Conjunctival sac flora and drug susceptibility analysis in normal children in East China.

PURPOSE: To investigate the distribution characteristics of conjunctival sac flora and assess the susceptibility of commonly used topical antimicrobial agents in normal children under the age of 18 in East China. METHODS: In 2019, a study was conducted at Qingdao Eye Hospital of Shandong First Medical University to analyze the microorganism cultures of conjunctival sac in 1258 normal children (2516 eyes; average age, 6.21 ± 3.78 years) in East China. Exclusion criteria included children with ocular surface diseases and those who had used any topical antimicrobial agents recently. The microorganism species in the conjunctival sac were analyzed using the M-38A protocol (microdilution method; investigators read the minimum inhibitory concentration [MIC] values) by the Clinical and Laboratory Standards Institute to determine drug susceptibility. RESULTS: The incidence of conjunctival sac microorganism in children was 32.87% (827/2516), a total of 541 cases (male 293, female 248). Children with conjunctival sac flora in a single eye were 255 and in both eyes were 286 (no statistical difference, P > 0.05). The concordance rate of children with binocular conjunctival sac flora was 32.16% (174/541; male 84, female 90). A total of 42 species of bacteria were detected. Children with Gram-positive cocci accounted for the highest proportion, 91.54% (757/827). The top three bacteria with the highest detection rates were Staphylococcus epidermidis (S. epidermidis; 52.12%), Streptococcus (12.09%), and Staphylococcus aureus (S. aureus; 10.76%). Streptococcus mitis (5.20%) accounted for the highest proportion of Streptococcus.S. epidermidis had the highest proportion in all age groups and was positively correlated with age (r = 0.89, P = 0.03). Before six years of age, the streptococcal proportion(mainly S. mitis) was greater than that of Staphylococcus aureus. The drug susceptibility analysis showed that S. epidermidis was most sensitive to gatifloxacin (98.61%), while it had the highest resistance rate to erythrocin (87.94%). S. aureus had the highest susceptibility to moxifloxacin (100%). Streptococcus was most sensitive to moxifloxacin (96.97%) and had the highest resistance rate to tobramycin (92.93%). CONCLUSIONS: Conjunctival sac flora in children was dominated by Gram-positive cocci, mainly S. epidermidis, S. aureus, and Streptococcus. S. epidermidis increased with age; the proportion of Streptococcus was higher than S. aureus among children aged 0-6 years. The typical conjunctiva sac flora was generally sensitive to quinolones, such as moxifloxacin and gatifloxacin; Streptococcus displayed high resistance to tobramycin antibiotics; and the female children had higher resistance to tobramycin than the male children.

A comparative study on two methods of ocular surface microbial sampling.

PURPOSE: To compare the effect of traditional conjunctival sac swab sampling (A) with aerosolization ocular surface microorganism sampling (B),a novel microbial sampling method, in detecting ocular microbial infection. METHODS: The study included 61 participants (122 eyes) enrolled at the Eye Hospital, Wenzhou Medical University from December, 2021 to March, 2023. Each eye of the participants underwent sampling first with method A then B.Before aerosolization sampling, the air environment was disinfected and sampled as blank air control sample. Subsequently, the air pulses impinging the ocular surface causes dehiscence of the tear film covering the ocular surface and aerosols are formed.The microorganisms from the ocular surface attach to the aerosols generated as aerosolization ocular surface microorganism and be sampled as subject sample by bio-aerosol sampler.The samples were collected and incubated at 25℃ for 3-5 days and 37℃ for 24-48 h.The colonies were counted and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RESULTS: The accuracy in Group B was higher than that in Group A (45.8% vs. 38.3%, P = 0.289). There was a slight level of agreement between the results from both the sampling methods (k = 0.031, P = 0.730). The sensitivity in Group B was higher than that in Group A (57.1% vs. 35.7%, P = 0.453). The specificity results in Group B was higher than that in Group A (44.3% vs. 38.7%, P = 0.480). There were 12 and 37 types of microbes detected in Groups A and B, respectively. CONCLUSIONS: Compared with traditional swab sampling, the novel aerosolization sampling method shows higher accuracy and more comprehensive detection of microbes; however, it cannot completely replace swab sampling. The novel method can be a novel conducive strategy and supplement swab sampling to auxiliary diagnose ocular surface infection.

Microbial distributions in the conjunctiva and lacrimal sacs of patients with chronic dacryocystitis in a tertiary hospital.

BACKGROUND: The aim was to clarify the distributions of bacteria in the conjunctival sac and lacrimal sac in patients with chronic dacryocystitis. METHODS: In total, 297 (322 eyes) chronic dacryocystitis patients who underwent nasal endoscopic dacryocystorhinostomy (EN-DCR) were included. Conjunctival sac secretions from the affected eye were collected preoperatively, and lacrimal sac retention fluid from the affected side in the same patient was collected intraoperatively. Bacterial culture and drug sensitivity testing were performed to determine bacterial distributions. RESULTS: In total, 127 bacterial isolates (49 species) were detected in 123 eyes in the conjunctival group, with a positivity rate of 38.2% (123/322); 85 bacterial isolates (30 species) were detected in 85 eyes in the lacrimal sac group, with a positivity rate of 26.4% (85/322). The positivity rates were significantly different (P = 0.001) between two groups. The gram-negative bacilli proportion in the lacrimal sac group (36/85, 42.4%) was significantly higher than that in the conjunctival sac group (37/127, 29.2%) ( P = 0.047). Positive conjunctival sac secretion culture (123/322) was significantly associated with increased ocular secretion (281/322, 87.3%) (P = 0.002). Among the culture-positive bacteria in the conjunctival sac group and the lacrimal sac group, 30/127, 23.6% and 43/127, 26.7% and 21/85, 24.7% and 20/85, 23.5% were resistant to levofloxacin and tobramycin, respectively. CONCLUSIONS: This study illustrated differences in bacterial distributions between conjunctival sac secretions and retained lacrimal sac fluid in chronic dacryocystitis patients, with a higher proportion of gram-negative bacilli in lacrimal sac secretions. The ocular surface flora in chronic dacryocystitis patients is partially resistant to levofloxacin and tobramycin, which need to be considered by ophthalmologists.

Case report of conjunctival sac fistula after cosmetic lateral canthoplasty.

BACKGROUND: To report a case of conjunctival sac fistula after cosmetic lateral canthoplasty which is rare. CASE PRESENTATION: A young women who underwent bilateral canthoplasty appeared with lacrimation of the right eye. We found there was a skin fistula with transparent tears at 2 mm lateral to the right canthus ligament and the liquid containing fluorescein was seen to overflow at the fistula after using fluorescein sodium eye drops. The number 7 lacrimal duct probe was visible under the temporal conjunctiva when exploring the fistula, and the fistula was about 4 mm. The patient was diagnosed with conjunctival sac fistula and fistula excision was performed. The patient did not tear abnormally after observation 3 months later and the incision healed well. CONCLUSIONS: The case report illustrates an uncommon post-lateral canthoplasty complication. We suggested that surgeons who perform this kind of surgery should ask about epiphora and look for conjunctival sac fistula at follow-up assessment.

Bacteriological profiles and drug susceptibility of Streptococcus isolated from conjunctival sac of healthy children.

BACKGROUND: To investigate bacterial flora and antibiotics susceptibility of Streptococcus pneumoniae isolated from the conjunctival sac of heathy children. METHODS: Bacteria were isolated from the secretions of conjunctival sac of healthy children between 2015 and 2018. Antimicrobial susceptibility of isolated S. pneumoniae strains were determined using microbroth dilution method. RESULTS: The sac secretions were collected from a total of 6440 children. 1409 samples presented bacterial growth, accounting for 21.8% of the samples. Among the 22 bacterial species isolated, 528 samples presented Gram-positive Staphylococcus spp. growth, accounting for 37.4% of the isolates, followed by Corynebacterium spp., counting for 30% of the isolates and Streptococcus pneumoniae, counting for 21.4% of the isolates. Antibiotics susceptibility tests showed that the majority of S. pneumoniae isolates were sensitive to most antibiotics tested. However, 72.8 and 81.2% of the isolates were resistant to erythromycin and tetracycline, respectively, and over 10% of them were resistant to gentamicin, tobramycin and rifampicin. CONCLUSIONS: The bacterial flora of healthy children is mainly consisted of Gram-positive bacteria belonging to Corynebacterium spp. and Streptococcus spp.; most of S. pneumoniae isolates were sensitive to antibiotics except erythromycin and tetracycline.

Reduction of Ocular Surface Damage and Bacterial Survival Using 0.05% Povidone-Iodine Ocular Surface Irrigation before Cataract Surgery.

BACKGROUND: To investigate the effects of 0.05% povidone-iodine (PI) irrigation on the ocular surface structure and bacterial survival rate in patients with cataract. METHODS: Ninety eyes of 90 patients with cataract were included. Before surgery, the operative field was irrigated with 0.05% PI and divided into 30-s, 1-, and 2-min groups. Anterior chamber fluid was cultured bacteriologically. Tear film breakup time (BUT), corneal fluorescein staining (CFS), lacrimal river height (LRH), and Schirmer test I (STI) were conducted to assess ocular surface. RESULTS: In all groups, the patients had significantly shorter postoperative BUT at 1 day, 3 days, and 1 week postoperatively than preoperatively. In addition, there was still lower BUT at 1 month postoperatively in the 1- and 2-min groups. STI and LRH were all decreased postoperatively at different time points (1 day, 3 days, 1 week), while CFS was increased. With the extension of time preoperatively (1 and 3 months), the ocular surface indicators returned to the preoperative level. The bacterial cultures after eye irrigating were negative in all groups. CONCLUSION: 0.05% PI irrigating the conjunctival sac for 30 s can achieve a low bacterial contamination rate. Importantly, it reduced the damage of ocular surface, which is beneficial to the recovery of ocular surface function.

Conjunctival aerobic bacterial flora in healthy Silesian foals and adult horses in Poland.

BACKGROUND: Commensal bacterial and fungal flora of the conjunctival sac has been described in horses and other animals. The identification of commensal flora of the conjunctival sac may aid in the diagnosis of ocular inflammatory diseases, such as conjunctivitis or more severe ulcerative keratitis, common in horses. Moreover, damage of ocular protective barriers may lead to an opportunistic infection. The study was carried out in Silesian horses kept at a single breeding center in South-western Poland, in order to limit any breed-dependant and climate-dependant variables affecting the results. Following an ophthalmic examination that revealed no abnormalities, sterile swabs were collected from conjunctival sac in 26 adult horses and 11 foals. The obtained swabs were subjected to bacterial culture testing. In case of Staphylococcus spp. isolation, susceptibility to methicillin was evaluated. RESULTS: Forty- three bacterial isolates, representing eleven genera of bacteria were cultured from 30 (81%) horses. Gram-positive bacteria were the dominant isolates (72%) (p < 0.001). The most commonly isolated Gram-positive bacteria were Staphylococcus spp., while Moraxella spp. were the most frequently isolated Gram-negative bacteria. There was no significant influence of sex and age on the frequency and type of microbial isolates. CONCLUSIONS: Commensal flora is present in the conjunctival sac of healthy horses in Poland. Age does not affect the abundance and type of microbial isolates.

Positive bacterial culture in conjunctival sac before cataract surgery with night stay is related to diabetes mellitus.

BACKGROUND: The aim of this study is to elucidate background clinical factors in patients with positive bacterial culture for the conjunctival sac before cataract surgery in Japan. METHODS: Retrospective review was made on medical records of 576 consecutive patients who underwent conjunctival sac culture before cataract surgery with night stay at a hospital in 2 years from January 2013 to December 2014. In the patients with sequential bilateral surgeries, the data were chosen for bacterial culture in the eye which had earlier surgery. The age at surgery ranged from 33 to 100 years (mean, 76.7 years). Clinical factors, analyzed in relation with positive or negative bacterial culture, included the sex, the age, the presence of hypertension or diabetes mellitus, history of cancer, and history of hospital-based surgery at other specialties. RESULTS: Bacterial culture of the conjunctival sac was positive in 168 patients while negative in 408 patients. In multiple regression analysis, the positive bacterial culture was related with the older age (P = 0.01), the presence of diabetes mellitus (P = 0.004), and the history of hospital-based surgery at other specialties (P = 0.001). CONCLUSIONS: Elderly patients with diabetes mellitus or previous hospital-based surgeries at other specialties have a higher rate of positive bacterial culture in the conjunctival sac before cataract surgery. This study would provide a hint for identifying patients at risk for carrying bacterial flora in the conjunctival sac.

Sustained release of brimonidine from conjunctival sac insert to reduce intraocular pressure for glaucoma treatment.

BACKGROUND: Glaucoma is one of the major irreversible blinding eye diseases in the world. Reducing intraocular pressure (IOP) is the primary treatment option, and taking eye drops daily is the common method. However, short drug duration and poor bioavailability of eye drops may lead to unsatisfied therapeutic effects and inadequate patient compliance. METHODS: A brimonidine-loaded silicone rubber insert (BRI@SR@PT) was prepared by loading brimonidine into a surface-modified silicone rubber ring, followed by polydopamine/thermoplastic polyurethane coatings. The physical properties, in vitro cytocompatibility and drug release of BRI@SR@PT were investigated. The BRI@SR@PT was administrated in the conjunctival sac of rabbit eyes, and its in vivo drug release, IOP-lowering efficacy and biosafety were assessed. RESULTS: The BRI@SR@PT presented great thermal stability and excellent elasticity. The BRI@SR@PT was able to release BRI sustainably for 28 days with little toxicity in vitro. Compared to BRI eye drops, the BRI@SR@PT effectively lowered IOP for 21 days based on the sustained BRI release with great biosafety when administrated in conjunctival sac of rabbit eyes in a noninvasive fashion. CONCLUSIONS: The conjunctival sac insert (BRI@SR@PT), as a promising drug-delivery platform, may provide a sustained IOP-lowering treatment for patients with ocular hypertension or glaucoma, without the need for invasive procedures.

Sustained release of brimonidine from polydimethylsiloxane-coating silicone rubber implant to reduce intraocular pressure in glaucoma.

Glaucoma is the leading cause of irreversible blindness, affecting 111 million people by 2040 worldwide. Intraocular pressure (IOP) is the only controllable risk factor for the disease and current treatment options seek to reduce IOP via daily taking eye drops. However, shortcomings of eye drops, such as poor bioavailability and unsatisfied therapeutic effects, may lead to inadequate patient compliance. In this study, an effective brimonidine (BRI)-loaded silicone rubber (SR) implant coated with polydimethylsiloxane (BRI@SR@PDMS) is designed and fully investigated for IOP reduction treatment. The in vitro BRI release from BRI@SR@PDMS implant reveals a more sustainable trend lasting over 1 month, with a gradually declined immediate drug concentration. The carrier materials show no cytotoxicity on human corneal epithelial cells and mice corneal epithelial cells in vitro. After administrated into rabbit's conjunctival sac, the BRI@SR@PDMS implant releases BRI in a sustained fashion and effectively reduces IOP for 18 days with great biosafety. In contrast, BRI eye drops only maintain IOP-lowering effect for 6 h. Therefore, as a substitute of eye drops, the BRI@SR@PDMS implant can be applied as a promising non-invasive platform to achieve long-term IOP-lowering in patients suffering from ocular hypertension or glaucoma.

Conjunctival sac microbiome in anophthalmic patients: Flora diversity and the impact of ocular prosthesis materials.

Purpose: To explore the changes of bacterial flora in anophthalmic patients wearing ocular prosthesis (OP) and the microbiome diversity in conditions of different OP materials. Methods: A cross-sectional clinical study was conducted, involving 19 OP patients and 23 healthy subjects. Samples were collected from the upper, lower palpebral, caruncle, and fornix conjunctiva. 16S rRNA sequencing was applied to identify the bacterial flora in the samples. The eye comfort of each OP patient was determined by a questionnaire. In addition, demographics information of each participant was also collected. Results: The diversity and richness of ocular flora in OP patients were significantly higher than that in healthy subjects. The results of flora species analysis also indicated that in OP patients, pathogenic microorganisms such as Escherichia Shigella and Fusobacterium increased significantly, while the resident flora of Lactobacillus and Lactococcus decreased significantly. Within the self-comparison of OP patients, compared with Polymethyl Methacrylate (PMMA), prosthetic material of glass will lead to the increased colonization of opportunistic pathogens such as Alcaligenes, Dermabacter and Spirochaetes, while gender and age have no significant impact on ocular flora. Conclusions: The ocular flora of OP patients was significantly different from that of healthy people. Abundant colonization of pathogenic microorganisms may have an important potential relationship with eye discomfort and eye diseases of OP patients. PMMA, as an artificial eye material, demonstrated potential advantages in reducing the colonization of opportunistic pathogens.

Characterization of Conjunctival Sac Microbiome from Patients with Allergic Conjunctivitis.

Conjunctival sac microbiome alterations have been reported to be closely associated with many ocular diseases. However, the characteristic of conjunctival sac microbiome in allergic conjunctivitis (AC) was scarcely described. In this study, we aimed to identify the differences of the conjunctival sac microbiome composition in AC patients compared with normal controls (NCs) using high-throughput 16S rDNA sequencing metagenomic analysis. The conjunctival sac microbiome samples from 28 AC patients and 39 NC patients were collected. The V3-V4 region of 16S rRNA gene high-throughput sequencing was performed on the illumina MiSeq platform. Alpha diversity, beta diversity and the relative abundance at the phylum and genus levels were analyzed using QIIME. Alpha diversity demonstrated by Chao1, Observed_species and PD_whole_tree indexes did not show significant difference between the AC and NC groups, while the Shannon index was higher in the AC group. Beta diversity showed divergent microbiome composition in different groups (p < 0.005). The top five abundant phyla were Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota and Cyanobacteria in both groups. The top five abundant genera were Bacillus, Staphylococcus, Corynebacterium, Acinetobacter and Ralstonia in the AC group and Acinetobacter, Staphylococcus, Bacillus, Clostridium_sensu_stricto_1, Corynebacterium and Geobacillus in the NC group. The Firmicutes/Bacteroidetes (F/B) ratio at the phylum level was similar between groups (p = 0.144). The Bacillus/Acinetobacter (B/A) ratio at the genus level was higher in the AC group (p = 0.021). The dysbiosis detected in this study might provide further evidence to investigate the mechanism and treatment methods for allergic conjunctivitis.

Differentially Expressed Genes of Pseudomonas aeruginosa Isolates from Eyes with Keratitis and Healthy Conjunctival Sacs.

Background: Pseudomonas aeruginosa (P. aeruginosa) is the second-most common commensal bacterium in healthy conjunctival sacs. When the corneal epithelial barrier is damaged, P. aeruginosa in a healthy conjunctival sac can cause infectious keratitis, which can result in the loss of vision. This study was designed to investigate the differentially expressed genes (DEGs) of P. aeruginosa isolates from eyes with keratitis and from healthy conjunctival sacs to predict their functions and pathways through Illumina high-throughput RNA sequencing (RNA-seq). Methods: P. aeruginosa isolates from keratitis and healthy conjunctival sacs were obtained. The transcriptome profile of P. aeruginosa was characterized by a high throughput RNA-seq strategy using the Illumina HiSeq 2500 platform. The DEGs were analyzed with DESeq and validated through quantitative real-time polymerase chain reaction (PCR) and with experimental mice. GO enrichment and the KEGG pathway were also analyzed. Results: In genome-wide transcriptional analysis, 557 genes (332 upregulated and 225 downregulated) were found to be differentially expressed (fold change ≥ 2, p ≤ 0.05) in the strains from keratitis. GO enrichment analysis suggested that DEGs tended to be associated with cellular and metabolic processes. KEGG pathway analysis revealed the DEGs were typically associated with the pathways of the bacterial secretion system and pyoverdine metabolism. Eleven DEGs were validated using quantitative reverse-transcription PCR and verified with experimental mice. The results were consistent with those obtained in RNA-seq. Conclusion: The DEGs related to pilin, T2SS, T3SS, and pyoverdine metabolisms were significantly altered in the strains from keratitis. The findings may be helpful for further investigations on genes or pathways related to the pathogenesis of and therapeutic targets for P. aeruginosa keratitis.

Conjunctival Swab Findings in 484 COVID-19 Patients in Four Hospital Centers in Slovakia.

Since 2020, the COVID-19 (Coronavirus Disease 2019) has quickly become a worldwide health problem. Ophthalmologists must deal with symptoms as well. For the positive detection in the conjunctival sac swab in COVID-19 patients hospitalized in Slovakia during March 2021 in four hospital centers, we used a test based on a polymerase chain reaction (PCR). In a group of 484 patients, 264 males (55%) and 220 females (45%) with clinical symptoms were identified with COVID-19 as a clinical diagnosis. The PCR test swab results from the conjunctival sac taken on the same day were positive in 58 patients (12%), 31 males (with a mean age of 74.6 ± 13.59 years) and 27 females (with a mean age of 70.63 ± 14.17 years); negative in 417 patients (86%); and 9 patients (2%) had an unclear result. The cycle threshold values comparing the nasopharynx and conjunctiva were also different in the group of all patients divided by age and gender. In COVID-19 patients the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was detectable using PCR test in the nasopharynx but also in the conjunctival sac swab, where the positivity rate was only 12%.

Sustained release of brimonidine from BRI@SR@TPU implant for treatment of glaucoma.

Glaucoma is the leading cause of irreversible vision loss worldwide, and reduction of intraocular pressure (IOP) is the only factor that can be interfered to delay disease progression. As the first line and preferred method to treat glaucoma, eye drops have many shortcomings, such as low bioavailability, poor patient compliance, and unsustainable therapeutic effect. In this study, a highly efficient brimonidine (BRI) silicone rubber implant (BRI@SR@TPU implant) has been designed, prepared, characterized, and administrated for sustained relief of IOP to treat glaucoma. The in vitro BRI release from BRI@SR@TPU implants shows a sustainable release profile for up to 35 d, with decreased burst release and increased immediate drug concentration. The carrier materials are not cytotoxic to human corneal epithelial cells and conjunctival epithelial cells, and show good biocompatibility, which can be safely administrated into rabbit's conjunctival sac. The BRI@SR@TPU implant sustainably released BRI and effectively reduced IOP for 18 d (72 times) compared to the commercial BRI eye drops (6 h). The BRI@SR@TPU implant is thus a promising noninvasive platform product for long-term IOP-reducing in patients with glaucoma and ocular hypertension.

Are Prophylactic Systemic Antibiotics Required in Patients with Cataract Surgery at Local Anesthesia?

The reduced use of antimicrobial drugs has been recommended worldwide, according to the global action for antimicrobial resistance published in 2015 by the World Health Organization. In this study, we retrospectively reviewed the incidence of surgical site infection in consecutive patients with cataract surgeries at a single hospital in the 6-year process when prophylactic systemic antibiotics were reduced in a step-by-step manner. The entire study period from 2016 to 2022 was divided into five stages, based on the use of systemic antibiotics. In stage 1 with 649 cataract surgeries, an intravenous drip infusion of cefazolin 1 g was given at surgery, followed by oral cefdinir 100 mg in the evening on surgery day and three times for two postoperative days. In stage 2 with 541 cataract surgeries, oral cefdinir 100 mg was given in the late morning before surgery, in the evening, and three times (300 mg in total) for two postoperative days. In stage 3 with 103 cataract surgeries, oral levofloxacin 500 mg was given in the late morning before surgery and once in the morning for two postoperative days. In stage 4 with 545 cataract surgeries, oral levofloxacin 500 mg was given only in the late morning before surgery. In stage 5 with 311 cataract surgeries, no systemic antibiotics were given. As common procedures in all stages, moxifloxacin eye drops were given four times daily as topical antibiotics in the 3 days before surgery and about 2 weeks after surgery. At surgery, the ocular surface was frequently irrigated with saline-diluted povidone iodine at 0.5% working concentration. No postoperative infection was recorded in any stage. This study showed neither harm nor risk in reduced use and, consequently, no use of prophylactic systemic antibiotics in cataract surgery as far as local precautionary measures were secured.

Composition and Diversity of the Ocular Surface Microbiota in Patients With Blepharitis in Northwestern China.

Purpose: To investigate the composition and diversity of the microbiota on the ocular surface of patients with blepharitis in northwestern China via 16S rDNA amplicon sequencing. Methods: Thirty-seven patients with blepharitis divided into groups of anterior, posterior and mixed blepharitis and twenty healthy controls from northwestern China were enrolled in the study. Samples were collected from the eyelid margin and conjunctival sac of each participant. The V3-V4 region of bacterial 16S rDNA in each sample was amplified and sequenced on the Illumina HiSeq 2500 sequencing platform, and the differences in taxonomy and diversity among different groups were compared. Results: The composition of the ocular surface microbiota of patients with blepharitis was similar to that of healthy subjects, but there were differences in the relative abundance of each bacterium. At the phylum level, the abundances of Actinobacteria, Cyanobacteria, Verrucomicrobia, Acidobacteria, Chloroflexi, and Atribacteria were significantly higher in the blepharitis group than in the healthy control group, while the relative abundance of Firmicutes was significantly lower (p < 0.05, Mann-Whitney U). At the genus level, the abundances of Lactobacillus, Ralstonia, Bacteroides, Akkermansia, Bifidobacterium, Escherichia-Shigella, Faecalibacterium, and Brevibacterium were significantly higher in the blepharitis group than in the healthy control group, while the relative abundances of Bacillus, Staphylococcus, Streptococcus, and Acinetobacter were significantly lower in the blepharitis group (p < 0.05, Mann-Whitney U). The microbiota of anterior blepharitis was similar to that of mixed blepharitis but different from that of posterior blepharitis. Lactobacillus and Bifidobacterium are biomarkers of posterior blepharitis, and Ralstonia is a biomarker of mixed blepharitis. There was no significant difference in the ocular surface microbiota between the eyelid margin and conjunctival sac with or without blepharitis. Conclusion: The ocular surface microbiota of patients with blepharitis varied among different study groups, according to 16S rDNA amplicon sequencing analysis. The reason might be due to the participants being from different environments and having different lifestyles. Lactobacillus, Bifidobacterium, Akkermansia, Ralstonia, and Bacteroides may play important roles in the pathogenesis of blepharitis.

Allogeneic Cultivated Limbal Epithelial Sheet Transplantation in Reconstruction of Conjunctival Sac After Chemical and Thermal Burns.

The study aims to evaluate the effect of allogeneic cultivated limbal epithelial cell sheet transplantation (CLET) in reconstructing conjunctival sac for severe symblepharon after chemical and thermal burns. A retrospective, non-comparative case series. Thirty-six eyes (36 patients) underwent CLET for severe symblepharon and conjunctival sac stenosis or atresia. Symblepharon was separated, and pseudopterygium was preserved to replace the palpebral conjunctiva. Allogeneic cultivated limbal epithelial cell sheet using human amniotic membrane as a carrier was transplanted into the recipient's eye to reconstruct the conjunctival sac. The effect of conjunctival sac reconstruction, eye and eyelid movement, ocular surface restitution, and symblepharon recurrence were analyzed after surgery. Symblepharon was completely relieved in 30 of the 36 eyes (83.3%) by a single surgical procedure, with fornix reconstruction, as well as free movement of eye globe and eyelids. Strip-like symblepharon remained in 6 eyes (16.7%) and was completely relieved after the second CLET. Twenty patients without visual function received prostheses 3 months after surgery and the other sixteen patients underwent different corneal transplantation for visual acuity improvement. During the follow-up period, no one had symblepharon recurrence. The transplantation of cultivated allogeneic limbal epithelial sheets offers an effective and safe alternative in the treatment of symblepharon and reconstruction of conjunctival sac in eyes with severe ocular burns, which lays the foundation for subsequent treatments.

Chloramphenicol/sulfobutyl ether-ß-cyclodextrin complexes in an ophthalmic delivery system: prolonged residence time and enhanced bioavailability in the conjunctival sac.

Objective: Conventional chloramphenicol (CHL) eye drops are widely used anti-infection formulations for acute bacterial conjunctivitis. However, the therapeutic effects are limited by insufficient concentration in the conjunctival sac. Hence, the objective of this study is to formulate and develop novel CHL eye drops with improved topical concentrations by increasing the solubility and decreasing the transcorneal penetration. Research design and methods: CHL was included in the sulfobutyl ether-ß-cyclodextrin (SBE-ß-CD) using the freeze-drying method. Eye drops containing CHL/SBE-ß-CD complexes were prepared and evaluated for in vitro and in vivo studies. Results: The formation of CHL/SBE-ß-CD inclusion was confirmed by DSC, XRD, NMR, and SEM. The aqueous solubility of CHL was significantly enhanced, and the drug transcorneal penetration was inhibited after inclusion. The CHL/SBE-ß-CD displayed sustained release profiles. The tear fluid elimination kinetic study showed that the CHL/SBE-ß-CD eye drops had better ability to prolong the residence time, and significantly increase CHL concentration in the conjunctival sac. Besides, it was shown that CHL/SBE-ß-CD eye drops were nonirritating to rabbits' eyes. Conclusions: The SBE-ß-CD inclusions offer a potential alternative strategy for ocular administration of poorly water-soluble drugs in the conjunctival sac.