Epidemiology and molecular characterization of in recovered from patients with bloodstream infections in Changsha, central China.

Objectives: The main aim of this study was to investigate the prevalence and molecular characteristics of the gene in isolates obtained from all patients with bloodstream infections over a year in a Chinese teaching hospital. We also assessed the susceptibility profiles of the -positive strains and prognostic impact of this gene on the patients.

Methods: A total of 144 consecutive, non-repetitive isolates causing bloodstream infections were collected at a teaching hospital in Changsha, China from January to December 2016. The presence of the gene was assessed by PCR. All -positive isolates were characterized by antimicrobial susceptibility testing, multilocus sequence typing (MLST), a conjugation experiment, and plasmid replicon typing. Clinical data were obtained from medical records.

Results: The gene was detected in three (2.1%) of the 144 isolates. The three -positive isolates were resistant to colistin. All three isolates showed a lower resistance to other classes of antibacterials, with all three being susceptible to carbapenems. The MLST results indicated that the three isolates were assigned to three different sequence types: ST457, ST101, and ST1413, respectively. The conjugation experiment showed that the gene was successfully transferred to the recipient ( EC600) from two isolates, one of which possessed IncI1 replicons and the other of which carried IncHI2 and IncN replicons. The patients with bloodstream infections caused by -positive isolates had severe underlying diseases and were cured after antibacterial treatment.

Conclusion: The prevalence of the gene in patients with bloodstream infection was 2.1% in Changsha, China. The -positive isolates had varied susceptibility profiles, although all three were susceptible to carbapenems. This therapeutic window is crucial given the risk of rapid deterioration in high-incidence areas worldwide.