Corneal opacity is the fifth leading cause of blindness globally [1]. Infectious keratitis (IK) is a major contributor of corneal blindness, causing an estimated 1.5–2.0 million new cases of monocular blindness annually [[2], [3], [4], [5]]. According to WHO, approximately 6 million people suffer moderate-to-severe vision impairment from corneal scarring, much of which is attributable to prior infections caused by bacterial, fungal, viral, or parasitic organisms [6,7]. Bacterial keratitis (BK) is the most common form of IK and patients typically present with pain, redness, and corneal ulceration, and can rapidly cause vision loss if not promptly treated [8].

The epidemiology of BK varies by geography and local risk factors. Major risk factors include contact lens wear, ocular trauma (especially vegetative injury), ocular surface disease (such as dry eye, blepharitis), eyelid malposition, and prior surgery [8,9]. In developed countries, contact lens–related BK (often caused by Pseudomonas spp.) the most common underlying risk factor, whereas in tropical or agricultural settings, trauma-related infections (caused by Gram-positive bacteria like Streptococci and Staphylococci) predominate. Gram-positive bacteria are more frequently recovered in BK isolates in temperate regions, while Gram-negative bacteria (and fungi) are relatively more common in tropical climates. Despite these known patterns, global data on BK burden are fragmented. Prompt antibiotic treatment can often limit the loss of vision caused by BK, but rising antimicrobial resistance in ocular isolates is a cause of increasing concern. Globally, there is an increase in the reporting of methicillin-resistant S. aureus (MRSA) and fluoroquinolone-non-susceptible Staphylococcus or Pseudomonas, limiting the current therapies for effectively treating BK [[10], [11], [12], [13], [14]]. Existing reports of ocular isolates suggest evolving resistance; however, the evidence is limited to single-center or regional distribution of cases. Thus, the global burden of BK and the current antibiotic susceptibility patterns across the world remain unclear.

This systematic review and meta-analysis were performed to assess the global patterns of incidence, risk factors and susceptibility in BK patients. Our objectives were to estimate the pooled proportion of infectious keratitis cases due to bacteria, map geographic variations, identify the risk factors causing BK and predominant causative bacteria, and summarize their antibiotic susceptibility patterns. The findings will inform clinicians and public health authorities about the global impact of BK and guide empirical therapy decisions.