The relative gene transfer was calculated
by dividing the % value of each treatment by the % value for the standard. Here transconjugants serve as a standard. Data were analyzed using Graph Pad InStat-3 and expressed as mean ± standard deviation (SD) of three independent experiment. The continuous variables were tested with one-way analysis of variance (ANOVA) and Dunnett’s test. Values <0.05 were considered statistically significant. Re-identification of all of the clinical isolates were done and found to be of VRSA. Among the clinical isolates, only 8 clinical isolates (1 surgical wounds, 2 bacteremia and 5 burns) were found to be positive for vanA ( Fig. 1) and one of the vanA positive isolates (from burns sample) used as a donor for conjugation study. Transconjugants were selected by using 16 μg/ml of vancomycin and 2.5 μg/ml ciprofloxacin because these were able to grow PF-06463922 mouse in the presence of both of the drugs. Further analysis of transconjugants through PCR confirmed that transconjugants carrying the same gene as donor suggesting that gene transfer had taken place from donor to recipient ( Fig. 2A and B). Conjugative transfer of resistant gene has been demonstrated in-vitro, 13, 14 and 19 suggesting that genetic
exchange of resistance http://www.selleckchem.com/products/ink128.html may occur naturally. Moreover, results of conjugation study revealed that when conjugative system was provided with disodium edetate caused a concentration dependent inhibition of conjugation. Treatment with disodium edetate showed a significant conjugation inhibition which started from 4.0 mM (77.5 ± 4.9; p > 0.05) and continued up to 10 mM of disodium edetate ( Fig. 3 & Table 1). The author hypothesized that 10 mM disodium edetate in combination of antibiotic can be a novel approach to control and spreading of antibiotic resistance. Our lab has already established that disodium edetate to be safe upto 40 mg/kg/body weight when administered intravenously to Swiss albino
mice (communicated for publication). Additionally, Casein kinase 1 disodium edetate has been using intravenously in combination with vitamins and minerals in the treatment of various diseases including atherosclerotic vascular disease and renal ischemia. 20 and 21 Similarly, when conjugation was studied with various concentration of EGTA and boric acid, EGTA was found to inhibit conjugal transfer for vanA gene from donor to recipient at very high concentration that is 120 mM whereas boric acid failed to produces conjugation inhibition upto 150 mM (data not shown). The inhibition of conjugation by disodium edetate could be due to the inhibition of relaxases enzyme. DNA conjugative relaxases and rolling-circle replicating (RCR) initiator proteins, have been known to participate in the binding and coordination of the metal cation (Mg2+ or Mn2+) needed for cleavage of the DNA substrate.