Biofilm formation in Gardnerella vaginalis
Gardnerella vaginalis is the causative agent of bacterial vaginosis, the most common vaginal infection. Biofilm formation by G. vaginalis is necessary for the pathogenesis of bacterial vaginosis. MADELINE and colleagues conducted an evolve and re-sequence experiment in the laboratory, selecting for biofilm formation by G. vaginalis. They observed increased biofilm formation and increased cell aggregation. Whole-genome sequencing was conducted in order to measure changes in allele frequency in response to the selective pressure. MADELINE observed convergent adaptation at a number of loci which may be important for biofilm formation in Gardnerella vaginalis.
Antibiotic resistance in C. difficile
Clostridiodes difficile causes severe enteric infection. Emergent spread of a new clone that is resistant to metronidazole antibiotics has been observed in hospital settings. MADELINE and colleagues conducted a genome-wide association study to determine the genetic basis of metronidazole resistance in C. difficile and found that a SNP in the promotor of nimB was significantly associated with resistance. Interestingly, the presence of this SNP correlated with the presence of a SNP previously shown to confer fluroquinolone resistance.