The corynebacterial flora of the normal human conjunctiva is lipophilic

Corynebacterium macginleyi in the era of MALDI-TOF MS: epidemiology, susceptibility patterns and prevalence of co-infection

Corynebacterium macginleyi has long been associated with ocular infections and has more recently been rarely implicated in systemic infections. There is a paucity of literature regarding the rate of C. macginleyi co-infection with other bacterial and viral pathogens and regarding the incidence of C. macginleyi infection in the paediatric population. In this study, we report 30 isolates of C. macginleyi of ocular origin from 26 patients, identified using matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS). The rates of co-isolation with bacterial and viral pathogens were 62% (n=16/26) and 39% (n=5/13), respectively, in this study. Of these, 13 patients had molecular testing performed as requested by treating clinicians for either the Chlamydia trachomatis/Neisseria gonorrhoeae PCR or herpes/enterovirus/adenovirus multiplex PCR. All isolates tested susceptible to linezolid, vancomycin and ciprofloxacin, with variable resistance to tetracycline, clindamycin and penicillin using EUCAST breakpoints.

Keratitis Caused by Candida parapsilosis and Subsequent Corynebacterium macginleyi Infection: Case Report and Short Review

Keratitis due to Candida parapsilosis or Corynebacterium macginleyi is uncommon. We present a patient with several risk factors who suffered two subsequent corneal infections caused by these pathogens and healed with topical conservative therapy. The important factor was the early detection of infection. Fluconazole solution administered topically as eye drops combined with regular debridement proved in this case a successful alternative to systemic antifungal treatment. With a perceived recurrence of the keratitis, one must take into account the involvement of other pathogens present. The previous use of an antifungal solution other than a conventional eye drop could be an additional risk factor for a second bacterial infection, but the benefits should still rule in favor of such a treatment.

Conjunctival Microbiome-Host Responses Are Associated With Impaired Epithelial Cell Health in Both Early and Late Stages of Trachoma

Background: Trachoma, a neglected tropical disease, is the leading infectious cause of blindness and visual impairment worldwide. Host responses to ocular chlamydial infection resulting in chronic inflammation and expansion of non-chlamydial bacteria are hypothesized risk factors for development of active trachoma and conjunctival scarring.

Methods: Ocular swabs from trachoma endemic populations in The Gambia were selected from archived samples for 16S sequencing and host conjunctival gene expression. We recruited children with active trachoma and adults with conjunctival scarring, alongside corresponding matched controls.

Findings: In children, active trachoma was not associated with significant changes in the ocular microbiome. Haemophilus enrichment was associated with antimicrobial responses but not linked to active trachoma. Adults with scarring trachoma had a reduced ocular bacterial diversity compared to controls, with increased relative abundance of Corynebacterium. Increased abundance of Corynebacterium in scarring disease was associated with innate immune responses to the microbiota, dominated by altered mucin expression and increased matrix adhesion.

Interpretation: In the absence of current Chlamydia trachomatis infection, changes in the ocular microbiome associate with differential expression of antimicrobial and inflammatory genes that impair epithelial cell health. In scarring trachoma, expansion of non-pathogenic bacteria such as Corynebacterium and innate responses are coincident, warranting further investigation of this relationship. Comparisons between active and scarring trachoma supported the relative absence of type-2 interferon responses in scarring, whilst highlighting a common suppression of re-epithelialization with altered epithelial and bacterial adhesion, likely contributing to development of scarring pathology.

Corynebacterium macginleyi conjunctivitis in Canada

This report describes for the first time Corynebacterium macginleyi as a cause of conjunctivitis in Canada, where menaquinone analysis was done as part of the strain characterization. This species is typically isolated from ocular surfaces of patients from Europe and Japan. The isolate was resistant to erythromycin and clindamycin.

Postoperative Corynebacterium macginleyi endophthalmitis

A 72-year-old man with chronic endophthalmitis who received steroid treatment for 3 months came to our center. Sterile endophthalmitis after cataract extraction had been diagnosed. Aqueous samples including smears, classic cultures, and polymerase chain reaction were taken for microbiological study. Amplified DNA was sequenced to identify the pathogen. Polymerase chain reaction amplification was positive for bacteria. Sequence analysis showed Corynebacterium macginleyi as the causal agent in 48 hours. The culture and smear stains from the ocular samples were negative. The patient was successfully treated with vancomycin. Polymerase chain reaction and subsequent DNA-typing were useful in detecting the microorganisms that caused the chronic endophthalmitis.