严重真菌性角膜炎患者就诊史调查分析

目的　分析真菌性角膜炎延误诊治的原因。方法　对 2 0 0 0年 1～ 12月山东地区 6 9例(6 9只眼 )因严重真菌性角膜炎行穿透性角膜移植术 (penetratingkeratoplasty ,PKP)或眼球摘除术患者的完整资料进行回顾性分析 ,调查内容包括发病原因、就诊时间、检查经过、诊断及治疗情况等 ,分析延误诊治的可能原因。结果　 6 3例行PKP ,6例行眼球摘除术。其中 5 2例角膜植片直径 >8 0mm。农民占就诊患者的 93%。患者就诊的基本程序为村卫生诊所、乡镇医院、县医院及市级以上医院。平均就诊时间为 2 2 9d。 5 4例 (78% )患者曾到县级医院就诊 ,确诊率为 2 4 % ;其中经角膜刮片检查 12例(2 2 % ) ,阳性率为 5 0 %。 30例在市级以上医院就诊 ,确诊率为 6 3% ;其中角膜刮片检查 2 2例 (73% ) ,阳性率为 73%。 35例 (46 % )术前应用抗真菌药物治疗 ,主要为氟康唑。结论　忽视基本诊断技术、缺乏有效眼科抗真菌药物和供体角膜材料、缺少角膜病专业医师是目前真菌性角膜炎延误诊治的主要原因。     

感染性眼病的细菌病原学及药物敏感性分析

目的：分析细菌感染性结膜炎，角膜炎及眼内炎的细菌培养及药物敏感试验结果。方法：对1996-2000年间284例眼病感染物进行细菌培养鉴定，并对培养阳性的细菌进行体外药物敏感试验。结果：284例培养标本中，培养出细菌62株，培养阳性率为21.8%，其中以表皮葡萄球菌为主，占35.4%，铜绿假单胞菌占16.1%，敏感药物为喹诺酮类及丁胺卡那霉素，结论：表皮葡萄球菌，铜绿假单胞菌及微球菌是主要角结膜感染菌，喹诺酮类药物应作为首选药物。     

Infectious keratitis in South Australia: emerging resistance to cephazolin

PURPOSE: To analyze the microbiologic spectrum and patterns of resistance of infectious keratitis in patients treated at a tertiary hospital in South Australia. METHODS: Retrospective review of microbiology laboratory records of all patients with infectious keratitis who had corneal scrapings, from 1998 to 2003. All records were subsequently reviewed for Gram staining and culture results, as well as antibiotic sensitivity and resistance. RESULTS: Positive corneal cultures were obtained in 134 out of 211 patients who had corneal scrapings (63.5%). Coagulase negative Staphylococcus was the commonest pathogen identified (29.8% of positive cultures), followed by Staphylococcus aureus (18.7%), Pseudomonas aeruginosa (12.7%), Moraxella (6.7%), Streptococcus pneumonia (6.0%), and fungal keratitis (5.2%). In 43.3% of culture positive cases, the organisms were also identified in Gram stain, and in all these cases there was a full correlation between the two methods. In vitro sensitivities were highest for gentamicin. Fourteen cases (35%) of coagulase negative Staphylococcus were found to be resistant to cephazolin. No ciprofloxacin resistance was identified in all Pseudomonas isolates tested. CONCLUSIONS: Staphylococcus species continue to be the commonest causative organism for infectious keratitis; however, there is an emerging resistance to cephazolin, which is commonly used as the first-line antibiotic for Gram-positive cocci.     

Analysis of bacterial cultures in infectious keratitis, 1997 to 2004

PURPOSE: To review bacterial culture results in infectious keratitis at a tertiary referral center. DESIGN: Retrospective case series. METHODS: Analysis of Gram stain, bacterial culture, and targeted antibiotic sensitivities of all cases of presumed infectious keratitis at Duke University Eye Center from 1997 to 2004 (n = 453). RESULTS: Cultures were positive in 307 cases (68%); 21% demonstrated polymicrobial growth. Among 388 isolates, 81% were Gram-positive. Gram stain results were available in 334 cases, demonstrating 18% sensitivity and 94% specificity. Antibiotic sensitivities revealed 24% resistance of tested S. aureus isolates to cefazolin, and <5% resistance of tested gram-negative isolates to various antibiotics, with no statistically significant increase from 1997 to 2004. CONCLUSIONS: In this study, the microbial profile has remained stable from 1997 to 2004. Gram stain studies were of poor sensitivity, while culture yields were significantly higher and demonstrated a relatively high polymicrobial infection rate. Increasing antibiotic resistance was not clearly demonstrated.     

Infectious keratitis: correlation between corneal and contact lens cultures.

PURPOSE: This article reports a study of the effectiveness of performing contact lens cultures to identify causative organisms of infectious keratitis in patients using extended-wear soft contact lenses (cosmetic or therapeutic). METHODS: Patients' records from the Ocular Microbiology Laboratory of the Department of Ophthalmology, Paulista School of Medicine, from 1976 to 2000, and data of patients with contact lens-related keratitis in which the contact lens had been cultured were collected and reviewed. RESULTS: One hundred thirteen patients were included. Only soft contact lenses had been cultured and 29.2% of them were therapeutic contact lenses. An overall concordance of 84.0% was found between cultures obtained from corneal scrapings and contact lenses, with a higher rate in fungal keratitis (100%) compared to amebic (80.0%) and bacterial (74.5%) keratitis. In cases of concomitant bacterial growth in cultures of scrapings and contact lenses, the same organism was detected in 97.04%. Most cases of bacterial infection were caused by Pseudomonas spp. Among the discordant cases (16%), a microorganism was more likely to be isolated by contact lens culture (94.4%). CONCLUSION: Contact lens cultures may identify the causative organisms in most cases of contact lens-related keratitis. The clinical relevance of positive contact lens cultures in keratitis with negative corneal cultures needs further investigation.     

Sensitivity and specificity of confocal scan in the diagnosis of infectious keratitis

PURPOSE: To compare the sensitivity and specificity of confocal scan with the results of corneal and/or contact lens case smear and culture in the diagnosis of infectious keratitis. METHODS: This was a diagnostic test study. Confocal scan and corneal and/or contact lens case smear and culture were performed in all patients with a clinical diagnosis of infectious keratitis at Labbafinejad Medical Center from 2004 to 2006. RESULTS: A total of 133 eyes of 133 patients with a mean age of 48.0 +/- 22.6 years (range, 9-83 years) were included in the study. Sixty-nine (51.9%) cases were men, and 64 (48.1%) were women. Twenty-eight cases (21%) were contact lens wearers; history of trauma and previous ocular surgery was present in 21% and 38.3%, respectively. Corneal and/or contact lens case smear and culture were positive in 71 eyes (53.4%), including 40 cases of bacterial, 16 cases of fungal, and 15 cases of acanthamoeba infection. Confocal scan was positive in 50 cases (37.6%), which revealed hyphae-like structures in 27 cases and cyst and/or trophozoite-like structures in 23 cases. The sensitivity and specificity of confocal scans were 100% and 84% for the diagnosis of acanthamoeba keratitis versus 94% and 78% for fungal keratitis, respectively. CONCLUSIONS: In vivo corneal confocal scan is a rapid noninvasive tool for the diagnosis of acanthamoeba and fungal keratitis with high sensitivity and specificity compared with smear and culture. It may also be helpful in excluding fungal or acanthamoeba-like structures in cases with negative bacteriologic results and in early bacterial keratitis before clarification of microbiologic results.     

Risk factors and causative organisms in microbial keratitis

PURPOSE: To establish the risk factors, causative organisms, levels of antibiotic resistance, patient demographics, clinical presentations, and clinical outcomes of microbial keratitis at a tertiary hospital in Australia. METHODS: Patients who had a corneal scraping for culture over a 5-year period were identified through the local microbiology database, and a retrospective audit of their medical records was carried out. Clinical information was gathered from medical records, and smear, culture, and antibiotic resistance results were from the microbiology database. An index of disease severity was calculated for each patient from scores for the magnitude of the epithelial defect and anterior-chamber reaction and the location of the lesion. Associations between risk factors for keratitis and variables such as patient demographics, causative organism and antibiotic resistance, disease severity, and outcome were analyzed by using analysis of variance and chi tests with appropriate correction for multiple comparisons. RESULTS: Two hundred fifty-three cases of microbial keratitis in 231 patients were included. Sixty percent of patients were men, and there was a bimodal distribution in the age of presentation. Common risk factors for keratitis were contact lens wear (53; 22%), ocular surface disease (45; 18%), ocular trauma (41; 16%), and prior ocular surgery (28; 11%). Gram stains were positive in 33%, with a sensitivity of 53% and specificity of 89%. Cultures of corneal scrapings were positive in 65% of cases, and Pseudomonas aeruginosa (44; 17%), coagulase-negative staphylococci (22; 9%), Staphylococcus aureus (19; 8%), and fungi (7; 3%) were commonly recovered. P. aeruginosa was more common than other culture results in contact lens-related cases (55% vs. 0%-23%; P < 0.001), and S. aureus was more common than other culture results in ocular surgery-related cases (29% vs. 0%-21%; P < 0.001). Patients with keratitis related to prior ocular surface disease had more severe keratitis at the time of scraping (P = 0.037). Cultures positive for Fusarium, P. aeruginosa, and other Gram-negative organisms had statistically significantly more severe keratitis at the time of scraping, whereas patients with negative cultures had milder keratitis (P = 0.030). Only 2% of all bacterial isolates were resistant to ciprofloxacin, 20% of Gram-positive isolates were resistant to cephalothin, and no Gram-negative isolates were resistant to gentamicin. CONCLUSIONS: In this series, the most common risk factor for keratitis was contact lens wear and the most commonly isolated organism was P. aeruginosa.     

Infectious keratitis after astigmatic keratotomy in penetrating keratoplasty: review of three cases

PURPOSE: To present 3 cases in 2 patients of infectious keratitis of the astigmatic keratotomy (AK) site in patients who had previous penetrating keratoplasty. METHODS: History, clinical examination, chart review, cultures, and laboratory results were obtained from 2 patients with infectious keratitis within the donor stroma of their graft after an AK was performed. RESULTS: One patient had an early infiltrate of the AK site that was culture negative. This cleared with fortified antibiotics, and the patient had a final visual acuity of 20/30-2. The second patient developed 2 late infections, the first with coagulase negative Staphylococcus and the second infection with Pseudomonas aeruginosa. Both of these infections cleared with fortified antibiotics, and the final visual acuity was 20/25. Neither patient developed a rejection episode from the infections, and both grafts survived. CONCLUSIONS: We report a series of 3 cases of infectious keratitis in 2 patients after AKs in corneal grafts. This, to the best of our knowledge, has not been previously reported. Patients who suffer infectious keratitis after AK in corneal grafts may have good visual outcomes if managed with appropriate antibiotic regimens and closely followed.     

Bilateral acanthamoeba keratitis

PURPOSE: To determine the prevalence and characteristics of binocular involvement among patients with Acanthamoeba keratitis. DESIGN: Retrospective case series. METHODS: Risk factors and outcomes of bilateral infection were explored among consecutive cases of Acanthamoeba keratitis diagnosed at a single institution from 1997 through mid 2007. RESULTS: Fifty eyes were confirmed to have Acanthamoeba keratitis by microbiologic or histopathologic testing; two-thirds occurred during a regional outbreak beginning in 2004. Five (11%) of 45 patients had infection of both eyes, including three with concurrent involvement and two with successive disease of the contralateral cornea. Three binocularly infected patients used soft contact lenses, and two wore rigid gas-permeable lenses. Nine of 10 eyes achieved visual acuity of 20/30 or better after antiamebic therapy. CONCLUSIONS: Bilateral Acanthamoeba keratitis is an infectious complication of contact lens wear. With laboratory confirmation, vision often can be restored with medical therapy.     

Predisposing factors and etiologic diagnosis of ulcerative keratitis

PURPOSE: To determine the predisposing factors, demographic characteristics, and etiology of ulcerative keratitis in a referral center in Bangkok, Thailand. METHODS: The medical records of admitted patients with positive-culture ulcerative keratitis were retrospectively reviewed for demographic data, predisposing factors, and microbial culture results. Predisposing factors were compared between bacterial and fungal keratitis. RESULTS: From January 2001 to December 2004, there were 127 positive-culture ulcerative keratitis cases. The most frequent microbiological diagnosis was bacterial keratitis (76 eyes, 60%), followed by fungal (48 eyes, 38%) and Acanthamoeba keratitis (3 eyes, 2%). The most common organisms isolated were Pseudomonas spp. for bacteria and Fusarium spp. for fungus. Compared with bacterial keratitis, fungal keratitis was more likely to be associated with ocular trauma (odds ratio = 11.20; 95% confidence interval, 3.62-34.66) but less likely to be associated with contact lens wear (odds ratio = 0.02; 95% confidence interval, 0.01-0.08). CONCLUSIONS: In our study, Pseudomonas and Fusarium species are the most common causes of bacterial and fungal keratitis, respectively. Fungal keratitis was more likely than bacterial keratitis to be associated with ocular trauma, whereas fungal keratitis was less likely to be associated with contact lens wear.     

Propionibacterium acnes as a cause of visually significant corneal ulcers

PURPOSE: To report Propionibacterium acnes as a cause of vision-threatening infectious keratitis and to discuss culture isolation and antibiotic treatment. METHODS: Retrospective case series presentation collected from three academic medical centers. RESULTS: Six cases of P. acnes infectious keratitis are presented, all of which were associated with a compromised corneal barrier or environment. All cases were culture-positive on thioglycolate broth; none became positive before 7 days of growth. No other organisms were isolated from any culture, and the growth of P. acnes occurred in some cases despite negative gram stains. CONCLUSION: P. acnes can produce vision-debilitating keratitis when the cornea is compromised. Growth in culture should be monitored for at least 10 days to ensure isolation of this fastidious organism. P. acnes may respond to several different antibiotics that have gram-positive coverage, but it should be treated with vancomycin to enhance clearance of the organism.     

Infectious keratitis with corneal perforation associated with corneal hydrops and contact lens wear in keratoconus.

BACKGROUND: Corneal perforation is an uncommon complication associated with keratoconus. The first cases of infectious keratitis and corneal perforation associated with corneal hydrops and contact lens wear are reported in two keratoconus patients. METHODS: A retrospective chart review and histopathological examination were carried out. RESULTS: Both patients progressed to corneal perforation and emergency penetrating keratoplasty. One patient cultured Fusarium and the second patient Serratia marcesens. Both patients wore contact lenses against medical advice. CONCLUSIONS: The tear in Descement's membrane, stromal oedema, and epithelial bedewing associated with corneal hydrops results in loss of the epithelial-endothelial barrier of the cornea, creating a conduit for infectious organisms through the cornea. Acute hydrops associated with epithelial keratitis, stromal swelling, and a Descement's membrane tear may be a significant risk factor for infectious keratitis and corneal perforation. Contact lenses should not be worn during an active corneal hydrops owing to the increased risk for severe infectious keratitis and corneal perforation.     

Mycobacterium chelonae keratitis in a patient with Sjögren's syndrome

PURPOSE: In this report a case of Mycobacterium chelonae keratitis in a patient without any previously described risk factors is described. The only risk factor found was a rheumatoid arthritis related Sjogren's syndrome. METHODS: Case report. RESULTS: A 60-year-old woman was referred to the hospital with an infectious keratitis of the left eye of 3 months duration, unresponsive to empirical therapy with ofloxacin and tobramycin drops. Her medical history included a longstanding rheumatoid arthritis and a secondary ocular surface syndrome. Upon arrival the left eye showed diffuse corneal edema and centrally several large infiltrates with fluffy edges, surrounded by several smaller satellite infiltrates. The cornea was scraped for culture and grew M chelonae and sensitivity testing showed sensitivity to ciprofloxacin, clofazimine, and clarithromycin. Systemically, ciprofloxacin 750 mg and clarithromycin 500 mg twice daily were prescribed orally. Topical therapy consisted of topical erythromycin 10 mg/mL and ofloxacin 3 mg/mL every 2 hours. Treatment was continued for a total of 10 months during which the infiltrates cleared completely, but the central cornea remained scarred. CONCLUSIONS: M chelonae can be a cause of infectious keratitis in patients without known risk factors for rapidly growing mycobacterium keratitis. Especially in the case of ocular infections that show no response to regular antibacterial treatment, mycobacterial infection should be considered. Good communication between the ophthalmologist and the microbiologist is crucial for a rapid diagnosis.     

Microbiological study of disposable soft contact lenses after photorefractive keratectomy.

PURPOSE: To evaluate the bacterial contamination of bandage disposable soft contact lenses used in patients following photorefractive keratectomy (PRK) and to correlate our findings with clinical data. METHODS: Forty-six patients (81 eyes) underwent PRK. Immediately after each procedure, disposable soft contact lenses were positioned with sterile forceps. After 3 days, the lenses were removed in a sterile manner, placed in sterile Eppendorf pipettes containing 8 mL of enriched brain heart infusion broth, and analyzed for microbial contamination. RESULTS: Seven positive cultures were found: six gram positive cocci (7.4%) and one gram negative bacillus (1.2%). There was no clinical correlation with these findings. CONCLUSION: Isolated microorganisms were similar to those described in the literature as agents of bacterial keratitis and are components of the normal ocular flora. Klebsiela pneumoniae--considered an occasional or transient flora--was the exception. All isolated microorganisms but K. pneumoniae were sensitive to most of the antibiotics tested. Our findings suggest that the risk of infectious keratitis after PRK related to soft contact lens wear for 3 days seems to be low, which may be because lenses were not manipulated by the patient during the wearing period, and the postoperative antibiotic regimen was strictly followed by patients. However, care should be taken to instruct patients in proper lens care practices to reduce the risk of bacterial keratitis in contact lens wear following PRK.     

Clinical response of contact lens-associated fungal keratitis to topical fluoroquinolone therapy

PURPOSE: To report 5 cases of fungal keratitis associated with contact lens wear that resolved or significantly improved without antifungal therapy. METHODS: Observational case report of 5 patients with a history of contact lens wear who presented with infectious keratitis. Two patients had growth of fungal species on corneal microbiologic cultures, and of the remaining 3 patients, 2 showed fungal elements on confocal microscopy. All 5 patients exhibited growth of fungal species on contact lens microbiologic cultures. All patients received topical fluoroquinolone therapy as initial treatment. RESULTS: In 3 cases, of whom 2 were treated with moxifloxacin 0.5%, the keratomycosis resolved completely on topical fluoroquinolone therapy. One case was switched to topical tobramycin 14 mg/mL and cefazolin 50 mg/mL with complete resolution of the infection. The final case showed marked initial improvement on fluoroquinolone therapy but was subsequently treated with natamycin 5%. CONCLUSIONS: Fungal keratitis associated with soft contact lens wear may occasionally present in a less aggressive form. Topical fluoroquinolone therapy may be an adjunct to the innate immune response in eradicating less fulminant keratomycosis.     

Bilateral bacterial keratitis in three patients following photorefractive keratectomy

PURPOSE: To report clinical manifestations and the bacteriologic profiles of three patients with bilateral bacterial keratitis following photorefractive keratectomy (PRK). METHODS: Photorefractive keratectomy was performed for mild to moderate myopia or compound myopic astigmatism. Bandage contact lenses were fitted at the conclusion of each surgery. Bilateral infectious keratitis was diagnosed within 3 days after surgery. Smear and culture were obtained in all three cases. Patients were treated with topical fortified antibiotics (cefazolin and gentamicin). RESULTS: All patients presented with severe bilateral ocular pain, photophobia, purulent discharge, and dense corneal infiltration. Causative organisms were Staphylococcus aureus (n = 2) and Streptococcus pneumoniae (n = 1). Ulcers were controlled with aggressive medical therapy in five eyes; however, tectonic penetrating keratoplasty was required in one eye. CONCLUSIONS: Uncontrolled blepharitis and bandage contact lens use appears to play a role in the development of bacterial keratitis after PRK. Avoidance of simultaneous bilateral surgery in patients with risk factors for bacterial keratitis, preoperative control of blepharitis, and good contact lens hygiene is suggested.     

Diagnostic Utility of Quantitative Polymerase Chain Reaction versus Culture in Endophthalmitis and Uveitis

Purpose: To compare genetic testing for microbes in infectious endophthalmitis or uveitis to culture.Methods: This was a retrospective, single-center case series that enrolled patients with clinically suspected endophthalmitis or uveitis of unknown etiology. Aqueous humor or vitreous was collected and sent for routine cultures and genetic testing.Results: In total, 46 patients were enrolled. Genetic testing was positive in 32/46 (70%) cases and culture 6/46 cases (13%). Five of 16 uveitis cases had a final clinical diagnosis of infectious uveitis, and polymerase chain reaction (PCR) was positive in 4/5 cases (80%), versus 0% for culture. In uveitis cases, PCR was 80% sensitive and 82% specific, and culture had 0% sensitivity. The overall sensitivity and specificity of PCR for all cases were 85% and 67%, respectively, compared with 17% and 100% for culture.Conclusion: Genetic assays are inexpensive ($25/case) and more sensitive than culture for identifying intraocular pathogens in endophthalmitis and uveitis.     

Fungal keratitis in a daily disposable soft contact lens wearer.

PURPOSE: To report the first case of fungal keratitis in a patient wearing daily disposable soft contact lenses. METHODS: Case Report. A 20-year-old white female in good health developed a corneal ulcer in her lefteye associated with daily disposable soft contact lens wear. There was no history of trauma to the left eye, and she denied overnight wear. Corneal scrapings were taken, and the patient was started on intensive tobramycin 14 mg/mL and cefazolin 50 mg/mL topical therapy for suspected bacterial keratitis. After 3 days of antibacterial therapy, the ulcer worsened. The cultures were negative as were the Gram stain and Gomori's methenamine silver stain. Initial cultures and stains were then repeated with the addition of a culture for herpes simplex virus. The developing clinical picture was suspicious for fungal keratitis. The patient was then started on intensive vancomycin 2%, natamycin 5%, and continued on fortified tobramycin. Three days after the second corneal scrapings were performed, a positive fungal culture was obtained for Fusarium sp. Vancomycin and tobramycin were then discontinued and amphotericin B 0.15% was added to natamycin 5% with the continuation of intensive topical therapy. RESULTS: The patient's keratitis was successfully treated with intensive double antifungal therapy. CONCLUSIONS: Infectious keratitis in daily disposable soft contact lens wear is an unusual occurrence. To our knowledge, there is no previous case of fungal keratitis occurring in patients wearing daily disposable lenses. This case emphasizes the importance of considering fungus in the differential diagnosis for keratitis even in daily disposable contact lens wearers.     

Bacillus megaterium delayed onset lamellar keratitis after LASIK

PURPOSE: To report the history and clinical presentation of a 23-year-old man who developed delayed onset lamellar keratitis in his right eye 2 weeks after uneventful LASIK for correction of myopia. METHODS: Initial clinical presentation suggested an infectious etiology, which led to therapeutic elevation of the LASIK flap and further microbiologic investigation with bacterial cultures. RESULTS: Bacterial cultures revealed Bacillus megaterium, which was sensitive to all antibiotics against which it was tested. Twenty-four hours after initiating aggressive topical and oral antibiotic therapy, symptomatic relief occurred in the affected eye. The patient's uncorrected final visual acuity at 1-year follow-up was 20/15 in the right eye, and the stromal bed developed a faint peripheral non-visually significant scar. CONCLUSIONS: This case is an unusual presentation and course for microbial keratitis following LASIK, which occurred despite aseptic technique and fluoroquinolone antibiotic prophylaxis. Following refractive surgery one should be prepared to culture the lamellar interface in cases of suspected microbial keratitis and begin aggressive antibiotic therapy.