Reduced susceptibility to biocides in XXXX : association with resistance to antimicrobials, epidemiological behaviour, biological cost and effect on the expression of genes encoding porins and efflux pumps.

@entity3082 @entity3403 @entity2177 @entity2888 @entity581 @entity803 @entity71058 @entity3064 @entity3676 @entity5164
OBJECTIVES: The objective of this study was to analyse whether there is an association between reduced susceptibility to biocides in @entity3064 and (i) antimicrobial resistance (co-resistance), (ii) prevalent ( @entity3082 ) clones, (iii) changes in the fitness or (iv) expression of genes related to efflux pumps and porins. METHODS: Susceptibility to biocides and antimicrobials was determined in 49 clonally unrelated isolates of A. baumannii. Biological cost, in terms of mean generation time, was determined by spectrophotometry. Quantitative real-time RT-PCR was used to determine the relative expression of genes encoding several efflux pumps and porins. RESULTS: Reduced susceptibility to @entity5164 , @entity3676 and @entity71058 (  ) was associated with resistance to @entity581 , @entity803 and @entity2177 (P<0.05). The MICs of @entity2888 , @entity581 , @entity3403 and @entity2177 for isolate Ab70 ( @entity3082 clone) exposed to these biocides increased by >= 2 dilutions. Reduced susceptibility to Orsan(  ) was more frequent among prevalent clones than non-prevalent clones (P<0.05). Mean generation times for Ab70 before and after exposure to @entity3676 were 57.8 and 78.1 min, respectively (P=0.02). Relative expression of abeS and adeB was increased in Ab46 and Ab70 after exposure to @entity5164 , but was decreased for ompA and carO after exposure to @entity71058 (  ). CONCLUSIONS: Reduced susceptibility to biocides is associated with co-resistance to carbapenems, @entity581 , @entity803 and @entity2177 . Reduced susceptibility to Orsan(  ) may be a marker of prevalent clones. Acquisition of reduced susceptibility to @entity3676 has a biological cost. Exposure to biocides affects the relative expression of genes related to some efflux pump genes (increased expression) or porins (reduced expression).
