Microsporidia-Associated Anterior Uveitis After Keratoconjunctivitis.

OBJECTIVE: The aim of this study was to describe the clinical features and management of uveitis associated with microsporidial keratoconjunctivitis (MKC). METHODS: The medical records of clinically diagnosed or microbiologically proven patients with MKC between July 2016 and August 2021 were reviewed. Patients with documented evidence of keratic precipitates (KPs) or anterior chamber cells were analyzed for their demography, clinical features, and treatment. Patients with microsporidial stromal keratitis and herpes simplex virus keratouveitis were excluded from the study. RESULTS: Of the 2212 patients reviewed within the study period 171 of 172 eyes (7.7%) had documented evidence of KPs and/or anterior chamber cells. The patients' mean age was 43.8 ± 13.8 years, and there were more men (n = 120). The mean duration of appearance of KPs was 6.9 ± 5.5 days, and 28% (n = 48 of 171) appeared on the day of presentation. Superficial punctate keratitis was central and diffuse in 48 and 49 patients, respectively. The treatment was either lubricant alone (45.3%; 78 eyes) or combined with topical steroids (54.7%; 94 eyes). The mean duration of the resolution was longer in the "corticosteroid" than "no corticosteroid" group: KPs: 15.3 ± 6.5 days versus 12.3 ± 5.8 days ( P = 0.007) and superficial punctate keratitises: 15.4 ± 9.4 days versus 11.7 ± 6.2 days ( P = 0.01). The presenting visual acuity with a pinhole was 0.26 ± 0.26 (logMAR) and it improved to 0.03 ± 0.07 on resolution ( P < 0.0001, paired t test). CONCLUSIONS: Uveitis after MKC is a self-limiting entity that often resolves without corticosteroid. One must exercise caution in using steroids in the presence of active corneal lesions.

Effect of polymicrobial interactions on antimicrobial resistance: an in vitro analysis in human ocular infections.

Purpose: Investigate the effect of polymicrobial interactions on antimicrobial resistance (AMR) of ocular pathogens in polymicrobial settings, compared with monomicrobial infections. Methods: Polymicrobial interactions were labeled as antagonistic, synergistic or indifferent based on a reduction, an increase or no change, respectively, in antibiotics' MIC by the Vitek 2 compact system, compared with monomicrobial pathogens. Results:Staphylococcus epidermidis showed antagonistic polymicrobial interactions (22.6%); Pseudomonas aeruginosa showed synergistic interactions (62.5%); multidrug-resistant Acinetobacter baumannii showed increased susceptibility to select antibiotics; Serratia ficaria (inherently colistin resistant) became colistin-susceptible in polymicrobial combinations. Conclusion: Both antagonistic and synergistic interactions exist among human pathogens in polymicrobial settings. Gram-positive pathogens had significantly higher antagonistic polymicrobial interactions (increased MICs: 20.4%) compared with Gram-negative ones (synergistic: 59.4%).

Efficacy of voriconazole and amphotericin B in corneal preservative media.

PURPOSE: To evaluate the efficacy of voriconazole and amphotericin B in McCarey-Kaufman (MK) media. METHODS: MK media vials were supplemented with either voriconazole at 1, 2, 20, 50, 100 µg/mL or amphotericin B at 0.5, 1, 2, 10, 20 µg/mL. The standard inoculum of the American Type Culture Collection (ATCC) strain of Candida albicans, Aspergillus flavus, and Fusarium keratinoplasticum was added to the set of vials. The efficacy outcomes were calculated as 'viable fungal colony counts' determined from the samples taken on Days 0 and 4. MK media containing fungal inoculum but without antifungal supplements were used as control. RESULTS: In the voriconazole arm, on Day 4, a reduction in the colony count was observed for Candida albicans (1 µg/mL, 36%; 100 µg/mL, 100%), Aspergillus flavus (1 µg/mL, 53.8%; 100 µg/mL, 80.4%), and Fusarium keratinoplasticum (1 µg/mL, 39.0%; 100 µg/mL, 72.2%). Similarly, in the amphotericin B arm, on Day 4, a reduction in the colony count was observed for Candida albicans (0.5 µg/mL; 99.9%; 20 µg/mL, 100%), Aspergillus flavus (0.5 µg/mL, 65.2%; 20 µg/mL, 84.8%), and Fusarium keratinoplasticum (0.5 µg/mL, 90.1%; 20 µg/mL, 100%). CONCLUSION: Compared to voriconazole, the addition of amphotericin B significantly reduces fungal contamination in MK media.

Sequelae of microsporidial keratoconjunctivitis and its management.

Purpose: : To characterize the sequelae of microsporidia keratoconjunctivitis (MKC) and outline its management. Methods: Retrospective analysis of microbiologically proven MKC returned with persistent disease between January 2015 and December 2019 was done. Demographics, clinical features, management, and outcome were analyzed. Results: Sixteen patients (21 eyes) of 332 treated for MKC returned with the persisting disease. The mean age of 11 males (68.7%), and 5 females was 35.1 ± 12.2 years. Three-quarter of them did not have a known predisposing risk factor and one-quarter of them were referred for chronic conjunctivitis. Past medications included topical antivirals (n = 8) and topical corticosteroid (n = 6). Three predominant presentations were persistent (>3 weeks) superficial punctate keratitis (SPKs, n = 7), sub-epithelial infiltrates (SEIs, n = 13), and uveitis (n = 2). The lesions recurred in eight eyes (SPK and SEI 4 each) after a disease-free interval of 60.4 ± 40.6 days; there were 13 episodes of recurrence. Topical low potent corticosteroids (loteprednol/fluorometholone), and tacrolimus ointment 0.03% were used in 17 (80.9%) and 8 (38%) eyes, respectively, for a mean duration of 44.8 ± 31.6 and 226.8 ± 180.5 days, respectively. At follow-up, 172.3 ± 183.6 days, visual recovery was statistically significant in persistent eyes (BCVA 0.07 ± 0.07 logMAR; P < 0.00001) but, not in recurrent eyes (BCVA 0.16 ± 0.08 logMAR; P = 0.07). Five of 21 eyes were left with residual significant scar. Conclusion: The sequelae of microsporidial keratoconjunctivitis are not uncommon. Topical 0.03% tacrolimus ointment appeared to be an effective corticosteroid-sparing agent for the treatment of SEIs and prevention of recurrence.

Microbiological spectrum of microbial keratitis in patients presenting with nasolacrimal duct obstruction.

PURPOSE: To study the type of bacteria and their antibiotic susceptibility pattern from corneal scrapings of patients with infectious keratitis presenting with concurrent nasolacrimal duct obstruction. METHODS: A retrospective analysis was carried out of patients with microbial keratitis and co-existing nasolacrimal duct obstruction during a 5-year period (January 2012 to December 2016). Antibiotic susceptibility profile data was collected from the microbiology records. RESULTS: The study included 56 (M:F = 33:23; OD:OS = 34:22) eyes. The mean age of patients was 60.2 ± 12.3 years. Microscopic examination of corneal scrapings showed 52% of gram-positive (n = 29/55) and 2% of multiple (>1; n = 1/55) bacteria. Streptococcus pneumoniae (32%, n = 18/56), coagulase-negative Staphylococcus (25%, n = 14/56), and Staphylococcus aureus (11%, n = 6/56) were the most common bacteria. Streptococcus pneumoniae was found to be susceptible to ciprofloxacin (72.2%), ofloxacin (94.4%), gatifloxacin (61.1%), and moxifloxacin (83.3%). CONCLUSION: Corneal infection associated with nasolacrimal duct obstruction is commonly caused by gram-positive-bacteria. Irrigation of nasolacrimal duct should be mandatory test in microbial keratitis. The gram-positive bacteria isolated showed maximum susceptibility to vancomycin and cefazolin. Early treatment by surgery and appropriate medical management is recommended for its control.

Concurrent Microbial Keratitis and Nasolacrimal Duct Obstruction: Concordance, Etiopathogenesis, and Outcome.

PURPOSE: Nasolacrimal duct obstruction (NLDO) is believed to be a risk factor for microbial keratitis (MK). The primary objective of this study was to look at microbiological concordance between corneal scraping and lacrimal sac flora in patients with concurrent MK and NLDO. The secondary objective was to compare microbiological isolates from MK and NLDO, MK alone, NLDO alone, and healthy subjects. METHODS: A prospective comparative study of 146 subjects with standard microbiological analyses was performed between February 2014 and October 2017. RESULTS: Of the 146 subjects, 35 had concurrent MK and NLDO, 35 had MK, 41 had NLDO, and 35 were healthy subjects. Overall, mean age and sex distribution among groups were similar. In the MK and NLDO group, coagulase-negative staphylococci (CNS) were the most common isolates from the corneal scraping (n = 12/35, 34%) and lacrimal sac (n = 10/35, 29%) with 58% concordance. CNS were also the most common isolates from the NLDO group and healthy subjects, fungus being the most common isolate in the MK group. Anatomical success was achieved in 31 patients (89%) after dacryocystorhinostomy (DCR) in the MK and NLDO group. The difference between the number of patients who had successful DCR surgery but failure of medical therapy for MK (1/31) versus those who failed DCR and medical therapy for MK (3/4) was statistically significant (P = 0.002, Fisher exact test). CONCLUSIONS: CNS are the most common organisms in concurrent MK and NLDO (58% concordance), in patients with NLDO alone, and as commensals in healthy subjects. Persistence of NLDO may be responsible for a poorer outcome of MK in a concurrent setting.

Types of organisms and in-vitro susceptibility of bacterial isolates from patients with microbial keratitis: A trend analysis of 8 years.

PURPOSE: To report the distribution and trends of types of organisms and antibiotic susceptibility of the bacterial isolates obtained from patients with microbial keratitis. METHODS: Microbiology records of culture-positive microbial keratitis that underwent a diagnostic corneal scraping and cultures were reviewed. Fungal, bacterial, and parasitic culture results and antibiotic susceptibility profile of bacteria were analyzed and comparisons were made between two halves of the study period (2007-2010 vs. 2011-2014). RESULTS: A total of 3981 corneal scrapings were processed during the 8-year study period. Pathogen was recovered in culture in 1914 (48.1%) samples. Fungi, bacteria, and parasites constituted 38.7%, 60%, and 1.3% of the total isolates, respectively. The common fungal isolates were Aspergillus spp. (224/868, 25.8%) and Fusarium spp. (200/868, 23.0%), while common Gram-positive bacteria were Streptococcus pneumoniae (217/1125, 19.3%) and Staphylococcus aureus (185/1125, 16.4%), and common Gram-negative bacteria was Pseudomonas spp. (99/219, 45.2%). There was no significant difference in proportion of bacterial (P = 0.225) and fungal (P = 0.421) keratitis between the first half and second half of the study period. There was a significant increase in proportion of Gram-positive isolates (P = 0.015) [353/758 (46.6%) vs. 772/1482 (52.1%)] and decrease in proportion of Gram-negative organisms (P = 0.044) [88/758 (11.6%) vs. 131/1482 (8.8%)] in the recent years. In-vitro antibiotic susceptibility testing showed decrease in susceptibility to moxifloxacin for Pseudomonas spp. (P = 0.016) in recent years. CONCLUSION: Prevalence of fungal and bacterial keratitis has remained unchanged over the years. This study shows a significant increase in Gram-positive bacterial infection and decrease in Gram-negative bacterial infection of the cornea in the recent years.

Sol-Gel-Based Titania-Silica Thin Film Overlay for Long Period Fiber Grating-Based Biosensors.

An evanescent wave optical fiber biosensor based on titania-silica-coated long period grating (LPG) is presented. The chemical overlay, which increases the refractive index (RI) sensitivity of the sensor, consists of a sol-gel-based titania-silica thin film, deposited along the sensing portion of the fiber by means of the dip-coating technique. Changing both the sol viscosity and the withdrawal speed during the dip-coating made it possible to adjust the thickness of the film overlay, which is a crucial parameter for the sensor performance. After the functionalization of the fiber surface using a methacrylic acid/methacrylate copolymer, an antibody/antigen (IgG/anti-IgG) assay was carried out to assess the performance of sol-gel based titania-silica-coated LPGs as biosensors. The analyte concentration was determined from the wavelength shift at the end of the binding process and from the initial binding rate. This is the first time that a sol-gel based titania-silica-coated LPG is proposed as an effective and feasible label-free biosensor. The specificity of the sensor was validated by performing the same model assay after spiking anti-IgG into human serum. With this structured LPG, detection limits of the order of tens of micrograms per liter (10(-11) M) are attained.

Is inclusion of Sabouraud dextrose agar essential for the laboratory diagnosis of fungal keratitis?

PURPOSE: To determine whether the inclusion of Sabouraud dextrose agar (SDA) is essential in the diagnosis of fungal keratitis. MATERIALS AND METHODS: Corneal scrapings of 141 patients with microbial keratitis were smeared and cultured. Sheep blood agar (BA), chocolate agar (CA), SDA, non-nutrient agar (NNA) with Escherichia coli overlay, and brain heart infusion broth (BHI) were evaluated for time taken for growth and cost. The media were also evaluated experimentally for rate of growth and time taken for identification. RESULTS: Twenty-six of 39 patients positive for fungus in corneal scrapings by microscopy were culture-positive. Fungus grew on BA in 22/39, on CA in 18/39, on SDA in 17/39, on NNA in 17/39, and on BHI in 13/39 cases. Growth on SDA was higher in ulcers with larger infiltrate (6/18 versus 9/13, P = 0.04). Estimated saving with inclusion of only BA/CA was Rs. 600 per patient. Performance of all media was similar in in vitro experiment although the characteristic spores and color were seen earlier on SDA. CONCLUSION: Fungal keratitis can be reliably confirmed on BA or CA, which support growth of both bacteria and fungus.