Bacterial conjunctivitis

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Bacterial conjunctivitis includes neisserial conjunctivitis (hyperacute bacterial conjunctivitis), acute bacterial conjunctivitis, and chlamydial conjunctivitis (including trachoma and inclusion conjunctivitis), and it can be an ocular emergency. Factors that can help differentiate between the subtypes include severity and onset of symptoms, patient history, and associated systemic features (e.g., genitourinary symptoms). All patients with neisserial conjunctivitis, inclusion conjunctivitis, and acute bacterial conjunctivitis with severe symptoms or risk factors for severe infection (e.g., contact lens use, immunodeficiency) should undergo diagnostic studies, including a conjunctival culture. For patients with mild acute bacterial conjunctivitis or trachoma, the diagnosis may be made clinically. Antibiotic therapy is recommended for all types of bacterial conjunctivitis. Patients with neisserial or chlamydial conjunctivitis, and any patients with red flags for conjunctivitis, should be referred to ophthalmology. Undertreated or long-term infections can compromise the layers of the eye (e.g., cornea) and lead to the formation of scars and ulcers, ultimately causing blindness.

• Most common form of conjunctivitis in children ^[2]
• Most common in winter ^[2]

Epidemiological data refers to the US, unless otherwise specified.

• Clinical features of conjunctivitis are similar for bacterial, viral, and noninfectious forms. ^[3]
• Compared to viral and noninfectious conjunctivitis, bacterial conjunctivitis is more commonly associated with: ^[2][4]
  • Purulent or mucopurulent discharge, which may be severe enough to adhere the eyelashes together
  • Absence of itching
• Rapid onset and severe symptoms suggest neisserial conjunctivitis.
• Patients with gonococcal conjunctivitis or inclusion conjunctivitis may present with systemic features, e.g., genitourinary discharge.

Indications ^[5]

• Suspected neisserial conjunctivitis
• Suspected inclusion conjunctivitis
• Acute bacterial conjunctivitis in combination with:
  • Severe conjunctivitis
  • Contact lens use
  • Refractory or recurrent symptoms
  • Immunodeficiency
• Diagnostic uncertainty

Patients with mild bacterial conjunctivitis or trachoma can be diagnosed clinically.

Laboratory studies ^[5]

• Culture of conjunctiva and exudate with Gram stain and Giemsa stain ^[5][6]
• Consider the following, depending on the suspected pathogen:
  • PCR
  • Direct fluorescent antibody test ^[6]
  • Enzyme immunoassay

Acute bacterial conjunctivitis is a common presentation in primary care; common pathogens include Streptococcus pneumoniae and Haemophilus influenzae in children and Staphylococcus aureus in adults. Neisserial conjunctivitis and chlamydial conjunctivitis manifest differently and require specialized management; these infections are covered separately in their respective sections.

Etiology ^[7]

• Most common in adults: S. aureus
• Most common in children: S. pneumoniae and H. influenzae
• Others, e.g., Pseudomonas spp., Moraxella catarrhalis ^[8]

Contact lens wearers are at increased risk of serious infections with gram-negative bacteria such as Pseudomonas aeruginosa. ^[8]

Clinical features ^[5]

• Unilateral or bilateral symptoms of conjunctivitis, including:
  • Conjunctival injection
  • Mucopurulent discharge
• Symptoms typically last 7–10 days but may last up to 4 weeks. ^[7]
• Significant pain or vision changes are not usually present and are red flags in conjunctivitis.

Diagnostics ^[5][7]

• Primarily a clinical diagnosis
• Obtain conjunctival culture with Gram stain and Giemsa stain in patients with any of the following: ^[5][7]
  • Severe conjunctivitis
  • Contact lens use
  • Recurrent or refractory symptoms
  • Immunodeficiency
  • Possible gonorrheal or chlamydial conjunctivitis
• Further studies such as PCR may be considered as needed.

Treatment ^[5]

• Advise patients to immediately remove their contact lenses.
  • Avoid wearing for ≥ 2 weeks. ^[9]
  • Discard disposable contact lenses and contact lens storage cases. ^[8]
• Provide supportive therapy for conjunctivitis.
• Consider a 5–7 day course of topical broad-spectrum antibiotics. ^[5]
• Refer patients with the following to ophthalmology:
  • Suspected MRSA infection
  • Red flags in conjunctivitis (including contact lens use)
  • Symptoms that persist after > 1 week of treatment
• Educate patients on prevention of infectious conjunctivitis.

Topical antibiotic therapy

• Indicated for patients who: ^[2]
  • Wear contact lenses
  • Have mucopurulent discharge and eye pain
  • Have known ocular surface disease
• Use in all other patients may help speed up recovery. ^[10]
• Commonly used classes of antibiotics in children and adults include : ^[2][5][10]
  • Macrolides, e.g., erythromycin or azithromycin ^[2]
  • Combination drops, e.g., polymyxin B/trimethoprim ^[2]
  • Fluoroquinolones, e.g., ciprofloxacin (use if gram-negative pathogens are suspected, e.g., in contact lens wearers) ^[9]
  • Sulfonamides, e.g., sulfacetamide ^[2]
  • Aminoglycosides, e.g., tobramycin ^[2]
• For antibiotic treatment in newborns, see “Antimicrobial therapy for neonatal conjunctivitis.”

Most cases of bacterial conjunctivitis are self-limited; however, the use of topical antibiotics speeds up recovery and may reduce the risk of transmission. ^[5]

Complications

• Conjunctivitis-otitis syndrome ^[11]
• Keratitis ^[8]
• Anterior uveitis ^[8]
• Preseptal cellulitis ^[5]
• Chronic bacterial conjunctivitis (symptoms lasting > 4 weeks) ^[2]

Neisserial conjunctivitis, or hyperacute bacterial conjunctivitis, is a severe type of infectious conjunctivitis most commonly caused by Neisseria gonorrhoeae and characterized by an abrupt onset of quickly worsening symptoms (i.e., profuse purulent discharge, pain, and vision changes). ^[2][5]

Etiology ^[5]

• Most commonly: infection with N. gonorrhoeae (gonococcal conjunctivitis)
  • Sexually active adults: direct contact with contaminated secretions (e.g., from the genitalia to the hand to the eye)
  • Neonates: perinatal transmission (see “Neonatal gonococcal conjunctivitis”)
• Rarely: infection with Neisseria meningitidis (primary meningococcal conjunctivitis)

Consider sexual abuse in children presenting with gonorrheal conjunctivitis. ^[5]

Neonatal gonococcal conjunctivitis is rare in the US because of prophylaxis at birth with erythromycin ophthalmic ointment. ^[12]

Clinical features ^[5][7]

• Hyperacute conjunctivitis
  • Marked eye swelling
  • Profuse purulent discharge
  • Severe eye pain ^[7]
  • See also “Clinical features of conjunctivitis.”
• Preauricular lymphadenopathy
• Corneal lesions and/or ulceration
• Possibly symptoms of genitourinary gonorrhea or disseminated gonococcal infection

Diagnostics ^[5]

• Initiate management without waiting for diagnostic confirmation.
• All patients require confirmatory studies, e.g.: ^[5][13]
  • Gram stain: intracellular gram-negative diplococci
  • Culture
  • PCR

Rule out N. meningitidis in patients with suspected N. gonorrhoeae infection. ^[5]

Treatment ^[5][14]

• Start immediate systemic antibiotic treatment.
• Consider adding topical antibiotic therapy (e.g., if keratitis is suspected).
• Consult ophthalmology and infectious diseases early.
• For symptom relief:
  • Irrigate the affected eye(s) with saline.
  • Provide supportive therapy for conjunctivitis as needed (e.g., for pain management).
• Educate patients on preventive measures against infectious conjunctivitis.

N. gonorrhoeae infection is an ocular emergency that can lead to keratitis, perforation, and blindness without prompt treatment guided by a specialist (e.g., ophthalmology, infectious diseases). ^[2][14]

Systemic antibiotic therapy

• Gonococcal conjunctivitis ; ^[5][14]
  • IM/IV ceftriaxone (off-label) ^[5][14]
  • Consider addition of azithromycin; (off-label) or doxycycline (off-label). ^[5]
  • For prevention and treatment in infants, see “Neonatal gonococcal conjunctivitis.”
  • Trace partners and provide treatment for gonorrhea.
• Primary meningococcal conjunctivitis
  • Urgently consult infectious diseases to determine antibiotic therapy.
  • Patients are usually managed with third-generation cephalosporins (for dosages, see “Pathogen-specific therapy in meningitis”). ^[15]
  • Consider prophylactic treatment for contacts (see “Postexposure chemoprophylaxis for bacterial meningitis”). ^[15][16]

Do not delay antibiotics for diagnostic studies if neisserial conjunctivitis is clinically suspected. ^[5]

Depending on the Chlamydia serotype, chlamydial conjunctivitis can manifest as inclusion conjunctivitis or trachoma. ^[17]

Inclusion conjunctivitis is a form of bacterial conjunctivitis caused by infection with C. trachomatis serotypes D–K, which normally cause genitourinary chlamydia.

Etiology ^[5]

• Infection with C. trachomatis serotypes D–K.
• Transmission can be: ^[18]
  • Sexual: spread to the eyes from a preexisting genital infection (from the genitalia to the hand to the eye)
  • Perinatal (see “Neonatal chlamydial conjunctivitis”)
  • Via contaminated, unchlorinated swimming pools (rare)

Consider sexual abuse in children presenting with inclusion conjunctivitis. ^[5]

Clinical features ^[2][5]

• May affect one or both eyes for several weeks and can include:
  • Mucopurulent discharge
  • Conjunctival follicles
  • Papillary hypertrophy
  • Preauricular lymphadenopathy
  • See also “Clinical features of conjunctivitis.”
• Patients may also have symptoms of genitourinary chlamydia infection.

Diagnostics ^[5][7]

• Can be diagnosed clinically in patients with a characteristic history and confirmed genitourinary chlamydia infection
• To confirm inclusion conjunctivitis, use one of the following tests:
  • Culture of the conjunctiva and exudate ^[5][6]
  • Direct fluorescent antibody test ^[6]
  • Enzyme immunoassay
  • PCR from scrapings of the conjunctiva ^[5][6]

Patients with suspected or confirmed chlamydia conjunctivitis should also undergo diagnostic studies for gonorrhea. ^[2]

Treatment ^[2][5]

• Start systemic antibiotics. ^[2][5]
  • Adults: azithromycin (off-label) OR doxycycline (off-label) ^[2][5]
  • Neonates: See “Treatment of neonatal conjunctivitis.”
• Provide supportive therapy for conjunctivitis.
• Assess for and treat concurrent infections in patients and their partners. ^[2]
  • Genitourinary chlamydia infection
  • Gonorrhea
• Educate patients on preventive measures against infectious conjunctivitis.

Antibiotics should not be delayed for diagnostics if inclusion conjunctivitis is clinically suspected. ^[5]

Trachoma is a form of bacterial conjunctivitis seen in resource-limited settings. Repeated infection with C. trachomatis serotypes A–C leads to conjunctival scarring and blindness.

Etiology ^[5][17][19]

• Infection with C. trachomatis serotypes A–C; transmission is either:
  • Direct (human-to-human contact via eyes or nose)
  • Indirect (e.g., shared towels, eye-seeking flies) ^[17]
• Incubation period: 5–12 days

Epidemiology ^[5][17]

• The most common infectious cause of blindness worldwide ^[2][19][20]
• Africa is the most affected continent. ^[17]
• Predominantly affects young children and women ^[17]
• Transmission is more common in households with: ^[17]
  • Inadequate access to water and sanitation
  • Crowding

C. trachomatis serotypes A, B, and C are most common in Africa and can cause Blindness and Chronic inflammation.

Clinical features ^[17][19]

Infection can be recurrent or chronic; ; active and cicatricial phases may occur simultaneously.

• Active phase: active trachoma inflammation
  • Mucopurulent discharge
  • Papillary reaction
  • Conjunctival follicles (with involution leading to Herbert pits if untreated)
  • Inflamed upper tarsal conjunctiva
  • See also “Clinical features of conjunctivitis.”
• Cicatricial phase: develops if the active phase is severe and prolonged
  • Chronic/recurrent inflammation in both eyes → conjunctival scarring and progressive conjunctival shrinkage
  • Can lead to corneal ulcers and opacities, superficial neovascularization with cellular infiltration (corneal pannus), entropion, and/or trichiasis

Chronic untreated infection can lead to blindness. ^[2]

Diagnostics ^[5]

• Diagnosis is primarily clinical, but early trachoma manifests with limited signs and symptoms and may therefore be missed.
• Confirmatory testing is rarely performed, but options include : ^[21]
  • NAAT
  • Microscopy and culture
  • Direct fluorescent antibody test
  • Enzyme immunoassay

Because of the difficulties in accurately diagnosing trachoma, mass drug administration is recommended in areas with a high prevalence (> 10% in children). ^[19]Laboratory studies are of limited use in trachoma because they can only confirm current infection with C. trachomatis. ^[21]

Treatment ^[2]

• Active phase
  • Antibiotic therapy
    • Preferred: single dose of oral azithromycin (off-label) ^[22][23]
    • Alternatives (off-label), e.g.: tetracycline or erythromycin (topical or systemic) ^[2][22][23]
  • Supportive treatment for conjunctivitis
  • Patient education on prevention of trachoma
• Cicatricial phase: Refer to ophthalmology for consideration of surgery. ^[23][24]
  • Recommended surgery for trichiasis: tarsal rotation ^[17][19]
  • While awaiting surgery, recommend taping eyelashes to the eyelid. ^[23]

Prevention of trachoma ^[17]

• Educate patients on preventive measures (see also “Prevention of infectious conjunctivitis”). ^[25]
  • Advise patients to wash their face regularly.
  • Promptly seek treatment for infections.
  • Avoid sharing towels.
• Public health measures to prevent new infections include: ^[17][26]
  • Mass drug administration in high-prevalence areas
  • Improved access to safe water
  • Improved sanitation (e.g., building latrines, insecticide against flies)

Trachoma is a public health issue in many resource-limited countries. The WHO has introduced the SAFE strategy for trachoma treatment and elimination: Surgery, Antibiotics, Facial cleanliness, Environmental improvement. ^[17]