Newer emerging pathogens of ocular non-sporulating molds (NSM) identified by polymerase chain reaction (PCR)-based DNA sequencing technique targeting internal transcribed spacer (ITS) region.
OBJECTIVE
To apply Polymerase Chain Reaction (PCR)-based DNA sequencing targeting Internal Transcribed Spacer (ITS) region for identification of non-sporulating molds (NSM) to species level which formed 12% of ocular isolates of fungi in a tertiary eye hospital in South India.


METHODS
Fifty ocular filamentous fungal NSM isolates recovered from 45 patients were included in the study. PCR-based DNA sequencing technique targeting ITS region was applied to identify NSM.


RESULTS
PCR-based DNA sequencing revealed 23 established pathogens involving 8 genera (Aspergillus, Fusarium, Bipolaris, Pythium, Cochilobolus, Exserohilum, Pseudoallescheria, and Scedosporiumspecies) and 27 emerging pathogens involving 7 genera (Botryosphaeria Lasiodiplodia species, Thielavia tortuosa, Glomerulla singulata, Macrophomina phaseolina, Rhizoctonia bataticola, and Podosporaspecies) reported for the first time in literature related to ocular infections. Fifteen (30%) patients with fungal keratitis caused by NSM failed to respond to standard antifungal therapy.


CONCLUSIONS
PCR-based DNA sequencing technique is a rapid, reliable, and valuable tool to identify 54% of NSM as newer potential pathogens of fungi causing ocular mycoses.
Bagyalakshmi
R
R
L & T Microbiology Research Centre, Vision Research Foundation, Chennai, India.
Therese
K L
KL
Prasanna
S
S
Madhavan
H N
HN
D001483:Base Sequence; D003320:Corneal Ulcer / Q000382:microbiology*; D004271:DNA, Fungal / Q000032:analysis; D021903:DNA, Ribosomal Spacer / Q000032:analysis*; D015821:Eye Infections, Fungal / Q000382:microbiology*; D005658:Fungi / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008969:Molecular Sequence Data; D016533:Mycological Typing Techniques; D009181:Mycoses / Q000382:microbiology*; D016133:Polymerase Chain Reaction
D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer