Antibiotic characteristics of clinical isolates of multi-drug resistant Stenotrophomonas maltophilia strains in the military hospital Vietnam

Stenotrophomonas maltophilia (S. maltophilia) is its best known species because it is a globally emerging, multidrug-resistant (MDR), opportunistic pathogen. The aim of the study was to identify species in this collection, defined as genetically cohesive sequence clusters, and to determine the extent of their genetic, ecological and phenotypic differentiation. This framework was used to analyze 50 specimens for cultures were collected from patients in the military hospital in Hanoi, Vietnam, between 2015 and 2017. Three of the 30 MDR S. maltophilia isolates identified by Vitek technology in hospital were confirmed using 16S rRNA gene sequencing. The alignment sequences were analyzed in RAxML version 8.2.10 to estimate the best maximum likelihood phylogenetic tree, with 1,000 bootstrap replicates, estimated GTRGAMMA model and the rapid bootstrapping algorithm. Over 70% of S. maltophilia isolates were resistant to β-lactams (such as carbapenem, penicilline, monobactam, amoxicillin, cephem, and β-lactam); Aminoglycosides (such as gentamycine and tobramycin); Miscellaneous (such as fosfomycin and chloramphenicol). In particularly, all of this strain isolates were resistant to β-lactams and Aminoglycosides high annual increasing/ frequency from 2015 to 2017 year. Three resistant strains with most antibiotics (S. maltophilia 17-87M, 17-95M and 17-90N) were randomly selected to test the association between genotype and phenotypic resistance. The results were shown a significantly different in antibiotic genes expression among three strains and a few difference in phenotypic resistance. These data in light of current models of bacterial speciation, which fit these data well, are stressing the implications of species delimitation in ecological, evolutionary and clinical research