Chlamydiae

Chlamydiae

1. GENITAL, OCULAR & RESPIRATORY PATHOGENS

2. GRAM - COCCI

3. OBLIGATE INTRACELLULAR (ONLY LIVE INSIDE HOST)

4. UNIQUE DEVELOPMENTAL CYCLE: TWO CELLULAR FORMS

   • ELEMENTARY BODIES (SMALLER)
     • INFECTIOUS= INVASIVE CELL (LIKE VIRION)
     • NO CELL DIVISION; NO METABOLIC ACTIVITY
     • STAGES OF INFECTION:
       • 1. EB ATTACH TO HOST CELL
         • 2. ENDO/PHAGOCYTOSIS INDUCED BY BACTERIUM
           • EB IS TOXIC; >100 WILL KILL HOST CELL
             • RESULTING ENDOSOME REMAINS INTACT: LYSIS PROHIBITED BY THE EB UNTIL JUST BEFORE RELEASE OF NEW EBs
               • EBs "GERMINATE" INTO RETICULATE BODIES; ENDSOME INTACT
                 • +/- 30 HOURS
   • RETICULATE BODIES (LARGER)
     • CELL DIVISION: BINARY FISSION
     • NON-INFECTIOUS CELL
     • 1. RBs RAID HOST CELL ATP PRODUCTION: C. TRACHOMATIS GENOME HAS ATP SYNTHESIS GENES, BUT UNCLEAR IF EXPRESSED
       • 2. RBs UNDERGO BINARY FISSION; +/- 3 HOURS/GENERATION
         • 3. RBs CONVERT INTO NEW EBs
           • 4. NEW GENERATION RELEASED FROM COMPROMISED HOST CELL: 100-1000 NEW EBs
             • 5. HOST CELL DEATH UPON RELEASE NEW GENERATION OF EBs
     • IF INTERFERON-GAMA OR PENICILLIN OR NUTRIENT LIMITATION:
       • RBs WILL GROW IN SIZE, AND STAY IN A PERSISTENCE STATE UNTIL ENVIRONMENT BECOMES SUITABLE
     • TYPE III SECRETION SYSTEM

5. FIRST MOST COMMON BACTERIAL STI IN US

6. HUMAN AND ANIMAL RESERVOIR

7. INVADE

8. LACK OF PEPTIDOGYLCAN CELL WALLS (?)

   • UNABLE TO FIND, BUT SEQUENCING REVEALS OTHERWISE

9. NONMOTILE

10. SMALL IN SIZE AND GENOME

    • THEY DON'T NEED A LARGE GENOME COMPARED TO E. COLI BECAUSE THEY RELY ON THE HOST, WHILE E. COLI NEEDS TO HAVE THE CAPABILITY TO LIVE OUTSIDE THE HOST

11. AUXOTROPHIC FOR SEVERAL AMINO-ACIDS AND THREE OF THE FOUR NUCLEOTIDE TRIPHOSPHATES ("ENERGY PARASITES")

12. "STEALTH PATHOGENS" SO CAN HIDE FROM IMMUNE SYSTEM

    • HOSTS: HUMANS / ANIMALS / BIRDS
    • TWO GENUSES: CHLAMYDIA AND CHLAMYDOPHILA

13. C. trachomatis

    • best studied strain
    • varieties of this cause STDs / EYE INFECTIONS / RESPIRATORY INFECTIONS IN HUMANS
    • CHLAMYDIA TRACHOMATIS BIOVAR TRACHOMA SEROVARS A-C
      • TRACHOMA (EYE INFECTION)
        • CHRONIC CONJUNCTIVITIS CAUSED BY THIS
        • LEADING CAUSE TO BLINDNESS GLOBALLY
        • RARE IN US
        • COMMON IN SUB-SAHARA AFRICA, MIDDLE EAST AND ASIA
        • AT LEAST 50 MILL CASES, 3-10 MILLION BLIND
          • VISUAL LOSS OCCURS 15-20 YEARS AFTER INITIAL INFECTION
        • SYMPTOMS
          • EYE DISCHARGE
            • SWOLLEN EYELIDS
            • TRICHIASIS (TURNED-IN EYELASHES)
              • SWELLING OF LYMPH NODES IN FRONT OF THE EARS
                • SENSITIVITY TO BRIGHT LIGHTS
                  • INCREASED HEART RATE
                    • EAR, NOSE, THROAT COMPLICATIONS
          • TREATMENT
            • AZITHROMYCIN
            • TETRACYCLIN
      • C. trachomatis biovar trachoma servoars D-K
        • C. trachomatis biovar lymphogranuloma venereum (LGV) L1-L3
          • Invasive sexually transmitted infections
            • not as common and spreads to other places in the body
        • STI
    • INFECTS MAINLY MUCOSAL (EPITHELIAL) MEMBRANES (I.E. CERVIX, RECTUM, URETHRA, THROAT, CONJUNCTIVA)
    • TRANSMISSION
      • SEXUALLY TRANSMITTED
      • DURING VAGINAL BIRTH
      • TRANSFER FROM INFECTED SECRETIONS FROM GENITALS TO HANDS TO EYES (TRACHOMA)
    • VIRULENCE FACTORS
      • TYPE III SECRETION SYSTEM
      • TRANSLOCATED ACTIN RECRUITING PROTEIN (TARP) FOR MOVEMENT
      • CHLAMYDIAL PROTEASE-LIKE ACTIVITY FACTOR (CPAF)
      • MAJOR OUTER MEMBRANE PROTEIN (MOMP)
      • PUTATIVE AUTOTRANSPORTER PROTEINS
    • SYMPTOMS
      • IF PRESENT, DEVELOP 1-3 WEEKS AFTER INFECTION
      • IN WOMEN: 75% ASYMPTOMATIC
        • DISCHARGE (MOST COMMON)
          • DYSURIA
            • PELVIC PAIN
              • BLEEDING BETWEEN PERIODS OR AFTER INTERCOURSE
      • IN MEN: 50% ASYMPTOMATIC
        • DISCHARGE
          • DYSURIA
            • REDNESS AT TIP OF PENIS
    • RISK FACTORS
      • UNSAFE SEX AND MULTIPLE PARTNERS
      • DIAGNOSTICS
        • SWAB SPECIMENS (CERVIX OR URETHRA)
        • NUCLEIC ACID AMPLIFICATION TESTS (NAAT)
        • THROAT OR ANAL CHLAMYDIA DIAGNOSED BY BACTERIAL CULTURES
      • TREATMENT
        • ANTIBIOTICS
          • DOXYCYCLINE: 7 DAYS
          • OFLOXACIN: 7 DAYS
          • ERYTHROMYCIN: 7 DAYS
          • AZINTHROMYCIN: SINGLE DOSE, MUST BE COMPLETELY ABSTINENT FOR 7 DAYS AFTER TAKING
        • PREVENTION
          • NO VACCINE
            • CONDOMS
              • NONOXYNOL-9: SPERMICIDE DOES NOT PROVIDE PROTECTION AGAINST INFECTION

14. OLD INFECTION, BUT STI AROSE IN 1970s (FIRST DESCRIBED)

    • EYE INFECTIONS OLD (EGYPT IN 15 B. C. ), ANCIENT CHINA AND MESOPOTAMIA
      • CHLAMYDIA BECAME REPORTABLE TO THE CDC IN 1986

15. IN 2006= OVER 1 MILLION CASES/YR (2.9 CDC)

    • WORLD WIDE (92 MILL IN WORLD IN 1999) 140 MILLION NOW NOT INCLUDING EYE INFECTIONS

16. C. psittaci

    • CAUSES HUMAN PSITTACOSIS (ORNITHOSIS), A ZOONOTIC PNEUMONIA
    • 100-200 CASES/YR US
    • DIAGNOSIS: BY BLOOD-BASED ASSAY
      • CHECKING FOR ANTIBODY TITER
      • TREATMENT: DOXYCYCLINE, TETRACYCLINE, AZITHROMYCIN, ERYTHROMYCIN

17. QUESTIONS:

    • FALSE: CHLAMYDIAL CELLS CONTAIN A POLAR FLAGELLUM
      • TRUE: CHLAMYDIAE CONTAIN OUTER MEMBRANE
        • FALSE: CHLAMYDIA IS AN OLD STB WHICH FIRST REPORTED IN ANCIENT EGYPT
    • NOT CORRECT: INDIVIDUAL WHO HAVE DEVELOPED TRACHOMA CANNOT DEVELOP CHLAMYDIA