Chlamydiae are obligate intracellular gram-negative bacteria Bacteria Bacteria are prokaryotic single-celled microorganisms that are metabolically active and divide by binary fission. Some of these organisms play a significant role in the pathogenesis of diseases. Bacteriology. They lack a peptidoglycan Peptidoglycan Penicillins layer and are best visualized using Giemsa stain Giemsa stain Borrelia. Chlamydiae species have a complex replication cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation consisting of 2 morphological forms: elementary bodies and reticulate bodies. The family of Chlamydiaceae comprises 3 pathogens that can infect humans: Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae. Sometimes, C. psittaci and C. pneumoniae are classified as a separate genus, Chlamydophila. C. trachomatis is the most common bacterium responsible for causing sexually transmitted diseases in the United States and is associated with urogenital infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease, lymphogranuloma venereum Lymphogranuloma venereum Subacute inflammation of the inguinal lymph glands caused by certain immunotypes of Chlamydia trachomatis. It is a sexually transmitted disease in the U.S. But is more widespread in developing countries. It is distinguished from granuloma venereum, which is caused by calymmatobacterium granulomatis. Chlamydial Infections, neonatal conjunctivitis Conjunctivitis Conjunctivitis is a common inflammation of the bulbar and/or palpebral conjunctiva. It can be classified into infectious (mostly viral) and noninfectious conjunctivitis, which includes allergic causes. Patients commonly present with red eyes, increased tearing, burning, foreign body sensation, and photophobia. Conjunctivitis, and trachoma Trachoma A chronic infection of the conjunctiva and cornea caused by Chlamydia trachomatis. Chlamydial Infections. C. psittaci causes psittacosis (parrot fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever), whereas C. pneumoniae causes atypical pneumonia Atypical pneumonia Mycoplasma.
Last updated: 13 Sep, 2021
Mnemonic
To help recall the characteristics of the life cycle Cycle The type of signal that ends the inspiratory phase delivered by the ventilator Invasive Mechanical Ventilation, remember the 3 Es and 2 Rs:
C. trachomatis: Perinuclear chlamydial inclusions (arrows) in a tissue culture of McCoy cells (a cell line originally derived from human synovial fluid) are seen on a Giemsa stain Giemsa stain Borrelia.
Image: “Perinuclear chlamydial inclusions (arrows) in McCoy cells when infected with the isolated strain” by Zhaocai Li, Xiaoan Cao, Baoquan Fu, Jizhang Zhou. License: CC BY 3.0Papanicolaou stain of a cervicovaginal cytology preparation showing three chlamydial intranuclear inclusions Intranuclear inclusions Circumscribed masses of foreign or metabolically inactive materials, within the cell nucleus. Some are viral inclusion bodies. Varicella-Zoster Virus/Chickenpox within squamous epithelial cells that are next to several normal epithelial cells
Image: “ Pap smear Pap smear Cytological preparation of cells collected from a mucosal surface and stained with Papanicolaou stain. Cervical Cancer Screening showing chlamydia in the vacuoles 500x H&E” by Dr. Lance Liotta Laboratory. License: Public DomainC. trachomatis | C. psittaci | C. pneumoniae | |
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Host range | Humans primarily |
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Humans only |
Transmission |
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Inhalation of contaminated, dried bird feces | Aerosolized droplets Droplets Varicella-Zoster Virus/Chickenpox |
Risk factors |
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Exposure Exposure ABCDE Assessment to birds | Crowded settings (schools, nursing homes); the elderly are at higher risk for severe disease. |
Growth
cycle
Cycle
The type of signal that ends the inspiratory phase delivered by the ventilator
Invasive Mechanical Ventilation of chlamydiae:
Elementary bodies (EB) are ingested into the cell after attaching to its surface and are then converted into the
reticulocyte
Reticulocyte
Immature erythrocytes. In humans, these are erythroid cells that have just undergone extrusion of their cell nucleus. They still contain some organelles that gradually decrease in number as the cells mature. Ribosomes are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic ‘reticulum’ (not the same as the endoplasmic reticulum), hence the name reticulocytes.
Erythrocytes: Histology body (RB) form. As RBs begin to replicate, they create a cluster known as an inclusion body. After replication terminates, the inclusion bodies
release
Release
Release of a virus from the host cell following virus assembly and maturation. Egress can occur by host cell lysis, exocytosis, or budding through the plasma membrane.
Virology EB forms, which leave the cell.
Pathogenesis of Chlamydia trachomatis
Image by Lecturio.Sexually transmitted:
Neonatal infections Infections Invasion of the host organism by microorganisms or their toxins or by parasites that can cause pathological conditions or diseases. Chronic Granulomatous Disease (serovars D–K):
Trachoma Trachoma A chronic infection of the conjunctiva and cornea caused by Chlamydia trachomatis. Chlamydial Infections (serovars A–C):
Trachoma
Trachoma
A chronic infection of the conjunctiva and cornea caused by Chlamydia trachomatis.
Chlamydial Infections
Recurrent episodes of infection with serovars A–C of Chlamydia trachomatis cause conjunctival
inflammation
Inflammation
Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body’s defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function.
Inflammation in children, who eventually develop
scarring
Scarring
Inflammation and
blindness
Blindness
The inability to see or the loss or absence of perception of visual stimuli. This condition may be the result of eye diseases; optic nerve diseases; optic chiasm diseases; or brain diseases affecting the visual pathways or occipital lobe.
Retinopathy of Prematurity as adults.
Lymphogranuloma venereum Lymphogranuloma venereum Subacute inflammation of the inguinal lymph glands caused by certain immunotypes of Chlamydia trachomatis. It is a sexually transmitted disease in the U.S. But is more widespread in developing countries. It is distinguished from granuloma venereum, which is caused by calymmatobacterium granulomatis. Chlamydial Infections caused by the invasive serovars L1, L2, or L3 of Chlamydia trachomatis. This young adult experienced an acute onset of tender, enlarged lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy in both groins.
Image: “Lymphogranuloma venerum – lymph nodes Lymph Nodes They are oval or bean shaped bodies (1 – 30 mm in diameter) located along the lymphatic system. Lymphatic Drainage System: Anatomy” by Herbert L. Fred, Hendrik A. van Dijk. License: CC BY 2.0Chlamydia trachomatis neonatal pneumonia Neonatal Pneumonia Pneumonia in Children: diffuse patchiness on a chest radiogram.
Image: “Chlamydial pneumonitis Pneumonitis Human Herpesvirus 6 and 7: a creepy neonatal disease Neonatal disease Diseases existing at birth and often before birth, or that develop during the first month of life, regardless of causation. of these diseases, those characterized by structural deformities are termed congenital abnormalities. Echovirus” by Hon KL, Leung AK AK Actinic keratosis (AK) is a precancerous skin lesion that affects sun-exposed areas. The condition presents as small, non-tender macules/papules with a characteristic sandpaper-like texture that can become erythematous scaly plaques. Actinic Keratosis. License: CC BY 3.0