Chlamydiae Classification and Overview
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Questions and Answers

Which staining method allows for the better visualization of bacteria associated with the discussed microorganisms?

  • Methylene blue
  • Giemsa stain
  • Iodine stain (correct)
  • Crystal violet
  • What process do Elementary Bodies (EB) undergo to enter the host cells?

  • Endocytosis (correct)
  • Exocytosis
  • Diffusion
  • Osmosis
  • What characterizes the Reticulate Bodies (RB) compared to Elementary Bodies (EB)?

  • RB can be cultured in nutrient agar
  • RB are intracellular and metabolically active (correct)
  • RB are metabolically inert
  • RB are infectious and invasive
  • What is the significance of host cell rupture in the lifecycle of Reticulate Bodies?

    <p>To release daughter E Bodies for infection of other cells</p> Signup and view all the answers

    What distinguishes Elementary Bodies (EB) from Reticulate Bodies (RB)?

    <p>EB are extracellular, infectious and metabolically inert.</p> Signup and view all the answers

    What type of morphology do the discussed microorganisms exhibit?

    <p>Highly pleomorphic</p> Signup and view all the answers

    Which of the following species is NOT classified under the chlamydiae?

    <p>Chlamydia coli</p> Signup and view all the answers

    How do chlamydiae reproduce?

    <p>Via a replicative cycle followed by binary fission.</p> Signup and view all the answers

    Which characteristic is NOT associated with chlamydiae?

    <p>Capable of synthesizing ATP independently.</p> Signup and view all the answers

    What is the main risk factor associated with chlamydial infections?

    <p>They can produce heat labile toxins.</p> Signup and view all the answers

    What is the primary zoonotic disease associated with psittacine birds?

    <p>Psittacosis</p> Signup and view all the answers

    What is the drug of choice for treating psittacosis?

    <p>Tetracycline</p> Signup and view all the answers

    Which type of antibodies are commonly tested in serology for Chlamydia pneumoniae infection?

    <p>IgG and IgM</p> Signup and view all the answers

    What is a key characteristic of Chlamydia pneumoniae infections?

    <p>High prevalence of asymptomatic cases</p> Signup and view all the answers

    Which method is utilized for diagnosing psittacosis in the laboratory?

    <p>Fluorescent monoclonal antibody staining</p> Signup and view all the answers

    Which serotypes of Chlamydia trachomatis are responsible for causing Trachoma?

    <p>A, B, C</p> Signup and view all the answers

    What is the primary mode of transmission for Trachoma?

    <p>Direct and indirect contact</p> Signup and view all the answers

    Which type of infections is associated with Chlamydia trachomatis serotypes D-K?

    <p>Getnal infections</p> Signup and view all the answers

    Which condition can result from scarring and inversion of the eyelids due to Trachoma?

    <p>Entropion</p> Signup and view all the answers

    What is a common symptom of Trachoma in its early stages?

    <p>Mucopurulent discharge</p> Signup and view all the answers

    How long is the typical incubation period for Inclusion conjunctivitis?

    <p>2-5 days</p> Signup and view all the answers

    Which organism is resistant to sulfonamide treatment?

    <p>Psittacosis</p> Signup and view all the answers

    What is a serious consequence of untreated Trachoma?

    <p>Preventable blindness</p> Signup and view all the answers

    What percentage of infected women are asymptomatic in genital C.trachomatis infections?

    <p>75%</p> Signup and view all the answers

    Which of the following is NOT a complication associated with chlamydial infections?

    <p>Pre-eclampsia</p> Signup and view all the answers

    What is the most common method for laboratory diagnosis of genital C.trachomatis infections?

    <p>Urine tests</p> Signup and view all the answers

    What is the primary stage of Lymphogranuloma Venereum (LGV) characterized by?

    <p>Painless vesiculo-papular ulceration</p> Signup and view all the answers

    Which of the following treatments is commonly used for genital chlamydial infections?

    <p>Azithromycin</p> Signup and view all the answers

    What is the incubation period for Lymphogranuloma Venereum (LGV) after exposure?

    <p>3 days to 1 month</p> Signup and view all the answers

    Which of these is a mode of transmission for genital C.trachomatis infection?

    <p>Anal sex</p> Signup and view all the answers

    Which technique is utilized to culture C.trachomatis in a laboratory setting?

    <p>McCoy cells</p> Signup and view all the answers

    Study Notes

    Chlamydiae Classification

    • Chlamydia are obligate intracellular pathogens
    • They are classified as:
      • Phylum: Chlamydiae
      • Class: Chlamydiae
      • Order: Chlamydiales
      • Family: Chlamydiaceae
      • Genus: Chlamydia
      • Species: C. trachomatis, C. psittaci, C. pneumoniae

    Chlamydia Overview

    • Chlamydia are small, round to oval bacteria
    • They were initially thought to be large viruses
    • They possess a cell wall lacking peptidoglycan, similar to Gram-negative bacteria.
    • They contain both RNA and DNA.
    • They are susceptible to some antibacterial agents such as tetracyclines and erythromycin.
    • Chlamydia lack the necessary energy machinery for independent existence.
    • They cannot synthesize ATP or oxidize NADH.
    • They reproduce through a replicative cycle, followed by binary fission.
    • They are highly infectious and many species produce heat-labile toxins.

    Chlamydia Morphology and Life Cycle

    • Chlamydia exist in two forms:
      • Elementary bodies (EB): Extracellular, infectious, invasive stage, metabolically inert. They enter the body through endocytosis, a process similar to phagocytosis.
      • Reticulate bodies (RB) or initial bodies (IB): Intracellular, non-infectious, metabolically active. When EB undergo a transformation, they reorganize into RB which are less dense. They obtain energy (ATP) from the host cell and this transformation takes approximately 24-72 hours. RB undergo binary fission within the host cell's intracytoplasmic vacuole/phagosome. Host cell rupture releases daughter EB, allowing the infection to spread.

    Chlamydia Species

    • The three main species of Chlamydia can be distinguished by several parameters:
      • C. psittaci: Contains glycogen in intracytoplasmic inclusion body, sensitive to sulfonamide. Causes psittacosis in birds and humans.
      • C. trachomatis: Lack glycogen in intracytoplasmic inclusion body, resistant to sulfonamide. Causes trachoma, inclusion conjunctivitis, and various genital infections.
      • C. pneumoniae: Lack glycogen in intracytoplasmic inclusion body, resistant to sulfonamide. Causes atypical pneumonia, bronchitis, and sinusitis.

    Chlamydia trachomatis Infections

    • Ocular Infections:

      • Trachoma: Caused by serotypes A, B, and C. It is a chronic keratoconjunctivitis that is a leading cause of preventable blindness globally. Transmission occurs through direct contact, indirect contact via fomites, and during childbirth.
      • Inclusion Conjunctivitis: Caused by serotypes D-K. It is an acute suppurative disease of the conjunctiva. Occurs in infants and adults and has an incubation period of 2-5 days. Transmission is by direct or indirect contact.
    • Genital Infections: Caused by serotypes D-K. It is a common cause of sexually transmitted infections (STIs) worldwide.

      • Non-gonococcal urethritis (NGU) is common, particularly among young adults.
      • Other genital infections include cervicitis, epididymitis, salpingitis, endometritis, pelvic inflammatory disease (PID), proctitis, pharyngitis, and Reiter's syndrome.
      • Chlamydial infections can lead to infertility and sterility.

    Chlamydia psittaci Infections

    • Pathogen: Primarily infects birds, particularly psittacine birds (e.g., parrots), and other avian species.
    • Transmission: Humans get infected by inhaling bacteria from infected bird droppings.
    • Disease: It causes psittacosis (ornithosis) in humans, a zoonotic disease of the lower respiratory tract. Symptoms range from mild to severe pneumonia and meningo-pneumonitis.

    Chlamydia pneumoniae Infections

    • Prevalence: Highly common worldwide, with 30-50% of the population having antibodies to C. pneumoniae.
    • Transmission: Spread through airborne transmission. No known animal reservoir.
    • Disease: Most infections are asymptomatic. It can cause upper and lower respiratory tract infections (URTI and LRTI), including atypical pneumonia, bronchitis, sinusitis, and pharyngitis. It can also exacerbate asthma.

    Chlamydia Diagnosis

    • Clinical diagnosis: Based on patient history and clinical symptoms.
    • Laboratory diagnosis:
      • Specimens: Post-voidal urine, urethral swab, endometrial scraping, culdocentesis, conjunctival scraping, posterior nasopharyngeal swab, tracheal/bronchial aspirates.
      • Methods:
        • Urine tests: Detect C. trachomatis genes, results in 24 hours.
        • Culture: In McCoy cells,takes 3 days or more. Requires expertise and experience.
        • DFA test: Direct fluorescent antibody test.
        • Enzyme immunoassay:

    Chlamydia Treatment and Prevention

    • Treatment: Early detection and treatment are crucial.
      • Antibiotics: Tetracycline, doxycycline, minocycline, erythromycin, and azithromycin.
    • Complications: HIV/AIDS, PID, subfertility, infertility.
    • Prevention and Control:
      • Prophylactic treatment: Use of prophylactic ophthalmic eye drops for newborns, oral tetracycline or sulfonamides.
      • Hygiene: Personal and family hygiene.
      • Trachoma clinics: Establishment of dedicated clinics in endemic areas.

    Lymphogranuloma Venereum (LGV)

    • Caused by: Unique serovars of Chlamydia trachomatis (L1, L2, L3). These serovars differ from those causing urethritis, cervicitis, and proctitis (D-K).
    • Presentation: Varies depending on the site of infection.
    • Incubation period: 3 days to 1 month after exposure.
    • Progression: It is an invasive, systemic infection that progresses in three stages:
      • Primary (Ulcer) stage: Painless vesiculo-papular ulceration at the site of inoculation, resembling a herpes lesion. Ulcer heals on its own in a few days.
      • Secondary stage: Developing weeks to months later, symptoms include inguinal lymphadenopathy, buboes, and fever. Buboes can become fluctuant and drain.
      • Tertiary stage: May occur months to years later, characterized by inflammatory strictures in the rectum, urethra, or vagina.

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    Description

    Dive into the fascinating world of Chlamydia with this quiz. Learn about their classification, morphological characteristics, and unique life cycle. Understand their role as obligate intracellular pathogens and their significance in infectious diseases.

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