Growth and survival of Trichomonas vaginalis.
This study confirmed that Feinberg and Whittington medium was suitable for the cultivation and detailed study of the growth cycle of two clinical strains of Trichomonas vaginalis under anaerobic conditions. Both strains showed a similar growth pattern characterised by early but slow growth, extended duration of the logarithmic phase and limited survival never exceeding 144 h. Duration of survival and growth rate were inversely proportional to the inoculum density. Growth rate was pH dependent; pH values in the range 6.9-6.5 delayed the initiation of growth of T. vaginalis for at least 48 h. On the other hand, pH values of 6.4-4.5 were indifferent or slightly favourable for growth during the logarithmic and survival in the early decline phase. Normal saline and Ringer's solution exerted an early and progressively lethal effect on trichomonads and led to the disappearance of protozoa suspended in them in 150 min. In general, these in-vitro results shed light on some aspects of the biology of T. vaginalis and contribute to a better understanding of the epidemiology and clinical manifestations of the infection.