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To investigate if topical chlorhexidine 0.2%, which is low cost and easy to formulate, is noninferior to topical natamycin 5% for the treatment of filamentous fungal keratitis. Randomized controlled, single-masked, noninferiority clinical trial. Adults attending a tertiary-level ophthalmic hospital in Nepal with filamentous fungal infection confirmed on smear or confocal microscopy. Participants were randomly allocated to receive topical chlorhexidine 0.2% or topical natamycin 5%. Primary analysis (intention-to-treat) was by linear regression, using baseline logarithm of the minimum angle of resolution (logMAR) best spectacle-corrected visual acuity (BSCVA) and treatment arm as prespecified covariates. Mixed fungal-bacterial infections were excluded from the primary analysis but included in secondary analyses and secondary safety-related outcomes. The noninferiority margin was 0.15 logMAR. This trial was registered with ISRCTN, number ISRCTN14332621. The primary outcome measure was BSCVA at 3 months. Secondary outcome measures included perforation or therapeutic penetrating keratoplasty by 90 days. Between June 3, 2019, and November 9, 2020, 354 eligible participants were enrolled and randomly assigned: 178 to chlorhexidine and 176 to natamycin. Primary outcome data were available for 153 and 151 of the chlorhexidine and natamycin groups, respectively. Of these, mixed bacterial-fungal infections were found in 20 cases (12/153 chlorhexidine, 8/151 natamycin) and excluded from the primary analysis. Therefore, 284 patients were assessed for the primary outcome (141 chlorhexidine, 143 natamycin). We did not find evidence to suggest chlorhexidine was noninferior to natamycin and in fact found strong evidence to suggest that natamycin-treated participants had significantly better 3-month BSCVA than chlorhexidine-treated participants, after adjusting for baseline BSCVA (regression coefficient, −0.30; 95% confidence interval [CI], −0.42 to −0.18; P < 0.001). There were more perforations and emergency corneal grafts in the chlorhexidine arm (24/175, 13.7%) than in the natamycin arm (10/173, 5.8%; P = 0.018, mixed infections included), whereas natamycin-treated cases were less likely to perforate or require an emergency corneal graft, after adjusting for baseline ulcer depth (odds ratio, 0.34; 95% CI, 0.15–0.79; P = 0.013). Treatment with natamycin is associated with significantly better visual acuity, with fewer adverse events, compared with treatment with chlorhexidine. Natamycin remains the preferred first-line monotherapy treatment for filamentous fungal keratitis. [ABSTRACT FROM AUTHOR]

Background: Infective keratitis is the most common corneal pathology in developing countries. Updated knowledge is needed for its control and proper management. Methodology: All cases of presumed microbial keratitis that presented in an 18-month period from October 2013 to March 2015 were enrolled. Data collected were demographic profile, risk factors, clinical features, and organisms isolated and their sensitivities. Results: A total of 602 cases of microbial keratitis were enrolled. Mean age of subjects (598 patients) was 47.9 years with 53.8% male. 64.1% worked in agriculture. 38.3% gave history of trauma followed by history of herpetic eye diseases (17.9%) and topical steroid use (14.2%). A total of 473 who were referred came at an average of 21.5 days of symptoms. 14.9% (n=90) of cases were either perforated or impending to perforate at presentation. 69.6% had infiltrate in the visual axis. A total of 516 (85.7%) underwent diagnostic corneal culture. A total of 256 (49.6%) yielded a positive result. Pure bacterial growth was seen in 111 (43.4%), pure fungal growth in 138 (53.9%), and mixed microbial growth was present in 7 (2.7%) cases. Out of 121 bacterial isolates, 95.0% were Gram positive. Streptococcus pneumoniae (45.5%, n=55) was the most common bacterial isolate followed by Staphylococcus aureus (20.6%, n=25). Out of 145 fungal isolates, Aspergillus and Fusarium species were found in equal numbers (n=41, 28.3% each). Over 85% of Gram-positive organisms isolated in the study were sensitive to vancomycin, cefazolin, moxifloxacin, and gatifloxacin. Over 80% of Gram-negative organisms were sensitive to gentamicin, tobramycin, and amikacin. Conclusion: Microbial keratitis and associated risk factors occurring in farmers implies a lack of awareness and prevention programs. Delay in reaching tertiary care is resulting in complicated cases. Training of local health workers for prophylaxis, updated guidelines for treating keratitis, and timely referral to higher centers are all important in a chain to decrease the incidence of microbial keratitis. Key words: microbial keratitis, infective keratitis, corneal ulcer [ABSTRACT FROM AUTHOR]