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Establishing a Porcine Ex Vivo Cornea Model for Studying Drug Treatments against Bacterial Keratitis
Published on: May 12, 2020
[Etiological analysis of infectious keratitis in children from 2007 to 2016]
1Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Institute of Ophthalmology, Beijing Key Laboratory of Ophthalmology & Visual Sciences, Beijing 100730, China.
Insights
Bacteria are the primary cause of infectious keratitis in children, with Streptococcus pneumoniae prevalent in younger children and Staphylococcus epidermidis in older ones. Fungal infections are less common.
Area of Science:
- Ophthalmology
- Microbiology
- Pediatrics
Background:
- Infectious keratitis in children poses a significant threat to vision.
- Understanding the etiological agents and their resistance patterns is crucial for effective treatment.
Purpose of the Study:
- To analyze the changing etiological landscape of infectious keratitis in pediatric patients.
- To identify the predominant pathogens and their antimicrobial susceptibility.
Main Methods:
- A retrospective study analyzed data from 649 children diagnosed with bacterial, fungal, or amoebic keratitis between 2007 and 2016.
- Laboratory cultures and drug sensitivity tests were performed.
- Data were analyzed based on age groups and stratified by pathogen type.
Main Results:
- Bacteria were the most common cause (81.4%), with Gram-positive cocci predominating. Streptococcus pneumoniae was most frequent in children ≤7 years, while Staphylococcus epidermidis was most common in those aged 8-14.
- Fungal infections (8.7%) were mainly caused by Fusarium, Aspergillus, and Candida. Amoebic keratitis had a positive rate of 14.8%, linked to orthokeratology lenses and trauma.
- High resistance rates to certain antibiotics were observed, including 68% for methicillin-resistant Staphylococcus. Gatifloxacin showed the highest bacterial sensitivity.
Conclusions:
- Bacterial pathogens dominate pediatric infectious keratitis, with age-specific variations in species.
- Fungal keratitis is less prevalent but significant, with specific species showing varied sensitivities to antifungals.
- Identifying causative agents and their resistance profiles is essential for guiding pediatric ophthalmic infection management.
Abstract:
Objective: To analyze the etiological changes of children with infectious keratitis. Methods: Retrospective study. Data of patients diagnosed as bacterial, fungal, and amoebic keratitis from 2007 to 2016, aged no more than 14 years old, were collected in the Department of Ophthalmology, Beijing Tongren Hospital. A total of 649 samples were obtained for routine laboratory culture identification and drug sensitivity tests. There were 361 males and 278 females, aged (5.6±4.4) years. The data were analyzed according to age ≤3 years, 4 to 7 years and>7 years. The qualitative data were analyzed by the Chi-square test. Results: Among 649 samples, 140 were culture positive, and the positive rate was 21.6%. Bacteria were the main pathogens, accounting for 81.4%. The positive rate was 31.0% among bacterial samples (114/368), and the bacterial flora was mainly Gram-positive cocci, followed by Gram-negative bacilli. Streptococcus (34.2%) ranked first, followed by Staphylococcus (27.2%) and Pseudomonas (7.9%). For children no more than 7 years old, Streptococcus pneumoniae was the most common bacterial species, while Staphylococcus epidermidis was most common in those aged 8-14 years. Gram-positive cocci were sensitive to vancomycin. Most bacteria were more sensitive to fluoroquinolones and less sensitive to cephalosporins and aminoguanidine. The detection rate of methicillin-resistant Staphylococcus was 68% (17/25). Gatifloxacin had the highest sensitivity, while the difference between gatifloxacin and moxifloxacin, levofloxacin, ofloxacin were not statistically significant (χ²=0.836,0.358, 1.490; P=0.361,0.550,0.222). A total of 254 specimens were cultured for fungi, of which 22 were positive, and the positive rate was 8.7%. The isolated fungi included Fusarium (34.8%, 8/22), Aspergillus (26.1%, 6/22) and Candida (13.0%, 3/22). The positive rate of fungal culture was 9.2% (11/119) from 2007 to 2011, and 8.1% (11/135) from 2012 to 2016, no significant difference was found between two period (χ²=0.096, P=0.757). Fusarium showed a relatively high sensitivity to terbinafine, but it was not sensitive to fluconazole and itraconazole. The sensitivities of Aspergillus to terbinafine and voriconazole were high, followed by amphotericin. Candida had high sensitivities to amphotericin, fluconazole, itraconazole and voriconazole. In 27 specimens for Acanthamoeba culture, 4 specimens were positive, and the positive rate was 14.8%. Risk factors of Acanthamoeba infection included wearing orthokeratology lenses and trauma. Conclusions: Bacteria are the main pathogenic agent of infectious keratitis in children. Streptococcus pneumoniae is the most common in children aged 7 and below, and Staphylococcus epidermidis is the most common in children aged 8-14. Fungal infection was significantly lower than that of bacteria, mainly Fusarium, Aspergillus and Candida.
