Related Experiment Video
Updated: Jun 13, 2026
Intravitreal Injection and Quantitation of Infection Parameters in a Mouse Model of Bacterial Endophthalmitis
Published on: February 6, 2021
Post-operative endophthalmitis: Antibiogram & genetic relatedness between Pseudomonas aeruginosa isolates from
Gita Satpathy1, Dipika Patnayak, Jeewan Singh Titiyal
1Department of Ocular Microbiology, Dr R.P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India. gita.satpathy@gmail.com
Background & Objectives:
Though not frequently but there are reports showing phacoemulsifiers as a potent source of infection in post-operative cases of endophthalmitis. This study was carried out to find antibiogram and genetic relatedness between Pseudomonas aeruginosa isolates from a post-cataract surgery endophthalmitis outbreak (3 patients) and internal tubings of 5 phacoemulsifiers.
Methods:
In vitro antimicrobial sensitivity patterns of the 8 bacterial isolates were observed. Genetic analysis of the bacterial isolates was done using random amplification of polymorphic DNA (RAPD) assay and PCR ribotyping. The resulting DNA band patterns were examined visually and by computer assisted analysis using unweighted pair group method.
Results:
The three P. aeruginosa patient isolates were found to be different from the five phacoemulsifier isolates in sensitivity towards 3 antibiotics and by genetic analysis (33 and 44% homology by RAPD assay and PCR ribotyping). Two of the patient isolates shared 100 per cent genetic homology by RAPD assay and another pair shared 100 per cent homology by PCR ribotyping. The five isolates from phacoemulsifiers did not share significant genetic homology. There was significant genetic variation between bacterial isolates from patients and phaco emulsifiers.
Interpretation & Conclusion:
Though the three P. aeruginosa isolates obtained from the patients were phenotypically similar and genetically close, they differed from the phaco-machine isolates both genetically, and in their antibiogram profile. However, the five phacoemulsifier isolates were genetically diverse though they shared the same antibiogram profile. Therefore the Ringer's lactate from phacomachines could not be conclusively proven to be the source of infection.
Insights
Pseudomonas aeruginosa from cataract surgery endophthalmitis patients showed genetic differences from phacoemulsifier isolates. This suggests phacoemulsifiers may not be the definitive source of infection, despite shared antibiotic resistance.
Area of Science:
- Ophthalmology
- Infectious Diseases
- Microbiology
Background:
- Phacoemulsifiers, used in cataract surgery, have been implicated as potential sources of post-operative endophthalmitis infections.
- Investigating the link between bacterial isolates from endophthalmitis cases and surgical equipment is crucial for patient safety.
Purpose of the Study:
- To determine the antibiogram and genetic relatedness of Pseudomonas aeruginosa isolates from post-cataract surgery endophthalmitis patients and phacoemulsifier internal tubings.
- To assess the potential role of phacoemulsifiers as a source of infection in endophthalmitis outbreaks.
Main Methods:
- In vitro antimicrobial susceptibility testing of bacterial isolates.
- Genetic analysis using random amplification of polymorphic DNA (RAPD) assay and PCR ribotyping.
- Comparative analysis of DNA band patterns using visual and computer-assisted methods.
Main Results:
- Pseudomonas aeruginosa isolates from patients exhibited different antibiotic sensitivities and genetic profiles compared to phacoemulsifier isolates.
- Patient isolates showed some genetic relatedness, while phacoemulsifier isolates were genetically diverse.
- Significant genetic variation was observed between patient and phacoemulsifier bacterial isolates.
Conclusions:
- Despite phenotypic similarity and close genetic ties among patient isolates, they differed genetically and in antibiogram from phacoemulsifier isolates.
- Phacoemulsifier isolates were genetically diverse but shared a similar antibiogram profile.
- The study could not conclusively establish Ringer's lactate from phacoemulsifiers as the source of infection.
Related Concept Videos
01:22Microbiome of the Eye
01:25Clinical Significance of Antibiotic Resistance