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.