Johnson, S. R.Grad, YonatanGanakammal, S. R.Burroughs, M.Frace, M.Lipsitch, MarcWeil, R.Trees, D.2016-05-032014Johnson, S. R., Y. Grad, S. R. Ganakammal, M. Burroughs, M. Frace, M. Lipsitch, R. Weil, and D. Trees. 2014. “In Vitro Selection of Neisseria Gonorrhoeae Mutants with Elevated MIC Values and Increased Resistance to Cephalosporins.” Antimicrobial Agents and Chemotherapy 58 (11) (September 8): 6986–6989. doi:10.1128/aac.03082-14. http://dx.doi.org/10.1128/AAC.03082-14.0066-4804http://nrs.harvard.edu/urn-3:HUL.InstRepos:26883711Strains of Neisseria gonorrhoeae with mosaic penA genes bearing novel point mutations in penA have been isolated from ceftriaxone treatment failures. Such isolates exhibit significantly higher MIC values to third-generation cephalosporins. Here we report the in vitro isolation of two mutants with elevated MICs to cephalosporins. The first possesses a point mutation in the transpeptidase region of the mosaic penA gene, and the second contains an insertion mutation in pilQ.en-USanti-bacterial agents/pharmacology*cephalosporins/pharmacology*drug resistance, multiple, bacterial*/geneticserythromycin/pharmacologyfimbriae proteins/genetics*gonorrhea/drug therapygonorrhea/microbiologyhumansmicrobial sensitivity testsmolecular sequence datamutationneisseria gonorrhoeae/drug effects*neisseria gonorrhoeae/genetics*neisseria gonorrhoeae/isolation & purificationpenicillin-binding proteins/geneticstreatment failurebeta-lactamases/genetics*Journal Article2016-05-0310.1128/AAC.03082-14