The pathogenesis of contact lens-associated Pseudomonas aeruginosa corneal ulceration. II. An animal model.
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Animals↗
Biomedical subjects
G A Stern
Publications and source records attributed to G A Stern.
The effect of tuftsin in the treatment of experimental Pseudomonas keratitis.
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Animals↗
Iatrogenic peripheral corneal disease.
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Antipyrine↗
The interaction between Pseudomonas aeruginosa and the corneal epithelium. An electron microscopic study.
The interaction between Pseudomonas aeruginosa and the rabbit corneal epithelium during the first hour after inoculation was studied using scanning and transmission electron microscopy. Fifteen minutes after inoculation, adherent bacteria were found on damaged or exposed basal epithelial cells at the edge of an epithelial defect, and this adherence was the result of an interaction between the bacterial and epithelial cell membranes. Thirty minutes after inoculation, the adherent bacteria began to penetrate the epithelial cells by the formation of "pockets" surrounding the organisms, and after an additional 15 minutes the bacteria further penetrated the cells as the pockets began to fill in with cellular material. One hour after inoculation, only rare bacteria were seen on the cell surfaces or within the margins of the epithelial defect. Transmission electron microscopy, however, revealed many intracellular bacteria or bacteria that had migrated between the basal epithelium and corneal stroma. Therefore, it appears that the initiating events in Pseudomonas corneal ulceration involve adherence to the damaged or exposed basal epithelial cells by an interaction between the bacterial and cellular membranes, after which the organisms are engulfed by the epithelial cell and reach the corneal stroma by a process of transcellular migration.
Adhesiveness↗
Chromobacterium violaceum infection of the eye. A report of two cases.
We report what we believe to be the first two known cases of Chromobacterium violaceum infection of the eye. One patient had conjunctivitis as the initial manifestation of an ultimately fatal infection. In the second patient, who suffered from chronic granulomatous disease of childhood, orbital cellulitis developed as part of a disseminated C violaceum infection from which he subsequently recovered. Infections caused by C violaceum may involve the eye and orbit. These infections are frequently fatal, but early recognition and aggressive treatment may result in a higher cure rate.
Bacterial Infections↗
Effect of topical antibiotic solutions on corneal epithelial wound healing.
The eight topical antibiotic solutions that we use most frequently were tested for their effect on corneal epithelial wound healing in the rabbit. Five percent cefazolin sodium and a mixture of neomycin sulfate, polymyxin B sulfate, and gramicidin (Neosporin) had the least effect on epithelial healing rates and quality of healing, 10% sulfacetamide sodium and an artificial tear had intermediate effects, and gentamicin sulfate, tobramycin, and chloramphenicol were the most toxic. No substantial differences were found between gentamicin and the newer aminoglycoside, tobramycin, and the "fortified" preparations of these two drugs did not seem to be more toxic than the 0.3% solutions. Therefore, topical antibiotic solutions vary in their effects on the corneal epithelium, and not all antibiotics should be considered innocuous when used in the treatment of epithelial defects.
Administration, Topical↗
Intrastromal noninflammatory bacterial colonization of a corneal graft.
Progressive branching, needlelike stromal opacities were observed within a corneal transplant. Analysis of the corneal button by light microscopy and transmission electron microscopy disclosed a localized epithelial ingrowth into the stroma at a suture tract accompanied by intrastromal pockets of gram-positive cocci extending across the cornea. No inflammatory reaction was found in the areas of bacterial colonization. To our knowledge, noninflammatory bacterial colonization of the stroma of a corneal transplant has not been previously described.
Aged↗
Variables in McCarey-Kaufman corneal storage. Their effect on corneal graft success.
The results of 297 penetrating keratoplasties performed over a four-year period were reviewed retrospectively and correlated with eyebank data to determine the effect of the following corneal storage variables on corneal graft clarity: (1) donor age; (2) death-to-preservation interval; (3) death-to-surgery interval; and (4) eyebank grading of donor corneal tissue. The death-to-preservation interval (including a group of corneas preserved 12-19 hours after death) and death-to-surgery interval up to four days had no effect on corneal graft success. Transplants performed with corneas from younger donors had a higher likelihood of success than grafts from older donors (less than 35 years vs greater than 35 years, P less than 0.01; less than 50 years vs greater than 50 years, P less than 0.005). Transplants using tissue rated excellent or good by the eyebank were more successful than those using tissue rated fair (P less than 0.005). In both instances, these results were most apparent in patients believed to have a good prognosis for graft success. Thirteen cases (4.3%) of primary donor failure were identified. None of the corneal storage variables studied could be correlated with primary donor failure.
Adolescent↗
Adherence of Pseudomonas aeruginosa to the mouse cornea. Epithelial v stromal adherence.
Adherence of Pseudomonas aeruginosa to the cornea is the first step in the pathogenesis of Pseudomonas corneal ulceration. To determine the roles of epithelial and stromal adherence, a quantitative in vivo model of adherence was developed in the mouse. More than twice as many organisms were recovered from mouse corneas in which two linear abrasions were created compared with corneas totally denuded of epithelium. Scanning electron microscopy demonstrated poor adherence of Pseudomonas to bare stroma, but large numbers of organisms were seen adhering to the injured edge of epithelium. This study supports the concept that corneal trauma predisposes to Pseudomonas corneal ulceration by creating an injured epithelial edge as a site for adherence of the organisms, rather than by exposing areas of bare stroma susceptible to penetration by the organisms.
Adhesiveness↗
Histopathology of meibomian gland dysfunction.
We conducted a histopathologic study of he meibomian glands of seven patients (all men, ranging in age from 58 to 83 years) who had severe or moderately severe meibomian dysfunction and who were undergoing ectropion or entropion repair. Abnormal features included signs of obstruction and dilatation of ducts, enlargement of acini with cystic degeneration and squamous metaplasia, foreign-body reaction and granuloma formation, a mild increase in inflammatory cells, and abnormal keratinization. Demodex organisms were found in both acini and ducts of one patient. These findings were similar to those reported in other entities involving meibomian duct obstruction, probably related to abnormalities of keratinization, plays an important role in the pathogenesis of meibomian gland dysfunction.
Aged↗
Moraxella corneal ulcers: poor response to medical treatment.
Three patients, all chronic alcoholics, had corneal ulcers caused by two Moraxella species. The diagnosis was suspected from the Gram's stain in two cases and confirmed by culture in all three. In spite of aggressive and appropriate medical management, all three cases required surgical intervention. Two patients underwent penetrating keratoplasty for perforation or descemetocele, and one received a conjunctival flap. Moraxella corneal ulcers often do not respond well to medical treatment. As these organisms are highly susceptible to antibiotics in vitro, host factors must play a role in the poor prognosis of these infections.
Alcoholism↗
Primary herpes simplex subepithelial dendritic keratitis.
A 37-year-old man developed an acute follicular conjunctivitis with preauricular lymphadenopathy believed to be epidemic keratoconjunctivitis. On the eighth day of his disease, subepithelial dendritic opacities developed in the cornea which were not typical of either epidemic keratoconjunctivitis or herpetic keratitis. A diagnosis of primary herpes simplex virus infection was established by positive viral culture and a rise in serum antibody titer to herpes simplex virus. Subepithelial dendritic keratitis as a manifestation of herpes simplex infection of the cornea has not been previously described. The lesions seen in this patient were not reproducible in rabbits and we believe they represent an unusual host response to the virus. This form of herpetic keratoconjunctivitis is extremely difficult to differentiate from epidemic keratoconjunctivitis. Corticosteroids should be used with caution in cases that are not completely typical of epidemic keratoconjunctivitis.
Adult↗
The effect of combined gentamicin-corticosteroid treatment on gentamicin-resistant Pseudomonas keratitis.
In an experimental model of Pseudomonas keratitis caused by a gentamicin-resistant strain of Ps aeruginosa, the results of treatment with gentamicin alone and a gentamicin-steroid combination were evaluated. Treatment with steroids did not reduce the amount of corneal inflammation when compared to eyes treated with gentamicin alone. Eyes treated with the gentamicin-steroid combination were, however, infected with a statistically significant greater number of organisms at the end of a 3-day treatment period. Corticosteroids probably should not be used in the treatment of Pseudomonas keratitis during the early period when the antibiotic sensitivities of the organism are not known.
Animals↗
Clostridium perfringens corneal ulcer.
A corneal ulcer caused by Clostridium perfringens developed in a 76-year-old woman with Sjögren's syndrome. Experimental C perfringens keratitis was induced in rabbits by the intrastromal injection of 10(7) organisms. In both our patient and the experimental animals, a bullous lesion overlay the affected area of the cornea. This may be a specific lesion in clostridial infections of the cornea. Clostridium perfringens should be regarded as an opportunistic corneal pathogen, and anaerobic cultures should be performed in all cases of suspected bacterial corneal ulcer.
Aged↗
Combined amphotericin B and rifampin treatment of experimental Candida albicans keratitis.
In a model of experimental Candida albicans keratitis in rabbits, treatment with a combination of amphotericin B and rifampin was compared with treatment with amphotericin B alone. Both modes of therapy substantially reduced the number of organisms in the cornea below the number in untreated control corneas. In the group treated with combined therapy, there were significantly fewer organisms in the cornea after three days of therapy than in the group treated with amphotericin B alone. The results of this study indicate that the treatment of C albicans keratitis in rabbits with combined amphotericin B and rifampin is more effective than treatment with amphotericin B alone.
Amphotericin B↗
Congenital ocular toxoplasmosis. Possible occurrence in siblings.
In two siblings, we saw bilateral macular lesions that were consistent with the diagnosis of congenital toxoplasmosis. Although the congenital nature of this type of infection cannot be proven conclusively, there is considerable evidence that the lesions in our young patients were scars from congenital toxoplasmic retinochoroiditis. To our knowledge, congenital ocular toxoplasmosis in siblings has not previously been reported.
Adolescent↗
Experimental Bacteroides fragilis keratitis.
To determine the corneal pathogenicity of certain anaerobic bacteria, Bacteroides fragilis keratitis was induced in rabbits by the intrastromal inoculation of 10' viable organisms. All eyes inoculated developed central abscesses within 24 hours. Abscesses persisted and became vascularized in two of three eyes that were observed for two weeks, as demonstrated both clinically and histologically. Eyes inoculated superficially with live organisms or intrastromally with solutions of dead organisms did not develop inflammatory lesions. Anaerobically incubated blood agar plates and thioglycollate broth were equally efficient in recovering organisms, although longer incubation times were occasionally necessary to recover organisms from broth cultures. Bacteroides fragilis and other anaerobic bacteria should be considered in the differential diagnosis of bacterial keratitis, and specific methods should be used to recover these organisms.
Abscess↗
In vitro antibiotic synergism against ocular fungal isolates.
A microtiter method for the determination of fungal sensitivities was used to determine the minimal inhibitory and fungicidal concentrations of two antifungal agents, amphotericin B and natamycin, both alone and in combination with four different antibiotics: rifampin, gentamicin, clindamycin, and tetracycline. Synergism was defined as a fourfold or greater reduction in the minimal inhibitory concentration, minimal fungicidal concentration, or both, of the antifungal agent in the presence of antibiotic; antagonism was defined as fourfold or greater increase in the minimal inhibitory concentration, minimal fungicidal concentration, or both. Amphotericin B and rifampin were synergistic against the majority of organisms, but synergism between amphotericin B and other antibiotics was infrequent. Combinations of natamycin and rifampin or of natamycin and gentamicin were synergistic against the majority of Fusarium solani tested. Combinations of amphotericin B and tetracycline were antagonistic against 14% of the organisms.
Amphotericin B↗