A 38-year-old contact lens wearer from Delhi presents with acute corneal ulcer, severe pain, and profuse purulent discharge. Culture grows Pseudomonas aeruginosa. Regarding bacterial corneal ulcers and their management, all of the following are appropriate EXCEPT:

Explanation

## Bacterial Corneal Ulcer — Treatment & Organism Spectrum **Key Point:** Pseudomonas aeruginosa keratitis is a **sight-threatening emergency** that requires **aggressive, combination topical antibiotic therapy**, not monotherapy. Fluoroquinolone monotherapy is inadequate and risks treatment failure and perforation. ### Treatment Hierarchy for Bacterial Keratitis | Severity | Recommended Regimen | Rationale | |----------|---------------------|----------| | **Mild–moderate (non-Pseudomonas)** | Topical fluoroquinolone monotherapy (moxifloxacin, gatifloxacin) | Good corneal penetration, broad spectrum | | **Severe or Pseudomonas** | **Fortified antibiotics**: Cefazolin 5% + Tobramycin 1.4% (or Gentamicin 1.4%) | Higher drug concentration, synergistic activity | | **Suspected perforation / descemetocele** | Add systemic antibiotics (fluoroquinolone or cephalosporin) | Systemic coverage for anterior chamber seeding | **High-Yield:** Pseudomonas is **aggressive and mucoid**; it produces proteases and biofilm, making it resistant to single-agent therapy. Fortified topical antibiotics are the standard of care. ### Organism Spectrum in Contact Lens Keratitis **Mnemonic: GNACC** — Gram-negative organisms dominate contact lens-associated keratitis: - **G**ram-negative (Pseudomonas, Serratia, Proteus, Moraxella) - **N**eisseria - **A**cid-fast bacilli (rare) - **C**occi (Staphylococcus, Streptococcus — less common in CL wearers) - **C**andida (fungal, rare in CL keratitis) **Clinical Pearl:** Contact lens overwear, poor hygiene, and contaminated lens solutions are the major risk factors. Pseudomonas thrives in moist environments (lens cases, solution bottles). ### Sequelae of Severe Bacterial Keratitis - **Corneal scarring** (opacity, reduced vision) - **Neovascularization** (pannus formation) - **Corneal thinning / ectasia** - **Anterior synechiae** (if iritis develops) - **Perforation** (if untreated) **Warning:** Topical corticosteroids should be **avoided in the acute phase** of bacterial keratitis; they increase the risk of perforation and dissemination. They may be cautiously introduced only after 48–72 hours of antibiotic therapy and clinical improvement. ### Why Option 0 Is Incorrect Fluoroquinolone monotherapy is **inadequate for Pseudomonas keratitis**. Although fluoroquinolones have good corneal penetration, Pseudomonas is virulent and requires **fortified topical combination therapy** (cephalosporin + aminoglycoside) applied frequently (every 1–2 hours initially) to achieve therapeutic corneal concentrations and prevent perforation.