In vitro susceptibilities of suspected periodontopathic anaerobes as determined by membrane transfer assay

Abstract

Attempts to devise an antimicrobial approach to combating dentomicrobial infections such as periodontal diseases continue to be hampered by the lack of a relevant in vitro method for determining the susceptibility of suspected periodontopathogens to topically applied antimicrobial agents. Proposed here is a novel in vitro method called the membrane transfer technique, which acknowledges those aspects unique to localized pathogenic infections, particularly those associated with anaerobic bacteria. Bacterial lawns representing six suspected periodontopathic bacteria were prepared on membranes and then placed in contact with different concentrations of antimicrobial agents for 5 min. After incubation for 12 to 24 h, MBCs were determined with the aid of a tetrazolium chloride indicator. Four antimicrobial agents (chlorhexidine, iodine, stannous fluoride, and sodium fluoride) were used to test the applicability of the proposed in vitro method. MBCs were derived for each agent except sodium fluoride against all or most of the six bacterial strains tested. The proposed method may also be useful for examining the bactericidal action of topically applied antimicrobial agents against nonoral infections.

Molecular Characterization of Vancomycin-Resistant Enterococci Repopulating the Gastrointestinal Tract following Treatment with a Novel Glycolipodepsipeptide, Ramoplanin

“…The following agents were considered to have significant activities against anaerobic organisms: ␤-lactams and ␤-lactamase inhibitors, cefotetan, chloamphenicol, chlorhexidine (oral) (3,19,24), clindamycin, imipenem, metronidazole, rifampin (7,8), and trovafloxacin. Recent antibiotic use was defined as receipt of an antibacterial agent within the 2 weeks preceding enrollment into the study.…”

“…The organism's genotype was determined by PCR with primers specific for vanA, vanB, vanC1, and vanC2 (6, 22). The baseline isolate from each patient and the first isolate after the baseline isolate positive for vancomycin resistance were analyzed by pulsed-field gel electrophoresis by standard techniques, as reported previously (1, 9, 26).The following agents were considered to have significant activities against anaerobic organisms: ␤-lactams and ␤-lactamase inhibitors, cefotetan, chloamphenicol, chlorhexidine (oral) (3,19,24), clindamycin, imipenem, metronidazole, rifampin (7,8), and trovafloxacin. Recent antibiotic use was defined as receipt of an antibacterial agent within the 2 weeks preceding enrollment into the study.…”

Susceptibility testing of anaerobic bacteria: myth, magic, or method?

“…It has long been recognized that NCCLS reference methods are not appropriate for evaluating antimicrobial agents applied topically for ocular or dental infections. Caulfield et al (24) devised an assay that was designed to predict more closely the bactericidal effects of antimicrobial agents applied topically for short periods against dense aggregates of bacteria. They tested strains of periodontopathic organisms, including B. gingivalis, B. intermedius, and F. nucleatum.…”

Iodine release and antibacterial effects of a wound paste combined with PVP-iodine powder and/or solution in vitro

“…PVP-iodine could be a candidate as it represents an antiseptic with a broad antibacterial spectrum covering Grampositive and -negative bacteria and mycobacteria, [14] Staphylococcus spp., Candida albicans [15] and periopathogenic germs. [16,17]. A systematic review focussing on PVP-iodine as an adjunct to scaling and root planning proved evidence for an improved therapeutic effect regarding pocket depth reduction [18].…”