Comparative evaluation of sheep blood agar and human blood agar in the isolation of beta hemolitic Streptococcus of patients with pharyngitis from Almanzor Aguinaga Asenjo hospital of Chiclayo, Perú. 2006

Abstract

It were evaluated comparatively sheep blood agar and human blood agar, in the isolation of beta hemolytic Streptococcus of patients from Almanzor Aguinaga Asenjo from Chiclayo between January and December of 2006. The investigation was realized with 242 samples of patients with pharyngitis, every sample was scattered in three plates with human blood agar and in three plates with sheep blood agar. The plates with both mediums were distributed to be incubated paralelaly in three different atmospheres: in aerobiosis, with 5% of CO and in 2 anaerobiosis. The macroscopic and microscopically colonies compatible with Streptococcus genus it was realized the catalasa test, and them it was cultivated in Todd – Hewitt broth. The isolations were identified as beta hemolytic Streptococcus by the Lancefield Precipitation method, using specificity well known group serum. The comparative evaluation of the used culture mediums demonstrate that, human blood agar allow the isolation of beta hemolytic Streptococcus as well as sheep blood agar; although it does not find a significantly difference in the frequency of isolation between both culture mediums. It was found also that the anaerobic incubation allows a high number of isolations of beta hemolytic Streptococcus as well as in human blood agar and sheep blood agar. It was determined also that the incubation by 48 hours allows a high number of isolations in both mediums.