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Age factor in the fluoroquinolone susceptibility of gram-positive cocci isolates from bacterial keratitis cases
Koji Ueda1,2, Takuya Iwasaki1, Takashi Ono3,4
1Miyata Eye Hospital, Kurahara 6-3, Miyakonojo, Miyazaki, 885-0051, Japan.
Purpose:
To determine the relationship between fluoroquinolone susceptibility of gram-positive cocci (GPC) isolated from patients with bacterial keratitis and the age of the patients or the date of onset.
Methods:
Bacterial isolates were obtained from corneal lesions of patients with infectious keratitis treated between January 2008 and December 2016. The fluoroquinolone susceptibility of GPC was assessed, and a retrospective review of microbiological records was performed. Fluoroquinolone susceptibility was measured through broth microdilution in accordance with protocols of the Clinical and Laboratory Standards Institute. Statistical analysis was performed using a generalized estimating equation and cubic spline to determine the association between fluoroquinolone susceptibility of GPC isolated from corneal lesions and patient age.
Results:
Of the 1200 bacterial isolates, 471 GPC were identified. They included Staphylococcus epidermidis (45.6%), other coagulase-negative Staphylococcus sp. (17.8%), and Staphylococcus aureus (18.3%). Levofloxacin susceptibility of GPC exhibited a negative relationship with age and had an odds ratio of 0.893 (95% confidence interval, 0.825-0.967) for every 10 years of age. A non-adjusted cubic spline curve was well correlated with year-adjusted data in a generalized additive model, and the levofloxacin susceptibility of GPC was initially stable but gradually declined after 40 years of age, before re-stabilizing again after 70 years of age.
Conclusion:
The fluoroquinolone susceptibility of GPC isolated from corneal lesions of infectious keratitis is high in children under 15 years of age and declines with an increase in age of patients using a generalized estimating equation and cubic spline.
Insights
Fluoroquinolone susceptibility of gram-positive cocci in bacterial keratitis is high in children but declines with age. This trend suggests age-related changes in bacterial resistance patterns for infectious keratitis treatment.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Bacterial keratitis is a serious eye infection that can lead to vision loss.
- Gram-positive cocci (GPC) are common causative agents of bacterial keratitis.
- Fluoroquinolones are a class of antibiotics frequently used to treat bacterial keratitis.
Purpose of the Study:
- To investigate the relationship between fluoroquinolone susceptibility of GPC and patient age.
- To analyze trends in fluoroquinolone resistance in GPC over time in relation to patient demographics.
Main Methods:
- Retrospective analysis of bacterial isolates from corneal lesions of infectious keratitis patients (2008-2016).
- Broth microdilution method used to determine fluoroquinolone susceptibility of GPC.
- Statistical analysis including generalized estimating equations and cubic spline modeling.
Main Results:
- Of 1200 isolates, 471 were GPC, predominantly Staphylococcus species.
- Levofloxacin susceptibility of GPC showed a negative correlation with patient age (OR 0.893 per 10 years).
- Susceptibility declined after age 40 and stabilized after age 70.
Conclusions:
- Fluoroquinolone susceptibility of GPC in bacterial keratitis is high in individuals under 15 years old.
- Age is a significant factor influencing fluoroquinolone susceptibility in GPC.
- Findings highlight the need for age-specific considerations in treating bacterial keratitis with fluoroquinolones.
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