Microbiology

Iron and Virulence

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Science  01 Jun 2001:
Vol. 292, Issue 5522, pp. 1611
DOI: 10.1126/science.292.5522.1611c

Little is known about how Gram-positive bacteria, such as the important human pathogen Streptococcus pneumoniae, acquire iron, a nutrient needed for the growth of pathogens within their hosts. Brown et al. have discovered two loci that encode high-affinity iron transporters in this organism. If both copies of the pit genes were disrupted, then the pathogen could not use hemoglobin as a source of iron, became insensitive to the iron-dependent antibiotic streptonigrin, and lost virulence in a mouse model of infection. The pit2 locus lies within a region of the bacterium's chromosome that has several features of a pathogenicity island, possibly introduced into S. pneumoniae by horizontal transfer from another organism. Such pathogenicity islands have been seen frequently in Gram-negative bacteria but not as yet in Gram-positive S. pneumoniae. — CA

Mol. Microbiol.40, 572 (2001).

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