UNDERSTANDING OF THE STRATEGIES DEVELOPED BY ESCHERICHIA COLI TO ADAPT AND PERSIST IN THE AIRWAYS OF A PATIENT WITH CYSTIC FIBROSIS

VITA, CAROLINA; DALESSANDRO, VIRGINIA; OSVALDO YANTORNO; LEGUIZAMÓN, MARIANA; BELTINA LEÓN; RENTERIA FERNANDO; CASCO, DANIELA; BETTIOL, MARISA; ALEJANDRA BOSCH

ON LINE Event

Congreso; 34th annual North American Cystic Fibrosis Conference (NACFC) ON-LINE; 2020

North American Cystic Fibrosis Fundation

ObjectivesAlthough Escherichia coli has not been considered as a cystic fibrosis (CF) pathogen, it was recently reported that E. coli isolates can be persistent colonizers of CF lungs adapting by undergoing phenotypic changes similar to the traditional CF pathogens (Barillova P, et al. Int. J. Med. Microbiol. 2014; 304:415?421). The aim of this work is to advance in the knowledge of the phenotypic and genomic adaptation that lead E. coli to persist in the airways of a patient with CF.MethodsWe performed a comprehensive genomic and phenotypic analysis of 12 clinical isolates recovered from respiratory tract samples from a patient with CF attended at the Hospital de Niños de La Plata ?Sor María Ludovica? during a period of 4 years. The isolates were sequenced using an Illumina MiSeq platform. Genomic content was analyzed and single nucleotide polymorphisms (SNPs) were identified. Diverse phenotypic characteristics of the isolates were analyzed, such as colony morphology, biofilm formation capacity, bacterial motility (swarming, swimming and twitching), production of curli and cellulose in Congo-red agar plates, and various virulence factors. In addition, antimicrobial susceptibility against the antibiotics applied in clinical treatments were determined.ResultsMolecular typing demonstrated that the patient has been persistently colonized by a single E. coli strain, O25b:H4-ST131. This clone belongs to a widespread pandemic clonal group that has recently emerged worldwide producing antimicrobial-resistant urinary tract infections (Rogers BA, et al. J. Antimicrob. Chemother. 2011; 66(1):1?14). After 3 years of chronicity, in addition to the mucoid variant, a small colony variant (SCV) was recovered. The implication of SCV in chronic infections has been previously described for another microorganisms (Kahl B, et al. J Infect Dis. 1998;177(4):1023-1029; von Götz, F, et al. J Bacteriol. 2004;186(12):3837-3847). These SCV isolates showed a very slow growth rate and resistance to a greater number of antimicrobials. Congo red staining showed a continuous pattern of change suggesting that alteration in extracellular matrix composition might be one of the long-term adaptation strategies. The analysis of the long-term mutation accumulation showed that isolates have a low genome-wide mutation rate with the acquirer of genes related to membrane transport and regulation.ConclusionsTogether our study represents the first investigation that describes various phenotypic and genomic strategies that E. coli adopts to persist in chronic lung infection in a patient with CF.