(Phys.org)A Kansas State University research team has resolved a 40-year-old debate on the role of iron acquisition in bacterial invasion of animal tissues.

The collaborative researchled by Phillip Klebba, professor and head of the department of biochemistryclarifies how microorganisms colonize animal hosts and how scientists may block them from doing so. The findings suggest new approaches against bacterial disease and new strategies for antibiotic development.

The studyin collaboration with Tyrrell Conway, director of the Microarray and Bioinformatics Core Facilities at the University of Oklahoma, and Salete M. Newton, Kansas State University research professor of biochemistryrecently appeared in PLOS ONE. It shows how iron acquisition affects the ability of bacteria to colonize animals, which is the first stage of microbial disease.

"This paper establishes that iron uptake in the host is a crucial parameter in bacterial infection of animals," said Klebba, the senior author on the publication. "The paper explains why discrepancies exist about the role of iron, and it resolves them."

Iron plays a key role in metabolism, leading bacteria and animals to battle each other to obtain it. Klebba's team found that E. coli must acquire iron from the host to establish a foothold and colonize the guta concept that was often debated by scientists.

"For years it was theorized that iron is a focal point of bacterial pathogenesis and infectious disease because animals constantly defend the iron in their bodies," Klebba said. "Animal proteins bind iron and prevent microorganisms from obtaining it. This is called nutritional immunity, and it's a strategy of the host defense system to minimize bacterial growth. But successful pathogens overcome nutritional immunity and get the iron."

Little was known about what forms of iron enteric bacteriawhich are bacteria of the intestinesuse when growing in the host, but this study shows that the native Gram-negative bacterial iron uptake systems are highly effective. Scientists questioned whether prevention of iron uptake could block bacterial pathogenesis. This article leaves no doubt about the importance of iron when E. coli colonizes animals because bacteria that were systematically deprived of iron became 10,000-fold less able to grow in host tissues, Klebba said.

"This is the first time our experiments unambiguously verified the indispensability of iron in infection, because here we created the correct combination of mutations to study the problem," Klebba said.

Enteric bacteria have so many iron transport systems that it's difficult to eliminate them all. For example, E. coli has at least eight iron acquisition systems.

"These transporters are redundant because iron is essential," Klebba said. "Bacteria are resilient. If one system is blocked, then another one takes over."

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Battling bacteria: Research shows iron's importance in infection, suggests new therapies