Clinical Features and Treatment Outcomes of Carbapenem-Resistant Pseudomonas aeruginosa Keratitis.

Importance: Evaluation of the microbiological diagnostic profile of multidrug-resistant Pseudomonas aeruginosa keratitis and potential management with rose bengal-photodynamic antimicrobial therapy (RB-PDAT) is important. Objective: To document the disease progression of carbapenemase-resistant P aeruginosa keratitis after an artificial tear contamination outbreak. Design, Setting, and Participants: This retrospective observation case series included 9 patients 40 years or older who presented at Bascom Palmer Eye Institute and had positive test results for multidrug-resistant P aeruginosa keratitis between January 1, 2022, and October 31, 2023. Main Outcomes and Measures: Evaluation of type III secretion phenotype, carbapenemase-resistance genes blaGES and blaVIM susceptibility to antibiotics, and in vitro and in vivo outcomes of RB-PDAT against multidrug-resistant P aeruginosa keratitis. Results: Among the 9 patients included in the analysis (5 women and 4 men; mean [SD] age, 73.4 [14.0] years), all samples tested positive for exoU and carbapenemase-resistant blaVIM and blaGES genes. Additionally, isolates were resistant to carbapenems as indicated by minimum inhibitory concentration testing. In vitro efficacy of RB-PDAT indicated its potential application for treating recalcitrant cases. These cases highlight the rapid progression and challenging management of multidrug-resistant P aeruginosa. Two patients were treated with RB-PDAT as an adjuvant to antibiotic therapy and had improved visual outcomes. Conclusions and Relevance: This case series highlights the concerning progression in resistance and virulence of P aeruginosa and emphasizes the need to explore alternative therapies like RB-PDAT that have broad coverage and no known antibiotic resistance. The findings support further investigation into the potential effects of RB-PDAT for other multidrug-resistant microbes.

Variations in irradiation energy and rose bengal concentration for photodynamic antimicrobial therapy of fungal keratitis isolates.

The purpose is to assess the efficacy of rose bengal photodynamic antimicrobial therapy (PDAT) using different irradiation energy levels and photosensitizer concentrations for the inhibition of fungal keratitis isolates. Seven different fungi (Aspergillus fumigatus, Candida albicans, Curvularia lunata, Fusarium keratoplasticum, Fusarium solani, Paecilomyces variotii, and Pseudallescheria boydii) were isolated from patients with confirmed infectious keratitis. Experiments were performed in triplicate with suspensions of each fungus exposed to different PDAT parameters including a control, green light exposure of 5.4 J/cm2, 2.7 J/cm2 (continuous and pulsed), and 1.8 J/cm2 and rose bengal concentrations of 0.1%, 0.05%, and 0.01%. Plates were photographed 72 h after experimentation, and analysis was performed to assess fungal growth inhibition. PDAT using 5.4 J/cm2 of irradiation and 0.1% rose bengal completely inhibited growth of five of the seven fungal species. Candida albicans and Fusarium keratoplasticum were the most susceptible organisms, with growth inhibited with the lowest fluence and minimum rose bengal concentration. Fusarium solani, Pseudallescheria boydii, and Paecilomyces variotii were inhibited by lower light exposures and photosensitizer concentrations. Aspergillus fumigatus and Curvularia lunata were not inhibited by any PDAT parameters tested. Continuous and pulsed irradiation using 2.7 J/cm2 produced similar results. Rose bengal PDAT successfully inhibits the in vitro growth of five fungi known to cause infectious keratitis. Differences in growth inhibition of the various fungi to multiple PDAT parameters suggest that susceptibilities to PDAT are unique among fungal species. These findings support modifying PDAT parameters based on the infectious etiology.

Phylogenetic and Recombination Analysis of Clinical Vitreous Humor-Derived Adenovirus Isolates Reveals Discordance Between Serotype and Phylogeny.

Purpose: To sequence, identify, and perform phylogenetic and recombination analysis on three clinical adenovirus samples taken from the vitreous humor at the Bascom Palmer Eye Institute. Methods: The PacBio Sequel II was used to sequence the genomes of the three clinical adenovirus isolates. To identify the isolates, a full genome-based multiple sequence alignment (MSA) of 722 mastadenoviruses was generated using multiple alignment using fast Fourier transform (MAFFT). MAFFT was also used to generate genome-based human adenovirus B (HAdV-B) MSAs, as well as HAdV-B fiber, hexon, and penton protein-based MSAs. To examine recombination within HAdV-B, RF-Net 2 and Bootscan software programs were used. Results: In the course of classifying three new atypical ocular adenovirus samples, taken from the vitreous humor, we found that all three isolates were HAdV-B species. The three Bascom Palmer HAdV-B genomes were then combined with over 300 HAdV-B genome sequences, including nine ocular HAdV-B genome sequences. Attempts to categorize the penton, hexon, and fiber serotypes using phylogeny of the three Bascom Palmer samples were inconclusive due to incongruence between serotype and phylogeny in the dataset. Recombination analysis using a subset of HAdV-B strains to generate a hybridization network detected recombination between nonhuman primate and human-derived strains, recombination between one HAdV-B strain and the HAdV-E outgroup, and limited recombination between the B1 and B2 clades. Conclusions: The discordance between serotype and phylogeny detected in this study suggests that the current classification system does not accurately describe the natural history and phylogenetic relationships among adenoviruses.

OUTCOMES OF INFECTIOUS PANUVEITIS ASSOCIATED WITH SIMULTANEOUS MULTI-POSITIVE OCULAR FLUID POLYMERASE CHAIN REACTION.

PURPOSE: To evaluate features of infectious panuveitis associated with multiple pathogens detected by ocular fluid sampling. METHODS: Single-center, retrospective, consecutive case series of patients with aqueous/vitreous polymerase chain reaction testing with >1 positive result in a single sample from 2001 to 2021. RESULTS: Of 1,588 polymerase chain reaction samples, 28 (1.76%) were positive for two pathogens. Most common pathogens were cytomegalovirus (n = 16, 57.1%) and Epstein-Barr virus (n = 13, 46.4%), followed by varicella zoster virus (n = 8, 28.6%), Toxoplasma gondii (n = 6, 21.4%), herpes simplex virus 2 (n = 6, 21.4%), herpes simplex virus 1 (n = 6, 21.4%), and Toxocara (n = 1, 3.6%). Mean initial and final visual acuity (logarithm of the minimum angle of resolution) were 1.3 ± 0.9 (Snellen ∼20/400) and 1.3 ± 1.1 (Snellen ∼20/400), respectively. Cytomegalovirus-positive eyes (n = 16, 61.5%) had a mean final visual acuity of 0.94 ± 1.1 (Snellen ∼20/175), whereas cytomegalovirus-negative eyes (n = 10, 38%) had a final visual acuity of 1.82 ± 1.0 (Snellen ∼20/1,320) ( P < 0.05). Main clinical features included intraocular inflammation (100%), retinal whitening (84.6%), immunosuppression (65.4%), retinal hemorrhage (38.5%), and retinal detachment (34.6%). CONCLUSION: Cytomegalovirus or Epstein-Barr virus were common unique pathogens identified in multi-PCR-positive samples. Most patients with co-infection were immunosuppressed with a high rate of retinal detachment and poor final visual acuity. Cytomegalovirus-positive eyes had better visual outcomes compared with cytomegalovirus-negative eyes.

Role of Topical 5-Fluorouracil in Demodex-Associated Blepharitis.

PURPOSE: The aim of this study was to report clinical observations suggesting the efficacy of topical 1% 5-fluorouracil (5-FU) in treating Demodex-associated blepharitis. METHODS: An observational retrospective review of 13 eyes from 13 individuals with conjunctival neoplastic lesions and concomitant Demodex lash infestation that received topical 1% 5-FU eye drops. Patients underwent slit-lamp examination at each follow-up visit. Clinical photographs of the lash line were obtained after treatment initiation. In a subset of patients, lashes were epilated bilaterally and microscopically analyzed for presence of Demodex mites before and after treatment initiation. RESULTS: The mean age of the population was 68 ± 14 years (range: 30-84 years) and 92% were male. In all 13 patients, a marked reduction in cylindrical dandruff was noted in the treated eye by slit-lamp examination after 2 cycles of 5-FU. There was complete resolution of cylindrical dandruff in 10 of 13 treated eyes compared with 0 resolution of cylindrical dandruff in untreated eyes ( P = 0.0001). In the 6 patients who received epilation, the lashes from the treated eye showed no Demodex, whereas lashes from the fellow untreated eye revealed persistent Demodex. CONCLUSIONS: Topical 1% 5-FU shows efficacy in treating Demodex-associated blepharitis. Further studies are indicated to reproduce our findings and evaluate the potential use of 5-FU as a treatment ingredient.

Endophthalmitis caused by Burkholderia cepacia complex (BCC): clinical characteristics, antibiotic susceptibilities, and treatment outcomes.

PURPOSE: To report the clinical characteristics, antibiotic susceptibilities, and review the literature of Burkholderia cepacia complex (BCC) associated endophthalmitis. STUDY DESIGN: Retrospective, observational case series. METHODS: Clinical and microbiology records were reviewed for patients evaluated at the Bascom Palmer Eye Institute and diagnosed wisth culture-confirmed endophthalmitis due to BCC. Antibiotic susceptibility profiles were generated using standard microbiologic protocols via an automated VITEK system. RESULTS: Endophthalmitis associated with BCC was diagnosed in three patients. Infection occurred in the setting of post-penetrating keratoplasty (PKP), glaucoma filtering surgery, and suspected trauma. All isolates demonstrated in vitro susceptibility to ceftazidime and meropenem. Presenting visual acuity (VA) ranged from hand motion to light perception. Initial treatment strategies included intravitreal ceftazidime (2.25 mg/0.1 mL) and vancomycin (1.0 mg/0.1 mL) injections with fortified topical antibiotics in 2 patients, and surgical debridement of a corneoscleral melt with patch graft along with both topical fortified antibiotics oral antibiotics in the third patient. In all 3 patients, there was no VA improvement at last follow-up, as 2 eyes ultimately underwent enucleation and 1 eye exhibited phthisis bulbi at last follow-up. BCC related endophthalmitis was reviewed among 13 reports. Treatment outcomes were generally poor and antibiotic resistance was common. These BCC isolates cases demonstrated broad resistance patterns, with susceptibilities to ceftazidime (58%), ciprofloxacin (53%), and gentamicin (33%). CONCLUSIONS: Endophthalmitis caused by B. cepacia is a rare clinical entity with generally poor visual outcomes despite prompt treatment with appropriate antibiotics.

Phylogenetic and Genomic Characterization of Whole Genome Sequences of Ocular Herpes Simplex Virus Type 1 Isolates Identifies Possible Virulence Determinants in Humans.

Purpose: There are limited data on the prevalence and genetic diversity of herpes simplex virus type 1 (HSV-1) virulence genes in ocular isolates. Here, we sequenced 36 HSV-1 ocular isolates, collected by the Bascom Palmer Eye Institute, a university-based eye hospital, from three different ocular anatomical sites (conjunctiva, cornea, and eyelid) and carried out a genomic and phylogenetic analyses. Methods: The PacBio Sequel II long read platform was used for genome sequencing. Phylogenetic analysis and genomic analysis were performed to help better understand genetic variability among common virulence genes in ocular herpetic disease. Results: A phylogenetic network generated using the genome sequences of the 36 Bascom Palmer ocular isolates, plus 174 additional strains showed that ocular isolates do not group together phylogenetically. Analysis of the thymidine kinase and DNA polymerase protein sequences from the Bascom Palmer isolates showed multiple novel single nucleotide polymorphisms, but only one, BP-K14 encoded a known thymidine kinase acyclovir resistance mutation. An analysis of the multiple sequence alignment comprising the 51 total ocular isolates versus 159 nonocular strains detected several possible single nucleotide polymorphisms in HSV-1 genes that were found significantly more often in the ocular isolates. These genes included UL6, gM, VP19c, VHS, gC, VP11/12, and gG. Conclusions: There does not seem to be a specific genetic feature of viruses causing ocular infection. The identification of novel and common recurrent polymorphisms may help to understand the drivers of herpetic pathogenicity and specific factors that may influence the virulence of ocular disease.

Endophthalmitis caused by Burkholderia cepacia complex (BCC): Clinical characteristics, antibiotic susceptibilities, and treatment outcomes.

Purpose: To report the clinical characteristics, antibiotic susceptibilities, and review the literature of Burkholderia cepacia complex (BCC) associated endophthalmitis. Study design: Retrospective, observational case series. Methods: Clinical and microbiology records were reviewed for patients evaluated at the Bascom Palmer Eye Institute and diagnosed with culture-confirmed endophthalmitis due to BCC. Antibiotic susceptibility profiles were generated using standard microbiologic protocols via an automated VITEK system. Results: Endophthalmitis associated with BCC was diagnosed in three patients. Infection occurred in the setting of post-penetrating keratoplasty (PKP), glaucoma filtering surgery, and suspected trauma. All isolates demonstrated in vitro susceptibility to ceftazidime and meropenem. Presenting visual acuity (VA) ranged from hand motion to light perception. Initial treatment strategies included intravitreal ceftazidime (2.25 mg/0.1 mL) and vancomycin (1.0 mg/0.1mL) injections with fortified topical antibiotics in 2 patients, and surgical debridement of a corneoscleral melt with patch graft along with both topical fortified antibiotics oral antibiotics in the third patient. In all 3 patients, there was no VA improvement at last follow-up, as 2 eyes ultimately underwent enucleation and 1 eye exhibited phthisis bulbi at last follow-up. BCC related endophthalmitis was reviewed among 13 reports. Treatment outcomes were generally poor and antibiotic resistance was common. These BCC isolates cases demonstrated broad resistance patterns, with susceptibilities to ceftazidime (58%), ciprofloxacin (53%), and gentamicin (33%). Conclusions: Endophthalmitis caused by B. cepacia is a rare clinical entity with generally poor visual outcomes despite prompt treatment with appropriate antibiotics.

Multidrug-Resistant Pseudomonas aeruginosa Keratitis Associated With Artificial Tear Use.

This case report describes severe multidrug-resistant Pseudomonas aeruginosa keratitis in a 72-year-old man after EzriCare artificial tear use.

Outcomes of Nontuberculous Mycobacterial Keratitis After Clear Corneal Incision Phacoemulsification Surgery: A Case Series of 6 Eyes in South Florida.

PURPOSE: The purpose of this study was to present the successful management and outcomes in a series of 6 cases of culture-positive nontuberculous mycobacterial keratitis after clear corneal incision phacoemulsification surgery. METHODS: This is a case series of 6 consecutive eyes that presented at the Cornea Division at an academic institution, diagnosed with culture-positive nontuberculous mycobacterial keratitis after phacoemulsification surgery. RESULTS: Six eyes of 5 patients were included. The mean interval from cataract surgery to presentation was 7.7 weeks. All cases presented with intrastromal abscesses adjacent to corneal incisions, and 2 had scleral extension of the infection. Isolated organisms were Mycobacterium abscessus (n = 4), Mycobacterium chelonae (n = 1), and Mycobacterium mucogenicum (n = 1). All cases were treated with topical amikacin 8 mg/mL for 10.5 weeks on average. All cases received either oral clarithromycin at 500 mg twice-daily dosage or oral azithromycin at 500 mg daily. Two patients with scleral abscesses underwent surgical debridement with amniotic membrane grafts. All 6 eyes achieved infection resolution and good visual recovery, with the final visual acuity ranging from 20/20 to 20/60. None of the patients experienced recurrence of infection. CONCLUSIONS: Prompt medical treatment with combined topical and oral therapy can lead to infection resolution and favorable visual recovery. Early surgical intervention can ensure good outcomes in cases of scleral extension.

Rose Bengal Photodynamic Antimicrobial Therapy: A Review of the Intermediate-Term Clinical and Surgical Outcomes.

PURPOSE: To evaluate the intermediate-term clinical outcomes of Rose Bengal Photodynamic Antimicrobial Therapy (RB-PDAT) for infectious keratitis; secondarily, to evaluate the surgical outcomes of individuals who underwent optical keratoplasty after RB-PDAT. DESIGN: Retrospective cohort study. METHOD: A retrospective chart review was performed of 31 eyes from 30 consecutive individuals with infectious keratitis refractory to standard medical therapy who underwent RB-PDAT at the Bascom Palmer Eye Institute between January 2016 and July 2020. Data collected included demographics, risk factors for infectious keratitis, microbiological diagnosis, best spectacle-corrected visual acuity (BCVA), clinical outcomes after RB-PDAT, and complication rates post-keratoplasty. RB-PDAT was performed as described in previous studies. Graft survival was evaluated using Kaplan-Meier curves with log-ranks in individuals who underwent keratoplasty after RB-PDAT. RESULTS: The mean age of the study population was 53 ± 18.0 years. In all, 70% were female; 53.3% self-identified as non-Hispanic White and 43.3% as Hispanic. Mean follow-up time was 28.0 ± 14.4 months. Risk factors included contact lens use (80.6%), history of infectious keratitis (19.3%), and ocular surface disease (16.1%). Cultures were positive for Acanthamoeba (51.6%), Fusarium (12.9%), and Pseudomonas (6.5%). Of the individuals with Acanthamoeba infection, 22.5% were treated with concomitant Miltefosine. Clinical resolution was achieved in 77.4% of patients on average 2.72 ± 1.85 months after RB-PDAT, with 22.5% requiring therapeutic penetrating keratoplasties and 54.8% subsequently requiring optical penetrating keratoplasties. At 2 years, the overall probability of graft survival was 78.7%, and the graft failure rate was 21.3%. CONCLUSION: RB-PDAT is a potential adjunct therapy for infectious keratitis that may reduce the need for a therapeutic penetrating keratoplasty. Patients who undergo keratoplasty after RB-PDAT may have a higher probability of graft survival at 1 year postoperatively.

Acute-onset postoperative endophthalmitis after cataract surgery performed by resident and attending physicians at a university teaching hospital.

PURPOSE: To evaluate acute-onset postoperative endophthalmitis following cataract surgery and to compare rates between resident and attending physician-performed cohorts. SETTING: Bascom Palmer Eye Institute, Miami, Florida. DESIGN: Retrospective chart review. METHODS: Records of patients diagnosed with endophthalmitis within 6 weeks of surgery performed by attending and resident physicians between January 1, 2015, and December 31, 2020, were reviewed. Total cataract volume was obtained from institutional records, and resident case totals were obtained from case logs. Endophthalmitis cases were obtained from billing records and confirmed with chart review. RESULTS: There were 22 cases of endophthalmitis among 32 505 cases (0.068%). Endophthalmitis occurred in 6 of 6447 (0.093%) resident cases and 16 of 26 058 (0.061%) attending cases ( P = .55). The most common bacterial isolates were coagulase-negative Staphylococcus (8/22, 36.3%) and Streptococcus species (3/22, 13.6%), with negative cultures in 10 (10/22, 45.5%). Initial treatment with vitreous tap and injection of intravitreal antibiotics was performed in 21 eyes (21/22, 95.4%) and vitrectomy with intravitreal antibiotic injection in one (1/22, 4.5%). Vitrectomy was performed secondarily in 9 patients (9/22, 40.9%). Corrected distance visual acuity (CDVA) at last follow-up was ≥20/40 in 13 eyes (13/22, 59%) and ≤hand motions in 3 eyes (3/22, 13.6%). CDVA (logMAR mean ± SD) was 1.22 ± 1.16 in resident and 0.49 ± 0.79 in attending cases ( P = .11). CONCLUSIONS: In the current study, acute-onset postoperative endophthalmitis developed infrequently following cataract surgery. The rates and visual outcomes of endophthalmitis were similar in resident and attending cases.

Endophthalmitis Caused by Kocuria Kristinae.

Kocuria is an anaerobic, Gram-positive bacterium, which has been rarely reported to cause endophthalmitis following cataract surgery, intravitreal injections, penetrating ocular trauma, and also secondary to endogenous sources. Visual prognosis is often guarded, with no previous cases reporting a final visual acuity better than 20/60. We describe a young female patient who developed culture-proven Kocuria kristinae endophthalmitis associated with a traumatic scleral rupture. Visual acuity at 2 months of follow-up improved from light perception to 20/50 after treatment with intravitreal antimicrobial therapy and pars plana vitrectomy.

Role of corneal biopsy in the management of infectious keratitis.

PURPOSE OF REVIEW: The aim of this study was to review the existing literature and investigate the role of microbiologic culture and histopathologic examination of corneal biopsies in the management of infectious keratitis. RECENT FINDINGS: Corneal biopsy continues to be a significantly useful tool in the diagnosis and tailored management of infectious keratitis. Several techniques can be employed for tissue collection, handling and processing to optimize diagnostic yield and maximize safety, including emerging femtosecond laser-assisted biopsy. SUMMARY: Corneal opacities represent a significant cause of global blindness, and infectious keratitis is the most common cause. Organism identification in progressive infectious keratitis is essential for proper management. However, microbiological culture alone has a high rate of false-negative results. Records from the Bascom Palmer Eye Institute were retrospectively searched for patients between 1 January 2015, and 31 December 2019, who underwent corneal biopsy, therapeutic keratoplasty or endothelial graft removal for infectious keratitis and had specimens bisected and submitted for evaluation with both microbiologic culture and histopathologic examination. Detection of bacteria, fungus and mycobacteria was not statistically different between culture and histopathology. Microbiology and histopathology are complementary methods for the identification of causative microorganisms in corneal specimens with presumed infectious keratitis.

Brief incubation of corneal grafts in activated platelet rich plasma enhances corneal endothelial cell survival and regeneration.

Corneal transplantation is the most frequent organ transplantation worldwide. Unfortunately, corneal graft failure is common and endothelial decompensation is considered the major cause. Corneal endothelial cells (CECs) lack the capacity to reproduce, and perioperative and postoperative endothelial cell loss remains a significant challenge associated with corneal graft viability. Therefore, strategies to preserve CEC density are critical to extend graft survival. Activated platelet rich plasma (aPRP), a product extracted from autologous blood, has both antioxidant and regenerative properties. aPRP eye drops have shown effectiveness in the treatment of corneal pathologies such as ulcers, dry eye, and burns. Our purpose is to determine the protective and regenerative effect of aPRP on corneal grafts by evaluating aPRP's effect on the survival and proliferation of human CECs. Human corneal grafts were incubated in aPRP for 15 min to assess the activation of the CEC pAkt survival pathway as measured by ELISA. Evaluation of the protective effect of aPRP was made using an apoptotic model, which simulated oxidative stress conditions. Expression of apoptotic markers was measured using ELISA and endothelial cell viability was determined by optical microscopy. The CEC proliferation rate was measured in vitro with Ki-67 staining. Corneal graft gross structure was evaluated by Hematoxylin & Eosin and Masson trichrome staining. Our results indicate that a short incubation of human corneal grafts in aPRP protects CECs from apoptosis by upregulating the pAkt survival pathway and promoting CEC proliferation. Additionally, aPRP incubation does not induce histological changes in the grafts. A brief pre-treatment of human corneal grafts in aPRP may be beneficial for transplant longevity, as it protects CECs from apoptosis by upregulating intracellular survival pathways and promoting proliferation. In addition, this approach appears to be safe and has the potential to improve surgical outcomes following corneal transplantation.

Nocardia keratitis: amikacin nonsusceptibility, risk factors, and treatment outcomes.

PURPOSE: To report the increasing trends in Nocardia keratitis species diversity and in vitro antibiotic susceptibility, to demonstrate contact lens wear as a risk factor, and to report visual acuity outcomes after treatment. METHODS: A retrospective clinical case series was performed at a single academic referral center which identified 26 patients with culture-confirmed Nocardia keratitis between 2014 and 2021. A combination of conventional microbiology and molecular techniques were used to identify isolates. Antibiotic susceptibilities were determined using both commercial and in-house laboratory methods. Microbiology and electronic medical records were used to characterize patients' clinical profiles. RESULTS: Patients' median age was 32.5 years with a 2:1 male to female ratio. Eighty-four percent (n = 21/25) of patients were diagnosed within two weeks of symptom onset. Nocardia amikacinitolerans (n = 11/26) was the most recovered Nocardia isolate among study patients. Sixty-four percent (n = 16/25) of all isolates, including all 11 N. amikacinitolerans isolates, were resistant to amikacin. All isolates were susceptible to trimethoprim sulfamethoxazole. Contact lens wear was the leading identified risk factor (n = 23/26) in this population. Median time to resolution was 44 days (n = 23, range: 3-190 days). Seventy-one percent of patients (n = 15/21) had a final visual acuity of 20/40 or better. CONCLUSION: Amikacin resistant Nocardia isolates were the majority in the current study. Trimethoprim sulfamethoxazole may be the preferred alternative antibiotic treatment based on in vitro susceptibilities. Contact lens wear was the major risk factor for Nocardia keratitis in South Florida. Overall visual acuity treatment outcomes of patients were favorable.

Rose Bengal and Riboflavin Mediated Photodynamic Antimicrobial Therapy Against Selected South Florida Nocardia Keratitis Isolates.

Purpose: To examine and compare the efficacy of in vitro growth inhibition using rose bengal and riboflavin photodynamic antimicrobial therapy (PDAT) for Nocardia keratitis isolates. Methods: Nocardia asteroides complex, Nocardia amikacinitolerans, and Nocardia farcinica species were isolated from patients with confirmed Nocardia keratitis. Isolates were tested against three experimental groups: (1) no photosensitizer/no irradiation, (2) photosensitizer/no irradiation, and (3) photosensitizer/irradiation. Each isolate was prepared in suspension to a concentration of 1.5 × 108 CFU/mL. Bacterial suspensions were mixed with water or prepared 0.1% photosensitizer solution for a final bacterial concentration of 1.5 × 107 CFU/mL. Aliquots of 1 mL were plated on 5% sheep blood agar. Rose bengal and riboflavin PDAT plates were irradiated for 15 minutes with a 525- or 375-nm custom 6-mW/cm2 powered light source for a total fluence of 5.4 J/cm2. All experimental groups were repeated in triplicate. Plates were incubated in a 35°C non-CO2 incubator for 96 hours and photographed. Percent inhibition was evaluated using LabVIEW-based software. Results: All strains of Nocardia tested with 0.1% rose bengal and irradiated for 15 minutes demonstrated statistically significant inhibition of growth (P < 0.05). No other experimental groups displayed any bacterial inhibition. Conclusions: Rose bengal is superior to riboflavin PDAT against selected Nocardia isolates. In vivo testing is warranted to investigate the utility of rose bengal PDAT for severe Nocardia keratitis. Translational Relevance: In vitro results for three clinical strains of Nocardia support the possible use of rose bengal PDAT as a complementary treatment of Nocardia keratitis.

Interactions between staphylococcal enterotoxins A and D and superantigen-like proteins 1 and 5 for predicting methicillin and multidrug resistance profiles among Staphylococcus aureus ocular isolates.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant (MDR) S. aureus strains are well recognized as posing substantial problems in treating ocular infections. S. aureus has a vast array of virulence factors, including superantigens and enterotoxins. Their interactions and ability to signal antibiotics resistance have not been explored. OBJECTIVES: To predict the relationship between superantigens and methicillin and multidrug resistance among S. aureus ocular isolates. METHODS: We used a DNA microarray to characterize the enterotoxin and superantigen gene profiles of 98 S. aureus isolates collected from common ocular sources. The outcomes contained phenotypic and genotypic expressions of MRSA. We also included the MDR status as an outcome, categorized as resistance to three or more drugs, including oxacillin, penicillin, erythromycin, clindamycin, moxifloxacin, tetracycline, trimethoprim-sulfamethoxazole and gentamicin. We identified gene profiles that predicted each outcome through a classification analysis utilizing Random Forest machine learning techniques. FINDINGS: Our machine learning models predicted the outcomes accurately utilizing 67 enterotoxin and superantigen genes. Strong correlates predicting the genotypic expression of MRSA were enterotoxins A, D, J and R and superantigen-like proteins 1, 3, 7 and 10. Among these virulence factors, enterotoxin D and superantigen-like proteins 1, 5 and 10 were also significantly informative for predicting both MDR and MRSA in terms of phenotypic expression. Strong interactions were identified including enterotoxins A (entA) interacting with superantigen-like protein 1 (set6-var1_11), and enterotoxin D (entD) interacting with superantigen-like protein 5 (ssl05/set3_probe 1): MRSA and MDR S. aureus are associated with the presence of both entA and set6-var1_11, or both entD and ssl05/set3_probe 1, while the absence of these genes in pairs indicates non-multidrug-resistant and methicillin-susceptible S. aureus. CONCLUSIONS: MRSA and MDR S. aureus show a different spectrum of ocular pathology than their non-resistant counterparts. When assessing the role of enterotoxins in predicting antibiotics resistance, it is critical to consider both main effects and interactions.

Rose Bengal Photodynamic Antimicrobial Therapy: A Pilot Safety Study.

PURPOSE: To evaluate the in vivo corneal changes after Rose Bengal photodynamic antimicrobial therapy (RB-PDAT) treatment in New Zealand White rabbits. METHODS: Sixteen rabbits were divided into 5 groups. All groups underwent deepithelialization of an 8 mm diameter area in the central cornea. Group 1: balanced salt solution drops only, group 2: 0.2% RB only, group 3: green light exposure (525 nm, 5.4 J/cm2) only, group 4: 0.1% RB-PDAT, and group 5: 0.1% RB-PDAT. All rabbits were followed clinically. Group 5 rabbits were followed using anterior segment optical coherence tomography (AS-OCT) and clinically. On day 35 after initial treatment, 1 rabbit from group 5 was re-exposed to green light (5.4 J/cm2) to evaluate reactivation of the remaining RB dye, and terminal deoxynucleotyl transferase-mediated UTP-biotin-nick-end labeling assay was performed on corneal cryosections. RESULTS: Complete reepithelization was observed, and corneas remained clear after treatment in all groups. In group 5, AS-OCT revealed a cross-linking demarcation line. AS-OCT showed RB fluorescence and collagen cross-linking in all treated eyes of group 5 animals after 5 weeks of treatment. Photobleached RB retention in the corneal stroma was corroborated by fluorescence confocal microscopy on frozen sections. There was no evidence of a sustained cytotoxic effect through terminal deoxynucleotyl transferase-mediated UTP-biotin-nick-end labeling at 5 weeks. CONCLUSIONS: RB-PDAT with 0.1% RB is a safe procedure. There was no difference clinically and on histopathology compared with control groups. In eyes where RB dye is retained in the corneal stroma after 1 month of treatment, oxidative stress is not evidenced at long term.

Endophthalmitis Caused by Streptococcus:Clinical Outcomes and Antimicrobial Susceptibilities 2014-2019.

BACKGROUND AND OBJECTIVE: To report the clinical settings, antibiotic susceptibilities, and outcomes of streptococcal endophthalmitis. PATIENTS AND METHODS: Retrospective case series evaluating culture-positive streptococcal endophthalmitis from January 1, 2014, to December 31, 2019. RESULTS: Thirty-eight eyes met study criteria. The most common clinical setting was post-glaucoma surgery (33.3%, 12/36). The most frequent isolate was Streptococcus viridans (63.2%, 24/38). Isolates were susceptible to vancomycin (100%, 36/36), ceftriaxone (100%, 28/28), and levofloxacin (100%, 36/36). Final best-corrected visual acuity was 20/150 or better in 24.1% (7/29) but 20/200 or worse in 75.9% (22/29). Enucleation was performed in 11.1% (4/36). A subset (n = 11) of cases were evaluated for streptococcal-specific virulence factors: pneumolysin was present in 18.2% (2/11), autolysin in 45.5% (5/11), and hyaluronidase in 54.5% (6/11). Clinical setting, antibacterial susceptibilities, timing of pars plana vitrectomy, and virulence factor presence were not associated with better visual outcome or enucleation rate (P > .05). CONCLUSION: Visual prognosis for streptococcal endophthalmitis is poor despite early and appropriate antibiotic treatment. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:182-189.].