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Unlock the secrets of Micro-organisms with our exclusive Microbiology Notes, carefully tailored for nursing students and students in grades 10 to 11. Dive into the captivating world of these tiny but mighty life forms, which have a profound impact on our everyday lives. Why Choose Our Microbiology Notes? Comprehensive Coverage: Our notes provide a thorough exploration of Micro-organisms, including bacteria, viruses, fungi, and protozoa. Clarity and Precision: We've distilled complex concepts into easy-to-understand language, perfect for students and aspiring nurses. Real-World Relevance: Learn how Micro-organisms are integral to healthcare, infection control, and patient well-being. Engaging Visuals: Visual aids and illustrations enhance comprehension and retention. Nursing Insight: Discover the nursing perspective on dealing with Micro-organisms in healthcare settings. Whether you're a future nurse aiming to excel in your studies or a curious learner eager to grasp the hidden world
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A Micro-Organism or Microbe is an Organism of Microscopic Size, which may exist in its single celled form of as a colony of cells.
The Micro-Organism can be classified on the basis of the Cellular Structure into the Following 2 Categories. i.e. Cellular Micro-Organism Acellular Micro-Organisms
Microbes that Posses a Cellular Structure in either the Unicellular or the Multicellular Forms. They have a cell as the Basic Unit of their Body Organization. Ex. Bacteria ,Fungi, Protozoa Helminths
the Cellular Structure in any Form and are Without any types of Cells.
The Micro-Organism can be categorized Broadly into the Following Individualized types Bacteria Viruses Fungi Protozoan Algae
The Study of Bacteria is Known as Bacteriology. Bacteria are Small Single – Celled Organisms. Bacteria are Found Almost Everywhere on Growth & are Vital to the Planet’s Ecosystems. Bacteria are the Widely Distributed, Very Small, Microscopic, Unicellular, Prokaryotic Microbes that have immense impact of their presence on Earth. Some Bacteria Cause disease. Ex. Salmonella Typhi (Typhoid) Mycobacterium Tuberculosis (Tuberculosis)
VIRUSES These are that Acellular which are smaller in Size than Bacteria. They are Ultramicroscopic in Nature. Viruses are Responsible for causing the various Viral Diseases in plants & Animals. Ex. HIV (AIDS), SARS-CoV2 (Covid-19) FUNGI The Fungi are the Eukaryotic, Unicellular or Multicellular Microbes. They are usually Larger in Size than the Bacteria. The Fungi can be Pathogenic or Non-pathogenic. The Fungi can have two Morphological Types
C) VIBRIO’S They are comma shaped curved Rods. Ex. Vibrio Comma D) SPIRILLA They are longer Rigid Rods with Several Curved or Coils. They have a helical Shaped and Rigid Body. Ex. Spirillum Ruprem E) SPIROCHETES They are Slender & Flexous Spiral Forms. F) ACTINOMYCETES The Characteristics shape is due to the presence of Rigid Cell wall. Ex. Streptomyces. They are Branching Filamentous Bacteria Ex. Streptomyces Species G) MYCOPLASMA They are cell wall Deficient Bacteria & hence do Not posses Stable Morphology. They occur as Round or Oval Bodies with interlacing Filaments.
BACTERIAL STRUCTURES
Capsulated Bacteria Produces Smooth Colonies and Non Capsulated Bacteria Produces Rough Colonies on the Surface of Agar Media. FUNCTION They Protect the cell From Drying. They Protects the Bacterial Cell Against Anti-Bacterial Agents & Phages.
Cell wall is Involved in Growth & Cell Division of Bacteria. It Gives shape to the Cell. It gives Protection to internal Structure and Acts as Supporting layer. To Prevent Rupture of Bacteria caused by Osmotic pressure differences b/w intra cellular and Extra Cellular Environment. To provide support for flagella. It serves as the sites of Attachment for most Bacterial Viruses.
Ribosomes are the Centre of Protein Synthesis. They are slightly smaller than Eukaryotic Ribosomes. The Sedimentation Constant is 70s. This 70s Ribosomes are made up of two Subunits Namely a large Subunits 50s and a small subunit 30s. During Active protein synthesis the Ribosomes are associated with Mrna and Such Associations are called Polysomes.
The normal flora of the human body refers to the microbial community that colonizes on the skin and mucus membrane. Normal flora is sometimes called indigenous microbiota, as they reside within or on the human’s skin surface. DEFINITION The normal flora merely refers to the population of microorganisms like bacteria, fungi and few protists, which typically colonize at the specific anatomical sites of the human body. The surface tissues (skin and mucus membrane) of the human body are generally non-sterile.
The human microbiota is primarily classified into two groups:
They are fixed-type of microorganisms, which are generally non- pathogenic. Resident microflora confines permanently to the skin’s deeper areas. They can re-establish themselves if disturbed. They cannot be flushed off from the anatomical site. Resident flora is not associated with disease transmission.
They are indeterminate-type of microorganisms, which can be non- pathogenic or potentially pathogenic. Transient microflora confines temporarily to the skin’s superficial layers for hours, days or weeks. They cannot re-establish themselves. They can be flushed off from the anatomical site. Transient flora is closely associated with disease transmission, as they serve as opportunistic microorganisms derived from the environment.
Starting with the external surfaces, the skin harbours 1000 to 10, microorganisms per square centimetre. A human skin layer possesses the outermost epidermis and inner dermis layer. Many bacterial species exist on the skin’s epidermis layer , which does not penetrate until there is no cut or abrasions over the skin surface. Skin is the largest organ exposed to the environment, and it daily counters with a large number of microbes. Factors like skin’s dryness, low pH and secretion of inhibitory substances discourage microbial colonization. The dry skin restricts microbial growth, as the condition is not favourable to them. The moist regions like groin area possess more normal flora (>10,000). The skin has a normal pH between 3 - 5 that also restrict microbial growth.
inhibitory substances that discourage bacterial growth.
The membrane that constitutes the lining of eyelids and eyeball is termed eye conjunctiva. It is a very delicate membrane, which contains sparse microflora due to the following factors: Due to the high moisture content or continuous flow of tears by the eye’s blinking action , the membrane eliminates the microorganisms. The lachrymal secretions include lysozymes that also lyse the microbial cells.
It provides a favourable environment for bacterial growth due to adequate moisture content and dissolved food particles.
To know the intestinal microflora, we need to study all the components of the intestinal tract. Stomach It receives numerous microorganisms from the oral cavity or nasopharynx. The stomach destroys the microbial cells by providing an acidic environment through the secretion of gastric juices (HCl). Lactobacilli and Candida species are evidently seen in the stomach.
The duodenum portion possesses gram-positive cocci and bacilli. Jejunum portioninhabits Enterococci , Lactobacilli , Diphtheroids and Cand ida species. Ileum occupies a large number of anaerobic bacteria and the members of Enterobacteriaceae.
It has a vast number of microbes, and the faecal matter comprises nearly a hundred billion bacteria per gram wet weight. Thus, a large intestine removes a large number of the microbial population through the peristaltic movement of the villi. Mucus in the large intestine plays a critical role in the removal of microorganisms. The microbial flora, along with the faecal matter, adheres with the mucus layer and consequently rolls up into small masses. At last, the microorganisms in the faeces leave the large intestine by passing through the anus. Bacteroides , Fusobacterium , Bifidobacterium , Eubacterium , and Lactobacillus species are the anaerobes that commonly inhabit the large intestine. Escherichia , Proteus , Klebsiella and Enterobacter species are the facultative anaerobes that reside in the colon. Yeasts ( Candida species ) and protozoan ( Trichomonas hominis ) inhabits the cecum region. Commensals like Entamoeba, Endolimax and Iodamoeba species also reside within the colon. A breastfed and bottle-fed infants have gram-positive bacteria in their intestine until they substitute a liquid food by solid food. Thus, gram- negative bacteria (Bacteroides species) predominate in the intestinal flora of the adult-type diet.
The excretory system (kidneys, ureters and urinary bladder) is generally sterile, except for the urethra. The urethra of both males and females inhabit Staphylococcus epidermidis , Streptococcus faecalis , Corynebacterium and Neisseria species are significantly present. Afemale vagina inhabits Lactobacilli , Enterococci , Diphtheroids and Candi da albicans. BENEFICIAL EFFECTS The normal flora is associated with the synthesis of vitamin-B complex and vitamin-K. The colonization of the normal flora on the skin prevents the proliferation of pathogenic microbes, as they compete for the same nutrients. They augment the defence mechanism of the human body or elevate the immune system. Microorganisms produce some antibiotic-like substances. For example, bacteria produce bacteriocins. HARMFUL EFFECTS The consequence of opportunistic pathogens causes disease in an immuno-suppressed person. Some microflorae are drug-resistant. A few microflorae may cause confusion in a disease diagnosis.
The normal flora serves as antigens, which can significantly induce an antibody-mediated immune response. Other bacteria compete with the normal flora of the human body to invade the nutrients of the host. Any disturbances in the normal flora population make the host cell susceptible to pathogens. Therefore, the study of normal microflora gives us a better understanding of the infections to the specific site. The source of infection can also be determined. We can study the medically important microorganisms excised from the infection site. In simple words, the normal flora of the human body influences the host cell susceptibility and morbidity. (C) PATHOGENESIS & COMMON DISEASES PATHOGENESIS Pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. STAGES 4 stages (1) implantation of virus at the portal of entry (2) local replication
TYPES OF MICROSCOPES The Microscope can be of the following types :- (A) Based Upon the Number of Lenses Used I. Simple Microscope II. Compound Microscope (B) Based Upon the Illuminating Source Used I. Light Microscope II. Electron Microscope (C) Based Upon the Number of Eye Piece Objectives Used I. Monocular Microscope II. Binocular Microscope (A)BASED UPON THE NUMBER OF LENSES USED I. SIMPLE MICROSCOPE: - It is the Microscope in which only one lenses is used. e.g., Magnifying Glass. II. COMPOUND MICROSCOPE: - It is the Microscope in which more than one lens are used. e.g., Compound Light Microscope, Electron Microscope. (B)BASED UPON THE ILLUMINATING SOURCE USED I. LIGHT MICROSCOPE: - This is the Simple or Compound Microscope in which light is used as the illuminating source for seeing the image of the microscope object under microscope. e.g., Bright Field Microscope, Dark Field Microscope, Phase Contrast Microscope and Fluorescent Microscope. II. ELECTRON MICROSCOPE This is the Compound Microscope in which the Electron’s Beam is used as the Illuminating source for seeing the image of the microscopic object under the microscope which has greater magnification and resolution than a light microscope. (C)BASED UPON THE NUMBER OF EYE PIECE OBJECTIVES USED I. MONOCULAR MICROSCOPE It has a Single eye piece objective. II.BINOCULAR MICROSCOPE It has two eye piece objectives.
E) MECHANICAL STAGE The slide holding the specimen is put on the stage and moved with the help of the Rotating knobs. F) CONDENSER The condenser lies just below the stage and illuminates the specimen by controlling the quality of light penetrating the specimen from below. G) MIRROR The Mirror is two - sided that helps reflect the natural light by its concave side surface and the artificial light by its plain side surface. It is present on the base of the microscope. H) FOCUSING KNOBS The focusing knobs are of two types, i.e. coarse and fine knobs that helps to adjust the distance between the objective and the specimen slide. The coarse knob helps adjust the view field while the fine knobs ensures a better view of the specimen field. FUNCTION /USE OF MICROSCOPE To magnify Small Objects. To observe an object at the cellular level. It allowing scientists to see the shape of a cell, its nucleus, mitochondria and other organelles. To resolve, or distinguish, fine detail which our eyes alone cannot perceive. To Examine Objects that are too small to be seen by the Naked Eyes. HANDLING OF MICROSCOPE The table on which the microscope is installed must be levelled, sturdy and with appropriate height. Any liquid spills must be avoided on or near the microscope. The light source must be appropriate arranged.
It is like Nutrient Broth consist of peptone ,Meat Extract, Sodium Chloride and water. Nutrient Agar Made by adding 2% Agar in Routine Diagnostic Laboratories. These media support Growth of most Bacteria. Ex. Nutrient Broth =Peptone Water (1%Peptone+ 0.5 Nacl)+100ml water+1% Meat Extract. USES To Grow Non-Fastidious Micro-Organism.
These Media has additional Special Ingredients that are Required for the growth of or for Bringing out certain characteristics of certain bacteria. Media that contain some ingredients of unknown chemical composition are complex media. USES To Cultivate all the Fastidious Organisms.
These media are prepared from pure chemical substances and the exact composition of the Medium is known. Typically they contain a simple sugar as the carbon and energy source, an inorganic Nitrogen source, Various Mineral salts and if Necessary Growth Factors. Ex. Purified Amino Acids, Vitamins, Purines & Pyrimidines.
In these media, Substances such as Blood , Serum or Egg are Added to a basal Medium. They are used to grow bacteria which are more fastidious in their Nutritional Needs. Enriched Media is always a solid media. Ex. Blood Agar Chocolate Agar Egg Containing Media