a decreasing trendP < 0.0001
Pairwise reduction curves showed a decreasing trend on transitioning from Serotype I to II ( P < 0.0001) in 34/48 (70.8%) samples, from Serotype I to III ( P = 0.0281) in 30/48 (62.5%) samples, and from Serotype I to IV ( P < 0.0001) in 38/48 (79.2%) samples ( Figure 5 (C)).