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[Electron microscopic study of the corneal endothelium in 2 cases of keratitis. Herpetic disciform keratitis. Neuroparalystic keratitis with dry keratitis].

Study of corneal endothelium by scanning and transmission electron microscopy in two cases of corneal disease. In one case of herpetic keratitis with stromal oedema, there is no cellular reaction. The endothelium is damaged with cellular necrosis and nucleus irregularity. Intercellular junctions are abnormal. With TEM it is possible to say that there are two layers of cells on some places with cellular necrosis. In one case of corneal dryness with lesions of corneal anaesthesia the cells are very damaged and a retrocorneal membrane if formed by many layers of cells. The intercellular junctions are almost normal.

Cornea

Pseudomonas aeruginosa keratitis treated with ticarcillin and tobramycin.

A corneal ulcer, infected with Pseudomonas aeruginosa and complicated by conjunctivitis and endophthalmitis, was treated successfully with systemic administration of ticarcillin and topical application of tobramycin. It is unlikely that carbenicillin, to which the organism was much less sensitive, would have attained sufficient tissue levels to control the infection.

Aged

wbp-encoded LPS O-antigen architecture as a prognostic and therapeutic target in Pseudomonas aeruginosa keratitis.

BACKGROUND: Pseudomonas aeruginosa (P. aeruginosa) keratitis can progress rapidly to vision-threatening disease, even with intensive therapy. Virulence-associated genes are key determinants of ocular-surface pathogenesis. We therefore sought to develop a composite wbp-exo genotyping framework for risk stratification and to guide wbp-dependent, LPS-directed, levofloxacin-polymyxin B (LVX-POL) combination therapy for high-risk corneal infections. METHODS: A well-characterised clinical P. aeruginosa keratitis cohort was integrated with whole-genome sequencing. Based on comprehensive virulence-gene identification and annotation, the relationship between strain-level genetic features and clinical prognosis was analysed. The differences between WBP1 strains and WBP2 strains in adhesion, invasion, and biofilm formation in corneal epithelial cells were further evaluated. To establish biological plausibility, wbp genotypes were correlated with LPS O-antigen electrophoretic profiles and in vivo corneal inflammatory phenotypes in murine infection, including the observation of leucocyte recruitment and cytokine responses. To further confirm the key role of wbp gene status and LPS O-antigen in pathogenicity, wbpL knockout and reconstitution strains were constructed. Their appearances in vitro and in vivo were evaluated. Finally, a mechanistic rationale for an LPS-directed LVX-POL regimen was tested in a high-risk WBP1 P. aeruginosa murine keratitis. FINDINGS: Whole-genome sequencing was performed on 46 clinical P. aeruginosa isolates and identified an average of 332 virulence- and fitness-associated genes per strain. The exo and wbp gene families were significantly associated with patient prognosis. A fusion model (AUC = 0.86) outperformed single-gene-family models (EXO: 0.66; WBP: 0.72) for predicting clinical outcomes. Intact wbp cassettes were enriched in poor-outcome isolates, and electrophoretic LPS profiles indicated that WBP1 strains produce highly polymerised O-antigen associated with sustained neutrophil recruitment and cytokine production. Murine experiments further implicated wbp genes in clinical pathogenesis, showing stronger immune responses and higher expression of TLR4, MyD88, TRAF6, p65, p-p65, IL-6, TNF-α, and IL-1β throughout the inflammatory course. After knocking out wbpL gene, the WBP1 strain got stronger in biofilm formation and adhesion but weaker in inflammation and ocular surface survival. In the high-risk WBP1 P. aeruginosa keratitis model, LVX-POL combinations achieved complete ulcer resolution and markedly improved stromal infiltration and hypopyon, outperforming LVX monotherapy. INTERPRETATION: The wbp gene family was identified as a key genetic factor that contributes to the LPS O-antigen structure, inflammatory intensity, bacterial ocular surface survival and poor prognosis in P. aeruginosa keratitis. A WBP1-targeted, LPS-directed LVX-POL regimen was proposed as a mechanistically informed option for high-risk strains. FUNDING: This research was supported by Beijing Public Health High-level Talent Training Program (Phase III-03-14), Prevention and Control of Emerging and Major Infectious Diseases-National Science and Technology Major Project (2026ZD01909300) and Beijing Natural Science Foundation "QiYan" Undergraduate Research Fund (QY26496).

Pseudomonas aeruginosa

Historical observations on herpetic keratitis.

The history of herpetic keratitis is presented. The similarities and differences between dendritic keratitis and herpes labialis are enumerated, with the suggestion that the similarities (in onset, pathology, and clinical course) far outweigh the differences. The principal difference seems to be that the avascalarity of the cornea retards the immunologic responses. Important points in the history of herpetic keratitis include (1) the close association of herpetic disease with malaria around the turn of the century; (2) the relatively benign nature of the disease, in contrast to herpes zoster keratitis; (3) the unfavorable response of the disease to immunosuppressive measures and diseases; (4) the failure of chemotherapy to influence favorably the natural history of the disease; and (5) the increasing visual damage caused by the disease since 1952 when corticosteroids were introduced into ocular therapy. Mention is made of the increasing problem of venereal herpes, with resultant neonatal herpetic keratitis, retinitis, and encephalitis.

Adrenal Cortex Hormones

Experimental disciform edema and necrotizing keratitis in the rabbit.

The development of experimental disciform edema and necrotizing keratitis in the corneas or rabbits following intrastromal inoculation with the RE strain of herpes simplex virus is described. Following an initial episode of conjunctivitis and epithelial keratitis, a mild, centrally localized, stromal edema developed on the fifth day. Stromal edema, opcification, and neovascularization of the cornea reached maximum severity on the seventh to twenty-second day, and began to fade in most eyes thereafter. On the twenty-ninth day most corneas have attained a resolved state characterized by subepithelial granular opacities. Several eyes were observed which developed central necrotizing keratitis. Marked similarities between the animal model and human herpetic stromal keratitis were apparent. Histological observations show that early necrotizing keratitis in the rabbit is characterized by an infiltration of plasma cells and lymphocytes in the limbus, with polymorphonuclear leukocytes, lymphocytes, and macrophages in the central cornea.

Animals

[Considerations on the meta-herpetic keratitis (author's transl)].

The meta-herpetic keratitis is clinically characterized by the occurrence of a parenchymatous keratitis due to iterative herpetic corneal wounds. The rupture of the Bowman membrane which makes such a deep wound possible is performed by an enzyme: collagenase. This parenchymatous keratitis is rarely due to an extension of the viral infection. Most often it has an immunologic origin. It is a disciform keratitis due to a viral allergy, or a polymorphic keratitis connected with a bacterial, often tubercular, origin. In this case, one always notices a characteristic sugar tongs like composite limbic vascularization. Recovery can only be obtained by a specific desensitization.

Antibodies, Bacterial

Photodynamic inactivation in experimental herpetic keratitis.

The effect of photodynamic inactivation on experimental herpes simplex keratitis in rabbits was investigated using neutral red as a photosensitizing dye followed by exposure to light at 425nm. Combined dye application and light exposure early in the disease (two days following infection) reduced to a minimal extent the severity and duration of the acute epithelial infection. The effect on well-established keratitis (three days postinfection) was negligible as evaluated by clinical grading, viral recovery, and histopathological study. In initial experiments, it was found that the dye and light did not have any observable deleterious effect on intact corneas or cause any noticeable delay in healing of injured cornias. Further, when light or dye were utilized alone, neither changed the severity or duration of the keratitis. In vitro treatment of the virus with light and dye destroys its ability to produce experimental keratitis.

Animals

Impact of Contact Lens Use on Clinical Profile and Outcomes of Fungal Keratitis: An 8-Year Retrospective Study.

PURPOSE: To compare clinical characteristics, microbiological profiles, treatment strategies, and outcomes between contact lens-associated (CL) and noncontact lens-associated (non-CL) fungal keratitis. DESIGN: Retrospective, comparative clinical cohort study. METHODS: A review of culture-proven fungal keratitis treated at a tertiary referral center between 2018 and 2025 was conducted. Cases were categorized as CL or non-CL-associated. Demographic, clinical, microbiological, treatment, and outcome data were analyzed and compared between groups. RESULTS: Thirty-seven eyes were included, comprising 16 CL and 21 non-CL cases. CL users presented earlier than non-CL patients (median 7 vs 14 days, P = .007) and had fewer associated ocular risk factors (31% vs 81%, P = .001). Baseline visual acuity and infiltrate size did not differ significantly between groups. Candida species were isolated in 21% cases, Fusarium in 16% and Aspergillus in 8%. Fusarium (19% vs 13%) and Candida (24% vs 19%) infections were slightly more frequent in non-CL cases. Overall, filamentous fungi were the predominant organism group. Topical voriconazole was the most frequently used antifungal agent (78%). All CL-associated cases resolved with medical therapy alone, with a median time to resolution of 38 days (IQR 22-58). In contrast, 76% of non-CL cases resolved medically (median 42 days, IQR 32-76), while 23% required therapeutic keratoplasty (P = .04). Final visual acuity was comparable between groups (logMAR 0.2 vs 0.5, P = .56). CONCLUSION: Contact lens-associated fungal keratitis is characterized by earlier presentation and fewer underlying ocular comorbidities, with favorable outcomes achieved through medical therapy alone. Despite similar microbiological profiles and treatment approaches, noncontact lens-associated fungal keratitis more frequently follows a complicated course requiring surgical intervention.

Humans

The incidence of herpetic keratitis among population.

The author reports of a relatively little known aspects of herpetic keratitis in man, and its incidence among the population. The incidence of primary herpetic keratitis is 1:8,000 to 1:24,000 while for relapsing herpetic keratitis it amounts to 1:1,653. The relationship of incidence between primary and relapsing herpetic keratitis is 1:5 to 1:14. These achievements have their practical values from the clinical and social aspect.

Age Factors

Clinical Outcomes and Genomic Epidemiology of Multidrug-Resistant Methicillin-Resistant Staphylococcus aureus Keratitis.

PURPOSE: To characterize the clinical features, management, antimicrobial resistance patterns, and genomic epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) keratitis at two North American centers. DESIGN: Retrospective interventional case series combined with laboratory investigation PARTICIPANTS: Seventy eyes of 67 patients presenting laboratory-confirmed MRSA keratitis were included METHODS: We performed a multicenter retrospective case series of patients with culture-proven MRSA keratitis treated between 2005 and 2022. Demographic and clinical data were collected. Antimicrobial susceptibility testing was conducted, and multidrug resistance (MDR) was defined as resistance to ≥3 antibiotic classes. A subset of isolates underwent whole-genome sequencing with core genome multilocus sequence typing. Vancomycin susceptibility, heteroresistance screening, and tolerance testing were performed on available isolates. MAIN OUTCOME MEASURES: Antimicrobial susceptibility and multidrug resistance rates, vancomycin phenotypic profiles, MRSA genotypic distribution, and final best-corrected visual acuity RESULTS: Median age was 63.5 years, and 61.4% were female. Ocular surface disease (67.7%) and prior ocular surgery (65.2%) were common. Only 25.4% had significant healthcare exposure in the preceding year. Most isolates (85.7%) were MDR. Fluoroquinolone susceptibility was low (moxifloxacin 19.7%). All isolates were susceptible to vancomycin (MIC₉₀ 2 µg/mL), and no vancomycin-intermediate, heteroresistant, or tolerant phenotypes were identified. Whole genome sequencing (n = 41) demonstrated predominance of clonal complexes 5 (68.3%) and 8 (29.2%). Visual outcomes were poor, with most patients (85.2%) having a final visual acuity worse than 20/60 among those with follow-up. CONCLUSIONS: MRSA keratitis is associated with high rates of multidrug resistance and poor visual outcomes despite guideline-based therapy. Infections were predominantly caused by CC5 MDR strains despite limited recent healthcare exposure. These findings highlight the persistence of highly resistant MRSA lineages in community-associated corneal infection and underscore the need for ongoing antimicrobial surveillance and optimized treatment strategies.

Humans

The limulus lysate test. A rapid test for diagnosis of Pseudomonas keratitis or endophthalmitis.

The limulus amebocyte lysate test has been shown to be a highly sensitive indicator of endotoxin. Our studies showed that as little as 5 ng of endotoxin could be detected in aqueous or vitreous humor in vitro, although 10 microgram endotoxin injected into the aqueous could not be detected. Subsequent studies showed that by diluting the aqueous equally with saline solution, this inhibitory effect could be overcome. Detection of endotoxin elaborated from Pseudomonas aeruginosa was made as early as 24 hours after induced Pseudomonas keratitis or endophthalmitis, whereas staphylococcal-induced keratitis or endophthalmitis gave negative results. Positive cultures using trypticase soy broth or agar slants were observed on all infected animals. Thus, this technique should have ready application for rapid detection of Pseudomonas keratitis or endophthalmitis.

Animals