J Korean Ophthalmol Soc.  2012 Mar;53(3):372-384.

Analysis of Inpatients with Bacterial Keratitis Over a 12-Year Period: Pathogenic Organisms and Antibiotic Resistance

• Lim SH
• Lee SB

Abstract

PURPOSE
To investigate the distribution of bacterial keratitis isolates and the shifting trends of in vitro antibiotic susceptibility of the isolates for inpatients with bacterial keratitis.
METHODS
Three hundred ninety-two bacterial isolates with 366 positive culture cases from consecutive corneal scrapes of 988 clinically diagnosed bacterial keratitis inpatients hospitalized at Yeungnam University Hospital between January 1998 and December 2009 were retrospectively reviewed. The bacteriological profiles and in vitro resistance were evaluated in the first and second six-year periods.
RESULTS
The percentage of positive cultures was 37.0% (366/988). The commonly isolated Gram-positive and Gram-negative organisms were S. epidermidis (98; 25.0%) and P. aeruginosa (41; 10.5%), respectively. The ratio of Gram-positive to Gram-negative isolates was 1.24:1. The Gram-positive isolates significantly decreased compared to the Gram-negative isolates in the last six-year period (45.3% versus 54.7%, respectively) relative to those in the first six-year period (66.1% versus 33.9%, respectively). S. epidermidis and S. aureus decreased, and E. cloacae, S. marcescens, and S. maltophilia increased in the last six-year period. The resistance of fluoroquinolone to the Gram-positive isolates, though not statistically significant, tended to increase to 34.1% from 21.5% (p=0.061), and the methicillin-resistant S. aureus tended to increase to 54.2% from 30.0% (p=0.055).
CONCLUSIONS
S. epidermidis and P. aeruginosa were the most common bacterial keratitis isolates in Gram-positive and Gram-negative isolates. The Gram-positive isolates tended to decrease, though the Gram-negative organisms tended to increase in the last six-year period compared to the first six-year period. Empirical antibiotic selection should be based on local susceptibility patterns and distribution of bacterial isolates.

Keyword

Antibiotic resistance; Bacterial keratitis; Pathogenic organisms

MeSH Terms

Cloaca
Drug Resistance, Microbial
Humans
Inpatients
Keratitis
Methicillin Resistance
Retrospective Studies

Figure

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  Figure 1 Sex and age distribution of patients with identified bacterial isolates. Between 1998 and 2009, the most prevalent age group for patients with identified bacterial isolates was the elderly group of over 60-year-old (184 eyes, 50.3%). The male-female ratio (the number of males with identified bacterial isolates divided by the number of females with identified bacterial isolates) was 1.13:1. In early adulthood (20-39 years), the male-female ratio was 0.44:1, which shows that more young women than young men are enrolled in this age-specific group.

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