Resumo

GUTIERREZ, Clara Nancy et al. Pharingeal isolation of betahaemolithic streptococci using Todd-Hewitt broth in asymptomatic individuals with and without previous dental brushing. Saber [online]. 2014, vol.26, n.3, pp.265-272. ISSN 1315-0162.

Beta-hemolytic streptococci are bacteria capable to inflict serious pathologies and leave permanent consequences, particularly in the children population. The pharyngeal exudate and posterior isolation in blood agar is the most common method used for their identification. Currently, it has been observed that some researchers recommend not to brush the teeth before the completion of the throat swab while some authors recommend brushing the teeth before the test. In consequence, the objective of the present study was to determine the isolation of these bacteria using Todd-Hewitt broth in asymptomatic individuals with and without dental brushing. The sample was a group of 203 asymptomatic children within the age 10 to 15 years old, of both sexes, enrolled in four schools from "Francisco Linares Alcántara" Municipality, Aragua State, Venezuela. The group of beta-hemolytic streptococci most often isolated corresponded to the group G (42%). The number of beta-hemolytic streptococci isolations was significantly higher (p = 0.0011) in the group who had not brushed their teeth (n = 17/104) in comparison with the group of youths who did (n = 2/99). The incubation on the cotton swab corresponding to the pharyngeal exudate in Todd Hewitt broth before the inoculation on the Blood Agar, favored noticeably the recuperation of beta-hemolytic streptococci compared with the technique of direct seeding the swab on blood agar. A weak agreement was found in the concordance strength (κ = 0.16943) between the used techniques and there were statistically significant differences between the number of beta-hemolytic streptococci isolations through the execution of both procedures (18 vs. 3; p =0.02060). These findings demonstrate that the no-teeth-brushing and the previous incubation of the swab? in Todd Hewitt broth enhances the isolation of these microorganisms.

Palavras-chave : Streptococcus pyogenes; throat swab; teeth brushing; Todd-Hewitt’s broth.

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