Delineation of the bacterial composition in exogenous endophthalmitis using 16S rDNA sequencing.

PURPOSE: To determine the bacterial spectrum of exogenous endophthalmitis of different origins, namely, posttraumatic, postcataract surgery, filtering bleb-associated, and intravitreal treatment-related endophthalmitis, using the 16S rDNA sequencing method. METHODS: Aqueous humor or vitreous humor samples were collected from 24 endophthalmitis patients. Traditional cultivation and 16S rDNA sequencing were conducted with these samples. Three senile cataract controls and one intraocular irrigating solution were used as sequencing control. RESULTS: Eleven of the 24 samples (45.8%) obtained positive bacterial cultivation, and each sample positive for only one species. The 11 culture-positive species could all be identified in their corresponding sequencing results, but only four strains being the top one pathogen in the sequencing. A total of 567 species were isolated using 16S rDNA sequencing, with the top five species being Pseudomonas sp., Staphylococcus epidermidis, Staphylococcus sp., Streptococcus sp., and Enterococcus faecalis. The dominant bacterial strains varied among the different endophthalmitis categories but with no significant difference in the overall bacterial spectrum. Bacterial atlas containing Pseudomonas, Streptococcus, Staphylococcus, Actinomycetales_unclassified, Thermus, and Janibacter was shared by the four categories. Aqueous humor bacterial profile showed a higher overlap with contaminating bacteria from the environment. CONCLUSIONS: 16S rDNA sequencing is more efficient for endophthalmitis pathogen screening than the traditional cultivation method in terms of positive detection rate and the number of bacteria identified. But the risk of environmental contamination exists when using 16S rDNA sequencing method for endophthalmitis diagnosis. Different categories of endophthalmitis displayed diversified bacterial composition.

Acute Infectious Endophthalmitis After Cataract Surgery: Epidemiological Characteristics, Risk Factors and Incidence Trends, 2008-2019.

OBJECTIVE: Intended to investigate the epidemiological characteristics, risk factors and incidence trend of endophthalmitis after cataract surgery in recent 12 years. METHODS: A retrospective study was conducted on the patients who underwent cataract surgery in Qingdao Eye Hospital from January 1, 2008, to December 31, 2019, including age, sex, history of diabetes, intraoperative operation and complications. In addition, the related risk factors and incidence trend of acute infective endophthalmitis were analyzed. The incidence of endophthalmitis and its related factors were analyzed by univariate and multivariate logistic regression analysis. RESULTS: A total of 55,612 cases of cataract surgery were performed in our hospital in 12 years, and 42 cases of acute infective endophthalmitis occurred (the incidence rate was 0.076%). The average occurrence time was 10.57 days ± 11.17, with eye pain as the main complaint and anterior chamber fibrin exudation as the main clinical manifestation. In addition, there were eight cases of anterior chamber hypopyon and 18 cases of vitreous reaction, the results of anterior aqueous humor or vitreous fluid culture in 10 patients were positive. Univariate analysis showed that intraoperative rupture of posterior capsule, non-use of antibiotics and non-use of behind-the-lens washout were the risk factors of infectious endophthalmitis after cataract surgery (P=0.032, P=0.000, P=0.000). Besides, multivariate logistic regression analysis showed that intraoperative rupture of posterior capsule was the main risk factor. CONCLUSION: The occurrence of endophthalmitis after cataract surgery is mainly related to intraoperative rupture of posterior capsule, absence of antibiotics and behind-the-lens washout. In addition, the incidence of endophthalmitis after cataract surgery decreased during the past 12 years.

Effects of Dietary Fat Profile on Gut Microbiota in Valproate Animal Model of Autism.

Autism spectrum disorder (ASD) is a developmental disability which may cause significant social, communication, and behavioral challenges. Besides certain essential symptoms, a lot of ASD individuals also suffer the comorbidity of gut microbiota dysbiosis, which possibly causes a variety of gastrointestinal (GI) difficulties. Interestingly, evidence has indicated that behavioral output may be modulated through the communication between the central nervous system and gut microbiota via the gut-brain axis. Polyunsaturated fatty acids (PUFAs) and n-3 fatty acids (n-3 PUFA) are structurally and functionally crucial components for the brain, and the state of n-3 PUFAs also affects the gut microbiota. However, how varying intake ratios of n-3/n6 PUFAs affect the gut microbiota composition in ASDs is not well-understood. Pregnant female Wistar rats with intraperitoneal administration of valproate acid (VPA) at embryonic day (E) 12.5 and their male offspring were grouped and fed three diets: a control chow (VPA group), omega-3 deficient (A group), and n-3/n6 (1:5) diet (B group). The diet of pregnant female Wistar rats with intraperitoneal administration of saline and their male offspring was a control chow (normal group). Microbial composition and species abundance were investigated accordingly by the 16S rRNA gene-based metagenomics analysis on the fecal samples. Results showed that fecal microbial abundance was decreased because of VPA administration in the period of pregnancy, and the changing pattern of gut microbiota was similar to that reported in ASD patients. Furthermore, the n-3/n6 (1:5) diet increased the fecal microbial abundance and decreased the elevated Firmicutes. In conclusion, n-3/n6 PUFAs (1:5) diet supplementation may alter gut microbiota composition in VPA-exposed rats. This study put forward a new strategy for the intervention and treatment of autism by n-3/n-6 PUFAs ratio supplementation intakes.

Efficacy of 0.5% Levofloxacin and 5.0% Povidone-Iodine Eyedrops in Reducing Conjunctival Bacterial Flora: Metagenomic Analysis.

Bacteria associated with postoperative endophthalmitis mostly originate from the normal bacterial flora of the patient's conjunctiva and eyelids, so the incidence of endophthalmitis may be reduced by eliminating the ocular and adnexal flora before surgery. We assessed the effectiveness of eyedrops of 0.5% levofloxacin and 5.0% povidone-iodine (PVI) in reducing conjunctival bacterial flora by metagenomic analysis. A total of 2.4 × 106 high-quality sequencing reads were generated from 93 conjunctival samples obtained from 31 eyes scheduled for cataract surgery before prophylactic therapy (group 1), after administration of 0.5% levofloxacin eyedrops into the conjunctival sac 8 times before surgery (group 2), and at 3 minutes after instillation of 5.0% PVI solution in the conjunctival sac (group 3) followed by surgery irrigation. The alpha diversity and beta diversity results demonstrated that group 3 had the least richness and biodiversity. Corynebacterium, Pseudomonas, Staphylococcus, Acinetobacter, and Streptococcus were predominant in all samples. The relative abundance of these bacterial species was 30.94%, 27.48%, 5.26%, 4.55%, and 2.61% in group 1, 16.32%, 44.10%, 2.19%, 5.39%, and 0.97% in group 2, and 5.90%, 65.55%, 0.39%, 5.36%, and 0.10% in group 3, respectively. The most easily and difficultly eliminated were Corynebacterium and Pseudomonas, respectively. In conclusion, the metagenomic analysis using high-throughput sequencing provides a scientific way for evaluating the effectiveness of a disinfection method from the perspective of analyzing the composition and diversity of the conjunctival microbiome. Despite the use of preoperative antisepsis regimens, the ocular surface of patients receiving cataract surgery could not be rendered completely aseptic, indicating that more strict disinfection methods need to be adopted to reduce the risk for anterior chamber contamination and endophthalmitis after cataract surgery.

Conjunctival microbiome changes associated with fungal keratitis: metagenomic analysis.

AIM: To investigate the ocular surface microbiome profile of patients with fungal keratitis (FK) through bacterial 16S rDNA sequencing. METHODS: The swab samples were collected from 8 patients with FK (Group 1 from the corneal ulcer, Group 2 from the conjunctival sac of the infected eyes, and Group 3 from the conjunctival sac of the fellow eyes) and 10 healthy eyes (Group 4 from the conjunctival sac). Bacterial 16S rDNA V4-V5 region sequencing was performed to characterize the bacterial communities on the ocular surfaces of the patients with FK. RESULTS: Our metagenomic data showed that 97% of the sequence reads were categorized into 245 distinct bacterial genera, with 67.75±7.79 genera detected in Group 1, 73.80±13.44 in Group 2, 74.57±14.14 in Group 3, and 89.60±27.49 in Group 4. Compared with the healthy eyes (Group 4), both infected (Groups 1 and 2) and fellow eyes (Group 3) of the patients with FK showed reduced bacterial diversity and altered ocular surface microbiota compositions, with lower abundance of Corynebacterium and Staphylococcus and higher abundances of Pseudomonas, Achromobacter, Caulobacter and Psychrobacter. CONCLUSION: Our report depicts the altered ocular surface bacterial community structures both in the affected and fellow eyes of patients with FK. These changes may contribute to the pathogenesis of FK or the increased risk for FK.