Resumen

FARINA, Norma et al. Diagnosis of endophthalmitis by molecular and conventional microbiological methods in patients from ophthalmologic centers of Paraguay. Mem. Inst. Investig. Cienc. Salud [online]. 2019, vol.17, n.2, pp.77-85. ISSN 1812-9528.  https://doi.org/10.18004/mem.iics/1812-9528/2019.017.02.77-085.

Infectious endophthalmitis is a serious intraocular condition, although it is rare, often results in vision loss. The early etiological diagnosis and appropriate treatment leads to a better outcome. Conventional microbiological techniques have low sensitivity in the diagnosis of infectious endophthalmitis, however polymerase chain reaction (PCR) is a more sensitive method which is widely used. The goal was to determine the etiology of infectious endophthalmitis by culture and PCR in patients who consulted in ophthalmologic centers in Asunción, Paraguay. Vitreous fluid samples obtained by puncture from 51 patients with endophthalmitis were studied. Samples were divided into two aliquots; one was used for the conventional microbiological study and the other for the nested PCR. The latter uses a pair of primers based on conserved sequences of the 16S gene ribosomal and specific primers for gram positive bacteria. Detection sensitivity of the nested PCR was 3.10-5 ng / μl for S. aureus, 2.5.10-3 ng / μl for S. pneumoniae and 6.10-7 ng / μl for E. coli. Out of 51 samples, 12 (23.5%) were positive for conventional microbiological methods and 26 (51.0%) by nested-PCR. Gram-positive bacteria were predominant 8/11 (73%) by culture and one filamentous fungus was isolated. The nested PCR presented very good sensitivity and very useful for the identification of the bacterial origin of endophthalmitis, improving culture sensitivity in 27.5%. Bacterial discrimination in Gram positive and Gram negative by PCR correlated 100% with the culture.

Palabras clave : bacterial endophthalmitis; etiology; PCR; culture; sensitivity; molecular diagnosis.

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