title: In vitro antimicrobial susceptibility of Helcococcus kunzii and molecular analysis of macrolide and tetracycline resistance.
abstract: Thanks to the recent advent of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) technology, Helcococcus kunzii is now easily identifiable and considered as an opportunistic pathogen. However, data about antimicrobial susceptibilities remain very limited. The aim of the study was, then, to assess its in vitro susceptibility to 18 antimicrobial agents and to investigate the genetic basis of macrolide and tetracycline resistance. Thirty-nine human clinical isolates of H. kunzii collected from 2008 to 2013 were studied, as well as the type strain ATCC 51366(T). Minimum inhibitory concentrations (MICs) of penicillin G, amoxicillin, cefotaxime, imipenem, gentamicin, erythromycin, clindamycin, quinupristin-dalfopristin, ciprofloxacin, levofloxacin, tetracycline, tigecycline, vancomycin, teicoplanin, linezolid, daptomycin, cotrimoxazole and rifampin were determined by the microdilution method. Screening for macrolide [erm(A) including erm(TR), erm(B), erm(C), erm(F), erm(T), erm(X), msr(A) and mef(A)] and tetracycline [tet(L), tet(M) and tet(O)] resistance genes was performed, as well as the detection of mutations in 23S rRNA. Except for one strain resistant to cefotaxime, all strains were categorised as susceptible to β-lactams, glycopeptides, linezolid, daptomycin and tigecycline. Whereas ciprofloxacin and gentamicin exhibited limited activity, 95% of strains were categorised as susceptible to levofloxacin. Concerning erythromycin, a bimodal distribution was observed, with 29 'wild-type' strains (MICs from 0.25 to 2 mg/L) and 11 'resistant' strains (MICs ≥ 256 mg/L), including ten harbouring erm(TR). Two isolates exhibited acquired tetracycline resistance (MICs of 16 mg/L) by the production of tet(M). This large study on the in vitro antimicrobial susceptibility of H. kunzii suggests that β-lactams (especially penicillins) should be preferred for the treatment.
authors.affiliation: Laboratoire de Biologie, CH de Cahors, Cahors, France.
authors.forename: A
authors.initials: A
authors.lastname: Vergne
authors.affiliation: Service de Microbiologie & CNR de la Résistance aux Antibiotiques, CHU de Caen, Caen, France.|Université de Caen Basse-Normandie, EA4655 (équipe "Antibio-résistance"), Caen, France.
authors.forename: F
authors.initials: F
authors.lastname: Guérin
authors.affiliation: ADMED Microbiologie, La Chaux-de-Fonds, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Lienhard
authors.affiliation: Laboratoire de Biologie, CH de Cahors, Cahors, France.
authors.forename: A
authors.initials: A
authors.lastname: Le Coustumier
authors.affiliation: Service de Microbiologie & CNR de la Résistance aux Antibiotiques, CHU de Caen, Caen, France.
authors.forename: C
authors.initials: C
authors.lastname: Daurel
authors.affiliation: Service de Microbiologie & CNR de la Résistance aux Antibiotiques, CHU de Caen, Caen, France.|Université de Caen Basse-Normandie, EA4655 (équipe "Antibio-résistance"), Caen, France.
authors.forename: C
authors.initials: C
authors.lastname: Isnard
authors.affiliation: Service de Bactériologie-Hygiène, CHU de Toulouse, Toulouse, France.
authors.forename: N
authors.initials: N
authors.lastname: Marty
authors.affiliation: Service de Bactériologie & CNR des Streptocoques, GH Cochin-Hôtel Dieu-Broca, Assistance Publique-Hôpitaux de Paris, Paris, France.
authors.forename: C
authors.initials: C
authors.lastname: Poyart
authors.affiliation: Service de Microbiologie & CNR de la Résistance aux Antibiotiques, CHU de Caen, Caen, France. cattoir-v@chu-caen.fr.|Université de Caen Basse-Normandie, EA4655 (équipe "Antibio-résistance"), Caen, France. cattoir-v@chu-caen.fr.
authors.forename: V
authors.initials: V
authors.lastname: Cattoir
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D000068536:Bacillota / Q000187:drug effects* / Q000235:genetics*; D005602:France; D006801:Humans; D018942:Macrolides / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D013557:Switzerland; D013753:Tetracycline Resistance / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D018942:Macrolides