Evaluation of Two Supplemented Culture Media for Long-Term, Room-Temperature Preservation of Streptococcus pneumoniae Strains

Table 3

Viability and contamination of pneumococcal subcultures stored on two supplemented media.

Test	Month	Subcultures on TH-HYC agar			Subcultures on TH-SYC agar
		Contaminated	Evaluated for viability	Viable; %	Contaminated	Evaluated for viability	Viable; %
Test 1 (pilot study); ( = 10 subcultures per medium into plates)	1°	0	10	100	0	10	100
	2°	0	10	100	0	10	100
	3°	2	8	100	3	7	100
	4°	3	7	100	3	7	100
	5°	5	5	100	6	4	100
	6°	7	3	100	8	2	100
Test 2; ( = 50 subcultures per medium into plates)	1°	0	50	100	5	45	100
	2°	9	41	100	14	36	100
	3°	11	39	100	3	17	100
	4°	20	30	100	29	21	100
Test 3; ( = 48 subcultures into microtubes)	2°	3	45	100	NA	NA	NA
Test 4; ( = 48 subcultures into glass tubes)	6°	7	41	100	NA	NA	NA

Subcultures were recorded as viable (at least one visible colony) or nonviable according to the description of Wasas et al., in 1998. with no contamination at the moment of the evaluation. based on the number of cultures with no contamination at the moment of the evaluation. TH-HYC: Todd-Hewitt/Hemoglobin/Yeast/Charcoal. TH-SYC: Todd-Hewitt/Skim-Milk/Yeast/Charcoal. NA: not applicable.