21Extraintestinal pathogenic Escherichia coli (ExPEC) are major causes of urinary and 22 bloodstream infections. ExPEC reservoirs are not completely understood. Some mastitis-23 associated E. coli (MAEC) strains carry genes associated with ExPEC virulence, including metal 24 scavenging, immune avoidance, and host attachment functions. In this study, we investigated the 25 role of the high-affinity zinc uptake (znuABC) system in the MAEC strain M12. Elimination of 26 znuABC moderately decreased fitness during mouse mammary gland infections. The znuABC 27 mutant strain exhibited an unexpected growth delay in the presence of bile salts, which was 28 alleviated by the addition of excess zinc. We isolated znuABC mutant suppressor mutants with 29 improved growth of in bile salts, several of which no longer produced the K96 capsule made by 30 strain M12. Addition of bile salts also reduced capsule production by strain M12 and ExPEC 31 strain CP9, suggesting that capsule synthesis may be detrimental when bile salts are present. To 32 better understand the role of the capsule, we compared the virulence of mastitis strain M12 with 33 its unencapsulated kpsCS mutant in two models of ExPEC disease. The wild type strain 34 successfully colonized mouse bladders and kidneys and was highly virulent in intraperitoneal 35 infections. Conversely, the kpsCS mutant was unable to colonize kidneys and was unable to 36 cause sepsis. These results demonstrate that some MAEC may be capable of causing human 37 ExPEC illness. Virulence of strain M12 in these infections is dependent on its capsule. However, 38 capsule may interfere with zinc homeostasis in the presence of bile salts while in the digestive 39 tract. 40 41 42 43
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.