Ocular Microbiology and Immunology Group
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2014 OMIG Abstract 13

Candida parapsilosis Complex Exogenous Endophthalmitis and Biofilm Formation
Rodrigo Morizot, MD; Jose Alvaro Pereira Gomes MD, PhD; Ana Carolina Padovan, PhD;
Analy Salles de Azevedo Melo, PhD; Arnaldo Colombo, PhD; Ana Luisa Hofling-Lima, MD PhD
Federal University of São Paulo –UNIFESP, Brazil

Purpose: To analyze the molecular identification of species and biofilm formation levels to the difficulty in treating the patients and their outcome after 2 cases of C. parapsilosis species complex endophthalmitis after cataract surgeries.

Methods: Five samples of aqueous humor and vitreous were obtained from two different cases of endophthalmitis. From case A, two samples were collected. The first sample was collected 3 months after cataract surgery. After six months, another sample also showed positive for C. parapsilosis sensu stricto and also for Bacillus cereus The samples shows up sensitive to amphotericin-B, fluconazol and voriconazol. The patient was treated with multiple intravitreal injections of voriconazol without improvement of the framework. With that, we decided to remove the IOL, and noticed a marked improvement in their condition.
In case B, three samples were obtained two months from case A. The tests were positive for C. orthopsilosis sensitive to amphotericin-B, fluconazol and voriconazol, and it was decided to treat the patient with systemic and IVT voriconazol. Without any results, It was then decided to remove the tube shunt and IOL. All samples were sent to the microbiology section of the Federal University of São Paulo where phenotypic and ​​molecular identification (ITS rDNA amplification and sequencing) of isolates was performed. All isolates were tested for biofilm formation in 96-well plates with RPMI-1640 medium for 72h, at 37°C, and biofilm was quantified using the crystal violet (CV) staining method.

Results: All five isolates were phenotypically identified as C. parapsilosis species complex. By ITS sequence analysis, isolates from case A were identified as C. parapsilosis sensu stricto, and the three isolates from case B, as C. orthopsilosis. Biofilm quantification showed mean CV absorbance values of 1.420 and 1.616 for isolates from case A, classifying them as medium biofilm producers, and 2.611 to 2.787 for isolates from case B, classifying them as high biofilm producers.

Conclusions: We believe that the difficulty of treating the fungal endophthalmitis cases was closely linked to the high biofilm formation capacity of the strains, where biofilm served as a reservoir of yeasts that contributed to the persistence of infection. In fact, we achieved therapeutic success in the two reported cases only by mechanically removing the contaminated surfaces and IOL. Therefore, cases similar to those described here should be treated with mechanical removal of the contaminated surface once the persistence of the microorganism is detected.

Disclosure: N

2014 Agenda and Abstracts | < Previous | Next >