Different VISA phenotypes selected from the same ST100-hVISA parental strain

DI GREGORIO S; FERNÁNDEZ S; CUIROLO A; VERLAINE O; AMOROSO A; MENGIN- LECREULX D; FAMIGLIETTI A; JORIS B; MOLLERACH M

MICROBIAL DRUG RESISTANCE-MECHANISMS EPIDEMIOLOGY AND DISEASE

MARY ANN LIEBERT INC

Lugar: New York; Año: 2017 vol. 23

1076-6294

The aim of this study is to characterize the factors related to peptidoglycan metabolism in isogenic hVISA/VISA ST100 strains. Recently we reported the increase in IS256 transposition in invasive hVISA ST100 clinical strains isolated from the same patient (D1 and D2) before and after vancomycin treatment and two laboratory VISA mutants (D23C9 and D2P11) selected from D2 in independent experiments.HPLC-MS analysis of peptidoglycan muropeptides showed increased proportion of monomericmuropeptides and a concomitant decrease in the proportion of tetrameric muropeptide in D2 and derived mutants when compared to the original strain D1. Additionally, strain D2 and its derived mutants showed an increase in cell wall thickness with increased in pbp2 gene expression. The VISA phenotype was not stable in D2P11 and showed a reduced autolysis profile. On the other hand, the mutant D23C9 differentiates from D2 and D2P11 in the autolysis profile, and pbp4 transcription profile.D2 derived mutants exhibited differences in the susceptibility to other antimicrobials. Our results highlight the possibility of selection of different VISA phenotypes from a single genetic background.