title: Molecular Analysis of Rising Fluoroquinolone Resistance in Belgian Non-Invasive Streptococcus pneumoniae Isolates (1995-2014).
abstract: We present the results of a longitudinal surveillance study (1995-2014) on fluoroquinolone resistance (FQ-R) among Belgian non-invasive Streptococcus pneumoniae isolates (n = 5,602). For many years, the switch to respiratory fluoroquinolones for the treatment of (a)typical pneumonia had no impact on FQ-R levels. However, since 2011 we observed a significant decrease in susceptibility towards ciprofloxacin, ofloxacin and levofloxacin with peaks of 9.0%, 6.6% and 3.1% resistant isolates, respectively. Resistance to moxifloxacin arised sporadically, and remained <1% throughout the entire study period. We observed classical topoisomerase mutations in gyrA (n = 25), parC (n = 46) and parE (n = 3) in varying combinations, arguing against clonal expansion of FQ-R. The impact of recombination with co-habiting commensal streptococci on FQ-R remains marginal (10.4%). Notably, we observed that a rare combination of DNA Gyrase mutations (GyrA_S81L/GyrB_P454S) suffices for high-level moxifloxacin resistance, contrasting current model. Interestingly, 85/422 pneumococcal strains display MICCIP values which were lowered by at least four dilutions by reserpine, pointing at involvement of efflux pumps in FQ-R. In contrast to susceptible strains, isolates resistant to ciprofloxacin significantly overexpressed the ABC pump PatAB in comparison to reference strain S. pneumoniae ATCC 49619, but this could only be linked to disruptive terminator mutations in a fraction of these. Conversely, no difference in expression of the Major Facilitator PmrA, unaffected by reserpine, was noted between susceptible and resistant S. pneumoniae strains. Finally, we observed that four isolates displayed intermediate to high-level ciprofloxacin resistance without any known molecular resistance mechanism. Focusing future molecular studies on these isolates, which are also commonly found in other studies, might greatly assist in the battle against rising pneumococcal drug resistance.
authors.affiliation: Unit of Bacterial Diseases, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Pieter-Jan
authors.initials: PJ
authors.lastname: Ceyssens
authors.affiliation: Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université Catholique de Louvain, 1200 Brussels, Belgium.
authors.forename: Françoise
authors.initials: F
authors.lastname: Van Bambeke
authors.affiliation: Unit of Bacterial Diseases, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Wesley
authors.initials: W
authors.lastname: Mattheus
authors.affiliation: Unit of Bacterial Diseases, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Sophie
authors.initials: S
authors.lastname: Bertrand
authors.affiliation: Unit of Bacterial Diseases, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Fux
authors.affiliation: Unit of Bacterial Diseases, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Eddie
authors.initials: E
authors.lastname: Van Bossuyt
authors.affiliation: Unit of Bacterial Diseases, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Damée
authors.affiliation: Unit of Foodborne Pathogens, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Henry-Jean
authors.initials: HJ
authors.lastname: Nyssen
authors.affiliation: Unit of Foodborne Pathogens, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Stéphane
authors.initials: S
authors.lastname: De Craeye
authors.affiliation: Laboratory of Clinical Bacteriology and Mycology, KULeuven, 3000 Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Verhaegen
authors.affiliation: Pharmacologie cellulaire et moléculaire, Louvain Drug Research Institute, Université Catholique de Louvain, 1200 Brussels, Belgium.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Tulkens
authors.affiliation: Unit of Bacterial Diseases, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium.
authors.forename: Raymond
authors.initials: R
authors.lastname: Vanhoof
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000235:genetics*; D001530:Belgium / Q000453:epidemiology; D027081:DNA Gyrase / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000187:drug effects / Q000235:genetics*; D005260:Female; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D020125:Mutation, Missense; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics; D013296:Streptococcus pneumoniae / Q000235:genetics / Q000302:isolation & purification
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D024841:Fluoroquinolones; D027081:DNA Gyrase