A genomic approach to understand interactions between Streptococcus pneumoniae and its bacteriophages

BMC Genomics

Table 1 Sensitivity of S. pneumoniae strains to bacteriophages SOCP and Dp-1

S. pneumoniae strains	cps2C status^a	Capsule^b	Phages
			SOCP		Dp-1
			Phage titer (PFU/mL)	EOP^c	Phage titer (PFU/mL)	EOP^c
R6	NA	-	10⁹	1	10¹⁰	1
D39	WT	+	0	NA	0	NA
D39^Δcps2C	KO	-	10⁹	1	10¹⁰	1
D39^cps2C-rspL	WT	+	0	NA	0	NA
R6-SOCP^R	NA	-	1	10⁻⁹	10¹⁰	1
R6-DP1^R	NA	-	10⁹	1	10²	10⁻⁸

^aWT, S. pneumoniae D39 wild type allele; KO, S. pneumoniae D39 allele inactivated by insertion-duplication mutagenesis; NA, Not applicable since the gene is absent in S. pneumoniae R6 due to the deletion of the capsule locus [77, 78]
^b‘+’ and ‘-’ respectively indicate the presence and absence of the pneumococcal capsule as determined by the Quellung reaction (see Fig. 1)
^cEOP, efficiency of plaquing. Represents the ratio of phage titers from the test strain to the indicator strain S. pneumoniae R6 WT. Measured from three independent triplicates. NA, not applicable because of absolute bacteriophage resistance

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