Chlamydia

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Etiologia - Chlamydia trachomatis
  • Unusual bacteria
  • Obligate intracellular (cannot make ATP - uses host cell ATP)
    • Infection of epithelial cells lead to granulomatous response
  • Not seen on gram stain - peptidoglycan layer lacks muramic acid
  • Elementary body is the infectious form of the bacteria (has attachment proteins) - gets into the host cells anc converts into reticulate body which replicates and then converts back to elementary body to infect more cells
 
Apresentação clínica
  • Trachoma - serotypes A, B, Ba and C
    • Developing endemic countries
    • Follicular conjunctivitis leading to scarring and inturned eyelashes leading to corneal scarring and blindness
  • STDs - serotypis D-K (“Dick”)
    • Nongonococcal urethritis, cervicitis, PID, proctitis, protatitis
      • Most common cause of urethritis
      • Most asymptomatic
    • Inclusion conjunctivitis
    • Pneumonia in neonates (staccato cough)
 
Diagnóstico
  • PCR (for C. Trachomatis & N. Gonorrhoea)
  • Serology not recommended
  • Test of cure
    • Not recommended if used doxycycline in uncomplicated patients
    • Recommended if pregnant or persistent symptoms. Best timing 4 weeks.
  • Cannot be cultured on inert media - intracellular (use tissue cultures or embyonated eggs)
  • Self collected swabs similar sensitivity, more convenient
  • Gram stain
 
Tratamento
  • No evidence of any stable homotypic genetic and phenotypic anti microbial resistance in C. Trachomatis
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  • Treatment failures: poor compliance, reinfection, TOC too early
  • Partner treatment: expedited partner therapy without testing? STIs other than chlamydia will be missed.
  • Adolescentes e adultos
    • 1st line
      • Doxycycline 100mg 2id 7 dias
    • 2nd line
      • Azithromycin 1g stat - causes problems in resistance to other organisms like gonorrhoea and mycoplasma
      • Levofloxacin 500mg id 7 dias
    • 3rd line
      • Ofloxacina 200mg 2id 7 dias
      • Erythomycin 500mg 2id 7 dias
      • Josamicina 500mg 3id 7 dias (ou 1000mg 2id 7 dias)
  • In pregnancy ou lactemtes
    • 1st line: azithromycin 1g toma única
    • 2nd line: amoxicillin 500mg 3id 7 dias
    • 3rd line
      • Eritromicina 500mg 4id 7 dias (ou 500mg 2id 14 dias)
      • Josamicina 500mg 3id 7 dias (ou 1000mg 2id 7 dias)
  • Recém nascidos e crianças com peso inferior a 45kg
    • 1ª linha: eritromicina 50mg/kg/dia em 4 tomas diárias, 14 dias
    • 2ª linha: azitromicina 20mg/kg/dia id 3 dias
  • Crianças com peso superior a 45kg
    • Azitromicina 1g toma única
    • Doxicicina 100mg 2id 7 dias
 
Prevention
  • Screening
    • Controversial
    • No evidence that screening for chlamydia and gonorrhoea in asymptomatic patients lowers the prevalence of these infections in MSM.
      • Argument in favor of not testing: we also don’t test for meningococcal carriage in oropharix
  • DoxyPEP
  • Local pentamidine prophylaxis against Chlamydia trachomatis
  • Vaccination
    • No vaccine currently available
    • 1960-70 - studies with live attenuated vaccine showed incomplete protection and increased inflammation, which could lead to infertility. Later efforts were much more cautious
    • Vary candidates are being studied (mRNA vaccine, Trachoma “prime-pull” vaccine strategy)