TABLE 3.

Aggregation of different strains and serotypes of S. pneumoniae by SP-D^a

Strain	Serotype	MLST	No. of clumps/ field of view	Avg area of aggregated bacteria (μm2)
M393	3	260	No clumps	No aggregates
M110	3	180	3.2 ± 0.38	179 ± 0.2
M290	3	49	4.3 ± 0.53	124 ± 0.5
M9	18C	102	5.2 ± 0.50b	156 ± 0.4
M241	18C	113	No clumps	No aggregates
M208	18C	119	No clumps	No aggregates
GM70	19A	81	No clumps	No aggregates
M41	23F	81	4.2 ± 0.37	64 ± 0.1
M322	14A	156	0.7 ± 0.21c	6.1 ± 0.2
M15	9V	156	No clumps	No aggregates
HB565	3	378	3.1 ± 0.20	88 ± 0.6
Ps3205	3	NDd	No clumps	No aggregates
D39	2	128	1.11 ± 0.35	128.62 ± 0.87
Ps3221	3	ND	2.2 ± 0.29	14.2 ± 0.3
G54	19F	63	No clumps	No aggregates

^aPneumococci were incubated with SP-D (10 μg/ml) for 90 min in the presence of calcium (5 mM) and were examined by phase-contrast microscopy (×500). The average area of agglutinated bacteria was measured and was significantly different (P < 0.05) among all aggregated strains. The number of clumps per field of view was determined for aggregated strains. The results are means ± standard errors of the mean of three to five experiments.

^bP < 0.05, significantly higher than other strains.

^cP < 0.05, significantly lower than other strains.

^dND, not determined.