Biological characteristics and anti-biofilm activity of a lytic phage against Enterococcus faecium

BACKGROUND AND OBJECTIVES Enterococcus faecium is emerging as one of the most common causes of nosocomial infections and due to its resistance to antimicrobial agents this organism is one of the major public health concerns. Bacteriophages are being considered as an alternative therapy to treat infections caused by multidrug-resistant bacteria. The purpose of this study was to isolate and characterize an effective antibiofilm bacteriophage against E. faecium isolated from hospitalized patients.MATERIALS AND METHODSThe bacteriophage was obtained from the sewage of hospital and its lytic activity was determined using the spot test and double-layer plaque assay. Transmission electron microscopy (TEM) was employed to determine the phage characterization. Furthermore, host range, optimal multiplicity of infection (MOI) and stability tests on different temperature and pH were conducted. The effect of the bacteriophage on ۱-۳-۵-day old preformed E. faecium biofilm was assessed using TTC assay.RESULTS AND DISCUSSION According to Electron microscopy observations, the isolated phage belonged to the Myoviridae family. Spot testing on the collected isolates indicated that bacteriophage was able to lyse ۲۰ out of ۳۶ isolates (۵۵%). Suitable pH spectra for phage survival was ۵–۱۱, at which the phage showed ۱۰۰% activity. The optimal temperature for phage growth was ۳۰– ۴۵°C, with the highest growth at ۳۷°C. The optimal MOI for isolated phage was ۰,۰۱.The phage at ۵.۶ × ۱۰۱۶ pfu/ml, ۲.۸ × ۱۰۱۶ pfu/ml and ۱.۴ × ۱۰۱۶ pfu/ml disrupted one, three and five day old biofilm of E. faecium isolates.CONCLUSION The high broad host range of the isolated phages is promising to control E. faecium infections and can be in the future commercially suitable for treatment as lysate preparations. Animal models of phage-bacterial interaction will be our next step that may help in resolving the multidrug resistant crisis of infections due to the E. faecium biofilm.

کلیدواژه ها:

Bacteriophage ، Enterococcus faecium ، Phage therapy