ABCG2 and bacterial infectious disease: In conclusion, MsmK is identified as an ATPase functioning as a key component of ABC transporters in S. suis. It is essential not only for the utilization of multiple carbohydrates including raffinose, melibiose, maltotetraose, glycogen and maltotriose, but also for the ability of in vivo survival and colonization of S. suis. Awareness of the important roles of carbohydrate utilization during the growth and infection of pathogenic bacteria may lead to new strategies to combat bacterial infectious diseases.