Aims: To investigate the survivability of vancomycin resistant enterococci (VRE) under dry starvation conditions and the fitness cost of vancomycin resistance. Methods: VRE colonies on cotton swabs were incubated at room temperature in a sterile box and cultured weekly until cultures no longer showed growth. Negative swabs inoculated into brain heart infusion (BHI) broth were subcultured to blood agar after 24, 48, and 72 hours of incubation to resuscitate viable but non-culturable cells. Stability of the vancomycin resistance determinant and of the DNA fingerprint pattern was determined by multiplex polymerase chain reaction (PCR) and repetitive PCR, respectively. Tests for fitness cost were carried out on the same VRE isolates and 28 hospital vancomycin sensitive enterococci (VSE) isolates by incubation and measurement of optical density using a microplate reader and comparing maximum growth rate and lag phase duration between VRE and VSE, using independent samples t tests. Results: Mean maximum time of recovery by primary culture was 8.5 weeks for Enterococcus faecalis VRE and 21.8 weeks for E faecium VRE. Two of two E faecalis isolates were resuscitated after 24 hours in BHI broth, and two of five E faecium isolates after 72 hours. No fitness cost of vancomycin resistance was demonstrated. Conclusions: VRE can survive for prolonged periods in a dry starvation state, retaining their genetic complement, including vancomycin resistance determinants, and show little or no fitness cost of vancomycin resistance. Thus, the rate of entry required for VRE to become, and remain, endemic in the community is relatively small.

Aims:To investigate biofilm production and esp carriage in enterococci.Methods:Biofilm production in vancomycin resistant enterococci (VRE) and vancomycin susceptible enterococci (VSE) was tested on a microtitre plate method, using both brain heart infusion (BHI) broth and human serum as media. Isolates were screened for the esp gene, which has been reported to be essential for biofilm formation in enterococci, by means of the polymerase chain reaction.Results:None of seven VRE and nine of 28 VSE tested formed a biofilm. One initially negative VREEnterococcus faeciumisolate produced a strong biofilm after 21 weeks of dry starvation on a cotton swab. By Fisher’s exact test, there was no significant difference in biofilm formation between VRE and VSE,E faecalisandE faecium, or isolates from different sites. Biofilm formation was independent of possession of the esp gene. One isolate produced a strong biofilm in human serum but only a weak biofilm in BHI, whereas another produced a moderate biofilm in human serum but a weak biofilm in BHI.Conclusions:The acquisition of vancomycin resistance may result in a lower ability to form biofilms, but a larger study using clinical isolates is needed to test this hypothesis. That one initially negative VRE isolate produced a strong biofilm after prolonged dry starvation suggests that biofilm formation may be an adaptive response. The esp gene does not appear to be necessary or sufficient for production of biofilms in enterococci.

Staphylococcus aureus is an infectious bacteria with pus because of tissue damage. Infectious diseases caused by S. aureus include wound infections, ulcers, pimples, and impetigo. Dayak onions have the benefit of being antibacterial. This research aims to study the antibacterial activity of ethanolic extract of Dayak onions against  Staphylococcus aureus. The antibacterial study was carried out using the disk diffusion method. Identification of bacteria by Gram staining showed Gram-positive bacteria which can ferment mannitol with the mannitol test. A bacterial sensitivity test was conducted using three antibiotics i.e. cefoxitin 30μg, vancomycin 30μg, and linezolid 30μg. The bacteria was sensitive to all of the three antibiotics, with the inhibitory zone of 23.5 mm; 17 mm and 27.5 mm, respectively. Vancomycin 30μg was used as a positive control, resulted in average diameter of the inhibitory zone of 17.83  2.25 mm, whereas a control solvent DMSO (Dimethyl sulphoxide) did not produce zones. The ethanolic extract of Dayak onion in the concentration of 25%; 50%; 75% and 100% showed the average diameter of inhibitory zones of 8.17  0.29  mm; 10.67  1.44 mm; 10.33  1.53 mm; and 12.33  1.61  mm, respectively