Laboratory Diagnosis in Fungal Keratitis

Wilson, Louis A.; Sexton, Robert R.

doi:10.1016/0002-9394(68)91284-1

Cited by 32 publications

(11 citation statements)

References 20 publications

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“…If the stained smear of scrape from an ulcer is thick, the hyphae will be interspersed throughout the necrotic tissue and their identification may be difficult or impossible. 22 Similarly, in KOH smears, Nocardia was easily recognised as very fine, intertwined, narrow, delicate, branching filaments, whereas in Gram-stained smears, Nocardia appeared as Gram-positive, beaded, coccoid and thin branching filaments, and were difficult to identify. In Kinyoun's acid-fast stained smears, Nocardia appeared as thin, pink, branching filaments on a blue background.…”

Section: Discussionmentioning

confidence: 99%

Microbiological diagnosis of infective keratitis: comparative evaluation of direct microscopy and culture results

Bharathi

Ramakrishnan²,

Ravindran³

et al. 2006

British Journal of Ophthalmology

127

102

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Aims: To determine the sensitivity, specificity and predictive values of potassium hydroxide (KOH) wet mount, Gram stain, Giemsa stain and Kinyoun's acid-fast stain in the diagnosis of infective keratitis. Methods: A retrospective analysis of all patients with clinically diagnosed infective keratitis presenting between September 1999 and September 2002 was carried out. Corneal scrapes were taken and subjected to direct microscopy and culture. Results: 3298 eyes of 3295 consecutive patients with infective keratitis were evaluated, of which 1138 (34.51%) eyes had fungal growth alone, 1069 (32.41%) had bacterial growth alone, 33 (1%) had Acanthamoeba growth alone, 83 (2.5%) had mixed microbial growth and the remaining 975 (29.56%) had no growth. The sensitivity of KOH wet mount was higher (99.3%; 95% confidence interval (CI) 98.6 to 99.6) in the detection of fungi, 100% (95% CI 90.4 to 100) in the detection of Nocardia and 91.4% (95% CI 75.8 to 97) in the detection of Acanthamoeba) than that of Gram-stained smears (89.2% (95% CI 87.3 to 90.8) in fungi, 87% (95% CI 73.0 to 94.6) in Nocardia and 60% (95% CI 42.2 to 75.6) in the detection of Acanthamoeba) in the detection of fungi, Nocardia and Acanthamoeba. 1764 of 3295 (53.54%) patients presented more than 7 days after onset of illness and 84.69% of the eyes had corneal ulcers with size .2 mm in diameter. Positivities of KOH (44.46%; p,0.001) and Gram-stained smears (77.37%; p,0.001) were found to be higher among eyes with larger ulcers (.2 mm) than among eyes with smaller ulcers (,2 mm). Conclusion: KOH smear is of greater diagnostic value in the management of infective keratitis, and it is recommended in all clinics without exception for establishing timely treatment.

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Section: Discussionmentioning

confidence: 99%

Microbiological diagnosis of infective keratitis: comparative evaluation of direct microscopy and culture results

Bharathi

Ramakrishnan²,

Ravindran³

et al. 2006

British Journal of Ophthalmology

127

102

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“…Hyphae were hyaline and septate, key features being the production of hyaline blastoconidia forming chains of darkly pigmented thick-walled arthroconidia. Though listed as one of the etiological agents of oculomycosis, their isolation is considered signifi cant only if fungal elements are observed in direct microscopy [27][28][29] . In the present study, strict aseptic precaution taken during the collection and inoculation of samples at the site of collection and visualization of fungal elements in direct microscopy helped us labeling the isolates of A. pullulans as an etiological agent.…”

Section: Discussionmentioning

confidence: 99%

Laboratory Diagnosis in Ulcerative Keratitis

Khanal

Deb²,

Panda³

et al. 2005

Ophthalmic Res

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Aims: To identify the common bacterial and fungal isolates from corneal ulcers and to determine the antimicrobial susceptibility patterns of bacterial isolates to commonly used antibiotics at B.P. Koirala Institute of Health Sciences (BPKIHS), eastern Nepal. Culture and direct microscopic correlation and reliability were also compared. Methods: All patients with suspected corneal ulceration presenting to the Ophthalmology Department of BPKIHS from 1st August 1998 to 31st July 2001 were evaluated. Corneal scraping was performed and processed for direct microscopy and culture for bacterial and fungal isolates. Bacterial isolates were subjected to antimicrobial susceptibility testing. Results: Of 447 specimens examined direct microscopy was positive in 216 (48%) specimens. Culture positivity could be correlated with direct microscopy in 179 (83%) of specimens. Growth of etiologic agents was found in 303 (67.8%) samples. Of these 145 (47.8%) had pure fungal growth, 103 (34%) had pure bacterial growth and 55 (18.2%) had mixed fungal and bacterial infection. The commonest fungal pathogen was Aspergillus spp.in 78 (38.4%) followed by Fusarium spp. in 45 (22%). Aureobasidium sp. was isolated in 25 (12.3%) samples. Staphylococcus aureus (93, 56.7%) dominated the scene as the commonest bacterial agent. Streptococcus pneumoniae (33, 20%) was second in the list. Most of the bacterial isolates were sensitive to commonly used antibiotics. Conclusion: This study emphasizes the importance and need of the continued surveillance of the agents and their antimicrobial susceptibility for the prevention and management of corneal ulcers and their complications.

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“…A keratectomy or corneal biopsy may be necessary to obtain adequate material if the infection is deep in the stroma. It is important to remember that negative culture results do not rule out a fungal infection (Wilson and Sexton 1968 ;Lieberman 1973).…”

Section: Discussionmentioning

confidence: 99%