Chlamydiae Classification and Morphology

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Questions and Answers

What type of cell division do Reticulate Bodies (RB) undergo within host cells?

Binary fission (correct)

Mitosis

Meiosis

Budding

How are Elementary Bodies (EB) characterized in terms of their metabolic activity?

Metabolically active and invasive

Metabolically inert and non-invasive

Metabolically inert and infectious (correct)

Metabolically active and non-infectious

What is the preferred staining technique for better visualization of the structure mentioned?

Gram staining

Acid-fast staining

Iodine staining (correct)

Giemsa staining

What role does the host cell play in the process involving Reticulate Bodies (RB)?

Supplying energy/ATP Signup and view all the answers

What is the morphology of the cells discussed in the content?

Highly pleomorphic Signup and view all the answers

Which of the following correctly classifies the species of Chlamydia?

Chlamydia trachomatis, Chlamydia psittaci, Chlamydia pneumoniae Signup and view all the answers

What is a characteristic feature of Chlamydia species?

They possess a rigid cell wall lacking peptidoglycan. Signup and view all the answers

What is the function of Elementary Bodies (EB) in the life cycle of Chlamydia?

They are the invasive and infectious stage entering the host. Signup and view all the answers

Chlamydia's inability to synthesize ATP means that it relies on what for energy?

The host cell's energy resources. Signup and view all the answers

Which statement about Chlamydia's reproduction is accurate?

They undergo a binary fission process after an initial replicative cycle. Signup and view all the answers

What is the primary mode of transmission for psittacosis to humans?

Inhalation of bacteria from droppings Signup and view all the answers

What is the recommended drug of choice for treating psittacosis?

Tetracycline Signup and view all the answers

Which laboratory method is commonly used to diagnose infections caused by C. pneumoniae?

Fluorescent antibody tests Signup and view all the answers

What type of symptoms can psittacosis cause in humans?

Meningo-pneumonitis and pneumonia Signup and view all the answers

Which of the following statements about C. pneumoniae is incorrect?

It requires a high temperature to grow in culture. Signup and view all the answers

What percentage of infected women with genital C.trachomatis infection are typically asymptomatic?

75% Signup and view all the answers

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

Endometrial hyperplasia Signup and view all the answers

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

Painless vesiculo-papular ulceration Signup and view all the answers

Which specimen is NOT typically used for the laboratory diagnosis of genital chlamydial infection?

Blood sample Signup and view all the answers

Which treatment is NOT recommended for genital C.trachomatis infections?

Amoxicillin Signup and view all the answers

What is a common method for the diagnosis of chlamydial infections that can provide test results in 24 hours?

Urine tests Signup and view all the answers

Lymphogranuloma Venereum (LGV) is caused by which serovars of Chlamydia trachomatis?

L1, L2, L3 Signup and view all the answers

Which of the following is a preventative measure for chlamydial infections in newborns?

Antibiotic prophylaxis Signup and view all the answers

Which serotypes of Chlamydia trachomatis are responsible for causing trachoma?

Serotypes A, B, C Signup and view all the answers

What is a common clinical feature of trachoma?

Mucopurulent eye discharge Signup and view all the answers

What is the primary mode of transmission for trachoma?

Direct contact and fomites Signup and view all the answers

Which of the following diseases is caused by Chlamydia pneumoniae?

Atypical pneumonia Signup and view all the answers

What type of infections are associated with serotypes D-K of Chlamydia trachomatis?

Both ocular and genital infections Signup and view all the answers

Which condition represents chronic kerato-conjunctivitis caused by Chlamydia trachomatis?

Trachoma Signup and view all the answers

What is the approximate incubation period for trachoma?

3-10 days Signup and view all the answers

Which serotypes of Chlamydia trachomatis are linked with Lymphogranuloma venereum (LGV)?

Serotypes L1, L2, L3 Signup and view all the answers

Study Notes

Classification

Chlamydiae are a phylum of bacteria, containing the class Chlamydiae, order Chlamydiale, family Chlamydiacae, and genus Chlamydia.
Chlamydia includes the species: C. trachomatis, C. psittaci, and C. pneumoniae.

Introduction

Chlamydiae are obligate intracellular pathogens, meaning they can only survive and reproduce inside living cells.
They are small, round to oval cells, once believed to be large viruses.
They have a rigid cell wall lacking peptidoglycan, similar to Gram-negative bacteria.
They contain DNA and RNA.
They are susceptible to some antibacterial agents, such as tetracyclines and erythromycin.
They lack energy machinery for independent existence: they cannot synthesize ATP or oxidize NADH.
They reproduce through a replicative cycle followed by binary fission.
Most species produce heat-labile toxins.

Morphology

Chlamydiae are highly pleomorphic, meaning they can have different shapes and sizes.
They are small, round to oval cells.
They can be visualized using electron microscopy with Giemsa stain, but are best visualized with iodine stain, appearing brown in color.
They are identified by their characteristic inclusion bodies within the host cell.
They can be cultured in the laboratory in the yolk sac of chicken eggs.

Chlamydia trachomatis Infections

Ocular infections:
- Trachoma: caused by serotypes A, B, and C, leading to chronic keratoconjunctivitis, a common cause of preventable blindness worldwide.
- Inclusion conjunctivitis: caused by serotypes D-K, resulting in an acute, suppurative disease of the conjunctiva.
Genital infections:
- Caused by serotypes D-K, leading to Non-Gonococcal Urethritis (NGU), cervicitis, epididymitis, salpingitis, endometritis, pelvic inflammatory disease (PID), proctitis, pharyngitis, Reiter's syndrome, subfertility, and infertility.
LGV (Lymphogranuloma Venereum): caused by serotypes L1-L3, resulting in an invasive, systemic infection that progresses in three stages.

Chlamydia psittaci

Naturally infects birds, particularly psittacine birds like parrots and pigeons.
Transmission to humans occurs through inhalation of bacteria from bird droppings.
Causes a zoonotic disease of the lower respiratory tract called psittacosis (ornithosis), ranging from subclinical to lethal pneumonia and meningo-pneumonitis.
It is an occupational disease for those handling poultry.

Chlamydia pneumoniae

Very common worldwide, with 30-50% of people having antibodies to C. pneumoniae.
Airborne transmission.
Most infections are asymptomatic.
Causes various respiratory infections, including atypical pneumonia, bronchitis, sinusitis, pharyngitis, and exacerbations of asthma.

Diagnosis

Clinical diagnosis based on patient history and symptoms.
Laboratory diagnosis involves collecting specimens like urine, swabs, aspirates, and scrapings.
Urine tests are available within 24 hours.
Culture in McCoy cells takes 3 days or more.
Tests include DFA (Direct Fluorescent Antibody) and Enzyme Immunoassay.

Treatment

Early detection and treatment are essential.
Medications include tetracycline, doxycycline, minocycline, erythromycin, and azithromycin.

Prevention and Control

Routine prophylactic eye drops for newborns.
Oral tetracycline or sulfonamides.
Personal and family hygiene.
Population surveys and establishment of trachoma clinics.

Complications

Complications include HIV/AIDS, PID, subfertility, and infertility.

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Description

Explore the unique characteristics of Chlamydiae, a phylum of bacteria that are obligate intracellular pathogens. This quiz covers their classification, morphology, and reproductive processes. Test your knowledge on the distinct features that differentiate Chlamydiae from other bacteria.