55 Is whole genome sequencing necessary to exclude cross infection with Mycobacterium abscessus ST26 in paediatric cystic fibrosis patients?

Abstract

Objective Patients with Cystic Fibrosis (CF) can be colonized or infected with M. abscessus. Our centre along with others in the UK has seen an increase in patients with this organism. We have reviewed M. abcessus cases since 2011 to attempt to ascertain whether there is a genuine increase in the incidence of this infection and whether there is any possibility of cross infection within our patient group. Methods Retrospective data on paediatric M. abscessus isolates were retrieved from the microbiology laboratory computer system and historical CF databases. Isolates of M. abscessus were sent to PHE, Colindale, for genetic analysis. Results There has been a genuine increase in M. abscessus colonization amongst our paediatric CF population over time. Sampling patterns have varied but isolation rates were independent of numbers of sputum samples and patients tested. Five of 13 paediatric patients colonized with M. abscessus harboured strains belonging to clonal lineage ST26. Of these 5, no patients had any recorded opportunity for direct contact within the hospital and we could find no epidemiological evidence of any periods when cross infection could have occurred. Remaining patient isolates were distinct. The isolates from the ST26 patients were sequenced and whole genome analysis was performed. Conclusion The control of cross infection is an important aspect of CF care. Since diverse ST26 strains have been reported in the context of CF, further genetic analysis including whole genome sequencing may be required to determine any relatedness between isolates and exclude the possibility of hospital acquired M. abscessus infection.