scholarly journals Comparative genomics groups phages of Negativicutes and classical Firmicutes despite different Gram-staining properties

2019 ◽  
Author(s):  
Chris M Rands ◽  
Harald Brüssow ◽  
Evgeny M Zdobnov
Keyword(s):  
Sequence Data ◽  
Cell Structure ◽  
Antibiotic Resistance Genes ◽  
Side Branch ◽  
Outer Cell ◽  
Gram Positive ◽  
Independent Evidence ◽  
Gram Negative ◽  
Gram Staining ◽  
Sequence Relationship

SummaryNegativicutes are Gram-Negative bacteria characterized by two cell membranes, but they are phylogenetically a side-branch of Gram-Positive Firmicutes that contain only a single membrane. We asked whether viruses (phages) infecting Negativicutes were horizontally acquired from Gram-Negative Proteobacteria, given the shared outer cell structure of their bacterial hosts, or if Negativicute phages co-evolved vertically with their hosts and thus resemble Gram-Positive Firmicute prophages. We predicted and characterised 485 prophages from Gram-Negative Firmicute genomes plus 2,977 prophages from other bacterial clades, and we used virome sequence data from 183 human stool samples to provide independent evidence for our predictions. The majority of the identified Negativicute prophages were lambdoids closer related to prophages from other Firmicutes than Proteobacteria by sequence relationship and genome organization (position of the lysis module). Only a single Mu-like candidate prophage and no clear P2-like prophages were identified in Negativicutes, both commonly found in Proteobacteria. Therefore, it is unlikely that Negativicute phages were acquired from Proteobacteria. Sequence-related prophages were identified in two distinct Negativicute orders (Veillonellales and Acidaminococcales) possibly suggesting horizontal cross-order phage infection between human gut commensals. Phages infecting these Negativicute orders occasionally harboured putative antibiotic resistance genes.

scholarly journals Morphological characterization of gram-positive and gram-negative bacteria from treated latex processing wastewater

2021 ◽  
Vol 1 (2) ◽  
pp. 32-36
Author(s):  
Farrah Aini Dahalan ◽  
Nor Azizah Parmin
Keyword(s):  
Oxygen Demand ◽  
Morphological Characterization ◽  
The Other ◽  
Morphological Properties ◽  
Morphological Observation ◽  
Gram Positive ◽  
Bacterial Colony ◽  
Gram Negative ◽  
Gram Staining

A preliminary morphological screening and isolation of bacterial colony from latex industrial wastewater was carried out. Bacteria colonies from latex processing wastewater were isolated from a local latex processing industry. It was found that 17 bacterial isolates had been purified grown on nutrient agar under 35˚C. The colonies were then purified and morphologically indicated via Gram staining and motility test. After morphological observation, it was identified that out of 17 isolates, 9 isolates were Gram positive and 8 isolates were Gram negative. There are 11 out of 17 colonies were rod-shaped bacterial colonies, while the other 6 colonies were cocci-shaped bacteria. There were 11 colonies of gliding bacteria, three colonies were non-motile bacteria and the other three colonies were flagellated bacteria. This study is only limited to morphological observation as the main aim of this study was to investigate the potential occurrence of viable growth in treated latex processing wastewater. The bacterial colonies were classified base on their morphological properties shown. This study has classified several genera such as Staphylococcus, Escherichia, Thiobacillus, Arthrobacter and other Genus. The growth curve of 17 isolates studied and the chemical oxygen demand were determined.

scholarly journals Identification and Characterization of the First Cholesterol-Dependent Cytolysins from Gram-Negative Bacteria

2012 ◽  
Vol 81 (1) ◽  
pp. 216-225 ◽  
Author(s):  
Eileen M. Hotze ◽  
Huynh M. Le ◽  
Jessica R. Sieber ◽  
Christina Bruxvoort ◽  
Michael J. McInerney ◽  
...  
Keyword(s):  
Cell Structure ◽  
Bacterial Species ◽  
Cytolytic Activity ◽  
Opportunistic Pathogens ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Positive Type ◽  
Secretion Signal ◽  
Anaerobic Soils

The cholesterol-dependent cytolysins (CDCs) are pore-forming toxins that have been exclusively associated with a wide variety of bacterial pathogens and opportunistic pathogens from theFirmicutesandActinobacteria, which exhibit a Gram-positive type of cell structure. We have characterized the first CDCs from Gram-negative bacterial species, which includeDesulfobulbus propionicustype species Widdel 1981 (DSM 2032) (desulfolysin [DLY]) andEnterobacter lignolyticus(formerlyEnterobacter cloacae) SCF1 (enterolysin [ELY]). The DLY and ELY primary structures show that they maintain the signature motifs of the CDCs but lack an obvious secretion signal. Recombinant, purified DLY (rDLY) and ELY (rELY) exhibited cholesterol-dependent binding and cytolytic activity and formed the typical large CDC membrane oligomeric pore complex. Unlike the CDCs from Gram-positive species, which are human- and animal-opportunistic pathogens, neitherD. propionicusnorE. lignolyticusis known to be a pathogen or commensal of humans or animals: the habitats of both organisms appear to be restricted to anaerobic soils and/or sediments. These studies reveal for the first time that the genes for functional CDCs are present in bacterial species that exhibit a Gram-negative cell structure. These are also the first bacterial species containing a CDC gene that are not known to inhabit or cause disease in humans or animals, which suggests a role of these CDCs in the defense against eukaryote bacterial predators.

scholarly journals Clots retrieved by mechanical thrombectomy from acute ischemic stroke patients show no evidence of bacteria

2019 ◽  
Vol 25 (5) ◽  
pp. 502-507 ◽  
Author(s):  
Zenith Khashim ◽  
Seán Fitzgerald ◽  
Ramanathan Kadirvel ◽  
Daying Dai ◽  
Karen M Doyle ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Real Time ◽  
16S Rdna ◽  
Mechanical Thrombectomy ◽  
Blood Clot ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Staining

Background Bacteria and bacterial components have been associated with the activation of coagulation factors and initiating the blood clot formation. The aim of this study was to investigate whether bacterial populations are present in clots retrieved from patients that have suffered a large vessel occlusion acute ischemic stroke (AIS). Materials and methods Clot samples were collected from 20 AIS patients who underwent clot retrieval with mechanical thrombectomy. Patient clinical demographic details were noted. Expression of bacterial 16S rDNA was analyzed by standard and real-time polymerase chain reaction (PCR). Gram staining was performed to identify Gram-positive and Gram-negative bacteria. Results Both the real-time and standard PCR demonstrated no expression of 16S rDNA in any of the 20 clots samples from AIS patients. Gram staining results showed no expression of Gram-positive or Gram-negative bacteria present in the clot samples. Conclusion Our current study found no bacteria populations in the clots of AIS patients.

scholarly journals Misinterpretation of Gram Stain from the Stationary Growth Phase of Positive Blood Cultures for Brucella and Acinetobacter Species

2017 ◽  
Vol 11 (1) ◽  
pp. 126-131 ◽  
Author(s):  
Ali M. Bazzi ◽  
Jaffar A. Al-Tawfiq ◽  
Ali A. Rabaan
Keyword(s):  
Real Time Pcr ◽  
Blood Cultures ◽  
Blood Agar ◽  
Gram Stain ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Staining ◽  
Urease Test ◽  
Oxidase Test ◽  
Vitek 2

Introduction:Acinetobacter baumanniiandBrucellaspecies are Gram-negative organisms that are vulnerable to misinterpretation as Gram-positive or Gram-variable in blood cultures.Objective:We assess the random errors in gram stain interpretation to reduce the likelihood of such errors and therefore patient harm.Methodology:Aerobic and anaerobic blood cultures from two patients in an acute care facility in Saudi Arabia were subjected to preliminary Gram-staining. In case 1, VITEK-2 Anaerobe Identification, repeat Gram staining from a blood agar plate, Remel BactiDrop™ Oxidase test, Urea Agar urease test and real-time PCR were used to confirm presence ofBrucellaand absence ofCoryneformspecies. In case 2, repeat Gram- staining from the plate and the vials, VITEK-2 Gram-Negative Identification, real-time PCR and subculture on to Columbia agar, blood agar, and MacConkey agar were carried out to identifyA. baumannii.Results:In case 1, initially pleomorphic Gram-positive bacteria were identified.Coryneformspecies were suspected. Tiny growth was observed after 24 h on blood agar plates, and good growth by 48 h. Presence ofBrucellaspecies was ultimately confirmed. In case 2, preliminary Gram-stain results suggested giant Gram-positive oval cocci. Further testing over 18-24 h identifiedA. baumannii.Conclusions:Oxidase test from the plate and urease test from the culture vial is recommended after apparent identification of pleomorphic Gram-positive bacilli from blood culture, once tiny growth is observed, to distinguishBrucellafromCorynebacteriumspecies. If giant Gram-positive oval cocci are indicated by preliminary Gram-staining, it is recommended that the Gram stain be repeated from the plate after 4-6 h, or culture should be tested in Triple Sugar Iron (TSI) medium and the Gram stain repeated after 2-4 h incubation.

Gram staining v1

2021 ◽  
Author(s):  
lydiariver not provided
Keyword(s):  
Cell Walls ◽  
Group B Streptococcus ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Staining ◽  
Acetone Treatment ◽  
Gram Negative Organisms ◽  
Group B ◽  
Gram Positive Cocci

Gram staining is one of the first techniques used for the identification of group B Streptococcus agalactiae and one would expect to see gram-positive cocci under the microscope. The technique consists of applying a series of colorants and bleaches (acetone), which interact with the lipids of the membranes of gram-positive and gram-negative bacteria. The cell walls of gram-positive organisms retain the dye after acetone treatment and appear purple in color, whereas gram-negative organisms become discolored after acetone treatment and appear pink.

Helcococcus kunzii, a skin-colonising microorganism with pathogenic capacity: a case of polymicrobial intracranial empyema

2021 ◽  
Vol 14 (11) ◽  
pp. e244600
Author(s):  
Margarida Mouro ◽  
João Frade ◽  
Catarina Chaves ◽  
Jorge Velez
Keyword(s):  
Oral Route ◽  
Human Infection ◽  
Gram Positive ◽  
Gram Negative ◽  
Negative Bacillus ◽  
The Third ◽  
Gram Staining ◽  
Intravenous Antibiotics ◽  
Gram Negative Bacillus ◽  
History Of

Helcococcus kunzii is a Gram-positive anaerobic facultative coccus that colonises the skin. Human infection is rare, with very few cases being described in the literature. The authors present the case of a 17-year-old man, with a history of cholesteatoma, diagnosed with mastoiditis complicated by intracranial empyema. After urgent surgical drainage, Gram staining revealed a Gram-negative bacillus and a Gram-positive coccus. The latter exhibited fastidious growth, presented as small grey colonies in blood agar, and was afterwards identified as H. kunzii. The patient was started on intravenous antibiotics, switched to oral route after 8 weeks and fully recovered. To the best of our knowledge, this is the third case of an intracranial infection in which H. kunzii is involved, two of them occurring in patients with cholesteatoma.

scholarly journals A SEMI-MICRO METHOD FOR THE DETERMINATION OF CRYSTAL VIOLET SORBED TO BIOLOGICAL MATERIAL

1958 ◽  
Vol 6 (4) ◽  
pp. 237-243 ◽  
Author(s):  
ROLAND FISCHER ◽  
JERRY ZALESCHUK
Keyword(s):  
Crystal Violet ◽  
Leuconostoc Mesenteroides ◽  
Two Dimensional ◽  
Dye Uptake ◽  
Nerve Fibres ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Staining ◽  
Identical Composition

A semi-micro method is reported to measure the degree of Gram positive behaviour, i.e. the amount of crystal violet sorbed by various proteinous materials. Part of the role supposedly played by "loosely bound" iodine as well as that by covalently bound iodine in the crystal violet uptake of intact wool (Gram negative) and alkali-degraded wool (Gram positive) has been determined. The influence of reversing the consecutive steps of staining and iodination on dye-uptake has been measured for wools. The iodine uptake prior to and after staining, as well as the dye-uptake prior to iodination, have been determined for the two types of wool as well as for Escherichia coli and Leuconostoc mesenteroides respectively. The dye-uptake of wools and of bacteria was also measured after treatment with 1-fluor-2,4-dinitrobenzene. The identical composition in non-sulphur containing amino acids of intact wool and alkalidegraded wool—prior to and after treatment with 1-fluor-2,4-dinitrobenzene—has been investigated by subjecting the wools to hydrolysis and one- as well as two-dimensional paper chromatography. Data are reported as to the crystal violet uptake prior to and after iodination of muscle and nerve-fibres, nail, ovalbumin, β-glucuronidase and pepsin. The theoretical implications of these and other data are discussed and attention is drawn to the manyfold aspects of the problem of Gram staining behaviour of proteins.

scholarly journals Simultaneous Fluorescent Gram Staining and Activity Assessment of Activated Sludge Bacteria

2002 ◽  
Vol 68 (10) ◽  
pp. 4772-4779 ◽  
Author(s):  
Scott Forster ◽  
Jason R. Snape ◽  
Hilary M. Lappin-Scott ◽  
Jonathan Porter
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Flow Cytometric Analysis ◽  
Quantitative Measure ◽  
Bacterial Cells ◽  
Gram Positive ◽  
Gram Negative ◽  
Highly Active ◽  
Gram Staining

ABSTRACT Wastewater treatment is one of the most important commercial biotechnological processes, and yet the component bacterial populations and their associated metabolic activities are poorly understood. The novel fluorescent dye hexidium iodide allows assessment of Gram status by differential absorption through bacterial cell walls. Differentiation between gram-positive and gram-negative wastewater bacteria was achieved after flow cytometric analysis. This study shows that the relative proportions of gram-positive and gram-negative bacterial cells identified by traditional microscopy and hexidium iodide staining were not significantly different. Dual staining of cells for Gram status and activity proved effective in analyzing mixtures of cultured bacteria and wastewater populations. Levels of highly active organisms at two wastewater treatment plants, both gram positive and gram negative, ranged from 1.5% in activated sludge flocs to 16% in the activated sludge fluid. Gram-positive organisms comprised <5% of the total bacterial numbers but accounted for 19 and 55% of the highly active organisms within flocs at the two plants. Assessment of Gram status and activity within activated sludge samples over a 4-day period showed significant differences over time. This method provides a rapid, quantitative measure of Gram status linked with in situ activity within wastewater systems.

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