Isolation and Characterization of a Phage to Control Vancomycin Resistant Enterococcus faecium

Abstract

Enterococcus faecium, is an important nosocomial pathogen with increased incidence of multidrug resistance (MDR) – specifically Vancomycin resistance. E. faecium constitutes the normal microbiota of the human intestine as well as exists in the hospitals and sewage, thus making the microorganism difficult to eliminate. Phage therapy has gained attention for controlling bacterial MDR infections and contaminations. We have successfully isolated from waste water and characterized a lytic bacteriophage STH1 capable of targeting Vancomycin resistant Enterococcus faecium (VREF) with high specificity. The phage was isolated from sewage water of a hospital at district Dera Ismail Khan, Pakistan. Initial characterization showed that magnesium and calcium ions significantly increased phage adsorption to the host. One step growth experiment showed a latent period of 18 min with burst size of 334 virions per cell. Optimal temperature and pH of the phage was 37°C and 7.0, respectively. Phage application to host strain grown in milk and water (treated and untreated) showed that the phage efficiently controlled bacterial growth. The study suggests that the phage STH1 can serve as potential control agent for E. faecium infections in medical facilities and in other environmental contaminations.

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

“…The optimum temperature for the biological activity of phage S2 was 37°C; however, the plaque formation decreased with increasing temperature from 37°C to 55°C but phage S2 exhibited acceptable stability in this temperature range. These findings are in agreement with previous studies (24,34). In this study, phage stability was investigated in a wide range of pH values (from 1 to 11).…”

“…According to the results, phage S2 required 10 mM Mg 2+ for maximum infectivity, while the presence of Ca 2+ had no significant effect on phage uptake. Similar to our report, Taskeen Raza et al (2018) reported that Mg 2+ significantly increased phage uptake into the host cell and improved plaque formation (24). In contrast to our study, Sidra Rahmat Ullah et al reported that the addition of Ca 2+ affected phage SRG1 absorption (34).…”

“…In this investigation, 34 vanA positive E. faecium isolates were recovered from clinical samples. We isolated four specific lytic phages for VREfm host strains from hospital sewage comparable with our experiment, Vancomycin-resistant E. faecium-specific phages have been isolated in other studies (19,20,24). One phage was selected for further evaluations based on a broader host spectrum and larger plaque size.…”

“…A one-step growth experiment was conducted as described previously (24). Briefly, 50 ml of mid-exponential phase (OD600=0.4-0.6) VREfm2 was precipitated by centrifugation (14000 rpm, 5 min).…”

Antibiogram Pattern and Virulence Trait Characterization of Enterococcus Species Clinical Isolates in Eastern India: A Recent Analysis

“…12 13 14 15 Of nine types of vancomycin-related operons/genetic elements ( vanA , vanB , van C1/C2/C3 , vanD , vanE , vanG , vanL , vanM , and vanN ), associated with glycopeptide-resistance in enterococci, van A , and van B are by far the most prevalent types and E. faecium is the predominant species of GRE. 8 9 10 11…”