TY - JOUR
T1 - CRISPR interference can prevent natural transformation and virulence acquisition during in vivo bacterial infection
AU - Bikard, David
AU - Hatoum-Aslan, Asma
AU - Mucida, Daniel
AU - Marraffini, Luciano A.
N1 - Funding Information:
We are indebted to Alexander Tomasz, Vincent Fischetti, and Chad Euler for providing strains. We thank Bernardo Reis for experimental assistance, Frederico Costa-Pinto for colony photography, and members of our laboratory for critical reading of the manuscript. We thank Jean-Pierre Claverys for pCEP plasmid. D.B. is supported by a Harvey L. Karp Discovery Award and the Bettencourt Schuller Foundation. D.M. is supported by an Ellison Medical Foundation New Scholar Award in Aging. L.A.M. is supported by the Searle Scholars Program and an Irma T. Hirschl award. L.A.M. conceived and supervised this study. D.B. and L.A.M. designed experiments. L.A.M. constructed strains. D.B. performed in vitro transformation and animal experiments. D.M. obtained anti-pneumococcal serum. A.H.-A. performed primer extension analysis. L.A.M. and D.B. wrote the paper.
PY - 2012/8/16
Y1 - 2012/8/16
N2 - Pathogenic bacterial strains emerge largely due to transfer of virulence and antimicrobial resistance genes between bacteria, a process known as horizontal gene transfer (HGT). Clustered, regularly interspaced, short palindromic repeat (CRISPR) loci of bacteria and archaea encode a sequence-specific defense mechanism against bacteriophages and constitute a programmable barrier to HGT. However, the impact of CRISPRs on the emergence of virulence is unknown. We programmed the human pathogen Streptococcus pneumoniae with CRISPR sequences that target capsule genes, an essential pneumococcal virulence factor, and show that CRISPR interference can prevent transformation of nonencapsulated, avirulent pneumococci into capsulated, virulent strains during infection in mice. Further, at low frequencies bacteria can lose CRISPR function, acquire capsule genes, and mount a successful infection. These results demonstrate that CRISPR interference can prevent the emergence of virulence in vivo and that strong selective pressure for virulence or antibiotic resistance can lead to CRISPR loss in bacterial pathogens.
AB - Pathogenic bacterial strains emerge largely due to transfer of virulence and antimicrobial resistance genes between bacteria, a process known as horizontal gene transfer (HGT). Clustered, regularly interspaced, short palindromic repeat (CRISPR) loci of bacteria and archaea encode a sequence-specific defense mechanism against bacteriophages and constitute a programmable barrier to HGT. However, the impact of CRISPRs on the emergence of virulence is unknown. We programmed the human pathogen Streptococcus pneumoniae with CRISPR sequences that target capsule genes, an essential pneumococcal virulence factor, and show that CRISPR interference can prevent transformation of nonencapsulated, avirulent pneumococci into capsulated, virulent strains during infection in mice. Further, at low frequencies bacteria can lose CRISPR function, acquire capsule genes, and mount a successful infection. These results demonstrate that CRISPR interference can prevent the emergence of virulence in vivo and that strong selective pressure for virulence or antibiotic resistance can lead to CRISPR loss in bacterial pathogens.
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U2 - 10.1016/j.chom.2012.06.003
DO - 10.1016/j.chom.2012.06.003
M3 - Article
C2 - 22901538
AN - SCOPUS:84865144676
SN - 1931-3128
VL - 12
SP - 177
EP - 186
JO - Cell Host and Microbe
JF - Cell Host and Microbe
IS - 2
ER -