Serratia marcescens SCH909 as reservoir and source of genetic elements related to wide dissemination of antimicrobial resistance mechanisms

GAMBINO A; DERASPE M; ALVAREZ VE; QUIROGA MP; CORBEIL JACQUES; ROY P; CENTRON DANIELA

FEMS MICROBIOLOGY LETTERS

WILEY-BLACKWELL PUBLISHING, INC

Año: 2023

0378-1097

Serratia marcescens SCH909 is a multidrug resistant strain isolated in 1988 28 harbouring three class 1 integrons. We wondered if these integrons were retained over 29 time and if there were other antimicrobial resistant determinants contributing to its 30 multidrug resistant profile. Genomic analysis showed a fourth multidrug resistance 31 integron, a Tn7 transposon with dfrA1-sat2-ybeA-ybfA-ybfB-ybgA gene cassettes in the 32 variable region. Insertion sequences were involved in the genesis of novel composite 33 transposons in the IncL4 plasmid pSCH909, such as Tn6824 carrying an arsenic regulon 34 and two head to head class 1 integrons surrounded by two complete IS1. Remarkably, a 35 novel chromosomal genomic island, SmaR, was identified, closely related to Multiple 36 Antimicrobial Resistance Regions (MARR), usually found in AbaR0-type and AbGRI2-37 0 from global clones of Acinetobacter baumannii, and in IncM-type plasmids 38 circulating in Enterobacteriaceae. Maintenance studies showed that the three class 1 39 integrons were maintained over one month without antimicrobial pressure. Since 40 Serratia marcescens is considered a relevant nosocomial pathogen that can have a wide 41 range of niches ? human, plant, animal, soil, and inanimate surfaces, our findings 42 support the ability of this species to capture, maintain and spread a broad variety of 43 antimicrobial resistance elements.