Subject(s)
Adult , Aged , Aged, 80 and over , Cornea/microbiology , Corneal Diseases/microbiology , Corneal Transplantation/adverse effects , Enterocytozoon/genetics , Eye Infections, Fungal/microbiology , Female , Humans , Keratoconjunctivitis/microbiology , Male , Microsporidia/genetics , Microsporidiosis/microbiology , Middle Aged , Tissue DonorsABSTRACT
Potassium hydroxide (KOH) preparation is an underutilized modality in the diagnosis of mycotic keratitis. We have earlier shown its utility in the diagnosis of Nocardia and Acanthamoeba keratitis. The aim of this study was (i) to evaluate the sensitivity, specificity and predictive value of KOH preparation, and (ii) to compare its efficacy with other methods of corneal scraping examination, for the diagnosis of mycotic keratitis. The study was conducted in two phases. In phase I, randomized corneal scrapings were examined by KOH, Gram's stain, and lactophenol cotton blue (LPCB) in 91 infectious keratitis subjects. In phase II, 53 corneal scrapings were stained with KOH and calcofluor white (CFW), and viewed with bright field (KOH) and fluorescence (CFW) microscopy. The KOH and CFW readings were recorded by an observer masked to the clinical findings and culture results. Nineteen scrapings were examined by two masked observers. In 22 culture positive fungal keratitis patients in phase I, the sensitivity of KOH, Gram's stain, and LPCB methods was 100%, 86.4%, and 77.3%, respectively. In phase II, the specificities of KOH and CFW were identical (83.8%), while the sensitivities were 81.2% and 93.7%, respectively (p = 0.59), in 16 culture positive mycotic keratitis patients. There was no significant difference between the negative and positive predictive values of KOH and CFW. Furthermore, no significant interobserver variability was found in the specificity and sensitivity. The KOH method compares well with other microscopy methods in the diagnosis of keratomycosis and has a definite place in the armamentarium of diagnostic techniques.
Subject(s)
Benzenesulfonates/diagnosis , Cornea/microbiology , Double-Blind Method , Eye Infections, Fungal/diagnosis , Fungi/cytology , Gentian Violet/diagnosis , Humans , Hydroxides/diagnosis , Keratitis/diagnosis , Lactic Acid/diagnosis , Phenazines/diagnosis , Phenols/diagnosis , Potassium Compounds/diagnosis , Predictive Value of Tests , Prospective Studies , Sensitivity and SpecificityABSTRACT
Gentamicin is the most widely used antibiotic in the decontamination of donor cornea for penetrating keratoplasty. However, the incidence of resistance to gentamicin is on the rise. Bacterial isolates from 178 donor corneal rims were studied for gentamicin sensitivity. The overall rate of gentamicin resistance was 63.4%. At 86.2% the Pseudomonas. species had the highest rate of resistance, followed by Streptococci at 84.6%. The high rate of gentamicin resistance encountered by us and others suggest that either addition of a second antibiotic to corneal storage media or replacement of gentamicin by an antibiotic with a broader spectrum of activity may help reduce the risk of endophthalmitis following penetrating keratoplasty.
Subject(s)
Bacteria/drug effects , Cornea/microbiology , Drug Resistance, Microbial , Gentamicins/pharmacology , Humans , Microbial Sensitivity Tests , Organ Preservation , Sclera/microbiology , Tissue DonorsABSTRACT
Ocular infection associated with microbial contamination of contact lens care products is a major problem in contact lens wearers. The sterility and the antimicrobial activity of contact lens care systems reflect their suitability for disinfection of contact lenses. These factors remain to be evaluated for the various newer contact lens care products manufactured in India. In this study, 35 bottles of contact lens solutions marketed by different manufacturing units in India were tested for sterility. Seven solutions were tested for antimicrobial effectiveness employing the D value method of analysis. The D value is defined as the time required to reduce a population of organisms by 90% (one log unit). A standard inoculum of the ocular isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Aspergillus fumigatus, Fusarium solani, and Acanthamoeba castellanii were used as challenge organisms. Bacterial contamination was detected in 20 (57.1%) solution bottles and none yielded fungus or Acanthamoeba. Pseudomonas species were the most commonly encountered contaminant (11/20; 55%). Only sterile solutions were analyzed for antimicrobial activity. D values ranging between 12 and 20 minutes were demonstrated by six of the seven solutions against bacterial challenge. Good antifungal activity was noticed in five solutions against Fusarium solani though results varied with Aspergillus flavus and Candida albicans. All solutions were adequately effective against Acanthamoeba.