Sun Ziyong

Efficacy of Atmospheric Pressure Plasma as an Antibacterial Agent Against Enterococcus Faecalis in Vitro

Enterococcus faecalis (E. faecalis) is a microorganism that can survive extreme challenges in obturated root canals. The aim of this study was to evaluate the efficacy of a non-thermal atmospheric pressure plasma plume against E. faecalis in vitro. A non-thermal atmospheric pressure plasma jet device which could generate a cold plasma plume carrying a peak current of 300 mA was used. The antibacterial efficacy of this device against E. faecalis and its biofilm under different conditions was detected. The antibacterial efficacy of the plasma against E. faecalis and Staphylococcus aureus (S. aureus) was also evaluated. After plasma treatment, the average diameter of inhibition zone on S. aureus and E. faecalis was 2.62±0.26 cm and 1.06±0.30 cm, respectively (P < 0.05). The diameter was increased with prolongation of the treatment duration. The diameters of inhibition zone of the sealed Petri dishes were larger than those of the uncovered Petri dishes. There was significant difference in colony-forming units between plasma group and control group on E. faecalis biofilm (P < 0.01). The transmission electron microscopy revealed that the ultrastructural changes cytoderm of E. faecalis were observed after treatment for 2 min. It is concluded that the non-thermal atmospheric pressure plasma could serve as an effective adjunct to standard endodontic microbial treatment.

Analysis of etiology and drug resistance of biliary infections.

SummaryThe bile was collected from fro patients with biliary infections, with the bacterium isolated to study the sensitivity of each kind of the bacterium to several antibiotics in common use. Except G bacterium, we also found some kinds of G− bacterium in infection bile, G− bacterium were not sensitive to Clindamycin. G− bacterium were sensitive to Ciprofloxacin. Escherichia coli. Xanthomonas maltophilia. Enterobacter cloacae. Pseudomonas aeruginosa were sensitive to Ampicillin, G− bacterium were not sensitive to Azactam. Enterococcus faccalis. Enterococcus faecium. Enterobacter cloacae were not sensitive to Ceftazidime. Enterococcus faccalis. Staphylococcus coagulase negative. Staphylococcus epidermidis. Pseudomonas aeruginosa were not sensitive to Ceftriaxone Sodium. We didn’t found any bacterium resistance Imipenem. The possibility of the existence of G− bacterium as well as drug resistance should be considered n patients with biliary infections. The value of susceptibility test should be respected to avoid drug abuse of antibiotics.

Analysis on antimicrobial resistance of clinical bacteria isolated from county hospitals and a teaching hospital

SummaryThe distinction of antimicrobial resistance of clinical bacteria isolated from county hospitals and a teaching hospital was investigated. Disc diffusion test was used to study the antimicrobial resistance of isolates collected from county hospitals and a teaching hospital. The, data was analyzed by WHONET5 and SPSS statistic software. A total of 655 strains and 1682 strains were collected from county hospitals and a teaching hospital, respectively, in the year of 2003. The top ten pathogens were Coagulase negative staphylococci (CNS), E. coli, Klebsiella spp., S. areus, P. aeruginosa, Enterococcus spp., Enterobacter spp., otherwise Salmonella spp., Proteus spp., Shigella spp. in county hospitals and Streptococcus spp., Acinetobacter spp., X. maltophilia in the teaching hospital. The prevalence of multi-drug resistant bacteria was 5% (4/86) of methicillin-resistant S. areus (MRSA), 12% (16/133) and 15.8% (9/57) of extended-spectrum β-lactamases producing strains of E. coli and Klebsiella spp., respectively, in county hospitals. All of the three rates were lower than that in the teaching hospital and the difference was statistically significant (P<0.01). However, the incidence of methicillin-resistant CNS (MRCNS) reached to 70% (109/156) in the two classes of hospitals. Generally, the antimicrobial resistant rates in the county hospitals were lower than those in the teaching hospital, except the resistant rates of ciprofloxacin, erythromycin, clindamycin, SMZco which were similar in the two classes of hospitals. There were differences between county hospitals and the teaching hospital in the distribution of clinical isolates and prevalence of antimicrobial resistance. It was the basis of rational use of antimicrobial agents to monitor antimicrobial resistance by each hospital.