%0 Journal Article
%T Comparison of different culture media and storage temperatures for the long-term preservation of Streptococcus pneumoniaein the tropics
%A Siberry
%A George
%A Brahmadathan
%A K.N.
%A Pandian
%A Rajeswar
%A Lalitha
%A M.K.
%A Steinhoff
%A Mark C.
%A John
%A T. Jacob
%J Bulletin of the World Health Organization
%D 2001
%I World Health Organization
%R 10.1590/S0042-96862001000100009
%X objective: the preservation of streptococcus pneumoniae by standard freezing methods for subsequent tests - such as serotyping and antibiotic susceptibility - is not possible or is difficult in many developing countries because of the high cost of equipment, inadequate equipment maintenance, and irregular power supply. we evaluated alternative low-cost methods, by comparing different culture media and storage temperatures. methods: clinical isolates of five capsular types (1, 5, 7, 19, and 23) of s. pneumoniae were preserved in rabbit blood, sheep blood, skimmed milk, or glycerol-chocolate broth, and stored at -20 oc or -70 oc. the cultures were also preserved by lyophilization or sand desiccation, followed by storage at room temperature and 4 oc. the viability of the preserved cultures was determined by making serial colony counts on day 0 and after 1 week, 4 weeks, 4 months and 16 months. the viability of cultures preserved by sand desiccation and storage at 4 oc was also determined every 6 months for up to 68 months. findings: irrespective of the media used, cultures maintained at -20 oc became nonviable by the fourth month, while those maintained at -70 oc were still viable at 16 months. cultures preserved by lyophilization or sand desiccation lost their viability by the fourth month when maintained at local room temperature (30-42 oc), but remained viable when stored at 4 oc for up to 68 months. conclusion: our results confirm that freezing at -70 oc, or lyophilization and storage at 4 oc are the ideal methods for the preservation of s. pneumoniae. in laboratories where lyophilization is not feasible, sand desiccation and storage at 4 oc offers an alternative low-cost method for the long-term preservation of s. pneumoniae.
%K streptococcus pneumoniae [preservation]
%K culture media
%K cryopreservation [methods]
%K lyophilization [methods]
%K desiccation [methods]
%K tropical climate.
%U http://www.scielosp.org/scielo.php?script=sci_abstract&pid=S0042-96862001000100009&lng=en&nrm=iso&tlng=en