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Bacteria are single-celled organisms with unique internal structures. Humans and other multicellular organisms are eukaryotes, which means our cells have distinct nuclei bound with a membrane. Bacteria are prokaryotes, meaning they don’t have organized nuclei or any other membrane-bound organelles.

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  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    It is the differential staining techniques which was first developed by Ziehl and later on modified by Neelsen. So this method is also called Ziehl-Neelsen staining techniques. Neelsen in 1883 used Ziehl’s carbol-fuchsin and heat then decolorized with an acid alcohol, and counter stained with methylRead more

    It is the differential staining techniques which was first developed by Ziehl and later on modified by Neelsen. So this method is also called Ziehl-Neelsen staining techniques. Neelsen in 1883 used Ziehl’s carbol-fuchsin and heat then decolorized with an acid alcohol, and counter stained with methylene blue. Thus Ziehl-Neelsen staining techniques was developed.

    The main aim of this staining is to differentiate bacteria into acid fast group and non-acid fast groups.

    This method is used for those microorganisms which are not staining by simple or Gram staining method, particularly the member of genus Mycobacterium, are resistant and can only be visualized by acid-fast staining.

    Principle of Acid-Fast Stain
    When the smear is stained with carbol fuchsin, it solubilizes the lipoidal material present in the Mycobacterial cell wall but by the application of heat, carbol fuchsin further penetrates through lipoidal wall and enters into cytoplasm. Then after all cell appears red. Then the smear is decolorized with decolorizing agent (3% HCL in 95% alcohol) but the acid fast cells are resistant due to the presence of large amount of lipoidal material in their cell wall which prevents the penetration of decolorizing solution. The non-acid fast organism lack the lipoidal material in their cell wall due to which they are easily decolorized, leaving the cells colorless. Then the smear is stained with counterstain, methylene blue. Only decolorized cells absorb the counter stain and take its color and appears blue while acid-fast cells retain the red color.

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  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    Acid-fast stain The acid-fast stain is a laboratory test that determines if a sample of tissue, blood, or other body substance is infected with the bacteria that causes tuberculosis (TB) and other illnesses. How the Test is Performed Depending on where the infection may be in your body, your healthRead more

    Acid-fast stain
    The acid-fast stain is a laboratory test that determines if a sample of tissue, blood, or other body substance is infected with the bacteria that causes tuberculosis (TB) and other illnesses.

    How the Test is Performed
    Depending on where the infection may be in your body, your health care provider will collect one of these samples:

    Urine
    Stool
    Sputum
    Bone marrow
    Tissue
    The sample is then sent to a laboratory. Some of the sample is placed on a glass slide, stained, and heated. The cells in the sample hold onto the dye. The slide is then washed with an acid solution and a different stain is applied.

    Bacteria that hold onto the first dye are considered “acid-fast” because they resist the acid wash. These types of bacteria are associated with TB and other infections.

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bacteriadiagnosisdiseasesmicrobiologytetanus
  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    The diagnosis of tetanus is clinical and does not require a demonstration of C. tetani. Treatment should be started immediately based on clinical diagnosis. Laboratory diagnosis provides supportive evidence for confirmation. Specimen Excised tissue bits from the necrotic depths of wounds are more reRead more

    The diagnosis of tetanus is clinical and does not require a demonstration of C. tetani. Treatment should be started immediately based on clinical diagnosis. Laboratory diagnosis provides supportive evidence for confirmation.

    Specimen

    Excised tissue bits from the necrotic depths of wounds are more reliable than wound swabs.

    Gram staining

    Gram staining reveals gram-positive bacilli with terminal and round spores (drum stick appearance or tennis racket appearance). However, microscopy alone is unreliable as it cannot distinguish C. tetani from morphologically similar non-pathogenic clostridia like C. tetanomorphum and C. sphenoides.
    Culture

    Culture is more reliable than microscopy.

    • Robertson cooked meat(RCM) broth – C. tetani being proteolytic turns the meat particles black and produces a foul odor.

    • Blood agar with polymyxin B: C. tetani produce characteristic swarming growth when incubated at 37°C for 24-48 hours under anaerobic conditions.

    Toxigenicity Test

    As pathogenesis of tetanus is toxin mediated, the association of the isolated organism can only be established when its toxin production is demonstrated. Toxigenicity can be detected by both in vitro and in vivo methods.

    • In vitro hemolysis inhibition test: C. tetani produces hemolysis on blood agar which is inhibited by adding antitoxin. This test indicates the production of tetanolysin only but not tetanospasmin.

    • In vivo mouse inoculation test: RCM broth with black turbid growth is injected into the root of the tail of a test mouse. The test animal develops stiffness which begins with the tail and progresses to involve the hind limbs on the inoculated side- the other limb-trunk-forelimbs. Death occurs within two days. This test indicates the production of tetanospasmin.

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  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    Non-capsulated bacteria are bacteria that lack a capsule. A capsule is a protective outer covering on certain gram-negative and gram-positive bacteria that increases virulence. The capsule acts to prevent desiccation and phagocytosis. Bacteria without a capsule, or non-capsulated bacteria, include NRead more

    Non-capsulated bacteria are bacteria that lack a capsule. A capsule is a protective outer covering on certain gram-negative and gram-positive bacteria that increases virulence. The capsule acts to prevent desiccation and phagocytosis. Bacteria without a capsule, or non-capsulated bacteria, include Neisseria, Corynebacterium, Salmonella, Shigella, Vibrio, Proteus, Pseudomonas.

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  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    The capsule is found most commonly among gram-negative bacteria: Escherichia coli (in some strains) Neisseria meningitidis Klebsiella pneumoniae Haemophilus influenzae Pseudomonas aeruginosa Salmonella However, some gram-positive bacteria may also have a capsule: Bacillus megaterium for example, synRead more

    The capsule is found most commonly among gram-negative bacteria:

    Escherichia coli (in some strains)
    Neisseria meningitidis
    Klebsiella pneumoniae
    Haemophilus influenzae
    Pseudomonas aeruginosa
    Salmonella
    However, some gram-positive bacteria may also have a capsule:

    Bacillus megaterium for example, synthesizes a capsule composed of polypeptide and polysaccharides.
    Bacillus anthracis
    Streptococcus pyogenes synthesizes a hyaluronic acid capsule.
    Streptococcus pneumoniae has at least 91 different capsular serotypes. These serotypes are the basis for the pneumococcal vaccines.
    Streptococcus agalactiae produces a polysaccharide capsule of nine antigenic types that all contain sialic acid (Ia, Ib, II, III, IV, V, VI, VII, VIII).
    Staphylococcus epidermidis
    Staphylococcus aureus

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bacteria
  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the gram-staining method of bacterial differentiation.

    Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the gram-staining method of bacterial differentiation.

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bacteria
  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall.

    In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall.

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bacteria
  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures. Mycobacteria are called acid-fast bacilli because they are a group of rod-shaped baRead more

    Acid-fastness is a physical property of certain bacterial and eukaryotic cells, as well as some sub-cellular structures, specifically their resistance to decolorization by acids during laboratory staining procedures. Mycobacteria are called acid-fast bacilli because they are a group of rod-shaped bacteria (bacilli) that can be seen under the microscope following a staining procedure where the bacteria retain the color of the stain after an acid wash (acid-fast).

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bacteria
  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    Bacterial spores are highly resistant, dormant structures (i.e. no metabolic activity) formed in response to adverse environmental conditions. They help in the survival of the organisms during adverse environmental conditions; they do not have a role in reproduction. Spore formation (sporulation) ocRead more

    Bacterial spores are highly resistant, dormant structures (i.e. no metabolic activity) formed in response to adverse environmental conditions. They help in the survival of the organisms during adverse environmental conditions; they do not have a role in reproduction.

    Spore formation (sporulation) occurs when nutrients, such as sources of carbon and nitrogen are depleted. Bacterial spores are highly resistant to

    Heat
    Dehydration
    Radiation and
    Chemicals.

    Structure of Bacterial Spore:
    An endospore is structurally and chemically more complex than the vegetative cell. It contains more layers than vegetative cells. The resistance of Bacterial spore may be mediated by dipicolinic acid, a calcium ion chelator found only in spores. When the favorable condition prevail, (i.e. availability of water, appropriate nutrients) spores germination occurs which forms vegetative cells of pathogenic bacteria.

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bacteria
  1. Dr Md shahriar kabir B H M S; MPH
    Dr Md shahriar kabir B H M S; MPH Enlightened dr.basuriwala

    Bacteria are microscopic, single-celled organisms that thrive in diverse environments. Bacteria are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometers in length, bacteria have a number of shapes, ranging from spheres to rods and spiraRead more

    Bacteria are microscopic, single-celled organisms that thrive in diverse environments. Bacteria are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometers in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. These organisms can live in soil, the ocean, and inside the human gut.

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