Acinetobacter species isolates from a range of environments: species survey and observations of antimicrobial resistance

Abstract

Acinetobacter species isolates from a range of environments, including soil, were investigated. We determined 16S rRNA and rpoB gene sequences for species identification and performed tests of antimicrobial resistance susceptibility. Twenty-nine of the isolates (8 from soil and 21 from life environment) belonged to the genus Acinetobacter. Fourteen Acinetobacter species were identified among 29 isolates: 4 A. baumannii, 3 A. calcoaceticus, 1 A. nosocomialis, 2 A. pittii, and 2 Acinetobacter gen. sp. 'close to 13TU' as A. calcoaceticus-baumannii complex. Three Acinetobacter species isolates were identified as novel species candidates. Three Acinetobacter species isolates were resistant to imipenem: 1 A. parvus and 2 novel species candidates of Acinetobacter. Eight isolates showed resistance to colistin: all Acinetobacter gen. sp. 'close to 13TU' (2 isolates) and A. parvus isolates (3 isolates) were resistant to colistin. Although the genotypes of A. baumannii isolates from various natural environments were different from those of clinical isolates, the presence of clinically important and antimicrobial resistant Acinetobacter species in the natural environment may represent a threat to public health.