting for high-throughput screening and enzymatic synthesis. The closely related strain A. thermoaerophilus L420-91T produces d-rhamnose- and 3-acetamido-3,6-dideoxy-d-galactose-containing S-layer glycan chains. Comparison of the enzyme activity patterns in A. thermoaerophilus strains DSM 10155 and L420-91T for l-rhamnose and d-rhamnose biosynthesis indicated that the enzymes are differentially expressed during S-layer glycan biosynthesis and that A. thermoaerophilus L420-91T is not able to synthesize dTDP-l-rhamnose. These findings confirm that in each strain the enzymes act specifically on S-layer glycoprotein glycan formation.

Graninger, Michael; Kneidinger, Bernd; Bruno, Katharina; Scheberl, Andrea; Messner, Paul

2002-01-01

246

Global mRNA decay analysis at single nucleotide resolution reveals segmental and positional degradation patterns in a Gram-positive bacterium  

PubMed Central

Background Recent years have shown a marked increase in the use of next-generation sequencing technologies for quantification of gene expression (RNA sequencing, RNA-Seq). The expression level of a gene is a function of both its rate of transcription and RNA decay, and the influence of mRNA decay rates on gene expression in genome-wide studies of Gram-positive bacteria is under-investigated. Results In this work, we employed RNA-Seq in a genome-wide determination of mRNA half-lives in the Gram-positive bacterium Bacillus cereus. By utilizing a newly developed normalization protocol, RNA-Seq was used successfully to determine global mRNA decay rates at the single nucleotide level. The analysis revealed positional degradation patterns, with mRNAs being degraded from both ends of the molecule, indicating that both 5' to 3' and 3' to 5' directions of RNA decay are present in B. cereus. Other operons showed segmental degradation patterns where specific ORFs within polycistrons were degraded at variable rates, underlining the importance of RNA processing in gene regulation. We determined the half-lives for more than 2,700 ORFs in B. cereus ATCC 10987, ranging from less than one minute to more than fifteen minutes, and showed that mRNA decay rate correlates globally with mRNA expression level, GC content, and functional class of the ORF. Conclusions To our knowledge, this study presents the first global analysis of mRNA decay in a bacterium at single nucleotide resolution. We provide a proof of principle for using RNA-Seq in bacterial mRNA decay analysis, revealing RNA processing patterns at the single nucleotide level.

2012-01-01

247

Isomerization of an Antimicrobial Peptide Broadens Antimicrobial Spectrum to Gram-Positive Bacterial Pathogens  

PubMed Central

The branched M33 antimicrobial peptide was previously shown to be very active against Gram-negative bacterial pathogens, including multidrug-resistant strains. In an attempt to produce back-up molecules, we synthesized an M33 peptide isomer consisting of D-aminoacids (M33-D). This isomeric version showed 4 to 16-fold higher activity against Gram-positive pathogens, including Staphylococcus aureus and Staphylococcus epidermidis, than the original peptide, while retaining strong activity against Gram-negative bacteria. The antimicrobial activity of both peptides was influenced by their differential sensitivity to bacterial proteases. The better activity shown by M33-D against S. aureus compared to M33-L was confirmed in biofilm eradication experiments where M33-L showed 12% activity with respect to M33-D, and in vivo models where Balb-c mice infected with S. aureus showed 100% and 0% survival when treated with M33-D and M33-L, respectively. M33-D appears to be an interesting candidate for the development of novel broad-spectrum antimicrobials active against bacterial pathogens of clinical importance.

Pollini, Simona; Luca, Vincenzo; Carnicelli, Veronica; Brunetti, Jlenia; Lelli, Barbara; Bindi, Stefano; Scali, Silvia; Di Giulio, Antonio; Rossolini, Gian Maria; Mangoni, Maria Luisa; Bracci, Luisa; Pini, Alessandro

2012-01-01

248

Revised mechanism of d-alanine incorporation into cell wall polymers in Gram-positive bacteria  

PubMed Central

Teichoic acids (TAs) are important for growth, biofilm formation, adhesion and virulence of Gram-positive bacterial pathogens. The chemical structures of the TAs vary between bacteria, though they typically consist of zwitterionic polymers that are anchored to either the peptidoglycan layer as in the case of wall teichoic acid (WTA) or the cell membrane and named lipoteichoic acid (LTA). The polymers are modified with d-alanines and a lack of this decoration leads to increased susceptibility to cationic antimicrobial peptides. Four proteins, DltA–D, are essential for the incorporation of d-alanines into cell wall polymers and it has been established that DltA transfers d-alanines in the cytoplasm of the cell onto the carrier protein DltC. However, two conflicting models have been proposed for the remainder of the mechanism. Using a cellular protein localization and membrane topology analysis, we show here that DltC does not traverse the membrane and that DltD is anchored to the outside of the cell. These data are in agreement with the originally proposed model for d-alanine incorporation through a process that has been proposed to proceed via a d-alanine undecaprenyl phosphate membrane intermediate. Furthermore, we found that WTA isolated from a Staphylococcus aureus strain lacking LTA contains only a small amount of d-alanine, indicating that LTA has a role, either direct or indirect, in the efficient d-alanine incorporation into WTA in living cells.

Reichmann, Nathalie T.; Cassona, Carolina Picarra

2013-01-01

249

Exploiting what phage have evolved to control gram-positive pathogens  

PubMed Central

In the billion years that bacteriophage (or phage) have existed together with bacteria the phage have evolved systems that may be exploited for our benefit. One of these is the lytic system used by the phage to release their progeny from an infected bacterium. Endolysins (or lysins) are highly evolved enzymes in the lytic system produced to cleave essential bonds in the bacterial cell wall peptidoglycan for progeny release. Small quantities of purified recombinant lysin added externally to gram-positive bacteria results in immediate lysis causing log-fold death of the target bacterium. Lysins have now been used successfully in a variety of animal models to control pathogenic antibiotic resistant bacteria found on mucosal surfaces and in infected tissues. The advantages over antibiotics are their specificity for the pathogen without disturbing the normal flora, the low chance of bacterial resistance, and their ability to kill colonizing pathogens on mucosal surfaces, a capacity previously unavailable. Lysins therefore, may be a much-needed anti-infective (or enzybiotic) in an age of mounting antibiotic resistance.

Fischetti, Vincent A.

2011-01-01

250

Gram-positive pathogenic bacteria induce a common early response in human monocytes  

PubMed Central

Background We infected freshly isolated human peripheral monocytes with live bacteria of three clinically important gram-positive bacterial species, Staphylococcus aureus, Streptococcus pneumoniae and Listeria monocytogenes and studied the ensuing early transcriptional response using expression microarrays. Thus the observed response was unbiased by signals originating from other helper and effector cells of the host and was not limited to induction by solitary bacterial constituents. Results Activation of monocytes was demonstrated by the upregulation of chemokine rather than interleukin genes except for the prominent expression of interleukin 23, marking it as the early lead cytokine. This activation was accompanied by cytoskeleton rearrangement signals and a general anti-oxidative stress and anti-apoptotic reaction. Remarkably, the expression profiles also provide evidence that monocytes participate in the regulation of angiogenesis and endothelial function in response to these pathogens. Conclusion Regardless of the invasion properties and survival mechanisms of the pathogens used, we found that the early response comprised of a consistent and common response. The common response was hallmarked by the upregulation of interleukin 23, a rather unexpected finding regarding Listeria infection, as this cytokine has been linked primarily to the control of extracellular bacterial dissemination.

2010-01-01

251

A role for glycosylated Serine-rich repeatproteins in Gram-positive bacterial pathogenesis  

PubMed Central

Summary Bacterial attachment to host surfaces is a pivotal event in the biological and infectious processes of both commensal and pathogenic bacteria, respectively. Serine-rich Repeat Proteins (SRRPs) are a family of adhesins in Gram-Positive bacteria that mediate attachment to a variety of host and bacterial surfaces. As such, they contribute towards a wide-range of diseases including sub-acute bacterial endocarditis, community-acquired pneumonia, and meningitis. SRRPs are unique in that they are glycosylated, require a non-canonical Sec-translocase for transport, and are largely composed of a domain containing hundreds of alternating serine residues. These serine-rich repeats are thought to extend a unique non-repeat (NR) domain outward away from the bacterial surface to mediate adhesion. Thus far, NR domains have been determined to bind to sialic acid moieties, keratins, or other NR domains of a similar SRRP. This review summarizes how this important family of bacterial adhesins mediates bacterial attachment to host and bacterial cells, contributes to disease pathogenesis, and might be targeted for pharmacological intervention or used as novel protective vaccine antigens. This review also highlights recent structural findings on the NR domains of these proteins.

Lizcano, Anel; Sanchez, Carlos J.; Orihuela, Carlos J.

2012-01-01

252

Gene targeting in the Gram-Positive bacterium Lactococcus lactis, using various delta ribozymes.  

PubMed

The trans-acting antigenomic delta ribozyme, isolated from the human hepatitis delta virus, was shown to be highly stable and active in vitro, as well as in mammalian cell lines. However, the stability and gene-targeting competence of this small ribozyme have not been studied previously in bacterial cells. In this paper we describe the use of two variants of the trans-acting antigenomic delta ribozyme targeting the abundant EF-Tu mRNA in the industrially important gram-positive bacterium Lactococcus lactis. These two delta ribozyme variants were expressed at significant levels and were shown to be highly stable in vivo. The half-life of the EF-Tu mRNA was slightly but consistently reduced in the presence of the classical delta ribozymes (7 to 13%). In contrast, delta ribozymes harboring a specific on/off riboswitch (SOFA-delta ribozymes) targeting the same sites on the EF-Tu mRNA considerably reduced the half-life of this mRNA (22 to 47%). The rates of catalysis of the SOFA-delta ribozymes in L. lactis were similar to the rates determined in vitro, showing that this new generation of delta ribozymes was highly efficient in these bacterial cells. Clearly, SOFA-delta ribozymes appear to be an ideal means for development of gene inactivation systems in bacteria. PMID:16391129

Fiola, Karine; Perreault, Jean-Pierre; Cousineau, Benoit

2006-01-01

253

Inactivation of Gram-positive biofilms by low-temperature plasma jet at atmospheric pressure  

NASA Astrophysics Data System (ADS)

This work is devoted to the evaluation of the efficiency of a new low-temperature plasma jet driven in ambient air by a dc-corona discharge to inactivate adherent cells and biofilms of Gram-positive bacteria. The selected microorganisms were lactic acid bacteria, a Weissella confusa strain which has the particularity to excrete a polysaccharide polymer (dextran) when sucrose is present. Both adherent cells and biofilms were treated with the low-temperature plasma jet for different exposure times. The antimicrobial efficiency of the plasma was tested against adherent cells and 48 h-old biofilms grown with or without sucrose. Bacterial survival was estimated using both colony-forming unit counts and fluorescence-based assays for bacterial cell viability. The experiments show the ability of the low-temperature plasma jet at atmospheric pressure to inactivate the bacteria. An increased resistance of bacteria embedded within biofilms is clearly observed. The resistance is also significantly higher with biofilm in the presence of sucrose, which indicates that dextran could play a protective role.

Marchal, F.; Robert, H.; Merbahi, N.; Fontagné-Faucher, C.; Yousfi, M.; Romain, C. E.; Eichwald, O.; Rondel, C.; Gabriel, B.

2012-08-01

254

Sortases and the Art of Anchoring Proteins to the Envelopes of Gram-Positive Bacteria  

PubMed Central

The cell wall envelopes of gram-positive bacteria represent a surface organelle that not only functions as a cytoskeletal element but also promotes interactions between bacteria and their environment. Cell wall peptidoglycan is covalently and noncovalently decorated with teichoic acids, polysaccharides, and proteins. The sum of these molecular decorations provides bacterial envelopes with species- and strain-specific properties that are ultimately responsible for bacterial virulence, interactions with host immune systems, and the development of disease symptoms or successful outcomes of infections. Surface proteins typically carry two topogenic sequences, i.e., N-terminal signal peptides and C-terminal sorting signals. Sortases catalyze a transpeptidation reaction by first cleaving a surface protein substrate at the cell wall sorting signal. The resulting acyl enzyme intermediates between sortases and their substrates are then resolved by the nucleophilic attack of amino groups, typically provided by the cell wall cross bridges of peptidoglycan precursors. The surface protein linked to peptidoglycan is then incorporated into the envelope and displayed on the microbial surface. This review focuses on the mechanisms of surface protein anchoring to the cell wall envelope by sortases and the role that these enzymes play in bacterial physiology and pathogenesis.

Marraffini, Luciano A.; DeDent, Andrea C.; Schneewind, Olaf

2006-01-01

255

Can procalcitonin differentiate Staphylococcus aureus from coagulase-negative staphylococci in clustered gram-positive bacteremia?  

PubMed

Procalcitonin (PCT) and pro-adrenomedullin (ProADM) have been proposed as diagnostic and prognostic biomarkers of infection. Between July 2009 and January 2012, we studied the role of these biomarkers in 163 patients with clustered gram-positive and gram-negative bacteremia. PCT levels were significantly higher in patients with Staphylococcus aureus and gram-negative bacteremia than those with coagulase-negative staphylococci (CoNS) isolated from blood cultures (P = 0.29 and <0.001, respectively). ProADM levels were only significantly higher in patients with gram-negative bacteremia (median 1.46 nmol/L) than those with CoNS (median 1.01 nmol/L) (P = 0.04). Among patients with CoNS, PCT, and ProADM, levels failed to differentiate blood contamination (medians 0.24 ng/mL and 0.97 nmol/L) from true bacteremia (medians 0.26 ng/mL and 1.14 nmol/L) (P = 0.51 and 0.57, respectively). In cancer patients, PCT (and to a lesser extent, ProADM) was useful in differentiating CoNS from S. aureus and gram-negative bacteremia. PMID:23578976

Shomali, William; Hachem, Ray; Chaftari, Anne-Marie; Bahu, Ramez; Helou, Gilbert El; Jiang, Ying; Hanania, Alex; Reitzel, Ruth; Raad, Issam

2013-04-08

256

Surface display of a single-domain antibody library on Gram-positive bacteria.  

PubMed

Combinatorial protein engineering for selection of proteins with novel functions, such as enzymes and affinity reagents, is an important tool in biotechnology, drug discovery, and other biochemical fields. Bacterial display is an emerging technology for isolation of new affinity proteins from such combinatorial libraries. Cells have certain properties that are attractive for directed evolution purposes, in particular the option to use quantitative flow-cytometric cell sorting for selection of binders. Here, an immune library of around 10(7) camelid single-domain antibody fragments (Nanobodies) was displayed on both the Gram-positive bacterium Staphylococcus carnosus and on phage. As demonstrated for the first time, the antibody repertoire was found to be well expressed on the bacterial surface and flow-cytometric sorting yielded a number of Nanobodies with subnanomolar affinity for the target protein, green fluorescent protein (GFP). Interestingly, the staphylococcal output repertoire and the binders from the phage display selection contained two slightly different sets of clones, containing both unique as well as several similar variants. All of the Nanobodies from the staphylococcal selection were also shown to enhance the fluorescence of GFP upon binding, potentially due to the fluorescence-based sorting principle. Our study highlights the impact of the chosen display technology on the variety of selected binders and thus the value of having alternative methods available, and demonstrates in addition that the staphylococcal system is suitable for generation of high-affinity antibody fragments. PMID:23064703

Fleetwood, Filippa; Devoogdt, Nick; Pellis, Mireille; Wernery, Ulrich; Muyldermans, Serge; Ståhl, Stefan; Löfblom, John

2012-10-13

257

Genome sequence of Desulfitobacterium hafniense DCB-2, a Gram-positive anaerobe capable of dehalogenation and metal reduction  

PubMed Central

Background The genome of the Gram-positive, metal-reducing, dehalorespiring Desulfitobacterium hafniense DCB-2 was sequenced in order to gain insights into its metabolic capacities, adaptive physiology, and regulatory machineries, and to compare with that of Desulfitobacterium hafniense Y51, the phylogenetically closest strain among the species with a sequenced genome. Results The genome of Desulfitobacterium hafniense DCB-2 is composed of a 5,279,134-bp circular chromosome with 5,042 predicted genes. Genome content and parallel physiological studies support the cell's ability to fix N2 and CO2, form spores and biofilms, reduce metals, and use a variety of electron acceptors in respiration, including halogenated organic compounds. The genome contained seven reductive dehalogenase genes and four nitrogenase gene homologs but lacked the Nar respiratory nitrate reductase system. The D. hafniense DCB-2 genome contained genes for 43 RNA polymerase sigma factors including 27 sigma-24 subunits, 59 two-component signal transduction systems, and about 730 transporter proteins. In addition, it contained genes for 53 molybdopterin-binding oxidoreductases, 19 flavoprotein paralogs of the fumarate reductase, and many other FAD/FMN-binding oxidoreductases, proving the cell's versatility in both adaptive and reductive capacities. Together with the ability to form spores, the presence of the CO2-fixing Wood-Ljungdahl pathway and the genes associated with oxygen tolerance add flexibility to the cell's options for survival under stress. Conclusions D. hafniense DCB-2's genome contains genes consistent with its abilities for dehalogenation, metal reduction, N2 and CO2 fixation, anaerobic respiration, oxygen tolerance, spore formation, and biofilm formation which make this organism a potential candidate for bioremediation at contaminated sites.

2012-01-01

258

Cellular fatty acid composition as an adjunct to the identification of asporogenous, aerobic gram-positive rods.  

PubMed

Cellular fatty acid (CFA) compositions of 561 asporogenous, aerobic gram-positive rods were analyzed by gas-liquid chromatography as an adjunct to their identification when grown on blood agar at 35 degrees C. The organisms could be divided into two groups. In the first group (branched-chain type), which included coryneform CDC groups A-3, A-4, and A-5; some strains of B-1 and B-3; "Corynebacterium aquaticum"; Brevibacterium liquefaciens; Rothia dentocariosa; and Listeria spp., the rods had sizable quantities of antiesopentadecanoic (Ca15:0) and anteisoheptadecanoic (Ca17:0) acids. Other species with these types of CFA included B. acetylicum, which contained large amounts of isotridecanoic (Ci13:0) and anteisotridecanoic (Ca13:0) acids. CFAs useful for distinguishing among Jonesia denitrificans, Oerskovia spp., some strains of CDC groups B-1 and B-3, Kurthia spp., and Propionibacterium avidum were hexadecanoic (C 16:0) acid, isopentadecanoic (Ci15:0) acid, and Ca15:0). The second group (straight-chained type), which included Actinomyces pyogenes; Arcanobacterium haemolyticum; C. bovis; C. cystitidis; C. diphtheriae; C. flavescens, "C. gentalium"; C. jeikeium; C. kutscheri; C. matruchotii; C .minutissimum; C. mycetoides; C. pilosum; C. pseudodiphtheriticum; "C. pseudogenitalium"; C. pseudotuberculosis; C. renale; CDC groups 1, 2, ANF-1, D-2, E, F-1, F-2, G-1, G-2, and I-2; C. striatum; "C. tuberculostearicum"; C. ulcerans; C. vitarumen; C. xerosis; and Erysipelothrix rhusiopathiae, was typified by significant quantities of hexadecanoic (C16:0) and oleic acids (C18:cis9), with differences in the amounts of linoleic acid (C18:2), stearic acid (C18:0), an unnamed peak (equivalent chain length, 14.966), and small quantities of other known saturated and unsaturated fatty acids. CFA composition of these organisms was sufficiently discriminatory to assist in classification but could not be used as the sole means of identification. PMID:1899679

Bernard, K A; Bellefeuille, M; Ewan, E P

1991-01-01

259

Horizontal spread of mer operons among Gram-positive bacteria in natural environments  

Microsoft Academic Search

Horizontal dissemination of the genes responsible for resistance to toxic pollutants may play a key role in the adaptation of bacterial populations to environmental contaminants. However, the frequency and extent of gene dissemination in natural environments is not known. A natural horizontal spread of two distinct mercury resistance (mer) operon variants, which occurred amongst diverse Bacillus and related species over

E. S. Bogdanova; I. A. Bass; L. S. Minakhin; M. A. Petrova; S. Z. Mindlin; A. A. Volodin; E. S. Kalyaeva; J. M. Tiedje; J. L. Hobman; N. L. Brown; V. G. Nikiforov

1998-01-01

260

[Antimicrobial susceptibility of clinical isolates of aerobic gram-positive cocci and anaerobic bacteria in 2008].  

PubMed

The activity of antibacterial agents against aerobic Gram-positive cocci (25 genus or species, 1029 strains) and anaerobic bacteria (21 genus or species, 187 strains) isolated from clinical specimens in 2008 at 16 clinical facilities in Japan were studied using either broth microdilution or agar dilution method. The ratio of methicillin-resistant strains among Staphylococcus aureus and Staphylococcus epidermidis was 59.6% and 81.2%, suggesting that resistant strains were isolated at high frequency. Vancomycin (VCM), linezolid (LZD) and quinupristin/dalfopristin (QPR/DPR) had good antibacterial activity against methicillin-resistant S. aureus and methicillin-resistant S. epidermidis, with MIC90s of < or = 2 microg/mL. The ratio of penicillin (PC) intermediate and resistant strains classified by mutations of PC-binding proteins among Streptococcus pneumoniae was 92.0% that was highest among our previous reports. Cefpirome, carbapenems, VCM, teicoplanin (TEIC), LZD and QPR/DPR had MIC90s of < or = 1 microg/mL against PC-intermediate and resistant S. pneumoniae strains. Against all strains of Enterococcus faecalis and Enterococcus faecium, the MICs of VCM and TEIC were under 2 microg/mL, and no resistant strain was detected, suggesting that these agents had excellent activities against these species. 15.9% of E. faecalis strains and 1.2% of E. faecium strains showed intermediate to LZD. 17.1% of E. faecium strains showed intermediate or resistant to QPR/DPR. Against all strains of Clostridium difficile, the MIC of VCM was under 1 microg/mL, suggesting that VCM had excellent activity. Carbapenems showed good activity against Clostridiales, Bacteroides spp., and Prevotella spp., but one strain of Bacteroides fragilis showed resistant to carbapenems. And so, the susceptibility of this species should be well-focused in the future at detecting continuously. PMID:22808693

Yoshida, Isamu; Yamaguchi, Takahiro; Kudo, Reiko; Fuji, Rieko; Takahashi, Choichiro; Oota, Reiko; Kaku, Mitsuo; Kunishima, Hiroyuki; Okada, Masahiko; Horikawa, Yoshinori; Shiotani, Joji; Kino, Hiroyoshi; Ono, Yuka; Fujita, Shinichi; Matsuo, Shuji; Kono, Hisashi; Asari, Seishi; Toyokawa, Masahiro; Kusano, Nobuchika; Nose, Motoko; Horii, Toshinobu; Tanimoto, Ayako; Miyamoto, Hitoshi; Saikawa, Tetsunori; Hiramatsu, Kazufumi; Kohno, Shigeru; Yanagihara, Katsunori; Yamane, Nobuhisa; Nakasone, Isamu; Maki, Hideki; Yamano, Yoshinori

2012-02-01

261

[Antimicrobial susceptibility of clinical isolates of aerobic Gram-positive cocci and anaerobic bacteria in 2006].  

PubMed

The activity of antibacterial agents against aerobic Gram-positive cocci (26 species, 1022 strains) and anaerobic bacteria (23 species, 184 strains) isolated from clinical specimens in 2006 at 16 clinical facilities in Japan were studied using either broth microdilution or agar dilution method. The ratio of methicillin-resistant strains among Staphylococcus aureus and Staphylococcus epidermidis was 53.0% and 65.8%, suggesting that resistant strains were isolated at high frequency. Vancomycin (VCM) and quinupristin/dalfopristin (QPR/DPR) had good antibacterial activity against methicillin-resistant S. aureus and methicillin-resistant S. epidermidis, with MIC90s of < or = 2 micrcog/mL. The ratio of penicillin (PC) intermediate and resistant strains classified by mutations of PC-binding proteins among Streptococcus pneumoniae was 87.6%. Ceftriaxone, cefpirome, cefepime, carbapenem antibiotics, VCM, teicoplanin, linezolid(LZD) and QPR/DPR had MIC90s of < or = 1 microg/mL against PC-intermediate and resistant S. pneumoniae strains. Against all strains of Enterococcus faecalis and Enterococcus faecium, the MICs of VCM and TEIC were under 2 microg/mL, and no resistant strain was detected, suggesting that these agents had excellent activities against these species. 10.9% of E. faecalis strains or 3.5% of E. faecium strains showed intermediate or resistant to LZD. 24.4% of E. faecium strains showed intermediate or resistant to QPR/DPR. Against all strains of Clostridium difficile, the MIC of VCM were under 1 microg/mL, suggesting that VCM had excellent activity against C. difficile. Carbapenems showed good activity against Peptococcaceae, Bacteroides spp., and Prevotella spp. However since several strains of Bacteroides fragilis showed resistant to carbapenems and the susceptibility of this species should be well-focused in the future. PMID:21425596

Yamaguchi, Takahiro; Yoshida, Isamu; Itoh, Yoshihisa; Tachibana, Mineji; Takahashi, Choichiro; Kaku, Mitsuo; Kanemitsu, Keiji; Okada, Masahiko; Horikawa, Yoshinori; Shiotani, Joji; Kino, Hiroyoshi; Ono, Yuka; Baba, Hisashi; Matsuo, Shuji; Asari, Seishi; Toyokawa, Masahiro; Matsuoka, Kimiko; Kusano, Nobuchika; Nose, Motoko; Murase, Mitsuharu; Miyamoto, Hitoshi; Saikawa, Tetsunori; Hiramatsu, Kazufumi; Kohno, Shigeru; Yanagihara, Katsunori; Yamane, Nobuhisa; Nakasone, Isamu; Maki, Hideki; Yamano, Yoshinori

2010-12-01

262

Gram Positive Bacteria Induce IL6 and IL8 Production in Human Alveolar Macrophages and Epithelial Cells  

Microsoft Academic Search

Background and Objective: Inhalation of dust from swine confinement buildings results in an acute inflammatory reaction in the respiratory tract. The dust has a high microbial content, dominated by Gram positive bacteria. The aim of the present study was to evaluate the significance of bacteria in the induction of IL-6 and IL-8 release from respiratory epithelial cells and alveolar macrophages.

Britt-Marie Larsson; Kjell Larsson; Per Malmberg; Lena Palmberg

1999-01-01

263

Detection of toxigenic Bacillus cereus and Bacillus thuringiensis spores in U.S. rice  

Microsoft Academic Search

Bacillus cereus is a gram-positive, endospore forming pathogenic bacterium that is ubiquitous in the environment and is frequently associated with emetic and diarrheal types of foodborne illness. In this study, 178 samples of raw rice from retail food stores were analyzed for the presence of B. cereus spores. Spores of Bacillus species were found in 94 (52.8%) of the rice

Chandrakant Ankolekar; Talat Rahmati; Ronald G. Labbé

2009-01-01

264

Clinical cure and survival in Gram-positive ventilator-associated pneumonia: retrospective analysis of two double-blind studies comparing linezolid with vancomycin  

Microsoft Academic Search

Objective To assess the effect of baseline variables, including treatment, on clinical cure and survival rates in patients with Gram-positive, ventilator-associated pneumonia (VAP). Design Retrospective analysis of two randomized, double-blind studies. Setting Multinational study with 134 sites. Patients 544 patients with suspected Gram-positive VAP, including 264 with documented Gram-positive VAP and 91 with methicillin-resistant S. aureus (MRSA) VAP. Interventions Linezolid

Marin H. Kollef; Jordi Rello; Sue K. Cammarata; Rodney V. Croos-Dabrera; Richard G. Wunderink

2004-01-01

265

Plantazolicin, a Novel Microcin B17/Streptolysin S-Like Natural Product from Bacillus amyloliquefaciens FZB42 ?  

PubMed Central

Here we report on a novel thiazole/oxazole-modified microcin (TOMM) from Bacillus amyloliquefaciens FZB42, a Gram-positive soil bacterium. This organism is well known for stimulating plant growth and biosynthesizing complex small molecules that suppress the growth of bacterial and fungal plant pathogens. Like microcin B17 and streptolysin S, the TOMM from B. amyloliquefaciens FZB42 undergoes extensive posttranslational modification to become a bioactive natural product. Our data show that the modified peptide bears a molecular mass of 1,335 Da and displays antibacterial activity toward closely related Gram-positive bacteria. A cluster of 12 genes that covers ?10 kb is essential for the production, modification, export, and self-immunity of this natural product. We have named this compound plantazolicin (PZN), based on the association of several producing organisms with plants and the incorporation of azole heterocycles, which derive from Cys, Ser, and Thr residues of the precursor peptide.

Scholz, Romy; Molohon, Katie J.; Nachtigall, Jonny; Vater, Joachim; Markley, Andrew L.; Sussmuth, Roderich D.; Mitchell, Douglas A.; Borriss, Rainer

2011-01-01

266

Bacillus as PGPR in Crop Ecosystem  

Microsoft Academic Search

\\u000a Gram-positive bacteria, in particular, members of group Bacillus, are among the best-studied experimental systems in bacteriology. Research, in Bacillus subtilis is remarkably diverse, including genetics, biochemistry, cell biology, and ecology, thus has an enormous impact on both basic\\u000a and applied biology. Multiple species of Bacillus and Paenibacillus occur in the agricultural fields that can promote the crop health in different

Ankit Kumar; Anil Prakash; B. N. Johri

267

The terminally redundant, nonpermuted genome of Listeria bacteriophage A511: a model for the SPO1-like myoviruses of gram-positive bacteria.  

PubMed

Only little information on a particular class of myoviruses, the SPO1-like bacteriophages infecting low-G+C-content, gram-positive host bacteria (Firmicutes), is available. We present the genome analysis and molecular characterization of the large, virulent, broad-host-range Listeria phage A511. A511 contains a unit (informational) genome of 134,494 bp, encompassing 190 putative open reading frames (ORFs) and 16 tRNA genes, organized in a modular fashion common among the Caudovirales. Electron microscopy, enzymatic fragmentation analyses, and sequencing revealed that the A511 DNA molecule contains linear terminal repeats of a total of 3,125 bp, encompassing nine small putative ORFs. This particular genome structure explains why A511 is unable to perform general transduction. A511 features significant sequence homologies to Listeria phage P100 and other morphologically related phages infecting Firmicutes such as Staphylococcus phage K and Lactobacillus phage LP65. Equivalent but more-extensive terminal repeats also exist in phages P100 (approximately 6 kb) and K (approximately 20 kb). High-resolution electron microscopy revealed, for the first time, the presence of long tail fibers organized in a sixfold symmetry in these viruses. Mass spectrometry-based peptide fingerprinting permitted assignment of individual proteins to A511 structural components. On the basis of the data available for A511 and relatives, we propose that SPO1-like myoviruses are characterized by (i) their infection of gram-positive, low-G+C-content bacteria; (ii) a wide host range within the host bacterial genus and a strictly virulent lifestyle; (iii) similar morphology, sequence relatedness, and collinearity of the phage genome organization; and (iv) large double-stranded DNA genomes featuring nonpermuted terminal repeats of various sizes. PMID:18567664

Klumpp, Jochen; Dorscht, Julia; Lurz, Rudi; Bielmann, Regula; Wieland, Matthias; Zimmer, Markus; Calendar, Richard; Loessner, Martin J

2008-06-20

268

In vitro assessment of Ag2O nanoparticles toxicity against Gram-positive and Gram-negative bacteria.  

PubMed

In view of antibiotic resistance among pathogens, the present study is to address the toxicity of Ag2O nanoparticles against the Gram-positive and Gram-negative bacteria through in vitro assays. The preliminary screening by agar diffusion assay confirms the antibacterial activity of Ag2O nanoparticles against all the test bacteria. Comparative antibacterial activity of Ag2O nanoparticles and respective antibiotics reveals their broad range of activity and lower inhibitory dose against the used bacterial strains. Further, they can inhibit E. coli with an effective dose of 0.036 mg/ml within 1 h of exposure time as determined by luciferin based ATP assay. Moreover, the Ag2O nanoparticles exhibit higher antibacterial efficacy against Gram-negative bacteria than Gram-positive bacteria, as revealed by their MIC & MBC values. Therefore, Ag2O nanoparticles pave the way for a new generation of antibacterial agents against the emerging multidrug resistant pathogens. PMID:23518522

Negi, Harshita; Rathinavelu Saravanan, Palaniyandi; Agarwal, Tithi; Ghulam Haider Zaidi, Mohd; Goel, Reeta

2013-01-01

269

Meso-substituted cationic porphyrins as efficient photosensitizers of gram-positive and gram-negative bacteria  

Microsoft Academic Search

Previous studies on the photosensitization of bacterial cells with different neutral or negatively charged porphyrins and phthalocyanines have demonstrated that, although Gram-positive bacteria are efficiently photoinactivated, Gram-negatrive bacteria become photosensitive only after modification of the permeability of their outer membrane.The results described in this paper show that two meso-substituted cationic porphyrins, namely tetra(4N-methyl-pyridyl) porphine tetraiodide and the tetra(4N,N,N,-trimethyl-anilinium) porphine, efficiently

Michèle Merchat; Giulio Bertolini; Paolo Giacomini; Angeles Villaneuva; Giulio Jori

1996-01-01

270

Midterm results after treatment of gram-positive deep sternal wound infections with daptomycin for cardiac surgery patients  

PubMed Central

Daptomycin in combination with surgical therapy has shown to be effective for treatment of deep sternal wound infection in cardiac surgery. However, till now midterm results in terms of re-infection or re-operation in patients who were successfully treated with daptomycin for gram-positive deep sternal wound infection are not published. Herein, we present midterm results in patients treated successfully with daptomycin after cardiac surgery.

2013-01-01

271

Vancomycin vs teicoplanin in the treatment of Gram-positive infections: a pharmacoeconomic analysis in a Turkish University Hospital  

Microsoft Academic Search

Objective The aim of this study was to estimate and compare the costs of vancomycin and teicoplanin in the treatment of Gram-positive\\u000a hospital infections in Turkey using a cost minimisation analysis. Setting Hacettepe University Hospital, Ankara, Turkey. Method The health-care provider’s perspective was considered within formal pharmacoeconomic assessment methodology. The records\\u000a of 76 patients who had been hospitalised and treated

Aylin Acar Sancar; Selen Yegenoglu; Robin de Vries; Maarten J. Postma; Nimet Simsek; Petros Pechlivanoglou; Serhat Unal

2008-01-01

272

Palmitoleic Acid Isomer (C16:1?6) in Human Skin Sebum Is Effective against Gram-Positive Bacteria  

Microsoft Academic Search

The percent lipid composition of pooled human sebum analyzed by thin-layer chromatography was: ceramides (13%), fatty acid (47%), cholesterol (7%), cholesterol esters (2%), squalene (11%), triglycerides (3%), and wax esters (17%). Total sebum lipids (2– 4 mg\\/ml), sonicated into bacterial culture medium, caused 4- to 5-fold log reduction in growth of gram-positive bacteria, Staphylococcus aureus, Streptococcus salivarius and the anaerobe

J. J. Wille; A. Kydonieus

2003-01-01

273

Photoinactivation effects of hematoporphyrin monomethyl ether on Gram-positive and -negative bacteria detected by atomic force microscopy  

Microsoft Academic Search

The photodynamic antimicrobial chemotherapy as a promising approach for efficiently killing pathogenic microbes is attracting\\u000a increasing interest. In this study, the cytotoxic and phototoxic effects of hematoporphyrin monomethyl ether (HMME) on the\\u000a Gram-positive and Gram-negative bacteria were investigated. The cell viability was assessed by colony-forming unit method,\\u000a and the results indicated that there was no significant cytotoxicity but high phototoxicity

Hua Jin; Xun Huang; Yong Chen; Hongxia Zhao; Hongyan Ye; Feicheng Huang; Xiaobo Xing; Jiye Cai

2010-01-01

274

Effects of cell structure of gram-positive and gram-negative bacteria based on their dielectric properties  

Microsoft Academic Search

Current procedures for the identification and characterization of microorganisms are based on complex and time-consuming protocols. Here, we hypothesize that the distinct cellular composition of microorganisms could be identified by dielectric spectroscopy. Gram-positive and Gram-negative bacterial strain permittivity measurement was performed using a network analyzer and a coaxial probe in the frequency range from 50 MHz to 300 MHz. All

Katja Dahlke; Christiane Geyer; Stephan Dees; Marko Helbig; Jurgen Sachs; Francesco Scotto di Clemente; Matthias Hein; Werner Alois Kaiser; Ingrid Hilger

2012-01-01

275

Secretory Phospholipase A2 Is the Principal Bactericide for Staphylococci and Other Gram-Positive Bacteria in Human Tears  

Microsoft Academic Search

We examined human tears for molecules that killed gram-positive bacteria. The principal mediator of bactericidal activity against staphylococci proved to be a calcium-dependent enzyme, secretory phospholipase A2. Whereas the concentration of secretory phospholipase A2 in the normal tear film exceeded 30 mg\\/ml, only 1.1 ng (<0.1 nM) of the enzyme per ml sufficed to kill Listeria monocytogenes and 15 to

XIAO-DAN QU; ROBERT I. LEHRER

1998-01-01

276

Evaluation of Susceptibility of Gram-Positive and Negative Bacteria to Human Defensins by Using Radial Diffusion Assay  

Microsoft Academic Search

Defensinsaresmallcationicbactericidalpeptidespresentabundantlyinthegranulesofpolymorphonuclear neutrophils (PMNs). Human PMNs contain four defensins termed HNP-1 to HNP-4. We used a new assay system in agar plates, the radial diffusion assay, to evaluate the effects of human defensins against gram- positive and -negative bacteria. A crude mixture of HNP-1, -2, and -3 (crude HNPs) was purified from human PMN extracts by reversed-phase high-pressure liquid chromatography (RP-HPLC).

HIROMU TAKEMURA; MITSUO KAKU; SHIGERU KOHNO; YOICHI HIRAKATA; HIRONORI TANAKA; RYOJI YOSHIDA; KAZUNORI TOMONO; HIRONOBU KOGA; AKIHIRO WADA; TOSHIYA HIRAYAMA; ANDSHIMERU KAMIHIRA

1996-01-01

277

Hexavalent chromium reduction by a dichromate-resistant gram-positive bacterium isolated from effluents of tanneries  

Microsoft Academic Search

A gram-positive, chromium (Cr)-resistant bacterial strain (ATCC 700729) was isolated from effluent of tanneries. It was grown\\u000a in media containing potassium dichromate concentration up to 80?mg?ml?1 of the medium. The dichromate reducing capability of the bacterium was checked by estimating the amount of Cr VI in the medium\\u000a before and after introduction of bacterial culture. The influence of factors like

A. R. Shakoori; M. Makhdoom; R. U. Haq

2000-01-01

278

Soluble bacterial constituents down-regulate secretion of IL12 in response to intact Gram-positive bacteria  

Microsoft Academic Search

Intact Gram-positive bacteria induce production of large amounts of IL-12 from freshly isolated human monocytes. Here the bacterial structures and signalling pathways involved were studied and compared with those leading to IL-6 production, and to IL-12 production in response to LPS after IFN-? pre-treatment. Intact bifidobacteria induced massive production of IL-12 (1ng\\/ml) and IL-6 (>30ng\\/ml) from human PBMC, whereas fragmented

Cecilia Barkman; Anna Martner; Christina Hessle; Agnes E. Wold

2008-01-01

279

On the target of a novel class of antibiotics, oxazolidinones, active against multidrug-resistant Gram-positive bacteria  

Microsoft Academic Search

Oxazolidinones are a promising new class of synthetic antibiotics active against multidrug-resistant Gram-positive bacteria. To elucidate their mode of action, the effect of DuP 721 on individual steps of protein translation was studied. The drug does not interfere with translation initiation at the stage of mRNA binding or formation of 30S pre-initiation complexes. However, it inhibits the puromycin-mediated release of

Helena Burghardt; Karl-Ludwig Schimz; Matthias Müller

1998-01-01

280

Activity of linezolid against multi-resistant Gram-positive bacteria from diverse hospitals in the United Kingdom  

Microsoft Academic Search

The in vitro activity of linezolid, an oxazolidinone, was assessed against 374 Gram-positive cocci, with an emphasis on testing multi-resistant, epidemiologically unrelated isolates. MICs of linezolid for staphylococci, pneumococci and streptococci had a narrow range, from 0.5 to 2 mg\\/L, whereas MICs for enterococci were uniformly 4 mg\\/L. For all the species tested, the MICs of linezolid were unrelated to

Alan P. Johnson; Marina Warner; David M. Livermore

2000-01-01

281

Improved Pattern for Genome-Based Screening Identifies Novel Cell Wall-Attached Proteins in Gram-Positive Bacteria  

Microsoft Academic Search

With a large number of sequenced microbial genomes available, tools for identifying groups or classes of proteins have become increasingly important. Here we present an improved pattern for the identification of cell wall-attached proteins (CWPs), a group of proteins with diverse and important functions in gram-positive bacteria. This tripartite pattern is based on analysis of 65 previously described cell wall-attached

ROBERT JANULCZYK; MAGNUS RASMUSSEN

2001-01-01

282

Coexistence of CD14Dependent and Independent Pathways for Stimulation of Human Monocytes by Gram-Positive Bacteria  

Microsoft Academic Search

The cell wall is a key inflammatory agent of gram-positive bacteria. Possible receptors mediating cell wall-induced inflammation include CD14 and platelet-activating factor (PAF) receptor. To delineate the conditions under which these various receptors might be used, human monocytic THP-1 cells and heparinized whole human blood were stimulated with lipopolysaccharide (LPS), intact Streptococcus pneumoniae bacteria, or purified pneumococcal cell wall. THP-1

ANJE CAUWELS; ELAINE WAN; MICHAELA LEISMANN; ELAINE TUOMANEN

1997-01-01

283

Studies on the aminopeptidase test for the distinction of gram-negative from gram-positive bacteria  

Microsoft Academic Search

The aminopeptidase test was performed with representatives of gram-negative, gram-positive, and gram-variable bacteria. All gram-negative bacteria tested gave a positive test reaction with L-alanine-4-nitroanilide as test substrate. Representatives of the coryneform bacteria and some streptococci showed aminopeptidase activity after prolonged reaction times. A correlation between aminopeptidase activity and distinct interpeptide bridge composition in the peptidoglycan of many strains was demonstrated.

G. Cerny

1978-01-01

284

In Vitro Activities of Linezolid against Important Gram-Positive Bacterial Pathogens Including Vancomycin-Resistant Enterococci  

Microsoft Academic Search

The emergence of resistance in gram-positive bacteria has necessitated a search for new antimicrobial agents. Linezolid is an oxazolidinone, a new class of antibacterial agents with enhanced activity against pathogens. We compared the activity of linezolid to those of other antimicrobial agents against 3,945 clinical isolates. Linezolid demonstrated potent activity against all isolates tested. For all vancomycin-susceptible enterococci, staphylococci, and

GARY A. NOSKIN; FARIDA SIDDIQUI; VALENTINA STOSOR; DONNA HACEK; LANCE R. PETERSON

1999-01-01

285

Midterm results after treatment of gram-positive deep sternal wound infections with daptomycin for cardiac surgery patients.  

PubMed

Daptomycin in combination with surgical therapy has shown to be effective for treatment of deep sternal wound infection in cardiac surgery. However, till now midterm results in terms of re-infection or re-operation in patients who were successfully treated with daptomycin for gram-positive deep sternal wound infection are not published. Herein, we present midterm results in patients treated successfully with daptomycin after cardiac surgery. PMID:23351310

Ort, Katharina R; Jebran, Fawad A; Bireta, Christian; Danner, Bernhard C; Bougioukas, Ioannis; Schoendube, Friedrich A; Popov, Aron F

2013-01-26

286

Development of a Thermally Regulated Broad-Spectrum Promoter System for Use in Pathogenic Gram-Positive Species  

PubMed Central

Selectively regulating gene expression is an essential molecular tool that is lacking for many pathogenic gram-positive bacteria. In this report, we describe the evaluation of a series of promoters regulated by the bacteriophage P1 temperature-sensitive C1 repressor in Enterococcus faecium, Enterococcus faecalis, and Staphylococcus aureus. Using the lacZ gene to monitor gene expression, we examined the strength, basal expression, and induced expression of synthetic promoters carrying C1 operator sites. The promoters exhibited extremely low basal expression and, under inducing conditions, gave high levels of expression (100- to 1,000-fold induction). We demonstrate that the promoter system could be modulated by temperature and showed rapid induction and that the mechanism of regulation occurred at the level of transcription. Controlled expression with the same constructs was also demonstrated in the gram-negative bacterium Escherichia coli. However, low basal expression and the ability to achieve derepression were dependent on both the number of mismatches in the C1 operator sites and the promoter driving c1 expression. Since the promoters were designed to contain conserved promoter elements from gram-positive species and were constructed in a broad-host-range plasmid, this system will provide a new opportunity for controlled gene expression in a variety of gram-positive bacteria.

Schofield, David A.; Westwater, Caroline; Hoel, Brian D.; Werner, Phillip A.; Norris, James S.; Schmidt, Michael G.

2003-01-01

287

Ribosomal DNA Sequencing for Identification of Aerobic Gram-Positive Rods in the Clinical Laboratory (an 18-Month Evaluation)  

PubMed Central

We have evaluated over a period of 18 months the use of 16S ribosomal DNA (rDNA) sequence analysis as a means of identifying aerobic gram-positive rods in the clinical laboratory. Two collections of strains were studied: (i) 37 clinical strains of gram-positive rods well identified by phenotypic tests, and (ii) 136 clinical isolates difficult to identify by standard microbiological investigations, i.e., identification at the species level was impossible. Results of molecular analyses were compared with those of conventional phenotypic identification procedures. Good overall agreement between phenotypic and molecular identification procedures was found for the collection of 37 clinical strains well identified by conventional means. For the 136 clinical strains which were difficult to identify by standard microbiological investigations, phenotypic characterization identified 71 of 136 (52.2%) isolates at the genus level; 65 of 136 (47.8%) isolates could not be discriminated at any taxonomic level. In comparison, 16S rDNA sequencing identified 89 of 136 (65.4%) isolates at the species level, 43 of 136 (31.6%) isolates at the genus level, and 4 of 136 (2.9%) isolates at the family level. We conclude that (i) rDNA sequencing is an effective means for the identification of aerobic gram-positive rods which are difficult to identify by conventional techniques, and (ii) molecular identification procedures are not required for isolates well identified by phenotypic investigations.

Bosshard, P. P.; Abels, S.; Zbinden, R.; Bottger, E. C.; Altwegg, M.

2003-01-01

288

[Evaluation of API Coryne System, version 2.0, for diphteroid gram-positive rods identification with clinical relevance].  

PubMed

The ability of the API Coryne system, version 2.0, to identify 178 strains of gram-positive rods was evaluated. Seventy eight isolates belonged to genus Corynebacterium and one hundred to related genera, all strains were isolated from clinical samples at the Laboratory of Bacteriology, Hospital de Clínicas José de San Martin (UBA) between 1995 and 2004. The isolates were identified according to von Graevenitz and Funke's scheme. One hundred and sixty two out of 178 strains (91%) were correctly identified at genus and species level (IC95 = 85.6-94.6), in 44 of them (24.7%) additional tests were needed to final identification. Sixteen strains (9%) were not correctly identified (IC95 = 5.4-14.4); none of the 178 strains remained unidentified. The API Coryne system, version 2.0, is useful to identify the majority of Cory-nebacterium species with clinical relevance: Corynebacterium jeikeium, Corynebacterium urealyticum, Corynebacterium striatum, Corynebacterium pseudodiphtheriticum, Corynebacterium amycolatum and related species such as Arcanobacterium haemolyticum, Dermabacter hominis, Listeria monocytogenes, among others. Nevertheless for yellow-pigmented diphteroid gram-positive rods (Aureobacterium spp., Leifsonia aquatica, Microbacterium spp. and Cellulomonas spp.) and for acid fast gram-positive rods (Rhodococcus, Gordonia, Tsukamurella and Nocardia) the identification usefulness the system is limited. PMID:17370571

Almuzara, M N; De Mier, C; Rodríguez, C R; Famiglietti, A M R; Vay, C A

289

In Vitro Activities of Dalbavancin and Nine Comparator Agents against Anaerobic Gram-Positive Species and Corynebacteria  

PubMed Central

Dalbavancin is a novel semisynthetic glycopeptide with enhanced activity against gram-positive species. Its comparative in vitro activities and those of nine comparator agents, including daptomycin, vancomycin, linezolid, and quinupristin-dalfopristin, against 290 recent gram-positive clinical isolates strains, as determined by the NCCLS agar dilution method, were studied. The MICs of dalbavancin at which 90% of various isolates tested were inhibited were as follows: Actinomyces spp., 0.5 ?g/ml; Clostridium clostridioforme, 8 ?g/ml; C. difficile, 0.25 ?g/ml; C. innocuum, 0.25 ?g/ml; C. perfringens, 0.125 ?g/ml; C. ramosum, 1 ?g/ml; Eubacterium spp., 1 ?g/ml; Lactobacillus spp., >32 ?g/ml, Propionibacterium spp., 0.5 ?g/ml; and Peptostreptococcus spp., 0.25 ?g/ml. Dalbavancin was 1 to 3 dilutions more active than vancomycin against most strains. Dalbavancin exhibited excellent activity against gram-positive strains tested and warrants clinical evaluation.

Goldstein, Ellie J. C.; Citron, Diane M.; Merriam, C. Vreni; Warren, Yumi; Tyrrell, Kerin; Fernandez, Helen T.

2003-01-01

290

Probing the relationship between Gram-negative and Gram-positive S1 proteins by sequence analysis  

PubMed Central

Escherichia coli ribosomal protein S1 is required for the translation initiation of messenger RNAs, in particular when their Shine–Dalgarno sequence is degenerated. Closely related forms of the protein, composed of the same number of domains (six), are found in all Gram-negative bacteria. More distant proteins, generally formed of fewer domains, have been identified, by sequence similarities, in Gram-positive bacteria and are also termed ‘S1 proteins’. However in the absence of functional information, it is generally difficult to ascertain their relationship with Gram-negative S1. In this article, we report the solution structure of the fourth and sixth domains of the E. coli protein S1 and show that it is possible to characterize their ?-barrel by a consensus sequence that allows a precise identification of all domains in Gram-negative and Gram-positive S1 proteins. In addition, we show that it is possible to discriminate between five domain types corresponding to the domains 1, 2, 3, 4–5 and 6 of E. coli S1 on the basis of their sequence. This enabled us to identify the nature of the domains present in Gram-positive proteins and, subsequently, to probe the filiations between all forms of S1.

Salah, Philippe; Bisaglia, Marco; Aliprandi, Pascale; Uzan, Marc; Sizun, Christina; Bontems, Francois

2009-01-01

291

Development of a treatment algorithm for streptococci and enterococci from positive blood cultures identified with the verigene gram-positive blood culture assay.  

PubMed

Seventy-eight blood cultures with a Gram stain result of Gram-positive cocci in pairs and/or chains were evaluated with the Nanosphere Verigene Gram-positive blood culture (BC-GP) assay. The overall concordance of the assay with culture was 89.7% (70/78 cultures), allowing for the development of a targeted treatment algorithm. PMID:23985910

Alby, Kevin; Daniels, Lindsay M; Weber, David J; Miller, Melissa B

2013-08-28

292

Bacillus marcorestinctum sp. nov., a Novel Soil Acylhomoserine Lactone Quorum-Sensing Signal Quenching Bacterium  

PubMed Central

A Gram-positive, facultatively anaerobic, endospore-forming and rod-shaped bacterium was isolated from soil samples and designated strain LQQ. This organism strongly quenches the acylhomoserine lactone quorum-sensing signal. The LQQ strain exhibits phenotypic characteristics consistent with its classification in the genus Bacillus. It is positive in catalase and no special growth factor is needed. It uses glucose as sole carbon source. The DNA G + C content is 39.8 mol %. The closest relatives based on the 16S rRNA gene sequence are Bacillus anthracis, Bacillus thuringiensis, and Brevibacillus brevis (syn. Bacillus brevis) with the similarity of 96.5%. The DNA–DNA hybridization data indicates a low level of genomic relatedness with the relative type strains of Bacillus thuringiensis (6.1%), Bacillus anthracis (10.5%) and Brevibacillus brevis (8.7%). On the basis of the phenotypic and phylogenetic data together with the genomic distinctiveness, the LQQ strain represents a novel species of the genus Bacillus, for which the name Bacillus marcorestinctum sp. nov. is proposed. The type strain is LQQT.

Han, Yan; Chen, Fang; Li, Nuo; Zhu, Bo; Li, Xianzhen

2010-01-01

293

Detection of Bacillus anthracis spores: comparison of quantum dot and organic dye labeling agents  

Microsoft Academic Search

Organic dyes are routinely used in labeling assays and sensing of biological molecules. Semiconductor quantum dots (QDs) have attractive features, particularly good resistance to photobleaching and narrow emission bands, which make them potential replacements for organic dyes. Using a previously identified synthetic peptide, a QD, and the R-phycoerythrin (RPE) dye, we have examined various labeling strategies for detecting Bacillus anthracis

William C. Schumacher; Andrew J. Phipps; Prabir K. Dutta

2009-01-01

294

Non contiguous-finished genome sequence and description of Bacillus massiliosenegalensis sp. nov.  

PubMed Central

Bacillus massiliosenegalensis strain JC6T sp. nov. is the type strain of Bacillus massiliosenegalensis sp. nov., a new species within the genus Bacillus. This strain was isolated from the fecal flora of a healthy Senegalese patient. B. massiliosenegalensis is an aerobic Gram-positive rod-shaped bacterium. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 4,981,278-bp long genome comprises a 4,957,301-bp chromosome and a 23,977-bp plasmid. The chromosome contains 4,925 protein-coding and 72 RNA genes, including 4 rRNA genes. The plasmid contains 29 protein-coding genes.

Ramasamy, Dhamodharan; Lagier, Jean-Christophe; Gorlas, Aurore; Raoult, Didier

2013-01-01

295

Multicenter evaluation of the Vitek MS matrix-assisted laser desorption ionization-time of flight mass spectrometry system for identification of Gram-positive aerobic bacteria.  

PubMed

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF) is gaining momentum as a tool for bacterial identification in the clinical microbiology laboratory. Compared with conventional methods, this technology can more readily and conveniently identify a wide range of organisms. Here, we report the findings from a multicenter study to evaluate the Vitek MS v2.0 system (bioMérieux, Inc.) for the identification of aerobic Gram-positive bacteria. A total of 1,146 unique isolates, representing 13 genera and 42 species, were analyzed, and results were compared to those obtained by nucleic acid sequence-based identification as the reference method. For 1,063 of 1,146 isolates (92.8%), the Vitek MS provided a single identification that was accurate to the species level. For an additional 31 isolates (2.7%), multiple possible identifications were provided, all correct at the genus level. Mixed-genus or single-choice incorrect identifications were provided for 18 isolates (1.6%). Although no identification was obtained for 33 isolates (2.9%), there was no specific bacterial species for which the Vitek MS consistently failed to provide identification. In a subset of 463 isolates representing commonly encountered important pathogens, 95% were accurately identified to the species level and there were no misidentifications. Also, in all but one instance, the Vitek MS correctly differentiated Streptococcus pneumoniae from other viridans group streptococci. The findings demonstrate that the Vitek MS system is highly accurate for the identification of Gram-positive aerobic bacteria in the clinical laboratory setting. PMID:23658261

Rychert, Jenna; Burnham, Carey-Ann D; Bythrow, Maureen; Garner, Omai B; Ginocchio, Christine C; Jennemann, Rebecca; Lewinski, Michael A; Manji, Ryhana; Mochon, A Brian; Procop, Gary W; Richter, Sandra S; Sercia, Linda; Westblade, Lars F; Ferraro, Mary Jane; Branda, John A

2013-05-08

296

A type IV-secretion-like system is required for conjugative DNA transport of broad-host-range plasmid pIP501 in gram-positive bacteria.  

PubMed

Plasmid pIP501 has a very broad host range for conjugative transfer among a wide variety of gram-positive bacteria and gram-negative Escherichia coli. Functionality of the pIP501 transfer (tra) genes in E. coli was proven by pIP501 retrotransfer to Enterococcus faecalis (B. Kurenbach, C. Bohn, J. Prabhu, M. Abudukerim, U. Szewzyk, and E. Grohmann, Plasmid 50:86-93, 2003). The 15 pIP501 tra genes are organized in a single operon (B. Kurenbach, J. Kope?, M. Mägdefrau, K. Andreas, W. Keller, C. Bohn, M. Y. Abajy, and E. Grohmann, Microbiology 152:637-645, 2006). The pIP501 tra operon is negatively autoregulated at the transcriptional level by the conjugative DNA relaxase TraA. Three of the 15 pIP501-encoded Tra proteins show significant sequence similarity to the Agrobacterium type IV secretion system proteins VirB1, VirB4, and VirD4. Here we report a comprehensive protein-protein interaction map of all of the pIP501-encoded Tra proteins determined by the yeast two-hybrid assay. Most of the interactions were verified in vitro by isolation of the protein complexes with pull-down assays. In conjunction with known or postulated functions of the pIP501-encoded Tra proteins and computer-assisted prediction of their cellular location, we propose a model for the first type IV-secretion-like system encoded by a conjugative plasmid from gram-positive bacteria. PMID:17209024

Abajy, Mohammad Y; Kope?, Jolanta; Schiwon, Katarzyna; Burzynski, Michal; Döring, Mike; Bohn, Christine; Grohmann, Elisabeth

2007-01-05

297

A Type IV-Secretion-Like System Is Required for Conjugative DNA Transport of Broad-Host-Range Plasmid pIP501 in Gram-Positive Bacteria?  

PubMed Central

Plasmid pIP501 has a very broad host range for conjugative transfer among a wide variety of gram-positive bacteria and gram-negative Escherichia coli. Functionality of the pIP501 transfer (tra) genes in E. coli was proven by pIP501 retrotransfer to Enterococcus faecalis (B. Kurenbach, C. Bohn, J. Prabhu, M. Abudukerim, U. Szewzyk, and E. Grohmann, Plasmid 50:86-93, 2003). The 15 pIP501 tra genes are organized in a single operon (B. Kurenbach, J. Kope?, M. Mägdefrau, K. Andreas, W. Keller, C. Bohn, M. Y. Abajy, and E. Grohmann, Microbiology 152:637-645, 2006). The pIP501 tra operon is negatively autoregulated at the transcriptional level by the conjugative DNA relaxase TraA. Three of the 15 pIP501-encoded Tra proteins show significant sequence similarity to the Agrobacterium type IV secretion system proteins VirB1, VirB4, and VirD4. Here we report a comprehensive protein-protein interaction map of all of the pIP501-encoded Tra proteins determined by the yeast two-hybrid assay. Most of the interactions were verified in vitro by isolation of the protein complexes with pull-down assays. In conjunction with known or postulated functions of the pIP501-encoded Tra proteins and computer-assisted prediction of their cellular location, we propose a model for the first type IV-secretion-like system encoded by a conjugative plasmid from gram-positive bacteria.

Abajy, Mohammad Y.; Kopec, Jolanta; Schiwon, Katarzyna; Burzynski, Michal; Doring, Mike; Bohn, Christine; Grohmann, Elisabeth

2007-01-01

298

In Vitro Activities of Daptomycin, Vancomycin, Quinupristin- Dalfopristin, Linezolid, and Five Other Antimicrobials against 307 Gram-Positive Anaerobic and 31 Corynebacterium Clinical Isolates  

PubMed Central

The activities of daptomycin, a cyclic lipopeptide, and eight other agents were determined against 338 strains of gram-positive anaerobic bacteria and corynebacteria by the NCCLS reference agar dilution method with supplemented brucella agar for the anaerobes and Mueller-Hinton agar for the corynebacteria. The daptomycin MICs determined on Ca2+-supplemented (50 mg/liter) brucella agar plates were one- to fourfold lower than those determined in unsupplemented media. Daptomycin was highly active (MICs, ?2 ?g/ml) against many strains including 36 of 37 peptostreptococci, 37 of 48 isolates of the Eubacterium group, and all strains of Propionibacterium spp., Clostridium perfringens, Clostridium difficile, and other Clostridium spp. It was fourfold or greater more active than vancomycin against Clostridium innocuum and 16 of 34 strains of vancomycin-resistant lactobacilli. Three strains of C. difficile for which quinupristin-dalfopristin and linezolid MICs were >8 ?g/ml were inhibited by <1 ?g of daptomycin per ml. Daptomycin MICs were ?4 ?g/ml for most strains of Clostridium clostridioforme, Clostridium paraputrificum, Clostridium tertium, and Clostridium ramosum; the isolates were generally more resistant to other antimicrobials. Daptomycin was two- to fourfold less active against Actinomyces spp. than vancomycin, quinupristin-dalfopristin, or linezolid. Twenty-nine of 31 strains of Corynebacterium spp., including Corynebacterium jeikeium, Corynebacterium amycolatum, and Corynebacterium pseudodiphtheriticum, were inhibited by ?0.25 ?g of daptomycin per ml. For two strains of “Corynebacterium aquaticum,” 8 ?g of daptomycin per ml was required for inhibition. Daptomycin demonstrated very good activities against a broad range of gram-positive organisms including vancomycin-resistant C. innocuum and lactobacillus strains and quinupristin-dalfopristin- and linezolid-resistant C. difficile strains.

Goldstein, Ellie J. C.; Citron, Diane M.; Merriam, C. Vreni; Warren, Yumi A.; Tyrrell, Kerrin L.; Fernandez, Helen T.

2003-01-01

299

In vitro activities of daptomycin, vancomycin, quinupristin- dalfopristin, linezolid, and five other antimicrobials against 307 gram-positive anaerobic and 31 Corynebacterium clinical isolates.  

PubMed

The activities of daptomycin, a cyclic lipopeptide, and eight other agents were determined against 338 strains of gram-positive anaerobic bacteria and corynebacteria by the NCCLS reference agar dilution method with supplemented brucella agar for the anaerobes and Mueller-Hinton agar for the corynebacteria. The daptomycin MICs determined on Ca(2+)-supplemented (50 mg/liter) brucella agar plates were one- to fourfold lower than those determined in unsupplemented media. Daptomycin was highly active (MICs, 8 microg/ml were inhibited by <1 microg of daptomycin per ml. Daptomycin MICs were >or=4 microg/ml for most strains of Clostridium clostridioforme, Clostridium paraputrificum, Clostridium tertium, and Clostridium ramosum; the isolates were generally more resistant to other antimicrobials. Daptomycin was two- to fourfold less active against Actinomyces spp. than vancomycin, quinupristin-dalfopristin, or linezolid. Twenty-nine of 31 strains of Corynebacterium spp., including Corynebacterium jeikeium, Corynebacterium amycolatum, and Corynebacterium pseudodiphtheriticum, were inhibited by gram-positive organisms including vancomycin-resistant C. innocuum and lactobacillus strains and quinupristin-dalfopristin- and linezolid-resistant C. difficile strains. PMID:12499210

Goldstein, Ellie J C; Citron, Diane M; Merriam, C Vreni; Warren, Yumi A; Tyrrell, Kerrin L; Fernandez, Helen T

2003-01-01

300

Antimicrobial activity of Enterococcus Faecium Fair-E 198 against gram-positive pathogens  

PubMed Central

ABSTRACT This study investigated the antimicrobial activity of Enterococcus faecium FAIR-E 198 against Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus. Using the critical-dilution method, the bacteriocin produced by E. faecium FAIR-E 198 inhibited all L. monocytogenes strains evaluated (1,600 to 19,200 AU mL-1). However, none of the B. cereus and S. aureus strains investigated were inhibited. The maximum activity of this bacteriocin (800 AU mL-1) was observed in MRS broth, while the activity in milk was 100 AU mL-1. In the co-cultivation test in milk, B. cereus K1-B041 was reduced to below the detection limit (1.00 log CFU mL-1) after 48 h. E. faecium reduced the initial L. monocytogenes Scott A population by 1 log CFU mL-1 after 3 h at 35°C, However, the pathogen regained growth, reaching 3.68 log CFU mL-1 after 48 h. E. faecium did not influence the growth of S. aureus ATCC 27154 during the 48 h of co-cultivation, Therefore, it can be concluded that the effectiveness of the antimicrobial activity of E. faecium FAIR-E 198 is strictly related to the species and strain of the target microorganism and to the culture medium,

do Nascimento, Maristela da Silva; Moreno, Izildinha; Kuaye, Arnaldo Yoshiteru

2010-01-01

301

Secretory phospholipase A2 in dromedary tears: a host defense against staphylococci and other gram-positive bacteria.  

PubMed

The best known physiologic function of secreted phospholipase A2 (sPLA2) group IIA (sPLA2-IIA) is defense against bacterial infection through hydrolytic degradation of bacterial membrane phospholipids. In fact, sPLA2-IIA effectively kills Gram-positive bacteria and to a lesser extent Gram-negative bacteria and is considered a major component of the eye's innate immune defense system. The antibacterial properties of sPLA2 have been demonstrated in rabbit and human tears. In this report, we have analyzed the bactericidal activity of dromedary tears and the subsequently purified sPLA2 on several Gram-positive bacteria. Our results showed that the sPLA2 displays a potent bactericidal activity against all the tested bacteria particularly against the Staphylococcus strains when tested in the ionic environment of tears. There is a synergic action of the sPLA2 with lysozyme when added to the bacteria culture prior to sPLA2. Interestingly, lysozyme purified from dromedary tears showed a significant bactericidal activity against Listeria monocytogene and Staphylococcus epidermidis, whereas the one purified from human tears displayed no activity against these two strains. We have also demonstrated that Ca(2+) is crucial for the activity of dromedary tear sPLA2 and to a less extent Mg(2+) ions. Given the presence of sPLA2 in tears and intestinal secretions, this enzyme may play a substantial role in innate mucosal and systemic bactericidal defenses against Gram-positive bacteria. PMID:23344945

Ben Bacha, Abir; Abid, Islem

2013-01-24

302

Recognition of Gram-positive Intestinal Bacteria by Hybridoma- and Colostrum-derived Secretory Immunoglobulin A Is Mediated by Carbohydrates*  

PubMed Central

Humans live in symbiosis with 1014 commensal bacteria among which >99% resides in their gastrointestinal tract. The molecular bases pertaining to the interaction between mucosal secretory IgA (SIgA) and bacteria residing in the intestine are not known. Previous studies have demonstrated that commensals are naturally coated by SIgA in the gut lumen. Thus, understanding how natural SIgA interacts with commensal bacteria can provide new clues on its multiple functions at mucosal surfaces. Using fluorescently labeled, nonspecific SIgA or secretory component (SC), we visualized by confocal microscopy the interaction with various commensal bacteria, including Lactobacillus, Bifidobacteria, Escherichia coli, and Bacteroides strains. These experiments revealed that the interaction between SIgA and commensal bacteria involves Fab- and Fc-independent structural motifs, featuring SC as a crucial partner. Removal of glycans present on free SC or bound in SIgA resulted in a drastic drop in the interaction with Gram-positive bacteria, indicating the essential role of carbohydrates in the process. In contrast, poor binding of Gram-positive bacteria by control IgG was observed. The interaction with Gram-negative bacteria was preserved whatever the molecular form of protein partner used, suggesting the involvement of different binding motifs. Purified SIgA and SC from either mouse hybridoma cells or human colostrum exhibited identical patterns of recognition for Gram-positive bacteria, emphasizing conserved plasticity between species. Thus, sugar-mediated binding of commensals by SIgA highlights the currently underappreciated role of glycans in mediating the interaction between a highly diverse microbiota and the mucosal immune system.

Mathias, Amandine; Corthesy, Blaise

2011-01-01

303

Discovery of RWJ-54428 (MC-02,479), a new cephalosporin active against resistant gram-positive bacteria.  

PubMed

The discovery of RWJ-54428 (MC-02,479), a new cephalosporin displaying promising activity against sensitive and resistant Gram-positive bacteria, is described. Progressive structural modification from the previously reported 3-phenylthiocephem MC-02,331 afforded an overall increase in potency against MRSA while retaining other key properties such as acceptable solubility and serum binding. Evaluation of the in vitro potency and in vivo efficacy of a series of closely related compounds resulted in selection of RWJ-54428 (MC-02,479) for further studies. PMID:11213288

Hecker, S J; Glinka, T W; Cho, A; Zhang, Z J; Price, M E; Chamberland, S; Griffith, D; Lee, V J

2000-11-01

304

Antibiotic management of ventilator-associated pneumonia due to antibiotic-resistant gram-positive bacterial infection  

Microsoft Academic Search

Gram-positive cocci, in particular Staphylococcus aureus, account for as much as one-third of all cases of hospital-acquired pneumonia, and treatment has become increasingly complex\\u000a as the proportion of resistant isolates has increased. Methicillin-resistant S. aureus is of particular concern because this pathogen is now associated with hospital-acquired, ventilator-associated, community-acquired,\\u000a and healthcare-associated pneumonia. Antibiotic therapy for ventilator-associated pneumonia is challenging because

M. H. Kollef

2005-01-01

305

Comparison of the d-Glutamate-Adding Enzymes from Selected Gram-Positive and Gram-Negative Bacteria  

PubMed Central

The biochemical properties of the d-glutamate-adding enzymes (MurD) from Escherichia coli, Haemophilus influenzae, Enterococcus faecalis, and Staphylococcus aureus were investigated to detect any differences in the activity of this enzyme between gram-positive and gram-negative bacteria. The genes (murD) that encode these enzymes were cloned into pMAL-c2 fusion vector and overexpressed as maltose-binding protein–MurD fusion proteins. Each fusion protein was purified to homogeneity by affinity to amylose resin. Proteolytic treatments of the fusion proteins with factor Xa regenerated the individual MurD proteins. It was found that these fusion proteins retain d-glutamate-adding activity and have Km and Vmax values similar to those of the regenerated MurDs, except for the H. influenzae enzyme. Substrate inhibition by UDP-N-acetylmuramyl-l-alanine, the acceptor substrate, was observed at concentrations greater than 15 and 30 ?M for E. coli and H. influenzae MurD, respectively. Such substrate inhibition was not observed with the E. faecalis and S. aureus enzymes, up to a substrate concentration of 1 to 2 mM. In addition, the two MurDs of gram-negative origin were shown to require monocations such as NH4+ and/or K+, but not Na+, for optimal activity, while anions such as Cl? and SO42? had no effect on the enzyme activities. The activities of the two MurDs of gram-positive origin, on the other hand, were not affected by any of the ions tested. All four enzymes required Mg2+ for the ligase activity and exhibited optimal activities around pH 8. These differences observed between the gram-positive and gram-negative MurDs indicated that the two gram-negative bacteria may apply a more stringent regulation of cell wall biosynthesis at the early stage of peptidoglycan biosynthesis pathway than do the two gram-positive bacteria. Therefore, the MurD-catalyzed reaction may constitute a fine-tuning step necessary for the gram-negative bacteria to optimally maintain its relatively thin yet essential cell wall structure during all stages of growth.

Walsh, Ann W.; Falk, Paul J.; Thanassi, Jane; Discotto, Linda; Pucci, Michael J.; Ho, Hsu-Tso

1999-01-01

306

Comparison of the D-glutamate-adding enzymes from selected gram-positive and gram-negative bacteria.  

PubMed

The biochemical properties of the D-glutamate-adding enzymes (MurD) from Escherichia coli, Haemophilus influenzae, Enterococcus faecalis, and Staphylococcus aureus were investigated to detect any differences in the activity of this enzyme between gram-positive and gram-negative bacteria. The genes (murD) that encode these enzymes were cloned into pMAL-c2 fusion vector and overexpressed as maltose-binding protein-MurD fusion proteins. Each fusion protein was purified to homogeneity by affinity to amylose resin. Proteolytic treatments of the fusion proteins with factor Xa regenerated the individual MurD proteins. It was found that these fusion proteins retain D-glutamate-adding activity and have Km and Vmax values similar to those of the regenerated MurDs, except for the H. influenzae enzyme. Substrate inhibition by UDP-N-acetylmuramyl-L-alanine, the acceptor substrate, was observed at concentrations greater than 15 and 30 microM for E. coli and H. influenzae MurD, respectively. Such substrate inhibition was not observed with the E. faecalis and S. aureus enzymes, up to a substrate concentration of 1 to 2 mM. In addition, the two MurDs of gram-negative origin were shown to require monocations such as NH4+ and/or K+, but not Na+, for optimal activity, while anions such as Cl- and SO4(2-) had no effect on the enzyme activities. The activities of the two MurDs of gram-positive origin, on the other hand, were not affected by any of the ions tested. All four enzymes required Mg2+ for the ligase activity and exhibited optimal activities around pH 8. These differences observed between the gram-positive and gram-negative MurDs indicated that the two gram-negative bacteria may apply a more stringent regulation of cell wall biosynthesis at the early stage of peptidoglycan biosynthesis pathway than do the two gram-positive bacteria. Therefore, the MurD-catalyzed reaction may constitute a fine-tuning step necessary for the gram-negative bacteria to optimally maintain its relatively thin yet essential cell wall structure during all stages of growth. PMID:10464212

Walsh, A W; Falk, P J; Thanassi, J; Discotto, L; Pucci, M J; Ho, H T

1999-09-01

307

Comparative Activities of Clinafloxacin against Gram-Positive and -Negative Bacteria  

PubMed Central

Activities of clinafloxacin, ciprofloxacin, levofloxacin, sparfloxacin, trovafloxacin, piperacillin, piperacillin-tazobactam, trimethoprim-sulfamethoxazole, ceftazidime, and imipenem against 354 ciprofloxacin-susceptible and -intermediate-resistant organisms were tested by agar dilution. Clinafloxacin yielded the lowest quinolone MICs (?0.5 ?g/ml against ciprofloxacin-susceptible organisms and ?16.0 ?g/ml against ciprofloxacin-intermediate-resistant organisms) compared to those of levofloxacin, trovafloxacin, and sparfloxacin. Ceftazidime, piperacillin alone or combined with tazobactam, trimethoprim-sulfamethoxazole, and imipenem usually yielded higher MICs against ciprofloxacin-resistant strains.

Ednie, Lois M.; Jacobs, Michael R.; Appelbaum, Peter C.

1998-01-01

308

Bacillus cereus and related species.  

PubMed

Bacillus cereus is a gram-positive aerobic or facultatively anaerobic spore-forming rod. It is a cause of food poisoning, which is frequently associated with the consumption of rice-based dishes. The organism produces an emetic or diarrheal syndrome induced by an emetic toxin and enterotoxin, respectively. Other toxins are produced during growth, including phospholipases, proteases, and hemolysins, one of which, cereolysin, is a thiol-activated hemolysin. These toxins may contribute to the pathogenicity of B. cereus in nongastrointestinal disease. B. cereus isolated from clinical material other than feces or vomitus was commonly dismissed as a contaminant, but increasingly it is being recognized as a species with pathogenic potential. It is now recognized as an infrequent cause of serious nongastrointestinal infection, particularly in drug addicts, the immunosuppressed, neonates, and postsurgical patients, especially when prosthetic implants such as ventricular shunts are inserted. Ocular infections are the commonest types of severe infection, including endophthalmitis, panophthalmitis, and keratitis, usually with the characteristic formation of corneal ring abscesses. Even with prompt surgical and antimicrobial agent treatment, enucleation of the eye and blindness are common sequelae. Septicemia, meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections are other manifestations of severe disease. B. cereus produces beta-lactamases, unlike Bacillus anthracis, and so is resistant to beta-lactam antibiotics; it is usually susceptible to treatment with clindamycin, vancomycin, gentamicin, chloramphenicol, and erythromycin. Simultaneous therapy via multiple routes may be required. PMID:8269390

Drobniewski, F A

1993-10-01

309

Role for intracellular platelet-activating factor in the circulatory failure in a model of gram-positive shock.  

PubMed Central

1. This study investigates the effects of two structurally different antagonists of platelet-activating factor (PAF), BN52021 and WEB2086, on the circulatory and renal failure elicited by lipoteichoic acid (LTA) from Staphylococcus aureus (an organism without endotoxin) in anaesthetized rats. 2. Administration of LTA (10 mg kg-1, i.v.) caused hypotension and vascular hyporeactivity to noradrenaline (1 microgram kg-1, i.v.) WEB2086 (5 mg kg-1, i.v., 20 min before and 150 min after LTA) inhibited the delayed fall in mean arterial blood pressure (at 300 min: 99 +/- 6 mmHg vs. 75 +/- 6 mmHg, P < 0.01) and prevented the decrease in pressor response to noradrenaline (at 300 min: 36 +/- 5 mmHg min vs. 17 +/- 5 mmHg min, P < 0.01). Surprisingly, BN52021 (20 mg kg-1, i.v., 20 min before and 150 min after LTA) neither prevented the hypotension (74 +/- 6 mmHg) nor the vascular hyporeactivity (21 +/- 5 mmHg min). However, BN52021 inhibited the hypotension to injections of PAF as well as the circulatory failure elicited by lipopolysaccharides (10 mg kg-1, i.v.). 3. LTA caused an increase in plasma concentration of creatinine from 39 +/- 5 microM (sham-operated) to 70 +/- 8 microM and urea from 4.7 +/- 0.1 to 13.1 +/- 1.6 mM. The renal failure elicited by LTA was significantly inhibited by WEB2086 (creatinine: 45 +/- 4 microM and urea: 5.7 +/- 0.7 mM), but not by BN52021. 4. The induction of nitric oxide synthase activity in lungs by LTA was attenuated by WEB2086 from 98 +/- 17 to 40 +/- 15 pmol L-citrulline 30 min-1 mg-1 protein (P < 0.01), but not by BN52021 (148 +/- 21 pmol L-citrulline 30 min-1 mg-1 protein). Similarly, WEB2086, but not BN52021, inhibited the increase in plasma nitrite concentration associated with the delayed circulatory failure caused by LTA. The release of tumour necrosis factor-alpha (TNF-alpha) after injection of LTA was not attenuated by WEB2086. 5. The induction of nitrite release by cultured macrophages activated with LTA (10 micrograms ml-1 for 24 h) was inhibited by 74 +/- 4% by WEB2086 (3 x 10(-4) M), but not by BN52021, indicating that only WEB2086 acts on intracellular PAF receptors. 6. Thus, the intracellular release of PAF contributes to the circulatory and renal failure and induction of nitric oxide synthase elicited by LTA in anaesthetized rats. The difference between the two structurally different PAF antagonists in our septic shock models using either LTA or lipopolysaccharide (LPS), shows the importance of models for Gram-positive sepsis in the elucidation of the pathophysiology of septic shock and for the evaluation of potential drugs.

De Kimpe, S. J.; Thiemermann, C.; Vane, J. R.

1995-01-01

310

CD66b overexpression and homotypic aggregation of human peripheral blood neutrophils after activation by a gram-positive stimulus.  

PubMed

Neutrophils represent the main component of innate immunity in the clearance of bacterial infections. To pass the tissue and to localize and reach the site of infection, the peripheral blood neutrophils have to pass through a complex receptor-mediated interaction with the endothelial layer. Under pathophysiological conditions, such as severe sepsis, this process is impaired and often characterized by neutrophil aggregation. In this study, we examined the impact of three different Staphylococcus aureus strains on the activation status of human peripheral blood neutrophils by coincubation of bacterial culture supernatant with whole blood. This complex interaction of a gram-positive stimulus with blood components leads to a special neutrophil activation phenotype, which is characterized by an overexpression of the cell-surface molecule CD66b. The process is accompanied by a strong increase of homotypic aggregates and seems to be initialized by a massive activation impulse caused by the interplay of plasma components. This maximum activation of neutrophils prior to the complex and highly regulated activation required for transmigration might play a key role in the neutrophil dysfunction in gram-positive sepsis. PMID:22319104

Schmidt, Thomas; Zündorf, Josef; Grüger, Thomas; Brandenburg, Kerstin; Reiners, Ana-Lena; Zinserling, Jörg; Schnitzler, Norbert

2012-02-08

311

Performances of VITEK 2 Colorimetric Cards for Identification of Gram-Positive and Gram-Negative Bacteria  

PubMed Central

Thepurpose of this study was to evaluate the new VITEK 2 identification cards that use colorimetric reading to identify gram-positive and gram-negative bacteria (GP and GN cards, respectively) in comparison to fluorimetric cards (ID-GPC and ID-GNB, respectively). A total of 580 clinical isolates and stock collection strains belonging to 116 taxa were included in the study. Of the 249 gram-positive strains tested with both the ID-GPC and GP cards, 218 (87.5%) and 235 (94.4%) strains were correctly identified (to the genus and species level), respectively. Of the 331 gram-negative strains tested with the ID-GNB and GN cards, 295 (89.1%) and 321 (97%) strains were correctly identified, respectively. Another focus of the study was to apply the percentages of correct identifications obtained in this study to the list of bacteria isolated in our laboratory (32,739 isolates) in the year 2004. We obtained 97.9% correct identifications with the colorimetric cards and 93.9% with fluorescent cards.

Wallet, Frederic; Loiez, Caroline; Renaux, Emilie; Lemaitre, Nadine; Courcol, Rene J.

2005-01-01

312

In vitro activity of the tribactam GV104326 against gram-positive, gram-negative, and anaerobic bacteria.  

PubMed Central

GV104326 is the first member of a new class of antibiotics (tribactams) selected for development. It combines a particularly broad spectrum (including gram-negative and gram-positive aerobes and anaerobes) with high potency, resistance to beta-lactamases, and complete stability to dehydropeptidases. Comparative MICs were determined for GV104326 against 415 recent clinical isolates (including beta-lactamase producers), using representative antibacterial agents (imipenem, amoxicillin-clavulanic acid, cefpirome, ciprofloxacin, gentamicin, and erythromycin). GV104326 was particularly active against gram-positive bacteria; in general, its in vitro activity was equivalent to that of imipenem, equivalent to or better than that of amoxicillin-clavulanic acid, and superior to that of cefpirome, ciprofloxacin, and erythromycin. Against gram-negative bacteria, GV104326 possessed activity similar to that of imipenem and cefpirome against enterobacteria and Haemophilus spp. but its activity was superior to that of amoxicillin-clavulanic acid. GV104326 showed excellent antianaerobe activity. GV104326 was stable to all clinically relevant beta-lactamases and was rapidly lethal to susceptible bacteria. In Escherichia coli, GV104326 bound predominantly to PBPs 1a and 2 and at low concentrations osmotically stable round forms were observed. GV104326 showed an affinity for PBPs 2 and 4 of Staphylococcus aureus.

Di Modugno, E; Erbetti, I; Ferrari, L; Galassi, G; Hammond, S M; Xerri, L

1994-01-01

313

In vitro antibacterial activities of PD 138312 and PD 140248, new fluoronaphthyridines with outstanding gram-positive potency.  

PubMed Central

PD 138312 and PD 140248 are new quinolones with high in vitro activities against a wide spectrum of bacterial species, notably including gram-positive isolates. The respective MICs (in micrograms per milliliter) of PD 138312 and PD 140248 capable of inhibiting > or = 90% of the strains were < or = 0.06 and < or = 0.06 for oxacillin-susceptible and -resistant staphylococci, streptococci (including Streptococcus pyogenes, S. agalactiae, S. pneumoniae, and viridans group streptococci), Haemophilus influenzae, Moraxella catarrhalis, and Neisseria gonorrhoeae; 0.125 and 0.03 for Legionella pneumophila; 0.25 and 0.125 for Listeria monocytogenes; 0.25 and 0.25 for Enterococcus faecalis; 0.5 and 0.06 for anaerobic gram-positive cocci; 0.5 and 0.25 for Acinetobacter spp.; 0.5 and 0.5 for members of the family Enterobacteriaceae (excluding Serratia marcescens); 2 and 0.5 for Bacteroides fragilis; 2 and 2 for Serratia marcescens and ciprofloxacin-resistant staphylococci; and 8 and 4 for Pseudomonas aeruginosa.

Huband, M D; Cohen, M A; Meservey, M A; Roland, G E; Yoder, S L; Dazer, M E; Domagala, J M

1993-01-01

314

A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria.  

PubMed

The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria. PMID:23771138

Quiles-Puchalt, Nuria; Tormo-Más, María Ángeles; Campoy, Susana; Toledo-Arana, Alejandro; Monedero, Vicente; Lasa, Iñigo; Novick, Richard P; Christie, Gail E; Penadés, José R

2013-06-14

315

A super-family of transcriptional activators regulates bacteriophage packaging and lysis in Gram-positive bacteria  

PubMed Central

The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria.

Quiles-Puchalt, Nuria; Tormo-Mas, Maria Angeles; Campoy, Susana; Toledo-Arana, Alejandro; Monedero, Vicente; Lasa, Inigo; Novick, Richard P.; Christie, Gail E.; Penades, Jose R.

2013-01-01

316

Targeting agr- and agr-Like quorum sensing systems for development of common therapeutics to treat multiple gram-positive bacterial infections.  

PubMed

Invasive infection by the Gram-positive pathogen Staphylococcus aureus is controlled by a four gene operon, agr that encodes a quorum sensing system for the regulation of virulence. While agr has been well studied in S. aureus, the contribution of agr homologues and analogues in other Gram-positive pathogens is just beginning to be understood. Intriguingly, other significant human pathogens, including Clostridium perfringens, Listeria monocytogenes, and Enterococcus faecalis contain agr or analogues linked to virulence. Moreover, other significant human Gram-positive pathogens use peptide based quorum sensing systems to establish or maintain infection. The potential for commonality in aspects of these signaling systems across different species raises the prospect of identifying therapeutics that could target multiple pathogens. Here, we review the status of research into these agr homologues, analogues, and other peptide based quorum sensing systems in Gram-positive pathogens as well as the potential for identifying common pathways and signaling mechanisms for therapeutic discovery. PMID:23598501

Gray, Brian; Hall, Pamela; Gresham, Hattie

2013-04-18

317

Production of a bacteriocin by a poultry derived Campylobacter jejuni isolate with antimicrobial activity against Clostridium perfringens and other Gram positive bacteria.  

Technology Transfer Automated Retrieval System (TEKTRAN)

We have purified a bacteriocin peptide (termed CUV-3), produced by a poultry cecal isolate of Campylobacter jejuni (strain CUV-3) with inhibitory activity against Gram positive bacteria including Clostridium perfringens (38 strains), Staphylococcus aureus, Staphylococcus epidermidis and Listeria mon...

318

In vitro susceptibilities of aerobic and facultative non-spore-forming gram-positive bacilli to HMR 3647 (RU 66647) and 14 other antimicrobials.  

PubMed

The comparative in vitro activity of the ketolide HMR 3647 (RU 66647) and those of structurally related macrolide-lincosamide-streptogramin compounds (erythromycin, roxithromycin, azithromycin, clarithromycin, josamycin, lincomycin, pristinamycin, and quinupristin-dalfopristin) as well as those of benzylpenicillin, doxycycline, vancomycin, teicoplanin, levofloxacin, and rifapentine against 247 aerobic and facultative non-spore-forming gram-positive bacilli were determined by an agar dilution method. The ketolide was active against most organisms tested except Corynebacterium striatum, coryneform CDC group 12, and Oerskovia spp. The frequency of resistance to erythromycin and other macrolides as well as that to lincomycin was high. Pristinamycin and, to a lesser extent, quinupristin-dalfopristin were very active, but resistance to these agents was present in some strains of Rhodococcus equi, Listeria spp., C. striatum, Erysipelothrix rhusiopathiae, and Oerskovia spp. HMR 3647 was very active against all erythromycin-sensitive and many erythromycin-nonsusceptible strains, especially Corynebacterium minutissimum, Corynebacterium pseudodiphtheriticum, Corynebacterium amycolatum, and Corynebacterium jeikeium. In vitro resistance to benzylpenicillin was common, but doxycycline, vancomycin, and teicoplanin were very active against most organisms tested except E. rhusiopathiae, against which glycopeptide antibiotics were not active. The in vitro activity of levofloxacin was remarkable, but resistance to this agent was common for C. amycolatum, Corynebacterium urealyticum, C. jeikeium, and Oerskovia spp. strains. Rifapentine was also very active in vitro against many organisms, but resistance to this agent was always present in E. rhusiopathiae and was very common in C. striatum and C. urealyticum. PMID:9593121

Soriano, F; Fernández-Roblas, R; Calvo, R; García-Calvo, G

1998-05-01

319

In Vitro Susceptibilities of Aerobic and Facultative Non-Spore-Forming Gram-Positive Bacilli to HMR 3647 (RU 66647) and 14 Other Antimicrobials  

PubMed Central

The comparative in vitro activity of the ketolide HMR 3647 (RU 66647) and those of structurally related macrolide-lincosamide-streptogramin compounds (erythromycin, roxithromycin, azithromycin, clarithromycin, josamycin, lincomycin, pristinamycin, and quinupristin-dalfopristin) as well as those of benzylpenicillin, doxycycline, vancomycin, teicoplanin, levofloxacin, and rifapentine against 247 aerobic and facultative non-spore-forming gram-positive bacilli were determined by an agar dilution method. The ketolide was active against most organisms tested except Corynebacterium striatum, coryneform CDC group I2, and Oerskovia spp. The frequency of resistance to erythromycin and other macrolides as well as that to lincomycin was high. Pristinamycin and, to a lesser extent, quinupristin-dalfopristin were very active, but resistance to these agents was present in some strains of Rhodococcus equi, Listeria spp., C. striatum, Erysipelothrix rhusiopathiae, and Oerskovia spp. HMR 3647 was very active against all erythromycin-sensitive and many erythromycin-nonsusceptible strains, especially Corynebacterium minutissimum, Corynebacterium pseudodiphtheriticum, Corynebacterium amycolatum, and Corynebacterium jeikeium. In vitro resistance to benzylpenicillin was common, but doxycycline, vancomycin, and teicoplanin were very active against most organisms tested except E. rhusiopathiae, against which glycopeptide antibiotics were not active. The in vitro activity of levofloxacin was remarkable, but resistance to this agent was common for C. amycolatum, Corynebacterium urealyticum, C. jeikeium, and Oerskovia spp. strains. Rifapentine was also very active in vitro against many organisms, but resistance to this agent was always present in E. rhusiopathiae and was very common in C. striatum and C. urealyticum.

Soriano, Francisco; Fernandez-Roblas, Ricardo; Calvo, Raquel; Garcia-Calvo, Gloria

1998-01-01

320

Antimicrobial activity of gatifloxacin tested against 1676 strains of ciprofloxacin-resistant Gram-positive cocci isolated from patient infections in North and South America  

Microsoft Academic Search

Gatifloxacin (formerly AM-115) is a new 8-methoxy fluoroquinolone with an expanded spectrum against Gram-positive cocci and some anaerobes. To assess this new agent’s activity, a collection of 1,676 Gram-positive cocci were selected for resistance to ciprofloxacin (?4 ?g\\/mL) and tested against gatifloxacin and 18 other compounds by reference broth microdilution methods. The strains (approximately 23,000 total isolates from the SENTRY

Ronald N Jones; Mondell L Beach; Michael A Pfaller; Gary V Doern

1998-01-01

321

Performance of the New VITEK 2 GP Card for Identification of Medically Relevant Gram-Positive Cocci in a Routine Clinical Laboratory  

Microsoft Academic Search

The VITEK 2 gram-positive (GP) identification card (bioMerieux, Marcy l'Etoile, France) has been rede- signed to achieve greater accuracy in the identification of gram-positive cocci. A total of 43 biochemical tests, including 17 enzymatic tests, are present in the card and interpreted in a kinetic mode, for up to 8 h. The VITEK 2 database, used in conjunction with the

Guido Funke; Pascale Funke-Kissling

322

Green fluorescent protein-labeled monitoring tool to quantify conjugative plasmid transfer between Gram-positive and Gram-negative bacteria.  

PubMed

On the basis of pIP501, a green fluorescent protein (GFP)-tagged monitoring tool was constructed for quantifying plasmid mobilization among Gram-positive bacteria and between Gram-positive Enterococcus faecalis and Gram-negative Escherichia coli. Furthermore, retromobilization of the GFP-tagged monitoring tool was shown from E. faecalis OG1X into the clinical isolate E. faecalis T9. PMID:22138997

Arends, Karsten; Schiwon, Katarzyna; Sakinc, Türkan; Hübner, Johannes; Grohmann, Elisabeth

2011-12-02

323

Green Fluorescent Protein-Labeled Monitoring Tool To Quantify Conjugative Plasmid Transfer between Gram-Positive and Gram-Negative Bacteria  

PubMed Central

On the basis of pIP501, a green fluorescent protein (GFP)-tagged monitoring tool was constructed for quantifying plasmid mobilization among Gram-positive bacteria and between Gram-positive Enterococcus faecalis and Gram-negative Escherichia coli. Furthermore, retromobilization of the GFP-tagged monitoring tool was shown from E. faecalis OG1X into the clinical isolate E. faecalis T9.

Arends, Karsten; Schiwon, Katarzyna; Sakinc, Turkan; Hubner, Johannes

2012-01-01

324

In vitro antimicrobial activity of GAR936 tested against antibiotic-resistant gram-positive blood stream infection isolates and strains producing extended-spectrum ?-lactamases  

Microsoft Academic Search

GAR-936, a new, semisynthetic glycylcycline, has shown good antibacterial activity against a wide range of clinically important Gram-positive and –negative aerobic bacteria including Streptococcus pneumoniae,Hemophilus influenzae,Moraxella catarrhalis,Neisseria gonorrhoeae, most Enterobacteriaceae, Staphylococcus aureus and Enterococcus spp. The purpose of this study was to determine the activity of GAR-936 against a range of Gram-positive and –negative bloodstream isolates including many strains producing

Douglas J Biedenbach; Mondell L Beach; Ronald N Jones

2001-01-01

325

Comparison of the immunostimulatory and proinflammatory activities of candidate Gram-positive endotoxins, lipoteichoic acid, peptidoglycan, and lipopeptides, in murine and human cells  

Microsoft Academic Search

The role of lipopolysaccharide (LPS) in the pathogenesis of Gram-negative septic shock is well established. The corresponding proinflammatory and immunostimulatory molecule(s) on the Gram-positive bacteria is less well understood, and its identification and characterization would be a key prerequisite in designing specific sequestrants of the Gram-positive endotoxin(s). We report in this paper the comparison of NF-?B-, cytokine- and chemokine-inducing activities

Matthew R. Kimbrell; Hemamali Warshakoon; Jens R. Cromer; Subbalakshmi Malladi; Jennifer D. Hood; Rajalakshmi Balakrishna; Tandace A. Scholdberg; Sunil A. David

2008-01-01

326

Assessment of the in vitro Efficacy of the Novel Antimicrobial Peptide CECT7121 against Human Gram-Positive Bacteria from Serious Infections Refractory to Treatment  

Microsoft Academic Search

Background: Resistant Gram-positive bacteria are causing increasing concern in clinical practice. This work investigated theefficacy of AP-CECT7121 (an antimicrobial peptide isolated from an environmental strain of Enterococcus faecalis CECT7121) against various pathogenic Gram-positive bacteria. Methods: Strains were isolated from intensive care unit patients unresponsive to standard antibiotic treatments. Inhibitory activity of AP-CECT7121 was assessed using the agar-well diffusion method. The

M. D. Sparo; D. G. Jones; S. F. Sánchez Bruni

2009-01-01

327

Kineococcus radiotolerans sp. nov., a radiation-resistant, gram-positive bacterium.  

PubMed

A gram-type positive, motile, coccus-shaped organism was isolated from a radioactive work area. Strain SRS30216T is an orange-pigmented bacterium that is catalase-positive, oxidase-negative and urease-negative. The orange pigment is most likely a carotenoid with absorption peaks at approximately 444, 471 and 501 nm. Cells normally grew in clusters, but individual, motile, flagellated cells were also observed. Growth of strain SRS30216T occurred at temperatures between 11 and 41 degrees C, between pH 5 and 9 and at NaCl concentrations up to and including 5%. Fatty acid composition was limited, with >90% of the fatty acids being anteiso 15:0. Alkenes of 19-24 carbons in length were detected during examination of the neutral lipids. Strain SRS30216T demonstrated high levels of resistance to gamma-radiation and desiccation. The most closely related recognized species is Kineococcus aurantiacus RA 333T, which is 93% similar in 16S rDNA sequence. DNA-DNA hybridization revealed only 31% similarity between these two organisms. It is proposed that SRS30216T (= ATCC BAA-149T = DSM 14245T) represents the type strain of a novel species in the genus Kineococcus, Kineococcus radiotolerans sp. nov.. PMID:12054260

Phillips, Robert W; Wiegel, Juergen; Berry, Christopher J; Fliermans, Carl; Peacock, Aaron D; White, David C; Shimkets, Lawrence J

2002-05-01

328

Bioreduction of Cr(VI) by alkaliphilic Bacillus subtilis and interaction of the membrane groups  

PubMed Central

Detoxification of Cr(VI) under alkaline pH requires attention due to the alkaline nature of many effluents. An alkaliphilic gram-positive Bacillus subtilis isolated from tannery effluent contaminated soil was found to grow and reduce Cr(VI) up to 100% at an alkaline pH 9. Decrease in pH to acidic range with growth of the bacterium signified the role played by metabolites (organic acids) in chromium resistance and reduction mechanism. The XPS and FT-IR spectra confirmed the reduction of Cr(VI) by bacteria into +3 oxidation state. Chromate reductase assay indicated that the reduction was mediated by constitutive membrane bound enzymes. The kinetics of Cr(VI) reduction activity derived using the monod equation proved (Ks = 0.00032) high affinity of the organism to the metal. This study thus helped to localize the reduction activity at subcellular level in a chromium resistant alkaliphilic Bacillus sp.

Mary Mangaiyarkarasi, M.S.; Vincent, S.; Janarthanan, S.; Subba Rao, T.; Tata, B.V.R.

2010-01-01

329

Plants used in Guatemala for the treatment of respiratory diseases. 1. Screening of 68 plants against gram-positive bacteria.  

PubMed

Respiratory ailments are important causes of morbidity and mortality in developing countries. Ethnobotanical surveys and literature reviews conducted in Guatemala during 1986-88 showed that 234 plants from 75 families, most of them of American origin, have been used for the treatment of respiratory ailments. Three Gram-positive bacteria causing respiratory infections (Staphylococcus aureus, Streptococcus pneumoniae and Streptococcus pyogenes) were used to screen 68 of the most commonly used plants for activity. Twenty-eight of these (41.2%) inhibited the growth of one or more of the bacteria tested. Staphylococcus aureus was inhibited by 18 of the plant extracts, while 7 extracts were effective against Streptococcus pyogenes. Plants of American origin which exhibited antibacterial activity were: Gnaphalium viscosum, Lippia alba, Lippia dulcis, Physalis philadelphica, Satureja brownei, Solanum nigrescens and Tagetes lucida. These preliminary in vitro results provide scientific basis for the use of these plants against bacterial respiratory infections. PMID:2023428

Caceres, A; Alvarez, A V; Ovando, A E; Samayoa, B E

1991-02-01

330

Functioning of the TA cassette of streptococcal plasmid pSM19035 in various Gram-positive bacteria.  

PubMed

Toxin-antitoxin (TA) systems are common in microorganisms and are frequently found in the chromosomes and low-copy number plasmids of bacterial pathogens. One such system is carried by the low copy number plasmid pSM19035 of the pathogenic bacterium Streptococcus pyogenes. This plasmid encodes an omega-epsilon-zeta cassette that ensures its stable maintenance by post-segregational killing of plasmid-free cells. In this study, the activity of the ?-?-? cassette was examined in various Gram-positive bacteria with a low G/C content in their DNA. The broad host range of pSM19035 was confirmed and the copy number of a truncated derivative in transformed strains was determined by real-time qPCR. PMID:22309878

Brzozowska, Iwona; Brzozowska, Kinga; Zielenkiewicz, Urszula

2012-01-31

331

Synergistic effect of clinically used antibiotics and peptide antibiotics against Gram-positive and Gram-negative bacteria  

PubMed Central

Ribosomally synthesized (natural) peptides demonstrate antimicrobial potency and may represent a novel therapeutic approach for the treatment of infections. The aim of the present study was to investigate the interaction between polycationic peptides and clinically used antimicrobial agents in the treatment of clinical isolates of Gram-positive and Gram-negative aerobic bacteria in vitro, using the microbroth dilution method. The combination studies demonstrated synergies between ranalexin and polymyxin E, doxycycline and clarithromycin. Similarly, magainin II was demonstrated to be synergistic with ceftriaxone, amoxicillin clavulanate, ceftazidime, meropenem, piperacillin and ?-lactam antibiotics. Buforin II, cecropin P1 and indolicidin were not observed to be synergistic with the clinically used antibiotics, but demonstrated additive effects with them. Notably, no antagonistic effects were identified in all the combinations examined.

ZHOU, YULING; PENG, YAN

2013-01-01

332

Amplifiable DNA from Gram-negative and Gram-positive bacteria by a low strength pulsed electric field method  

PubMed Central

An efficient electric field-based procedure for cell disruption and DNA isolation is described. Isoosmotic suspensions of Gram-negative and Gram-positive bacteria were treated with pulsed electric fields of <60 V/cm. Pulses had an exponential decay waveform with a time constant of 3.4 µs. DNA yield was linearly dependent on time or pulse number, with several thousand pulses needed. Electrochemical side-effects and electrophoresis were minimal. The lysates contained non-fragmented DNA which was readily amplifiable by PCR. As the method was not limited to samples of high specific resistance, it should be applicable to physiological fluids and be useful for genomic and DNA diagnostic applications.

Vitzthum, Frank; Geiger, Georg; Bisswanger, Hans; Elkine, Bentsian; Brunner, Herwig; Bernhagen, Jurgen

2000-01-01

333

Antimicrobial Growth Promoters Used in Animal Feed: Effects of Less Well Known Antibiotics on Gram-Positive Bacteria  

PubMed Central

There are not many data available on antibiotics used solely in animals and almost exclusively for growth promotion. These products include bambermycin, avilamycin, efrotomycin, and the ionophore antibiotics (monensin, salinomycin, narasin, and lasalocid). Information is also scarce for bacitracin used only marginally in human and veterinary medicine and for streptogramin antibiotics. The mechanisms of action of and resistance mechanisms against these antibiotics are described. Special emphasis is given to the prevalence of resistance among gram-positive bacteria isolated from animals and humans. Since no susceptibility breakpoints are available for most of the antibiotics discussed, an alternative approach to the interpretation of MICs is presented. Also, some pharmacokinetic data and information on the influence of these products on the intestinal flora are presented.

Butaye, Patrick; Devriese, Luc A.; Haesebrouck, Freddy

2003-01-01

334

Modes of phagocytosis of Gram-positive and Gram-negative bacteria by Spodoptera littoralis granular haemocytes.  

PubMed

Haemocytes are the main immunocompetent cells in insect cellular immune reactions. Here, we show that in Spodoptera littoralis, granular haemocytes are the primary phagocyte haemocytes, both in vivo and in vitro. The "trigger" and "zipper" modes of engulfment known in mammal macrophages are active, in vivo, in S. littoralis granular haemocytes, together with macropinocytosis. Lipopolysaccharide as well as lipoteichoic acid inhibit the binding of both Gram-positive (Corynebacterium xerosis) and Gram-negative (Escherichia coli) bacteria on granular haemocytes. In addition, different ligands can inhibit the binding of E. coli. Most of these inhibitors are known as ligands of scavenger receptors in mammal macrophages and we hypothesise that one of the receptors present on S. littoralis granular haemocytes could be a scavenger-like receptor. PMID:15686644

Costa, Sónia C P; Ribeiro, Carlos; Girard, Pierre-Alain; Zumbihl, Robert; Brehélin, Michel

2005-01-01

335

Activities of the semisynthetic glycopeptide LY191145 against vancomycin-resistant enterococci and other gram-positive bacteria.  

PubMed Central

LY191145 is the prototype of a series of compounds with activities against vancomycin-resistant enterococci derived by modification of the glycopeptide antibiotic LY264826. LY191145 had MICs for vancomycin- and teicoplanin-resistant enterococci of < or = 4 micrograms/ml for 50% of isolates and < or = 16 micrograms/ml for 90% of isolates. Its MICs for vancomycin-resistant, teicoplanin-susceptible enterococci were 1 to 8 micrograms/ml. LY191145 retains the potent activities of its parent compound against staphylococci and streptococci. In vivo studies in a mouse infection model confirmed these activities. This compound indicates the potential of semisynthetic glycopeptides as agents against antibiotic-resistant gram-positive bacteria.

Nicas, T I; Mullen, D L; Flokowitsch, J E; Preston, D A; Snyder, N J; Stratford, R E; Cooper, R D

1995-01-01

336

Bacillus anthracis genome organization in light of whole transcriptome sequencing  

SciTech Connect

Emerging knowledge of whole prokaryotic transcriptomes could validate a number of theoretical concepts introduced in the early days of genomics. What are the rules connecting gene expression levels with sequence determinants such as quantitative scores of promoters and terminators? Are translation efficiency measures, e.g. codon adaptation index and RBS score related to gene expression? We used the whole transcriptome shotgun sequencing of a bacterial pathogen Bacillus anthracis to assess correlation of gene expression level with promoter, terminator and RBS scores, codon adaptation index, as well as with a new measure of gene translational efficiency, average translation speed. We compared computational predictions of operon topologies with the transcript borders inferred from RNA-Seq reads. Transcriptome mapping may also improve existing gene annotation. Upon assessment of accuracy of current annotation of protein-coding genes in the B. anthracis genome we have shown that the transcriptome data indicate existence of more than a hundred genes missing in the annotation though predicted by an ab initio gene finder. Interestingly, we observed that many pseudogenes possess not only a sequence with detectable coding potential but also promoters that maintain transcriptional activity.

Martin, Jeffrey; Zhu, Wenhan; Passalacqua, Karla D.; Bergman, Nicholas; Borodovsky, Mark

2010-03-22

337

Differential mode of antimicrobial actions of arginine-rich and lysine-rich histones against Gram-positive Staphylococcus aureus.  

PubMed

We previously reported the activities and modes of action of arginine (Arg)-rich histones H3 and H4 against Gram-negative bacteria. In the present study, we investigated the properties of the Arg-rich histones against Gram-positive bacteria in comparison with those of lysine (Lys)-rich histone H2B. In a standard microdilution assay, calf thymus histones H2B, H3, and H4 showed growth inhibitory activity against Staphylococcus aureus with minimum effective concentration values of 4.0, 4.0, and 5.6?M, respectively. Laser confocal microscopic analyses revealed that both the Arg-rich and Lys-rich histones associated with the surface of S. aureus. However, while the morphology of S. aureus treated with histone H2B appeared intact, those treated with the histones H3 and H4 closely resembled each other, and the cells were blurred. Electrophoretic mobility shift assay results revealed these histones have binding affinity to lipoteichoic acid (LTA), one of major cell surface components of Gram-positive bacteria. Scanning electron microscopic analyses demonstrated that while histone H2B elicited no obvious changes in cell morphology, histones H3 and H4 disrupted the cell membrane structure with bleb formation in a manner similar to general antimicrobial peptides. Consequently, our results suggest that bacterial cell surface LTA initially attracts both the Arg- and Lys-rich histones, but the modes of antimicrobial action of these histones are different; the former involves cell membrane disruption and the latter involves the cell integrity disruption. PMID:23932939

Morita, Shuu; Tagai, Chihiro; Shiraishi, Takayuki; Miyaji, Kazuyuki; Iwamuro, Shawichi

2013-08-08

338

Sortase activity is controlled by a flexible lid in the pilus biogenesis mechanism of gram-positive pathogens.  

PubMed

Pili are surface-linked virulence factors that play key roles in infection establishment in a variety of pathogenic species. In Gram-positive pathogens, pilus formation requires the action of sortases, dedicated transpeptidases that covalently associate pilus building blocks. In Streptococcus pneumoniae, a major human pathogen, all genes required for pilus formation are harbored in a single pathogenicity islet which encodes three structural proteins (RrgA, RrgB, RrgC) and three sortases (SrtC-1, SrtC-2, SrtC-3). RrgB forms the backbone of the streptococcal pilus, to which minor pilins RrgA and RrgC are covalently associated. SrtC-1 is the main sortase involved in polymerization of the RrgB fiber and displays a lid which encapsulates the active site, a feature present in all pilus-related sortases. In this work, we show that catalysis by SrtC-1 proceeds through a catalytic triad constituted of His, Arg, and Cys and that lid instability affects protein fold and catalysis. In addition, we show by thermal shift analysis that lid flexibility can be stabilized by the addition of substrate-like peptides, a feature shared by other periplasmic transpeptidases. We also report the characterization of a trapped acyl-enzyme intermediate formed between SrtC-1 and RrgB. The presence of lid-encapsulated sortases in the pilus biogenesis systems in many Gram-positive pathogens points to a common mechanism of substrate recognition and catalysis that should be taken into consideration in the development of sortase inhibitors. PMID:19810750

Manzano, Clothilde; Izoré, Thierry; Job, Viviana; Di Guilmi, Anne Marie; Dessen, Andréa

2009-11-10

339

Antimicrobial activity of daptomycin tested against Gram-positive pathogens collected in Europe, Latin America, and selected countries in the Asia-Pacific Region (2011).  

PubMed

We report the results of the international daptomycin surveillance programs for Europe, Latin America, and selected Asia-Pacific nations. A total of 7948 consecutive Gram-positive organisms of clinical significance were collected in 2011 and susceptibility tested against daptomycin and various comparator agents by Clinical and Laboratory Standards Institute (Clinical and Laboratory Standards Institute. M07-A9. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically; approved standard: ninth edition Wayne, PA: CLSI. 2012.; Cubicin Package Insert 2012. Cubist Pharmaceuticals, Inc, Lexington, MA. Available at http://www.cubicin.com/pdf/PrescribingInformation.pdf. Accessed January 1, 2012.) broth microdilution methods. The test medium was adjusted to contain physiological levels of calcium (50 mg/L) when testing daptomycin. Daptomycin exhibited potent activity against methicillin-susceptible and -resistant Staphylococcus aureus overall and for each region (MIC(50/90), 0.25-0.5/0.5 ?g/mL), with susceptibility rates at 100.0% in Latin America, Australia/New Zealand, and India, and at 99.9% in Europe. The daptomycin MIC(50/90) for coagulase-negative staphylococci was also at 0.25-0.5/0.5 ?g/mL, and only 1 isolate was considered nonsusceptible with a MIC value at 2 ?g/mL. Daptomycin was also highly active against Enterococcus faecalis (MIC(50/90), 1/1-2 ?g/mL) and E. faecium (MIC(50/90), 2/2 ?g/mL for both vancomycin-susceptible and -resistant isolates). All enterococcal isolates were susceptible to daptomycin (MIC, ?4 ?g/mL) and tigecycline. Susceptibility to linezolid for E. faecalis was at 100.0%, while for E. faecium regional susceptibility rates were at 100.0% except in Europe (99.0%). Viridans group streptococci (MIC(50/90), 0.25/1 ?g/mL) and ?-haemolytic streptococci (MIC(50/90), ?0.06/0.25 ?g/mL) continue to be very susceptible to daptomycin. In summary, the results of this investigation document the high potency and wide spectrum of daptomycin when tested against a large resistance-surveillance collection of Gram-positive pathogens and indicate that daptomycin nonsusceptibility remains rare among indicated species after many years of clinical use worldwide. PMID:23514757

Sader, Helio S; Flamm, Robert K; Jones, Ronald N

2013-04-01

340

In Vitro Activities of the New Semisynthetic Glycopeptide Telavancin (TD-6424), Vancomycin, Daptomycin, Linezolid, and Four Comparator Agents against Anaerobic Gram-Positive Species and Corynebacterium spp.  

PubMed Central

Telavancin is a new semisynthetic glycopeptide anti-infective with multiple mechanisms of action, including inhibition of bacterial membrane phospholipid synthesis and inhibition of bacterial cell wall synthesis. We determined the in vitro activities of telavancin, vancomycin, daptomycin, linezolid, quinupristin-dalfopristin, imipenem, piperacillin-tazobactam, and ampicillin against 268 clinical isolates of anaerobic gram-positive organisms and 31 Corynebacterium strains using agar dilution methods according to National Committee for Clinical Laboratory Standards procedures. Plates with daptomycin were supplemented with Ca2+ to 50 mg/liter. The MICs at which 90% of isolates tested were inhibited (MIC90s) for telavancin and vancomycin were as follows: Actinomyces spp. (n = 45), 0.25 and 1 ?g/ml, respectively; Clostridium difficile (n = 14), 0.25 and 1 ?g/ml, respectively; Clostridium ramosum (n = 16), 1 and 4 ?g/ml, respectively; Clostridium innocuum (n = 15), 4 and 16 ?g/ml, respectively; Clostridium clostridioforme (n = 15), 8 and 1 ?g/ml, respectively; Eubacterium group (n = 33), 0.25 and 2 ?g/ml, respectively; Lactobacillus spp. (n = 26), 0.5 and 4 ?g/ml, respectively; Propionibacterium spp. (n = 34), 0.125 and 0.5 ?g/ml, respectively; Peptostreptococcus spp. (n = 52), 0.125 and 0.5 ?g/ml, respectively; and Corynebacterium spp. (n = 31), 0.03 and 0.5 ?g/ml, respectively. The activity of TD-6424 was similar to that of quinupristin-dalfopristin for most strains except C. clostridioforme and Lactobacillus casei, where quinupristin-dalfopristin was three- to fivefold more active. Daptomycin had decreased activity (MIC > 4 ?g/ml) against 14 strains of Actinomyces spp. and all C. ramosum, Eubacterium lentum, and Lactobacillus plantarum strains. Linezolid showed decreased activity (MIC > 4 ?g/ml) against C. ramosum, two strains of C. difficile, and 15 strains of Lactobacillus spp. Imipenem and piperacillin-tazobactam were active against >98% of strains. The MICs of ampicillin for eight Clostridium spp. and three strains of L. casei were >1 ?g/ml. The MIC90 of TD-6424 for all strains tested was ?2 ?g/ml. TD-6424 has potential for use against infections with gram-positive anaerobes and deserves further clinical evaluation.

Goldstein, Ellie J. C.; Citron, Diane M.; Merriam, C. Vreni; Warren, Yumi A.; Tyrrell, Kerin L.; Fernandez, Helen T.

2004-01-01

341

Bacillus bogoriensis sp. nov., a novel alkaliphilic, halotolerant bacterium isolated from a Kenyan soda lake.  

PubMed

Strain LBB3(T) isolated from Bogoria soda lake in Kenya is an alkaliphilic, Gram-positive, strictly aerobic, non-motile, spore-forming bacterium. It was identified as a member of the genus Bacillus on the basis of phenotypic and phylogenetic analyses. The organism grows optimally at 37 degrees C and pH 10. The G+C content of the genomic DNA is 37.5 mol%. 16S rRNA gene sequence analysis showed 95 and 96 % sequence similarity with Bacillus pseudofirmus (DSM 8715(T)) and Bacillus alcalophilus (DSM 485(T)), respectively. Furthermore, DNA-DNA hybridization against these two Bacillus species showed 39.0 and 55.5 % similarity, respectively. Based on our observations, strain LBB3(T) is proposed to represent a novel species of the genus Bacillus, for which the name Bacillus bogoriensis sp. nov. is proposed. The type strain of B. bogoriensis is LBB3(T) (=ATCC BAA-922(T)=LMG 22234(T)). PMID:15774682

Vargas, Virginia A; Delgado, Osvaldo D; Hatti-Kaul, Rajni; Mattiasson, Bo

2005-03-01

342

Differential sensitivity of aerobic gram-positive and gram-negative microorganisms to 2,4,6-trinitrotoluene (TNT) leads to dissimilar growth and TNT transformation: Results of soil and pure culture studies  

SciTech Connect

The effects of 2,4,6-trinitrotoluene (TNT) on indigenous soil populations and pure bacterial cultures were examined. The number of colony-forming units (CFU) appearing when TNT-contaminated soil was spread on 0.3% molasses plates decreased by 50% when the agar was amended with 67 {mu}g TNT mL{sup -1}, whereas a 99% reduction was observed when uncontaminated soil was plated. Furthermore, TNT-contaminated soil harbored a greater number of organisms able to grow on plates amended with greater than 10 {mu}g TNT mL{sup -1}. The percentage of gram-positive isolates was markedly less in TNT-contaminated soil (7%; 2 of 30) than in uncontaminated soil (61%; 20 of 33). Pseudomonas aeruginosa, Pseudomonas corrugate, Pseudomonasfluorescens and Alcaligenes xylosoxidans made up the majority of the gram-negative isolates from TNT-contaminated soil. Gram-positive isolates from both soils demonstrated marked growth inhibition when greater than 8-16 {mu}g TNT mL{sup -1} was present in the culture media. Most pure cultures of known aerobic gram-negative organisms readily degraded TNT and evidenced net consumption of reduced metabolites. However, pure cultures of aerobic gram-positive bacteria were sensitive to relatively low concentrations of TNT as indicated by the 50% reduction in growth and TNT transformation which was observed at approximately 10 {mu}g TNT mL{sup -1}. Most non-sporeforming gram-positive organisms incubated in molasses media amended with 80 {mu}g TNT mL{sup -1} or greater became unculturable, whereas all strains tested remained culturable when incubated in mineral media amended with 98 {mu}g TNT mL{sup -1}, indicating that TNT sensitivity is likely linked to cell growth. These results indicate that gram-negative organisms are most likely responsible for any TNT transformation in contaminated soil, due to their relative insensitivity to high TNT concentrations and their ability to transform TNT.

Fuller, M.E.; Manning, J.F. Jr.

1996-07-30

343

Impact of ferrihydrite and anthraquinone-2,6-disulfonate on the reductive transformation of 2,4,6-trinitrotoluene by a gram-positive fermenting bacterium.  

PubMed

Batch studies were conducted to explore differences in the transformation pathways of 2,4,6-trinitrotoluene (TNT) reduction by a Gram-positive fermenting bacterium (Cellulomonas sp. strain ES6) in the presence and absence of ferrihydrite and the electron shuttle anthraquinone-2,6-disulfonate (AQDS). Strain ES6 was capable of TNT and ferrihydrite reduction with increased reduction rates in the presence of AQDS. Hydroxylaminodinitrotoluenes, 2,4-dihydroxylamino-6-nitrotoluene (2,4-DHANT), and tetranitroazoxytoluenes were the major metabolites observed in ferrihydrite- and AQDS-free systems in the presence of pure cell cultures. Ferrihydrite enhanced the production of amino derivatives because of reactions with microbially produced surface-associated Fe(ll). The presence of AQDS in the absence of ferrihydrite promoted the fast initial formation of arylhydroxylamines such as 2,4-DHANT. However, unlike in pure cell systems, these arylhydroxylamines were transformed into several unidentified polar products. When both microbially reduced ferrihydrite and AQDS were present simultaneously, the reduction of TNT was more rapid and complete via pathways thatwould have been difficult to infer solely from single component studies. This study demonstrates the complexity of TNT degradation patterns in model systems where the interactions among bacteria, Fe minerals, and organic matter have a pronounced effect on the degradation pathway of TNT. PMID:16201638

Borch, Thomas; Inskeep, William P; Harwood, Jace A; Gerlach, Robin

2005-09-15

344

Complete genome sequence of the industrial bacterium Bacillus licheniformis and comparisons with closely related Bacillus species  

PubMed Central

Background Bacillus licheniformis is a Gram-positive, spore-forming soil bacterium that is used in the biotechnology industry to manufacture enzymes, antibiotics, biochemicals and consumer products. This species is closely related to the well studied model organism Bacillus subtilis, and produces an assortment of extracellular enzymes that may contribute to nutrient cycling in nature. Results We determined the complete nucleotide sequence of the B. licheniformis ATCC 14580 genome which comprises a circular chromosome of 4,222,336 base-pairs (bp) containing 4,208 predicted protein-coding genes with an average size of 873 bp, seven rRNA operons, and 72 tRNA genes. The B. licheniformis chromosome contains large regions that are colinear with the genomes of B. subtilis and Bacillus halodurans, and approximately 80% of the predicted B. licheniformis coding sequences have B. subtilis orthologs. Conclusions Despite the unmistakable organizational similarities between the B. licheniformis and B. subtilis genomes, there are notable differences in the numbers and locations of prophages, transposable elements and a number of extracellular enzymes and secondary metabolic pathway operons that distinguish these species. Differences include a region of more than 80 kilobases (kb) that comprises a cluster of polyketide synthase genes and a second operon of 38 kb encoding plipastatin synthase enzymes that are absent in the B. licheniformis genome. The availability of a completed genome sequence for B. licheniformis should facilitate the design and construction of improved industrial strains and allow for comparative genomics and evolutionary studies within this group of Bacillaceae.

Rey, Michael W; Ramaiya, Preethi; Nelson, Beth A; Brody-Karpin, Shari D; Zaretsky, Elizabeth J; Tang, Maria; de Leon, Alfredo Lopez; Xiang, Henry; Gusti, Veronica; Clausen, Ib Groth; Olsen, Peter B; Rasmussen, Michael D; Andersen, Jens T; J?rgensen, Per L; Larsen, Thomas S; Sorokin, Alexei; Bolotin, Alexander; Lapidus, Alla; Galleron, Nathalie; Ehrlich, S Dusko; Berka, Randy M

2004-01-01

345

Phenotypic and functional characterization of Bacillus anthracis biofilms.  

PubMed

Biofilms, communities of micro-organisms attached to a surface, are responsible for many chronic diseases and are often associated with environmental reservoirs or lifestyles. Bacillus anthracis is a Gram-positive, endospore-forming bacterium and is the aetiological agent of pulmonary, gastrointestinal and cutaneous anthrax. Anthrax infections are part of the natural lifecycle of many ruminants in North America, including cattle and bison, and B. anthracis is thought to be a central part of this ecosystem. However, in endemic areas in which humans and livestock interact, chronic cases of cutaneous anthrax are commonly reported. This suggests that biofilms of B. anthracis exist in the environment and are part of the ecology associated with its lifecycle. Currently, there are few data that account for the importance of the biofilm mode of life in B. anthracis, yet biofilms have been characterized in other pathogenic and non-pathogenic Bacillus species, including Bacillus cereus and Bacillus subtilis, respectively. This study investigated the phenotypic and functional role of biofilms in B. anthracis. The results demonstrate that B. anthracis readily forms biofilms which are inherently resistant to commonly prescribed antibiotics, and that antibiotic resistance is not solely the function of sporulation. PMID:17526827

Lee, Keehoon; Costerton, J W; Ravel, Jacques; Auerbach, Raymond K; Wagner, David M; Keim, Paul; Leid, Jeff G

2007-06-01

346

Evaluation of the Staphylococcus aureus class C nonspecific acid phosphatase (SapS) as a reporter for gene expression and protein secretion in gram-negative and gram-positive bacteria.  

PubMed

A phosphatase secreted by Staphylococcus aureus strain 154 has previously been characterized and classified as a new member of the bacterial class C family of nonspecific acid phosphatases. As the acid phosphatase activity can be easily detected with a cost-effective plate screen assay, quantitatively measured by a simple enzyme assay, and detected by zymography, its potential use as a reporter system was investigated. The S. aureus acid phosphatase (sapS) gene has been cloned and expressed from its own regulatory sequences in Escherichia coli, Bacillus subtilis, and Bacillus halodurans. Transcriptional and translational fusions of the sapS gene with selected heterologous promoters and signal sequences were constructed and expressed in all three of the host strains. From the range of promoters evaluated, the strongest promoter for heterologous protein production in each of the host strains was identified, i.e., the E. coli lacZ promoter in E. coli, the B. halodurans alkaline protease promoter in B. subtilis, and the B. halodurans sigma(D) promoter in B. halodurans. This is the first report on the development of a class C acid phosphatase gene as a reporter gene with the advantage of being able to function in both gram-positive and gram-negative host strains. PMID:17905879

du Plessis, Erika; Theron, Jacques; Berger, Eldie; Louw, Maureen

2007-09-28

347

Granular Layer in the Periplasmic Space of Gram-Positive Bacteria and Fine Structures of Enterococcus gallinarum and Streptococcus gordonii Septa Revealed by Cryo-Electron Microscopy of Vitreous Sections  

PubMed Central

High-resolution structural information on optimally preserved bacterial cells can be obtained with cryo-electron microscopy of vitreous sections. With the help of this technique, the existence of a periplasmic space between the plasma membrane and the thick peptidoglycan layer of the gram-positive bacteria Bacillus subtilis and Staphylococcus aureus was recently shown. This raises questions about the mode of polymerization of peptidoglycan. In the present study, we report the structure of the cell envelope of three gram-positive bacteria (B. subtilis, Streptococcus gordonii, and Enterococcus gallinarum). In the three cases, a previously undescribed granular layer adjacent to the plasma membrane is found in the periplasmic space. In order to better understand how nascent peptidoglycan is incorporated into the mature peptidoglycan, we investigated cellular regions known to represent the sites of cell wall production. Each of these sites possesses a specific structure. We propose a hypothetic model of peptidoglycan polymerization that accommodates these differences: peptidoglycan precursors could be exported from the cytoplasm to the periplasmic space, where they could diffuse until they would interact with the interface between the granular layer and the thick peptidoglycan layer. They could then polymerize with mature peptidoglycan. We report cytoplasmic structures at the E. gallinarum septum that could be interpreted as cytoskeletal elements driving cell division (FtsZ ring). Although immunoelectron microscopy and fluorescence microscopy studies have demonstrated the septal and cytoplasmic localization of FtsZ, direct visualization of in situ FtsZ filaments has not been obtained in any electron microscopy study of fixed and dehydrated bacteria.

Zuber, Benoit; Haenni, Marisa; Ribeiro, Tania; Minnig, Kathrin; Lopes, Fatima; Moreillon, Philippe; Dubochet, Jacques

2006-01-01

348

Two different primary oxidation mechanisms during biotransformation of thymol by gram-positive bacteria of the genera Nocardia and Mycobacterium.  

PubMed

Thymol has antibacterial, antifungal, insecticidal, and antioxidative properties which are the basis for the wide use of this compound in the cosmetic, food, and pharmaceutical industries. Although thymol is a ubiquitously occurring substance in the environment, data about its degradation and detoxification by bacteria are sparse. Here, we show the existence of two different pathways for the biotransformation of thymol by Nocardia cyriacigeorgica and Mycobacterium neoaurum which were described for the first time for gram-positive bacteria. The first pathway starts with hydroxylation of thymol to thymohydroquinone (2-isopropyl-5-methylbenzene-1,4-diol) with subsequent oxidation to thymobenzoquinone (2-isopropyl-5-methyl-1,4-benzoquinone). The second pathway involves hydroxylation of the methyl group followed by oxidation to 3-hydroxy-4-isopropylbenzoic acid, possibly via the aldehyde 3-hydroxy-4-isopropylbenzaldehyde. It is noteworthy that the branched side chain of thymol was not oxidized. Similarities and differences of these oxidation processes with those of the gram-negative bacterium Pseudomonas putida, fungi, and plants are discussed and, in addition, the toxicity of thymol towards N. cyriacigeorgica and M. neoaurum was tested. The experiments showed a temporary growth inhibition with 0.025 % thymol. This was explained by degradation of thymol and the formation of products which are less toxic than thymol itself. PMID:22828982

Hahn, Veronika; Sünwoldt, Katharina; Mikolasch, Annett; Schauer, Frieder

2012-07-25

349

Type IV pili-dependent gliding motility in the Gram-positive pathogen Clostridium perfringens and other Clostridia.  

PubMed

Bacteria can swim in liquid media by flagellar rotation and can move on surfaces via gliding or twitching motility. One type of gliding motility involves the extension, attachment and retraction of type IV pili (TFP), which pull the bacterium towards the site of attachment. TFP-dependent gliding motility has been seen in many Gram-negative bacteria but not in Gram-positive bacteria. Recently, the genome sequences of three strains of Clostridium perfringens have been completed and we identified gene products involved in producing TFP in each strain. Here we show that C. perfringens produces TFP and moves with an unusual form of gliding motility involving groups of densely packed cells moving away from the edge of a colony in curvilinear flares. Mutations introduced into the pilT and pilC genes of C. perfringens abolished motility and surface localization of TFP. Genes encoding TFP are also found in the genomes of all nine Clostridium species sequenced thus far and we demonstrated that Clostridium beijerinckii can move via gliding motility. It has recently been proposed that the Clostridia are the oldest Eubacterial class and the ubiquity of TFP in this class suggests that a Clostridia-like ancestor possessed TFP, which evolved into the forms seen in many Gram-negative species. PMID:16999833

Varga, John J; Nguyen, Van; O'Brien, David K; Rodgers, Katherine; Walker, Richard A; Melville, Stephen B

2006-09-25

350

Microbacterium oleivorans sp. nov. and Microbacterium hydrocarbonoxydans sp. nov., novel crude-oil-degrading Gram-positive bacteria.  

PubMed

A taxonomic study of two crude-oil-degrading, Gram-positive bacterial strains, designated BAS69(T) and BNP48(T), revealed that they represent two novel Microbacterium species. 16S rRNA gene sequence similarity to their closest phylogenetic neighbours was 98.5 % for BAS69(T) (Microbacterium paraoxydans DSM 15019(T) and Microbacterium saperdae DSM 20169(T)) and 99 % for BNP48(T) (Microbacterium luteolum DSM 20143(T)). Levels of DNA-DNA relatedness to the closest phylogenetic neighbours of both strains were between 11 and 38 %. According to phylogenetic analysis, the two strains are distinguishable from all recognized species of Microbacterium. Morphological and physiological characteristics of strains BAS69(T) and BNP48(T) were different from those of phylogenetically closely related Microbacterium species. The diamino acid in the cell-wall peptidoglycan of BAS69(T) is lysine and of BNP48(T) is ornithine. The major menaquinones are MK-11 and MK-12 for both strains. Based on their ability to degrade crude oil, the name Microbacterium oleivorans sp. nov. is proposed for strain BAS69(T) (=DSM 16091(T)=NCIMB 14003(T)) and Microbacterium hydrocarbonoxydans is proposed for strain BNP48(T) (=DSM 16089(T)=NCIMB 14002(T)). PMID:15774639

Schippers, Axel; Bosecker, Klaus; Spröer, Cathrin; Schumann, Peter

2005-03-01

351

Differential targeting of the E-Cadherin/?-Catenin complex by gram-positive probiotic lactobacilli improves epithelial barrier function.  

PubMed

The intestinal ecosystem is balanced by dynamic interactions between resident and incoming microbes, the gastrointestinal barrier, and the mucosal immune system. However, in the context of inflammatory bowel diseases (IBD), where the integrity of the gastrointestinal barrier is compromised, resident microbes contribute to the development and perpetuation of inflammation and disease. Probiotic bacteria have been shown to exert beneficial effects, e.g., enhancing epithelial barrier integrity. However, the mechanisms underlying these beneficial effects are only poorly understood. Here, we comparatively investigated the effects of four probiotic lactobacilli, namely, Lactobacillus acidophilus, L. fermentum, L. gasseri, and L. rhamnosus, in a T84 cell epithelial barrier model. Results of DNA microarray experiments indicating that lactobacilli modulate the regulation of genes encoding in particular adherence junction proteins such as E-cadherin and ?-catenin were confirmed by quantitative reverse transcription-PCR (qRT-PCR). Furthermore, we show that epithelial barrier function is modulated by Gram-positive probiotic lactobacilli via their effect on adherence junction protein expression and complex formation. In addition, incubation with lactobacilli differentially influences the phosphorylation of adherence junction proteins and the abundance of protein kinase C (PKC) isoforms such as PKC? that thereby positively modulates epithelial barrier function. Further insight into the underlying molecular mechanisms triggered by these probiotics might also foster the development of novel strategies for the treatment of gastrointestinal diseases (e.g., IBD). PMID:22179242

Hummel, Stephanie; Veltman, Katharina; Cichon, Christoph; Sonnenborn, Ulrich; Schmidt, M Alexander

2011-12-16

352

Design, synthesis, and characterization of novel tetrahydropyran-based bacterial topoisomerase inhibitors with potent anti-gram-positive activity.  

PubMed

There is an urgent need for new antibacterial drugs that are effective against infections caused by multidrug-resistant pathogens. Novel nonfluoroquinolone inhibitors of bacterial type II topoisomerases (DNA gyrase and topoisomerase IV) have the potential to become such drugs because they display potent antibacterial activity and exhibit no target-mediated cross-resistance with fluoroquinolones. Bacterial topoisomerase inhibitors that are built on a tetrahydropyran ring linked to a bicyclic aromatic moiety through a syn-diol linker show potent anti-Gram-positive activity, covering isolates with clinically relevant resistance phenotypes. For instance, analog 49c was found to be a dual DNA gyrase-topoisomerase IV inhibitor, with broad antibacterial activity and low propensity for spontaneous resistance development, but suffered from high hERG K(+) channel block. On the other hand, analog 49e displayed lower hERG K(+) channel block while retaining potent in vitro antibacterial activity and acceptable frequency for resistance development. Furthermore, analog 49e showed moderate clearance in rat and promising in vivo efficacy against Staphylococcus aureus in a murine infection model. PMID:23968485

Surivet, Jean-Philippe; Zumbrunn, Cornelia; Rueedi, Georg; Hubschwerlen, Christian; Bur, Daniel; Bruyère, Thierry; Locher, Hans; Ritz, Daniel; Keck, Wolfgang; Seiler, Peter; Kohl, Christopher; Gauvin, Jean-Christophe; Mirre, Azely; Kaegi, Verena; Dos Santos, Marina; Gaertner, Mika; Delers, Jonathan; Enderlin-Paput, Michel; Boehme, Maria

2013-09-11

353

Significantly higher procalcitonin levels could differentiate Gram-negative sepsis from Gram-positive and fungal sepsis.  

PubMed

Procalcitonin (PCT) levels can distinguish between infectious and non-infectious systemic inflammatory response. However, there are some differences between Gram-negative (G-), Gram-positive (G+), and fungal bloodstream infections, particularly in different cytokine profiles, severity and mortality. The aim of current study was to examine whether PCT levels can serve as a distinguishing mark between G+, G-, and fungal sepsis as well. One hundred and sixty-six septic patients with positive blood cultures were examined on C-reactive protein (CRP) and PCT on the same date of blood culture evaluation. The median (interquartile range, IQR) of CRP and PCT in G+, G-, and fungal cohorts and comparison of measured values between groups were made using the Kruskal-Wallis test with subsequent Bonferroni's corrections, with p < 0.05. In 83/166 (50 %) of blood cultures, G+ microbes, 78/166 (47 %) G- rods, and 5/166 (3 %) fungi were detected. PCT concentrations (ng/ml) were significantly higher in G- compared to other cohorts: 8.90 (1.88; 32.60) in G-, 0.73 (0.22; 3.40) in G+, and 0.58 (0.35; 0.73) in fungi (p < 0.00001). CRP concentrations did not differ significantly in groups. Significantly higher PCT levels could differentiate G- sepsis from G+ and fungemia. In contrast to CRP, PCT is a good discriminative biomarker in different bloodstream infections. PMID:22644264

Brodská, Helena; Malí?ková, Karin; Adámková, Václava; Benáková, Hana; Š?astná, Markéta Marková; Zima, Tomáš

2012-05-27

354

Metabolome analysis of gram-positive bacteria such as Staphylococcus aureus by GC-MS and LC-MS.  

PubMed

The field of metabolomics has become increasingly important in the context of functional genomics. Together with other "omics" data, the investigation of the metabolome is an essential part of systems biology. Beside the analysis of human and animal biofluids, the investigation of the microbial physiology by methods of metabolomics has gained increased attention. For example, the analysis of metabolic processes during growth or virulence factor expression is crucially important to understand pathogenesis of bacteria. Common bioanalytical techniques for metabolome analysis include liquid and gas chromatographic methods coupled to mass spectrometry (LC-MS and GC-MS) and spectroscopic approaches such as NMR. In order to achieve metabolome data representing the physiological status of a microorganism, well-verified protocols for sampling and analysis are necessary. This chapter presents a detailed protocol for metabolome analysis of the Gram-positive bacterium Staphylococcus aureus. A detailed manual for cell sampling and metabolite extraction is given, followed by the description of the analytical procedures GC-MS and LC-MS. The advantages and limitations of each experimental setup are discussed. Here, a guideline specified for S. aureus metabolomics and information for important protocol steps are presented, to avoid common pitfalls in microbial metabolome analysis. PMID:22131006

Liebeke, Manuel; Dörries, Kirsten; Meyer, Hanna; Lalk, Michael

2012-01-01

355

Evaluation of the RapID CB Plus System for Identification of Corynebacterium Species and Other Gram-Positive Rods  

PubMed Central

Due to the difficulty of identifying Corynebacterium spp. with standard methods, we compared them with the RapID CB Plus system (Remel, Lenexa, Kans. [formerly Innovative Diagnostic Systems, Norcross, Ga.]), which consists of 4 carbohydrate and 14 preformed enzyme tests, for the identification of 98 clinical isolates of Corynebacterium sp., other coryneforms, Listeria monocytogenes, and 17 ATCC strains. Forty (95%) of 42 strains of Corynebacterium spp. were accurately identified to the species level by the RapID CB Plus system, and two additional strains of C. striatum were identified with one additional conventional test for lipid requirement. Twenty-seven (75%) of the 36 coryneform strains tested were identified correctly to the species level. However, three of four strains of Brevibacterium sp. and all seven of the L. monocytogenes strains were identified to the genus level only. Actinomyces strains had variable results, and the one strain of Arcanobacterium haemolyticum tested was not identified. Overall, the RapID CB Plus system compared favorably with the conventional methods, was easy to inoculate and interpret, and is promising as a new method for identification of gram-positive bacilli.

Hudspeth, Marie K.; Gerardo, Sharon Hunt; Citron, Diane M.; Goldstein, Ellie J. C.

1998-01-01

356

A broad-host-range mobilizable shuttle vector for the construction of transcriptional fusions to ?-galactosidase in Gram-positive bacteria  

Microsoft Academic Search

A low-copy-number vector designated pTCV-lac has been constructed to provide a convenient system to analyze regulatory elements in Gram-positive bacteria. The main components of this vector are: (i) the origins of replication of pACYC184 and of the broad-host-range enterococcal plasmid pAM?1, (ii) erythromycin- and kanamycin-resistance-encoding genes for selection in Gram-negative and Gram-positive bacteria, (iii) the transfer origin of the IncP

Claire Poyart; Patrick Trieu-Cuot

1997-01-01

357

Production and immobilization of alkaline protease by Bacillus polymyxa which degrades various proteins  

Microsoft Academic Search

An aerobic gram positive spore forming bacterium, identified as Bacillus polymyxa was isolated from an alkaline soil. This isolated Bacillus produced maximum protease in milk at pH 7. The protease activity against casein was 580 Uml in milk, as the only source of carbon and energy. However, the maximum activity of protease on sorghums extracts, as the only carbon source was

G. EMTIAZI; I. NAHVI; K. BEHESHTI MAAL

2005-01-01

358

Production of a potentially novel anti-microbial substance by Bacillus polymyxa  

Microsoft Academic Search

A bacterial strain, SCE2, identified as Bacillus polymyxa, produced an anti-microbial substance active against yeasts, fungi and different genera of Gram-positive and-negative bacteria, in liquid medium and in plate assays. This substance appeared to be an antibiotic different from the polymyxin group, mainly because of its action against the majority of Gram-positive bacteria tested and its lack of activity against

A. S. Rosado; L. Seldin

1993-01-01

359

Antibacterial activity of cyclodextrins against Bacillus strains.  

PubMed

Growth of alkaliphilic Bacillus halodurans C-125 both on agar plates and in liquid culture was inhibited by methyl-beta-cyclodextrin (CD). Furthermore, resting cells of the strain were lysed by contact with methyl-beta-CD higher than 10 mM. alpha-CD also showed lysis activity against Bacillus and related strains. The activity was not observed with Gram-negative and Gram-positive bacteria except for Bacillus strains. Fluorescence staining and scanning electron microscopy of cells revealed that methyl-beta-CD disrupted cell membranes, and consequently, the cells were lysed. This is a novel physiological property of CDs. PMID:18665349

Zhang, Hui-Min; Li, Zhijun; Uematsu, Katsuyuki; Kobayashi, Tohru; Horikoshi, Koki

2008-07-30

360

Alginase enzyme production by Bacillus circulans.  

PubMed Central

Stream and soil samples were screened for microorganisms that would use alginate from mucoid Pseudomonas aeruginosa as the sole carbon and energy source. A pure culture containing large aerobic rods was isolated. The cells were about 0.8 by 2.5 microns in size, had lateral or peritrichous flagella, had a negative Gram stain reaction, and produced spores on sporulation medium. Purified DNA was approximately 46 mol% G+C as measured by thermal denaturation. From these and other biochemical tests, the organism was identified as Bacillus circulans. The enzyme activity that degraded alginate appeared in the culture medium. Upon gel filtration, alginase activity eluted as a single peak at a position corresponding to a protein of 40,000 daltons. Activity recovered from this one-step, partial purification showed apparent endomannuronidase specificity. Like other alginases previously reported, the enzyme appeared likely to be a lyase (or eliminase). However, no Bacillus species or other gram-positive bacteria have heretofore been reported to produce extracellular enzymes with alginase activity. Several other B. circulans strains from the American Type Culture Collection also appeared to have inducible extracellular alginase activity. Images

Hansen, J B; Doubet, R S; Ram, J

1984-01-01

361

The ESAT-6 gene cluster of Mycobacterium tuberculosis and other high G+C Gram-positive bacteria  

PubMed Central

Background The genome of Mycobacterium tuberculosis H37Rv has five copies of a cluster of genes known as the ESAT-6 loci. These clusters contain members of the CFP-10 (lhp) and ESAT-6 (esat-6) gene families (encoding secreted T-cell antigens that lack detectable secretion signals) as well as genes encoding secreted, cell-wall-associated subtilisin-like serine proteases, putative ABC transporters, ATP-binding proteins and other membrane-associated proteins. These membrane-associated and energy-providing proteins may function to secrete members of the ESAT-6 and CFP-10 protein families, and the proteases may be involved in processing the secreted peptide. Results Finished and unfinished genome sequencing data of 98 publicly available microbial genomes has been analyzed for the presence of orthologs of the ESAT-6 loci. The multiple duplicates of the ESAT-6 gene cluster found in the genome of M. tuberculosis H37Rv are also conserved in the genomes of other mycobacteria, for example M. tuberculosis CDC1551, M. tuberculosis 210, M. bovis, M. leprae, M. avium, and the avirulent strain M. smegmatis. Phylogenetic analyses of the resulting sequences have established the duplication order of the gene clusters and demonstrated that the gene cluster known as region 4 (Rv3444c-3450c) is ancestral. Region 4 is also the only region for which an ortholog could be found in the genomes of Corynebacterium diphtheriae and Streptomyces coelicolor. Conclusions Comparative genomic analysis revealed that the presence of the ESAT-6 gene cluster is a feature of some high-G+C Gram-positive bacteria. Multiple duplications of this cluster have occurred and are maintained only within the genomes of members of the genus Mycobacterium.

Gey van Pittius, Nico C; Gamieldien, Junaid; Hide, Winston; Brown, Gordon D; Siezen, Roland J; Beyers, Albert D

2001-01-01

362

A Novel p-Nitrophenol Degradation Gene Cluster from a Gram-Positive Bacterium, Rhodococcus opacus SAO101  

PubMed Central

p-Nitrophenol (4-NP) is recognized as an environmental contaminant; it is used primarily for manufacturing medicines and pesticides. To date, several 4-NP-degrading bacteria have been isolated; however, the genetic information remains very limited. In this study, a novel 4-NP degradation gene cluster from a gram-positive bacterium, Rhodococcus opacus SAO101, was identified and characterized. The deduced amino acid sequences of npcB, npcA, and npcC showed identity with phenol 2-hydroxylase component B (reductase, PheA2) of Geobacillus thermoglucosidasius A7 (32%), with 2,4,6-trichlorophenol monooxygenase (TcpA) of Ralstonia eutropha JMP134 (44%), and with hydroxyquinol 1,2-dioxygenase (ORF2) of Arthrobacter sp. strain BA-5-17 (76%), respectively. The npcB, npcA, and npcC genes were cloned into pET-17b to construct the respective expression vectors pETnpcB, pETnpcA, and pETnpcC. Conversion of 4-NP was observed when a mixture of crude cell extracts of Escherichia coli containing pETnpcB and pETnpcA was used in the experiment. The mixture converted 4-NP to hydroxyquinol and also converted 4-nitrocatechol (4-NCA) to hydroxyquinol. Furthermore, the crude cell extract of E. coli containing pETnpcC converted hydroxyquinol to maleylacetate. These results suggested that npcB and npcA encode the two-component 4-NP/4-NCA monooxygenase and that npcC encodes hydroxyquinol 1,2-dioxygenase. The npcA and npcC mutant strains, SDA1 and SDC1, completely lost the ability to grow on 4-NP as the sole carbon source. These results clearly indicated that the cloned npc genes play an essential role in 4-NP mineralization in R. opacus SAO101.

Kitagawa, Wataru; Kimura, Nobutada; Kamagata, Yoichi

2004-01-01

363

Relative Roles of the Cellular and Humoral Responses in the Drosophila Host Defense against Three Gram-Positive Bacterial Infections  

PubMed Central

Background Two NF-kappaB signaling pathways, Toll and immune deficiency (imd), are required for survival to bacterial infections in Drosophila. In response to septic injury, these pathways mediate rapid transcriptional activation of distinct sets of effector molecules, including antimicrobial peptides, which are important components of a humoral defense response. However, it is less clear to what extent macrophage-like hemocytes contribute to host defense. Methodology/Principal Findings In order to dissect the relative importance of humoral and cellular defenses after septic injury with three different Gram-positive bacteria (Micrococcus luteus, Enterococcus faecalis, Staphylococcus aureus), we used latex bead pre-injection to ablate macrophage function in flies wildtype or mutant for various Toll and imd pathway components. We found that in all three infection models a compromised phagocytic system impaired fly survival – independently of concomitant Toll or imd pathway activation. Our data failed to confirm a role of the PGRP-SA and GNBP1 Pattern Recognition Receptors for phagocytosis of S. aureus. The Drosophila scavenger receptor Eater mediates the phagocytosis by hemocytes or S2 cells of E. faecalis and S. aureus, but not of M. luteus. In the case of M. luteus and E. faecalis, but not S. aureus, decreased survival due to defective phagocytosis could be compensated for by genetically enhancing the humoral immune response. Conclusions/Significance Our results underscore the fundamental importance of both cellular and humoral mechanisms in Drosophila immunity and shed light on the balance between these two arms of host defense depending on the invading pathogen.

Cho, Ju Hyun; Lee, Janice; Lafarge, Marie-Celine; Kocks, Christine; Ferrandon, Dominique

2011-01-01

364

Structure-function relationships of the non-lanthionine-containing peptide (class II) bacteriocins produced by gram-positive bacteria.  

PubMed

This review focuses on the structure and mode-of-action of non-lanthionine-containing peptide bacteriocins produced by Gram-positive bacteria. These bacteriocins may be divided into four groups: (i) the anti-listerial one-peptide pediocin-like bacteriocins that have very similar amino acid sequences, (ii) the two-peptide bacteriocins that consist of two different peptides, (iii) the cyclic bacteriocins, and (iv) the linear non-pediocin-like one-peptide bacteriocins. These bacteriocins are largely cationic, contain 20 to 70 residues, and kill cells through membrane-permeabilization. The pediocin-like bacteriocins are the ones that are best characterized. Upon contact with target membranes, their cationic N-terminal half forms a beta-sheet-like structure that binds to the target cell surface, while their more hydrophobic helical-containing C-terminal half penetrates into the hydrophobic core of target-cell membranes and apparently binds to the mannose phosphotransferase permease in a manner that results in membrane leakage. Immunity proteins that protect cells from being killed by pediocin-like bacteriocins bind to the bacteriocin-permease complex and prevent bacteriocin-induced membrane-leakage. Recent structural analyses of two-peptide bacteriocins indicate that they form a helix-helix structure that penetrates into cell membranes. Also these bacteriocins may act by binding to integrated membrane proteins. It is proposed that many membrane-active peptide bacteriocins kill target-cells through basically the same mechanism; the common theme being that a membrane-penetrating part of bacteriocins bind to a membrane embedded region of an integrated membrane protein, thereby causing conformational alterations in the protein that in turn lead to membrane-leakage and cell death. PMID:19149588

Nissen-Meyer, J; Rogne, P; Oppegård, C; Haugen, H S; Kristiansen, P E

2009-01-01

365

New polyenic antibiotics active against gram-positive and -negative bacteria. I. Isolation and purification of antibiotics produced by Gluconobacter sp. W-315.  

PubMed

A new antibiotic, tentatively named as AB-315, was isolated from the fermentation broth of Gluconobacter sp. W-315. The antibiotic consists of a mixture of chemically related compounds. These compounds showed similar profiles in UV absorbancy. The antibiotics were active against Gram-positive and -negative bacteria, slightly active against fungi but not against yeasts. PMID:6216233

Watanabe, T; Izaki, K; Takahashi, H

1982-09-01

366

The Mechanism of Action of the Extracellular Bacteriolytic Enzymes of Lysobacter sp. on Gram-Positive Bacteria: The Role of the Cell Wall Anionic Polymers of Target Bacteria  

Microsoft Academic Search

The study of the extracellular bacteriolytic enzymes of Lysobacter sp. showed that they can efficiently hydrolyze the peptidoglycan of gram-positive bacteria provided that there is an electrostatic interaction of these enzymes with the cell wall anionic polymers, teichoic and teichuronic acids in particular. The hydrolytic action of bacteriolytic enzymes on the cell wall largely depends on the negative charge of

O. A. Stepnaya; E. A. Begunova; I. M. Tsfasman; E. M. Tul'skaya; G. M. Streshinskaya; I. B. Naumova; I. S. Kulaev

2004-01-01

367

From the Cover: The molecular switch that activates the cell wall anchoring step of pilus assembly in gram-positive bacteria  

Microsoft Academic Search

Cell surface pili in Gram-positive bacteria orchestrate the colonization of host tissues, evasion of immunity, and the development of biofilms. Recent work revealed that pilus assembly is a biphasic process wherein pilus polymerization is catalyzed by a pilus-specific sortase followed by cell wall anchoring of the pilus that is promoted by the housekeeping sortase. Here, we present molecular genetic and

Anjali Mandlik; Asis Das; Hung Ton-That

2008-01-01

368

Specific Inhibitors of Bacterial Adhesion: Observations From the Study of Gram-Positive Bacteria that Initiate Biofilm Formation on the Tooth Surface  

Microsoft Academic Search

Oral surfaces are bathed in secretory antibodies and other salivary macromolecules that are potential inhibitors of specific microbial adhesion. Indigenous Gram-positive bacteria that colonize teeth, including viridans streptococci and actinomyces, may avoid inhibition of adhesion by host secretory molecules through various strategies that involve the structural design and binding properties of bacterial adhesins and receptors. Further studies to define the

J. O. Cisar; Y. Takahashi; S. Ruhl; J. A. Donkersloot; A. L. Sandberg

1997-01-01

369

Type IV Pili and the CcpA Protein Are Needed for Maximal Biofilm Formation by the Gram-Positive Anaerobic Pathogen Clostridium perfringens  

Microsoft Academic Search

The predominant organizational state of bacteria in nature is biofilms. Biofilms have been shown to increase bacterial resistance to a variety of stresses. We demonstrate for the first time that the anaerobic gram-positive pathogen Clostridium perfringens forms biofilms. At the same concentration of glucose in the medium, optimal biofilm formation depended on a functional CcpA protein. While the ratio of

John J. Varga; Blair Therit; Stephen B. Melville

2008-01-01

370

Purification and Characterization of Organic Solvent and Detergent Tolerant Lipase from Thermotolerant Bacillus sp. RN2  

PubMed Central

The aim of this study was to characterize the organic solvent and detergent tolerant properties of recombinant lipase isolated from thermotolerant Bacillus sp. RN2 (Lip-SBRN2). The isolation of the lipase-coding gene was achieved by the use of inverse and direct PCR. The complete DNA sequencing of the gene revealed that the lip-SBRN2 gene contains 576 nucleotides which corresponded to 192 deduced amino acids. The purified enzyme was homogeneous with the estimated molecular mass of 19 kDa as determined by SDS-PAGE and gel filtration. The Lip-SBRN2 was stable in a pH range of 9–11 and temperature range of 45–60 °C. The enzyme was a non metallo-monomeric protein and was active against pNP-caprylate (C8) and pNP-laurate (C12) and coconut oil. The Lip-SBRN2 exhibited a high level of activity in the presence of 108% benzene, 102.4% diethylether and 112% SDS. It is anticipated that the organic solvent and detergent tolerant enzyme secreted by Bacillus sp. RN2 will be applicable as catalysts for reaction in the presence of organic solvents and detergents.

Kanjanavas, Pornpimon; Khuchareontaworn, Sintawee; Khawsak, Paisarn; Pakpitcharoen, Arda; Pothivejkul, Khajeenart; Santiwatanakul, Somchai; Matsui, Kenji; Kajiwara, Tadahiko; Chansiri, Kosum

2010-01-01

371

Purification and Characterization of Organic Solvent and Detergent Tolerant Lipase from Thermotolerant Bacillus sp. RN2.  

PubMed

The aim of this study was to characterize the organic solvent and detergent tolerant properties of recombinant lipase isolated from thermotolerant Bacillus sp. RN2 (Lip-SBRN2). The isolation of the lipase-coding gene was achieved by the use of inverse and direct PCR. The complete DNA sequencing of the gene revealed that the lip-SBRN2 gene contains 576 nucleotides which corresponded to 192 deduced amino acids. The purified enzyme was homogeneous with the estimated molecular mass of 19 kDa as determined by SDS-PAGE and gel filtration. The Lip-SBRN2 was stable in a pH range of 9-11 and temperature range of 45-60 °C. The enzyme was a non metallo-monomeric protein and was active against pNP-caprylate (C8) and pNP-laurate (C12) and coconut oil. The Lip-SBRN2 exhibited a high level of activity in the presence of 108% benzene, 102.4% diethylether and 112% SDS. It is anticipated that the organic solvent and detergent tolerant enzyme secreted by Bacillus sp. RN2 will be applicable as catalysts for reaction in the presence of organic solvents and detergents. PMID:21152301

Kanjanavas, Pornpimon; Khuchareontaworn, Sintawee; Khawsak, Paisarn; Pakpitcharoen, Arda; Pothivejkul, Khajeenart; Santiwatanakul, Somchai; Matsui, Kenji; Kajiwara, Tadahiko; Chansiri, Kosum

2010-09-29

372

Randomized trial of the addition of gram-positive prophylaxis to standard antimicrobial prophylaxis for patients undergoing autologous bone marrow transplantation.  

PubMed

The purpose of the study reported here was to investigate the impact of prophylaxis against gram-positive infections in patients undergoing high-dose chemotherapy and autologous bone marrow transplantation in a randomized trial. Forty-three patients undergoing high-dose chemotherapy with autologous bone marrow transplant were enrolled in a nonblinded randomized trial to receive or not to receive prophylaxis for gram-positive infections with 10(6) U of penicillin intravenously (i.v.) every 6 h (q6h) (if penicillin allergic, 750 mg of vancomycin i.v. q12h) in addition to standard antimicrobial prophylaxis with 400 mg of norfloxacin orally three times a day, 200 mg of fluconazole orally once a day, and 5 mg of acyclovir per kg of body weight i.v. q12h. The patients were being treated for germ cell cancer (n = 15), breast cancer (n = 16), Hodgkin's disease (n = 3), non-Hodgkin's lymphoma (n = 4), acute myeloid leukemia (n = 1), acute lymphoblastic leukemia (n = 1), and ovarian cancer (n = 3). The trial was stopped because of excess morbidity in the form of streptococcal septic shock in the group not receiving gram-positive prophylaxis. There were significantly fewer overall infections (10 versus 3; P = 0.016) and streptococcal infections (9 versus 1; P = 0.0078) in the group receiving gram-positive prophylaxis. There were no significant differences in the numbers of deaths, duration of broad-spectrum antibiotics, or incidence of neutropenic fever between the two groups. Prophylaxis for gram-positive infections with penicillin or vancomycin is effective in reducing the incidence of streptococcal infections in patients undergoing high-dose chemotherapy and autologous bone marrow transplant. However, this approach may carry a risk of fostering resistance among streptococci to penicillin or vancomycin. PMID:8203857

Broun, E R; Wheat, J L; Kneebone, P H; Sundblad, K; Hromas, R A; Tricot, G

1994-03-01

373

Saponin promotes rapid identification and antimicrobial susceptibility profiling of Gram-positive and Gram-negative bacteria in blood cultures with the Vitek 2 system.  

PubMed

The rapid identification and antimicrobial susceptibility testing (AST) of bacteria in clinical blood cultures is crucial to optimise antimicrobial therapy. A previous study involving small sample numbers revealed that the addition of saponin to blood cultures, further referred to as the new method, shortened considerably the turn-around time for the identification and AST of Gram-positive cocci as compared to the current method involving an overnight subculture. Here, we extend previous results and compare the identification and AST of blood cultures containing Gram-negative bacilli by the new and current methods. The identification and AST of 121 Gram-positive and 109 Gram-negative bacteria in clinical monomicrobial blood cultures by the new and current methods and, in the case of Gram-negative bacilli, by direct (no additions) inoculation into an automated system (rapid method) was assessed using the Vitek 2 system. Discrepancies between the results obtained with the different methods were solved by manual methods. The new method correctly identified 88 % of Gram-positive and 98 % of Gram-negative bacteria, and the rapid method correctly identified 94 % of Gram-negative bacteria. The AST for all antimicrobials by the new method were concordant with the current method for 55 % and correct for an additional 9 % of Gram-positive bacteria, and concordant with the current method for 62 % and correct for an additional 21 % of Gram-negative bacilli. The AST by the rapid method was concordant with the current method for 62 % and correct for an additional 12 % of Gram-negative bacilli. Together, saponin-treated monomicrobial blood cultures allow rapid and reliable identification and AST of Gram-positive and Gram-negative bacteria. PMID:23114724

Lupetti, A; Barnini, S; Morici, P; Ghelardi, E; Nibbering, P H; Campa, M

2012-11-02

374

Conjugative plasmid pAW63 brings new insights into the genesis of the Bacillus anthracis virulence plasmid pXO2 and of the Bacillus thuringiensis plasmid pBT9727  

Microsoft Academic Search

BACKGROUND: Bacillus cereus, Bacillus anthracis and Bacillus thuringiensis belong to the genetically close-knit Bacillus cereus sensu lato group, a family of rod-shaped Gram-positive bacteria. pAW63 is the first conjugative plasmid from the B. cereus group to be completely sequenced. RESULTS: The 71,777 bp nucleotide sequence of pAW63 reveals a modular structure, including a 42 kb tra region encoding homologs of

Géraldine A Van der Auwera; Lars Andrup; Jacques Mahillon

2005-01-01

375

Identification, Evolution, and Essentiality of the Mevalonate Pathway for Isopentenyl Diphosphate Biosynthesis in Gram-Positive Cocci  

Microsoft Academic Search

The mevalonate pathway and the glyceraldehyde 3-phosphate (GAP)-pyruvate pathway are alternative routes for the biosynthesis of the central isoprenoid precursor, isopentenyl diphosphate. Genomic analysis revealed that the staphylococci, streptococci, and enterococci possess genes predicted to encode all of the enzymes of the mevalonate pathway and not the GAP-pyruvate pathway, unlike Bacillus subtilis and most gram-negative bacteria studied, which possess only

E. IMOGEN WILDING; JAMES R. BROWN; ALEXANDER P. BRYANT; ALISON F. CHALKER; DAVID J. HOLMES; KAREN A. INGRAHAM; SERBAN IORDANESCU; CHI Y. SO; MARTIN ROSENBERG; MICHAEL N. GWYNN

2000-01-01

376

Homolactic fermentation from glucose and cellobiose using Bacillus subtilis  

Microsoft Academic Search

BACKGROUNG: Biodegradable plastics can be made from polylactate, which is a polymer made from lactic acid. This compound can be produced from renewable resources as substrates using microorganisms. Bacillus subtilis is a Gram-positive bacterium recognized as a GRAS microorganism (generally regarded as safe) by the FDA. B. subtilis produces and secretes different kind of enzymes, such as proteases, cellulases, xylanases

Susana Romero-Garcia; Claudia Hernández-Bustos; Enrique Merino; Guillermo Gosset; Alfredo Martinez

2009-01-01

377

The DNA secondary structure of the Bacillus subtilis genome  

Microsoft Academic Search

The entire genomic DNA sequence of the Gram-positive bacterium Bacillus subtilis reported in the SubtiList database has been subjected in this work to a complete bioinformatic analysis of the potential formation of secondary DNA structures such as hairpins and bending. The most significant of these structures have been mapped with respect to their genomic location and compared to those structures

Valentina Tosato; Kresimir Gjuracic; Kristian Vlahovicek; Sandor Pongor; Antoine Danchin; Carlo V. Bruschi

2003-01-01

378

The extracellular proteome of Bacillus subtilis under secretion stress conditions  

Microsoft Academic Search

The accumulation of malfolded proteins in the cell envelope of the Gram-positive eubacterium Bacillus subtilis was previously shown to provoke a so-called secretion stress response. In the present studies, proteomic approaches were employed to identify changes in the extracellular proteome of B. subtilis in response to secretion stress. The data shows that, irrespective of the way in which secretion stress

Haike Antelmann; Elise Darmon; David Noone; Jan-Willem Veening; Helga Westers; Sierd Bron; Oscar P. Kuipers; Kevin M. Devine; Michael Hecker; Jan Maarten van Dijl

2003-01-01

379

Role of superoxide in the germination of Bacillus anthracis endospores  

Microsoft Academic Search

The spore forming Gram-positive bacterium Bacillus anthracis, the causative agent of anthrax, has achieved notoriety due to its use as a bioterror agent. In the environment, B. anthracis exists as a dormant endospore. Germination of endospores during their internalization within the myeloid phagocyte, and the ability of those endospores to survive exposure to antibacterial killing mechanisms such as superoxide (O2-),

Les Baillie; Stephen Hibbs; Pei Tsai; Guan-Liang Cao; Gerald M. Rosen

2005-01-01

380

Electrotransformation of Bacillus mojavensis with fluorescent protein markers  

Technology Transfer Automated Retrieval System (TEKTRAN)

Gram-positive endophytic bacteria are difficult to transform. To study endophytic interactions between Bacillus mojavensis and maize, a method was developed to transform this species by electroporation with three fluorescent protein expressing integrative plasmids: pSG1154, pSG1192, and pSG1193. The...

381

Overcoming function annotation errors in the Gram-positive pathogen Streptococcus suis by a proteomics-driven approach  

PubMed Central

Background Annotation of protein-coding genes is a key step in sequencing projects. Protein functions are mainly assigned on the basis of the amino acid sequence alone by searching of homologous proteins. However, fully automated annotation processes often lead to wrong prediction of protein functions, and therefore time-intensive manual curation is often essential. Here we describe a fast and reliable way to correct function annotation in sequencing projects, focusing on surface proteomes. We use a proteomics approach, previously proven to be very powerful for identifying new vaccine candidates against Gram-positive pathogens. It consists of shaving the surface of intact cells with two proteases, the specific cleavage-site trypsin and the unspecific proteinase K, followed by LC/MS/MS analysis of the resulting peptides. The identified proteins are contrasted by computational analysis and their sequences are inspected to correct possible errors in function prediction. Results When applied to the zoonotic pathogen Streptococcus suis, of which two strains have been recently sequenced and annotated, we identified a set of surface proteins without cytoplasmic contamination: all the proteins identified had exporting or retention signals towards the outside and/or the cell surface, and viability of protease-treated cells was not affected. The combination of both experimental evidences and computational methods allowed us to determine that two of these proteins are putative extracellular new adhesins that had been previously attributed a wrong cytoplasmic function. One of them is a putative component of the pilus of this bacterium. Conclusion We illustrate the complementary nature of laboratory-based and computational methods to examine in concert the localization of a set of proteins in the cell, and demonstrate the utility of this proteomics-based strategy to experimentally correct function annotation errors in sequencing projects. This approach also contributes to provide strong experimental evidences that can be used to annotate those proteins for which a Gene Ontology (GO) term has not been assigned so far. Function annotation correction would then improve the identification of surface-associated proteins in bacterial pathogens, thus accelerating the discovery of new vaccines in infectious disease research.

Rodriguez-Ortega, Manuel J; Luque, Inmaculada; Tarradas, Carmen; Barcena, Jose A

2008-01-01

382

Bacillus and Paenibacillus spp.: Potential PGPR for Sustainable Agriculture  

Microsoft Academic Search

\\u000a The Gram-positive aerobic endospore-forming bacteria (AEFB) belonging to the genus Bacillus and Paenibacillus are essentially ubiquitous and occur abundantly in most rhizospheric soils. In the rhizosphere, species of these two genera\\u000a are involved in atmospheric nitrogen fixation, solubilization of soil phosphorus and uptake of micronutrients, and production\\u000a of phytohormones and antimicrobial metabolites. Multiple species of Bacillus and Paenibacillus affect the

Venkadasamy Govindasamy; Murugesan Senthilkumar; Vellaichamy Magheshwaran; Upendra Kumar; Pranita Bose; Vikas Sharma; Kannepalli Annapurna

383

Type I and Type II mechanisms of antimicrobial photodynamic therapy: An in vitro study on Gram-negative and Gram-positive bacteria  

PubMed Central

Background and Objectives Antimicrobial photodynamic therapy (APDT) employs a nontoxic photosensitizer (PS) and visible light, which in the presence of oxygen produce reactive oxygen species (ROS), such as singlet oxygen (1O2, produced via Type II mechanism) and hydroxyl radical (HO•, produced via Type I mechanism). This study examined the relative contributions of 1O2 and HO• to APDT killing of Gram-positive and Gram-negative bacteria. Study Design/Materials and Methods Fluorescence probes, 3'-(p-hydroxyphenyl)-fluorescein (HPF) and singlet oxygen sensor green reagent (SOSG) were used to determine HO• and 1O2 produced by illumination of two PS: tris-cationic-buckminsterfullerene (BB6) and a conjugate between polyethylenimine and chlorin(e6) (PEI–ce6). Dimethylthiourea is a HO• scavenger, while sodium azide (NaN3) is a quencher of 1O2. Both APDT and killing by Fenton reaction (chemical generation of HO•) were carried out on Gram-positive bacteria (Staphylococcus aureus and Enteroccoccus fecalis) and Gram-negative bacteria (Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa. Results Conjugate PEI-ce6 mainly produced 1O2 (quenched by NaN3), while BB6 produced HO• in addition to 1O2 when NaN3 potentiated probe activation. NaN3 also potentiated HPF activation by Fenton reagent. All bacteria were killed by Fenton reagent but Gram-positive bacteria needed a higher concentration than Gram-negatives. NaN3 potentiated Fenton-mediated killing of all bacteria. The ratio of APDT killing between Gram-positive and Gram-negative bacteria was 2 or 4:1 for BB6 and 25:1 for conjugate PEI-ce6. There was a NaN3 dose dependent inhibition of APDT killing using both PEI-ce6 and BB6 against Gram-negative bacteria while NaN3 almost failed to inhibit killing of Gram-positive bacteria. Conclusion Azidyl radicals may be formed from NaN3 and HO•. It may be that Gram-negative bacteria are more susceptible to HO• while Gram-positive bacteria are more susceptible to 1O2. The differences in NaN3 inhibition may reflect differences in the extent of PS binding to bacteria (microenvironment) or differences in penetration of NaN3 into cell walls of bacteria.

Huang, Liyi; Xuan, Yi; Koide, Yuichiro; Zhiyentayev, Timur; Tanaka, Masamitsu; Hamblin, Michael R.

2012-01-01

384

Potentiation of antibiotic activity by EDTA-tromethamine against three clinically isolated Gram-positive resistant bacteria. An in vitro investigation  

Microsoft Academic Search

Thein vitro synergistic effects of combinations of EDTA-tromethamine and five antimicrobial agents (ampicillin, cephalexin, oxytetracycline, streptomycin and sulphadimethoxine) on three clinically isolated Gram-positive bacteria (Staphylococcus aureus, Staphylococcus hominis andStreptococcus faecium) were investigated. The bacteria had been isolated from three cases of canine otitis resistant to ß-lactam antibiotic therapy. The antimicrobial activity was evaluated by measuring the minimal inhibitory concentration for

A. M. Farca; P. Nebbia; G. Re

1994-01-01

385

Lactobacillus plantarum gene clusters encoding putative cell-surface protein complexes for carbohydrate utilization are conserved in specific gram-positive bacteria  

Microsoft Academic Search

BACKGROUND: Genomes of gram-positive bacteria encode many putative cell-surface proteins, of which the majority has no known function. From the rapidly increasing number of available genome sequences it has become apparent that many cell-surface proteins are conserved, and frequently encoded in gene clusters or operons, suggesting common functions, and interactions of multiple components. RESULTS: A novel gene cluster encoding exclusively

Roland Siezen; Jos Boekhorst; Lidia Muscariello; Douwe Molenaar; Bernadet Renckens; Michiel Kleerebezem

2006-01-01

386

An integron of class 1 is present on the plasmid pCG4 from Gram-positive bacterium Corynebacterium glutamicum  

Microsoft Academic Search

The streptomycin\\/spectinomycin resistance determinant of the 29-kb plasmid pCG4 from Corynebacterium glutamicum was found to be a part of a typical class 1 integron. The sequence analysis revealed that the integron (designated InCg) identified in this Gram-positive bacterium is almost identical to the integron InC present on the plasmid pSA1700 from the Gram-negative bacterium Pseudomonas aeruginosa. Differences in only two

Jan Nešvera; Jitka Hochmannová; Miroslav Pátek

1998-01-01

387

Differential Roles of TLR2 and TLR4 in Recognition of Gram-Negative and Gram-Positive Bacterial Cell Wall Components  

Microsoft Academic Search

Toll-like receptor (TLR) 2 and TLR4 are implicated in the recognition of various bacterial cell wall components, such as lipopolysaccharide (LPS). To investigate in vivo roles of TLR2, we generated TLR2-deficient mice. In contrast to LPS unresponsiveness in TLR4-deficient mice, TLR2-deficient mice responded to LPS to the same extent as wild-type mice. TLR2-deficient macrophages were hyporesponsive to several Gram-positive bacterial

Osamu Takeuchi; Katsuaki Hoshino; Taro Kawai; Hideki Sanjo; Haruhiko Takada; Tomohiko Ogawa; Kiyoshi Takeda; Shizuo Akira

1999-01-01

388

Photoinactivation of bacteria. Use of a cationic water-soluble zinc phthalocyanine to photoinactivate both Gram-negative and Gram-positive bacteria  

Microsoft Academic Search

The photosensitization of microorganisms is potentially useful for sterilization and for the treatment of certain bacterial diseases. Unit now, any broad spectrum approach has been inhibited because, although Gram-positive bacteria can be photoinactivated by a range of photosensitizer, Gram-negative bacteria have not usually been susceptible to photosensitized destruction.In the present work, it has been shown that the Gram-negative bacteria Escheria

Andrew Minnock; David I. Vernon; Jack Schofield; John Griffiths; J. Howard Parish; Stanley B. Brown

1996-01-01

389

Epidemiologic trends in nosocomial and community-acquired infections due to antibiotic-resistant gram-positive bacteria: the role of streptogramins and other newer compounds  

Microsoft Academic Search

The Gram-positive cocci have clearly re-emerged as important pathogens world-wide in the past two decades. Staphylococci, including the coagulase-negative staphylococci and Staphylococcus aureus, and the enterococci account for approximately one-third of all blood stream infections and as much as 50% of nosocomial blood stream infections. Although Streptococcus pneumoniae is often considered a community-acquired pathogen, it is also an important cause

RonaldN Jones; DonaldE Low; MichaelA Pfaller

1999-01-01

390

Obtaining and characterization of DNA-containing micromummies of yeasts and gram-positive bacteria with enhanced cell wall permeability: Application in PCR  

Microsoft Academic Search

The procedure of obtaining DNA-containing cell envelopes (“micromummies”) of bacteria, yeasts, and fungi using chaotropic\\u000a salts has been developed previously and the possibility of their direct application in PCR has been demonstrated. The fine\\u000a structure of micromummies has been studied by electron microscopic methods. This work has demonstrated that additional treatment\\u000a of micromummies of yeasts and gram-positive bacteria with proteinase

V. N. Danilevich; V. I. Duda; N. E. Suzina; E. V. Grishin

2007-01-01

391

In vitro Activity of Monoclonal and Recombinant Yeast Killer Toxin-like Antibodies Against Antibiotic-resistant Gram-positive Cocci  

Microsoft Academic Search

Background: Monoclonal (mAbKT) and recom- binant single-chain (scFvKT) anti-idiotypic anti- bodies were produced to represent the internal image of a yeast killer toxin (KT) characterized by a wide spectrum of antimicrobial activity, including Gram-positive cocci. Pathogenic eukaryotic and prokaryotic microorganisms, such as Candida albi- cans, Pneumocystis carinii, and a multidrug-resistant strain of Mycobacterium tuberculosis, presenting spe- cific, although yet undefined,

S. Conti; W. Magliani; S. Arseni; E. Dieci; A. Salati; P. E. Varaldo; L. Polonelli

2000-01-01

392

Isolation and Mode of Action of a Staphylococcin-like Substance Active Against Gram-positive and Gram-negative Bacteria  

Microsoft Academic Search

Screening of non-phage group I1 Staphylococcus aureus strains for antagonistic substances revealed one particular strain, S. aureus D91, to excrete a substance with a wide spectrum of activity; both Gram-positive and Gram-negative bacteria were susceptible. The staphylococ- cin-like substance D91 produced by this strain was partially purified by column chromato- graphy on Sephadex G-50, DEAE-cellulose, Phenyl Sepharose CL-4B and Sephadex

O. A. KADER; H.-G. SAHL; H. BRANDIS

1984-01-01

393

Phagocytic and Tumor Necrosis Factor Alpha Response of Human Mast Cells following Exposure to Gram-Negative and Gram-Positive Bacteria  

Microsoft Academic Search

Recent studies have implicated rodent mast cells in the innate immune response to infectious bacteria. We report that cord blood-derived human mast cells (CBHMC) obtained from culture of cord blood progenitors phagocytozed and killed various gram-negative and gram-positive bacteria and simultaneously released con- siderable amounts of tumor necrosis factor alpha. Overall, the extent of the endocytic and exocytic response of

MICHEL AROCK; ELAINE ROSS; GENEVIEVE AVERLANT; ZHIMIN GAO; SOMAN N. ABRAHAM

1998-01-01

394

Phylogenetic Placement of Dialister pneumosintes (formerly Bacteroides pneumosintes) within the Sporomusa Subbranch of the Clostridium Subphylum of the Gram-Positive Bacteria  

Microsoft Academic Search

The nucleotide sequence of the 16s rRNA gene of the type strain of Dialisfer pneumosinfes was determined. Phylogenetic analysis revealed that this species belongs to the Sporomusa branch of the Clostridum subphylum of the gram-positive bacteria and should therefore be excluded from the family Bacferoidaceae. Within this branch, which encompasses several other gram-negative taxa, such as Acidarninococcus, Pectinatus, Phascolar- cobacferium,

ANNE WILLEMS; MATTHEW D. COLLINS

1995-01-01

395

TetZ, a New Tetracycline Resistance Determinant Discovered in Gram-Positive Bacteria, Shows High Homology to Gram-Negative Regulated Efflux Systems  

Microsoft Academic Search

The complete nucleotide sequence of the tetracycline resistance plasmid pAG1 from the gram-positive soil bacterium Corynebacterium glutamicum 22243 (formerly Corynebacterium melassecola 22243) was determined. The R-plasmid has a size of 19,751 bp and contains at least 18 complete open reading frames. The resistance determinant of pAG1 revealed homology to gram-negative tetracycline efflux and repressor systems of Tet classes A through

Andreas Tauch; Alfred Pühler; Jörn Kalinowski; Georg Thierbach

2000-01-01

396

Kineococcus aurantiacus gen. nov., sp. nov., a New Aerobic, Gram-Positive, Motile Coccus with rneso-Diaminopimelic Acid and Arabinogalactan in the Cell Wall  

Microsoft Academic Search

A new aerobic, gram-positive, motile coccus isolated from soil is described. Strain RA 333= (T = type strain) has the following characteristics: menaquinone MK-9(H2); G+C content of DNA of 73.9 mol%; meso- diaminopimelic acid, glutamic acid, and alanine in a molar ratio of ca. 1:1:2 (type Aly); and arabinose and galactose in the cell wall. The two sugars are contained

AKIRA YOKOTA; TOMOHIKO TAMURA; TADASHI NISHII; TORU HASEGAWA

397

Messenger RNA Turnover Processes in Escherichia coli, Bacillus subtilis, and Emerging Studies in Staphylococcus aureus  

PubMed Central

The regulation of mRNA turnover is a recently appreciated phenomenon by which bacteria modulate gene expression. This review outlines the mechanisms by which three major classes of bacterial trans-acting factors, ribonucleases (RNases), RNA binding proteins, and small noncoding RNAs (sRNA), regulate the transcript stability and protein production of target genes. Because the mechanisms of RNA decay and maturation are best characterized in Escherichia coli, the majority of this review will focus on how these factors modulate mRNA stability in this organism. However, we also address the effects of RNases, RNA binding proteins, sRNAs on mRNA turnover, and gene expression in Bacillus subtilis, which has served as a model for studying RNA processing in gram-positive organisms. We conclude by discussing emerging studies on the role modulating mRNA stability has on gene expression in the important human pathogen Staphylococcus aureus.

Anderson, Kelsi L.; Dunman, Paul M.

2009-01-01

398

Microbe forensics: Oxygen and hydrogen stable isotope ratios in Bacillus subtilis cells and spores  

PubMed Central

Bacillus subtilis, a Gram-positive, endospore-forming soil bacterium, was grown in media made with water of varying oxygen (?18O) and hydrogen (?D) stable isotope ratios. Logarithmically growing cells and spores were each harvested from the cultures and their ?18O and ?D values determined. Oxygen and hydrogen stable isotope ratios of organic matter were linearly related with those of the media water. We used the relationships determined in these experiments to calculate the effective whole-cell fractionation factors between water and organic matter for B. subtilis. We then predicted the ?18O and ?D values of spores produced in nutritionally identical media and local water sources for five different locations around the United States. Each of the measured ?18O and ?D values of the spores matched the predicted values within a 95% confidence interval, indicating that stable isotope ratio analyses may be a powerful tool for tracing the geographic point-of-origin for microbial products.

Kreuzer-Martin, Helen W.; Lott, Michael J.; Dorigan, Janet; Ehleringer, James R.

2003-01-01

399

Molecular study of a squalene cyclase homolog gene in Bacillus subtilis  

NASA Astrophysics Data System (ADS)

Polycyclic triterpenoids such as hopanes and steranes are formed by enzymatic cyclization of linear isoprenoid precursors by squalene cyclases and oxidosqualene cyclases. Due to their amazing preservation potential, polycyclic triterpenoids have been used to indicate the source of organic matter in oils and sediments for decades, although many cannot be attributed to known organisms and genes. To bridge the gap between the genomic database and the geochemical record, we are using molecular tools to study the expression, intracellular localization, and products of a squalene cyclase homolog found in Bacillus subtilis, a Gram-positive soil bacterium. We find that the gene is expressed during sporulation and is localized to the spore coat. Our results may help to understand the source of some previously unassigned natural products, and they may also provide clues to the physiological role of triterpenoids in the Bacillales.

Bosak, T.; Pearson, A.; Losick, R.

2005-12-01

400

Protein secretion in Bacillus species.  

PubMed Central

Bacilli secrete numerous proteins into the environment. Many of the secretory proteins, their export signals, and their processing steps during secretion have been characterized in detail. In contrast, the molecular mechanisms of protein secretion have been relatively poorly characterized. However, several components of the protein secretion machinery have been identified and cloned recently, which is likely to lead to rapid expansion of the knowledge of the protein secretion mechanism in Bacillus species. Comparison of the presently known export components of Bacillus species with those of Escherichia coli suggests that the mechanism of protein translocation across the cytoplasmic membrane is conserved among gram-negative and gram-positive bacteria differences are found in steps preceding and following the translocation process. Many of the secretory proteins of bacilli are produced industrially, but several problems have been encountered in the production of Bacillus heterologous secretory proteins. In the final section we discuss these problems and point out some possibilities to overcome them.

Simonen, M; Palva, I

1993-01-01

401

Ecological significance and some biotechnological application of an organic solvent stable alkaline serine protease from Bacillus subtilis strain DM04  

Microsoft Academic Search

An organic solvent stable, alkaline serine protease (Bsubap-I) with molecular mass of 33.1kDa, purified from Bacillus subtilis DM-04 showed optimum activity at temperature and pH range of 37–45°C and 10.0–10.5, respectively. The enzyme activity of Bsubap-I was significantly enhanced in presence of Fe2+. The thermal resistance and stability and of Bsubap-I in presence of surfactants, detergents, and organic solvents, and

Sudhir K. Rai; Ashis K. Mukherjee

2009-01-01

402

Circulating Inflammatory Mediators during Start of Fever in Differential Diagnosis of Gram-Negative and Gram-Positive Infections in Leukopenic Rats  

PubMed Central

Gram-negative and gram-positive infections have been considered the most important causes of morbidity and mortality in patients with leukopenia following chemotherapy. However, discrimination between bacterial infections and harmless fever episodes is difficult. Because classical inflammatory signs of infection are often absent and fever is frequently the only sign of infection, the aim of this study was to assess the significance of serum interleukin-6 (IL-6), IL-10, macrophage inflammatory protein-2 (MIP-2), procalcitonin (PCT), and C-reactive protein (CRP) patterns in identifying bacterial infections during start of fever in normal and cyclophosphamide-treated (leukopenic) rats following an injection of lipopolysaccharide (LPS) or muramyl dipeptide (MDP) as a model for gram-negative and gram-positive bacterial infections. We found that, compared to normal rats, immunosuppressed animals exhibited significantly higher fevers and lesser production of all mediators, except IL-6, after toxin challenge. Moreover, compared to rats that received MDP, both groups of animals that received an equivalent dose of LPS showed significantly higher fevers and greater increase in serum cytokine levels. Furthermore, in contrast to those in immunocompetent rats, serum levels of IL-6 and MIP-2 were not significantly changed in leukopenic animals after MDP injection. Other serum markers such as PCT and CRP failed to discriminate between bacterial stimuli in both groups of animals. These results suggest that the use of the analyzed serum markers at an early stage of fever could give useful information for the clinician for excluding gram-negative from gram-positive infections.

Tavares, Eva; Maldonado, Rosario; Ojeda, Maria L.; Minano, Francisco J.

2005-01-01

403

Role of protonated and neutral forms of macrolides in binding to ribosomes from gram-positive and gram-negative bacteria.  

PubMed Central

Erythromycin binds to a single site on the bacterial 50S ribosomal subunit and perturbs protein synthesis. However, erythromycin contains desosamine and thus exists in both protonated (greater than 96%) and neutral (less than 4%) forms at physiological pH because of the pKa of the dimethylamino group. We therefore examined the relative roles of both forms in binding to ribosomes isolated from two species each of gram-positive and gram-negative bacteria. We developed a system to directly measure the forward (association) rate constant of formation of the macrolide-ribosome complex, and we have measured both the forward and reverse (dissociation) rate constants as a function of pH. Forward rate constants and binding affinity did not correlate with pH when the interaction of erythromycin with ribosomes from both gram-positive and gram-negative bacteria was examined, demonstrating that the protonated form of this macrolide binds to ribosomes. Conversely, the neutral form of macrolide cannot be the sole binding species and appears to bind with the same kinetics as the protonated form. Forward rate constants were 3- to 4-fold greater at physiological pH, and binding affinity calculated from rate constants was 5- to 10-fold greater than previously estimated. Similar results were obtained with azithromycin, a novel 15-membered macrolide that contains an additional tertiary amine in the macrolide ring. Ribosome- and macrolide-specific kinetic parameters were demonstrated at neutral pH and may be related to the potency of the two macrolides against gram-positive and gram-negative bacteria.

Goldman, R C; Fesik, S W; Doran, C C

1990-01-01

404

Impact of Results of a Rapid Staphylococcus aureus Diagnostic Test on Prescribing of Antibiotics for Patients with Clustered Gram-Positive Cocci in Blood Cultures  

PubMed Central

In tropical northern Australia, approximately 20% of Staphylococcus aureus bacteremia is caused by methicillin-resistant Staphylococcus aureus (MRSA). We prospectively evaluated the impact on clinician antibiotic prescribing of the results obtained from performing the GeneXpert MRSA/SA test on 151 positive blood cultures with clustered Gram-positive cocci. The GeneXpert result led to earlier appropriate prescription of vancomycin for 54% of patients with MRSA; 25% of patients avoided vancomycin, and 16% of patients had all antibiotics ceased.

Davies, Jane; Gordon, Claire L.; Tong, Steven Y. C.; Baird, Robert W.

2012-01-01

405

In Vitro Activities of LY333328 and Comparative Agents against Nosocomial Gram-Positive Pathogens Collected in a 1997 Global Surveillance Study  

PubMed Central

The in vitro activity of LY333328 was evaluated for 1,479 nosocomial gram-positive pathogens isolated in 12 countries during 1997. LY333328 MICs at which 90% of the isolates tested were inhibited for Enterococcus faecalis (n = 351), Enterococcus faecium (n = 100), Staphylococcus aureus (n = 593), coagulase-negative Staphylococcus species (n = 325), and Streptococcus pneumoniae (n = 110) were 1, 1, 2, 2, and 0.015 ?g/ml, respectively. LY333328 demonstrated potent activity against isolates of vancomycin-resistant enterococci, oxacillin-resistant staphylococci, and penicillin-resistant pneumococci.

Zeckel, Michael L.; Preston, David A.; Allen, Bradley S.

2000-01-01

406

Bacillus cereus var. toyoi promotes growth, affects the histological organization and microbiota of the intestinal mucosa in rainbow trout fingerlings.  

PubMed

In this preliminary study, we evaluated the effects of a gram-positive soil bacteria Bacillus cereus var. toyoi on the growth performance, digestive enzyme activities, intestinal morphology, and microbiota in rainbow trout Oncorhynchus mykiss fingerlings. Trout were maintained in a recirculation system and fed 2 diets: 1) a commercial trout feed deprived of the probiotic and 2) the same diet but with the spores of the probiotic bacteria dissolved in fish oil during the manufacturing of the feed (final concentration = 2 × 10(4) cfu/g). Each diet was tested in three 400-L cylindroconical tanks (125 fish per tank; initial density = 1.3 kg/m(3); 13.2°C) for a period of 93 d. The probiotic-supplemented diet promoted growth, and the final mean BW and standard length in fish fed the probiotic were 3.4% and 2.1%, respectively, which was greater than the control group (P < 0.05). Fish fed the probiotic showed a more homogeneous distribution in the final BW, with a greater frequency of individuals around the modal of the normal distribution of the population. This result is of practical importance because homogenous production lots can improve rearing practices, reducing hierarchical dominance situations arising from individuals of larger sizes. In addition, the probiotic-supplemented diet increased the level of leukocyte infiltration in the lamina propria of the intestinal mucosa, the number of goblet cells (P < 0.010), and villi height (P < 0.001) but did not affect villi width. The administration of the probiotic changed the intestinal microbiota as indicated by 16S rDNA PCR-restriction fragment length polymorphism. In this sense, fish fed the probiotic formed a well-defined cluster composed of 1 super clade, whereas compared control fish had a greater degree of diversity in their gut microbiota. These changes in gut microbiota did not affect the specific activity of selected pancreatic and intestinal digestive enzymes. These results indicate that the inclusion of the probiotic bacteria in trout feeds could be beneficial for the host by enhancing its intestinal innate immune function and promoting growth. PMID:23508031

Gisbert, E; Castillo, M; Skalli, A; Andree, K B; Badiola, I

2013-03-18

407

Organization and evolution of the cotG and cotH genes of Bacillus subtilis.  

PubMed

The cotG and cotH genes of Bacillus subtilis encode two previously characterized spore coat proteins. The two genes are adjacent on the chromosome and divergently transcribed by ?(K), a sporulation-specific ? factor of the RNA polymerase. We report evidence that the cotH promoter maps 812 bp upstream of the beginning of its coding region and that the divergent cotG gene is entirely contained between the promoter and the coding part of cotH. A bioinformatic analysis of all entirely sequenced prokaryotic genomes showed that such chromosomal organization is not common in spore-forming bacilli. Indeed, CotG is present only in B. subtilis, B. amyloliquefaciens, and B. atrophaeus and in two Geobacillus strains. When present, cotG always encodes a modular protein composed of tandem repeats and is always close to but divergently transcribed with respect to cotH. Bioinformatic and phylogenic data suggest that such genomic organizations have a common evolutionary origin and that the modular structure of the extant cotG genes is the outcome of multiple rounds of gene elongation events of an ancestral minigene. PMID:21984783

Giglio, Rosa; Fani, Renato; Isticato, Rachele; De Felice, Maurilio; Ricca, Ezio; Baccigalupi, Loredana

2011-10-07

408

The Arthromitus stage of Bacillus cereus: intestinal symbionts of animals.  

PubMed

In the guts of more than 25 species of arthropods we observed filaments containing refractile inclusions previously discovered and named "Arthromitus" in 1849 by Joseph Leidy [Leidy, J. (1849) Proc. Acad. Nat. Sci. Philadelphia 4, 225-233]. We cultivated these microbes from boiled intestines of 10 different species of surface-cleaned soil insects and isopod crustaceans. Literature review and these observations lead us to conclude that Arthromitus are spore-forming, variably motile, cultivable bacilli. As long rod-shaped bacteria, they lose their flagella, attach by fibers or fuzz to the intestinal epithelium, grow filamentously, and sporulate from their distal ends. When these organisms are incubated in culture, their life history stages are accelerated by light and inhibited by anoxia. Characterization of new Arthromitus isolates from digestive tracts of common sow bugs (Porcellio scaber), roaches (Gromphodorhina portentosa, Blaberus giganteus) and termites (Cryptotermes brevis, Kalotermes flavicollis) identifies these flagellated, spore-forming symbionts as a Bacillus sp. Complete sequencing of the 16S rRNA gene from four isolates (two sow bug, one hissing roach, one death's head roach) confirms these as the low-G+C Gram-positive eubacterium Bacillus cereus. We suggest that B. cereus and its close relatives, easily isolated from soil and grown on nutrient agar, enjoy filamentous growth in moist nutrient-rich intestines of healthy arthropods and similar habitats. PMID:9448315

Margulis, L; Jorgensen, J Z; Dolan, S; Kolchinsky, R; Rainey, F A; Lo, S C

1998-02-01

409

Thuricin: the bacteriocin produced by Bacillus thuringiensis.  

PubMed

Bacillus thuringiensis serovar, thuringiensis (HD-2) demonstrated antibacterial activity against 48 of 56 strains of B. thuringiensis and against some other Gram-positive species but not against Gram-negative species. The antibacterial activity was not inducible by mitomycin C or by ultraviolet irradiation, and additional activity was not liberated from cells by sonication. Upon dilution of the antibacterial substance, zones of inhibition diminished without the appearance of plaques. Gel filtration chromatography indicated an Mr greater than 950,000 for the bacteriocin (thuricin) in its native form. The native thuricin was sedimented by ultracentrifugation, but electron microscopy of the pellet failed to reveal phage particles or phage components. Nondenaturing polyacrylamide gel electrophoresis (PAGE) of thuricin demonstrated the association of bacteriocin activity with a protein band which migrated only slightly into a 5% gel. Sodium dodecyl sulfate (SDS)-PAGE of partially purified thuricin revealed five major bands. Thuricin activity was substantially reduced by treatment with chymotrypsin, pronase, subtilisin, trypsin, and heat at 96 degrees C but not by treatment with lysozyme, phospholipase C, papain, peptidase, or organic solvents. It exhibited a bactericidal and bacteriolytic effect on a sensitive strain, B. thuringiensis serovar, canadensis (MF4). Partially purified preparations of thuricin had phospholipase A activity which was adsorbed by sensitive cells but not by cells which were insensitive to thuricin. Antibacterial activity was blocked by preincubation of thuricin with phospholipid. Loss of a 150-mDa plasmid was correlated with loss of thuricin production. PMID:2723445

Favret, M E; Yousten, A A

1989-03-01

410

Identification of an amphioxus intelectin homolog that preferably agglutinates gram-positive over gram-negative bacteria likely due to different binding capacity to LPS and PGN.  

PubMed

Intelectin is a recently described galactofuranose-binding lectin that plays a role in innate immunity in vertebrates. Little is known about intelectin in invertebrates, including amphioxus, the transitional form between vertebrates and invertebrates. We cloned an amphioxus intelectin homolog, AmphiITLN-like, coding 302 amino acids with a conserved fibrinogen-related domain (FReD) in the N-terminus and an Intelectin domain in the C-terminus. In situ hybridization in adult amphioxus showed that AmphiITLN-like transcripts were highly expressed in the digestive tract and the skin. Quantitative real-time PCR revealed that AmphiITLN-like is significantly up-regulated in response to Staphylococcus aureus challenge, but only modestly to Escherichia coli. In addition, recombinant AmphiITLN-like expressed in E. coli agglutinates Gram-negative and Gram-positive bacteria to different degrees in a calcium dependent manner. Recombinant AmphiITLN-like could bind lipopolysaccharide (LPS) and peptidoglycan (PGN), the major cell wall components of Gram-negative and Gram-positive bacteria, respectively, with a higher affinity to PGN. Our work identified and characterized for the first time an amphioxus intelectin homolog, and provided insight into the evolution and function of the intelectin family. PMID:22475783

Yan, Jie; Wang, Jianfeng; Zhao, Yaqi; Zhang, Jingye; Bai, Changcun; Zhang, Changqing; Zhang, Chao; Li, Kailin; Zhang, Haiqing; Du, Xiumin; Feng, Lijun

2012-03-24

411

The RepA_N replicons of Gram-positive bacteria: a family of broadly distributed but narrow host range plasmids.  

PubMed

The pheromone-responsive conjugative plasmids of Enterococcus faecalis and the multiresistance plasmids pSK1 and pSK41 of Staphylococcus aureus are among the best studied plasmids native to Gram-positive bacteria. Although these plasmids seem largely restricted to their native hosts, protein sequence comparison of their replication initiator proteins indicates that they are clearly related. Homology searches indicate that these replicons are representatives of a large family of plasmids and a few phage that are widespread among the low G+C Gram-positive bacteria. We propose to name this family the RepA_N family of replicons after the annotated conserved domain that the initiator protein contains. Detailed sequence comparisons indicate that the initiator protein phylogeny is largely congruent with that of the host, suggesting that the replicons have evolved along with their current hosts and that intergeneric transfer has been rare. However, related proteins were identified on chromosomal regions bearing characteristics indicative of ICE elements, and the phylogeny of these proteins displayed evidence of more frequent intergeneric transfer. Comparison of stability determinants associated with the RepA_N replicons suggests that they have a modular evolution as has been observed in other plasmid families. PMID:19100285

Weaver, Keith E; Kwong, Stephen M; Firth, Neville; Francia, Maria Victoria

2009-01-06

412

Comparison of the immunostimulatory and proinflammatory activities of candidate Gram-positive endotoxins, lipoteichoic acid, peptidoglycan, and lipopeptides, in murine and human cells.  

PubMed

The role of lipopolysaccharide (LPS) in the pathogenesis of Gram-negative septic shock is well established. The corresponding proinflammatory and immunostimulatory molecule(s) on the Gram-positive bacteria is less well understood, and its identification and characterization would be a key prerequisite in designing specific sequestrants of the Gram-positive endotoxin(s). We report in this paper the comparison of NF-kappaB-, cytokine- and chemokine-inducing activities of the TLR2 ligands, lipoteichoic acid (LTA), peptidoglycan (PGN), and lipopeptides, to LPS, a prototype TLR4 agonist, in murine macrophage cell-lines as well as in human blood. In murine cells, di- and triacyl liopopeptides are equipotent in their NF-kappaB inducing activity relative to LPS, but elicit much lower proinflammatory cytokines. However, both LPS and the lipopeptides potently induce the secretion of a pattern of chemokines that is suggestive of the engagement of a TLR4-independent TRIF pathway. In human blood, although the lipopeptides induce p38 MAP kinase phosphorylation and CD11b upregulation in granulocytes at ng/ml concentrations, they do not elicit proinflammatory cytokine production even at very high doses; LTA, however, activates neutrophils and induces cytokine secretion, although its potency is considerably lower than that of LPS, presumably due to its binding to plasma proteins. We conclude that, in human blood, the pattern of immunostimulation and proinflammatory mediator production elicited by LTA parallels that of LPS. PMID:18468694

Kimbrell, Matthew R; Warshakoon, Hemamali; Cromer, Jens R; Malladi, Subbalakshmi; Hood, Jennifer D; Balakrishna, Rajalakshmi; Scholdberg, Tandace A; David, Sunil A

2008-04-18

413

Comparison of killing of gram-negative and gram-positive bacteria by pure singlet oxygen. [Salmonella typhimurium; Escherichia coli; Sarcina lutea; Staphylococcus aureus; Streptococcus lactis; Streptococcus faecalis  

SciTech Connect

Gram-negative and gram-positive bacteria were found to display different sensitivities to pure singlet oxygen generated outside of cells. Killing curves for Salmonella typhimurium and Escherichia coli strains were indicative of multihit killing, whereas curves for Sarcina lutea, Staphylococcus aureus, Streptococcus lactis, and Streptococcus faecalis exhibited single-hit kinetics. The S. typhimurium deep rough strain TA1975, which lacks nearly all of the cell wall lipopolysaccharide coat and manifests concomitant enhancement of penetration by some exogenous substances, responded to singlet oxygen with initially faster inactivation than did the S. typhimurium wild-type strain, although the maximum rates of killing appeared to be quite similar. The structure of the cell wall thus plays an important role in susceptibility to singlet oxygen. The outer membrane-lipopolysaccharide portion of the gram-negative cell wall initially protects the bacteria from extracellular singlet oxygen, although it may also serve as a source for secondary reaction products which accentuate the rates of cell killing. S. typhimurium and E. coli strains lacking the cellular antioxidant, glutathione, showed no difference from strains containing glutathione in response to the toxic effects of singlet oxygen. Strains of Sarcina lutea and Staphylococcus aureus that contained carotenoids, however, were far more resistant to singlet oxygen lethality than were both carotenoidless mutants of the same species and other gram-positive species lacking high levels of protective carotenoids.

Dahl, T.A.; Midden, W.R. (Bowling Green State Univ., OH (USA)); Hartman, P.E. (Johns Hopkins Univ., Baltimore, MD (USA))

1989-04-01

414

Performance of the New VITEK 2 GP Card for Identification of Medically Relevant Gram-Positive Cocci in a Routine Clinical Laboratory  

PubMed Central

The VITEK 2 gram-positive (GP) identification card (bioMérieux, Marcy l'Etoile, France) has been redesigned to achieve greater accuracy in the identification of gram-positive cocci. A total of 43 biochemical tests, including 17 enzymatic tests, are present in the card and interpreted in a kinetic mode, for up to 8 h. The VITEK 2 database, used in conjunction with the GP identification card, allows the identification of 115 different taxa. A total of 364 strains of GP cocci (217 Streptococcaceae strains and 147 Micrococcaceae strains) belonging to 31 taxa were tested with the new VITEK 2 GP identification card. Of the 364 strains, 105 were taken from routine primary plating media. A total of 344 strains (94.5%) were correctly identified to the species level and 17 strains (4.7%) were identified with low discrimination, requiring additional tests, whereas 1 strain (0.3%) was incorrectly identified and 2 strains (0.5%) remained unidentified. Within 7 h of the start of incubation, more than 90% of all strains were identified. Of the 105 primary cultures, 97% were correctly identified to the species level, 2% were identified with low discrimination, and 1% remained unidentified. Identification performance data were independent of each of the three plating media used. It is concluded that the new VITEK 2 GP identification card provides reliable results for the identification of GP cocci under routine laboratory conditions.

Funke, Guido; Funke-Kissling, Pascale

2005-01-01

415

Molecular insights into the initiation of sporulation in Gram-positive bacteria: new technologies for an old phenomenon  

Microsoft Academic Search

The last decade has witnessed extensive, and widespread, changes in scientific technologies that have impacted significantly upon the study of the life sciences. Arguably, the biggest advances in our comprehension of simple and complex biological processes have come as a consequence of obtaining the complete DNA sequence of organisms. It is likely that we will become accustomed to hearing of

Keith Stephenson; Richard J. Lewis

2005-01-01

416

Peptide pheromone-dependent regulation of antimicrobial peptide production in Gram-positive bacteria: a case of multicellular behavior  

Microsoft Academic Search

Quorum sensing enables unicellular organisms to behave in a multicellular way by allowing population-wide synchronized adaptive responses that involve modulation of a wide range of physiological responses in a cell density-, cell proximity- or growth phase-dependent manner. Examples of processes modulated by quorum sensing are the development of genetic competence, conjugative plasmid transfer, sporulation and cell differentiation, biofilm formation, virulence

Michiel Kleerebezem; Luis E. Quadri

2001-01-01

417

Mutational Analysis of Active Site Residues Essential for Sensing of Organic Hydroperoxides by Bacillus subtilis OhrR  

Microsoft Academic Search

Bacillus subtilis OhrR is the prototype for the one-Cys family of organic peroxide-sensing regulatory proteins. Mutational analyses indicate that the high sensitivity of the active site cysteine (C15) to peroxidation requires three Tyr residues. Y29 and Y40 from the opposing subunit of the functional dimer hydrogen bond with the reactive Cys thiolate, and substitutions at these positions reduce or eliminate

S. Soonsanga; M. Fuangthong; J. D. Helmann

2007-01-01

418

Bacillus naphthovorans sp. nov. from oil-contaminated tropical marine sediments and its role in naphthalene biodegradation.  

PubMed

A Bacillus sp., designated as strain MN-003, was isolated as the dominant cultivatable naphthalene-degrading organism from oil-contaminated tropical marine sediments. Strain MN-003 is strictly aerobic, rod-shaped, Gram-positive, catalase positive, oxidase negative, and forms endospores. Strain MN-003 grew at salinities ranging from 0.28 to 7.00% and temperatures ranging from 15 to 41 degrees C. Phylogenetic analyses reveal that strain MN-003 is most similar to Bacillus sp. VAN14, with a 16S rRNA sequence identity of 97.9%. Based on taxonomic and 16S rRNA data, strain MN-003 was named Bacillus naphthovorans sp. nov. When grown with naphthalene as sole carbon source, strain MN-003 had a maximal specific growth rate (mu(max)) of 0.32 +/- 0.03 h(-1), and a half-saturation constant (K(S)) of 22.3 +/-4.2 microM. A batch study of the tropical marine sediments enriched with naphthalene showed that cells of the Bacillus genus grew to become dominant members of the microbial community. The bacilli comprised 39.5 +/- 6.5% of the microbial fraction after 20 days of enrichment. PMID:11954805

Zhuang, W Q; Zhuang, W Q; Maszenan, A M; Tay, S T L

2002-03-01