Genetic diversity and persistent colonization of Enterococcus faecalis on ocular surfaces

• Published in: Japanese journal of ophthalmology 2018-11, Vol.62 (6), p.699-705
• Main Authors: Todokoro, Daisuke, Eguchi, Hiroshi, Suzuki, Takashi, Suzuki, Motoo, Nakayama-Imaohji, Haruyuki, Kuwahara, Tomomi, Nomura, Takahiro, Tomita, Haruyoshi, Akiyama, Hideo
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Antibiotics; Bacterial proteins; Clinical Investigation; Clinical isolates; Colonization; Commensals; Conjunctiva - microbiology; Conjunctiva - pathology; DNA, Bacterial - analysis; Electrophoresis; Electrophoresis, Gel, Pulsed-Field; Endophthalmitis; Endophthalmitis - diagnosis; Endophthalmitis - microbiology; Enterococcus faecalis; Enterococcus faecalis - genetics; Enterococcus faecalis - isolation & purification; Eye; Eye Infections, Bacterial - diagnosis; Eye Infections, Bacterial - microbiology; Female; Gelatinase; Genetic diversity; Genetic Variation; Gram-Positive Bacterial Infections - diagnosis; Gram-Positive Bacterial Infections - microbiology; Humans; Male; Medicine; Medicine & Public Health; Middle Aged; Multilocus Sequence Typing; Mutation; Ophthalmology; Patients; Phenotypes; Polymerase Chain Reaction; Population characteristics; Pulsed-field gel electrophoresis; Retrospective Studies; Strains (organisms)
• ISSN: 0021-5155; 1613-2246
• DOI: 10.1007/s10384-018-0630-5

Purpose Enterococcus faecalis causes severe acute endophthalmitis and often leads to poor visual outcomes. Conjunctival bacterial cultures occasionally grow atypical bacteria including E. faecalis , which can potentially contribute to the development of postoperative endophthalmitis. However, the characteristics of these ocular E. faecalis strains are unknown. This study is the first attempt to determine the population characteristics of E. faecalis clinical isolates from eye infections and ocular commensals. Study design Retrospective Methods Twenty-eight E. faecalis ocular isolates were collected from 23 patients at 3 referring hospitals. The multilocus sequence typing (MLST) data were analyzed using the eBURST program. Phenotypes of cytolysin and gelatinase, antibiotic susceptibility, and mutations of the quinolone resistance-determining regions (QRDRs) of gyrA and parC were also examined. Pulsed-field gel electrophoresis (PFGE) was performed for strains from the same patients. Results PFGE revealed that 3 patients retained identical strains for 10 months to 2 and a half years. MLST identified 12 sequence types (STs), which were clustered into 3 clonal complexes (CCs) and 8 singletons, with ST179 the largest. Thirteen of the 23 isolates (56.5%) belonged to CC58, CC8, or CC2, which have previously been reported to be major CCs. Six of the 23 strains (26.0%) exhibited high-level quinolone resistance derived from mutations of the QRDRs in both gyrA and parC . Conclusions The sequence types of E. faecalis ocular isolates were divergent, with no eye-specific lineages observed. Persistent colonization of E. faecalis on the ocular surface was demonstrated in patients with chronic ocular surface diseases.