Respiratory chlamydia: symptoms, diagnosis, treatment

Respiratory chlamydia is not a single, strictly defined disease or a separate, official diagnosis. This term can refer to respiratory tract infections caused by several species of bacteria in the genus Chlamydia. Most commonly, it refers to Chlamydia pneumoniae, which is airborne and causes pharyngitis, laryngitis, bronchitis, or community-acquired pneumonia. [1]

Chlamydia pneumoniae is fundamentally different from Chlamydia trachomatis, which causes urogenital chlamydia.Chlamydia pneumoniae infection is spread by coughing and sneezing, not by sexual contact. Therefore, a positive Chlamydia pneumoniae antibody test does not indicate the presence of a sexually transmitted infection and is not a basis for testing a sexual partner for urogenital chlamydia. [2]

Another form of respiratory chlamydial infection occurs in infants. Chlamydia trachomatis can be transmitted to a child from an infected mother during birth and, several weeks later, cause subacute pneumonia. This infection typically develops between 1 and 3 months of age and has features not seen in common pneumonia in adults. [3]

Chlamydial respiratory infections sometimes include ornithosis, or psittacosis, caused by Chlamydia psittaci. Humans become infected primarily by inhaling dust containing dried secretions or droppings of infected birds. The disease can manifest as a flu-like infection or severe pneumonia. [4]

Therefore, before making a diagnosis, it is necessary to clarify the patient's age, the nature of symptoms, contact with sick people, pregnancy and childbirth history, as well as possible contact with domestic, farm, or wild birds. The term "respiratory chlamydia" alone is insufficient for selecting testing and treatment. [5]

Infection variant	Pathogen	Main group of patients	Route of transmission
Human respiratory infection	Chlamydia pneumoniae	Schoolchildren, teenagers, adults	Cough and sneeze drops
Infant pneumonia	Chlamydia trachomatis	Children 1-3 months	During childbirth
Ornithosis or psittacosis	Chlamydia psittaci	People in contact with birds	Inhalation of contaminated dust
Urogenital chlamydia	Chlamydia trachomatis	Sexually active people	Sexual tract
Trachoma	Selected variants of Chlamydia trachomatis	Residents of endemic regions	Eye and nasal discharge

The table content is based on current clinical data from the US Centers for Disease Control and Prevention. [6] [7] [8]

How is the infection transmitted and who gets sick most often?

Chlamydia pneumoniae is transmitted from person to person through small droplets produced by coughing and sneezing. Infection is possible by inhaling these droplets, as well as by touching a contaminated surface and then touching your mouth or nose. The bacteria damage the mucous membranes of the throat, trachea, and bronchi, and as the infection spreads, it can affect lung tissue. [9]

The incubation period is usually long—about 3-4 weeks. A person can spread the bacteria before symptoms appear and remain infectious for several weeks after the illness begins. This helps explain why outbreaks in organized groups can persist for a long time. [10]

Primary infection most often occurs in school-age children or young adults. Recurrent infections are possible, as a previous infection does not provide reliable lifelong protection. In people over 65, reinfection and severe pneumonia are more common than in younger patients. [11]

The risk of spread is increased in places where people are in close contact for long periods of time: schools, dormitories, military units, hospitals, long-term care facilities, and prisons. However, the infection can also spread from person to person without any noticeable symptoms. [12]

Infant pneumonia caused by Chlamydia trachomatis is not transmitted by airborne droplets from an infected adult. The infant typically acquires the bacteria during birth through contact with the mother's infected cervix. Therefore, the presence of chlamydial conjunctivitis or pneumonia in an infant requires examination of the mother and her sexual partner. [13]

Factor	How does it affect risk?
School age or young adulthood	Often the first infection occurs
Age over 65 years	Higher risk of recurrent and severe infection
Living or working in a close-knit team	Facilitates transmission by droplet transmission
Long-term contact with a sick person	The risk is higher than with brief casual contact
No symptoms at the source	Does not exclude transmission
Untreated chlamydia in a pregnant woman	Increases the risk of infection in the infant
Contact with birds and their droppings	Increases the risk of ornithosis

Data on transmission, incubation period, and risk groups are based on data from the US Centers for Disease Control and Prevention. [14] [15]

Symptoms of Chlamydia pneumoniae infection

Most respiratory infections caused by Chlamydia pneumoniae are asymptomatic or mild. If symptoms do occur, the illness often begins gradually rather than suddenly. A person may experience fatigue, headache, mild fever, and sore throat for several days before a severe cough develops. [16]

Early symptoms include a runny or stuffy nose, sore throat, hoarseness, weakness, and headache. Hoarseness and signs of laryngitis are more common in pneumonia caused by Chlamydia pneumoniae than in many other bacterial pneumonias.[17 ]

The cough usually develops slowly and can persist significantly longer than other symptoms. Even after proper treatment, the cough, fatigue, and malaise sometimes persist for several weeks or months. This does not always mean that the bacteria are still present or that the patient necessarily needs a repeat course of antibiotics. [18]

If the lower respiratory tract is affected, bronchitis and pneumonia are possible. A more severe cough, chest pain or discomfort, shortness of breath, rapid breathing, and fever develop. However, it is impossible to distinguish Chlamydia pneumoniae from a viral infection, mycoplasma, pneumococcal, or other community-acquired pneumonia based on symptoms alone. [19]

Severe complications are rare, but brain inflammation, heart muscle inflammation, and worsening of asthma have been reported. Researchers have studied the possible association of chronic infection with atherosclerosis, Alzheimer's disease, multiple sclerosis, and other conditions, but a causal link to these diseases has not been confirmed. [20]

Manifestation	How typical is it?
Gradual start	Typically
Slight fever	Often
Sore throat	Often
Hoarseness	Relatively typical
A slowly worsening cough	Very characteristic
Long-term weakness	Possible
Shortness of breath and chest pain	Possible with pneumonia
High temperature and severe intoxication	Possible, but not required

The table reflects the most common clinical manifestations listed in the current review by the US Centers for Disease Control and Prevention. [21] [22]

Chlamydial pneumonia in newborns and infants

Chlamydia trachomatis pneumonia typically develops between 1 and 3 months of age, not immediately after birth. The disease often has a subacute course: the temperature may remain normal, but the cough and rapid breathing gradually worsen. The absence of a high fever does not mean the condition is safe. [23]

The classic symptom is a repetitive, hacking cough, called a staccato cough in English-language guidelines. It consists of a series of short coughing bursts. Rapid breathing, lung hyperinflation, and bilateral diffuse changes on a chest X-ray may also be observed. [24]

Blood tests often reveal an increased number of eosinophils, a type of white blood cell. However, this finding is not mandatory and cannot independently confirm the diagnosis. The diagnosis is established based on the child's age, clinical presentation, examination results, and the mother's risk of chlamydia. [25]

In some children, pneumonia is preceded by chlamydial conjunctivitis, which appears 5-12 days after birth. However, the absence of ocular discharge does not rule out a respiratory infection. Chlamydia trachomatis can be asymptomatically present on the mucous membranes of the nasopharynx, eyes, rectum, and genitourinary system of a newborn. [26]

Every child aged 1-3 months with suspected pneumonia should be examined by a pediatrician. It is especially important to inform the doctor if the mother was diagnosed with chlamydia during pregnancy, was not screened, or had no confirmed cure after treatment. [27]

Sign in an infant	Meaning
Age 1-3 months	Typical period of appearance
A hacking, repetitive cough	A characteristic symptom
Normal or slight temperature	It is often found
Rapid breathing	Sign of lower respiratory tract damage
Overinflation of the lungs	Possible radiographic sign
Bilateral scattered changes	Possible on radiograph
Elevated eosinophils	A common but nonspecific finding
Conjunctivitis after birth	Supports suspicion of chlamydial infection

Clinical signs and age characteristics are given according to current recommendations for chlamydial infections in newborns. [28]

Ornithosis: a respiratory infection caused by Chlamydia psittaci

Ornithosis, or psittacosis, is caused by the bacterium Chlamydia psittaci, which primarily infects birds. Humans are most often infected by inhaling dust containing dried particles of bird droppings or respiratory secretions. Birds that can be infected include parrots, cockatiels, pigeons, chickens, turkeys, ducks, and other birds.[29]

Symptoms usually begin 5-14 days after exposure, but sometimes occur later. The most typical symptoms are high to moderate fever, chills, severe headache, muscle aches, and a dry cough. Some patients develop pneumonia. [30]

Birds don't necessarily appear sick. Infected birds, without any outward signs of illness, can shed the bacteria in their droppings and respiratory secretions. Therefore, contact with birds, cage cleaning, and work in a pet store, poultry farm, veterinary clinic, or processing plant are important factors in diagnosis. [31]

With proper treatment, most people make a full recovery. However, severe pneumonia, inflammation of the heart valves, and damage to the liver, nervous system, or brain are possible. With timely antibiotic therapy, the mortality rate is less than 1 in 100 cases. [32]

Ornithosis cannot be reliably distinguished from Chlamydia pneumoniae, influenza, coronavirus infection, Legionellosis, or mycoplasma pneumonia based solely on cough and fever. The main diagnostic clue is the epidemiological history—recent contact with birds or bird droppings. [33]

Sign	Chlamydia pneumoniae	Ornithosis
Source	A sick person	Birds
The main route	Cough and sneeze drops	Inhalation of dust from bird droppings
Incubation period	Usually 3-4 weeks	More often 5-14 days
Start	Often gradual	Often more acute
Cough	Gradually increasing	Often dry
Headache and muscle pain	Possible	Often expressed
Professional risk	Groups and institutions	Working with birds

The comparison is based on the US Centers for Disease Control and Prevention data on Chlamydia pneumoniae and psittacosis.[34] [35]

Diagnosis of respiratory chlamydia

The clinical manifestations of Chlamydia pneumoniae are nonspecific. Gradual onset, hoarseness, and a persistent cough suggest infection but do not confirm it. Similar symptoms are seen with respiratory viruses, Mycoplasma pneumoniae, whooping cough, pneumococcal infection, and other causes of bronchitis and pneumonia. [36]

Molecular methods, primarily nucleic acid amplification tests (NAATs), including real-time polymerase chain reaction (RT-PCR), are preferred for diagnosing acute Chlamydia pneumoniae infection. In clinical laboratories, the bacterium is often identified as part of a multicomponent panel of respiratory pathogens. [37 ]

The sample may be a nasal or throat swab, sputum, or other respiratory tract specimen. If possible, the specimen is collected before antibiotics are started, as the likelihood of detecting the bacteria by molecular methods or culture may decrease after antibacterial therapy. [38]

Diagnosis based solely on a blood test for immunoglobulin G is not recommended. This result may reflect a long-standing infection and does not prove that the current cough is related to an active infection. Serological testing sometimes requires comparing blood samples taken during the acute phase and several weeks later, and interpretation of microimmunofluorescence is technically complex and subjective. [39]

In infants, Chlamydia trachomatis testing is performed using a nasopharyngeal swab. Cell culture is considered the reference method, but direct antigen detection and nucleic acid amplification tests can be used if the laboratory has validated their suitability for nasopharyngeal specimens. The decision to initiate treatment is sometimes made before the results are available if the clinical probability is high. [40]

Method	What does it show?	Restrictions
Nucleic acid amplification test	Genetic material of bacteria	It is advisable to take it before antibiotics.
Polymerase chain reaction as part of a respiratory panel	Several pathogens at the same time	Not every panel includes chlamydia.
Cell culture	Viable bacteria	Complex and slow
Paired blood tests	Changes in antibody levels over time	Requires 2 visits
Single immunoglobulin class G	Fact of past contact	Does not prove acute infection
Chest X-ray	Presence of pneumonia	Does not identify the pathogen

Current recommendations for the selection of laboratory methods are published by the US Centers for Disease Control and Prevention. [41]

ICD-10 and ICD-11 codes

In the International Classification of Diseases, 10th revision, acquired chlamydial pneumonia is coded as J16.0 - chlamydial pneumonia. For congenital or neonatal pneumonia associated with chlamydia, P23.1 - congenital pneumonia due to chlamydia - is used. Ornithosis and psittacosis are coded as A70 - infection due to Chlamydia psittaci. [42] [43]

In the International Classification of Diseases, 11th revision, coding may be clustered. For acquired pneumonia due to Chlamydia pneumoniae, CA40.0Y - pneumonia due to other specified bacteria - may be used, with an additional pathogen code of XN9EE - Chlamydia pneumoniae. Neonatal chlamydial pneumonia is included in KB24 - congenital pneumonia, and Chlamydia psittaci infections are classified in 1C22; pneumonia is specified by additional coding if necessary. [44] [45] [46]

System	Code	Formulation
ICD 10	J16.0	Chlamydial pneumonia
ICD 10	P23.1	Congenital pneumonia caused by chlamydia
ICD 10	A70	Chlamydia psittaci infection
ICD 11	CA40.0Y	Pneumonia due to other specified bacteria
ICD 11	XN9EE	Chlamydia pneumoniae as a clarifying code for the pathogen
ICD 11	KB24	Congenital pneumonia, including neonatal chlamydial pneumonia
ICD 11	1C22	Chlamydia psittaci infections

The code is selected based on the confirmed pathogen, the patient's age, and the form of the disease; in the International Classification of Diseases, 11th revision, a combination of the primary and secondary codes may be required. [47]

Treatment of Chlamydia pneumoniae infection in adults and children

Most mild Chlamydia pneumoniae infections resolve on their own, and not every patient requires antibiotics. Treatment decisions are made by a physician based on the severity of symptoms, the presence of pneumonia, age, comorbidities, and risk of complications. Antibiotics should not be prescribed solely because of a positive antibody test. [48]

If antibacterial therapy is necessary, the US Centers for Disease Control and Prevention classifies macrolides, primarily azithromycin, as first-line drugs. Doxycycline and other tetracyclines are also active, as are respiratory fluoroquinolones in certain clinical situations. [49]

The specific regimen depends not only on the suspected chlamydial infection but also on the treatment guidelines for community-acquired pneumonia. The physician must consider the likelihood of pneumococcus, Haemophilus influenzae, mycoplasma, and other pathogens, local bacterial resistance, allergies, cardiac arrhythmias, renal function, and drug interactions. [50]

Macrolides require caution in patients with prolongation of the QT interval, certain rhythm disorders, and when combined with other medications that affect cardiac electrical activity. Doxycycline has age and individual restrictions, and fluoroquinolones should not be used as a simple substitute without a risk assessment. Therefore, independent antibiotic selection is unacceptable. [51]

Cough and weakness may persist for a long time even after appropriate treatment. Persistence of a cough alone does not prove the antibiotic's effectiveness and is not an automatic indication for a repeat course. A reassessment is necessary if the condition worsens, high fever returns, shortness of breath worsens, or new changes appear on the chest X-ray. [52]

Clinical situation	General approach
Mild infection without pneumonia	Sometimes observation and symptomatic care are sufficient.
Confirmed or probable bacterial pneumonia	The antibiotic is prescribed by a doctor.
First-line drugs against Chlamydia pneumoniae	Macrolides
Possible alternative	Doxycycline or another tetracycline
Selected adult patients	A respiratory fluoroquinolone may be considered.
Long-lasting cough after therapy	Re-evaluation, not automatic re-course

General antibacterial therapy options are based on the clinical review by the US Centers for Disease Control and Prevention.[53]

Treatment of chlamydial pneumonia in infants

In an infant, treatment may be started before laboratory results are available if the age, cough pattern, radiographic findings, and maternal history create a high probability of Chlamydia trachomatis. Waiting for results should not delay care for a child with rapid breathing or other signs of pneumonia.[54]

The recommended regimen includes erythromycin at a total dose of 50 mg per kilogram of body weight per day, divided into 4 doses, for 14 days. Dosage calculation should be performed by a pediatrician, as an error in the dosage of the drug in an infant can be dangerous. [55]

An alternative is azithromycin suspension at a dose of 20 mg per kilogram of body weight once daily for 3 days. However, there is less data on the effectiveness of short-course azithromycin than on erythromycin, so post-treatment monitoring is required. [56]

Erythromycin is approximately 80% effective, so some children may require a repeat course. In infants under 6 weeks of age, erythromycin or azithromycin is associated with a risk of hypertrophic pyloric stenosis—a narrowing of the stomach outlet. Parents are cautioned to seek immediate medical attention if vomiting worsens, especially projectile vomiting. [57]

The baby's mother and her sexual partner should be examined, tested, and treated for urogenital chlamydia. Treating the infant alone does not eliminate the source of the infection or protect the mother from complications or reinfection. [58]

Question	Recommendation
Who prescribes treatment?	Pediatrician
Basic scheme	Erythromycin 14 days
Alternative scheme	Azithromycin 3 days
Are eye drops enough?	No
Is control necessary?	Yes
Is a repeat course possible?	Yes, if it is not effective enough
What to monitor in a baby under 6 weeks old	Symptoms of pyloric stenosis
Should the mother and partner be examined?	Yes

The dosage regimens are provided for informational purposes only, as recommended by the U.S. Centers for Disease Control and Prevention; do not calculate the dose for an infant yourself. [59]

What can respiratory chlamydia be confused with?

Chlamydia pneumoniae, a respiratory infection, cannot be reliably distinguished by symptoms from viral pharyngitis, influenza, coronavirus infection, mycoplasma infection, whooping cough, acute bronchitis, and other forms of community-acquired pneumonia. Even a gradual onset, hoarseness, and a lingering cough are only clues, not proof. [60]

In adults with pneumonia, pneumococci, Haemophilus influenzae, Legionella, and mixed infections must also be considered. For this reason, treatment for community-acquired pneumonia is often started empirically, that is, until the pathogen is accurately identified, choosing a regimen that covers the most likely bacteria. [61]

In an infant with a hacking cough, whooping cough, viral infections, heart defects, aspiration, gastroesophageal reflux, and other causes of rapid breathing should be excluded. Age 1-3 months and maternal chlamydia increase the likelihood of Chlamydia trachomatis, but do not negate the need to look for other conditions. [62]

If a patient experiences a high fever, severe headache, or muscle pain, the physician should determine whether the patient has been exposed to birds. Ornithosis requires a separate epidemiological investigation and may be accompanied by damage to the liver, heart, or nervous system. [63]

A diagnosis of chronic respiratory chlamydia should not be made solely based on a positive immunoglobulin G antibody test. In many people, such antibodies reflect a previous infection. Active disease is confirmed based on symptoms, molecular testing of respiratory tract material, and other objective data. [64]

Possible disease	What might it be similar to?
Viral respiratory infection	Runny nose, sore throat, cough
Flu	Fever, weakness, cough
Mycoplasma infection	Gradual onset and lingering cough
Whooping cough	Paroxysmal or hacking cough
Pneumococcal pneumonia	Fever, cough, chest pain
Legionellosis	Pneumonia and systemic symptoms
Ornithosis	Dry cough, fever, headache
Bronchial asthma	Cough, wheezing, shortness of breath

Differential diagnosis is made on the basis of the clinical picture, radiography and laboratory tests, and not on a single symptom or antibody. [65] [66]

When urgent medical care is needed

An adult needs urgent evaluation if they experience increasing shortness of breath, blue lips, confusion, severe weakness, chest pain, a drop in blood pressure, hemoptysis, or an inability to drink fluids. These signs may indicate severe pneumonia or a complication, regardless of the specific pathogen. [67]

Seek medical attention immediately if, after initial improvement, the temperature rises again, the cough intensifies, or severe shortness of breath develops. This may be due to progression of pneumonia, the addition of another infection, pleurisy, a cardiac complication, or incorrect initial therapy. [68]

In infants, warning signs include a faster-than-normal respiratory rate, retraction of the skin between or under the ribs, flaring of the nasal alae, cyanosis, episodes of respiratory arrest, refusal to feed, lethargy, and decreased urine output. A child in the first months of life with these symptoms should be examined immediately. [69]

A particularly urgent evaluation is needed for an infant with a cough and a known untreated maternal chlamydia infection during pregnancy. A subacute course without high fever should not create a false sense of security. [70]

After contact with birds, a combination of fever, severe headache, dry cough, shortness of breath, and severe weakness requires reporting the exposure to a physician. Without such information, ornithosis can easily be mistaken for other community-acquired pneumonia. [71]

Red flag	Possible meaning
Severe shortness of breath	Respiratory failure
Blue lips	Lack of oxygen
Confusion	Severe infection or hypoxia
Severe chest pain	Pneumonia, pleurisy or cardiac complication
Hemoptysis	Damage to the airways or lungs
Infant refusal to feed	Risk of dehydration and respiratory failure
Intercostal retraction in a child	Increased work of the respiratory muscles
Contact with birds and severe fever	Possible ornithosis

Any red flag requires in-person evaluation; home antibody testing and self-administered antibiotics are not a substitute for testing.[72]

Prevention and prognosis

There is no vaccine against Chlamydia pneumoniae. Antibiotics are also generally not prescribed prophylactically after routine contact with an infected person. Basic measures include hand washing, covering your mouth and nose when coughing or sneezing, regular ventilation, and reducing close contact during illness. [73]

Because people can spread the infection before symptoms appear and for several weeks after, it is difficult to completely prevent transmission in a group setting. Hygiene is especially important in schools, dormitories, healthcare facilities, and nursing homes. [74]

A previous infection does not provide reliable lifelong protection, so it is possible to become infected again. In older people, repeated infections are more likely to result in severe outcomes, making early treatment especially important if shortness of breath or signs of pneumonia are present. [75]

Prevention of chlamydial pneumonia in infants begins during pregnancy. Screening of women at risk, prompt treatment of identified Chlamydia trachomatis, monitoring of cure, and treatment of the partner significantly reduce the likelihood of infection of the child during childbirth. [76]

The prognosis for Chlamydia pneumoniae infection is generally favorable: most patients recover spontaneously or with treatment. However, cough and weakness may persist for a long time. Infants with chlamydial pneumonia require monitoring, as some children experience persistent changes in lung function tests later in life. [77]

Preventive measure	For what infection is it especially important?
Washing hands	Chlamydia pneumoniae
Covering coughs and sneezes	Chlamydia pneumoniae
Ventilation of premises	Outbreaks in groups
Refusal of prophylactic self-medication with antibiotics	All forms
Pregnancy screening	Infant pneumonia
Treatment of a pregnant woman's sexual partner	Prevention of re-infection
Careful cleaning of bird cages	Ornithosis
Use of protective equipment when working with birds	Occupational risk of ornithosis

Preventive recommendations are based on materials on Chlamydia pneumoniae, neonatal chlamydia and psittacosis.[78][79][80]

Frequently asked questions

Is respiratory chlamydia a sexually transmitted infection? Chlamydia pneumoniae is not a sexually transmitted infection: it is spread primarily through droplets from coughing and sneezing. Another species, Chlamydia trachomatis, is sexually transmitted. [81]

Can you become infected with Chlamydia pneumoniae from a sexual partner? You can become infected from anyone through close respiratory contact if they cough or sneeze and release the bacteria. Sexual intercourse is not a factor in this. [82]

How long does it take for symptoms to appear? With Chlamydia pneumoniae infection, symptoms usually appear 3-4 weeks after infection. With ornithosis, they often appear 5-14 days after contact with birds. [83] [84]

Does pneumonia always develop? No. Most infections are asymptomatic or mild, such as pharyngitis, laryngitis, sinusitis, or bronchitis. Pneumonia develops in only a fraction of patients. [85]

What is the most characteristic symptom? A cough that slowly worsens and persists for a long time is often noted, often accompanied by a sore throat and hoarseness. However, this combination of symptoms does not allow for a confirmed diagnosis without laboratory testing. [86]

Which test is considered the most accurate for acute infection? A nucleic acid amplification test, including polymerase chain reaction, performed on respiratory tract specimens is preferred. [87]

Can IgG be used to make a diagnosis? No. A single IgG result may indicate a previous infection and does not confirm that the current cough is caused by active Chlamydia pneumoniae. [88]

Is it necessary to take antibiotics? No. Many mild infections resolve on their own. Antibiotics are more often prescribed for pneumonia, severe infections, or other clinical indications after a doctor's evaluation. [89]

What is the typical treatment for Chlamydia pneumoniae? The U.S. Centers for Disease Control and Prevention recommends macrolides, including azithromycin, as first-line medications; tetracyclines and fluoroquinolones are also possible. The specific drug chosen is based on age, underlying medical conditions, and the type of pneumonia. [90]

Why doesn't my cough go away immediately after taking an antibiotic? With this infection, cough and malaise can persist for weeks or months even after adequate treatment. A repeat antibiotic is not automatically necessary, but only after a re-evaluation. [91]

How does chlamydial pneumonia present in an infant? Typical symptoms include age 1-3 months, intermittent, repetitive cough, rapid breathing, no significant fever, hyperinflation of the lungs, and bilateral changes on a chest radiograph. [92]

Is infant pneumonia related to maternal urogenital chlamydia? Yes. The baby usually acquires Chlamydia trachomatis during birth through contact with the mother's infected cervix.[93]

Can eye ointment be used to protect a baby after birth? Standard ophthalmic prophylaxis with erythromycin does not prevent chlamydial conjunctivitis or pneumonia. The primary prevention is detection and treatment of chlamydia in pregnant women before delivery. [94]

What is ornithosis? It is a Chlamydia psittaci infection that is most commonly contracted by humans by inhaling dust from the dried secretions or droppings of infected birds.[95]

Should a sexual partner be tested for Chlamydia pneumoniae? No, not if it's the respiratory Chlamydia pneumoniae. A sexual partner should be tested if urogenital Chlamydia trachomatis is detected or if a chlamydial infection occurs in a newborn. [96] [97]

Key points from experts

Margaret R. Hammerschlag, MD, professor of pediatrics and medicine at the State University of New York, an expert in pediatric infectious diseases and chlamydial infections, emphasizes in her work that Chlamydia pneumoniae is a distinct respiratory pathogen, distinct from the sexually transmitted Chlamydia trachomatis. The practical implication is that respiratory antibodies should not be interpreted as evidence of urogenital chlamydia. [98] [99]

Joshua P. Metley, MD, PhD, chief of the Division of General Internal Medicine at Massachusetts General Hospital and lead author of the American Thoracic Society and Infectious Diseases Society of America guidelines on community-acquired pneumonia, points out that treatment choices for pneumonia should consider the full range of likely pathogens and patient characteristics. The practical takeaway: suspected chlamydia should not lead to narrow self-medication with a single antibiotic without assessing the severity and alternative causes. [100] [101]

Kimberly A. Workowski, MD, professor of infectious diseases at Emory University and lead author of the Centers for Disease Control and Prevention's sexually transmitted infection guidelines, emphasizes the characteristic clinical presentation of Chlamydia trachomatis pneumonia in infants and the need to evaluate the mother and her partner. The practical lesson: treatment of the infant should be accompanied by elimination of the maternal source of infection. [102] [103]

Margaret R. Hammerschlag also served as an expert consultant to the U.S. Centers for Disease Control and Prevention on sexually transmitted infection guidelines and established a chlamydia research laboratory. Her work demonstrates why chlamydial pneumonia in infants requires a separate approach and should not be confused with Chlamydia pneumoniae infection in schoolchildren and adults. [104]

The US Centers for Disease Control and Prevention's Chlamydia pneumoniae Expert Panel emphasizes that molecular methods are the preferred method for diagnosing acute infection, and a single IgG titer should not be used for diagnosis. The practical implication is that the popular practice of antibody-based treatment is not consistent with current laboratory guidelines. [105]

Conclusion

The term "respiratory chlamydia" encompasses several different infections. In schoolchildren and adults, the disease is most often associated with Chlamydia pneumoniae, which is transmitted by coughing and sneezing. In infants, pneumonia can be caused by Chlamydia trachomatis, acquired during birth, and Chlamydia psittaci should be considered after contact with birds.[106] [107] [108]

The most reliable method for confirming acute Chlamydia pneumoniae infection is molecular testing of respiratory tract material. A single positive immunoglobulin G result does not confirm active disease and is not sufficient grounds for antibiotic therapy. [109]

Most infections are mild, but pneumonia, severe shortness of breath, deteriorating condition in an elderly person, or any respiratory symptoms in an infant in the first months of life require a medical evaluation. Treatment depends on the specific pathogen, age, and severity of the disease, so there is no universal treatment for respiratory chlamydia. [110]