TABLE 1.

Methodological differences between Streptococcus pneumoniae carriage studies conducted in the Netherlands and in England.

Processing step	The Netherlands	England
Transport medium	1 ml Amies	1 ml STGG
Transport temperature	Ambient	2–8°C
Duration of transport	<8 h	<48 h
Arrival to the diagnostic lab	Culturing on receipt	Storage at −80°C
Culture medium	BA-GENT and CBA	COBA and CBA
Inoculum volume	35 μl	50 μl
Identification of S. pneumoniae	Optochin-susceptibility and bile solubility tests	Bioinformatics-based method applied to bacterial DNA
Minimally processed (MP) sample	An aliquot of Amies stored at −80°C	An aliquot of skim milk tryptone glucose and glycerine broth medium (STGG) stored at −80°C
Culture-enriched (CE) sample	Whole BA-GENT plate colony growth washed with 2.1 ml of BHI with 10%glycerol	Swab of α-hemolytic colonies from COBA (first choice) or CBA, and into 1 ml of STGG

STGG, skim milk tryptone glucose and glycerine broth medium; CBA, Columbia blood agar plate; BA-GENT, blood agar plate gentamycin; COBA, blood agar plate with Streptococcus selective medium.