Pathogenesis and Clinical Manifestations of Leptospira interrogans

Pathogenesis and Clinical Manifestations of Leptospira interrogans

Pathogenesis of Leptospira interrogans Leptospires usually enter the body through the mucous membranes of the upper respiratory tract or the conjunctivae, or through abraded skin, following exposure to contaminated water, infected urine or animal tissues. Ingestion is considered to be less important. The severity of the leptospirosis depends on (a) host immunity, (b) virulence of … Read morePathogenesis and Clinical Manifestations of Leptospira interrogans

Sandwich ELISA- Steps and Advantages

Sandwich ELISA- Steps and Advantages

The sandwich ELISA quantify antigens between two layers of antibodies (i.e. capture and detection antibody). Sandwich ELISA is named so as antigen is sandwiched between two antibodies. The sandwich assay uses two different antibodies that are reactive with different epitopes on the antigen with a concentration that needs to be determined. The antigen to be … Read moreSandwich ELISA- Steps and Advantages

Pathogenesis and Clinical Manifestations of Borrelia burgdorferi

Pathogenesis and Clinical Manifestations of Borrelia burgdorferi

Pathogenesis of Lyme disease caused by Borrelia burgdorferi Lyme disease is caused by the spirochete B. burgdorferi, which is transmitted by the bite of a small tick of the genus Ixodes. Humans are “accidental” hosts for B. burgdorferi because spirochetes from infected people are not transmitted to other hosts. While in the midgut of the Ixodes tick … Read morePathogenesis and Clinical Manifestations of Borrelia burgdorferi

Laboratory Diagnosis, Treatment and Prevention of Francisella tularensis

Laboratory diagnosis of Francisella tularensis

Laboratory diagnosis of Francisella tularensis Specimen Scrapings from infected ulcers, lymph node biopsies, and sputum, whole blood. Serum is generally collected from all patients early in disease and during convalescence. To minimize the loss of viable organisms, samples should be transported to the laboratory within 24 hours. If specimens are to be held longer than … Read moreLaboratory Diagnosis, Treatment and Prevention of Francisella tularensis

Laboratory diagnosis of Legionella pneumophila

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 … Read moreLaboratory diagnosis of Legionella pneumophila

Laboratory diagnosis of Leprosy caused by Mycobacterium leprae

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 … Read moreLaboratory diagnosis of Leprosy caused by Mycobacterium leprae

B Cells (B-Lymphocytes)

B Cells (B-Lymphocytes)

B lymphocytes, the cells that produce antibodies, were so called because in birds they were found to mature in an organ called the Bursa of Fabricius. In mammals, no anatomic equivalent of the bursa exists, and the early stages of B cell maturation occur in the bone marrow. Thus, B lymphocytes now refer to bone … Read moreB Cells (B-Lymphocytes)

Laboratory diagnosis, Treatment and Prevention of Mycoplasma pneumoniae

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 … Read moreLaboratory diagnosis, Treatment and Prevention of Mycoplasma pneumoniae

Laboratory diagnosis, Treatment and Prevention of Streptococcus pneumoniae

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 … Read moreLaboratory diagnosis, Treatment and Prevention of Streptococcus pneumoniae

Virulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae

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 … Read moreVirulence factors, Pathogenesis and Clinical manifestations of Streptococcus pneumoniae