Abstract Encapsulation of amoxicillin (AMC) with ethyl cellulose (EC) by a supercritical antisolvent process (SAS) was investigated. AMC microparticles obtained previously by an SAS process were used as host particles and EC, a biodegradable polymer used for the controlled release of drugs, was chosen as the coating material. In this work, a suspension of AMC microparticles in a solution of ethyl cellulose in dichloromethane (DCM) was sprayed through a nozzle into supercritical CO2. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and HPLC analyses were carried out. The effects of AMC:EC ratio, the initial polymer concentration of the solution, temperature and pressure on the encapsulation process were investigated. Although all the experiments led to powder precipitation, the AMC encapsulation was achieved in only half of the cases, particularly when the lower drug:polymer ratios were assayed. In general, it was observed that the percentages of AMC present in the precipitates were higher on increasing the AMC:EC ratio. In these cases composites rather than encapsulates were obtained. The in vitro release profiles of the resulting materials were evaluated in order to ascertain whether composites can be used as encapsulated systems for drug delivery systems.

Enterococcus faecalis (E. faecalis) has become a major leading cause of nosocomial endocarditis. Treatment of such infections remains problematic and new therapeutic options are needed. Nine E. faecalis strains were tested: six obtained from patients presenting endocarditis, one with isolated bacteremia, and two reference strains. Antibiotics included daptomycin, alone or in combination, linezolid, tigecycline, rifampicin, gentamicin, teicoplanin, ceftriaxone and amoxicillin. Time-kill studies included colony counts at 1, 4 and 24 h of incubation. Significant bactericidal activity was defined as a decrease of ≥3log10CFU/ml after 24 h of incubation. Antibiotics were tested at a low (10(6) CFU/ml) and high (10(9) CFU/ml) inoculum, against exponential- and stationary-phase bacteria. We also performed time kill studies of chemically growth arrested E. faecalis. Various pH conditions were used during the tests. In exponential growth phase and with a low inoculum, daptomycin alone at 60 µg/ml and the combination amoxicillin-gentamicin both achieved a 4-log10 reduction in one hour on all strains. In exponential growth phase with a high inoculum, daptomycin alone was bactericidal at a concentration of 120 µg/ml. All the combinations tested with this drug were indifferent. In stationary phase with a high inoculum daptomycin remained bactericidal but exhibited a pH dependent activity and slower kill rates. All combinations that did not include daptomycin were not bactericidal in conditions of high inoculum, whatever the growth phase. The results indicate that daptomycin is the only antibiotic that may be able of overcoming the effects of growth phase and high inoculum.

Oxcarbazepine (OXC) is generally accepted as a drug without risk of severe drug-induced hepatotoxicity, but according to recently reported pharmacovigilance data this statement has been challenged. However, in the literature there have been no reports of acute OXC-induced hepatotoxicity without systemic manifestations of Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) syndrome. We present a female with seizures one month after delivery who had borderline elevated liver enzymes prior to the initiation of OXC treatment. Two weeks after introducing OXC, highly elevated liver enzymes were found. After discontinuation of OXC the enzymes continued to rise for another week, and afterward gradually decreased. The causal relationship with OXC intake was determined to be highly probable. Two years later, the transitory elevation of liver enzymes was observed during the treatment of acute tonsilopharingitis with amoxicillin + clavulanic acid. The repeated elevation of liver enzymes related to use of different drugs might indicate patients susceptibility for drug induced liver injuries. We suggest that monitoring of liver function tests would be clinically rational for early detection of acute OXC-induced liver hepatotoxicity in the patients with clinical and/or laboratory features which might be interpreted as possible risk factors of the increased susceptibility to drug induced liver injuries.

OBJECTIVES:

To compare the antimicrobial susceptibility of Prevotella spp. isolated from cystic fibrosis (CF) and non-CF patients and analyse the impact of antibiotic prescribing in the preceding year on resistance amongst CF isolates.

METHODS:

The susceptibility of 80 CF Prevotella isolates to 12 antibiotics was compared with that of 50 Prevotella isolates from invasive infections in people who did not have CF and 27 Prevotella isolates from healthy controls.

RESULTS:

All isolates were susceptible to chloramphenicol, meropenem and piperacillin/tazobactam, with only four isolates resistant to metronidazole. However, resistance to amoxicillin, ceftazidime and tetracycline was apparent in all groups. Significant differences in clindamycin resistance (UK CF, 56%; UK invasive, 10%) and co-amoxiclav non-susceptibility (UK CF, 32%; UK invasive, 12%) were observed between UK CF and UK invasive isolates. The likelihood of non-susceptibility to clindamycin and co-amoxiclav in UK CF isolates was 5.5-fold and 2.5-fold higher relative to that in UK invasive isolates, respectively. Azithromycin MICs were also significantly higher for CF isolates (P < 0.001), which was associated with current prescription of azithromycin. More than 50% of clinical isolates tested in this study were β-lactamase positive.

CONCLUSIONS:

This study profiles antibiotic susceptibility in Prevotella spp. in CF and demonstrates that meropenem, piperacillin/tazobactam, chloramphenicol and metronidazole are likely to be the most effective antibiotics if treatment is indicated.

OBJECTIVE:

To investigate the effect of the microbiota-induced changes and early overfeeding after amoxicillin administration (a) in suckling pups via their dams up to 15 days of lactation and (b) in weaned pups on intestinal microbial/functional adaptability and obesity development in male Sprague-Dawley rats.

DESIGN AND METHODS:

Postnatal nutrition was elicited by adjusting the number of pups in the nest to 4 (small litters [SLs]) and 10 (normal litters [NLs]), while from days 21 to 40, both groups were fed with a standard diet. The numbers of Bacteroides/Prevotella (BAC) and Lactobacillus/Enterococcus (LAB) in the jejunum and colon were determined by fluorescence in situ hybridization technique, and jejunal alkaline phosphatase (AP), α-glucosidase and aminopeptidase activity was assayed histochemically.

RESULTS:

On day 40, the SL in comparison with NL animals displayed excess weight/fat gain accompanied by higher LAB and lower numbers of BAC, and with permanently higher AP activity. Moreover, these acquired changes continued in SL vs. NL rats and were not influenced by antibiotic treatment, which induced significant decrease in the quantity of LAB and BAC.

CONCLUSIONS:

These findings highlight the role of early life overfeeding upon the gut microbial/functional ontogeny and allow to distinguish their potential involvement in later risk of obesity.

PURPOSE:

Eradication rates following standard triple therapy for Helicobacter pylori infection are declining. Recent studies, conducted in a number of countries, have shown that sequential therapy for H. pylori infection yields high cure rates.

AIM:

To compare the efficacy and tolerability of a sequential regimen as a first-line treatment of H. pylori infection with a standard triple treatment regime in Morocco.

METHODS:

A total of 281 naive H. pylori-infected patients, confirmed by histological examination, were assigned randomly to one of two treatment groups: standard triple therapy [omeprazole (20 mg bid) + amoxicillin (1 g bid) + clarithromycin (500 mg bid) for 7 days] or sequential therapy [omeprazole (20 mg bid) + amoxicillin (1 g bid) for 5 days, followed by omeprazole (20 mg bid) + tinidazole (500 mg bid) + clarithromycin (500 mg bid) for an additional 5 days]. H. pylori eradication was checked 4-6 weeks after treatment initiation by using a (13)C-urea breath test. Compliance and adverse events were assessed.

RESULTS:

The two groups did not differ significantly in gender, age, previous disease history, endoscopic and histological features and smoking. The intention-to-treat and per-protocol eradication rates were 65.9 and 71 % in the standard triple therapy group, and 82.8 and 89.9 % in the sequential therapy group, respectively. The eradication rate was significantly higher in the sequential therapy group than in the standard triple therapy group (p < 0.001), There was no statistically significant difference in compliance (97.5  vs. 96.3 %) and incidence of side-effects (27.5 vs. 27.9 %) between the two groups.

CONCLUSIONS:

Based on our results, we conclude that for eradication of H. pylori infection, the 10-day sequential therapy is more effective than the standard triple therapy and is equally tolerated. These results confirm those of other studies in other countries.

PURPOSE:

: Our goals are to test the effect of acute lung infection on tumor metastasis and to investigate the underlying mechanisms. EXPERIMENTAL

DESIGN:

We combined bacteria- and lipopolysaccharide (LPS)-induced acute lung injury/inflammation (ALI) mouse models with mouse metastatic models to study the effect of acute inflammation on lung metastasis in mice. The mechanisms were invested in ex vivo, in vitro, and in vivo studies.

RESULTS:

Both bacteria- and LPS-induced acute lung injury/inflammation significantly enhanced lung metastasis of four tail vein-injected mouse tumor cell lines. Bacteria also enhanced lung metastasis when 4T1 cells orthotopically injected. The broncheoalveolar lavage fluid (BALF) from LPS- or bacteria- injected mice stimulated migration of tumor cells. In vivo tracking of metastatic RM-9 cells showed that bacterial injection enhanced early dissemination of tumor cells to the lung. The majority of the BALF migratory activity could be blocked by AMD3100, a CXCR4 inhibitor. All tested cell lines expressed CXCR4. The levels of extracellular ubiquitin (Ub), but not SDF-1, in BALF were significantly increased by LPS. Ub was able to induce AMD3100-sensitive migration of tumor cells. Finally, the anti-bacterial amoxicillin and AMD3100 blocked the enhancement effect of bacterial infection on tumor metastasis.

CONCLUSIONS:

Acute lung infection dramatically increased cancer cell homing to the lung and lung metastasis. This may be due to an alteration of the lung microenvironment and preparation of a favorable metastatic "niche". This effect was seen in multiple cancer types and thus may have broad applications for cancer patients in prevention and/or treatment of metastasis.

Background:

Chronic periodontitis patients may yield multiple species of putative periodontal bacterial pathogens that vary in their antibiotic drug susceptibility. This study determined the occurrence of in vitro antibiotic resistance among selected subgingival periodontal pathogens in chronic periodontitis patients.

Methods:

Subgingival biofilm specimens from inflamed deep periodontal pockets were removed prior to treatment from 400 adults in the United States with chronic periodontitis. The samples were cultured, and selected periodontal pathogens tested in vitro for susceptibility to amoxicillin at 8 mg/L, clindamycin at 4 mg/L, doxycycline at 4 mg/L, and metronidazole at 16 mg/L, with a post-hoc combination of data for amoxicillin and metronidazole. Gram-negative enteric rods/pseudomonads were subjected to ciprofloxacin disk diffusion testing.

Results:

Overall, 74.2% of the periodontitis patients revealed subgingival periodontal pathogens resistant to at least one of the test antibiotics. One or more test species, most often Prevotella intermedia/nigrescens, Streptococcus constellatus or Aggregatibacter actinomycetemcomitans, were resistant in vitro to doxycycline, amoxicillin, metronidazole, or clindamycin, in 55%, 43.3%, 30.3%, and 26.5% of the chronic periodontitis patients, respectively. 15% of patients harbored subgingival periodontal pathogens resistant to both amoxicillin and metronidazole, which were mostly either S. constellatus (45 persons) or ciprofloxacin-susceptible strains of gram-negative enteric rods/pseudomonads (nine persons).

Conclusions:

Chronic periodontitis patients in the United States frequently yielded subgingival periodontal pathogens resistant in vitro to therapeutic concentrations of antibiotics commonly utilized in clinical periodontal practice. The wide variability found in periodontal pathogen antibiotic resistance patterns should concern clinicians empirically selecting antibiotic treatment regimens for chronic periodontitis patients.