Spread of Klebsiella pneumoniae ST395 non-susceptible to carbapenems and resistant to fluoroquinolones in North-Eastern France

Objectives: Fluoroquinolones (FQs) are a potential treatment for infections caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae that are susceptible to these agents. Methods: Owing to increasing non-susceptibility to carbapenems among Enterobacteriaceae, in this study FQ resistance mechanisms were characterised in 36 ertapenem-non-susceptible Klebsiella pneumoniae isolated from North-Eastern France in 2012. The population structure was described by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Results: Among the 36 isolates, 13 (36%) carried a carbapenemase encoding-gene. Decreased expression of the OmpK35-encoding gene might be considered a major resistance determinant that could explain the non-susceptibility to carbapenems. The carbapenemase-producing isolates carried the well-known IncL pOXA-48a plasmid. All 36 K. pneumoniae isolates also harboured a FQ resistance determinant. The aac(6')-Ib-cr gene was the major plasmid-mediated quinolone resistance (PMQR) determinant found in K. pneumoniae (89%; 32/36). MLST identified five sequence types (STs), with the most common being ST395 (69%; 25/36), followed by ST147 (17%; 6/36). ST395 strains showed ertapenem minimum inhibitory concentrations (MICs) ranging from 0.75-32 mu g/mL. Klebsiella pneumoniae ST395 isolates did not show enhanced biofilm formation or environmental survival but showed higher chlorhexidine MICs compared with ST147 isolates. Conclusions: These findings showed that (i) K. pneumoniae ST395 carrying pOXA-48a has spread in North-Eastern France, (ii) aac(6')-Ib-cr is predominant in carbapenem-non-susceptible K. pneumoniae, (iii) K. pneumoniae ST395 is resistant to chlorhexidine and (iv) FQs as an alternative to beta-lactams to treat ertapenem-non-susceptible K. pneumoniae are compromised. (C) 2017 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.