J Korean Ophthalmol Soc.  2015 Oct;56(10):1479-1488. 10.3341/jkos.2015.56.10.1479.

Gram-Negative Bacterial Keratitis: A 15-Year Review of Clinical Aspects

• Cho EY
• Lee SB

• KMID: 2214405
• DOI: http://doi.org/10.3341/jkos.2015.56.10.1479

Abstract

PURPOSE
In this study we investigated pathogenic organisms, antibiotic susceptibility, and clinical characteristics of patients with Gram-negative bacterial keratitis and elucidated risk factors for poor visual outcomes.
METHODS
The authors performed a retrospective chart review of 161 eyes (169 isolates) with Gram-negative bacterial keratitis between January 1998 and December 2012 at Yeungnam University Hospital. The study was divided into 5 periods for analysis of the bacteriological profiles and in vitro antibiotic sensitivity. The epidemiological and clinical characteristics were compared according to 3 groups (Pseudomonas species, Enterobacter species, and Serratia marcescens). Additionally, logistic regression analysis was performed to determine the risk factors.
RESULTS
The prevalence of Gram-negative organisms increased from 34.7 to 73.2% between the 1st and 5th periods (p < 0.001). Pseudomonas spp. was the most commonly isolated organism (55 eyes, 32.5%) over the total period, followed by Enterobacter spp. (41 eyes, 24.3%) and Serratia marcescens (33 eyes, 19.5%). The effective antibiotics against Gram-negative bacterial pathogens isolated from culture were cefepime (94.5%), levofloxacin (93.4%), ciprofloxacin (93.0%), and amikacin (92.3%). The incidence was higher in the elderly over 60 years of age and in early adulthood patients in their 20s and 30s. The frequent predisposing factors were contact lens wearing and corneal trauma. S. marcescens had the shortest corneal epithelium healing time (p = 0.012) and the most favorable visual outcome after treatment (p = 0.004) compared with the other species. Risk factors for poor visual outcomes included a best corrected visual acuity less than 0.1 at initial evaluation (p < 0.001) and central corneal lesion (p = 0.027).
CONCLUSIONS
Gram-negative bacterial keratitis tended to increase and Pseudomonas spp. was the most common isolate. The clinical prognosis was most favorable in S. marcescens. Early diagnosis of Gram-negative bacterial keratitis and appropriate antibiotic selection including cefepime, quinolone, or amikacin are recommended.

Keyword

Enterobacter species; Gram-negative bacterial keratitis; Pseudomonas species; Serratia marcescens

MeSH Terms

Aged
Amikacin
Anti-Bacterial Agents
Causality
Ciprofloxacin
Early Diagnosis
Enterobacter
Epithelium, Corneal
Humans
Incidence
Keratitis*
Levofloxacin
Logistic Models
Prevalence
Prognosis
Pseudomonas
Retrospective Studies
Risk Factors
Serratia
Serratia marcescens
Visual Acuity
Amikacin
Anti-Bacterial Agents
Ciprofloxacin

Figure

• 

  Figure 1. Prevalence of Gram-negative bacterial isolates (n = 169) in total bacterial keratitis at Yeungnam University Hospital during a 15-year period between 1998 and 2012. Number of Gram-positive bacterial isolates (n = 152, published data) dur-ing same study period was included for the counting of total number of isolates.20 The p-value was calculated using Chi-square test to compare the distribution of the Gram-negative bacterial isolates between 2 periods. * Gram-negative bacterial isolates significantly increased between 2 periods.

Reference

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