Neonatology

Chlamydia of the Newborn

Organisms

C. psittaci: Causes psittacosis, an interstitial pneumonia contracted from birds

C. pneumoniae: Causes pneumonia, bronchitis , and pharyngitis in school aged children

C. trachomatis: Spectrum of diseases related to the serotype

Ocular trachoma in developing countries. This is a common cause of blindness.
Lymphogranuloma venereum is caused by invasive lymphatic disease
Genital infections including urethritis, epididymitis, cervicitis, and salpingitis are sexually transmitted.
Transmission to newborns from infected mothers occurs at delivery and can cause infant conjunctivitis and pneumonia .

Transmitted to newborns primarily by exposure to the infected mother’s vaginal flora during birth, although there is a small risk associated with C-section.
15 serovariants of C. Trachomatis, although newborn infection is usually caused by serovariants B and D through K.
/the prevalence of C. Trachomatis in pregnant women ranges between 2 and 20% with the highest prevalence in adolescent and young adult women. Risk factors for infection include being sexually active, having multiple sexual partners, non-use of barrier contraceptives, concurrent or prior sexually transmitted disease, and anatomic factors.
The risk of transmission of C. Trachomatis to a newborn from a mother with chlamydial cervicitis is between 50 and 70%. This results in newborn conjunctivitis between 20 and 50% of the time and newborn pneumonia between 5 and 30% of the time (i.e. not all colonization leads to infection).

Conjunctivitis is the most common neonatal manifestation of C. Trachomatis infection.
The incubation period is 5-14 days after birth. Presentation before 5 - 14 days is rare, but has occurred with premature rupture of membranes.
Initially the disease presents as watery discharge that becomes purulent.
This can (but does not always) progress to marked swelling of eyelids with red and thickened conjunctiva (chemosis).
A pseudomembrane may form over the conjunctiva, which can become friable, resulting in bloody discharge.
A membrane of granulation tissue may form after about two weeks if the condition is left untreated.
Untrested infection may last for months and cause corneal and conjunctival scarring.
N. Gonorrhea conjunctivitis presents earlier and progresses more rapidly, but must be considered in the differential diagnosis.

5 to 30% of infected neonates will develop pneumonia. Approximately half of these infants will have a history of C. Trachomatis conjunctivitis.
The condition is generally recognized between 4 and 12 weeks of age, although most infants are symptomatic as early as 8 weeks of age.
Cough and nasal congestion without discharge are common, although discharge can be thick.
Onset is insidious and characteristic features include a staccato cough, tachypnea. Rales is common upon auscultation, but wheezing is not. The liver and spleen may be palpable secondary to hyperinflated lungs.
The patient is usually afebrile, and does not appear particularly ill.
Premature neonates have had apnea spells secondary to Chlamydia pneumonia.
WBC is normal, but eosinophils can be elevated.
Arterial blood gas shows moderate hypoxemia.
Chest X-ray shows hyperinflation with bilateral, symmetrical interstitial infiltrates.

Culture of the organism from the conjunctiva or nasopharynx remains the gold standard of diagnosis for conjunctivitis and pneumonia..
Nucleic acid amplification tests (NAATs) can also be used to amplify the organisms DNA or RNA by PCR. These have been shown to have high sensitivity and specificity compared to culture but are not currently approved by the FDA for neonates.
Direct fluorescent antibody and immunoassay tests are antigen detection methods that have largely been replaced by NAATs. Sensitivities and specificities are about 97 and 98% respectively. These are FDA approved.
A serum antibody titer of C. trachomatis > 1:32 is diagnostic. This is NOT helpful for diagnosing conjunctivitis.

The only prevention is prenatal treatment of the pregnant mother. Specifically, erythromycin and silver nitrate given to prevent N. Gonorrhea in neonates is not helpful in treating C. Trachomatis.
Mother’s who received prenatal care are routinely tested for C. Trachmatis at their first visit. Mothers engaged in risky behavior should be retested during the third trimester.
The AAP and CDC recommend erythromycin 50 mg/kg/day PO divided into four doses for 14 days for either conjunctivitis or pneumonia. Azithromycin may also be used.
Erythromycin is effective in 80 – 90% of conjunctivitis cases. Infants who fail the first course must be given a second (identical) course. Therefore, careful follow-up is required by the treating physician.
Erythromycin has been shown to increase incidence of infantile hypertrophic pyloric stenosis.

Darville, T. Chlamydia Infctions. In: Infectious Diseases of the Fetus and Newborn Infant, 7, Remington, JS, Klein JO, Wilson, CB, Nizet V, MaldonadoYA (Eds), Elsevier Saunders, Philadelphia 2010. p.600.
Mordhorst CH, Dawson C. Sequelae of neonatal inclusion conjunctivitis and associated disease in parents. Am J Ophthalmol 1971; 71:861.