Streptococcal keratitis after myopic laser in situ keratomileusis.
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A 24-year-old healthy male underwent uncomplicated laser in situ keratomileusis (LASIK) in left eye. One day after the surgery, he complained of ocular pain and multiple corneal stromal infiltrates had developed in left eye. Immediately, the corneal interface and stromal bed were cleared, and maximal antibiotic treatments with fortified tobramycin (1.2%) and cefazolin (5%) were given topically. The causative organism was identified as 'Streptococcus viridans' both on smear and culture. Two days after antibiotic therapy was initiated, the ocular inflammation and corneal infiltrates had regressed and ocular pain was relieved. One month later, the patient's best corrected visual acuity had returned to 20/20 with -0.75 -1.00 x 10 degrees, however minimal stromal scarring still remained. This case demonstrates that microbial keratitis after LASIK, if treated promptly, does not lead to a permanent reduction in visual acuity. (+info)
Microbiological profile of anterior chamber aspirates following uncomplicated cataract surgery.
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Anterior chamber aspirate cultures were done for 66 patients who underwent either an uncomplicated intracapsular cataract extraction, extracapsular cataract extraction with posterior-chamber intraocular lens implantation, or phacoemulsification with posterior-chamber intraocular lens implantation. The aspirate was obtained at the time of wound closure. The aspirates were immediately transferred to the microbiology laboratory where one drop of the aspirate was placed on a glass slide for gram stain, and the remainder was unequally divided and inoculated into blood agar, chocolate agar and thioglycolate broth. The cultures were incubated at 37 degrees C with 5% CO2 and held for 5 days. Of 66 patients 4 (6%), had smear-positive anterior chamber aspirates. None of the aspirates showed any growth on any of the 3 culture media used. None of the eyes in the study developed endophthalmitis. This study concludes that there is no contamination of the anterior chamber by viable bacteria after cataract surgery, irrespective of the mode of intervention. (+info)
Presumed ocular bartonellosis.
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BACKGROUND: The spectrum of diseases caused by Bartonella henselae continues to expand and ocular involvement during this infection is being diagnosed with increasing frequency. METHODS: The clinical features and visual prognosis for 13 patients with intraocular inflammatory disease and laboratory evidence of bartonellosis were investigated. There were nine patients with neuroretinitis and four with panuveitis with positive antibody titres against B henselae determined by an enzyme immunoassay (IgG exceeding 1:900 and/or IgM exceeding 1:250). RESULTS: Positive IgG levels were found for eight patients and positive IgM levels for five. Despite animal exposure of 10 patients, only two (IgG positive) cases had systemic symptoms consistent with the diagnosis of cat scratch disease. Pathological fluorescein leakage of the optic disc was observed in all affected eyes. At 6 months' follow up, 3/18 (17%) affected eyes had a visual acuity of less than 20/100, owing to optic disc atrophy and cystoid macular oedema. 12 patients (17 eyes) were treated with antibiotics; visual acuity improved two or more Snellen lines for 9/17 (53%) eyes. CONCLUSIONS: The possibility of B henselae infection should be considered in patients with neuroretinitis and panuveitis (especially in cases with associated optic nerve involvement) even in the absence of systemic symptoms typical for cat scratch disease. (+info)
Identification and antibiotic susceptibility of coagulase negative staphylococci isolated in corneal/external infections.
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AIMS: To identify and determine antibiotic susceptibility of coagulase negative staphylococci (CoNS) isolated from patients with chronic blepharitis, purulent conjunctivitis, and suppurative keratitis. METHODS: A retrospective review of all culture positive cases of chronic blepharitis, purulent conjunctivitis, and suppurative keratitis between July 1995 and December 1996 was performed. Cases in which CoNS were the sole isolates were analysed. Species identification was performed by using a commercially available standardised biochemical test system. Antibiotic susceptibility to penicillin, gentamicin, tetracycline, erythromycin, ciprofloxacin, and teicoplanin was determined by agar disc diffusion (Kirby-Bauer method). Teicoplanin resistance was confirmed by agar dilution. RESULTS: 42 Staphylococcus epidermidis, four S warneri, three S capitis, two S hominis, one each of S xylosus, S simulans, S equorum, and S lugdunensis were identified. 37 CoNS were penicillin resistant, 12 gentamicin resistant, 28 tetracycline resistant, 18 erythromycin resistant, four ciprofloxacin resistant, and one teicoplanin resistant (MIC, 32 microg/ml). In total, 16 strains were resistant to three or more antibiotics. CONCLUSION: Species of CoNS apart from S epidermidis may be isolated from patients with corneal and external infection. Antibiotic susceptibility of CoNS is unpredictable and multiresistant strains are common. As a result, antibiotic susceptibility testing should be performed in all cases of clinically significant ocular infections caused by CoNS. (+info)
Use of a low nutrient culture medium for the identification of bacteria causing severe ocular infection.
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A low nutrient culture medium was used to identify the pathogens in four cases of persisting ocular infection. Bacto R2A agar was used in addition to conventional liquid- and solid-phase media to culture pathogenic bacteria from one case of recurrent keratitis, one case of suture-related keratitis with endophthalmitis and two eyes (two patients) with post-operative endophthalmitis. In each case, a pathogen was identified solely with R2A agar after culture for 6 days. Species isolated were Pseudomonas aeruginosa (one), Propionibacterium acnes (two) and Staphylococcus aureus (one). Antibiotic therapy was tailored to conform to the sensitivity of the cultured organism in each case. The use of Bacto R2A low nutrient agar should be considered in culture negative eyes not showing clinical improvement, or for chronic cases where bacteria may have become adapted to more stringent ocular environments. (+info)
AIMS: To describe the clinical course and treatment of Haemophilus influenzae associated scleritis. METHODS: Retrospective case series. RESULTS: Three patients developed scleritis associated with ocular H influenzae infection. Past medical history, review of systems, and laboratory testing for underlying collagen vascular disorders were negative in two patients. One patient had arthritis associated with an antinuclear antibody titre of 1:160 and a Westergren erythrocyte sedimentation rate of 83 mm in the first hour. Each patient had ocular surgery more than 6 months before developing scleritis. Two had cataract extraction and one had strabismus surgery. Nodular abscesses associated with areas of scleral necrosis were present in each case. Culture of these abscesses revealed H influenzae in all patients. Treatments included topical, subconjunctival, and systemic antibiotics. Scleral inflammation resolved and visual acuity improved in each case. CONCLUSION: H influenzae infection may be associated with scleritis. Accurate diagnosis and treatment may preserve ocular integrity and good visual acuity. (+info)
Microbial decontamination of human donor eyes with povidone-iodine: penetration, toxicity, and effectiveness.
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BACKGROUND/AIMS: Povidone-iodine (PVP -I) is applied for microbial decontamination of human eyes donated for transplantation. Concentrations and immersion times vary greatly. The effectiveness and toxicity of PVP-I were assessed for different decontamination protocols. METHODS: Human donor eyes and corneas were immersed in different concentrations (5-100 mg/ml) of PVP-I for different times (2-30 minutes). The penetration of iodine into the corneal tissue was assessed by x ray microanalysis. Microbial contamination was determined by taking cultures of the limbal areas and storage solutions and by incubation of the corneoscleral buttons in antibiotic-free culture medium. Cytotoxicity of PVP-I for corneal fibroblasts in culture was assessed using the MTT assay. RESULTS: Depending on concentration and immersion time iodine was found to penetrate into the epithelium, Bowman's layer, and stroma in amounts equivalent to 2-40 mg/ml PVP-I. The MTT assay demonstrated that 2.5 mg/ml PVP-I caused total damage to fibroblasts in vitro. Rinsing eyes with tap water and subsequent immersion in PVP-I reduced the rate of contamination from 82 out of 106 to 69 out of 106 and 37 out of 106, respectively. Antibiotics in the storage medium further reduced contamination from about 40% to 3%. Microbial contamination was not reduced by increasing the concentration and immersion times beyond 5 mg/ml PVP-I for 2 minutes. CONCLUSION: Immersion of human donor eyes in 5 mg/ml PVP-I solution for 2 minutes significantly reduces microbial contamination of donor corneas without relevant penetration of iodine into the corneal layers. Higher PVP-I concentrations and longer immersion times do not further reduce contamination, whereas the amount of iodine penetrating the corneal layers is elevated above the level cytotoxic for corneal fibroblasts. In view of this, concentrations above 5 mg/ml of PVP-I and immersion periods over 2 minutes are not recommended for reduction of the contamination rate of donor eyes. (+info)
Risk factors for treatment outcome of suspected microbial keratitis. Ofloxacin Study Group.
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BACKGROUND: Primary treatment for suspected microbial keratitis is generally successful. Although risks such as contact lens use are well recognised as causative factors for microbial keratitis, little is known about the risk factors that influence treatment outcome. The present study evaluates the risk factors assessed at diagnosis as prognostic indicators of primary treatment failure. METHODS: Patients were prospectively enrolled in the ofloxacin treatment trial and data concerning symptoms, treatments, past and concurrent eye disease were collected along with the measurement of corneal ulcer size at the slit lamp. All patients were scraped for microbiological investigation, and treated with either ofloxacin (0. 3%) or standard therapy of fortified cefuroxime and gentamicin drops. Treatment success was complete healing of the ulcer with zero dimensions of the epithelial defect within 2 weeks of start of treatment. The important prognostic indicators were selected by comparison among those who failed treatment, had delayed healing, or were culture positive with other patients using univariate and stratified analysis. These were then used in a Poisson model for multiple regression analysis to estimate the relative risk of the main prognostic variables. RESULTS: Of the 118 patients enrolled in the study, 14 were identified as primary treatment failures, 17 had slow healing, and 15 indolent ulcers. There were 49 culture positive patients. The multivariate analysis identified that large culture positive ulcers in patients 60 years or older had 5.5 times the risk of primary treatment failure (p<0.001). Significant predictors of slow healing were previous ocular disease and a positive culture; significant predictors of indolent ulceration were previous ocular disease and steroid use at diagnosis; the main predictor of a culture positive result was ulcer size. CONCLUSIONS: Elderly patients with large ulcers were more likely to be culture positive, fail primary therapy, and require surgical intervention. A positive microbial culture provided prognostic information regardless of the organism isolated. However, this information was of less value for those with small ulcers and for younger patients. (+info)