RESUMO
An in-vitro study was undertaken to investigate the survival on bacteriological swabs of three potentially pathogenic organisms found in oro-facial infections, by using simulated clinical specimens incubated in the presence or absence of Amies transport medium. Standard inocula of pure cultures of Streptococcus milleri, Prevotella melaninogenica and Peptostreptococcus anaerobius were soaked on to swabs and plated out on to solid media at various intervals up to 3 days, enabling an estimate of their viability to be made following further incubation. Differential survival of the three test organisms was observed, with Streptococcus milleri being generally the hardiest and Peptostreptococcus anaerobius the least hardy, whilst survival was consistently enhanced by the presence of a transport medium. Recovery of Prevotella melaninogenica was improved by incubation for 5 days. We conclude that transport swabs should be used in preference to plain swabs whenever immediate laboratory culture cannot be assured, to avoid loss of anaerobic bacteria.
