Toxin produced by bacterial growth diffuses in agar medium and produces line of precipitation where it meets antitoxin molecules (dispersed from the filter paper) in optimum concentration (Fig. Usually the result can be read within 48 hours, sometimes precipitin lines may take up to 72 hours to develop. This technique is not only very convenient but also economical. The lines of precipitate radiate from the intersection of the strip and the bacterial growth. Tissue culture test: This is done by incorporation of test bacteria into an agar overlay of cell culture monolayers The toxin produced diffuses into the underlying cells causing death of the cells. The important distinguishing features of, c diphtheriae, table.1.
(a) Subcutaneous test: overnight growth of loefflers slope is first mixed with 2 to 5 disease ml nutrient broth and.3 ml from this emulsified growth is injected subcutaneously in thigh in two guinea pigs, one of which has received an intramuscular injection of 500 units. The unprotected animal will die within 2 to 3 days. At autopsy, other important pijn findings include: gelatinous, haemorrhagic oedema and often with necrosis at the site of injection; draining lymph nodes-swollen; clear, cloudy or blood-stained pleural and peritoneal fluid; and abdominal viscera-congested. The adrenal gland finding (haemorrhage) is pathognomonic feature. This method is not usually followed because of wastage of animals. (b) Intra-cutaneous test: Two guinea pigs or rabbits are injected intracutaneously with.2 ml emulsion from growth in loefflers serum medium, one of which is protected with 500 units of antitoxin the previous day (control animal) and to the other animal 50 units of diphtheria. The unprotected animal develops local erythematous lesion at the site of injection in 48-72 hours but there is no change in the control animal. By intra-cutaneous method, 8 to 10 cultures can be tested on a pair of animals and the animals do not die. In vitro test (Eleks Agar-gel precipitation test This in vitro immune-diffusion test, described by Elek (1949 provides a rapid and economic alternative to in vivo test. A rectangular strip of filter paper soaked in antitoxin (1,000 units/ml) is placed on the surface of a serum agar plate containing 20 horse serum while the medium is still in fluid form. When the medium solidifies, the testing strain is streaked across the plate at right angles to the filter paper strip and then incubated at 37C for 24 to 48 hours.
Category: Bacterial diseases - wikipedia
The microscopic morphology is best seen on loefflers medium. Smear from culture stained with Albert stain show typical bacilli. (b) Tellurite blood agar medium and ordinary blood agar medium: It is incubated for 36-48 hours. Studies on colonies on tellurite medium is helpful in distinguishing the biotypes. The colonies show characteristic gray-to-black colour on tellurite agar. Virulence test : advertisements: All isolates. Diphtheriae should be tested for virulence for toxigenicity which can be done either in vivo (animal inoculation) tadalafil or in vitro (Eleks test). Animal inoculation test: guinea pigs and rabbits are susceptible but rat and mice are resistant to the action of toxin.
Pathogenic bacteria - wikipedia
Penicillin is therefore useless as a therapeutic agent. Most cases are accompanied by a mild pneumonia, and erythromycin is generally recommended for therapy. The disease is sometimes called primary atypical pneumonia and is often described as walking pneumonia. Legionnaires' disease, or legionellosis, was first recognized in 1976 when an outbreak occurred among American Legion members attending a convention in Philadelphia. The causative agent is a gram-negative rod called Legionella pneumophila. The organism exists where water collects and is airborne in wind gusts. Cases of Legionnaires' disease are accompanied by high fever, lung consolidation, and pneumonia.
This condition is called miliary tuberculosis. Sometimes the disease is called consumption. Tuberculosis may be treated over a period of months with several drugs, including isoniazid (inh rifampin, streptomycin, pyrazinamide, ethambutol, and others. The tuberculin skin test is based on a type of cellular (delayed) hypersensitivity and is used to determine whether a person has had a previous exposure to tuberculosis antigens. One variation, the mantoux test, uses dilutions of antigen called ppd (purified protein derivative which are injected superficially to the skin to induce a reaction. A vaccine called bcg (bacille calmette guerin ) is prepared from bovine tubercle bacilli and is available for immunization. Pneumococcal pneumonia is caused by Streptococcus pneumoniae, the pneumococcus.
This organism is a gram-positive goedaardig pair of cocci occurring in chains. There are almost 100 serological types of the organism, and the vaccine currently available provides protection against approximately 25 of them. The disease involves the lung tissues and is accompanied by fever, consolidation of the lung (filling of the air spaces with bacteria, fluid, and debris and severe chest pains, with blood in the sputum. Aggressive penicillin therapy is used in treatment. Many individuals are healthy carriers of the bacterium. Mycoplasmal pneumonia is caused by mycoplasma pneumoniae, a species of mycoplasma. Mycoplasmas are exceptionally small, submicroscopic bacteria (about.15 μm) that have no cell walls.
Ncird about, division of Bacterial
Streptococcus pneumoniae, haemophilus influenzae, and, staphylococcus aureus. Antibiotic therapy is usually indicated. Pertussis is caused by the Gram-negative bacterium. Transmitted by airborne droplets, this organism multiplies in the trachea and bronchi and causes paroxysms of cough. A rapid inrush of air following a paroxysm results in the high-pitched whooping sound. Treatment is rendered with erythromycin and other antibiotics, and immunization may be performed with killed pertussis bacilli in the.
Dpt vaccine or acellular bacterial fragments in the. Tuberculosis is caused by, mycobacterium tuberculosis, an acid-fast rod. The bacteria have large amounts of mycolic acid in their cell walls, which permits them to retain carbolfuchsin stain despite a washing with acid-alcohol. The bacteria are acquired in respiratory droplets and infect the lung tissues. Tuberculosis is accompanied by the formation of tubercles, which are nodules on the lung tissue. The tubercle has a soft, cheeselike center and is surrounded by layers of macrophages and T-lymphocytes. When the lesions heal as calcified bodies, they are called. In some individuals, the tubercles continue to grow, and the lesion may rupture to release microorganisms into the bloodstream for spread to other body organs.
List of Bacterial Diseases, infections
Diphtheria is caused by vatting a club-shaped, Gram-positive rod called. The disease is characterized by sore throat, neck swelling, and blockage of the respiratory passageways with membranelike accumulations. These accumulations are due to the effects of a bacterial exotoxin, which destroys cells of the epithelial lining. Antibiotic therapy is augmented by administration of antitoxins to neutralize the toxins. Immunization is imparted in the. Dpt vaccine, in which diphtheria toxoid is employed. Otitis media is infection of the middle ear accompanied by earache. Numerous bacteria may cause this problem including.
Bacterial vaginosis - symptoms and
Diagnosis can be performed by obtaining throat swabs and combining the bacteria present with specific antibodies coated to beads. If the beads clump together, then. Pyogenes is presumably present. Cases of strep throat are treated with penicillin antibiotics. Scarlet fever onder is caused by, streptococcus pyogenes, the same organism that causes strep throat. In scarlet fever, the betahemolytic streptococci produce an erythrogenic toxin, which causes a skin rash. The fever is usually high, the throat tissues are inflamed, and the tongue exhibits a strawberrylike appearance (strawberry tongue). Penicillin antibiotics are normally used in therapy.
Microbial diseases of the respiratory system may occur in the upper or lower regions. The upper region consists of the nose, pharynx, and other structures such as the middle ear and sinuses. Although many defensive mechanisms exist in this part of the body, such as ciliated hairs and mucous membranes, infections are common because of the proximity to the external environment. The lower portion of the system consists of the respiratory tubes and alveoli of the lungs. Infection occurs here because of the excessive moisture and rich supply of nutrients. The common strep throat is due to a group A betahemolytic classes streptococcus known. This Gram-positive organism is encapsulated and produces streptokinase, which breaks down fibrin clots and permits the organism to spread to other tissues. The disease is accompanied by enlarged lymph nodes, inflamed tissues, and pus found on the tonsils.
Bacterial Diseases, of Tomato
Two swabs are taken from the site of lesion (throat, nose or larynx one for smear examination and other for culture. Direct smear examination: advertisements: Smears stained by Alberts stain show beaded slender rods in typical Chinese-letter pattern. The results of microscopic examination of clinical material may not always be reliable. Interpretation of the smear requires technical expertise. Hence smear examination alone is not sufficient for the diagnosis. Specimen should always be cultured. Culture: Swab is inoculated on the following culture media: (a) loefflers serum slope: Growth appears in 6-8 hours but, if negative, the media problematiek will have to be incubated for 24 hours.
These are also called diphtheroids. Bacteriological Studies : For control measures and epidemiological studies laboratory confirmation of diphtheria is necessary. Specific treatment against diphtheria (antitoxin and antibiotic) should be given immediately after clinical diagnosis without waiting for laboratory findings.