Chlamydia are divided into three species

1. C. psittaci- causes psittacosis, an interstitial pneumonia contracted from birds
2. C. pneumoniae- causes pneumonia, bronchitis , and pharyngitis in school aged children
3. C. trachomatis-spectrum of diseases related to the serotype
1. ocular trachoma in developing countries- a common cause of blindness
2. lymphogranuloma venereum- invasive lymphatic disease
3. genital infections including urethritis, epididymitis, cervicitis, and salpingitis. Transmission to newborns at delivery from infected mothers can cause infant conjunctivitis and pneumonia .

1. ~50% of infected pregnant women will have neonate that is colonized. About 50% of these neonates will develop conjunctivitis. These neonates will also have + nasopharyngeal colonization.
2. Usually develops 5-14 days after birth.
3. Initially watery discharge that becomes purulent. Then will develop lid swelling, conjunctival erythema and swelling. 
4. Untreated may last for weeks but there is no scar formation and resultant blindness.
5. Must differentiate from N. gonorrhea infection which starts earlier and is more rapidly progressive.
6. Diagnosis
1. Culture organism from the conjunctiva or nasopharynx. Need to get specimen with cells because organism is intracellular purulent material may not have organisms present
2. DFA, EIA, PCR may be available in some labs.
7. Treatment
1. 50 mg/kg. per day of oral erythromycin for 14 days. ~20% failure rate and may need retreatment.
2. Treat mother and her sexual partner as well
3. topical treatment is unnecessary 
8. Erythromycin and Silver Nitrate are not effective prophylaxis. Only prevention is treatment of pregnant infected women. 

1. 5-20% of infected neonates will develop pneumonia.
2. usually between 1-3 months of age.
3. ~50% will have a history of conjunctivitis
4. Insidious onset with stuffy nose, cough (staccato), tachypneic, and not toxic looking. Often afebrile. Chest may have diffuse crackles and usually no wheezing. 
5. Chest radiograph has bilateral interstitial infiltrates and hyperinflation. 
6. Peripheral eosinophilia 
7. Occasionally present with apnea and respiratory failure
8. Diagnosis
1. Nasopharyngeal culture or other nonculture methods (DFA, EIA)
9. Treatment
1. 14 days of oral erythromycin-50mg/kg. per day
10. May be associated with later development of reactive airway disease.

1. Darville T. Chlamydia. Pediatrics in Review. 1998; 19(3):85-91.
2. Hammerschlag M.  Chlamydia Pneumonia Contemporary Pdiatrics May 1999
3. Hammerschlag M. Chlamydia trachomatis and Chlamydia pneumonia Infections in Children and Adolescents. Pediatrics in Review Februaruy 2004