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Mycoplasma (M.) bovis has recently emerged as a major, worldwide etiological agent of bovine respiratory diseases leading to huge economic losses mainly due to high morbidity and mortality as well as poor growth rates. The spread of M. bovis infections between different animals, herds, regions or countries has been often reported to be connected to the movement of animals. However, despite recent considerable efforts, no universal subtyping method is yet available to trace M. bovis isolates circulation at an international scale. Moreover in France, the overall population diversity of M. bovis isolates has not been assessed since the early 1990s. This study was conducted to fill in these gaps. The genotypic diversity between sixty isolates collected in France over the last 35 years was assessed using two molecular subtyping methods that addressed either the long-term epidemiological relationships (Multi Locus Sequence Typing, MLST) or the genetic microvariations (Multiple Locus VNTR Analysis, MLVA) between isolates. Phenotypic diversity was also analyzed by using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) to compare the main protein patterns of isolates. All proposed subtyping approaches were optimized and led to the same pattern in the French M. bovis population that consisted of two clusters, the first one comprising isolates collected before 2000 and the second, those collected after 2000. Recent strains were further shown to be more homogeneous than older ones, which is consistent with the spread of a single clone throughout the country. Because this spread was concomitant with the emergence of multiresistant M. bovis isolates, several hypotheses are discussed to explain the homogeneity of M. bovis isolates in France, even though the M. bovis species is fully equipped to generate diversity.

To the Editor: Melioidosis, a potentially fatal infectious disease, occurs predominantly across much of Asia and in northern Australia because of the soil and water bacterium Burkholderia pseudomallei (1). We report 2 related cases of suppurative cervical lymphadenitis, an unusual adult presentation of melioidosis, in 2 men who returned to France from Vietnam on the same trip (2).

In 2015, the French Armed Forces deployed a biosafety level 3 (BSL3) field laboratory as a part of an Ebola treatment center in Guinea. When closing the center, laboratory decontamination operations were necessary. We present the decontamination protocols applied for the BSL3 field laboratory, making the entire module ready for a future use.

Burkholderia is a bacterial genus comprising several pathogenic species, including two species highly pathogenic for humans, B. pseudomallei and B. mallei. B. thailandensis is a weakly pathogenic species closely related to both B. pseudomallei and B. mallei. It is used as a study model. These bacteria are able to exhibit multiple resistance mechanisms towards various families of antibiotics. By sequentially plating B. thailandensis wild type strains on chloramphenicol we obtained several resistant variants. This chloramphenicol-induced resistance was associated with resistance against structurally unrelated antibiotics including quinolones and tetracyclines. We functionally and proteomically demonstrate that this multidrug resistance phenotype, identified in chloramphenicol-resistant variants, is associated with the overexpression of two different efflux pumps. These efflux pumps are able to expel antibiotics from several families, including chloramphenicol, quinolones, tetracyclines, trimethoprim and some β-lactams, and present a partial susceptibility to efflux pump inhibitors. It is thus possible that Burkholderia species can develop such adaptive resistance mechanisms in response to antibiotic pressure resulting in emergence of multidrug resistant strains. Antibiotics known to easily induce overexpression of these efflux pumps should be used with discernment in the treatment of Burkholderia infections.

International audience; OBJECTIVES: Francisella tularensis subsp. holarctica strains are classified as biovars I and II, which are susceptible and naturally resistant to the macrolide erythromycin, respectively. The present study was aimed at both selecting biovar I strains with increased levels of erythromycin resistance and characterizing the underlying genetic mechanisms. METHODS: Serial cultures in the presence of increasingly high erythromycin concentrations were performed to select independent high- and intermediate-level erythromycin-resistant mutants from each of three different biovar I strains. The mutants were characterized for cross-resistance to several antibiotics, presence of mutations in the genes encoding the 23S rRNA and the L4 and L22 ribosomal proteins, and overexpression of efflux pumps. RESULTS: Mutants displayed cross-resistance to all macrolide compounds tested but not to other classes of antibiotics. We found mutations in domain V of the 23S rRNA gene (G2057A, A2058G, A2058T and C2611T) and in the gene encoding L22, leading to either the G91D substitution or the M82K83R84 deletion. Analysis of mutants with intermediate resistance levels obtained over the course of the selection process revealed both a positive correlation between the number of mutated ribosomal operons and the resistance level, and an additional resistance mechanism in the early steps of selection. CONCLUSIONS: We showed that high-level resistance to macrolides can be easily obtained in vitro in F. tularensis subsp. holarctica biovar I strains, thereby suggesting that in vivo selection for resistance may explain reported failures of antibiotic treatment. Ketolides were the most effective macrolides tested, which may limit the risk of selection for resistance.

Objectives Fifty isolates of Burkholderia pseudomallei and 15 isolates of Burkholderia mallei were tested for their susceptibilities to 35 antimicrobial agents, including agents not previously tested against these bacteria. Methods MICs were determined by agar dilution in Mueller-Hinton medium. Results Among the antibiotics tested, lower MICs were obtained with imipenem, ceftazidime, piperacillin, piperacillin/tazobactam, doxycycline and minocycline. Fluoroquinolones and aminoglycosides had poor activities. A single clinical isolate of B. pseudomallei was resistant to ceftazidime, co-amoxiclav and doxycycline but remained susceptible to imipenem. Conclusions Although B. mallei MICs are often lower, the overall results underline the importance of resistance in both species. The susceptibilities measured are consistent with the current recommendations for the treatment of B. pseudomallei and B. mallei infections.