OBJECTIVES: Limited data exist regarding the role of agr dysfunction in reducing susceptibility to vancomycin in methicillin-susceptible Staphylococcus aureus (MSSA). This study investigated the clinical and molecular epidemiology of MSSA causing bacteraemia, with emphasis on the reduced susceptibility to vancomycin (RSV) phenotype (MIC ≥ 1.5 mg/L) and its relationship with agr dysfunction. METHODS: All MSSA bloodstream isolates obtained at our hospital during 2010 were analysed. Antimicrobial susceptibility was determined and time-kill experiments were performed for oxacillin. Multilocus sequence type and agr genotype were determined and DNA microarray analysis of virulence factors was performed. agr dysfunction was assessed phenotypically and by RT-PCR quantification of RNAIII. RESULTS: Of 84 MSSA, 55 (65.5%) exhibited the RSV phenotype, comprising 13 clonal complexes. agr II polymorphism was more prevalent in RSV than non-RSV isolates (41.8% versus 17.2%, P = 0.023) and average levels of RNAIII gene expression were higher in RSV than non-RSV isolates (ΔCt 4.05 ± 3.29 versus 1.5 ± 2.11, P = 0.005), implying greater agr dysfunction in RSV MSSA. CONCLUSIONS: We demonstrated a correlation between RSV phenotype in MSSA and reduced agr expression, particularly in association with the agr II genotype. These results may help to understand the role of agr dysfunction in the increased mortality in MSSA infections.
OBJECTIVES: Limited data exist regarding the role of agr dysfunction in reducing susceptibility to vancomycin in methicillin-susceptible Staphylococcus aureus (MSSA). This study investigated the clinical and molecular epidemiology of MSSA causing bacteraemia, with emphasis on the reduced susceptibility to vancomycin (RSV) phenotype (MIC ≥ 1.5 mg/L) and its relationship with agr dysfunction. METHODS: All MSSA bloodstream isolates obtained at our hospital during 2010 were analysed. Antimicrobial susceptibility was determined and time-kill experiments were performed for oxacillin. Multilocus sequence type and agr genotype were determined and DNA microarray analysis of virulence factors was performed. agr dysfunction was assessed phenotypically and by RT-PCR quantification of RNAIII. RESULTS: Of 84 MSSA, 55 (65.5%) exhibited the RSV phenotype, comprising 13 clonal complexes. agr II polymorphism was more prevalent in RSV than non-RSV isolates (41.8% versus 17.2%, P = 0.023) and average levels of RNAIII gene expression were higher in RSV than non-RSV isolates (ΔCt 4.05 ± 3.29 versus 1.5 ± 2.11, P = 0.005), implying greater agr dysfunction in RSV MSSA. CONCLUSIONS: We demonstrated a correlation between RSV phenotype in MSSA and reduced agr expression, particularly in association with the agr II genotype. These results may help to understand the role of agr dysfunction in the increased mortality in MSSA infections.
Entities:
Keywords:
MSSA; RSV; reduced susceptibility to vancomycin
Authors: Danielle N Atwood; Karen E Beenken; Allister J Loughran; Daniel G Meeker; Tamara L Lantz; Justin W Graham; Horace J Spencer; Mark S Smeltzer Journal: Infect Immun Date: 2016-03-24 Impact factor: 3.441
Authors: J M Pericàs; J A Messina; C Garcia-de-la-Mària; L Park; B K Sharma-Kuinkel; F Marco; D Wray; Z A Kanafani; M Carugati; E Durante-Mangoni; P Tattevin; V H Chu; A Moreno; V G Fowler; J M Miró Journal: Clin Microbiol Infect Date: 2017-02-01 Impact factor: 8.067
Authors: Justin R Lenhard; Tanya Brown; Michael J Rybak; Calvin J Meaney; Nicholas B Norgard; Zackery P Bulman; Daniel A Brazeau; Steven R Gill; Brian T Tsuji Journal: Antimicrob Agents Chemother Date: 2015-12-28 Impact factor: 5.191
Authors: Eric Y Kok; Jesus G Vallejo; Lauren M Sommer; Louie Rosas; Sheldon L Kaplan; Kristina G Hulten; J Chase McNeil Journal: Antimicrob Agents Chemother Date: 2018-04-26 Impact factor: 5.191
Authors: Natasha E Holmes; John D Turnidge; Wendy J Munckhof; J Owen Robinson; Tony M Korman; Matthew V N O'Sullivan; Tara L Anderson; Sally A Roberts; Sanchia J C Warren; Geoffrey W Coombs; Hui-Leen Tan; Wei Gao; Paul D R Johnson; Benjamin P Howden Journal: J Clin Microbiol Date: 2014-07-16 Impact factor: 5.948
Authors: J Chase McNeil; Eric Y Kok; Andrea R Forbes; Linda Lamberth; Kristina G Hulten; Jesus G Vallejo; Edward O Mason; Sheldon L Kaplan Journal: Pediatr Infect Dis J Date: 2016-03 Impact factor: 2.129
Authors: Juan M Pericàs; Carlos Cervera; Cristina Garcia-de-la-Mària; Batu K Sharma-Kuinkel; Rachelle Gonzales; Asunción Moreno; Manel Almela; Carlos Falces; Eduard Quintana; David Fuster; Francesc Marco; Arnold S Bayer; Vance G Fowler; José M Miró Journal: Antimicrob Agents Chemother Date: 2020-02-21 Impact factor: 5.191