Cultura de material provindo de úlceras de córnea em laboratório de referência

Antifungal susceptibility testing of yeast isolated from corneal infections INTRODUTIONFungi are opportunistic agents which rarely infect healthy corneas of immunocompetent individuals. Systemic and local underlying diseases may render the corneal tissues susceptible to infections with these organisms (1) . Trauma, specially related to organic materials, topical use of steroids and antibiotics (2)(3) , contact lens wear, surgical procedures, contamination of eye solutions, inappropriate maintenance of contact lenses (4) , systemic infections as well as any disease associated with immunodeficiency are considered risk factors for fungal eye infections (5) . In Brazil, the incidence of fungal eye infections ranges from 3.8 to 10%, depending on the site of the infection, the diagnostic tools available for fungal infections in the medical center and the seasons related to the studied period (6)(7)(8)(9) . The occurrence of keratomycosis is of great importance, not only because of diagnostic problems but also due to the severity of clinical manifestations and poor outcome despite antifungal treatment. The severity and progression of the fungal infection usually depend on the existence of Purpose: To report the antifungal susceptibility profile of yeast isolates obtained from cases of keratitis. Methods: Susceptibility testing of 15 yeast strains isolated from corneal infections to amphotericin B, fluconazole, itraconazole and ketoconazole was performed using the NCCLS broth microdilution assay. Results: Most episodes of eye infections were caused by Candida albicans. The antifungal drugs tested showed the following minimal inhibitory concentration values against yeast isolates: 0.125-0.5 µg/ml for amphotericin B; 0.125->64.0 µg/ml for fluconazole; 0.015-1.0 µg/ml for itraconazole and 0.015-0.125 µg/ml for ketoconazole. Despite the fact that all Candida isolates were judged to be susceptible to azoles, one isolate showed a minimal inhibitory concentration value significantly higher than a 90% minimal inhibitory concentration of all tested isolates. Rhodotorula rubra was resistant to fluconazole and itraconazole. Conclusions: Despite the fact that most yeast isolates from corneal infections are usually susceptible to amphotericin B and azoles, they exhibit a wide range of minimal inhibitory concentration values for antifungal drugs. The identification of strains at species level and their susceptibility pattern to antifungal drugs should be considered before determining the concentration to be used in topical antifungal formulations in order to optimize therapeutic response in eye infections.ABSTRACT

Section: Antifungal Susceptibility Testing Of Yeast Isolated From Cormentioning

confidence: 99%

Antifungal susceptibility testing of yeast isolated from corneal infections

Mascaro¹,

Hofling-Lima²,

Gompertz³

et al. 2003

“…This alteration can be analyzed for S. aureus groups and, possibly, for Pseudomonas sp, the susceptibilities in Study "A" being 84.2% and 86.8%, respectively, and in Study "B" 16,17 92.2% and 100%, respectively. The number of positive isolates of other microorganisms found in Study "B" was not significant, not allowing analysis and comparison in the present study.…”

Section: Discussionmentioning

confidence: 99%

“…There are several explanations for this fact like the presence of viral infections, use of topical antibiotics before cultures were performed, insufficient material, the presence of microorganisms that do not grow in regular media such as anaerobic bacteria and Mycobacteria 11,16 . Gram positive cocci are the most frequent bacteria isolated from conjuntival, corneal and intraocular infection in several series and also the most frequent isolated from conjunctival normal flora 1,2,11,10,17 . The microorganisms isolated from the eyes are more susceptible to tobramycin than to gentamicin but the difference between the susceptibilities of these two antibiotics is smaller in the recent study (Tables 1, 2).…”

Section: Discussionmentioning

confidence: 99%

Alterations in ocular pathogen susceptibility to gentamicin and tobramycin

Moeller¹,

Branco²,

Yu³

et al. 1999

Alterations in ocular pathogen susceptibility to gentamicin and tobramycinPurpose: To evaluate and compare the "in vitro" susceptibility of ocular bacterial isolates to aminoglycoside antibiotics (gentamicin and tobramycin) and to analyze the alteration in susceptibility after 14 years of introduction of tobramycin in Brazilian ophthalmic practice.Methods: The results of antibiotic susceptibility tests in a period of three years with 887 bacterial strains (Study "A") were retrospectively analyzed and then compared with the results obtained fourteen years ago with 124 microorganisms (Study "B"), when tobramycin was first tested in Brazil for isolated eye strains. In both studies, the data analyzed were from the files of the Ocular Microbiology Laboratory of the Federal University of São Paulo.Results: The "in vitro" effectiveness of both antibiotics regarding the total number of positive isolates was significantly higher for tobramycin in both studies. An increase in the Staphylococcus aureus strains resistant to tobramycin and only a decreasing trend in the number of microorganisms resistant to gentamicin was observed. With Pseudomonas sp, a strong tendency to the increase of susceptibility to gentamicin and to the appearance of strains resistant to tobramycin occurred.Conclusions: The introduction of tobramycin in the treatment of ocular infections and the possible decrease in number of gentamicin prescriptions during the last fourteen years might be the cause of modifications in the susceptibility observed in the total of positive isolates mainly Staphylococcus aureus and Pseudomonas sp. For the isolated microorganisms from the conjunctiva, the sensitivity to both antibiotics was equivalent. Alterações na sensibilidade dos patógenos oculares à gentamicina e à tobramicinaOs autores declaram não possuírem interesses financeiros no desenvolvimento deste estudo.(1)

“…A amicacina foi o antibiótico mais eficaz em relação à Pseudomonas aeruginosa, porém com atividade biocida de apenas 60%. Em uma pesquisa foi observado que a amicacina diminuiu sua eficácia frente às bactérias Gram negativas, quando a suscetibilidade das Pseudomonas spp caiu de 100% para 55,5% (38) . Registro recente demonstrou queda na atividade biocida in vitro da gentamicina e tobramicina a todos patógenos testados, no período de 15 anos (39) .…”

Section: Tabela 1 Distribuição Das Freqüências Das Bactérias Isoladaunclassified

Microbiota bacteriana da conjuntiva de doadores de córnea

Araújo¹,

Scarpi²

2004

Objetivos: Quantificar e qualificar a microbiota aeróbia da conjuntiva de doadores de córnea segundo a interferência do intervalo de tempo entre o óbito e a colheita do espécime conjuntival, a causa do óbito e a idade do doador e avaliar a atividade biocida de determinados antibióticos aos microrganismos isolados. INTRODUÇÃOA colonização bacteriana da pele, membranas e mucosas, como a conjuntiva, inicia-se logo após o nascimento e não se relaciona apenas à contaminação no canal de parto, mas também aos microrganismos presentes no meio ambiente (1) . A freqüência registrada de cultura positiva da conjuntiva de olhos de doadores de córnea, sem tratamento ocular prévio, varia de 43 a 100% (2)(3) . O aumento do número de microrganismos é favorecido pelas alterações pós-morte, como o cessar do piscar e do fluxo lacrimal (4)(5) . A predominância das mesmas espécies de bactérias in vivo e pós-óbito indica que a poluição do ambiente é pouco importante como origem da contaminação (4) . As bactérias isoladas mais freqüentes foram Staphylococcus epidermidis, Staphylococcus aureus e difteróides (3) .