ABSTRACTAchromobacterspp. are nonfermentative Gram-negative bacilli considered emergent pathogens in cystic fibrosis (CF). Although some cross-transmission events between CF patients have been described,Achromobacterstrains 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 byAchromobacter xylosoxidanswith the aim of evaluating the potential role of domestic reservoirs in sustaining airway colonization of the patients. Samples were screened for the presence ofAchromobacterby 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 ofAchromobacterspecies (n= 7), includingAchromobacter mucicolensandA. animicus, two species previously isolated from human samples only, and genotypes (n= 15), all showing an overall susceptibility to antimicrobial agents.Achromobacterstrains 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 majorAchromobacterspecies inhabiting domestic environments.A. xylosoxidansgenotypes 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 ofA. xylosoxidansclones adapted to the CF airways is probably impaired.IMPORTANCEAchromobacterspp. 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 ofAchromobacterspp. in CF patients' homes has not been explored. The domestic environments of CF patients chronically colonized byAchromobacter, especially wet environments, host several opportunistic pathogens, including a large diversity ofAchromobacterspecies and genotypes. However,Achromobactergenotypes 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.
Patterns of virulence factor expression and antimicrobial resistance in Achromobacter xylosoxidans and Achromobacter ruhlandii isolates from patients with cystic fibrosis
