what is the morphology of neisseria

MORPHOLOGY OF NEISSERIA GONORRHOEAE (GONOCOCCUS) Shape – Neisseria gonorrhoeae is an oval or spherical (coccus) shape bacterium with the adjacent side Concave. Size – The size of Neisseria gonorrhoeae is about 0.6 – 1.0 µm (micrometer) in diameter.

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What are the characteristics of Neisseria?

May 12, 2018 · MORPHOLOGY OF NEISSERIA MENINGITIDIS (MENINGOCOCCUS) Shape – Neisseria meningitidis is an oval or spherical (coccus) shape bacterium with the adjacent side flattened. Size – The size of Neisseria meningitidis is about 0.6 µm – 0.8 µm (micrometer). Arrangement Of Cells – Neisseria meningitidis is arranged in pairs (diplococci), with the …

What is the morphology of Neisseria gonorrhoeae?

May 22, 2018 · MORPHOLOGY OF NEISSERIA GONORRHOEAE (GONOCOCCUS) Shape – Neisseria gonorrhoeae is an oval or spherical (coccus) shape bacterium with the adjacent side Concave. Size – The size of Neisseria gonorrhoeae is about 0.6 – 1.0 µm (micrometer) in diameter. Arrangement Of Cells – Neisseria gonorrhoeae is arranged in singly or in pairs …

What is the shape of Neisseria meningitidis?

Apr 16, 2020 · Neisseria diplococci resemble coffee beans when viewed microscopically. Thereof, what is the morphology of Neisseria meningitidis? N. meningitidis are gram-negative, coffee-bean shaped diplococci that may occur intracellularly or extracellularly in PMN leukocytes.

Is Neisseria a mucous membrane?

Nov 20, 2020 · Morphology of Neisseria gonorrhoeae: Under the microscope, it appears as a gram-negative coccus which is present in pairs (diplococci) with the flattening of the adjacent sides. The diameter ranges from 0.6-1 μm. The diplococci have kidney/coffee bean shape. It is a non-spore forming bacteria and is able to move using twitching motility.

What is the shape of Neisseria gonorrhoeae?

Shape – Neisseria gonorrhoeae is an oval or spherical (coccus) shape bacterium with the adjacent side Concave.

How are Neisseria gonorrhoeae arranged?

Arrangement Of Cells – Neisseria gonorrhoeae is arranged in singly or in pairs (diplococci), with the adjacent side Concave and they are usually present intracellularly when direct microscopic examination of the specimen from the lesions is carried out.

What media is used for gonorrhoeae?

⇒ There are various culture media used for the cultivation of N. gonorrhoeae (Gonococcus) in the laboratory and most commonly the Blood Agar and MHA medium is used, the other media are as follows –

What is the shape of a bacterium?

Shape – Neisseria gonorrhoeae is an oval or spherical (coccus) shape bacterium with the adjacent side Conca ve. Size – The size of Neisseria gonorrhoeae is about 0.6 – 1.0 µm (micrometer) in diameter. Arrangement Of Cells – Neisseria gonorrhoeae is arranged in singly or in pairs (diplococci), with the adjacent side Concave ...

Is N. gonorrhoeae a bacterium?

Capsule – N. gonorrhoeae is a capsulated bacterium and is present in such a way that a capsule encloses each pair of cocci. The capsule can easily be demonstrated using India ink preparation, which appear as a clear halo in a dark background.

What is the colonial morphology of Neisseria gonorrhoeae?

Colonial morphology of Neisseria gonorrhoeae: In a humid aerobic environment enriched with 5-10% CO 2, colonies are thin, round, translucent, convex or slightly umbonate, with finely granular surface and lobate margins after incubation for 24 hours. The colonies of Neisseria gonorrhoeae are pinkish brown.

What agar to grow Neisseria?

They grow rapidly on chocolate agar and Mueller-Hinton agar. The Thayer-Martin medium (chocolate agar containing antimicrobials such as vancomycin, colistin and nystatin) is a common selective medium that inhibits most contamination, including nonpathogenic Neisseria.

What is the diameter of a diplococcus?

The diameter ranges from 0.6-1 μm. The diplococci have kidney/coffee bean shape. It is a non-spore forming bacteria and is able to move using twitching motility. Gonococci exhibit pili on their surface. Pili enhances the binding of the cocci to the mucosal surfaces and promotes virulence by restricting phagocytosis.

What is the name of the genus of gonococcus?

Neisseria gonorrhoeae; commonly termed as gonococcus (gonococci in plural). In 1879, the gonococcus was first described by Neisser in gonorrheal pus. Members of the genus Neisseria dominate the mucous membranes of human and other animals.

How many types of gonococci are there?

Types of gonococci: On the basis of colonial appearance, auto-agglutinability and virulence, Kellogg classified gonococci into four types (T1-T4). T1 and T2 form small brown colonies and possess several numbers of fimbriae (pilated types P1 and P2). They are virulent and auto-agglutinable.

How long can pus be in linen?

Organisms can remain viable in pus-contaminating linen or other fabrics for a day or so.

Which penicillin resistant bacteria do not produce -lactamase?

Isolation of penicillin resistant N. gonorrhoeae that do not produce β-lactamase have been carried out.

What is the size of a Neisseria spp.?

Neisseria spp. are a Gram-negative non-spore-forming diplococcus that has a flattened shape; its size ranges between 0.6–0.8 μm. They are oxidase-positive, non-acid-fast cocci or plump rods. They can reach a diameter of around 0.6–0.8 μm and sometimes up to 1.0 × 2.0–3.0 μm. The cocci often occur in pairs with adjacent sides flattened, giving them a typical kidney-bean shape. They are non-motile aerobes and some are microaerophilic or facultative anaerobes. They are non-halophilic; some have an optimal growth temperature of around 37°C. They need blood or ascitic fluid for growth as well as increased carbon dioxide pressure. Neisseria spp. have a very well-advanced functioning tricarboxylic acid cycle with the ability to use Enter–Doudoroff and pentose shunt. The Embden–Meyerhof (EM) enzymes are present, but this pathway is not extensively used and probably not used at all in aerobic conditions. Fermentation of sugars will mainly result in acid formation from glucose; however, some strains have the ability to produce acids from other sugars.

What is the DNA composition of Neisseria spp?

Genetically the DNA composition is made up from 49–56 mol% from guanine + cytosine (G+C). Genetic studies have shown that a relationship does exist between Neisseria spp., especially between N. meningitidis and N. flavescens; in certain condition N. flavescens can cause meningitis which cannot be treated in the usual manner. N. flavescens was isolated from food and dairy products: it is possible that it is a mutant form of N. meningitidis which can cause meningitis. This genetic analysis is being used as the most certain method to confirm where bacterial types belong to a specific family, it is somewhat more accurate than other procedures.

How long does it take for Neisseria to grow?

are fastidious. Blood agar and chocolate medium (blood heated at 176–194°F/80–90°C) are suitable growth media. Bacterial colonies usually appear after 24–48 hours of growth. Colonies of N. gonorrhoeae are 0.5–1 mm in size. Colonies of N. meningitidis are usually larger (1–2 mm) and flatter. Colonies of the nonpathogenic Neisseria spp. are similar in size, appearance and consistency, except for the saccharolytic Neisseria spp. ( N. subflava, N. sicca and N. mucosa) that are larger (1–3 mm), more convex and smooth ( N. mucosa ). Colonies of N. subflava and N. sicca are opaque and have varying consistency. N. sicca adhere to the agar surface and become wrinkled with prolonged incubation. Some nonpathogenic Neisseria spp. form a yellow pigment ( N. flavescens) or a greenish-yellow pigment ( N. mucosa, N. subflava ).

What temperature does Neisseria grow?

Neisseria spp. grow best aerobically in an atmosphere containing 5–10% carbon dioxide at a temperature of 89.6–98.6°F (32–37°C) and a pH of 7–7.5. Cell size ranges from 0.6 to 1.5 mm depending upon the species source of the isolate and the age of the culture.

Why do Neisseria produce endotoxins?

Some Neisseria produce endotoxins due to the presence of lipo-oligosaccharides and proteins in their outer membranes.

Which colony is larger, N. meningitidis or N. mucosa?

Colonies of N. meningitidis are usually larger (1–2 mm) and flatter. Colonies of the nonpathogenic Neisseria spp. are similar in size, appearance and consistency, except for the saccharolytic Neisseria spp. ( N. subflava, N. sicca and N. mucosa) that are larger (1–3 mm), more convex and smooth ( N. mucosa ).

What is the shape of cocci?

The cocci often occur in pairs with adjacent sides flattened, giving them a typical kidney-bean shape. They are non-motile aerobes and some are microaerophilic or facultative anaerobes. They are non-halophilic; some have an optimal growth temperature of around 37°C.

What is the meaning of the word "neisseria"?

1. Meaning of Neisseria: Neisseria is Gram-negative coccus arranged in pairs with long axes parallel and is strictly a human parasite. Neisseria gonorrhoeae (gonococcus) and N. meningitidis (meningococcus) are the two principal human pathogens. 2.

How many OPa are expressed in one strain of N. gonorrhoeae?

Not more than 3 Opa are expressed by one strain of N. gonorrhoeae, though every strain has about 10 genes for the expression.

How many proteins does Gonococcus have?

Extends through the cell membrane and forms pores on the surface. Each strain of gonococcus possesses only one type of protein I; 18 serovars of Type I A and 28 servoars of type I B have been demonstrated by serotyping of protein I. Through the pores, some nutrients enter the cell. Molecular weight of por protein is 34, 00 to 37,000 Daltons.

What proteins do gonococci produce?

They are poorly defined proteins. Gonococci produce Ig AI proteases which split and inactivate Ig AI. Lip (1-18) and Fbp (iron binding protein) are two other proteins. Their role in the pathogenesis is not yet established.

What is the diameter of a hairlike structure?

These are hair like structures extending from the surface and measures about 7 mm in diameter. They are seen on the surface of fresh isolates. The piliated organisms produce altered appearance of colonies on culture media with sharply defined borders.

Where does periurethral abscess spread?

The infection spreads to the prostate, seminal vesicle and epididymis. The periurethral tissue is also infected—causing a periurethral abscess and structure.

Is a liquid probe system as sensitive as an ELISA system?

A liquid probe system with chemiluminescent detection system for direct detection of gonococci in the general specimens is equally sensitive as that of ELISA system.

What are the virulence factors of N. meningitidis?

Once colonized, it possesses several virulence factors that aid in its invasion and infection of humans: capsule, pili, opacity proteins, meningococcal serine protease A (MspA), lipo-oligosaccharide (LOS), and human factor H-binding protein. Although N. meningitidis may or may not have a capsule, systemic infection isolates are invariably capsulated, aiding in surviving the immune response. The pili are considered a primary adhesion factor and have increased traversal of the nasopharyngeal epithelium in transgenic mice leading to increased rates of meningitis and septicemia. Opacity protein s, Opa and Opc, also facilitate adhesion to and invasion via receptors found on human epithelial cells, endothelial cells, and cells belonging to the immune system. MspA may also aid epithelial and endothelial cell binding. After N. meningitidis invades the bloodstream, it activates and produces a robust immune response. LOS is an essential component for eliciting the immune response, and via cytokine release leads to endothelial damage, capillary leakage, tissue necrosis, organ failure, and meningococcal sepsis.  Human factor H-binding proteins also aid in surviving a strong immune response by binding human factor H and negatively regulating the complement pathway of the immune system. The invasion of the bloodstream is thought to be the primary route to the brain but can also cross the cribriform plate of the ethmoid bone. [7][8]

What is the name of the bacteria that causes a multitude of illnesses?

It is a human-specific bacterium that causes a multitude of illnesses, collectively termed meningococcal disease . Surprisingly, up to 10% of the general population carry the bacteria in their nose and throat without any adverse effects.[2] . Neisseria meningitidis is associated with many infections.

How long does it take for a person to show symptoms of meningococcal infection?

People who come in close contact with meningococcal infected patients can become infected and show symptoms within ten days after initial contact. Close contact refers to proximity less than 3 feet for greater than 8 hours (e.g., family members, roommates, military recruits, daycare centers). Those who are exposed to the patients oral (e.g., kissing) or respiratory secretions (e.g., intubation, suctioning, passengers close on a long flight) are also at risk. If recognized, antimicrobial chemoprophylaxis should commence. Due to the high efficacy in chemoprophylaxis, strongly consider this in patients if there is questionable close contact. Several options are available and include ceftriaxone, rifampin, and ciprofloxacin. [5]

How long does it take for a person to show symptoms after contact with a meningococcal?

Pearls and Other Issues. People who come in close contact with meningococcal infected patients can become infected and show symptoms within ten days after initial contact. Close contact refers to proximity less than 3 feet for greater than 8 hours (e.g., family members, roommates, military recruits, daycare centers).

What is the main serotype in Europe?

Serotypes B and C are the main serotypes in Europe and the Americas and serotype Y, generally causing infection in the United States and Canada. Serotype W is the cause of epidemic outbreaks around the world and had an association with the Hajj pilgrimages to Saudi Arabia.

How long does it take for a nasopharynx to incubate?

meningitidiscolonization of the nasopharynx via inhalation of aerosolized particles containing the bacteria. The incubation period varies and ranges from 1 to 14 days.

Can colonization of the nasopharynx cause infection?

Humans so colonized may be asymptomatic carriers.  Colonizing the nasopharynx puts close contacts, such as family members, college roommates, and military recruits at an increased risk of contracting N. meningitidis and possible infection.

Can enzyme substrate test be used for Neisseria spp?

Although enzyme substrate tests are intended to be used only for the identification of Neisseria spp. isola ted on selective media for N. gonorrhoeae, isolates of other Neisseria spp. are gamma-glutamylaminopeptidase-positive in this test as are isolates of N. meningitidis. Thus, additional tests must be performed to differentiate between these species.

Can Neisseria be misidentified?

Neisseria species may be misidentified as N. meningitidis in acid detection tests. Supplemental tests may be used to differentiate between them.