Chlamydial pneumonia is a respiratory tract infection affecting the lungs, causing inflammation and difficulty breathing. This form of pneumonia can range from mild to serious, impacting individuals of all ages.
What is Chlamydial Pneumonia?
Chlamydial pneumonia is caused by the bacterium Chlamydia trachomatis, which is distinct from Chlamydia pneumoniae, another bacterial species that commonly causes respiratory infections in school-aged children and young adults. While Chlamydia trachomatis is widely known for causing sexually transmitted infections, certain strains are responsible for this lung infection. It is an obligate intracellular bacterium, meaning it requires a host cell to replicate.
This form of pneumonia is most frequently observed in infants, often referred to as infant pneumonia of the newborn. An estimated 12,000 cases of pneumonia due to C. trachomatis occur each year in infants. Although less common, adults, particularly those who are immunocompromised, can also develop chlamydial pneumonia.
How It Spreads and Its Symptoms
The primary mode of transmission for chlamydial pneumonia, especially in infants, is vertical transmission from an infected mother to her newborn during vaginal childbirth. Approximately 5-22% of pregnant individuals have C. trachomatis infection of the cervix. Of neonates born to infected individuals, 30-50% show evidence of infection, and about 11-20% may develop symptomatic pneumonia before 8 weeks of age.
For adults, transmission is less common but can occur through respiratory droplets, particularly in cases involving specific strains of Chlamydia trachomatis. Symptoms in infants manifest between 1 to 3 months of age, often characterized by a distinctive “staccato” cough, nasal congestion, and a lack of fever. Conjunctivitis (pink eye) may also be present in about half of infant cases, and infants are symptomatic for three weeks or longer before diagnosis.
Adults with chlamydial pneumonia may experience symptoms such as a persistent cough, fever, and shortness of breath. These symptoms can be milder or atypical compared to other forms of pneumonia, making diagnosis challenging. Nonspecific symptoms like fatigue, headache, and a sore throat may also occur, with symptoms taking 3 to 4 weeks to appear after exposure and lasting for weeks.
Diagnosis and Treatment Approaches
Diagnosing chlamydial pneumonia involves a combination of clinical evaluation and specific laboratory tests. Healthcare providers consider the patient’s symptoms and medical history, especially in infants born to mothers with a history of chlamydial infection. Chest X-rays can reveal characteristic patterns of lung inflammation, although these findings are not always specific to chlamydial pneumonia.
Laboratory tests are essential for confirming the presence of Chlamydia trachomatis. Polymerase Chain Reaction (PCR) testing of respiratory secretions, such as nasopharyngeal swabs or tracheal aspirates, is a common and effective method for detecting the bacterium’s genetic material. While tissue culture is considered a definitive diagnostic test, non-culture tests like direct fluorescent antibody (DFA) and nucleic acid amplification tests (NAATs) can also be used.
Treatment for chlamydial pneumonia involves antibiotics, with macrolides being the preferred class of drugs. For infants, erythromycin or azithromycin is commonly prescribed. For adults, azithromycin, doxycycline, or levofloxacin may be used, often with specific loading and daily doses. Early diagnosis and appropriate antibiotic treatment are important for preventing complications and ensuring a favorable outcome, particularly in infants.
Steps for Prevention
Preventing chlamydial pneumonia largely focuses on addressing Chlamydia trachomatis infection in pregnant individuals to prevent transmission to newborns. Routine screening for Chlamydia trachomatis during prenatal care is a key preventative measure. If an infection is identified, treating it before delivery can significantly reduce the risk of vertical transmission to the infant.
For adults, general preventative measures against Chlamydia trachomatis infection, such as practicing safe sexual behaviors, indirectly help reduce the risk of chlamydial pneumonia. While there is no specific vaccine for Chlamydia trachomatis or Chlamydia pneumoniae, good hygiene practices, including frequent handwashing and covering coughs and sneezes, can help prevent the spread of respiratory germs.