This document provides information on the genus Chlamydia, including C. trachomatis, C. psittaci, and C. pneumoniae. It describes their morphology, life cycles, diseases caused, epidemiology, pathogenesis, diagnosis, treatment and prevention. Chlamydia are obligate intracellular parasites that cause respiratory infections like pneumonia as well as sexually transmitted diseases. Diagnosis involves culture, antigen detection, serology and nucleic acid tests. Treatment is with tetracycline or erythromycin. Prevention focuses on treatment, vaccination, and improving sanitation.

1. ChlamydiaChlamydia
Shilpa.KShilpa.K
Microbiology TutorMicrobiology Tutor
AIMSRCAIMSRC

2. Family:Family: ChlamydiaceaeChlamydiaceae
Genus:Genus: ChlamydiaChlamydia
– C. trachomatisC. trachomatis
Urogenital infections, Trachoma,Urogenital infections, Trachoma,
Conjunctivitis, Pneumonia,Conjunctivitis, Pneumonia,
Lymphogranuloma venerium (LGV)Lymphogranuloma venerium (LGV)
– C. psittaciC. psittaci
Pneumonia (Psittacosis)Pneumonia (Psittacosis)
– C. pneumoniaeC. pneumoniae
Bronchitis, sinusitis,Bronchitis, sinusitis,
PneumoniaPneumonia
?? AtherosclerosisAtherosclerosis

3. Chlamydia-Chlamydia- MicrobiologyMicrobiology
Small obligate intracellular parasitesSmall obligate intracellular parasites
Contain DNA, RNA and ribosomesContain DNA, RNA and ribosomes
Gram Negative cell wallGram Negative cell wall
– Cell wall not well characterizedCell wall not well characterized
– Inner and outer membraneInner and outer membrane
– LPS but no peptidoglycanLPS but no peptidoglycan
Dependant on energy moleculesDependant on energy molecules
– Can’t make ATPCan’t make ATP

4. Physiology and StructurePhysiology and Structure
Two morphological formsTwo morphological forms
– Elementary bodyElementary body
– Reticulate bodyReticulate body
Elementary bodies (EB)Elementary bodies (EB)
– Small (0.3 - 0.4 µm),Small (0.3 - 0.4 µm), ExtracellularExtracellular
– Rigid outer membrane, ResistantRigid outer membrane, Resistant
– Non-replicating, non-metabolically activeNon-replicating, non-metabolically active
– InfectiousInfectious
Bind to columnar epithelial cells / MacrophagesBind to columnar epithelial cells / Macrophages

5. Physiology and StructurePhysiology and Structure
Reticulate bodies (RB)Reticulate bodies (RB)
– Larger (0.8 - 1 µm)Larger (0.8 - 1 µm)
– IntracellularIntracellular
– Fragile membraneFragile membrane
– Metabolically activeMetabolically active
– ReplicatingReplicating
– Non-infectiousNon-infectious

6. Developmental Cycle ofDevelopmental Cycle of
ChlamydiaChlamydia
EB bind to host cellsEB bind to host cells
– Epithelial cellEpithelial cell
– MacrophageMacrophage
InternalizationInternalization
– EndocytosisEndocytosis
– PhagocytosisPhagocytosis
Inhibition of phagosome-Inhibition of phagosome-
lysosome fusionlysosome fusion
Reorganization into RBReorganization into RB
Growth of RB by binaryGrowth of RB by binary
fissionfission

7. Developmental Cycle ofDevelopmental Cycle of
ChlamydiaChlamydia
Reorganization into EBReorganization into EB
Inclusion bodiesInclusion bodies
Release of EBRelease of EB
– LysisLysis --C. psittaciC. psittaci
– ExtrusionExtrusion -- C. trachomaC. trachoma
andand C. pneumoniaeC. pneumoniae

8. Chlamydia trachomatisChlamydia trachomatis
TrachomaTrachoma
Inclusion conjunctivitisInclusion conjunctivitis
Pneumonia in infantsPneumonia in infants
Urogenital infectionsUrogenital infections
Reiter’s SyndromeReiter’s Syndrome
Lymphogranuloma venerium (Lymphogranuloma venerium (LGVLGV))

9. C. trachomatisC. trachomatis
BiovarsBiovars - biological variants- biological variants
– TrachomaTrachoma
– LGVLGV
SerovarsSerovars - serological variants- serological variants
– Major outer membrane proteinsMajor outer membrane proteins
– A through LA through L

10. C.C. trachomatis - Serovarstrachomatis - Serovars
TRIC agents

11. Pathogenesis andPathogenesis and
Immunity (Immunity (C.trachomatis)C.trachomatis)
Infects epithelial cells / MacrophagesInfects epithelial cells / Macrophages
Down regulation of Class I MHCDown regulation of Class I MHC
Infiltration of PMNs and lymphocytesInfiltration of PMNs and lymphocytes
Lymphoid follicle formationLymphoid follicle formation
FibrosisFibrosis
Disease results from destruction of cellsDisease results from destruction of cells
and host immune responseand host immune response
No long lasting immunity; reinfectionNo long lasting immunity; reinfection
results in inflammatory responseresults in inflammatory response

12. C. trachomatisC. trachomatis - Epidemiology- Epidemiology
TrachomaTrachoma
– WorldwideWorldwide
– Poverty and overcrowdingPoverty and overcrowding
– Endemic in Africa, Middle East, India, SE AsiaEndemic in Africa, Middle East, India, SE Asia
– Infection of childrenInfection of children
– TransmissionTransmission: droplets, hands, contaminated: droplets, hands, contaminated
clothing, flies, contaminated birth canalclothing, flies, contaminated birth canal

13. C. trachomatisC. trachomatis - Epidemiology- Epidemiology
Genital tract infectionsGenital tract infections
– Biovar: TrachomaBiovar: Trachoma
STDSTD
50 million new cases/year worldwide50 million new cases/year worldwide
– Biovar: LGVBiovar: LGV
Prevalent in Africa, Asia and South AmericaPrevalent in Africa, Asia and South America

14. TrachomaTrachoma
Chronic or repeated infectionChronic or repeated infection
– Follicle formation on conjunctivaFollicle formation on conjunctiva
– Scarring of the conjunctivaScarring of the conjunctiva

15. TrachomaTrachoma
Eyelids turn in and abrade corneaEyelids turn in and abrade cornea
– UlcerationUlceration
– ScarringScarring
– Blood vessel formationBlood vessel formation

16. TrachomaTrachoma
Flow of tears impededFlow of tears impeded
– Secondary infectionsSecondary infections

17. TrachomaTrachoma

19. Inclusion ConjunctivitisInclusion Conjunctivitis ((C.trachomatisC.trachomatis))
Associated with genital chlamydiaAssociated with genital chlamydia
Mucopurulent dischargeMucopurulent discharge
Corneal infiltrates, vascularization andCorneal infiltrates, vascularization and
scarring can occurscarring can occur
In neonates infection results fromIn neonates infection results from
infected birth canalinfected birth canal
– Apparent 5-12 days after birthApparent 5-12 days after birth
– Ear infection and rhinitis often accompanyEar infection and rhinitis often accompany
ocular diseaseocular disease

20. Infant PneumoniaInfant Pneumonia
((C.trachomatisC.trachomatis biovar: trachoma)biovar: trachoma)
Associated with genital chlamydiaAssociated with genital chlamydia
Infection arises from contaminated birthInfection arises from contaminated birth
canalcanal
Wheezing cough and pneumonia but noWheezing cough and pneumonia but no
feverfever
Often preceded by conjunctivitisOften preceded by conjunctivitis

21. Urogenital InfectionsUrogenital Infections
((C.trachomatisC.trachomatis))
FemalesFemales
– Asymptomatic (80%)Asymptomatic (80%)
– Cervicits, urethritis and salpingitisCervicits, urethritis and salpingitis
– Postpartum feverPostpartum fever
– Increased rateIncreased rate
Premature deliveryPremature delivery
Ectopic pregnancyEctopic pregnancy

22. Urogenital InfectionsUrogenital Infections
((C.trachomatisC.trachomatis))
MalesMales
– Symptomatic (75%)Symptomatic (75%)
– Urethritis, dysuria and pyuriaUrethritis, dysuria and pyuria
– Cause ofCause of nongonococcal urethritisnongonococcal urethritis (35 - 50%)(35 - 50%)
– Common cause ofCommon cause of postgonococcal urethritispostgonococcal urethritis

23. Reiter’s SyndromeReiter’s Syndrome
Conjunctivitis, polyarthritis and genital orConjunctivitis, polyarthritis and genital or
gastrointestinal inflammationgastrointestinal inflammation
Associated with HLA-B27Associated with HLA-B27
50 - 65 % have50 - 65 % have C. trachomatisC. trachomatis infectioninfection
80% have antibodies to80% have antibodies to C. trachomatisC. trachomatis

24. Lymphogranuloma VenereumLymphogranuloma Venereum(LGV(LGV))
C. trachomatisC. trachomatis
Sexually TransmittedSexually Transmitted
First stageFirst stage
– Small painless vesicular lesion at infection siteSmall painless vesicular lesion at infection site
– Fever, headache and myalgiaFever, headache and myalgia
Second stageSecond stage
– Inflammation of draining lymph nodesInflammation of draining lymph nodes
– Fever, headache and myalgiaFever, headache and myalgia
– Buboes (rupture and drain)Buboes (rupture and drain)
– ProctitisProctitis
– Ulcers or ElephantiasisUlcers or Elephantiasis

25. Patient with LGVPatient with LGV
Bilateral inguinal buboesBilateral inguinal buboes
(arrows)(arrows)

26. C. trachomatisC. trachomatis - Diagnosis- Diagnosis
CytologyCytology
– IntracellularIntracellular
Inclusion bodyInclusion body
CultureCulture
– HeLa, Mc CoyHeLa, Mc Coy
cell linecell line
– Yolk Sac ChickYolk Sac Chick
embryoembryo
– Iodine stainingIodine staining
inclusionsinclusions
Iodine-stained inclusion bodies

27. C.C. trachomatis - Diagnosistrachomatis - Diagnosis
Antigen detectionAntigen detection (ELISA or IF)(ELISA or IF)
– Group specific LPSGroup specific LPS
– Strain specific outer membrane proteinsStrain specific outer membrane proteins
SerologySerology
– CF, ELISA, MIFCF, ELISA, MIF
– Can’t distinguish between current or pastCan’t distinguish between current or past
infectioninfection
– Detection of high titer IgM antibodies can beDetection of high titer IgM antibodies can be
helpfulhelpful
Nucleic acid probesNucleic acid probes
– Several kits availableSeveral kits available
– May eventually replace cultureMay eventually replace culture

28. C. trachomatisC. trachomatis - Treatment and- Treatment and
PreventionPrevention
Tetracycline, erythromycin andTetracycline, erythromycin and
sulfonamidessulfonamides
Vaccines are of little valueVaccines are of little value
Treatment coupled with improvedTreatment coupled with improved
sanitationsanitation
Safe sexual practicesSafe sexual practices
Treatment of patients and their sexualTreatment of patients and their sexual
partnerspartners

29. Chlamydophilia (Chlamydia)Chlamydophilia (Chlamydia)
psittacipsittaci
Psittacosis (Parrot fever)Psittacosis (Parrot fever)
OrnithosisOrnithosis

30. Pathogenesis -Pathogenesis - C. psittaciC. psittaci
Inhalation of organisms in bird droppingsInhalation of organisms in bird droppings
– Person to person transmission is rarePerson to person transmission is rare
Hematogenous spread to spleen and liverHematogenous spread to spleen and liver
– Local necrosis of tissueLocal necrosis of tissue
Hematogenous spread to lungs and otherHematogenous spread to lungs and other
organsorgans
Lymphocytic inflammatory responseLymphocytic inflammatory response
– Edema, infiltration of macrophages, necrosis andEdema, infiltration of macrophages, necrosis and
occasionally hemorrhageoccasionally hemorrhage
– Mucus plugs may develop in alveoliMucus plugs may develop in alveoli
Cyanosis and anoxiaCyanosis and anoxia

31. Epidemiology -Epidemiology - C. psittaciC. psittaci
Organisms present in birds (symptomaticOrganisms present in birds (symptomatic
or asymptomatic)or asymptomatic)
– Tissue, feces, feathersTissue, feces, feathers
Primarily an occupational diseasePrimarily an occupational disease
– Veterinarians, poultry workers, zoo keepers,Veterinarians, poultry workers, zoo keepers,
pet shop workerspet shop workers

32. OrnithosisOrnithosis
Uncomplicated InfectionUncomplicated Infection
Incubation periodIncubation period
– 1-2 weeks1-2 weeks
Fever, chills, headache, nonproductiveFever, chills, headache, nonproductive
cough, mild pneumonitiscough, mild pneumonitis
RecoveryRecovery
– 5-6 weeks5-6 weeks

33. OrnithosisOrnithosis
Complicated InfectionComplicated Infection
Incubation periodIncubation period
– 1-2 weeks1-2 weeks
Fever, chills, headache, nonproductive cough, mentalFever, chills, headache, nonproductive cough, mental
confusion, pneumonitis, cyanosis, jaundiceconfusion, pneumonitis, cyanosis, jaundice
Prolonged RecoveryProlonged Recovery
– 7-8 weeks7-8 weeks

34. Laboratory Diagnosis -Laboratory Diagnosis - C. psittaciC. psittaci
Serology (Complement fixation test)Serology (Complement fixation test)
– Fourfold rise in titerFourfold rise in titer

35. Treatment and Prevention -Treatment and Prevention - C. psittaciC. psittaci
Tetracycline or erythromycinTetracycline or erythromycin
Quarantine of imported birdsQuarantine of imported birds
Control of bird infectionControl of bird infection
– Antibiotic supplementation of foodAntibiotic supplementation of food

36. Chlamydophilia (Chlamydia)Chlamydophilia (Chlamydia)
pneumoniaepneumoniae
TWAR agentTWAR agent
– Taiwan (TW-183) and acute respiratoryTaiwan (TW-183) and acute respiratory
isolate (AR-39)isolate (AR-39)
Atypical pneumoniaAtypical pneumonia
Atherosclerosis ?Atherosclerosis ?

37. Pathogenesis -Pathogenesis - C. pneumoniaeC. pneumoniae
Person to person spreadPerson to person spread
– Respiratory dropletsRespiratory droplets
Bronchitis, sinusitis and pneumoniaBronchitis, sinusitis and pneumonia

38. Epidemiology -Epidemiology - C. pneumoniaeC. pneumoniae
Common infection (200,000 - 300,000 cases perCommon infection (200,000 - 300,000 cases per
year)year)
Primarily in adultsPrimarily in adults
Most infections are asymptomaticMost infections are asymptomatic
Associated with crowded conditionsAssociated with crowded conditions
– Schools, military basesSchools, military bases etc.etc.
Association with atherosclerosisAssociation with atherosclerosis
– Organisms in diseased arteriesOrganisms in diseased arteries
– AntibodiesAntibodies

39. Clinical Syndrome -Clinical Syndrome - C. pneumoniaeC. pneumoniae
Mild or asymptomatic diseaseMild or asymptomatic disease
Pharyngitis, bronchitis, persistent coughPharyngitis, bronchitis, persistent cough
and malaiseand malaise
Pneumonia may developPneumonia may develop
– Usually a single lobeUsually a single lobe

40. Laboratory Diagnosis -Laboratory Diagnosis - C. pneumoniaeC. pneumoniae
SerologySerology
– Fourfold rise in titerFourfold rise in titer

41. Treatment and Prevention -Treatment and Prevention - C.C.
pneumoniaepneumoniae
Tetracycline or erythromycinTetracycline or erythromycin
Difficult to prevent transmissionDifficult to prevent transmission
No vaccineNo vaccine