Effectiveness of ozone against periodontal pathogenic microorganisms.

Ozone has been proposed as an adjunct antiseptic in periodontitis therapy. The aim of this study was to investigate the antimicrobial effectiveness of gaseous/aqueous ozone, in comparison with that of the established antiseptic chlorhexidine digluconate (CHX), against periodontal microorganisms. Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, and Parvimonas micra in planktonic or biofilm cultures were exposed, for 1 min, to gaseous ozone, aqueous ozone, CHX, or phosphate-buffered saline (control). None of the agents was able to substantially reduce the A. actinomycetemcomitans count in biofilm cultures. In contrast, P. gingivalis, T. forsythia, and P. micra could be eliminated by 2% CHX or by ozone gas at 53 gm(-3) . Significantly greater antimicrobial effects were observed against planktonic cultures than against biofilm-associated bacteria. The rate of killing was influenced by the species of bacteria, and by the type and concentration of agent. There were no significant differences in the effectiveness of aqueous ozone (20 µg ml(-1) ) or gaseous ozone (≥ 4 gm(-3) ) compared with 2% CHX but they were more effective than 0.2% CHX. Therefore, high-concentrated gaseous and aqueous ozone merit further investigation as antiseptics in periodontitis therapy. A safe system for applying gaseous ozone into the periodontal pocket that avoids inhalation still needs to be developed.

In vitro activity of moxifloxacin and piperacillin/sulbactam against pathogens of acute cholangitis.

AIM: To analyze the in vitro activity of moxifloxacin and piperacillin/sulbactam against pathogens isolated from patients with acute cholangitis. METHODS: In this prospective study a total of 65 patients with acute cholangitis due to biliary stone obstruction (n = 7), benign biliary stricture (n = 16), and malignant biliary stricture (n = 42) were investigated with regard to spectrum of bacterial infection and antibiotic resistance. Pathogens were isolated from bile cultures in all study patients. In 22 febrile patients, blood cultures were also obtained. In vitro activity of moxifloxacin and piperacillin/sulbactam was determined by agar diffusion. RESULTS: Thirty-one out of 65 patients had positive bile and/or blood cultures. In 31 patients, 63 isolates with 17 different species were identified. The predominant strains were Enterococcus species (26/63), E.coli (13/63) and Klebsiella species (8/63). A comparable in vitro activity of moxifloxacin and piperacillin/sulbactam was observed for E.coli and Klebsiella species. In contrast, Enterococcus species had higher resistances towards moxifloxacin. Overall bacteria showed antibiotic resistances in vitro of 34.9% for piperacillin/sulbactam and 36.5% for moxifloxacin. CONCLUSION: Enterococcus species, E.coli and Klebsiella species were the most common bacteria isolated from bile and/or blood from patients with acute cholangitis. Overall, a mixed infection with several species was observed, and bacteria showed a comparable in vitro activity for piperacillin/sulbactam and moxifloxacin.

Sensitivity of the BacT/ALERT FA-medium for detection of Pseudomonas aeruginosa in pre-incubated blood cultures and its temperature-dependence.

The BacT/ALERT FA-medium was evaluated to detect Pseudomonas aeruginosa in pre-incubated blood samples. As published previously its predecessor the BacT/ALERT FAN-medium failed to detect P. aeruginosa in delayed entry samples. It is now reported that FA-medium tolerates a longer pre-incubation period at 36 degrees C, i.e. 8 h, before detection of P. aeruginosa fails in experimentally inoculated blood cultures. In clinical blood samples the frequency of false-negative results concerning P. aeruginosa was reduced from 46.9 % (FAN-medium) to 9.1 % (FA-medium). If media inoculated with P. aeruginosa are pre-incubated at room temperature for 24 h, false-negative results are not observed. Various micro-organisms (Haemophilus influenzae, Streptococcus pneumoniae, Enterobacteriaceae, Staphylococcus aureus, Enterococcus faecalis, Candida glabrata) were recognized after pre-incubation at room temperature with similar sensitivity compared to pre-incubation at 36 degrees C. It is concluded that FA-medium detects P. aeruginosa in delayed entry samples with increased sensitivity and pre-incubation at room temperature is superior to pre-incubation at 36 degrees C.