Safety and efficacy of eye drops from umbilical cord blood platelet lysate to treat resistant corneal ulcer

Background

Umbilical cord blood (UCB) is a novel treatment of resistant corneal ulcers owing to the unique anti-inflammatory molecules and growth factors it contains. Platelet lysates are a potential future alternative. The aim of the present study was to assess the role of human UCB platelet lysate in treating resistant corneal ulcers.

Methods

This was prospective, non-comparative, interventional case series involving 40 eyes of patients aged 6 - 65 years with persistent corneal ulcers from the Mansoura Ophthalmic Center and Mansoura Research Center for Cord Stem Cells. Patients were classified according to the cause of persistent corneal ulcer into four groups: group I, including 14 eyes with dry eye disease; group II, including six eyes post-keratoplasty; group III, including four eyes with corneal chemical burn; and group IV, including 16 eyes with persistent corneal ulcer from other causes. All participants underwent detailed ophthalmic examinations, and baseline and final best-corrected distance visual acuity (BCDVA) were recorded. Eye drops were prepared from UCB platelet lysate and administered to all patients along with detailed meticulous instructions for the method of use. Clinical progression of wound healing was continuously observed. The treatment response was identified as complete healing, improvement, or treatment failure.

Results

BCDVA improved significantly in all studied groups (all P < 0.05). In group I, complete healing, improvement, and treatment failure occurred in 71%, 29%, and 0% of cases. In group II, complete healing, improvement, and treatment failure occurred in 67%, 33%, and 0% of cases. In group III, complete healing, improvement, and treatment failure occurred in 50%, 50%, and 0% of cases. In group IV, complete healing, improvement, and treatment failure occurred in 63%, 12%, and 25% of cases. No adverse events associated with the treatment were observed or subjectively self-reports in the study period.

Conclusions

Eye drops from UCB platelet lysate were a novel therapeutic blood component with unique growth factors and anti-inflammatory compounds that could be an effective and safe treatment option in managing persistent corneal ulcers of different causes. A future randomized clinical trial with a large sample size and a longer follow-up is required to confirm these preliminary outcomes.

Comparison of corneal culture results obtained using the ESwab™ and Amies charcoal swab in canine and feline patients

OBJECTIVE

The objective of the study was to compare corneal culture results using the ESwab™ and Amies charcoal swab.

ANIMALS STUDIED

One hundred fourteen canine and fifteen feline eyes.

PROCEDURES

Retrospective analysis of Dick White Referrals bacterial and fungal corneal culture data was conducted. Results were included from canine and feline patients, which presented with suspected infectious keratitis that had samples taken using an Amies charcoal swab followed by an ESwab™ in the same eye. In respect to positive and negative cultures, a McNemar test was conducted comparing instances of disagreement between swab types, and the Kappa coefficient (κ) was calculated to assess the level of agreement between swab types.

RESULTS

The ESwab™ produced more positive corneal cultures (71/129 [55.0%]) than the Amies charcoal swab (41/129 [31.8%]). 2/129 eyes produced positive fungal cultures. Considering 37/129 eyes in which both swab types detected a positive corneal culture, the same bacterial species were cultured from each swab type in 34/37 (91.9%) eyes, and an additional bacterial species was cultured by the ESwab™ in 3/37 (8.1%) eyes. In 34/38 (89.5%), instances of disagreement between swab types, the ESwab™ showed a positive culture, and the Amies charcoal swab showed a negative culture from the same eye, and this difference was significant (p < 0.0001). There was a moderate level of agreement between results from both swab types (κ = 0.432).

CONCLUSIONS

ESwab™ sampling alone may be superior to Amies charcoal swabs for detecting presence of bacteria in suspected infectious keratitis in cats and dogs.

Unusual Corneal Sarcoidosis Manifestations

AIM

To document atypical presenting forms of ocular sarcoidosis at the corneal level.

METHODS

Case report.

RESULTS

A 63-year-old woman presented multiple uncommon unilateral primary corneal conditions as manifestation of ocular sarcoidosis, including peripheral ulcerative keratitis, sterile corneal infiltrate (corneal granuloma), and sterile infiltrates related to a corneal foreign body, requiring medical and surgical management to control the inflammatory symptoms and to preserve the integrity of the eyeball. An excisional biopsy of a nodule in the temporal conjunctiva was performed under topical anesthesia. Histological analysis revealed a non-caseating granuloma, confirming the diagnosis of ocular sarcoidosis.

CONCLUSION

When thinking of ocular involvement in patients with ocular sarcoidosis, it is essential to remember that manifestations such as peripheral ulcerative keratitis, sterile corneal infiltrate, and sterile foreign body-related infiltrates may be presentations of this disease.

Equine ulcerative keratitis in Belgium: Associated bacterial isolates and in vitro antimicrobial resistance in 200 eyes

PURPOSE

To describe bacterial isolates and associated antibiotic resistance from horses with ulcerative keratitis in Belgium.

METHODS

Medical records from horses with ulcerative keratitis presented to the ophthalmology service of the Veterinary teaching hospital of Liege, Belgium, between 2014 and 2021 were evaluated. Bacterial isolates were identified and VITEK^® 2 (Biomérieux) provided antimicrobial susceptibility testing and resistance detection.

RESULTS

Two hundred eyes of 196 horses were sampled. Ninety-seven eyes had a positive bacterial culture (48.5%) and 139 bacterial isolates were identified. Staphylococcus (63/139: 45.3%) and Streptococcus (33/139: 23.7%) were the most frequent genus isolated. Staphylococcus aureus (21/139: 15.1%) was the most frequent species isolated of which half were methicillin-resistant (MRS). Streptococcus equi subsp. zooepidemicus (19/139: 13.7%) was the second most identified bacterial isolate. Only two Pseudomonas species were isolated (2/139: 1.4%). The overall resistance of all bacterial isolates against chloramphenicol (12.4%) and fluoroquinolones (14.3%) was low. Resistance against tobramycin, polymyxin B, gentamicin, fusidic acid, tetracycline, and neomycin ranged from 40.8% to 58.6%. When separating the MRS from the other staphylococci, a significant difference was noted in percentage of resistance to gentamicin (p = .00026) and tetracycline (p = .00015). MRS were highly resistant to gentamicin (75%) and tetracycline (100%), whereas the remaining staphylococci were significantly less resistant to gentamicin (17%) and tetracycline (40.4%).

CONCLUSION

Although Pseudomonas species has been rarely cultured, our results are roughly consistent with previous studies. Multiple drug resistance was high and resistance to first-choice antibiotics in ulcerative keratitis was noted. These results warrant continued monitoring of susceptibility profile.

Breed prevalence of canine ulcerative keratitis according to depth of corneal involvement

OBJECTIVE

To investigate the breed prevalence of canine ulcerative keratitis (UK) according to the depth of corneal involvement.

PROCEDURES

Dogs diagnosed with ulcerative keratitis from 2008 to 2017 at the Triangle Animal Eye Clinic were included in this study. Only breeds with more than 20 eyes affected were selected. UK lesions were classified as superficial (Grade 1), stromal (Grade 2) or descemetoceles and perforations (Grade 3) and compared between brachycephalic (BC) and non-BC dog breeds.

RESULTS

Of 8877 dogs evaluated at Triangle Animal Eye Clinic from 2008 to 2017, 1109 eyes of 1018 dogs (male, 326 eyes; neutered male, 253 eyes; female, 211 eyes; spayed female, 316 eyes; and unknown sex, 3 eyes) aged between 0.1 and 19.2 years (mean ± standard deviation [SD], 8.33 ± 4.24 years) were diagnosed with UK. The number of eyes that was classified as Grade 1 was 359 eyes (187 non-BC and 172 BC), Grade 2 was 373 eyes (60 non-BC and 313 BC) and Grade 3 was 377 eyes (47 non-BC and 330 BC). Significant differences were observed between BC and non-BC dogs for all grades of UK. BC dogs were significantly more frequently affected by Grades 2 and 3 and less frequently by Grade 1 UK (P < .01). French bulldogs are more likely to be affected with Grade 1.

CONCLUSIONS

Brachycephalic dogs are more likely to have deeper corneal involvement in UK. This study provides novel data on the prevalence of superficial UK, which was low in BC dogs and high in non-BC breeds.

Using minimum inhibitory concentration values of common topical antibiotics to investigate emerging antibiotic resistance: A retrospective study of 134 dogs and 20 horses with ulcerative keratitis

OBJECTIVES

To identify the minimum inhibitory concentration (MIC) distribution for commonly used topical antibiotics from isolates of dogs and horses with ulcerative bacterial keratitis, and to investigate changes in MIC values over time and following treatment with topical fluoroquinolones.

ANIMALS STUDIED

One hundred thirty-four client-owned dogs and 20 client-owned horses with bacterial ulcerative keratitis.

PROCEDURE

Minimum inhibitory concentration values for 14 topical antibiotics were reported for canine and equine cases of bacterial ulcerative keratitis between 2013 and 2018. Changes in MIC values over time and after treatment with topical fluoroquinolones were reported.

RESULTS

The three most common bacterial genera isolated were Staphylococcus, Streptococcus, and Pseudomonas. Together, these represented 79.4% of canine cases and 77.4% of equine cases. Overall, isolates from horses tended to have lower MIC values, as did Pseudomonas isolates from both dogs and horses, compared to other bacterial genera, especially Staphylococcus spp. The MIC values of erythromycin and trimethoprim sulfa for Staphylococcus spp., and the MIC value of moxifloxacin for Pseudomonas significantly increased over time. Previous topical fluoroquinolone use was associated with a significant increase in the MIC value of ofloxacin in canine and equine Staphylococcus isolates and current topical fluoroquinolone use was associated with significant increases in the MIC values of ciprofloxacin, moxifloxacin, and ofloxacin in canine Staphylococcus isolates.

CONCLUSION

Patients previously or currently treated with topical fluoroquinolones, particularly in Staphylococcus infections, may require alternative antibiotics or additional antibiotic classes other than fluoroquinolones. Bacterial culture with MIC susceptibility testing should be highly recommended when a Staphylococcal infection is suspected.

Bilateral Boston keratoprosthesis type 1 in a case of severe Mooren's ulcer

INTRODUCTION

Mooren's ulcer is a painful, inflammatory chronic keratitis that affects corneal periphery, progressing centripetally, ultimately ending in perforation. The first line of treatment includes systemic immunomodulators, with surgery being the last option. We present a case of bilateral Boston keratoprosthesis implantation for severe Mooren's ulcer that responded differently in each eye.

CLINICAL CASE

A 32-year-old male with corneal opacification, anterior staphylomas, vision of hand movement, was started on systemic immunosuppression with cyclosporine. After two failed penetrating keratoplasties in each eye, high intraocular pressure despite diode cyclophotocoagulation, and cystic macular edema, we performed Boston keratoprosthesis type 1 in both eyes. The right eye responded initially well, with a best-corrected visual acuity of 20/80 and normal intraocular pressure. The left eye presented high intraocular pressure, which required cyclophotocoagulation, ultimately resulting in hypotony. Boston keratoprosthesis was performed but had peripheral corneal necrosis that progressed despite amniotic membrane transplantation and aggressive intensive treatment with medroxyprogesterone, autologous platelet-rich-in-growth-factors eye drops, and oral doxycycline. Thus, replacement of the semi-exposed Boston keratoprosthesis with tectonic penetrating keratoplasty was necessary. However, both eyes developed phthisis bulbi with final visual acuity of perception of light with poor localization.

CONCLUSION

Mainstay treatment of Mooren's ulcer is systemic immunomodulation. Surgical treatment must be considered only when risk of perforation, preferably with inflammation under control. Penetrating keratoplasty frequently fails, and Boston keratoprosthesis may be a viable option. However, postoperative complications, especially uncontrolled high intraocular pressure, corneal necrosis, and recurrence of Mooren's ulcer may jeopardize the outcomes and need to be addressed promptly with intensive topical and systemic treatment.

Bilateral Boston keratoprosthesis type 1 in a case of severe Mooren's ulcer

INTRODUCTION

Mooren's ulcer is a painful, inflammatory chronic keratitis that affects corneal periphery, progressing centripetally, ultimately ending in perforation. The first line of treatment includes systemic immunomodulators, with surgery being the last option. We present a case of bilateral Boston keratoprosthesis implantation for severe Mooren's ulcer that responded differently in each eye.

CLINICAL CASE

A 32-year-old male with corneal opacification, anterior staphylomas, vision of hand movement, was started on systemic immunosuppression with cyclosporine. After two failed penetrating keratoplasties in each eye, high intraocular pressure despite diode cyclophotocoagulation, and cystic macular edema, we performed Boston keratoprosthesis type 1 in both eyes. The right eye responded initially well, with a best-corrected visual acuity of 20/80 and normal intraocular pressure. The left eye presented high intraocular pressure, which required cyclophotocoagulation, ultimately resulting in hypotony. Boston keratoprosthesis was performed but had peripheral corneal necrosis that progressed despite amniotic membrane transplantation and aggressive intensive treatment with medroxyprogesterone, autologous platelet-rich-in-growth-factors eye drops, and oral doxycycline. Thus, replacement of the semi-exposed Boston keratoprosthesis with tectonic penetrating keratoplasty was necessary. However, both eyes developed phthisis bulbi with final visual acuity of perception of light with poor localization.

CONCLUSION

Mainstay treatment of Mooren's ulcer is systemic immunomodulation. Surgical treatment must be considered only when risk of perforation, preferably with inflammation under control. Penetrating keratoplasty frequently fails, and Boston keratoprosthesis may be a viable option. However, postoperative complications, especially uncontrolled high intraocular pressure, corneal necrosis, and recurrence of Mooren's ulcer may jeopardize the outcomes and need to be addressed promptly with intensive topical and systemic treatment.

Comparison of bacterial culture results collected via direct corneal ulcer vs conjunctival fornix sampling in canine eyes with presumed bacterial ulcerative keratitis

OBJECTIVE

To compare aerobic bacterial culture results between samples obtained from the corneal ulcer versus lower conjunctival fornix in eyes with presumed bacterial ulcerative keratitis.

ANIMALS STUDIED

Fifty five client-owned dogs diagnosed with ulcerative keratitis.

PROCEDURES

Ophthalmic examinations were performed on each dog including slit-lamp biomicroscopy and indirect ophthalmoscopy. Microbial swabs were collected by direct sampling of the infected corneal ulcer as well as the lower conjunctival fornix, of the same eye, using a sterile rayon-tipped swab. Samples were submitted to an outside reference laboratory for aerobic bacterial culture and sensitivity.

RESULTS

One hundred twelve samples were obtained from 56 eyes (55 dogs). Sixty-eight samples yielded bacterial growth. Positive growth from both sites was obtained in 31 eyes (55%). Six eyes yielded bacterial growth from the conjunctival fornix but not from the cornea. No bacterial growth was obtained from either sampling site in 19 eyes. Overall, 31/56 (55%) corneal samples were positive and 37/56 (66%) conjunctival fornix samples were positive. Comparison of organisms isolated from the two collection sites of the same eye revealed an exact correlation in 42/56 (75%) eyes and differed in 14/56 (25%) eyes. Twenty different bacterial isolates were obtained from 68 positive samples. Gram-positive (71%) organisms were more common than Gram-negative (29%). The most commonly isolated organisms were Staphylococcus pseudintermedius (25%), beta-hemolytic Streptococcus spp. (23%), and Pseudomonas aeruginosa (12%). Methicillin-resistant organisms were isolated in 9% of samples.

CONCLUSION

Sampling from the conjunctival fornix may be a suitable alternative to direct ulcer sampling in eyes with compromised corneal structural integrity.

Equine ulcerative keratitis with furrow: A review of the outcomes of 72 cases from 1987 to 2015

BACKGROUND

Ulcerative keratitis with peripheral furrow formation is a poorly-described condition which has been associated with a grave prognosis due to rapid necrosis of the cornea.

OBJECTIVE

To describe the infectious aetiologies associated with furrow-forming ulcerative keratitis, its overall clinical course and the efficacy of medical and surgical intervention in horses.

STUDY DESIGN

Retrospective clinical case series.

METHODS

Medical records of 72 horses which presented with furrow-forming ulcerative keratitis at the University of Florida between 1987 and 2015 were reviewed.

RESULTS

Seventy-two horses (72 eyes) with furrow-forming ulcerative keratitis were treated at the University of Florida between 1987 and 2015. Of these, a definitive aetiologic diagnosis was available for 37 eyes. Ten of 37 eyes (27%) were diagnosed with fungal keratitis based on cytology of corneal scraping, culture, histopathology and/or fungal PCR. Fourteen of 37 eyes (38%) were diagnosed with a mixed fungal and bacterial keratitis. Thirteen of 37 eyes (35%) were diagnosed with bacterial keratitis. Overall, 26 of 72 total eyes were treated with medical therapy alone (36%). Forty-six of 72 eyes were treated medically and surgically (64%). Of the 26 eyes which received medical therapy, 20 healed with a positive visual outcome (77%) and 6 eyes were non-visual (23%). Of the 46 eyes which received surgical intervention, 40 healed with a positive visual outcome (87%), while six eyes were non-visual (13%). Altogether, 60 of 72 eyes healed with a positive visual outcome following medical or surgical treatment of furrow-forming ulcerative keratitis (83%). Twelve of 72 eyes failed treatment (17%), with six eyes requiring enucleation and six globes becoming phthisical after treatment.

MAIN LIMITATIONS

Inconsistencies in available medical record data due to the large span of time (1987-2015) are inherent in this retrospective study, along with gradual evolution of corneal surgical techniques and medical therapies over the decades.

CONCLUSIONS

Furrow-forming ulcerative keratitis was associated with a positive visual outcome in 83% of horses treated at the University of Florida between the years 1987 and 2015. Furrow formation may be associated with either fungal or bacterial infection.

In vitro assessment of the long-term stability of the inhibitory effects of canine and feline plasma on MMP 2 and 9

PURPOSE

To evaluate the effect of increasing storage time on the inhibitory effects of canine and feline plasma on matrix metalloproteinases (MMP) 2 and 9 in vitro.

METHODS

Matrix metalloproteinases 2 and 9 activity in the presence of canine plasma stored for 57, 155, 222, 316, 367, and 438 days, and feline plasma stored for 17, 198, 565, and 954 days was assayed using a commercially available colorimetric assay kit.

RESULTS

For canine plasma, the MMP 2 activity for older samples was not significantly different than the 57-day sample (P = 0.2025-0.9033). Two canine samples had significantly lower MMP 9 activity than the 57-day sample (367 days: P = 0.0099, 438 days: P = 0.0348, others P = 0.0778-0.9928). For feline plasma, storage time did not significantly affect inhibition of MMP 2 and MMP 9 activity (ANOVA, P = 0.2688 and P = 0.2404, respectively).

CONCLUSIONS

Increasing storage time does not significantly decrease the inhibiting activity of plasma on MMP 2 and 9 for up to 14 months in dogs and 31 months in cats.

Surgical management of peripheral corneal thinning disorders

The peripheral corneal thinning disorders are associated with degenerative, autoimmune, or infective causes. Corneal thinning can subsequently affect the visual acuity either by inducing severe astigmatism or by progressive involvement of the central cornea. In addition to this, the integrity of the eye is at risk. Medical management is necessary to address the underlying inflammatory or infectious causes; however, most of the cases require surgical intervention for tectonic support or for visual rehabilitation in patients with severe astigmatism. Preoperative investigations help in mapping the corneal curvature and thickness, thereby facilitating planning of treatment. Routine corneal transplantation techniques do not yield good results in peripheral corneal thinning disorders. Various surgical modifications have been described to manage these challenging cases. We review the available literature on causes and management of peripheral corneal thinning disorders.

Comparison of 3 corneal cytology collection methods for evaluating equine ulcerative keratitis: Cytobrush, kimura platinum spatula, and handle edge of scalpel blade

PURPOSE

To compare corneal cytology samples from three common sampling techniques: cytobrush (CB), Kimura platinum spatula (KS), and the handle edge of a scalpel blade (SB).

METHODS

Equine patients presenting to the University of Florida College of Veterinary Medicine with ulcerative keratitis were included. Following diagnosis of corneal ulcer and sampling for microbial culture, two cytology samples per technique were collected with sterile CB, KS, and SB in a randomized order. Cytologic evaluation was performed by two observers masked to collection method. Objective measures of sample cellularity, quality, distribution, and identification of infectious organisms were recorded per 10 monolayer cell populations using 50× magnification with oil immersion which were compared to culture results. Variables were compared using ANOVA with Student's t test when appropriate and Cohen's kappa (k) to evaluate inter- and intra-observer agreement (IOA) between observers and techniques.

RESULTS

Twenty equine patients (120 samples) were included. The IOA between observers was substantial (k = 0.75 ± 0.06) for cytological parameters. SB provided the most cellular samples (P < .01). There was a trend toward agreement (k = 0.12 ± 0.16) in technique for sample quality (P = .08). CB and SB had significantly poorer cell distribution than KS (P < .05). Infection was confirmed in 12 of 20 patients with SB and CB techniques having a significantly higher diagnostic yield than KS (P < .05) and was most consistent with infection confirmed on culture.

CONCLUSIONS

The SB provided the most diagnostic samples but all three techniques are clinically useful in evaluating equine ulcerative keratitis.

Complicated corneal ulcer. Case report

Corneal ulcers are considered an ophthalmologic emergency because of their potential to permanently impair vision or perforate the eye. The therapeutic management includes medical therapy and in case of failure, surgical care such as amniotic membrane transplantation. We present the case of a 76-year-old male, admitted for sudden visual loss in the left eye, associated with ocular pain, tearing, and photophobia. The patient was diagnosed with superficial ulcerative keratitis with hypopyon and acute exogenous anterior uveitis for which he underwent medical treatment, both general and topic, with a good evolution during a month. After a month, the patient presented with the corneal ulcer perforated. Surgery was performed in the left eye by covering the ocular surface with an amniotic membrane using the Motowa's sandwich technique. After one year, the same patient was successfully operated for cataract removal and posterior chamber intraocular lens implantation in the left eye.

Acinetobacter junii as an aetiological agent of corneal ulcer

Rods of the Acinetobacter genus are present mainly in the external environment (e.g. water, soil) and in animals, while in humans they may comprise physiological flora. The main pathogenic species is Acinetobacter baumannii complex, which constitutes a common cause of nosocomial infections, particularly in patients with underlying diseases and risk factors (e.g. prior broad-spectrum antibiotic therapy, malignancy, central venous catheter, mechanical ventilation); however, infections of the eye caused by strains of Acinetobacter spp. are very rare. We report a unique case of community-acquired corneal ulcer caused by Acinetobacter non-baumannii (possibly A. junii), in a patient with no risk factors identified. The case highlights the need for obtaining a sample from the cornea for bacteriological culture in the case of suspected ophthalmic infection as identification of the pathogen, and assessment of its susceptibility profile enables proper antibiotic therapy, improves the outcome and may constitute an eyesight-saving management.

Equine keratomycosis in Switzerland: a retrospective evaluation of 35 horses (January 2000-August 2011)

REASON FOR PERFORMING STUDY

Keratomycosis is a severe disease in horses. Geographical differences in fungi causing keratomycosis and susceptibility of the organisms to antifungal drugs exist but few previous publications on this disease originate from Europe.

OBJECTIVE

To retrospectively compare the clinical data of 36 eyes with keratomycosis, diagnosed in 35 horses between January 2000 and August 2011 at the Vetsuisse Faculty of Switzerland. Case history, season, prior treatment, clinical appearance, surgical and medical treatment, treatment duration, and globe survival were evaluated.

STUDY DESIGN

Retrospective case series.

METHODS

Medical records of horses with a definitive cytological or histological diagnosis of keratomycosis were reviewed.

RESULTS

Thirty-one of 36 eyes (86.1%) presented with ulcerative keratitis, 2/36 (5.55%) had diffuse corneal infiltration, 2/36 (5.55%) had superficial punctate keratitis and 1/36 (2.8%) had a fluorescein-negative fungal plaque. Two of 6 fungal cultures produced Aspergillus spp. Thirty eyes received medical and surgical treatment, while 3 eyes were treated medically only. In 3 horses the globe was removed at the time of first presentation. Sex, age, prior treatment with antimicrobials or steroids, or type of surgical approach did not significantly influence the outcome. Twenty-three of 36 eyes (63.9%) were at least partially visual, 11/36 eyes (30.5%) were enucleated and 2 horses (2/36 eyes, 5.6%) were subjected to euthanasia. Treatment protocols were compared in the 31 eyes with ulcerative keratitis. In this group, 3/31 globes were immediately enucleated, 16/31 eyes were treated topically with voriconazole or voriconazole/fluconazole and 12/31 with other antifungal drug combinations. The different medication protocols did not significantly affect the outcome.

CONCLUSIONS

There were no significant differences in outcome between different medical treatment protocols or types of surgical approach.

POTENTIAL RELEVANCE

Future studies in central Europe should focus on the identification of fungal pathogens, susceptibility patterns and the efficacy of antifungal drug therapies.