Ocular infections, 14 infections (ocular scraping, ocular secretion DNA - qualitative)
3 days Ocular infections can lead to serious complications and vision loss if not promptly diagnosed and treated. PCR testing for ocular infections enables the rapid and accurate detection of viral, bacterial, and fungal pathogens that may affect various eye structures. This test kit is designed to identify pathogens responsible for severe ocular infections and is a valuable tool in guiding appropriate treatment.
Clinical indications for administering the test from ocular samples:
The qPCR test is recommended in the following clinical situations:
- Infectious keratitis – suspected in patients with eye pain, photophobia, corneal swelling, and blurred vision. Relevant pathogens include:
- Acanthamoeba spp. – frequently associated with contact lens use.
- Herpes Simplex Virus 1 and Varicella-Zoster Virus – viral agents responsible for herpetic keratitis.
- Bacterial and viral conjunctivitis – inflammation of the conjunctiva caused by bacteria or viruses requiring specific treatment. Detectable pathogens include:
- Chlamydia trachomatis – a common cause of neonatal conjunctivitis and trachoma.
- Human Adenovirus – the primary cause of viral conjunctivitis (“pink eye”).
- Streptococcus pneumoniae și Pseudomonas aeruginosa – bacteria linked to severe infections, particularly in immunocompromised patients.
- Uveitis – inflammation of the uveal tract associated with specific pathogens, such as:
- Toxoplasma gondii, in ocular toxoplasmosis,
- Human Cytomegalovirus (HCMV), linked to uveitis in immunocompromised individualsă.
- Fungal ocular infections – commonly associated with ocular trauma or contaminated contact lens use. This test can detect:
- Fusarium spp., a cause of fungal keratitis,
- Candida spp., potentially involved in endophthalmitis.
- Systemic viral infections with ocular manifestations – viruses such as Epstein-Barr and Herpes Simplex Virus 2 can affect eye structures, particularly in immunocompromised patients, and require immediate medical attention.
Advantages of PCR testing:
- Rapid diagnosis – quickly identifies pathogens, including viral and fungal agents, reducing time to treatment
- High sensitivity – detects even minimal amounts of pathogen genetic material, especially useful in chronic or severe ocular infections
- Multiplex capability – enables simultaneous detection of multiple bacteria, viruses, and fungi from a single sample, aiding precise diagnosis and targeted therapy
Risk factors for ocular infections:
Certain conditions or behaviors may increase the risk of ocular infections, including:
- Contact lens use – contaminated or improperly used lenses are often associated with infections, particularly those caused by Acanthamoeba and Pseudomonas aeruginosa. Patients should be educated on proper hygiene and lens care.
- Ocular trauma – injuries from accidents or surgeries may allow pathogens to enter the eye, leading to keratitis, endophthalmitis, or other severe infections. Fusarium spp. and Candida spp. are frequently implicated in post-traumatic infections.
- Immunosuppression – individuals with HIV/AIDS or those undergoing corticosteroid or chemotherapy treatments are more susceptible to ocular infections, especially from opportunistic pathogens such as HCMV, Candida spp., or Herpes Simplex Virus.
- Diabetes mellitus – diabetic patients are at greater risk for severe infections like bacterial conjunctivitis and keratitis due to microvascular changes and reduced immune function. Bacterial and fungal infections can be particularly severe in this group.
Chronic and complicated ocular infections:
Some infections can persist and develop into chronic conditions, especially in the absence of proper treatment or timely pathogen identification:
- Chronic conjunctivitis – recurrent conjunctival infections may result from resistant bacteria or persistent viral agents. Chlamydia trachomatis is one such pathogen that can lead to trachoma over time, a major cause of blindness.
- Endophthalmitis – severe intraocular infections, typically post-surgical or post-traumatic, that require immediate intervention. These can be caused by bacteria, fungi, or even viruses, and PCR-based diagnostics can reduce the risk of vision loss.
- Fungal keratitis – a rare but serious infection, often due to Fusarium spp. or Candida spp., which can lead to permanent corneal damage. Specific antifungal treatment is required, and rapid molecular diagnosis is essential.
Interpretation of results:
Positive result – indicates the presence of genetic material from a pathogen in the ocular sample, suggesting an active or recent infection. Important considerations include:
- Accurate pathogen identification – PCR detects specific DNA/RNA sequences of pathogens, so a positive result for a bacterium, virus, or fungus clearly indicates involvement in the ocular infection.
Negative result – suggests that no DNA/RNA sequences from the tested pathogens were detected in the sample. This could mean:
- The infection is caused by other pathogens not included in the test panel
- Detection window limitations – the infection may be in an early or late stage, or prior treatment (e.g., antibiotics or antivirals) may have reduced pathogen load below detectable levels
Administration of this PCR test is recommended for patients with ocular infection symptoms that do not respond to standard treatment, as well as those with risk factors, such as immunocompromised status, a history of trauma, or recent ocular surgery. Accurate and rapid pathogen identification can prevent complications and guide appropriate treatment to preserve visual integrity.
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