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Biomedical subjects

U Gopinathan

Publications and source records attributed to U Gopinathan.

25 records · Page 2Linked to original sources

Haemophilus influenzae adherent to contact lenses associated with production of acute ocular inflammation.

Ten episodes of adverse responses to contact lens wear, including contact lens-induced acute red eye (CLARE), in which Haemophilus influenzae was isolated from contact lenses and/or from one of the external ocular sites at the time of the event, are described. All episodes occurred in patients wearing disposable hydrogel lenses on a 6-night extended-wear schedule. Two of the patients had recurrent episodes. H. influenzae was usually isolated in large numbers, and other bacteria or fungi colonizing the contact lens or the external ocular surface were usually present in low numbers. Those patients who were colonized with H. influenzae were more than 100 times as likely to have had a CLARE or infiltrative response than those subjects who were not colonized with this bacterium. H. influenzae colonization of the contact lens and eye may be subsequent to colonization of the nasopharynx because four of the seven patients presented with fever at the time of the event, with concurrent upper respiratory tract infection. Contact lens wearers should be made aware of the potential risk of CLARE associated with the wearing of contact lenses for extended periods during and subsequent to upper respiratory tract infection.

Acute Disease↗

Calcium alginate swab versus Bard Parker blade in the diagnosis of microbial keratitis.

A prospective comparative evaluation of Bard Parker blade no. 15 and calcium alginate swab in the collection of corneal material was conducted. The study group included 30 consecutive cases of bacterial (n = 17), fungal (n = 11), and mixed (n = 2) cases of microbial keratitis. The samples collected by blade and swab were processed in an identical manner for viable colony counts. The yields from blade and swab were compared using the proportion test, taking into consideration the mean counts of each organism. The swab yielded significantly greater growth than blade (p = 0.003) in mycotic ulcers. However, the two patients (2/11) who showed no growth by blade but were positive by swab had smears positive and were diagnosed as mycotic ulcers. The difference between the two methods was not significant for bacterial and mixed ulcers. Replacement of blade with calcium alginate swab did not appear to be advantageous for the investigation of infectious keratitis.

Alginates↗

Nocardial necrotizing scleritis after trauma. Successful outcome using cefazolin.

Nocardial necrotizing scleritis is uncommon, but potentially sight threatening. We report the occurrence of necrotizing scleritis in a 58-year-old farm worker after he sustained trauma with vegetable matter. Microbiological studies isolated Nocardia asteroides, sensitive only to cefazolin. Clinically the patient responded well to this drug, attaining a final visual acuity of 20/40, with complete resolution of the scleritis. Early isolation and testing for antibiotic sensitivity were responsible for the successful management of this patient.

Cefazolin↗

Sterility and the disinfection potential of Indian contact lens solutions.

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.

Animals↗

Donor corneoscleral rim contamination by gentamicin-resistant organisms.

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.

Bacteria↗

Ocular nocardia infections with special emphasis on the cornea.

Nocardia are aerobic, gram-positive, nonmotile and branching filamentous bacteria. Corneal infection by Nocardia is rare. Trauma is the most common predisposing factor. Isolated case reports of nocardial infection associated with contact lens wear and laser in situ keratomileusis (LASIK) have been reported. The clinical picture usually consists of superficial patchy infiltrates, which may be arranged in a wreath pattern. Presence of gram-positive, branching, beaded filaments that stain with 1% acid-fast stain (using 1% sulfuric acid, modified Kinyoun's method) in smears of corneal scrapings is suggestive of nocardial infection. Nocardia grow on commonly used media as tiny, white, dry colonies. Available knowledge and clinical experience suggest that although sulfacetamide eyedrops can be tried as the initial drug, trimethoprim-sulfamethoxazole and amikacin are effective drugs. Once therapy is initiated, the infiltrate responds promptly and resolves, forming a corneal scar with or without vascularization, and good visual recovery can be expected.

Anti-Bacterial Agents↗