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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Uniformly severe corneal infections were produced in guinea pigs by intracorneal injection of about 10 viable Pseudomonas aeruginosa. After a brief lag period, multiplication of bacteria was rapid, reaching geometric means of 280,000 after 24 hr and of 5 million after 48 hr. Within 8 hr after inoculation, polymorphonuclear leukocytes (PMNs) began to infiltrate the anterior two thirds of the stroma. Stromal cells adjacent to the injection site became necrotic and appeared to be engulfed by PMNs. By 14 to 16 hr, an abscess containing a dense aggregate of PMNs and multiplying bacteria developed in the central stroma. By 16 to 24 hr, collagen breakdown was apparent within and around the abscess. Ultrastructural evidence of collagen breakdown included loss of intact collagen fibrils, tactoid formation, and accumulation of amorphous electron-dense material. The area of liquefactive necrosis gradually enlarged, and many corneas perforated after 3 to 4 days. Because the course of infection is highly reproducible, this model should prove useful for many studies of experimental Pseudomonas keratitis.
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PMID:Pathogenesis of experimental Pseudomonas keratitis in the guinea pig: bacteriologic, clinical, and microscopic observations. 10 Apr 68

Two long-term therapy trials with high concentrations of antibiotic were carried out to determine the duration of therapy required to achieve bacteriologic cure of experimental Pseudomonas keratitis in guinea pigs. In the first study, corneas still contained Pseudomonas after 4 days of continual topical therapy with either tobramycin 400 mg/ml, amikacin 250 mg/ml, ticarcillin 400 mg/ml, or carbenicillin 400 mg/ml. In an 11-day trial of topical therapy with tobramycin 20 mg/ml, 34 of 36 corneas grew no Pseudomonas after 6 or more days of therapy. The bacteriologic response to therapy in this model occurred in two phases. About 99.9% or more of the organisms in the cornea were killed in the first 24 hr of therapy. The numbers of bacteria remaining in the cornea declined gradually over the next several days until the corneas were sterile. Optimal antibiotic therapy may include two stages: initial intensive therapy with high concentrations of antibiotic applied frequently to achieve a large rapid decrease in numbers of organisms in the cornea, followed by prolonged, less intensive therapy to eradicate organisms and prevent relapse.
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PMID:Bacteriologic cure of experimental Pseudomonas keratitis. 10 Apr 71

We studied the systemic absorption ot topical tobramycin and amikacin in experimental Pseudomonas keratitis in guinea pigs. After giving two drops of tobramycin 40 mg/ml every 30 minutes for 24 hours to both infected eyes (the corneal epithelium having removed) the mean serum concentration was 1.5 mcg/ml. Treatment of one of the infected eyes with the same strength of tobramycin or amikacin drops did not alter the number of viable bacteria in contralateral eyes treated with saline. Tobramycin 400 mg/ml or amikacin 250 mg/ml however, decreased the number of viable bacteria in the contralateral eyes. We conclude that the therapeutic effect on the contralateral eye was the result of systemic absorption.
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PMID:Therapeutic effect of topical antibiotic on untreated eye in experimental keratitis. 10 87

Quantitative techniques were used to determine the relative concentrations of viable bacteria and polymorphonuclear leukocytes (PMNs) in the corneas of neutropenic and non-neutropenic guinea pigs with experimental bacterial keratitis induced with three strains of Pseudomonas aeruginosa. Neutropenia was produced by whole-body X-irradiation 1 week before infection. Significantly greater numbers of bacteria were present in the cornea of neutropenic animals 48 h after infection than were present in the corneas of non-neutropenic animals. The same was true 24 and 48 h after infecting animals with Staphylococcus aureus. Examination of histological sections showed that fewer PMNs were present in the corneas of infected neutropenic animals than in the corneas of infected non-neutropenic animals. Radiolabeling of PMNs confirmed a significant reduction in PMN concentration in the corneas of infected neutropenic animals. Tears and the corneal epithelium appear to be the most important elements protecting the cornea against local invasion by bacteria. However, once bacterial keratitis is established, PMNs play a role in limiting bacterial multiplication.
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PMID:Experimental bacterial keratitis in neutropenic guinea pigs: polymorphonuclear leukocytes in corneal host defense. 11 62

Antibiotic therapy of experimental Pseudomonas keratitis was evaluated quantitatively by determining numbers of viable bacteria in the cornea of guinea pigs. Topically applied carbenicillin disodium, gentamicin sulfate, and tobramycin sulfate were often significantly more effective than topically applied polymyxin B sulfate. Intramuscular therapy with tobramycin was as effective as topical therapy, and the results exhibited less variability. Topical tobramycin every 30 minutes was significantly more effective than topical therapy every 60 minutes. No combination of antibiotics was significantly better than a single effective drug. The concentration of tobramycin in the aqueous correlated more closely to therapeutic efficacy than did the concentration in the cornea. Although all antibiotics reduced numbers of bacteria in the cornea by more than 99% in the first 24 hours of therapy, none was able to sterilize the cornea in four additional days of continuous therapy. Persistence of organisms despite apparently adequate topical therapy may explain some reported cases of relapse in humans.
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PMID:Antibiotic therapy of experimental Pseudomonas keratitis in guinea pigs. 19 8

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.
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PMID:The limulus lysate test. A rapid test for diagnosis of Pseudomonas keratitis or endophthalmitis. 30 80

A 45-year-old man died of Hogdkin's disease complicated by peritonitis and possible septicemia. His corneas were used for transplant in a 26-year-old man with advanced keratoconus and a 42-year-old man with vascularized central leukoma of old herpetic keratitis. Both recipients developed a fulminating endophthalmitis with Pseudomonas aeruginosa. We believe that the donor corneas, although clinically normal, were heavily infected, with signs of inflammation possibly suppressed by the Hodgkin's disease.
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PMID:Transfer of bacterial infections by donor cornea in penetrating keratoplasty. 37 48

Three cases of perforated Pseudomonas corneal ulcers with scleral extension were treated with keratoplasty and cryotherapy to the remaining cornea and sclera. All three cases showed dramatic improvement. Cryotherapy of Pseudomonas keratitis in guinea pigs has been shown to be effective. Pseudomonas organisms seem to be susceptible to cryotherapy in vivo; there is no effect in vitro. Cryotherapy may prove to be a new tool in the treatment of Pseudomonas keratitis.
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PMID:Cryotherapy of Pseudomonas keratitis and scleritis. 38 51

It has been suggested that corticosteroids plus the effective antibiotics are more beneficial than antibiotics alone in reducing inflammation in infectious keratitis. Topical and subconjunctival corticosteroids as adjuncts to gentamicin therapy were evaluated by microbiological assay and clinical parameters in experimentally induced Pseudomonas keratitis in rabbits. Various strengths of dexamethasone given concurrently or delayed in conjunction with gentamicin therapy were studied. There was no statistically significant difference between combinations and the antibiotics alone in this experimental model.
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PMID:Treatment of Pseudomonas keratitis in the rabbit with antibiotic-steroid combinations. 40 46

Seven Pseudomonas-induced corneal ulcers were associated with the use of four brands of mascara contaminated with P. aeruginosa. In laboratory studies, preservative systems of three of the four brands were inadequate in comparison with a control mascara of known antimicrobial activity. If the corneal epithelium is scratched during the application of mascara, particularly if the applicator is old, the cornea should be treated immediately and the mascara cultured to detect Pseudomonas. The high incidence of recurrent corneal ulceration in cases of Pseudomonas-induced keratitis indicates that initial chemotherapy should be intensive and maintained until the lesion stabilizes.
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PMID:Pseudomonas-induced corneal ulcers associated with contaminated eye mascaras. 40 95


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