Efficacy of a Novel Antibiotic Drug Combination Toward Multidrug-Resistant Ocular Pathogens.

PURPOSE: Antimicrobial resistance is a global health threat, compounded by the reduction in the discovery of new antibiotics. A repurposed drugs-based approach could provide a viable alternative for the treatment of multidrug-resistant (MDR) bacterial infections. In this study, we sought to evaluate the in vitro efficacy of a novel drug combination, polymyxin B/trimethoprim (PT) + rifampin on MDR isolates from patients with bacterial keratitis in India. METHODS: Forty-three isolates, which included 20 Staphylococcus aureus, 19 Pseudomonas aeruginosa, 3 Pseudomonas stutzeri, and 1 Acinetobacter baumannii, were evaluated for their antibiotic resistance by minimum inhibitory concentration (MIC). Fractional Inhibitory Concentration Index (FICI) testing was performed to measure the antimicrobial impact of PT + rifampin in combination. RESULTS: Among S. aureus isolates, 100% were resistant to at least 1 antibiotic class, 12 (60%) were MDR, and 14 (70%) were classified as methicillin-resistant. Among the gram-negative isolates, >90% were classified as MDR. Fractional Inhibitory Concentration (FIC) testing revealed that PT + rifampin was effective in completely inhibiting growth of all isolates while also displaying additive or synergistic activity in approximately 70% of the strains. Mean FICI values were 0.753 ± 0.311 and 0.791 ± 0.369 for S. aureus and gram-negative isolates, respectively, and a >2-fold reduction in MIC was measured for both PT and rifampin when tested in combination versus alone. CONCLUSIONS: Our data demonstrate the ability of PT + rifampin to eliminate all isolates tested, even those conferring MDR, highlighting the promise of this drug combination for the treatment of bacterial keratitis.

Clinical spectrum in microbiologically proven Demodex blepharokeratoconjunctivitis: An observational study.

PURPOSE: To study the demographic, clinical, and microbiological profile of Demodex-related blepharokeratoconjunctivitis (BKC) at a tertiary eye care hospital. METHODS: This retrospective observational study was conducted from January 2016 to September 2022. It included 83 patients with microbiologically proven Demodex BKC who presented to the cornea department of our tertiary care eye center. The clinical, microbiological, and demographic data of the 83 cases were analyzed. RESULTS: Of the 83 cases, 57 (68.67%) were younger than 40 years, and 25 (30.12%) were below 20. Most patients presented with a good visual acuity of 20/40 or better (93 eyes; 84.55%). The disease was unilateral in 55 patients and bilateral in 28. Cylindrical dandruff was the predominant presentation noted in 61 eyes (54.95%), followed by corneal scarring in 47 eyes (42.34%) and corneal vascularization in 40 eyes (36.04%). On light microscopy, 87.95% of the positive samples were identified as Demodex folliculorum, 7.23% as Demodex brevis, and 6.02% remained unidentified. Tea tree oil and lid scrubs eradicated the disease in most patients clinically (75/83, 90.36%). CONCLUSION: The spectrum of BKC includes both lid signs and corneal involvement. It can be a cause of recurrent BKC and detection of the mite by microscopic evaluation of the lashes can confirm the diagnosis. In most cases, the tea tree oil can effectively manage this condition. However, low doses of topical steroids are needed to control the inflammation in patients with corneal involvement.

Exploring Heparanase Levels in Tears: Insights From Herpes Simplex Virus-1 Keratitis Patients and Animal Studies.

Purpose: Heparanase (HPSE) cleaves heparan sulfate proteoglycans during herpes simplex virus-1 (HSV-1) infection, aiding in viral egress and disease progression. Its action has been well established in in vitro and in vivo models, but its relevance in human patients remains unclear. This study aimed to specifically evaluate tear HPSE levels of patients with herpes simplex keratitis (HSK) and to correlate these findings with a commonly used murine model. Methods: Tear samples from patient and mice samples were collected at LV Prasad Eye Institute, Hyderabad, India, and at the University of Illinois, Chicago, IL, respectively. Tears were collected from HSV-1 patients, bacterial/fungal keratitis cases, and healthy individuals. For in vivo study, C57BL/6 mice were infected with HSV-1 (McKrae strain) followed by tear fluid collection at various time points (0-10 days). Results: The HSV-1, bacterial keratitis, fungal keratitis, and healthy control groups each had 30 patients. There was a significant difference in HPSE expression in the HSV-1 infected eyes (1.55 ± 0.19 units/mL) compared to HSV-1 contralateral eyes (1.23 ± 0.13 units/mL; P = 0.82), bacterial keratitis eyes (0.87 ± 0.15 units/mL; P = 0.0078), fungal keratitis eyes (0.64 ± 0.09 units/mL; P < 0.00001), and normal controls (0.53 ± 0.06 units/mL; P < 0.00001). C57BL/6 mice tear HPSE expression in infected eyes was 0.66 to 5.57 ng heparan sulfate (HS) removed per minute when compared to non-infected eye (range, 0.70-3.67 ng HS removed per minute). Conclusions: To the best of our knowledge, this study is the first to report elevated HPSE levels in the tears of patients with different forms of HSV-1 keratitis, and it confirms similar findings in a murine model, providing a valuable basis for future in vivo and clinical research on HSV-1 ocular infection.

Mesenchymal stem cell-based adjunctive therapy for Pseudomonas aeruginosa-induced keratitis: A proof-of-concept in-vitro.

PURPOSE: Pseudomonas aeruginosa-induced keratitis is one of the most severe and challenging forms of corneal infection, owing to its associated intense inflammatory reactions leading to corneal necrosis and dense corneal scar with loss of vision. Since mesenchymal stem cells (MSCs) are reported to possess antimicrobial and immunomodulatory properties, they can be tested as an adjuvant treatment along with the antibiotics which are the current standard of care. This study aims to investigate the anti-bacterial and immunomodulatory roles of human bone marrow MSC-derived conditioned medium (MSC-CM) in P. aeruginosa-infected human corneal epithelial cells (HCECs) in vitro. METHODS: The effect of MSC-CM on the growth of clinical isolates of P. aeruginosa was evaluated by colony-forming unit assay. The expression of inflammatory cytokines (IL-6 and TNF-α) and an antimicrobial peptide (Lipocalin 2) in lipopolysaccharide-treated MSCs and HCECs was analyzed through ELISA. Corneal epithelial repair following infection with P. aeruginosa was studied through scratch assay. RESULTS: Compared to control (P. aeruginosa (5*105) incubated in DMEM (1 ml) at 37 °C for 16 h), MSC-CM significantly: i) inhibits the growth of P. aeruginosa (159*109 vs. 104*109 CFU/ml), ii) accelerates corneal epithelial repair following infection with P. aeruginosa (9% vs. 24% closure of the wounded area after 12 h of infection), and iii) downregulates the lipopolysaccharide-induced expression of IL-6, TNF-α and Lipocalin 2 in HCECs. A combination of MSC-CM with an antibiotic, Ciprofloxacin moderately regulated the expression of IL-6, TNF-α, and Lipocalin 2. CONCLUSION: MSC-CM holds promise as an adjunctive therapeutic approach for P. aeruginosa-induced corneal epithelial damage.

Antibiotic susceptibility in Endophthalmitis Management Study and intravitreal antibiotic practice trend in India-EMS Report #5.

AIM: Analyze antibiotic susceptibility in the Endophthalmitis Management Study (EMS) and compare it with the current intravitreal antibiotic practice trend of members of the Vitreoretinal Society of India (VRSI) practicing in India. METHODS: The microbiology work-up of undiluted vitreous included microscopy, culture-susceptibility, polymerase chain reaction (PCR), and next-generation sequencing (NGS). VRSI members were invited to the survey. The EMS conventional culture-susceptibility (PCR and NGS excluded) results were compared vis-a-vis gram-positive cocci (GPC), gram-negative bacilli (GNB), and less commonly used antibiotics with the current recommended intravitreal antibiotics. p < 0.05 was considered significant. RESULTS: Culture and positivity (culture + PCR/NGS) positivity was 28.8% and 56.1%, respectively. GPC was most susceptible to cefazolin, linezolid, and vancomycin; GNB was most susceptible to amikacin, ceftazidime, colistin, and imipenem. There was no susceptibility difference between cefazolin and vancomycin (p = 0.999) and between ceftazidime and imipenem (p = 1.0). Colistin was superior to ceftazidime (p = 0.047) against GNB. The GNB resistant to amikacin (n = 14) were equally susceptible to ceftazidime and colistin; resistant to ceftazidime (n = 16) were susceptible to colistin; and resistant to colistin (n = 7) were susceptible to ceftazidime. The preference of VRSI members (n = 231) practicing in India was a vancomycin-ceftazidime combination (82%), vancomycin for GPC (94%), ceftazidime for GNB (61%), and voriconazole for fungi (74%). CONCLUSION: In EMS, GPC had good susceptibility to vancomycin; GNB had good susceptibility to ceftazidime and colistin. Given the lower resistance of colistin, a vancomycin-colistin combination could be an alternative empiric treatment in post-cataract endophthalmitis in India.

Safety and efficacy of McCarey-Kaufman medium supplemented with colistin (polymyxin E) and amphotericin B in inhibiting the multidrug-resistant Pseudomonas aeruginosa using an ex vivo donor corneal infection model.

PURPOSE: This study aimed to evaluate the efficacy and safety of McCarey-Kaufman (MK) medium supplemented with colistin and amphotericin B in inhibiting the growth of multidrug-resistant Pseudomonas (P.) aeruginosa , using an ex vivo experimental model with human donor corneas. METHODS: Cadaveric human corneas deemed unsuitable for corneal transplantation were obtained, and MK media were supplemented with colistin and amphotericin B. Multidrug-resistant P. aeruginosa was cultured and used to infect the human donor corneas ex vivo . Infected corneas were placed in the MK media with additional antibiotics (colistin and amphotericin B) and the standard MK media, which served as the control arm for comparison. Corneal opacity due to infiltration and quantitative analysis of colony-forming units (CFUs) were assessed. The viability of the corneal endothelium was assessed using trypan blue staining. RESULTS: Corneas incubated in MK media supplemented with additional antibiotics showed less corneal opacification compared with those in standard MK media at both 48- and 96-hour (hr) time points. Quantitative analysis revealed a lower bacterial load and a significant reduction in CFU in the corneas incubated in MK media with additional antibiotics compared with the control group. At 48 hrs, there was 84% ( P value = 0.024) reduction in bacterial load, and at 96 hr, a 53% ( P value = 0.016) reduction was observed in comparison with those placed in standard MK media. The trypan blue staining tests revealed that the extent of endothelial cell loss in corneas incubated in supplemented MK media was comparable to the ones in standard MK media. CONCLUSION: The addition of colistin and amphotericin B to MK media demonstrated efficacy in inhibiting the growth of multidrug-resistant P. aeruginosa in an ex vivo cornea infection model. The supplemented media had no detrimental effect on the corneal endothelium. The findings suggest that supplementing the MK media with these broad-spectrum antimicrobial agents may help mitigate the risk of postoperative donor-related infection in the recipients by reducing and containing the load of microbial contamination in donor corneas.

Microbiological Landscape and Epidemiology of Endophthalmitis in Children and Adolescents in a Multi-Tier Ophthalmology Network in India: An Electronic Medical Record-Driven Analytics Report.

PURPOSE: To study the epidemiology and microbiological landscape in patients (≤21 yrs) diagnosed with endophthalmitis across a multi-tier ophthalmology network in India. METHODS: This cross-sectional hospital-based study included 1,041 patients (≤21 yrs) diagnosed with endophthalmitis, between April 2012 and May 2022. The data were collected using an electronic medical record system. RESULTS: Bacteria (24%) was the most common etiology followed by fungus (2%). The majority of the patients were male (66%) with a mean age of 8.37 ± 5.99 years. The most common age group was middle childhood (6-11 years) with 365 (35.06%) patients. The patients were more commonly from the lower socio-economic status (60.81%) and urban geography (49%). The common cause of endophthalmitis was trauma (59.33%) and amongst the 279 culture positive eyes, the predominant bacteria isolated was Streptococcus pneumoniae followed by Bacillus species and fungus included predominantly Aspergillus and Candida species. The most common surgical intervention performed was intraocular antibiotics (74%) followed by pars plana vitrectomy (52%). CONCLUSION: The most common etiology of endophthalmitis in children is bacterial and traumatic in nature and presented from the lower socio-economic status. A half of the eyes warranted a vitreo-retinal surgical intervention. .

A cross-sectional study on the microbiological landscape in pediatric endophthalmitis showed that the most common cause of endophthalmitis was trauma and the predominant bacteria isolated was Streptococcus spp. and Bacillus spp. Additionally, majority of the patients were from the lower socio-economic status and urban geography and the most common surgical intervention performed was injection of intraocular antibiotics.

Evaluating the utility of inflammation score in post-cataract surgery endophthalmitis. Results from a prospective study in India. EMS Report #4.

PURPOSE: To investigate if inflammation score (IS), calculated from the cornea, anterior chamber, iris, and vitreous, indicates endophthalmitis severity. METHODS: In a prospective study, consecutive adults with a clinical diagnosis of post-cataract endophthalmitis within 6 weeks of surgery were recruited. Patients were allocated to IS-based primary treatment (IS < 10: intravitreal injection and IS ≥ 10: vitrectomy) and randomized to two intravitreal antibiotics combinations (vancomycin + ceftazidime and vancomycin + imipenem). Undiluted vitreous microbiology work-up included culture susceptibility, polymerase chain reaction, Sanger sequencing, and targeted next-generation sequencing. RESULTS: The average age of 175 people was 63.4 ± 10.7 years and included 52.6% small incision cataract surgery and 47.4% phacoemulsification surgery. Severe endophthalmitis (IS ≥ 20), diagnosed in 27.4% of people, had a shorter time to symptoms (average 5.4 vs 8.7 days; P = 0.018), poorer presenting vision (all ≤ hand motion), higher culture positivity (50% vs 30.7%; P = 0.032), and higher Gram-negative bacterial infection (70.8% vs 46.2%; P = 0.042). For IS ≥ 20 discriminant and Gram-negative infection, Spearman's coefficient was 0.7 [P < 0.0001, 95% confidence interval (CI) 0.59-0.82], with an area under the receiver operating characteristic curve of 0.9 (95% CI 0.85-0.94, P < 0.0001), a Youden index J of 0.74, a sensitivity of 87.2%, and a specificity of 87.5%. The final vision of >20/400 and >20/100 was regained in 50.2% and 29.1% of people, respectively. The susceptibility of common Gram-positive cocci and Gram-negative bacilli was the highest for vancomycin (95.0%) and colistin (88.6%), respectively. NGS detected polymicrobial infection in 88.5% of culture-negative endophthalmitis. CONCLUSIONS: Higher inflammation scores indicated severe disease and Gram-negative infection in post-cataract endophthalmitis.

Effect of Age on the Etiology and Antibiotic Susceptibility Pattern of Infectious Endophthalmitis.

PURPOSE: To review the etiology and antibiotic susceptibility patterns of infectious endophthalmitis over 11 years in different age groups. METHODS: Microbiology records of culture-positive endophthalmitis cases from January 2011 and December 2021 were reviewed for the age groups 0-30, 31-60, and >60 years. Additionally, data was also analysed for trends in antibiotic susceptibility between different age groups. RESULTS: A total of 5590 patients were clinically diagnosed with endophthalmitis. Of these, 1316 (23.5%) patients were culture positive comprising of 1097 bacteria (83.3%) and 219 fungal (16.6%). Gram-positive bacteria predominated the culture-proven bacterial endophthalmitis group with 709 cases (62.6%). Streptococcus pneumoniae (9.3%) was the most prevalent organism in the age group between 0 and 30 years, while Staphylococcus epidermidis (6%) was the most prevalent organism in the age group of 31-60 years. In comparison, Pseudomonas aeruginosa (4.1%) was the most abundant organism in the age group >60 years. Interestingly, Aspergillus flavus (13.24%) was the predominant fungal pathogen in all age groups. There was an increasing trend in antibiotic resistance from younger to older age groups and this pattern was observed for almost all drugs tested except vancomycin and amikacin. CONCLUSION: While infection can occur at any age, the etiology also seems to vary. This study helps us understand the demography of endophthalmitis along with choice of empirical antibiotics that would influence treatment outcomes. Although vancomycin currently holds good for the treatment for gram-positive infections, gram-negative infections calls for an immediate need for newer drugs or advanced treatment options.

Endophthalmitis Management Study-A Prospective Randomized Clinical Trial on Postoperative Endophthalmitis Management in India: An Interim Analysis. Endophthalmitis Management Study Report #3.

PURPOSE: An interim analysis of the Endophthalmitis Management Study to examine the outcome of inflammation score (IS)-based treatment and antibiotic susceptibility. DESIGN: A prospective randomized study. PATIENTS AND METHODS: IS was measured on a 0-4 scale from presenting signs in 4 cardinal ocular tissues. The eyes with IS <10 received vitreous tap and intravitreal antibiotics, whereas eyes with IS ≥10 received vitrectomy and intravitreal antibiotics. These eyes were randomized to 2 intravitreal antibiotic combinations: (1) vancomycin and ceftazidime and (2) vancomycin and imipenem. Microbiology workup of undiluted vitreous included microscopy, culture-susceptibility, Sanger, and targeted next-generation sequencing. The clinical and microbiology outcomes were analyzed for advanced (IS = ≥20) and less advanced (IS = <10) endophthalmitis. RESULTS: Interim analysis was performed after the Endophthalmitis Management Study recruited 56.85% (248/436) of patients and completed 54.6% (238/436) of microbiology workup. A 90-day follow-up was completed in 90.8% (168/185) of eligible people. In eyes with IS ≥20, the time to symptoms was shorter (5.8 ± 6.7 vs 8.5 ± 9.1 d; P = 0.015), and the need for additional treatment was higher (95.8% vs 53.1%; P = 0.0267). Good final vision was associated with good presenting vision (r = 0.30) and IS-based treatment decisions (r = 0.170). Microbiology positivity was 55.9%. Eyes with IS <10 had a higher Gram-positive cocci (33.9% vs 4.8%; P = 0.013) infection. Gram-positive cocci were most susceptible to vancomycin (95.7%), and Gram-negative bacilli to colistin (95.7%). CONCLUSIONS: Considering both IS and presenting vision, rather than only one of them, helps in making appropriate management decisions for acute postoperative endophthalmitis.

Consensus and controversies in the science of endophthalmitis management: Basic research and clinical perspectives.

Infectious endophthalmitis is a severe intraocular infection caused by bacteria, or less commonly by fungi. It can occur after penetrating eye procedures, trauma, or the spread of infection from contiguous structures or via emboli from distant organs. Because of the time-critical nature of the treatment, endophthalmitis is treated with the clinical diagnosis and modified by the microbiological report of the intraocular contents. The current strategy for managing endophthalmitis relies on pre-clinical literature, case series, and one large multi-center randomized clinical trial on post-cataract surgery endophthalmitis. Culture-susceptibility of the microorganisms from undiluted vitreous guides the definitive treatment in non-responsive cases. Strategies to reduce the incidence of endophthalmitis after penetrating eye procedures have been developed concurrently with refined means of treatment. Despite these advances, outcomes remain poor for many patients. Although consensus articles have been published on managing endophthalmitis, treatment patterns vary, and controversies remain. These include (1) the use of newer methods for early and precise microbiological diagnosis; (2) the choice of intravitreal antibiotics; (3) the need for systemic therapy; (4) early and complete vitrectomy. Here, we review the current consensus and address controversies in diagnosing and managing endophthalmitis. This review is intended to familiarize physicians and ophthalmologists with different aspects of endophthalmitis management to make informed decisions.

Herpes simplex virus keratitis: electronic medical records driven big data analytics report from a tertiary eye institute of South India.

OBJECTIVE: To describe the demographics and clinical profile of Herpes Simplex Virus (HSV) Keratitis in patients presenting to a multi-tier ophthalmology hospital network in South India. METHODS: We have reviewed the medical records of all patients having a clinical diagnosis of any form of HSV keratitis, seen between May 2012 and August 2020 across the L V Prasad Eye Institute network. All the further analyses of the groups were performed using the keywords used for making the diagnosis of HSV keratitis and the data were collected from the electronic medical record system. RESULTS: There were a total of 8308 (N = 8897 eyes) patients. Male: female ratio was 5368 (64.61%):2940 (35.39%). Unilateral involvement was in 7719 (92.91%) patients. The most common age group affected was between the third to fifth decades of life with 1544 (18.58%). 3708 (1.68%) eyes had mild visual impairment (< 20/70) while the rest of them had moderate to severe visual impairment as observed mainly (p ≤ 0.01) in Necrotizing stromal keratitis. 7314 (82.21%) eyes had normal intraocular pressure (10-21 mm Hg) while raised most commonly in keratouveitis (P ≤ 0.01). Epithelial Keratitis, Immune Stromal Keratitis, Endotheliitis, Neurotrophic keratopathy and Keratouveitis were observed in 1875 (17.22%) eyes, 5430 (61.03%) eyes, in 129(1.45%) eyes, 1188 (13.35%) eyes, 148 (1.66%) eyes and 256 (2.88%) eyes respectively. CONCLUSION: Based on our institute-based data, the most common type of HSV keratitis is Immune stromal keratitis followed by epithelial keratitis. Although not representative of the general population, this data provide useful insights related to HSV keratitis from India.

Anti-fungal efficacy of combination of amphotericin B with colistin and gentamicin in McCarey-Kaufman corneal preservation medium.

Purpose: To curtail the potential of donor corneal tissue disseminating fungi to the recipient's eye, we evaluated the addition of amphotericin B to McCarey-Kaufman (M-K)-corneal storage medium supplemented with colistin. Methods: Amphotericin B was examined for its ability to inhibit the growth of Candida albicans and Aspergillus flavus using a microbroth dilution test and checkerboard assay in combination with only gentamicin and a combination of colistin, gentamicin, and amphotericin B. The safety on epithelium and endothelium was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: The minimal inhibitory concentration of gentamicin was found to be >256 µg/ml against both C. albicans and A. flavus, whereas that of amphotericin B was found to be in a range of 0.25-0.5 and 1-2 µg/ml for C. albicans and A. flavus, respectively. According to the checkerboard assay, 80% (4/5) of C. albicans isolates and 100% (5/5) of A. flavus isolates responded synergistically to the combination of amphotericin B and gentamicin, but only 20% (1/5) of C. albicans isolates showed an additive effect. None of the tested isolates displayed antagonism. The combined effect of the three drugs also did not display any antagonistic effect. Additionally, the MTT assay reveals no toxic effect of the antimicrobials used on corneal epithelial and endothelial cells. Conclusion: In vitro experiments demonstrate that amphotericin B is not toxic to either epithelium or endothelium and is a promising additive to the M-K medium supplemented with colistin.

A Novel and Low-cost Approach for Intravitreal Injection in an Experimental Model of Endophthalmitis.

Purpose: Animal models are necessary in understanding the pathogenesis of endophthalmitis and are also necessary to assist the development of new therapeutics for this sight-threatening ocular inflammation. Hamilton syringes are usually preferred to inject pathogens when performing experiments on test subjects, however, this method has technical and financial disadvantages. In this study, we report the findings and assess the related benefits of applying a novel low-cost intravitreal injection technique to initiate endophthalmitis in a mouse model while using the Eppendorf tip and a 26G needle. Methods: The 18-hr culture of clinical isolates of bacteria (Staphylococcus aureus and Pseudomonas aeruginosa) and fungus (Aspergillus flavus and Candida albicans) were resuspended to a final concentration of 10,000 colony forming units (CFU)/1 µL which were separately injected intravitreally into C57BL/6 mice (6-8 weeks) using a 0.1-2.5µL pipette attached to the modified Eppendorf tip with a 26G needle. The contralateral eye served as vehicle/uninjected control. Disease progression was determined by assessing the corneal haze, opacity, bacterial burden, and retinal histology of the eyes used in the model. Following euthanization, bacteria-infected mice were enucleated after 24 hr of the initial injection, and fungus-infected mice after 72 hr. Results: Of the 50 mice injected, the modified technique was successful in 48 mice. Two mice were excluded due to cataract formed by accidental injury to the lens. The experimental endophthalmitis mice model successfully mimicked the natural clinical course. Clinical assessment and histopathology confirmed the influx of inflammatory cells into the posterior segment of the eye along with dissolution of retinal architecture. Conclusion: Our novel method of injection using a modified Eppendorf tip and 26G needle yielded a cost-effective mouse model of clinical endophthalmitis, resulting in reproducible infection for understanding various aspects of its pathobiology.

Microbiological spectrum and antibiotic susceptibility patterns of non-viral conjunctivitis over 16 years at a tertiary eye care center in Southern India.

PURPOSE: To determine the trends in the microbial spectrum and antibacterial susceptibility patterns of non-viral conjunctivitis over 16 years. METHODS: Microbiology data were reviewed from 2006-2021 for all the patients with clinically and culture-proven infectious conjunctivitis. Conjunctival swabs and/or conjunctival scrapings were collected for microbiological workup, and the demographic and antibiotic susceptibility data were extracted from the EMR (Electronic Medical Record). For statistical analysis, χ2-test was performed. RESULTS: Of the 1711 patients, 814 (47.57%) were culture positive and 897 (52.43%) were culture negative. Of the total culture-proven conjunctivitis cases, 775/814 (95.20%) were bacteria, and 39/814 (4.80%) were fungi. Among these bacterial isolates, 75.74% were gram-positive bacteria, while 24.26% were gram negative. The predominant gram-positive pathogens isolated were S. epidermidis (16.7%), S. aureus (17.9%) (p < 0.05), and S. pneumoniae (18.2%), while Haemophilus spp. (36.2%) (p < 0.05) was the most often isolated gram-negative bacteria (36.2%), and Aspergillus spp. was the most commonly isolated fungus (50%). The susceptibility of gram-positive bacteria to cefazoline increased from 90.46 to 98% (p = 0.01), whereas the susceptibility for gatifloxacin decreased in both gram-positive (81-41%; p < 0.0001) and gram-negative bacteria (73-58%; p = 0.02). CONCLUSIONS: Increasing resistance of ocular isolates to mainstay antibiotics is a concern, and this data can assist healthcare practitioners in making informed choices regarding the treatment of ocular infections with ophthalmic antibiotics.

Successful Management of Extensively Drug Resistant Pseudomonas aeruginosa-Infectious Scleritis after Pterygium Surgery.

INTRODUCTION AND PURPOSE: We report a case of extensively drug-resistant (XDR) Pseudomonas aeruginosa (PA) scleritis after pterygium surgery. METHODS: Case report. RESULTS: A 58-year-old farmer presented with a 40-day history of severe pain, swelling, and blurred vision after a pterygium excision was performed at another institute. The patient was on multiple medications with no relief. The examination showed a nasally located scleral thinning in his right eye, with ulceration and infiltrates. Microbiology revealed Pseudomonas aeruginosa, which showed intermediate sensitivity to colistin only. The patient was administered topical (0.19%) and intravenous colistin and dexamethasone. There was a rapid reduction in symptoms, and the lesions healed over the next 2 months. CONCLUSIONS: To the best of our knowledge, this is the first case report of XDR-PA scleritis. We suggest the possibility of evolving drug resistance caused by the iatrogenic use of antibiotics during the early stages of the disease course.

Demystifying Ocular Syphilis - A Major Review.

Syphilis, caused by the spirochaete, Treponema pallidum, continues to be a public health challenge globally with its rates steadily increasing in the past few years. The disease is transmitted through small breaks in the skin during sexual contact, or via congenital transmission in utero, either across the placenta or by contact with an active genital lesion during delivery. Estimated 5.7-6 million new cases are detected every year worldwide in the 15-49 years age group. An increased incidence has been reported in most populations with particular clusters in special groups like men who have sex with men, female sex workers, and their male clients. Ocular syphilis has a varied presentation and is considered a great mimicker in all cases of uveitis. The laboratory diagnosis of syphilis is predominantly based on serological tests including TPHA and VDRL. Parenteral penicillin is the cornerstone of treatment for all stages of ocular syphilis.

Trachipleistophora hominis: molecular characterization of a rare pathogen causing microsporidial stromal keratitis.

The authors report the clinical and microbiological findings of a unique case of stromal keratitis caused by a rare microsporidium, Trachipleistophora hominis. This case of stromal keratitis was in a 49-year-old male with a history of COVID-19 infection and diabetes mellitus. Corneal scraping specimens revealed numerous microsporidia spores upon microscopic examination. PCR of the corneal button revealed the presence of T. hominis infection, which could be controlled by penetrating keratoplasty surgery. The graft was clear with no recurrence of infection until the last follow-up 6 weeks postsurgery. This is the first case of human stromal keratitis caused by this organism in a post-COVID infection, confirmed by molecular diagnosis.

Pediatric Pasteurella canis endophthalmitis.

We report an atypical presentation of endophthalmitis in a 2-month-old infant due to a rare infection by Pasteurella canis, small Gram-negative coccobacilli that inhabit the oral cavity and the gastrointestinal tracts of animals, including domesticated cats and dogs. Ocular infections are mainly associated with animal bites and scratches.