Table 1

Genetic alterations in HaitiV, a live attenuated cholera vaccine.

MutationRationale
ΔCTXΦAttenuates by removing the genes encoding
CT and the multifunctional toxin MARTX
(13); protects against toxigenic reversion
by preventing chromosomal integration of
CTXΦ (12)
ΔflaBDEflaACAttenuates and reduces potential
reactogenicity (15)
ΔfloR-strAB-sul2dfrAPrevents the dispersal of antibiotic resistance
genes
N900_11550::Phtpg-ctxBConstitutive expression of CtxB (fig. S1)
promotes anti-CtxB immune responses
that may protect against diarrheal disease
caused by V. cholerae and ETEC (16)
ΔhupBProtects from toxigenic reversion by
inactivating the HU complex, which is
necessary for extrachromosomal
replication of CTXΦ (14)
lacZ::cas9-sgRNA_ctxAEndonuclease targeting of ctxA prevents
toxigenic reversion
ΔrecAPrevents homologous recombination-
dependent gene acquisition