Superficial corneal foreign body: laboratory and epidemiologic aspects

OBJETIVOS: Identificar por meio de cultura e bacterioscopia os microrganismos veiculados por corpo estranho corneal e sua sensibilidade aos antibióticos em teste de antibiograma. MÉTODOS: Foi realizado estudo prospectivo em 101 pacientes que procuraram o Pronto-Socorro de Oftalmologia do Hospital São Paulo-UNIFESP/EPM, com diagnóstico de corpo estranho corneal. Previamente a qualquer tratamento o corpo estranho e amostra do fundo de saco conjuntival ipsilateral foram coletados em tubos separados com tioglicolato. Realizou-se semeadura em meios sólidos de ágar sangue, chocolate, Sabouraud e exame bacterioscópico com as colorações de Gram e Giemsa e antibiograma. Culturas positivas para o corpo estranho foram comparadas com as de fundo de saco conjuntival para excluir contaminação com flora normal. RESULTADOS: Cerca de 92% dos pacientes foram do sexo masculino, com idade média de 35 anos. O olho direito foi acometido em 62,4% (intervalo de confiança 95%: 52,2 - 71,8%) da amostra e 32,7% (intervalo de confiança 95%: 23,7 - 42,7%) apresentou crescimento bacteriano positivo em cultura. Os microrganismos encontrados nas culturas dos corpos estranhos foram: Streptococcus, alpha-hemolytic (n=4), Staphylococcus aureus (n=4), Staphylococcus, coagulase-negative (n=4), Corynebacterium xerosis (n=3), bacilo gram-positivo não identificado (n=2), Moraxella sp (n=1), Serratia sp (n=1), Acynetobacter sp (n=1). O antibiograma revelou que 95% dos casos foram sensíveis ao cloranfenicol e 90% a ciprofloxacina, antibióticos usados na rotina de nosso serviço. CONCLUSÃO: O corpo estranho corneal foi importante vetor de contaminação, porém a grande maioria dos microrganismos isolados foi sensível a antibioticoprofilaxia empregada no tratamento.

Superficial corneal foreign body: laboratory and epidemiologic aspects.

PURPOSE: To determine by bacterioscopy and culture the microorganisms carried by corneal foreign body and their sensitivity to antibiotics by antibiotic sensitivity test. METHODS: A prospective study was carried out and information was collected on 101 patients who presented with corneal foreign body at the São Paulo Hospital Eye Emergency Service. Prior to any treatment, a sample of the ipsilateral inferior conjunctival fornix and the foreign body were collected and immersed in thioglycolate broth. Samples were sown on solid culture media including blood, chocolate and Sabouraud agar. Bacterioscopic examination using Gram and Giemsa staining and sensitivity test were performed. Positive foreign body culture results were compared to ipsilateral conjunctival fornix culture to exclude possible normal flora growth. RESULTS: Approximately 92% of patients were males with a mean age of 35 years and in 62.4% (95% confidence interval: 52.2-71.8%) had the right eye was affected. Foreign body positive cultures were achieved in 32.7% (95% confidence interval: 23.7-42.7%) of the cases. The microorganisms isolated from the foreign body culture were identified as: Streptococcus, alpha-hemolytic (n=4), Staphylococcus aureus (n=4), Staphylococcus, coagulase-negative (n=4), Corynebacterium xerosis (n=3), unidentified Gram-positive bacillus (n=2), Moraxella sp (n=1), Serratia sp (n=1), Acynetobacter sp (n=1). The microbial sensitivity test showed that 95% of the cases were sensitive to chloramphenicol and 90% were sensitive to ciprofloxacin, these being antibiotics used in our routine service. CONCLUSION: Superficial corneal foreign body acts as important contaminant vector and the great majority of isolated bacteria were sensitive to the antibiotic prophylaxis used in the treatment.