Laboratory diagnosis of Legionella pneumophila 5/5 (6)

Laboratory diagnosis of Legionella pneumophila

Laboratory diagnosis of Legionella pneumophila Specimen: Respiratory secretions (sputum, bronchial aspirate or washings), as well as pleural fluid, lung biopsy or autopsy material. Microscopy Legionellae in clinical specimens stain poorly with Gram stain and the small, intracellular bacteria are rarely recognized. The organism will stain with nonspecific methods, such as Dieterle silver stain, but this […]

Laboratory diagnosis of Leprosy caused by Mycobacterium leprae 4.86/5 (7)

Laboratory diagnosis of Leprosy caused by Mycobacterium leprae

Laboratory diagnosis of Leprosy caused by Mycobacterium leprae Specimen Skin biopsies, nasal discharges, scrapings from the nasal mucosa and slit-skin smears which are prepared by making superficial incisions in the skin, scraping out some tissue fluid and cells. Skin smears The skin smears are collected from the leprous lesions, such as nodules, thick papules, and […]

Laboratory diagnosis, Treatment and Prevention of Mycoplasma pneumoniae 4.47/5 (19)

Laboratory diagnosis, Treatment and Prevention of Mycoplasma pneumoniae

Laboratory diagnosis of Mycoplasma pneumoniae Specimen Ideal specimens are throat swabs and nasopharyngeal aspirates, lung biopsies, expectorated sputum. Washings are more reliable than sputum specimens because most infected patients have a dry, nonproductive cough and do not produce sputum. Microscopy Test is not useful because organisms do not have a cell wall and do not […]

Laboratory diagnosis, Treatment and Prevention of Streptococcus pneumoniae 4.8/5 (10)

Laboratory diagnosis, Treatment and Prevention of Streptococcus pneumoniae

Laboratory diagnosis of Streptococcus pneumoniae Specimen: Sputum, blood, endotracheal aspirate, bronchoalveolar lavage, cerebrospinal fluid (CSF), pleural fluid, joint fluid, abscess fluid, bones, and other biopsy material. Microscopy Gram staining of sputum shows lancet shaped Gram-positive cocci in pairs. Fresh emulsified sputum mixed with antiserum causes capsule swelling (the quellung reaction) for identification of pneumococci. In […]

Virulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae 4.44/5 (9)

Virulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae

Virulence factors of Streptococcus pneumoniae Polysaccharide capsule The capsule is antiphagocytic, inhibiting complement deposition and phagocytosis. 2. Cell wall associated polymers and proteins Teichoic acid – binds to epithelial cells and activates alternative complement pathway Protein adhesion – binds to epithelial cells Peptidogylcan – activates alternative complement pathway Phosphorylcholine – mediates invasion of host cell […]

Laboratory diagnosis, treatment and prevention of Leptospira interrogans 4.45/5 (11)

Laboratory diagnosis, treatment and prevention of Leptospira interrogans

Laboratory diagnosis of Leptospira interrogans Specimens Specimens consist of aseptically collected blood in a heparin tube, CSF, urine, or tissues for microscopic examination and culture. Serum is collected for agglutination tests. Microscopy As leptospires are thin, they are at the limit of the resolving power of a light microscope and thus cannot be seen by […]

Pathogenesis and Clinical manifestations of Francisella tularensis 4.89/5 (9)

Pathogenesis and Clinical manifestations of Francisella tularensis

Pathogenesis of Francisella tularensis Francisella tularensis is carried by many species of wild rodents, rabbits, beavers. Humans become infected by handling the carcasses or skin of infected animals, by inhaling infective aerosols or ingesting contaminated water, through insect vectors and by being bitten by carnivores that have themselves eaten infected animals. Humans are infected by […]

Laboratory diagnosis, treatment and prevention of Borrelia burgdorferi 4.9/5 (10)

Laboratory diagnosis, treatment and prevention of Borrelia burgdorferi

Laboratory diagnosis of Borrelia burgdorferi Specimen Blood, cerebrospinal fluid, joint fluid, tissue biopsies Body fluids should be transported without any preservatives. Tissue biopsy specimens should be placed in sterile saline to prevent drying. Direct detection methods The organisms can be seen directly in wet preparations of peripheral blood (mixed with equal parts of sterile, non […]

Pathogenesis and Clinical manifestations of Rickettsia rickettsii 5/5 (3)

Pathogenesis and Clinical manifestations of Rickettsia rickettsii

Pathogenesis of Rickettsia rickettsii Human gets infected when infected adult tick inoculates Rickettsia rickettsii into the skin while taking a blood meal. It usually takes 6 hours of attachment and feeding before rickettsiae are transmitted to the host. Infection can also be transmitted occasionally by scratching and rubbing infectious tick feces into the abraded skin. After […]

Laboratory diagnosis, treatment and prevention of Rickettsia rickettsii 5/5 (4)

Laboratory diagnosis, treatment and prevention of Rickettsia rickettsii

Laboratory diagnosis of Rickettsia rickettsii Specimen: Skin biopsies, serum Direct detection method Although Rickettsiae stain poorly with Gram stain, they can be stained with Giemsa or Gimenez stains. Direct detection of R. rickettsii antigen in skin biopsy specimens of the rash from infected patients by direct fluorescent antibody test using the specific anti-rickettsial antibodies is a rapid […]

Pathogenesis and Clinical manifestations of Corynebacterium diphtheriae 4.88/5 (8)

Pathogenesis and Clinical manifestations of Corynebacterium diphtheriae

Pathogenesis of Corynebacterium diphtheriae In nature, C diphtheriae occurs in the respiratory tract, in wounds, or on the skin of infected persons or normal carriers. It is spread by droplets or by contact to susceptible individuals; the bacilli then grow on mucous membranes or in skin abrasions, and those that are toxigenic start producing toxin. […]

Laboratory diagnosis, treatment and prevention of Corynebacterium diphtheriae 4.83/5 (6)

Laboratory diagnosis, treatment and prevention of Corynebacterium diphtheriae

Laboratory diagnosis of Corynebacterium diphtheriae Specimen Dacron swabs from the nose, throat, or other suspected lesions must be obtained before antimicrobial drugs are administered. Swabs should be collected from beneath any visible membrane. The swab should then be placed in semisolid transport media such as Amies. Microscopy Smears stained with alkaline methylene blue or Gram stain […]

Virulence factors, Pathogenesis and Clinical manifestations of Listeria monocytogenes 4.55/5 (11)

Listeria monocytogenes

Virulence factors of Listeria monocytogenes 1. Adhesion proteins (Ami, Fbp A, flagellin) Mediate bacterial binding to host cell that contribute to virulence. 2. Listeriolysin O A hemolytic and cytotoxic toxin that allows for survival within phagocytes. 3. Internalin Cell surface protein that induces phagocytosis. 4. Act A Induces actin polymerization on the surface of host cells, […]

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