Distribution of the species of Achromobacter in a French Cystic Fibrosis Centre and multilocus sequence typing analysis reveal the predominance of A. xylosoxidans and clonal relationships between some clinical and environmental isolates.

Achromobacter spp. are emerging pathogens in Cystic Fibrosis (CF) patients. Recent studies proposed Multilocus Sequence Typing (MLST) scheme and a species-level identification method by nrdA sequencing for this genus. Epidemiological data are needed to assess the species and/or the sequence types (STs) involved and their potential role in CF patients lung function degradation. The aims of this study were i) to describe the distribution of the different species of Achromobacter in our CF centre ii) to detect potential STs more involved in chronic colonisations iii) to detect a potential local or worldwide predominance of some STs among clinical and environmental isolates. All the isolates (477) collected in our CF centre from 2007 to 2014 among the 177 patients attending the centre were identified using nrdA sequencing. MLST analysis was performed for 37 clinical and 14 environmental isolates. A total of 47 out of 177 patients presented positive culture(s) with Achromobacter spp., representing 12.7% of the patients of the centre each year. Eleven species were detected, A. xylosoxidans being the most prevalent species (27 patients). Only A. xylosoxidans (>80%) and A. insuavis were involved in chronic colonisation (6.7%). MLST analysis revealed a wide diversity among the isolates (36 STs for 51 isolates). Nevertheless, one third of the isolates belonged to STs previously detected in clinical isolates from other countries. This study is a first approach in understanding the global epidemiology of Achromobacter species in CF. These results confirm the high prevalence of the species A. xylosoxidans among CF patients, reveal the worldwide distribution of some STs and point out the potential role of environmental sources of contamination. More studies are needed to search for relationships between species and/or ST and pathogenicity.

Amoureux L ，Bador J ，Bounoua Zouak F ，Chapuis A ，de Curraize C ，Neuwirth C ... -  《-》

Use of nrdA gene sequence clustering to estimate the prevalence of different Achromobacter species among Cystic Fibrosis patients in the UK.

We aimed to estimate the prevalence of different Achromobacter species among UK Cystic Fibrosis (CF) patients. nrdA sequence clustering was used to identify 147 Achromobacter isolates from 96 patients from 27 hospitals to species level. Potential cross-infection was investigated by MLST, pulsed-field gel electrophoresis and whole genome sequencing (WGS). Achromobacter xylosoxidans was the most prevalent species affecting 59 of 96 (61%) patients, followed by Achromobacter insuavis and Achromobacter dolens (12.4% and 8%, respectively). Three novel nrdA clusters were identified. One was further characterised by sequencing the intrinsic blaOXA gene, revealing novel variants. WGS of A. insuavis 2a isolates from four patients attending the same paediatric unit revealed that three were ST144, but differed from one another by a minimum of 385 SNPs, suggesting cross-infection was unlikely. nrdA sequence clustering permitted an estimation of UK Achromobacter species prevalence, highlighted additional novel species, and aided cross-infection investigations.

Coward A ，Kenna DT ，Perry C ，Martin K ，Doumith M ，Turton JF ... -  《-》

Study of 109 Achromobacter spp. isolates from 9 French CF centres reveals the circulation of a multiresistant clone of A. xylosoxidans belonging to ST 137.

We previously reported the distribution of Achromobacter spp. (species and Sequence Types (ST)) in our French Cystic Fibrosis (CF) centre. In the present study we collected 109 Achromobacter isolates (1/patient) from 9 other French CF Centres for species identification, antimicrobial susceptibility testings and Multilocus-Sequence-Typing (MLST) analysis. Ten species were detected, A. xylosoxidans being the most predominant one (73.4% of the isolates). Piperacillin-tazobactam, ceftazidime, imipenem, meropenem and ciprofloxacin were respectively active against 88, 70, 79, 72 and 23% of the isolates. Among the 79 A. xylosoxidans isolates, 46 STs were detected. Interestingly, ST 137, recovered in 4 centres (5 patients), was previously detected in our centre (2 patients). The strains from the 7 patients belonged to the same pulsotype (pulsed-field-gel-electrophoresis analysis) and harboured acquired resistance to meropenem, ceftazidime, ciprofloxacin, and except for 2 isolates, to imipenem and piperacillin-tazobactam. This is the first description in France of a circulating multiresistant A. xylosoxidans strain.

Amoureux L ，Sauge J ，Sarret B ，Lhoumeau M ，Bajard A ，Tetu J ，Bador J ，Neuwirth C ，MucoMicrobes group ... -  《-》

Chronic Airway Colonization by Achromobacter xylosoxidans in Cystic Fibrosis Patients Is Not Sustained by Their Domestic Environment.

Achromobacter spp. are nonfermentative Gram-negative bacilli considered emergent pathogens in cystic fibrosis (CF). Although some cross-transmission events between CF patients have been described, Achromobacter strains were mostly patient specific, suggesting sporadic acquisitions from nonhuman reservoirs. However, sources of these emergent CF pathogens remain unknown. A large collection of specimens (n = 273) was sampled in the homes of 3 CF patients chronically colonized by Achromobacter xylosoxidans with the aim of evaluating the potential role of domestic reservoirs in sustaining airway colonization of the patients. Samples were screened for the presence of Achromobacter by using genus-specific molecular detection. Species identification, multilocus genotypes, and antimicrobial susceptibility patterns observed for environmental isolates were compared with those of clinical strains. Patient homes hosted a high diversity of Achromobacter species (n = 7), including Achromobacter mucicolens and A. animicus, two species previously isolated from human samples only, and genotypes (n = 15), all showing an overall susceptibility to antimicrobial agents. Achromobacter strains were mostly isolated from indoor moist environments and siphons, which are potential reservoirs for several CF emerging pathogens. A. xylosoxidans, the worldwide prevalent species colonizing CF patients, was not the major Achromobacter species inhabiting domestic environments. A. xylosoxidans genotypes chronically colonizing the patients were not detected in their household environments. These results support the notions that the domestic environment could not be incriminated in sustained patient colonization and that after initial colonization, the environmental survival of A. xylosoxidans clones adapted to the CF airways is probably impaired.IMPORTANCEAchromobacter spp. are worldwide emerging opportunistic pathogens in CF patients, able to chronically colonize the respiratory tract. Apart from regular consultations at the hospital CF center, patients spend most of their time at home. Colonization from nonhuman sources has been suggested, but the presence of Achromobacter spp. in CF patients' homes has not been explored. The domestic environments of CF patients chronically colonized by Achromobacter, especially wet environments, host several opportunistic pathogens, including a large diversity of Achromobacter species and genotypes. However, Achromobacter genotypes colonizing the patients were not detected in their domestic environments, making it unlikely that a shuttle between environment and CF airways is involved in persisting colonization. This also suggests that once the bacteria have adapted to the respiratory tract, their survival in the domestic environment is presumably impaired. Nevertheless, measures for reducing domestic patient exposure should be targeted on evacuation drains, which are frequently contaminated by CF opportunistic pathogens.

Dupont C ，Jumas-Bilak E ，Doisy C ，Aujoulat F ，Chiron R ，Marchandin H ... -  《-》

Epidemic Achromobacter xylosoxidans strain among Belgian cystic fibrosis patients and review of literature.

Cools P ，Ho E ，Vranckx K ，Schelstraete P ，Wurth B ，Franckx H ，Ieven G ，Van Simaey L ，Van Daele S ，Verhulst S ，De Baets F ，Vaneechoutte M ... -  《BMC MICROBIOLOGY》