is borrelia burgdorferi gram positive or negative

by Vicente Kuhlman Published 3 years ago Updated 3 years ago

gram negative

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Is Bacillius subtilis Gram positive or Gram negative?

Bacillus subtilis is a gram-positive bacterium. It has a thick peptidoglycan layer and teichoic acid in its cell wall. A Gram stain test is used to classify bacteria species according to their reactions with various stains/dyes. This test mainly targets the structural characteristics of a bacteria cell wall.

Which Gram negative or Gram positive bacteria more dangerous?

The majority of the WHO list is Gram-negative bacterial pathogens. Due to their distinctive structure, Gram-negative bacteria are more resistant than Gram-positive bacteria, and cause significant morbidity and mortality worldwide.

Is Bacillus megaterium Gram positive or Gram negative?

Bacillus megaterium is a rod-like, Gram-positive, mainly aerobic spore forming bacterium found in widely diverse habitats. With a cell length of up to 4 µm and a diameter of 1.5 µm, B. megaterium is amongst the biggest known bacteria.

Which bacteria are pathogenic Gram positive or Gram negative?

More than good or bad bacteria, researchers have now unveiled that positive and negative bacterium are responsible for periodontitis symptoms -; Gram-positive and Gram-negative, that is.

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Can Borrelia burgdorferi be Gram stained?

When Borrelia burgdorferi is Gram-stained, the cells stain a weak Gram-negative by default, as safranin is the last dye used. Borrelia, like most spirochetes, does have an outer membrane that contains an LPS-like substance, an inner membrane, and a periplasmic space which contains a layer of peptidoglycan.

What type of cell is Borrelia burgdorferi?

The spirochete Borrelia burgdorferi is a tick-borne obligate parasite whose normal reservoir is a variety of small mammals [1]. Whereas infection of these natural hosts does not lead to disease, infection of humans can result in Lyme disease, as a consequence of the human immunopathological response to B.

Are spirochetes bacteria Gram positive or negative?

Spirochetes are gram-negative, motile, spiral bacteria, from 3 to 500 m (1 m = 0.001 mm) long. Spirochetes are unique in that they have endocellular flagella (axial fibrils, or axial filaments), which number between 2 and more than 100 per organism, depending upon the species.

Is Borrelia a burgdorferi cocci?

A description of Borellia burgdorferi (Bb) along these parameters follows: Shape: There are three shapes of bacteria: Round: Cocci, e.g., Pneumonococci Rod-like: Bacilli, e.g., Salmonella Spiral: Spirochete, e.g., Borrelia Bb are spirochetes. Some bacteria have flagella, whip-like tails, that increase their mobility.

What is unique about Borrelia burgdorferi?

Unique Properties Unlike most disease-causing bacteria, Borrelia burgdorferi do not appear to emit a toxin. Instead, the bacteria seems to have a direct interaction with the cell tissues it infects.

Is Treponema pallidum gram positive?

Treponema pallidum is a Gram-negative micro-aerophilic bacterium, 6–20 μm long, 0.1–0.2 μm wide and tightly coiled. The treponemes are motile by three flagella (axial filaments) that wrap around the surface of the organism and are covered by the outer membrane which contains lipopolysaccharide.

Why do spirochetes not Gram stain?

However, due to their small size, Spirochetes cannot be visualized by traditional gram stains combined with light microscopy.

Why does spirochetes not Gram stain?

While spirochetes are generally regarded as Gram negative bacteria, because they have a thin peptidoglycan, Gram staining is not commonly used to stain them. In the process of staining Borrelia burgdorferi, they have been shown to weakly stain Gram-negative.

Which of the following bacteria is gram negative?

Gram Positive vs Gram NegativeGram positive bacteriaGram negative bacteriaBacteria include all staphylococci, all streptococci and some listeria speciesBacteria include enterococci, salmonella species and pseudomonas speciesThick peptidoglycan layerThin peptidoglycan layer4 more rows•Aug 21, 2019

Which of the following bacteria is Gram-positive?

Gram-positive cocci include Staphylococcus (catalase-positive), which grows clusters, and Streptococcus (catalase-negative), which grows in chains. The staphylococci further subdivide into coagulase-positive (S. aureus) and coagulase-negative (S. epidermidis and S.

What are the Gram-negative cocci?

Medically relevant gram-negative cocci include the four types that cause a sexually transmitted disease (Neisseria gonorrhoeae), a meningitis (Neisseria meningitidis), and respiratory symptoms (Moraxella catarrhalis, Haemophilus influenzae).

What phylum is Borrelia burgdorferi in?

Microbiology and Pathogenesis. Borrelia burgdorferi, the causative agent of Lyme disease, belongs to the phylum Spirochaetes. They are helical, irregularly coiled motile bacteria, 10–20 μm in length, 0.2–0.5 μm in width, containing 3–10 spirals. The ends are tapered, with 4–8 flagella at each end, inserted along the long axis.

What is the chemotaxis gene in Borrelia burgdorferi?

Borrelia burgdorferi has a complex chemotaxis signal transduction system with multiple chemotaxis gene homologs similar to those found in Escherichia coli and Bacillus subtilis. The B. burgdorferi genome sequence encodes two cheA, three cheY, three cheW, two cheB, two cheR, but no cheZ genes. Instead of cheZ, B. burgdorferi contains a different CheY‐P phosphatase, referred to as cheX. The multiple B. burgdorferi histidine kinases (CheA1 and CheA2) and response regulators (CheY1, CheY2, and CheY3) possess all the domains and functional residues found in E. coli CheA and CheY, respectively. Understanding protein phosphorylation is critical to unraveling many biological processes, including chemotaxis signal transduction, motility, growth control, metabolism, and disease processes. E. coli, Salmonella enterica serovar Typhimurium, and B. subtilis chemotaxis systems have been studied extensively, providing models to understand chemotaxis signaling in the Lyme disease spirochete B. burgdorferi. Both genetic approaches and biochemical analyses are essential in understanding its complex two‐component chemotaxis systems. Specifically, gene inactivation studies assess the importance of specific genes in chemotaxis and motility under certain conditions. Furthermore, biochemical approaches help determine the following in vitro reactions: (1) the extent that the histidine kinases, CheA1 and CheA2, are autophosphorylated using ATP; (2) the transfer of phosphate from CheA1‐P and CheA2‐P to each CheY species; and (3) the dephosphorylation of each CheY‐P species by CheX. We hypothesize that characterizing protein phosphorylation in the B. burgdorferi two‐component chemotaxis system will facilitate understanding of how the periplasmic flagellar bundles located near each end of B. burgdorferi cells are coordinately regulated for chemotaxis. During chemotaxis, these bacteria run, pause (stop/flex), and reverse (run again). This chapter describes protocols for assessing B. burgdorferi CheA autophosphorylation, transfer of phosphate from CheA‐P to CheY, and CheY‐P dephosphorylation.

What is the spirochete that causes Lyme disease?

Borrelia burgdorferi is a spirochete that causes Lyme disease. It is transmitted to humans and other animals by the bite of a tick and is the most prevalent arthropod borne infection in the United States. As with other spirochete species, B. burgdorferi has a unique structure. Outermost is an outer membrane sheath. This membrane is devoid of lipopolysaccharides. Within the outer membrane sheath is the cell cylinder. Residing in the periplasmic space are 14 to 22 periplasmic flagella, with 7 to 11 periplasmic flagella inserted near each end of the cell that extend toward the cell body center ( Charon and Goldstein, 2002; Rosa et al., 2005 ).

What is the role of Bb lipoproteins in cytokine production?

Bb lipoproteins are believed to play an important role in cytokine dysregulation. Lipoprotein-mediated stimulation of TNF-α (but not IL6) appears to be mediated through a mitogen-activated protein kinase–dependent pathway [ 5 ].

Can Borrelia burgdorferi be transmitted by transfusion?

Borrelia burgdorferi transmission by transfusion has not been widely described. Authors postulate, that is, it due to low bacterial low in infected humans and inability of host-adapted spirochetes to survive under blood storage conditions [ 98 H].

Why is there no response to antimicrobials for lyme disease?

The most common reason for a lack of response to appropriate antimicrobial therapy is misdiagnosis (ie, the patient actually does not have Lyme disease).

What is the most common manifestation of early disseminated Lyme disease in the United States?

The most common manifestation of early disseminated Lyme disease in the United States is multiple EM, which is due to spirochetemic dissemination of the organism that may be related to strain-specific characteristics of the bacteria.

What is the most common vector-borne disease in the United States?

Lyme disease is the most common vector-borne disease in the United States. In the United States, the spirochete Borrelia burgdorferisensu stricto (hereafter termed B burgdorferi) is the only pathogen that causes Lyme disease . However, in Europe and Asia, Borrelia afzelii, Borrelia garinii,and other related species, in addition to B burgdorferi, ...

What is EM in lyme disease?

In the United States, EM (single or multiple) occurs in approximately 90% of patients with Lyme disease. Other common manifestations of early disseminated Lyme disease are cranial nerve palsies, especially facial nerve palsy, and meningitis (sometimes accompanied by papilledema and increased intracranial pressure).

How old is the highest risk for lyme disease?

The reported incidence is highest in children age 5 to 10 years, nearly twice as high as the incidence among adults. Persons with occupational, recreational, or residential exposure to tick-infested fields, yards, or woodlands in endemic areas are at increased risk of developing Lyme disease. Open in a separate window.

Where does lyme disease occur?

Most cases of Lyme disease in the United States occur in New England, the Mid-Atlantic states, Wisconsin, and Minnesota (Figure 1). It also occurs, although much less frequently, on the Pacific Coast, primarily in Northern California and Oregon.

Is lyme disease uncommon in the Pacific?

Lyme disease is uncommon in the Pacific states because few I pacificusticks are infected with B burgdorferi. By contrast, in highly endemic areas of Southern New England, approximate rates of infection of I scapularisare 20% to 30% for nymphs and 30% to 50% for adult ticks.

Definition

Borrelia burgdorferi is a spiral-shaped (spirochete) bacterium that is endemic in North America and Europe. It is neither gram negative nor gram positive, and it is most commonly known as the causative agent of Lyme disease.

Microbiology

Borrelia burgdorferi is a spiral-shaped, microaerophilic two-membrane bacterium that is primarily extracellular. B. burgdorferi is one of the few pathogenic bacteria that can survive without iron, instead requiring manganese for proper function of some of its enzymes.

Transmission and Life Cycle

The bacterium is predominantly transmitted to humans by the Ixodes tick, and these ticks, typically in...

Keywords

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What are the 31 and 34 kDa bands in immunoblots?

4.2). It has been recognized since the early 1990s that antibodies to OspA and OspB are infrequently detected and when they are observed, it is usually in patients with longstanding Lyme arthritis. Ma et al. (1992) wrote that ‘…antibodies against the 31- and 34-kDa proteins were rarely detected and, consequently, became less signiﬁ cant when compared with other protein bands in this study’. Steere’s laboratory reported in Dressler et al. (1993) that, although antibodies to OspA and OspB were detectable in some patients with Lyme arthritis or late neurological disease, the frequency of antibody responses to these polypeptides was not as high as to ten other antigens. Blot interpretation criteria that could best discriminate Lyme disease patients from controls therefore did not include scoring antibodies to OspA or OspB. When bands at 31 or 34 kDa are observed, they are virtually always in the context of a robust IgG response to a large number of scored antigens.Patients may inquire speciﬁ cally about why OspA is not scored when it was the basis for an eﬀ ective vaccine (ILADS, 2010). People naturally think of the usual way that vaccines work, neutralizing infection in a mammalian host, and expect a vaccine antigen to be a good diagnostic antigen. They may be unaware that the OspA vaccine works by killing B. burgdorferi in vector ticks as they feed (de Silva et al., 1996). OspA is well expressed by B. burgdorferi in unfed ticks and is a suitable target for antibodies that enter a tick during a blood meal from an OspA-vaccinated host. When ticks are exposed to a blood meal and the body temperature of a mammal, B. burgdorferi stops expressing OspA (Schwan and Piesman, 2000). Another outer-surface protein, OspC, is expressed instead. Reciprocal expression of these two Osps has been demonstrated at the level of single cells (Srivastava and de Silva, 2008). It is not surprising, therefore, that antibody responses to OspC are diagnostically useful in early Lyme disease, but responses to OspA are lacking.

What is the only test for lyme disease?

Serology is the only standardized type of laboratory testing available to support the clinical diagnosis of Lyme borreliosis (Lyme disease) in the USA. It is also the only type of diagnostic testing approved by the US Food and Drug Administration (FDA). Of the 77 devices cleared by the FDA for in vitro diagnostic use for Lyme disease, all are designed to detect immune responses to antigens of Borrelia burgdorferi sensu stricto, particularly IgM and IgG (FDA, 2010). Serological tests do not become positive until an infected individual has had time to develop antibodies. In Lyme disease, this means that early acute disease characterized by an expanding rash (erythema migrans or EM) at the site of a tick bite cannot be reliably diagnosed by serology. Aft er a few weeks of infection, however, immunocompetent people will have made enough antibodies that serology is useful for conﬁrming exposure to B. burgdorferi in all subsequent stages of Lyme disease. Antibody levels remain elevated for months to years aft er the in fection is cured.

What are the two types of direct assays for lyme disease?

These assays are culture of B. burgdorferi and detection of DNA by molecular methods (PCR or quantitative real-time PCR). Neither culture nor PCR are components of the routine evaluation of patients with suspected Lyme disease and no nationally standardized or FDA-approved tests are available. Both techniques have played important roles in understanding the pathogenesis of B. burgdorferi infections, however, and have assisted investigators in establishing serum banks from authenticated Lyme disease patients.

Can lyme disease be tested without objective signs?

Laboratory testing of patients without objective signs of Lyme disease or a history of potential exposure to infected vector ticks is not clinically useful. Laboratory diagnostic tests with excellent sensitivity and speciﬁ city will not have helpful predictive values if they are used inappropriately (Sackette al., 1991). Predictive value is determined both by test characteristics (sensitivity and speciﬁ city) and, importantly, by the population in which it is used. The practice of testing patients with a low likelihood of Lyme disease can generate more false-positive results than true-positive results, resulting in mis-diagnosis and thereby harming ill people (Seltzer and Shapiro, 1996; Tugwell et al., 1997).

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