c.i.-fluorescent-brightening-agent-28 and Eye-Infections--Fungal

The incidence of fungal keratitis demonstrates significant geographic and climatic variation. We report on the characteristics of the potassium hydroxide/calcofluor white (KOH-CFW) preparation observed at a tertiary center in Northern California, a region with a low incidence of fungal keratitis.. Culture-proven cases of microbial keratitis during a 5-year period were retrospectively reviewed. The sensitivity, specificity, and posttest probabilities were determined for the KOH-CFW assay. These results were compared with documented clinical impression and values reported in the literature.. Three hundred three of 368 episodes of microbial keratitis during the study period documented the results of a fungal culture, KOH-CFW assay, and a clinical impression. Twenty-one (6.9%) of these cultures were positive for fungal organisms. The sensitivity and specificity of the KOH-CFW test were 29% and 93%, respectively. Clinicians' initial clinical impression based solely on patients' history and examination, without the aid of any histopathologic or biochemical test results, demonstrated a sensitivity and specificity of 33% and 89%, respectively.. The observed sensitivity and specificity of the KOH-CFW preparation are significantly lower than many previously reported values. In regions with low incidence of fungal keratitis, the KOH-CFW preparation may have diagnostic performance similar to that of the clinical impression formed only on the basis of history and physical examination.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Benzenesulfonates; California; Child; Child, Preschool; Cornea; Eye Infections, Fungal; Female; Fluorescent Dyes; Follow-Up Studies; Fungi; Humans; Hydroxides; Incidence; Indicators and Reagents; Infant; Infant, Newborn; Keratitis; Male; Microscopy, Fluorescence; Middle Aged; Potassium Compounds; Reproducibility of Results; Retrospective Studies; Young Adult

To assess the sensitivity of potassium hydroxide and calcofluor white (KOH+CFW) mount in the diagnosis of Pythium keratitis and concordance among microbiologists.. Three microbiologists evaluated the microscopic images of KOH + CFW mounts of confirmed cases of Pythium and fungal keratitis seen between January 2019 and February 2021. The filaments were compared using specific differentiating features. The sensitivity and specificity of KOH + CFW in diagnosing Pythium infection were evaluated along with concordance among the microbiologists.. Sixty consecutive cases with confirmed growth of fungus or Pythium insidiosum (n = 29) were evaluated. The sensitivity of KOH + CFW in the correct identification of Pythium filaments ranged from 79.3% to 96.5% among three microbiologists. There was good interobserver (k = 0.76-0.90) and intraobserver (k = 0.70-0.97) agreements among three microbiologists. The differentiating findings (P < 0.0001) suggestive of Pythium filaments were the absence of septae in 23 (79.3%) and collapsed walls in 22 (75.9%) cases.. KOH + CFW has good sensitivity and specificity in the diagnosis of Pythium keratitis with good interobserver and intraobserver concordance.

Topics: Benzenesulfonates; Coloring Agents; Cornea; Eye Infections, Fungal; Fungi; Humans; Hydroxides; Keratitis; Potassium Compounds; Pythium

Fungal keratitis is a common disease that causes blindness. An effective animal model for fungal keratitis is essential for advancing research on this disease. Our objective is to develop a novel mouse model of Fusarium solani keratitis through the inoculation of fluorescent-labeled fungi into the cornea to facilitate the accurate and early identification and screening of fungal infections. F. solani was used as the model fungus in this study. In in vitro experiment, the effects of Calcofluor White (CFW) staining concentration and duration on the fluorescence intensity of F. solani were determined through the mean fluorescence intensity (MFI); the effects of CFW staining on the growth of F. solani were determined by the colony diameter. In in vivo experiment, the F. solani keratitis mice were induced and divided into a CFW-unlabeled and CFW-labeled groups. The positive rate, corneal lesion score and several positive rate determination methods were measured. The MFIs of F. solani in the 30 μg/ml CFW-30 min, 90 μg/ml CFW-10 min and 90 μg/ml CFW-30 min groups were higher than that in the 10 μg/ml CFW-10 min group (P < 0.01). Compared with the 30 μg/ml CFW-30 min group, only the 90 μg/ml CFW-30 min group showed higher MFI (P < 0.05). No significant difference was observed in the colony diameter in the CFW unstained group compared with that in the 10, 30, 90, 270, or 810 μg/ml CFW groups stained for either 10 or 30 min (P > 0.05). No significant differences (P > 0.05) were observed for the positive rate or the corneal lesion scores between the CFW-unlabeled and the CFW-labeled group. On day 1 and 2, the positive rates of the infected corneas in the scraping group were lower than those in the fluorescence microscopy group (P < 0.05). On day 3, these observe methods showed no significant difference (P > 0.05). Thus, these experiments established a novel murine model of F. solani keratitis utilizing fluorescent labeled fungi. This model facilitates the accurate identification and screening of fungal infections during the early stages of fungal keratitis and provides a novel and reliable technology to study the fungal keratitis.

Topics: Animals; Benzenesulfonates; Corneal Ulcer; Disease Models, Animal; Eye Infections, Fungal; Fluorescent Dyes; Fusariosis; Fusarium; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Staining and Labeling

The aim of this study was to develop a quick and economical method for the diagnosis of fungal keratitis. Corneal scrapings were obtained from consecutive patients (n = 165) with clinically suspected fungal keratitis and were used for culture and to prepare two smears. Potassium hydroxide stain followed by calcofluor white stain was added to one smear and Giemsa stain followed by calcofluor white stain was added to the second. In comparison with the fungal culture results, the sensitivity of potassium hydroxide wet mounts was 81.0% and following the addition of calcofluor white was 96.6% in diagnosing fungal keratitis, whereas sensitivity using Giemsa stain was 39.7% and following the addition of calcofluor white was 98.3%. The Giemsa stain detected 23 cases of bacterial infection, of which six cases were mixed fungal and bacterial infections. Giemsa stain followed by calcofluor white was considered to be the better method for diagnosing fungal keratitis due to its high sensitivity combined with its ability to identify bacterial or mixed infections.

Topics: Azure Stains; Benzenesulfonates; Cornea; Eye Infections, Fungal; Humans; Hydroxides; Keratitis; Microscopy; Potassium Compounds; Staining and Labeling

To compare the efficacy of a battery of routine and special histologic stains for the detection of acanthamoeba keratitis.. Observational study.. Nine patients with culture-proven infectious keratitis whose clinical differential diagnosis included acanthamoeba and who had undergone penetrating keratoplasty were identified. Three cases each of culture-proven acanthamoeba, fungal, and herpes simplex keratitis were reviewed. Serial sections of the keratoplasty specimens were stained with hematoxylin and eosin, periodic acid-Schiff (PAS), Gomori methanamine silver (GMS), giemsa, Gram, calcofluor white, and acridine orange. Sections were reviewed in a random order and a masked fashion and classified as positive or negative for acanthamoeba, fungus, or herpes.. The correct diagnosis was made by examination of the hematoxylin and eosin stained slides in all cases. Correct diagnoses in decreasing order of frequency were made for slides stained with PAS, GMS, acridine orange, calcofluor white, giemsa, and Gram. There were false-positive diagnoses made only with calcofluor white and acridine orange stained slides because of staining of extracellular debris and other material.. When sections are examined by an experienced observer, hematoxylin and eosin is useful compared with calcofluor white, acridine orange, GMS, PAS, giemsa, and Gram stains for the detection of acanthamoeba keratitis.

Topics: Acanthamoeba Keratitis; Acridine Orange; Benzenesulfonates; Cornea; Double-Blind Method; Eosine Yellowish-(YS); Eye Infections, Fungal; False Positive Reactions; Fluorescent Dyes; Hematoxylin; Humans; Keratitis, Herpetic; Keratoplasty, Penetrating; Microscopy, Fluorescence; Predictive Value of Tests; Reproducibility of Results; Staining and Labeling