Shifting trends in in vitro antibiotic susceptibilities for common bacterial conjunctival isolates in the last decade at the New York Eye and Ear Infirmary.

BACKGROUND: Bacterial conjunctivitis is one of the most common forms of ocular diseases worldwide. The purpose of this study is to determine the most common pathogens causing bacterial conjunctivitis, their in vitro susceptibility to existing antibiotics, and the changing trends in bacterial resistance to antibiotics over the last decade. METHODS: Records of all conjunctival bacterial cultures performed at the NYEEI Microbiology Laboratory from 1 January 1997 through 30 June 2008 were reviewed. Data on species of bacterial isolates and their in vitro susceptibility to the antibiotics tetracycline, trimethaprim/sulfamethoxazole (TMP/SMZ), imipenem, fluoroquinolones (ciprofloxacin, moxifloxacin, gatifloxacin), aminoglycosides (gentamicin, tobramycin), erythromycin, cefazolin, oxacillin, and vancomycin were collected. RESULTS: Review of records yielded 20,180 conjunctival bacterial cultures, 60.1% of which were culture-positive. Of the culture-positive isolates, 76.6% were gram-positive and 23.4% were gram-negative pathogens. Staphylococcus aureus was the most common gram-positive pathogen isolated, and also the most commonly isolated pathogen overall. Haemophilus influenzae was the most common gram-negative pathogen. A significant increase in the percentage of methicillin-resistant Staphylococcus aureus (MRSA) was observed in the course of 11.5 years. The highest levels of antibiotic resistance were observed to tetracycline, erythromycin, and TMP/SMZ. Gram-positive isolates were least resistant to vancomycin, and gram-negative isolates were least resistant to imipenem. The lowest broad-spectrum antibiotic resistance was observed in the case of moxifloxacin, gatifloxacin, and aminoglycosides. CONCLUSION: Staphylococcus aureus is the most common pathogen in bacterial conjunctivitis. Conjunctival bacterial isolates demonstrated high levels of resistance to tetracycline, erythromycin and TMP/SMZ. Moxifloxacin and gatifloxacin appear to be currently the best choice for empirical broad-spectrum coverage. Vancomycin is the best antibiotic for MRSA coverage.

Incidence and clinical characteristics of enterococcus keratitis.

PURPOSE: To study the incidence, clinically relevant factors, and antibiotic sensitivity profile of cases of enterococcal keratitis presenting at the New York Eye and Ear Infirmary between January 1, 1996, and December 31, 2005. METHODS: The records of all corneal cultures submitted to the Microbiology Laboratory of the New York Eye and Ear Infirmary between January 1, 1996, and December 31, 2005, were reviewed. All cases that were positive for Enterococcus species were identified, and the corresponding patients' medical records were obtained and studied. RESULTS: There were 15 cases of enterococcal keratitis identified during the study period, and all were E. faecalis species. The age of the patients ranged from 17 to 98 years (mean age, 57.5 years). Twelve of the patients were women. Two patients developed keratitis in existing corneal grafts. Two patients were on topical steroid medications, with 1 having an existing corneal graft. Fourteen of the 15 had abnormalities of the ocular surface or wore contact lenses. Eight (53%) of the patients were soft contact lens wearers. Only 1 case was directly attributable to trauma. Fourteen (93%) of the bacterial isolates were sensitive to vancomycin. One case had intermediate sensitivity. Eleven cases resolved with topical antibiotics, 3 cases required penetrating keratoplasty, and in 1 case, the outcome is unknown. CONCLUSIONS: Enterococcus faecalis keratitis is associated with abnormalities of the corneal surface and contact lens wear. Most of the isolates were sensitive to vancomycin, although 1 was of intermediate sensitivity, the importance of which is not known.

Efficacy and safety of voriconazole as an additive in Optisol GS: a preservation medium for corneal donor tissue.

PURPOSE: To assess the endothelial toxicity and the microbiological efficacy of voriconazole (100 microg/mL) as an antimicrobial additive to Optisol GS. METHODS: A total of 533 donor rims were studied. One half of each donor rim was placed in standard Optisol GS and the other half rim in Optisol GS fortified with voriconazole (100 microg/mL). All rims were refrigerated for 24 hours at 3 degrees C and placed in thioglycolate broth and incubated at 37 degrees C for 7 days. A pair of donor buttons not used in transplantation was stored for 2 days in each solution and examined for endothelial changes with electron microscopy (EM). A second pair of cornea buttons was examined for toxicity by endothelial staining with 0.3% trypan blue and 0.2% alizarin red. RESULTS: Seven of 533 corneal rim cultures were positive for fungal organisms in the Optisol GS group. No rims were positive for fungal growth in the voriconazole-fortified Optisol GS medium. The difference was statistically significant (P = 0.015; Fisher exact test). There was no difference in the cellular morphology of the button stored in voriconazole fortified Optisol GS compared with Optisol GS using EM. In the bioassay, the percentage of nonviable cells in the voriconazole-fortified medium compared with the control medium was nonsignificant (P < 0.05, Student t test). CONCLUSIONS: Voriconazole seems to be safe as a fortifying agent for cornea storage medium. It significantly reduces the rate of positive fungal rim cultures and shows no signs of endothelial cytotoxicity as viewed by EM and by a bioassay of trypan blue and alizarin red.

Isolation, purification and cultivation of conjunctival melanocytes.

The purpose of the present study was to develop methods for isolation, purification and cultivation of human conjunctival melanocytes. Conjunctiva excised from donor eyes or corneal rims was subjected with various enzyme digestion methods or by the enzyme-microdissection method. Cells were cultured with F12 medium supplemented by fetal bovine serum, basic fibroblast growth factor, isobutylmethylxanthine and cholera toxin. Contaminant cells were eliminated by a selective cytotoxic agent, geneticin. Both trypsin digestion and dispase-microdissection methods provided pure conjunctival melanocyte cultures with high cell yields, good viability and rapid growth rate. Melanocytes isolated with dispase-microdissection method showed better viability and growth capacity. Cells grew well, could be passaged for 5-10 generations and divided 20 times in vitro. They maintained a constant melanin content per cell and produced measurable amounts of melanin in vitro. Melanogenesis correlated with the degree of pigmentation of the eyes (iris color). This method provides a valuable source of large numbers of human conjunctival melanocytes, which can be used to study their biological behavior, to compare with the epidermal and uveal melanocytes; and to compare them to their malignant counterparts in the exploration of the pathogenesis of conjunctival melanoma.

Molecular characterization, biofilm analysis and experimental biofouling study of Fusarium isolates from recent cases of fungal keratitis in New York State.

BACKGROUND: To characterize Fusarium isolates from recent cases of fungal keratitis in contact lens wearers, and to investigate fungal association with MoistureLoc solution. METHODS: We studied six fungal isolates from recent cases of keratitis in New York State. The isolates were characterized by nucleotide sequencing and phylogenetic analyses of multiple genes, and then typed using minisatellite and microsatellite probes. Experimental fungal biofilm formation was tested by standard methods. MoistureLoc solutions were tested in biofouling studies for their efficacy in elimination of Fusarium contamination. RESULTS: Fusarium solani--corneal ulcers (2 isolates), lens case (1 isolate), and F. oxysporum--corneal ulcer (1 isolate), eye (1 isolate), were recovered from five patients. An opened bottle of MoistureLoc solution provided by a patient also yielded F. solani. Two distinct genotypes of F. solani as well as of F. oxysporum were present in the isolated strains. Remarkably, F. solani strains from the lens case and lens solution in one instance were similar, based on phylogenetic analyses and molecular typing. The solution isolate of F. solani formed biofilm on contact lenses in control conditions, but not when co-incubated with MoistureLoc solution. Both freshly opened and 3-month old MoistureLoc solutions effectively killed F. solani and F. oxysporum, when fungal contamination was simulated under recommended lens treatment regimen (4-hr). However, simulation of inappropriate use (15-60 min) led to the recovery of less than 1% of original inoculum of F. solani or F. oxysporum. CONCLUSION: Temporary survival of F. solani and F. oxysporum in MoistureLoc suggested that improper lens cleaning regimen could be a possible contributing factor in recent infections.

Efficacy and safety of moxifloxacin as an additive in Optisol-GS a preservation medium for corneal donor tissue.

PURPOSE: To assess the endothelial toxicity and the microbiological efficacy of moxifloxacin (250 microg/mL) as an additive to Optisol-GS. METHODS: Five hundred nine donor rims were studied. One half of each donor rim was placed in standard Optisol-GS and the other half of the rim in Optisol-GS fortified with moxifloxacin (250 microg/mL). All rims were refrigerated for 24 hours at 3 degrees C and placed in thioglycolate broth and incubated at 37 degrees C for 7 days. One pair of donor buttons not used in transplantation stored in each solution was examined for endothelial changes by using electron microscopy (EM). A second pair of cornea buttons was examined for toxicity by endothelial staining with 0.3% trypan blue and 0.2% alizarin red. All endothelial cells that stained (nonviable cells) and nonstained cells (viable cells) were counted, and the ratio of nonviable cells was calculated. RESULTS: The rate of culture-positive donor rims in the Optisol-GS group was 11.9% (61/509) and in the moxifloxacin-fortified Optisol-GS media was 2.5% (13/509). The difference was statistically significant (P < 0.01; chi test). There was no difference in the cellular morphology of the button stored in moxifloxacin-fortified Optisol-GS compared with Optisol-GS using EM. In the bioassay, the rate of nonviable cells in the moxifloxacin-fortified media compared with the control media was nonsignificant (P > 0.05). CONCLUSION: Moxifloxacin (250 microg/mL) seems to be safe as an additive agent for cornea storage media. It significantly reduces the rate of positive rim cultures and shows no signs of endothelial cytotoxicity as viewed by EM and by a bioassay of trypan blue and alizarin red.

Fungal keratitis at the new york eye and ear infirmary.

INTRODUCTION: This study was designed to review the clinical experience at our institution with fungal keratitis during a 16-year period. MATERIALS AND METHODS: A review of the clinical and microbiology records of the New York Eye and Infirmary identified 61cases of fungal keratitis in 57 patients between January 1, 1987 and June 1, 2003. The medical records of all patients were retrospectively reviewed to better delineate patient demographics, risk factors, etiologic organisms, treatment, and outcomes. RESULTS: A total of 5083 positive corneal cultures were recorded'from January 1, 1987 to June 1, 2003. Sixty-one eyes in 57 patients (37 women) were positive for fungus (1.2%). Three'patients had bilateral simultaneous infections. Candida albicans accounted for 29 of 61 cases (48%). Human immunodeficiency virus (HIV) seropositivity (15 eyes), chronic ocular surface disease (14 eyes), and trauma (7 eyes) were the most commonly associated risk factors. CONCLUSIONS: Our experience with fungal keratitis in the northeastern United States appears to be different than those reported from other areas of the United States. Serologic positivity for HIV and chronic ocular surface disease were the most common associated risk factors followed by trauma, herpes simplex keratitis, and contact lens use. Candida species predominated, whereas filamentous fungi were uncommon.

The incidence of fungal keratitis and endophthalmitis following penetrating keratoplasty.

PURPOSE: To determine the incidence of postkeratoplasty fungal endophthalmitis and keratitis at the New York Eye and Ear Infirmary. To determine whether there is a relationship between culture-positive corneoscleral donor material and postoperative infection. METHODS: The microbiologic records of corneoscleral donor rims submitted for culture following penetrating keratoplasty at the New York Eye and Ear Infirmary between January 1998 and January 2003 were reviewed. The incidence of rim cultures positive for fungi was tabulated. Clinical outcome measures were recorded for each patient receiving corneal donor tissue. RESULTS: Of 2466 donor corneoscleral rims cultured during the study period, 344 were positive for microbial growth (13%). Of those rims with positive cultures, 28 (8.6%) were positive for fungus. All fungi cultured were Candida species. Four of the 28 recipient eyes (14%) who received contaminated donor material went on to develop postkeratoplasty fungal infections. There were no cases of fungal infection in any postkeratoplasty patients in the absence of contaminated donor rims during the study period. Overall, there was a 0.16% incidence of fungal infection (4/2466) following penetrating keratoplasty. There were 18 positive donor rims identified in the first 4 years of the study, but there were 10 cases in the last 10 months of the study. CONCLUSIONS: The overall incidence of fungal infection following penetrating keratoplasty is low, but all cases in our study were associated with positive rim cultures. Whether prophylactic antifungal therapy would be of any benefit in the presence of a positive corneoscleral rim culture has not yet been determined.