Identification of unknown ocular pathogens in clinically suspected eye infections using ribosomal RNA gene sequence analysis

Abstract

DNA sequence-based identification of pathogens from ocular samples of patients with clinically suspected eye infections was accomplished using 16S and internal transcribed spacer (ITS) ribosomal RNA gene sequence analysis. PCR was positive for 24 of 99 samples tested. Both culture and 16S rDNA sequence analysis identified Pseudomonas aeruginosa, streptococci and Enterobacteriaceae. Isolates misidentified as Burkholderia cepacia by biochemical tests were identified as Ralstonia mannitolilytica by 16S rDNA sequence analysis. Sequence analysis identified the following microorganisms from 19 culture-negative samples: Haemophilus influenzae, Sphingomonas sp., Klebsiella pneumoniae, Staphylococcus haemolyticus, Morganella morganii, Mycobacterium sp., Chryseobacterium sp., Pseudomonas saccharophila (Xanthomonas) and the fungus, Phaeoacremonium inflatipes.

In Vitro Susceptibility Profiles of Eight Antifungal Drugs against Clinical and Environmental Strains of Phaeoacremonium

“…Disseminated and severe infections were commonly associated with solid organ transplantation and other immunosuppressive conditions (3,(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27). Considering that the morphological identification of black fungi, and of Phaeoacremonium in particular, is problematic (28) and relies on sequencing of the internal transcribed space (ITS) ribosomal DNA (rDNA) region or ␤-tubulin or calmodulin genes (29)(30)(31), many cases in routine microbiology laboratories may have passed unnoticed (28). Also, there is a paucity of data pertaining to the antifungal therapy of infections due to these molds as no specific therapeutic regimen has been defined (32).…”

“…The organisms were identified to the species level by sequencing of the internal transcribed spacer regions of the rDNA region and partial ␤-tubulin gene (20,(29)(30)(31).…”

Phaeoacremonium: From esca disease to phaeohyphomycosis

“…In 2011 two Phaeoacremonium species were newly isolated from human infections. P. minimum was identified as the etiologic agent of a subcutaneous phaeohyphomycosis in Korea (Choi et al 2011) and Phaeoacremonium inflatipes was identified from an eye infection in the Philippines (Daroy et al 2011). Only one animal infection is known namely of P. parasiticum that was isolated from the blood and urine of a dog in California that had renal failure ).…”

“…To et al (2012) reported for the first time a culture-proven P. parasiticum respiratory tract infection in a severely immunocompromised patient and a case of airway colonization by P. parasiticum in a patient with past history of pulmonary tuberculosis. Two cases of eye infections caused by P. rubrigenum (Mostert et al 2005) and P. parasiticum (Daroy et al 2011) most probably also originated from aerial spores. A hospital ice dispenser was recently identified as source of P. parasiticum, which was associated with deficiencies in equipment cleaning (Blake et al 2014).…”

“…Together with Phaeoacremonium krajdenii, these two species have been the causal agents of most of the Phaeoacremonium infections. Both Phaeoacremonium inflatipes and Phaeoacremonium minimum (Choi et al 2011;Daroy et al 2011) have prior to their first detection from humans only been associated with woody plants. The factors contributing to P. parasiticum being the predominant species from humans are unknown.…”