In vitro antimicrobial susceptibility of oral strains of Actinobacillus actinomycetemcomitans to seven antibiotics

Toxin-triggered liposomes for the controlled release of antibiotics to treat infections associated with the gram-negative bacterium, Aggregatibacter actinomycetemcomitans

Antibiotic resistance has become an urgent threat to health care in recent years. The use of drug delivery systems provides advantages over conventional administration of antibiotics and can slow the development of antibiotic resistance. In the current study, we developed a toxin-triggered liposomal antibiotic delivery system, in which the drug release is enabled by the leukotoxin (LtxA) produced by the Gram-negative pathogen, Aggregatibacter actinomycetemcomitans. LtxA has previously been shown to mediate membrane disruption by promoting a lipid phase change in nonlamellar lipids, such as 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-methyl (N-methyl-DOPE). In addition, LtxA has been observed to bind strongly and nearly irreversibly to membranes containing large amounts of cholesterol. Here, we designed a liposomal delivery system composed of N-methyl-DOPE and cholesterol to take advantage of these interactions. Specifically, we hypothesized that liposomes composed of N-methyl-DOPE and cholesterol, encapsulating antibiotics, would be sensitive to LtxA, enabling controlled antibiotic release. We observed that liposomes composed of N-methyl-DOPE were sensitive to the presence of low concentrations of LtxA, and cholesterol increased the extent and kinetics of content release. The liposomes were stable under various storage conditions for at least 7 days. Finally, we showed that antibiotic release occurs selectively in the presence of an LtxA-producing strain of A. actinomycetemcomitans but not in the presence of a non-LtxA-expressing strain. Together, these results demonstrate that the designed liposomal vehicle enables toxin-triggered delivery of antibiotics to LtxA-producing strains of A. actinomycetemcomitans.

Toxin-Triggered Liposomes for the Controlled Release of Antibiotics to Treat Infections Associated with Gram-Negative Bacteria

Antibiotic resistance has become an urgent threat to health care in recent years. The use of drug delivery systems provides advantages over conventional administration of antibiotics and can slow the development of antibiotic resistance. In the current study, we developed a toxin-triggered liposomal antibiotic delivery system, in which the drug release is enabled by the leukotoxin (LtxA) produced by the Gram-negative pathogen, Aggregatibacter actinomycetemcomitans. LtxA has previously been shown to mediate membrane disruption by promoting a lipid phase change in nonlamellar lipids, such as 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-methyl (N-methyl-DOPE). In addition, LtxA has been observed to bind strongly and nearly irreversibly to membranes containing large amounts of cholesterol. Here, we designed a liposomal delivery system composed of N-methyl-DOPE and cholesterol to take advantage of these interactions. Specifically, we hypothesized that liposomes composed of N-methyl-DOPE and cholesterol, encapsulating antibiotics, would be sensitive to LtxA, enabling controlled antibiotic release. We observed that liposomes composed of N-methyl-DOPE were sensitive to the presence of low concentrations of LtxA, and cholesterol increased the extent and kinetics of content release. The liposomes were stable under various storage conditions for at least 7 days. Finally, we showed that antibiotic release occurs selectively in the presence of an LtxA-producing strain of A. actinomycetemcomitans but not in the presence of a non-LtxA-expressing strain. Together, these results demonstrate that the designed liposomal vehicle enables toxin-triggered delivery of antibiotics to LtxA-producing strains of A. actinomycetemcomitans.

Periodontal microbiology and microbial etiology of periodontal diseases: Historical concepts and contemporary perspectives

This narrative review summarizes the collective knowledge on periodontal microbiology, through a historical timeline that highlights the European contribution in the global field. The etiological concepts on periodontal disease culminate to the ecological plaque hypothesis and its dysbiosis-centered interpretation. Reference is made to anerobic microbiology and to the discovery of select periodontal pathogens and their virulence factors, as well as to biofilms. The evolution of contemporary molecular methods and high-throughput platforms is highlighted in appreciating the breadth and depth of the periodontal microbiome. Finally clinical microbiology is brought into perspective with the contribution of different microbial species in periodontal diagnosis, the combination of microbial and host biomarkers for this purpose, and the use of antimicrobials in the treatment of the disease.

Discrepancies in Antimicrobial Susceptibility between the JP2 and the Non-JP2 Genotype of Aggregatibacter actinomycetemcomitans

The Aggregatibacter actinomycetemcomitans JP2 genotype is associated with high leukotoxin production and severe (aggressive) periodontitis. The aim of this study was to compare the antimicrobial susceptibility of JP2 and non-JP2 genotype strains. Minimal inhibitory concentrations (MICs) of 11 antimicrobials were determined for 160 A. actinomycetemcomitans of serotype a, b, or c, mostly isolated in Sweden or Ghana. MIC distributions for benzylpenicillin and fusidic acid revealed a more susceptible subpopulation for 38 serotype b strains, including the 32 of the JP2 genotype, with a benzylpenicillin MIC range of 0.125−0.5 mg/L. In contrast, benzylpenicillin MIC ≤ 16 mg/L was the estimated 99.5% epidemiological cutoff (ECOFF) of all strains. Beta-lactamase production was not detected. The fusidic acid MIC distribution of 11 strains of Aggregatibacter aphrophilus agreed with that found in non-JP2 strains. Cefotaxime, meropenem, levofloxacin, and trimethoprim−sulfamethoxazole MICs were all ≤0.25 mg/L, while MIC90 values for amoxicillin, azithromycin and tetracycline were 1 mg/L. Metronidazole MICs varied between 0.5 and >256 mg/L. The discrepant findings indicate that A. actinomycetemcomitans may be divided into two separate wild types, with a suggested intrinsic reduced susceptibility for benzylpenicillin in the majority of non-JP2 genotype strains. Possible implications for the treatment of A. actinomycetemcomitans infections are discussed.

In Vitro Antibacterial Activity of Myrtus communis L. and Marrubium vulgare L. Leaves against Aggregatibacter actinomycetemcomitans and Eikenella corrodens

Materials and Methods

Clinical strains of Aggregatibacter actinomycetemcomitans and Eikenella corrodens and two reference strains of A. actinomycetemcomitans were tested. The antibacterial activity of each studied plant extract was evaluated using agar diffusion and broth microdilution assays.

Results

Both aqueous and methanolic extracts of M. communis exhibited high antibacterial activity against periodontal pathogens as compared to M. vulgare extracts. At concentrations of 2.5-0.32 mg/disc, inhibition zones of the methanolic extract of M. communis ranged from 19.66 ± 0.57 to 12.33 ± 0.57 mm. The methanolic extract of M. vulgare showed at concentrations of 5-0.63 mg/disc inhibition zones ranging from 15.66 ± 0.57 to 12 ± 0.00 mm. Its aqueous extract at concentration of 0.63 mg/disc showed no antimicrobial activity against the clinical and reference strain of A. actinomycetemcomitans. Conclusion. This study showed that methanolic and aqueous extracts of M. communis and M. vulgare have in vitro an antibacterial activity against periodontal pathogens. They could be use as ingredients of an oral antimicrobial agent for prevention or treatment of periodontal diseases. Further research on isolating the compounds from these plant extracts and their toxicity effect could be conducted.

Antimicrobial susceptibility pattern of oral gram negative anaerobes from Indian subjects

OBJECTIVES

There is paucity of information on the antimicrobial susceptibility pattern of oral anaerobic bacteria. In this study, an attempt has been made to evaluate the antimicrobial susceptibility/resistance trend of oral Gram negative bacteria from Indian subjects.

METHODS

Minimum inhibitory concentrations (MIC) of 304 isolates against twelve different antibiotics were determined using gradient diffusion MIC strips. The organisms were isolated and identified based on phenotypic characteristics and included Porphyromonas gingivalis, Prevotella species, Tannerella forsythia, Fusobacterium nucleatum, Aggregatibacter actinomycetemcoitans, Eickenella corrodens and Capnocytophaga species. For each antimicrobial agent, MIC₅₀ and MIC₉₀ were calculated and expressed.

RESULTS

Resistance to azithromycin, clindamycin, and amoxicillin was observed in most of the anaerobic bacterial species studied. High degree of susceptibility was observed to amoxillin-clavulanic acid, doxycycline and moxifloxacin. A single strain of P. melaninogenica was resistant to moxifloxacin. The susceptibility pattern varied with cephalosporins among species. Ceftriaxone showed highest and cefazolin least efficacy among cephalosporins. All anaerobic bacteria tested were susceptible to metronidazole. Strains of T. forsythia were more resistant to several antibiotics than other anaerobic bacteria. All three species of capnophilic bacteria displayed high degree of resistance to metronidazole and significant resistance to amoxicillin, azithromycin, clindamycin, cefazolin and cefuroxime.

CONCLUSIONS

Amoxicillin-clavulanic acid, doxycycline, moxifloxacin and metronidazole appeared to be the most effective drugs against gram negative anaerobic bacteria. However, the MIC₅₀ and MIC₉₀ values against metronidazole were on the higher side of the normal indicating a potential for developing resistance.

Antimicrobial susceptibility pattern of oral isolates of Aggregatibacter actinomycetemcomitans

Background:

Aggregatibacter actinomycetemcomitans is involved in the etiology of localized aggressive periodontitis (LAP), a condition that frequently requires supplemental antibiotic therapy. Information on antimicrobial susceptibility pattern and guidelines for oral antibiotic therapy are not available on Indian patients.

Aim:

The main aim of the present study was to screen clinical isolates on a panel of antibiotics commonly used for oral/systemic therapy.

Materials and Methods:

The study included 40 strains of A. actinomycetemcomitans isolated from patients with LAP. The subgingival plaque was plated onto Trypticase Soy Serum Bacitracin Vancomycin Agar medium and incubated for 72 h, and suspected colonies were confirmed by phenotypic tests. Each isolate was tested against a panel of 12 antibiotics using MIC gradient strip test. ATCC strains of A. actinomycetemcomitans serotype A and C were used as standards. Performance and interpretation of the test were done according to the manufacturers’ instructions. Distribution of MICs among isolates (n = 40) were used to calculate concentrations inhibiting 50% (MIC₅₀) and 90% (MIC₉₀) of strains.

Results:

Moxifloxacin, cefotaxime and ceftriaxone showed excellent activity with 100% growth inhibition followed by amoxicillin, amoxiclav and doxycycline (>90% activity). The bacterial strains were moderately susceptible to cefuroxime, cefazolin and tetracycline but displayed poor susceptibility to clindamycin and azithromycin. All isolates were resistant to metronidazole.

Conclusion:

The isolates of A. actinomycetemcomitans displayed a high level of resistance to azithromycin and clindamycin. Development of resistance against tetracycline also appears to be significant. Variable resistance among the different members of the cephalosporin group is a factor to be investigated further since susceptibility profile against these antibiotics and interpretative criteria for oral bacteria are not available.

Prescription of Antibiotics for Periodontal Disease among Dentists in the Region of Tirana

BACKGROUND:

Periodontal disease has been and will be a challenge for dentists in the entirety of oral pathologies. To date, there is no data regarding the prescription of antibiotics for periodontitis in the district of Tirana.

AIM:

Evaluate aspects related to the pattern of prescription of antibiotics among dentists in Tirana region for periodontitis.

METHODS:

Prescriptions from dental practitioners were collected from 25 pharmacies, randomly selected. The only prescription containing a diagnosis of periodontitis, with at least one antibiotic given, was included in the study. Data analysis was done with SPSS 20.

RESULTS:

Out of 1159 initial prescriptions, only 314 met the selection criteria. The average age of patients was 39.91 ± 15.21 years. Mean duration of therapies was 5.57 ± 1.5 days. The most common form of prescription was one broad-spectrum antibiotic (74.5%), combined antibiotics therapy (22.3%) and narrow-spectrum antibiotic (3.2%). Combined antibiotics involved the use of Metronidazole with Amoxicillin (12.1%) and Metronidazole with Spiramycin (10.2%). Significant differences in the patterns of prescription were identified in relation with patient age and therapy duration (P < 0.05). No statistical difference was found in the patient’s gender and the typology of the therapy (P > 0.05).

CONCLUSIONS:

Our study shows prescription characteristics of antibiotics for periodontal disease by dentists in Tirana for the first time. Amoxycillin is the most prescribed antibiotic, followed by amoxicillin with clavulanic acid. We found variation in dosage, frequency and duration for all antibiotics used, and perceptible discrepancies between observed and recommended practice. Guidelines on rational antibiotic use are needed for dental practitioners in Tirana and the Republic of Albania for better management of periodontitis and resistance prevention.

Multiparticulate based thermosensitive intra-pocket forming implants for better treatment of bacterial infections in periodontitis

Considering alarming projections in the prevalence of periodontitis, following study was undertaken to develop chitosan-vanillin crosslinked microspheres loaded in-situ gel (MLIG) implants containing ornidazole and doxycycline hyclate for the treatment of pocket infections. Firstly, microspheres were formulated and optimized using response surface methodology for particle size <50 μm, entrapment efficiency >80%, in-vitro drug release (T_80%) >7 days and acceptable mucoadhesion. Further, MLIG were optimized for gelation temperature of 34-37 °C and viscosity <1000 cps respectively. FTIR, DSC and XRD graphs disclosed compatibility and alterations in crystallinity of drugs. In-vitro dissolution study demonstrated non-Fickian type of drug release mechanism for twelve days. Stability studies ascertained MLIG implants were sterilizable and stable for about 11.29 months on refrigeration. The formulations exhibited significant (p < 0.001) antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis, and were found biocompatible and biodegradable during preclinical studies. Ligature-induced periodontal rat model, corroborated significant growth (p < 0.05) of gingival tissue after two weeks. Clinical trials revealed, intra-pocket administration of MLIG along with SRP provided significant reduction in clinical parameters as compared to SRP alone. Conclusively, antimicrobials incorporated thermosensitive, biodegradable, mucoadhesive and syringeable MLIG implants appeared as better option for the treatment of periodontitis.

A successful antimicrobial therapeutic strategy for the discitis caused by Aggregatibacter actinomycetemcomitans under unknown drug susceptibility: A case report

Aggregatibacter actinomycetemcomitans is well-known as the pathogen of gingivitis or periodontitis, and discitis or vertebral osteomyelitis cases caused by this organism have rarely been reported. Ampicillin or amoxicillin has been used in the previously reported discitis cases; however, no cases have been reported that is treated with levofloxacin. We report the first published case we chose levofloxacin to treat. We failed to perform the susceptibility testing because of the poor growth and fastidious nature of the organism, and the result of susceptibility of amoxicillin was unclear. Levofloxacin, which A. actinomycetemcomitans is usually susceptible to, can be an effective alternative oral antimicrobial agent in such cases.

Benefits of adjunctive moxifloxacin in generalized aggressive periodontitis: a subgroup analyses in Aggregatibacter actinomycetemcomitans-positive/negative patients from a clinical trial

AIM

The aim of the present study was to evaluate the influence of the baseline detection of Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) on the clinical outcomes of moxifloxacin (MOX) as an adjunct to full-mouth scaling and root planing (SRP) in generalized aggressive periodontitis (GAgP).

METHODS

Forty patients were randomly distributed to two therapy protocols: SRP + placebo or SRP combined with MOX. A. actinomycetemcomitans was detected using culture methods. The significance of the treatment option (MOX or SRP + placebo) on the dependent variables (probing depth [PD] and clinical attachment level [CAL]), considering the interaction with the baseline detection of A. actinomycetemcomitans, was estimated.

RESULTS

MOX therapy led to a higher significant PD reduction and CAL gain in A. actinomycetemcomitans-positive patients at baseline. In A. actinomycetemcomitans-positive patients, the reduction of sites ≥5 mm was higher in the MOX group. A. actinomycetemcomitans was not present in sites with PD ≥6 mm in the MOX group. The interactions of A. actinomycetemcomitans and MOX were significantly associated with CAL gain and PD reduction at 6 months.

CONCLUSIONS

Adjunctive MOX trended toward better clinical responses in A. actinomycetemcomitans-positive patients at baseline. These results suggest that A. actinomycetemcomitans at baseline might modify the effect of adjunctive MOX in GAgP.

Comparative Evaluation of Ciprofloxacin Levels in GCF and Plasma of Chronic Periodontitis Patients: Quasi Experimental Study

INTRODUCTION

For any antimicrobial approach to be successful in periodontal therapy, it is important that the antimicrobial agent targets the sub-gingival biofilm by attaining sufficient concentration at the sub-gingival site.

AIM

The purpose of the present study was to determine and compare the concentrations of ciprofloxacin present in Gingival Crevicular Fluid (GCF) and plasma after its systemic administration.

MATERIALS AND METHODS

A total of 20 subjects, in the age group of 30-60 years satisfying the inclusion and exclusion criteria, were chosen from the outpatient Department of Periodontology, Government Dental College and Hospital, Hyderabad and consent was obtained. Subjects were put on oral ciprofloxacin therapy (Baycip, Bayer Corporation) of 500mg twice daily doses for five days to establish steady state tissue levels of the agent. GCF and serum samples were collected at the 72(nd) hour after the first dose of ciprofloxacin and were compared using unpaired t test.

RESULTS

The mean gingival index value of the subjects was 1.8 ± 0.59 and the mean probing depth of the subjects taken in the study was 5.724 ± 0.47mm. The results of this study showed that ciprofloxacin concentrations were significantly higher (p<0.001) in GCF than in plasma.

CONCLUSION

Results from the present study and those from the earlier studies clearly indicate the ciprofloxacin's ability to reach and concentrate in infected periodontal sites via GCF. This property of ciprofloxacin may be useful for eradication of periodontal pathogens, thus improving the outcome of periodontal therapy.

Clinical Efficacy of Azithromycin as an Adjunctive Therapy to Non-Surgical Periodontal Treatment of Periodontitis: A Systematic Review and Meta-Analysis

INTRODUCTION

Over the years, numerous trials have sufficiently documented benefits of adjuvant administration of antibiotics in combination to Scaling and Root Planing (SRP) in treatment of periodontitis. Nevertheless there are justified doubts in respect to antibiotics administration with regard to increasing development of resistances.

AIM

The aim of this review study and meta-analysis was to verify a possible benefit of Azithromycin (AZM) as an alternative adjuvant antibiotic in combination with SRP.

MATERIALS AND METHODS

Electronic databases (Pubmed) were searched from the earliest point of record until May 2015. A hand search was also conducted. The variables considered in this respect were Probing Depth (PD), Clinical Attachment Level (CAL), Bleeding on Probing (BOP) and SRP. A meta-analysis containing trials comparing SRP as a sole therapy with SRP and administration of AZM was produced once all of the data obtained had been reviewed.

RESULTS

Six randomised clinical trials were accepted into the review and the meta-analysis following the process of trial selection. Meta-analysis revealed larger overall effects by the systemic administration of AZM compared with SRP on their own in terms of PD, CAL, BOP, Plaque-Index and total bacterial load reduction after three and six months.

CONCLUSION

The data used in this study revealed that the systemic administration of AZM is beneficial compared with SRP on its own for the treatment of chronic periodontitis.

Development of novel electrospun dual-drug fiber mats loaded with a combination of ampicillin and metronidazole

OBJECTIVE

Our study was performed with the aim of preparing electrospun polylactide fibers with a combination of ampicillin (AMP) and metronidazole (MNZ) and investigating their drug release behavior and the antibacterial effect on Aggregatibacter actinomycetemcomitans and other oral pathogens.

METHODS

AMP and MNZ were integrated as a combination in two separate fibers (dual fiber mats - DFW mix) of electrospun PLA fiber mats by means of multijet electrospinning and in a single fiber (single fiber mats - SFW mix). HPLC (high-performance liquid chromatography) was used to measure the released drug quantities. Agar diffusion tests were used to determine the antibacterial effect of the eluates on A. actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis and Enterococcus faecalis. The neutral red test was made to examine the cytocompatibility of the eluates with human gingival fibroblasts (hGFs).

RESULTS

The release of the active agents varied with the antibiotic concentrations initially used in the fiber mats, but also with the distribution of the active agents in one or two fibers. Of the total quantity of MNZ (AMP), the SFW mix fiber mats released >60% (>70%) within a span of 5min, and 76% (71%) after 96h. With these drug concentrations released by the fiber mats (≥5m%), an antibacterial effect was achieved on A. actinomycetemcomitans and on all other species tested. Fiber mats and their eluates have no cytotoxic influence on human gingival fibroblasts (hGFs).

SIGNIFICANCE

Electrospun AMP/MNZ-loaded polymer fibers are a potential drug delivery system for use in periodontal and endodontic infections.

Microbiological and Clinical Effects of Sitafloxacin and Azithromycin in Periodontitis Patients Receiving Supportive Periodontal Therapy

Sitafloxacin (STFX) is a newly developed quinolone that has robust antimicrobial activity against periodontopathic bacteria. We previously reported that oral administration of STFX during supportive periodontal therapy was as effective as conventional mechanical debridement under local anesthesia microbiologically and clinically for 3 months. The aim of the present study was to examine the short-term and long-term microbiological and clinical effects of systemic STFX and azithromycin (AZM) on active periodontal pockets during supportive periodontal therapy. Fifty-one patients receiving supportive periodontal therapy were randomly allocated to the STFX group (200 mg/day of STFX for 5 days) or the AZM group (500 mg/day of AZM for 3 days). The microbiological and clinical parameters were examined until 12 months after the systemic administration of each drug. The concentration of each drug in periodontal pockets and the antimicrobial susceptibility of clinical isolates were also analyzed. The proportions of red complex bacteria, i.e., Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, which are the representative periodontopathic bacteria, were significantly reduced at 1 month and remained lower at 12 months than those at baseline in both the STFX and AZM groups. Clinical parameters were significantly improved over the 12-month period in both groups. An increase in the MIC of AZM against clinical isolates was observed in the AZM group. These results indicate that monotherapy with systemic STFX and AZM might be an alternative treatment during supportive periodontal therapy in patients for whom invasive mechanical treatment is inappropriate. (This study has been registered with the University Hospital Medical Information Network-Clinical Trials Registry [UMIN-CTR] under registration number UMIN000007834.).

Systemic moxifloxacin vs amoxicillin/metronidazole adjunct to non-surgical treatment in generalized aggressive periodontitis

Background

The objective of this randomized clinical study was to evaluate the effect of systemic administration of moxifloxacin compared to amoxicillin and metronidazole, combined with non-surgical treatment in patients with generalized aggressive periodontitis (GAgP) in a 6-month follow-up.

Material and Methods

A total of 39 systemically healthy patients with GAgP were evaluated in this randomized clinical trial. Periodontal parameters were recorded at the baseline during the 1st, 3rd and 6th month. Patients received either 400 mg of moxifloxacin per os once daily or 500 mg of metronidazole and 500 mg amoxicillin per os three times daily for 7 days consecutively.

Results

No significant differences between groups were found in any parameters at the baseline. Both groups led to a statistically significant decrease in all clinical periodontal parameters compared to the baseline (PI, p<0.001 and GI, PD, BOP, CAL, p<0.01). There were no differences between the 1st and 3rd months or the 3rd and 6th months for clinical parameters in the groups. Also, no intergroup difference was observed in any parameters at any time, except the gingival index at 6th months.

Conclusions

Systemic administration of moxifloxacin as an adjunct to non-surgical treatment significantly improves clinical outcomes and provides comparable clinical improvement with less adverse events to that of combination of amoxicillin and metronidazole in the treatment of GAgP.

Key words: Aggressive periodontitis, amoxicillin, metronidazole, moxifloxacin, nonsurgical periodontal debridement.

Adjunctive moxifloxacin in the treatment of generalized aggressive periodontitis patients: clinical and microbiological results of a randomized, triple-blind and placebo-controlled clinical trial

AIM

The aim of the present study was to evaluate the clinical and microbiological efficacy of moxifloxacin (MOX) in one-stage scaling and root planing (SRP) in treating generalized aggressive periodontitis (GAgP).

MATERIALS AND METHODS

Forty subjects were randomly allocated to two treatment groups. The two treatment groups consisted of SRP combined with systemically administered MOX at the dosage of 400 mg once daily for 7 days or SRP + placebo once daily for 7 days. Subgingival plaque samples were analysed for cultivable bacteria.

RESULTS

Both groups resulted in significant reduction of probing depth (PD) and clinical attachment level (CAL) compared with baseline (p < 0.0001), and this difference was maintained at 6 months from baseline in both groups. However, subjects receiving MOX showed the greatest improvements CAL, and PD. Subjects in both groups at 6 months displayed the greatest reduction from baseline in frequency of sites with PD ≥ 6 mm (p < 0.001), favouring the MOX group. Adjunctive antibiotic protocol reduced subgingival Aggregatibacter actinomycetemcomitans to undetectable levels, after 3 and 6 months, and there was a significant reduction in the levels of Porphyromonas gingivalis and Tannerella forsythia in the MOX group compared to the placebo group.

CONCLUSIONS

The results from this study suggest that moxifloxacin as and adjunct to one-stage full-mouth SRP leads to a better clinical and microbiological advantages compared to mechanical treatment.

Clinical and microbiological effects of systemic azithromycin in adjunct to nonsurgical periodontal therapy in treatment of Aggregatibacter actinomycetemcomitans associated periodontitis: a randomized placebo-controlled clinical trial

OBJECTIVE

This study aimed to evaluate clinical and microbiological effects of systemic azithromycin (AZM) in adjunct to nonsurgical periodontal therapy (NSPT; or scaling root planing - SRP) in treatment of Aggregatibacter actinomycetemcomitans associated periodontitis (AAAP).

METHODS AND MATERIALS

Seventy individuals with moderate to severe periodontitis and subgingival detection of A. actinomycetemcomitans were randomly allocated to two groups. Thirty-five individuals were allocated to full mouth SRP+AZM (500 mg oral delivery (OD) × 3 days) while 35 individuals were allocated to SRP+Placebo (OD × 3 days) group. The clinical variables evaluated were probing depth (PD), clinical attachment level (CAL), gingival index (GI), plaque index (PI), and percent bleeding on probing sites (%BOP), while microbiologic variables included percentage of subjects positive for A. actinomycetemcomitans at baseline, 3, 6, and 12 months.

RESULTS

The AZM group showed statistically significant reduction in mean PD (2.91 ± 0.88 mm) as compared to placebo (1.51 ± 0.98 mm) (P < 0.001), while CAL gain was significant in the AZM group (2.71 ± 1.15 mm) as compared to the placebo group (1.71 ± 1.29 mm) (P < 0.001). There was also a statistically significant reduction in the number of subjects positive for A. actinomycetemcomitans in the AZM group (P < 0.0001).

CONCLUSION

Azithromycin was found to significantly improve the clinical and microbiological parameters in AAAP individuals.

Diagnosis and anti-infective therapy of periodontitis

Periodontal diseases (gingivitis and periodontitis) are chronic bacterial infections with a remarkably high prevalence and morbidity. Periodontitis, in contrast to gingivitis, is not reversible, is associated with certain bacterial species and affects all of the soft tissue and bone that support teeth. Among the periodontal pathogens, species, such as Aggregatibacter (Actinobacillus) actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythensis, and several forms of uncultivable spirochetes play the major role in the pathogenesis. In severe chronic, recurrent and especially aggressive forms of periodontitis, diagnosis of the species involved and, whenever possible, an optimized evidence-based antimicrobial treatment is indicated. In order to monitor alarming bacterial changes in the periodontal pocket, several techniques, namely microscopy, culture, immunoassays, enzyme tests and DNA-based techniques, have been established and the methods are described in the first part of this review. In the second part, the selection and use of locally delivered (topical) and systemic antibiotics used adjunctively in periodontal therapy are discussed.

Aggregatibacter actinomycetemcomitans biofilm killing by a targeted ciprofloxacin prodrug

A pH-sensitive ciprofloxacin prodrug was synthesized and targeted against biofilms of the periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa). The dose required to reduce the viability of a mature biofilm of Aa by ~80% was in the range of ng cm(-2) of colonized area (mean biofilm density 2.33 × 10(9) cells cm(-2)). A mathematical model was formulated that predicts the temporal change in the concentration of ciprofloxacin in the Aa biofilm as the drug is released and diffuses into the bulk medium. The predictions of the model were consistent with the extent of killing obtained. The results demonstrate the feasibility of the strategy to induce mortality, and together with the mathematical model, provide the basis for design of targeted antimicrobial prodrugs for the topical treatment of oral infections such as periodontitis. The targeted prodrug approach offers the possibility of optimizing the dose of available antimicrobials in order to kill a chosen pathogen while leaving the commensal microbiota relatively undisturbed.

Azithromycin: a new concept in adjuvant treatment of periodontitis

In most patients periodontitis is successfully treated by scaling and root planing, but some studies have shown that certain sites continue to show periodontal tissue destruction despite conventional periodontal therapy. To solve this problem, antibiotics may be administered as an adjuvant treatment. This includes azithromycin (AZM), which is effective against Gram-negative aerobic and anaerobic bacteria and has a long half-life in periodontal tissues. The purpose of the present study was to determine the efficacy of azithromycin as an adjuvant treatment for periodontitis through a review of the literature in Medline, Lilacs and Scielo, combining the keywords "azithromycin", "periodontal treatment" and "periodontitis" in both Portuguese and English languages. To be included, articles had to be clinical trials, randomized, controlled, double-blind or blind, and published between 2001 and 2011. 70 articles were found, of which 12 were selected based on title and abstract. Most studies used AZM as an adjuvant treatment for chronic periodontitis, usually in a single daily dose of 500 mg over three days, and indicated that AZM significantly reduced probing depth and increased periodontal attachment when compared to controls. Furthermore, a reduction in red and orange complex and an increase in bacteria associated with healthy periodontal conditions were observed in subjects treated with AZM. It may be concluded that the use of AZM as an adjuvant treatment for periodontitis improves clinical and microbiological parameters when compared to conventional treatment alone.

Mechanisms of action of systemic antibiotics used in periodontal treatment and mechanisms of bacterial resistance to these drugs

Antibiotics are important adjuncts in the treatment of infectious diseases, including periodontitis. The most severe criticisms to the indiscriminate use of these drugs are their side effects and, especially, the development of bacterial resistance. The knowledge of the biological mechanisms involved with the antibiotic usage would help the medical and dental communities to overcome these two problems. Therefore, the aim of this manuscript was to review the mechanisms of action of the antibiotics most commonly used in the periodontal treatment (i.e. penicillin, tetracycline, macrolide and metronidazole) and the main mechanisms of bacterial resistance to these drugs. Antimicrobial resistance can be classified into three groups: intrinsic, mutational and acquired. Penicillin, tetracycline and erythromycin are broad-spectrum drugs, effective against gram-positive and gram-negative microorganisms. Bacterial resistance to penicillin may occur due to diminished permeability of the bacterial cell to the antibiotic; alteration of the penicillin-binding proteins, or production of β-lactamases. However, a very small proportion of the subgingival microbiota is resistant to penicillins. Bacteria become resistant to tetracyclines or macrolides by limiting their access to the cell, by altering the ribosome in order to prevent effective binding of the drug, or by producing tetracycline/macrolide-inactivating enzymes. Periodontal pathogens may become resistant to these drugs. Finally, metronidazole can be considered a prodrug in the sense that it requires metabolic activation by strict anaerobe microorganisms. Acquired resistance to this drug has rarely been reported. Due to these low rates of resistance and to its high activity against the gram-negative anaerobic bacterial species, metronidazole is a promising drug for treating periodontal infections.

What are the antibiotics of choice for odontogenic infections, and how long should the treatment course last?

In the everyday practice of oral and maxillofacial surgeons, empiric antibiotics are prescribed in the face of uncertainty. Is there a highly resistant organism present? Are the old-line antibiotics no longer effective? Should a broad-spectrum antibiotic be used just to cover all the bases in this case? The surprising result of this systematic review is that when combined with appropriate surgery, the usual antibiotics are all effective. Safety and cost become the differentiating factors in this clinical decision.

Effects of systemic sitafloxacin on periodontal infection control in elderly patients

OBJECTIVE

To evaluate the microbiological and clinical effects of the systemic administration of sitafloxacin (STFX) on periodontal pockets in elderly patients receiving supportive periodontal therapy (SPT).

BACKGROUND

Periodontitis is a risk factor for atherosclerosis. Better periodontal health contributes to reduce atherosclerosis-related diseases in elderly population.

MATERIALS AND METHODS

Forty-four patients undergoing SPT were randomly assigned to two groups: a test group took 100 mg/day of STFX for five consecutive days, or a control group received scaling and root planing (SRP) under local anaesthesia. Microbiological and clinical parameters were examined at baseline and at 1 and 3 months after therapy.

RESULTS

The presence of Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia was significantly reduced at 1 month after treatment in both groups. The median reductions of the bacteria between the baseline and 1 month were 3.08 and 2.54% in the STFX- and SRP-treated groups, respectively. Both treatments significantly decreased the probing depth at 1 and 3 months compared to the baseline.

CONCLUSION

The systemic administration of STFX is effective at improving periodontal health during SPT and could be an alternative to SRP for elderly patients who cannot undergo anaesthesia or are at risk of tissue injury.

Selective killing of Aggregatibacter actinomycetemcomitans by ciprofloxacin during development of a dual species biofilm with Streptococcus sanguinis

OBJECTIVES

Periodontal disease is associated with a pathogen-induced transition to a chronic destructive inflammatory response. Since commensals may either passively or actively contribute to immune homeostasis, therapies aimed at selectively reducing the competitive advantage of pathogens may be effective supplements to traditional methods. We developed an in vitro system to grow biofilms composed of the pathogen (Aggregatibacter actinomycetemcomitans) and the commensal (Streptococcus sanguinis). We used the biofilm model to determine the feasibility of selectively killing the pathogen using the fluoroquinolone, ciprofloxacin.

DESIGN

Biofilms were exposed to relevant ciprofloxacin doses during the first 24h of development, with subsequent removal of the ciprofloxacin for a 24h period. Biofilm growth was assessed by confocal laser scanning microscopy, crystal violet staining and DNA abundance.

RESULTS

Exposure to 0.01mg/L or 0.5mg/L ciprofloxacin significantly reduced the microcolony size and cell surface density of A. actinomycetemcomitans in the dual species biofilm over a 24h period whilst allowing uninhibited S. sanguinis biofilm formation. A. actinomycetemcomitans biofilm development was insignificant over a subsequent 24h period after removal of the ciprofloxacin indicating that A. actinomycetemcomitans cells were killed.

CONCLUSIONS

A. actinomycetemcomitans residing in a dual species biofilm with the commensal, S. sanguinis can be selectively killed, or at least rendered metabolically inactive, by treatment with ciprofloxacin. The dual species biofilm model will be a useful tool for designing in vivo studies to determine the efficacy of selective killing agents as an adjunct treatment of localized aggressive forms of periodontal disease.

Invasive infections of Aggregatibacter (Actinobacillus) actinomycetemcomitans

BACKGROUND/PURPOSE

Aggregatibacter (Actinobacillus) actinomycetemcomitans, part of the normal flora of the mouth, is frequently found in human periodontal cultures and is an important pathogen causing various invasive infections, particularly infective endocarditis. In this study, we describe the clinical course and outcome of patients with A. actinomycetemcomitans infection.

METHODS

All patients suffering invasive A. actinomycetemcomitans infections at the National Taiwan University Hospital from January 1985 to December 2004 were included in this study. Relevant data regarding clinical presentation, antimicrobial treatment and outcome of these patients were analyzed.

RESULTS

During the study period, there were 11 patients with invasive A. actinomycetemcomitans infections, including eight patients with infective endocarditis, one with osteonecrosis and two with pneumonia and chest wall lesions. Among the patients with infective endocarditis, four had prosthetic valve replacement, four suffered from rheumatic heart disease and one had undergone surgical repair of ventricular septal defect. Lesions in the oral cavity were the probable portals of entry of the microorganism, and included carious teeth, periodontitis or radiotherapy of the ear-nose-throat field, and were noted in nine patients. Transthoracic echocardiography and/or transesophageal echocardiography were performed on the patients with probable infective endocarditis but growth was demonstrated in only four of these patients. Blood culture yielded A. actinomycetemcomitans after prolonged incubation. Three isolates were resistant to penicillin and two of these were also resistant to ampicillin.

CONCLUSION

The diagnosis of invasive A. actinomycetemcomitans infection was delayed due to the indolent clinical course, non-specific presentation and slow growth of the organism. Antibiotic therapy using amoxicillin/clavulanic acid, ampicillin, ampicillin/sulbactam, ceftriaxone, clindamycin, cefotaxime, or levofloxacin was successful in all patients. None of the patients demonstrated recurrence of infection 2-36 months following treatment.

Efficacy and safety of adjunctive local moxifloxacin delivery in the treatment of periodontitis

BACKGROUND

Moxifloxacin exerts excellent antibacterial activity against most putative periodontal pathogens and has been shown to kill bacteria in biofilm and host cells.

METHODS

Patients with chronic periodontitis were randomly assigned to receive a single subgingival application of a 0.125%, 0.4%, or 1.25% moxifloxacin gel or placebo gel immediately after full-mouth scaling and root planing (SRP). Clinical efficacy measurements were assessed in sites with baseline probing depth (PD) of ≥5.4 mm at 6 weeks and 3 months and any adverse events were determined. In addition, putative periodontal pathogens and resistance of subgingival bacteria against moxifloxacin were assessed.

RESULTS

Data of 57 patients were included in the statistical analysis. In all treatment groups, the PD decreased from baseline to 3 months, with the greatest reduction seen in patients treated with moxifloxacin 0.4% (1.5 ± 0.6 mm; P = 0.023 compared to placebo), followed by patients receiving moxifloxacin 1.25% (1.2 ± 0.4), moxifloxacin 0.125% (1.1 ± 1.1), and placebo (1.0 ± 0.6). No linear trend for PD reduction with increasing moxifloxacin concentrations was found. Porphyromonas gingivalis showed the greatest reduction in prevalence among the assessed pathogens, without any significant intergroup differences. No correlation or systematic relationship between adverse events, including bacterial resistance against moxifloxacin, and the investigational gels was found.

CONCLUSIONS

In periodontal pockets with PD of ≥5.4 mm, a single subgingival administration of a 0.4% moxifloxacin gel as an adjunct to SRP may result in additional PD reduction compared to SRP alone. In addition, the investigated moxifloxacin gels seem to be safe.

Antibiotic resistance of subgingival species in chronic periodontitis patients

BACKGROUND AND OBJECTIVE

The increasing rate of resistance of microorganisms to penicillin and other antibiotics has generated concern among health authorities in Latin America. The present investigation determined the in vitro susceptibility of Porphyromonas gingivalis, Fusobacterium nucleatum, black-pigmented Prevotella spp. and Aggregatibacter actinomycetemcomitans to metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin and moxifloxacin in patients with chronic periodontitis.

MATERIAL AND METHODS

Subgingival plaque samples from patients with periodontitis were collected and cultured on selective and nonselective culture media. The antimicrobial susceptibility of periodontopathogenic isolates was studied in chronic periodontitis patients in Colombia. Metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin and moxifloxacin were tested on all bacterial isolates and the percentage of resistant strains was calculated.

RESULTS

Of the 150 bacteria identified, 51 were P. gingivalis, 45 were black-pigmented Prevotella spp., 36 were F. nucleatum and 18 were A. actinomycetemcomitans. All the isolates were sensitive to amoxicillin/clavulanic acid and to moxifloxacin, but exhibited variable susceptibility patterns to the other antimicrobial agents tested.

CONCLUSION

The results of the present study suggest that periodontal microorganisms in patients with chronic periodontitis can be resistant to the antimicrobial agents commonly used in anti-infective periodontal therapy. We suggest that the indiscriminate use of antimicrobials could result in the appearance of more highly antibiotic-resistant strains of bacteria associated with periodontal diseases in our population compared with the populations of other countries.

Antimicrobial susceptibility of moxifloxacin against gram-negative enteric rods from colombian patients with chronic periodontitis

BACKGROUND

Gram-negative enteric rods were associated with periodontal diseases in several populations. The association between enteric and putative periodontal pathogens has received little attention in the literature. The present investigation determined the occurrence and in vitro antimicrobial susceptibility of isolates of Gram-negative enteric rods from Colombian patients with chronic periodontitis.

METHODS

Clinical parameters and the in vitro antimicrobial sensitivity of isolates of Gram-negative enteric rods were examined in 76 patients with chronic periodontitis in Medellin, Colombia. Subgingival samples were processed using culture and biochemical tests for the detection of periodontal and superinfecting pathogens. Selected colonies of Gram-negative enteric rods from pure cultures were used to test the susceptibility to amoxicillin/clavulanic acid, ciprofloxacin, and moxifloxacin. Chi-square and Mann-Whitney tests were used to determine differences in clinical variables versus the presence or absence of Gram-negative enteric rods.

RESULTS

Klebsiella pneumoniae was found in 12 patients, Pseudomonas aeruginosa was found in four patients, and three other species were recovered with a lower prevalence. Men (38.75%) tended to harbor more of the studied organisms than women (17.7%) (P = 0.04). Gram-negative enteric rods in periodontal pockets correlated positively with the presence of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, and Prevotella intermedia/nigrescens (respectively, r = 0.66, 0.31, and 0.32; P <0.001). All superinfecting organisms demonstrated a high susceptibility to moxifloxacin and ciprofloxacin but exhibited a variable susceptibility to amoxicillin/clavulanic acid.

CONCLUSIONS

This study found high levels of Gram-negative enteric rods in patients with chronic periodontitis. Moxifloxacin and ciprofloxacin appeared capable of eradicating these organisms from periodontal pockets. Its good activity against Gram-negative enteric rods and periodontopathogens suggests the potential use of moxifloxacin as an adjunctive antibiotic in the treatment of mixed periodontal infections.

[Antibiotic therapy in odontogenic infections in children and adolescents: pharmacokinetic/pharmacodynamic analysis]

INTRODUCTION

The objective of this study was to evaluate the efficacy of the most commonly used antimicrobial treatments in odontogenic infections in children and adolescents on the basis of pharmacokinetic/ pharmacodynamic (PK/PD) criteria.

METHODS

Unbound drug plasma concentration-time curves were simulated with mean population pharmacokinetic parameters of amoxicillin, co-amoxiclav, cefuroxime axetil, spiramycin, clindamycin, azithromycin, and metronidazole. For drugs showing time-dependent antibacterial killing, the time above MIC90 of the pathogens studied was calculated (T>MIC). For drugs with concentration-dependent bactericidal activity, the area under the concentration-time curve (AUC)/MIC90 ratio was calculated.

RESULTS

Adequate efficacy indexes (T>MIC>40%) against all the microorganisms examined with the exception of Veillonella spp. were obtained with co-amoxiclav (80 mg/kg/day). Clindamycin (40 mg/kg/day) obtained adequate PK/PD indexes except for Lactobacillus, Actinobacillus actinomycetemcomitans, penicillin-resistant Peptostreptococcus, and Eikenella corrodens. High-dose amoxicillin yielded unsatisfactory results against many bacterial species. Azithromycin and metronidazole showed inadequate efficacy indexes against the majority of pathogens studied (AUC/MIC90<25).

CONCLUSION

When antibiotic therapy is needed for odontogenic infections in children and adolescents, the most active empirical therapeutic choice is co-amoxiclav with high doses of amoxicillin. Clindamycin can be used as an alternative option. These results should be confirmed in clinical trials, in which the PK/PD approach could be useful for the design and assessment of results.

Effect of adjunctive systemic azithromycin with periodontal surgery in the treatment of chronic periodontitis in smokers: a pilot study

BACKGROUND

Along with conventional surgical therapy, systemic antibiotics may provide more effective treatment in smokers by targeting tissue-invasive bacteria. The aim of this randomized, placebo-controlled, double-masked clinical trial was to evaluate the adjunctive effects of systemic azithromycin (AZM) in combination with periodontal pocket reduction surgery in the treatment of chronic periodontitis in smokers.

METHODS

Thirty patients with a greater than one pack/day smoking habit and generalized moderate to severe chronic periodontitis were randomized to the test (surgery plus 3 days of AZM, 500 mg) or control group (surgery plus 3 days of placebo). Full-mouth probing depth (PD), clinical attachment level (CAL), bleeding on probing (BOP), gingival index (GI), plaque index, and wound healing indices (WHI) were assessed at baseline and at 2 weeks and 1, 3, and 6 months following surgical intervention. Plaque and gingival crevicular fluid were collected for trypsin-like enzyme activity (benzoyl-dl-arginine naphthylamine) and bone biomarker (crosslinked telopeptide of type I collagen [ICTP]) analyses, respectively, at baseline, 2 weeks, and 1, 3, and 6 months.

RESULTS

Surgical treatment of moderate (PD = 4 to 6 mm) and deep (PD > 6 mm) pockets significantly improved clinical parameters of treated and untreated teeth (CAL gain, PD reduction, and reduction of BOP). The additional use of AZM did not enhance this improvement nor did it promote reduction of ICTP levels. Compared to the control group, the test group had significantly better WHI scores at 1 month, significantly less GI at 2 weeks, and sustained reductions of red-complex bacteria with trypsin-like enzyme activity at 3 months. For non-surgery teeth, only the test group showed significant gains in overall CAL compared to baseline.

CONCLUSIONS

The findings of this pilot study demonstrated that in heavy smokers, adjunctive systemic AZM in combination with pocket reduction surgery did not significantly enhance PD reduction or CAL gain. However, the clinical value of adjunctive AZM may be appreciated by more rapid wound healing, less short-term gingival inflammation, and sustained reductions of periopathogenic bacteria. More expanded studies are recommended to better determine the clinical effects of adjunctive AZM in patients who smoke.

Photodynamic therapy for periodontal diseases: State of the art

BACKGROUND

Photodynamic killing of periodontopathogenic bacteria may be an alternative to the systemic application of antibacterial drugs used in the treatment of periodontal diseases. Even though the method is still in the experimental stage, increasing bacterial resistance problems may promote the introduction of photodynamic therapy (PDT) into periodontal practice.

AIM

In this review a literature survey is given of PDT as seen from a periodontal perspective.

METHODS

In this review, the present knowledge and experience of PDT is summarized. Literature data are presented on drawbacks of conventional antibiotics, the mechanism of PDT, bactericidal effects of PDT as well as results of clinical efforts. The future prospects of the method are discussed.

RESULTS

The application of photosensitizing dyes and their excitation by visible light enables effective killing of periodontopathogens. Encouraging studies using PDT in periodontitis and in peri-implantitis are known.

CONCLUSION

Even though PDT is still in experimental stages of development and testing, the method may be an adjunct to conventional antibacterial measures in periodontology. Clinical follow-up studies are needed to confirm the efficacy of the procedure.

Serum and gingival crevicular fluid levels of ciprofloxacin in patients with periodontitis

BACKGROUND

The use of antibiotics as an adjunctive therapy in the treatment of periodontal diseases is of special interest to dental practitioners. In addition to using an appropriate antibacterial agent, clinicians may find it useful to determine the local and systemic concentrations of antibiotics in infected periodontal sites to reduce the levels of bacteria. The purpose of this study was to determine the serum and gingival crevicular fluid, or GCF, concentrations of systemic ciprofloxacin in patients with periodontitis.

METHODS

Ten subjects with chronic periodontitis received ciprofloxacin (500 milligrams) twice daily for five days. The authors collected GCF and serum samples immediately after administering the first dose (baseline = 0 hours) and at consecutive time points. The orifice method was used for GCF sampling, and 5 milliliters of venous blood was drawn for serum analysis. The authors used high-performance liquid chromatography to determine ciprofloxacin concentrations in GCF and serum.

RESULTS

The authors found that ciprofloxacin concentrations in GCF were significantly higher than concentrations in serum at two, four, seven, 24 and 120 hours. Ciprofloxacin reached the maximum concentration, or Cmax (3.72 micrograms/ mL), in GCF two hours after the initial dose was administered. The concentration decreased to 2.06 microg/mL 24 hours after the initial administration of the drug. Serum Cmax was 2.58 microg/mL at 1.5 hours, and the concentration decreased to 0.26 microg/mL at 24 hours.

CONCLUSION

The results of this clinical study show that ciprofloxacin is found in GCF and its concentration in GCF is significantly higher than that in serum.

CLINICAL IMPLICATIONS

Ciprofloxacin may be useful in treating patients with periodontitis because it reaches higher concentrations in GCF than in serum.

Drug interactions in dentistry

BACKGROUND

The hepatic and intestinal cytochrome, or CY, P450 enzyme system is responsible for the biotransformation of a multitude of drugs. Certain medications used in dentistry can act as substrates, inducers or inhibitors of this system.

METHODS

The authors conducted a MEDLINE search of articles appearing between 1976 and the present using the keywords "drug interactions" and "cytochrome P450," and reviewed reports involving dental therapeutic agents using PubMed links from an Indiana University CYP450 drug interaction table on the World Wide Web.

RESULTS

The antibiotics erythromycin and clarithromycin are potent inhibitors of CYP3A4 and can increase blood levels and toxicity of CYP3A4 substrates. Likewise, quinolone antibiotics such as ciprofloxacin inhibit the metabolism of CYP1A2 substrates. Other dental therapeutic agents are substrates for CYP2C9 (celecoxib, ibuprofen and naproxen), CYP2D6 (codeine and tramadol), CYP3A4 (methylprednisolone) and CYP2E1 (acetaminophen). Because codeine and tramadol are prodrugs, inhibition of their metabolism can lead to a diminution of their analgesic effects. While inducers of acetaminophen metabolism, including alcohol, theoretically can increase the proportion of it that is biotransformed into a potentially hepatotoxic metabolite, recent research suggests that concomitant alcohol intake does not increase the hepatotoxic potential of therapeutic doses of acetaminophen.

CONCLUSIONS

A number of clinically significant drug interactions can arise with dental therapeutic agents that act as substrates or inhibitors of the CYP450 system. Clinical Implications. As polypharmacy continues to increase, the likelihood of adverse drug interactions in dentistry will increase as well. Ensuring that patients' medical histories are up to date and acquiring knowledge of the various substrates, inducers and inhibitors of the CYP450 system will help practitioners avoid potentially serious adverse drug interactions.