Pseudomonas aeruginosa blepharoconjunctivitis during cytoreductive chemotherapy in a woman with acute lymphocytic leukemia

Characteristics of bacterial community in eyelashes of patients with Demodex blepharitis

BACKGROUND

Demodex blepharitis (DB) is a common disease of the ocular surface. The characteristics of the bacterial community in eyelash roots after Demodex infestation are still unknown. Knowledge of the characteristics of the bacterial community of eyelash follicles in patients with DB can provide valuable insights for guiding the diagnosis and treatment of DB.

METHODS

Twenty-five patients with DB (DB group) and 21 non-DB volunteers (control group) were enrolled in the study. Eyelashes from the upper eyelid of the right eye were sampled, and 16S ribosomal DNA (rDNA) sequencing was performed to determine the V3-V4 regions of the microbial 16S rDNA gene within 1 month of infestation. The sequencing data of the two groups were analyzed and compared. The effect of the bacterium Burkholderia on the survival of Demodex mites was evaluated using Demodex obtained from 12 patients with DB other that the patients in the DB group.

RESULTS

A total of 31 phyla and 862 genera were identified in the DB and control groups. The five most abundant phyla in the two groups were Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Cyanobacteria. The abundance of Actinomycetes was significantly higher in the DB group than in the control group. At the genus level, the five most abundant genera in the two groups were Pseudomonas, Burkholderia-Caballeronia-Paraburkholderia, Rolstonia and Acinetobacter; Clostridium sensu stricto 1 was abundant in the control group and Corynebacterium_1 was abundant in the DB group. Compared with the control group, the abundance of Burkholderia-Caballeronia-Paraburkholderia was 2.36-fold lower in the DB group. Linear discriminant analysis Effect Size (LEfSe) analysis revealed Burkholderia-Caballeronia-Paraburkholderia, SC_I_84_unclassified, Nonmyxobacteria and Succinvibrio to be the major biomarkers in the control group and Catenibacterium and Lachnospiraceae NK4A136 group to be the major biomarkers in the DB group. To explore the performance of these optimal marker models, receiver operational characteristic curve analysis was performed, and the average area under the curve value of Burkholderia-Caballeronia-Paraburkholderia was 0.7448. Burkholderia cepacia isolated from normal human eyelashes was fermented, and the Demodex mites isolated from patient eyelashes were cultured together with its fermented supernatant. The results showed that the fermentation supernatant could significantly reduce the survival time of the Demodex mites, suggesting the potential therapeutic value of this bacterium against Demodex.

CONCLUSIONS

The composition of the bacterial community in the eyelashes of DB patients differed from that in eyelashes of healthy volunteers, revealing a decrease in bacterial diversity in infested eyelashes. This decrease may be related to the occurrence and development of DB. The supernatant of Burkholderia cepacia culture medium was found to inhibit the growth of Demodex in eyelash hair follicles, providing a new insight with potential applications for the clinical treatment of Demodex infestation.

A Case of Chronic Conjunctivitis following Rituximab Therapy

The activity of the anti-CD20 monoclonal antibody, rituximab in B-cell non-Hodgkin's lymphoma, with relatively minimal toxicity has been well established. Adverse effects such as low-grade fever, urticaria, bronchospasm, sporadic tachycardia, and hypotension have been described. However, only a single case of rituximab-related, transient conjunctivitis has been documented in literature. We report an occurrence of chronic, bilateral conjunctivitis in an 88-year-old female diagnosed with stage IV, non-Hodgkin's lymphoma (NHL), who was maintained on rituximab for 12 months. In contrast to the previously described case, our patient developed severe conjunctival inflammation approximately three to four weeks following rituximab induction. Resolution of conjunctivitis occurred within two months after cessation of rituximab treatment.

Pseudomonas aeruginosa induces interleukin-8 (IL-8) gene expression in human conjunctiva through the recruitment of both RelA and CCAAT/enhancer-binding protein beta to the IL-8 promoter

The purpose of this study was to identify the Pseudomonas aeruginosa-activated signaling pathway leading to interleukin (IL)-8 gene expression and protein synthesis by human conjunctival epithelium. IL-8 protein and mRNA were determined by enzyme-linked immunosorbent assay and reverse transcription-PCR, respectively. Activation of MAPKs and NF-kappaB was analyzed by Western blotting using phosphospecific antibodies. We used transfection with wild-type or mutated IL-8 promoters and cotransfection with transcription factor overexpressing plasmids or small interfering RNAs. Electrophoretic mobility shift assay and chromatin immunoprecipitation (ChIP) were performed for in vitro and in vivo protein-DNA binding studies, respectively. P. aeruginosa increased IL-8 expression at the transcriptional level by phosphorylating CCAAT/enhancer-binding protein beta (C/EBPbeta) via p38MAPK and activating NF-kappaB. The simultaneous involvement of RelA and C/EBPbeta and the integrity of the corresponding consensus sites were required, whereas c-Jun was involved only in basal IL-8 expression. Re-ChIP experiments showed that RelA and C/EBPbeta act together at the IL-8 promoter level upon P. aeruginosa infection. Taken together, our results suggest that P. aeruginosa induces IL-8 promoter expression and protein production in conjunctival epithelial cells by activating RelA and C/EBPbeta and by promoting the cooperative binding of these transcription factors to the IL-8 promoter that in turn activates transcription.

Ophthalmic manifestations of acute leukaemias: the ophthalmologist's role

With evolving diagnostic and therapeutic advances, the survival of patients with acute leukaemia has considerably improved. This has led to an increase in the variability of ocular presentations in the form of side effects of the treatment and the ways leukaemic relapses are being first identified as an ocular presentation. Leukaemia may involve many ocular tissues either by direct infiltration, haemorrhage, ischaemia, or toxicity due to various chemotherapeutic agents. Ocular involvement may also be seen in graft-versus-host reaction in patients undergoing allogeneic bone marrow transplantation, or simply as increased susceptibility to infections as a result of immunosuppression that these patients undergo. This can range from simple bacterial conjunctivitis to an endophthalmitis. Leukaemia can present as pathology in the adnexae, conjunctiva, sclera, cornea, anterior chamber, iris, lens, vitreous, retina, choroid, and optic nerve. Recognition of the varied ocular presentations is also important in assessing the course and prognosis of leukaemia. We have presented a systematic approach taking each part of the eye in turn and outlining how leukaemia has been shown to affect it.