amoxicillin-potassium-clavulanate-combination and Bacteroides-Infections

In an open, randomized study of 60 patients with acute or recurrent sinusitis, the bacteriological and clinical efficacy of roxithromycin 150 mg bd were compared with those of po co-amoxiclav (625 mg) tds. Of 52 patients who underwent sinus puncture for isolation of causative organisms, 48 had pathogens sensitive to both antibiotics. Satisfactory clinical response was obtained in 93.1% (27/29) evaluable patients receiving roxithromycin and 88.8% (24/27) receiving co-amoxiclav. Tolerability was significantly better in the roxithromycin group, with 1/29 (3.4%) patients in this group experiencing gastrointestinal side-effects, compared with 7/27 (25.9%) patients in the co-amoxiclav group (P < 0.05). Although the study had limited power to detect differences, roxithromycin demonstrated clinical, bacteriological and overall efficacy similar to that of co-amoxiclav, but with better tolerability. Roxithromycin thus appears to be an effective and well-tolerated drug for the treatment of acute and recurrent sinusitis.

Topics: Adolescent; Adult; Aged; Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteroides fragilis; Bacteroides Infections; Drug Therapy, Combination; Female; Haemophilus Infections; Haemophilus influenzae; Humans; Male; Middle Aged; Moraxella catarrhalis; Neisseriaceae Infections; Pneumococcal Infections; Roxithromycin; Sinusitis; Staphylococcal Infections; Streptococcus pneumoniae

Repeatedly, too low MIC results were obtained in Bacteroides fragilis quality assessment strains, using gradient strip tests with a ratio of amoxicillin:clavulanic acid of 2:1. We aimed to find the most accurate available gradient strip tests for susceptibility testing of amoxicillin/clavulanic acid in B. fragilis in comparison with agar dilution with EUCAST methodology and breakpoints.. Twenty-seven clinical B. fragilis isolates were investigated using gold standard EUCAST amoxicillin/clavulanic acid agar dilution (fixed clavulanic acid concentration at 2 mg/L, with increasing amoxicillin concentrations) as well as three commercial gradient strip tests: XL (ratio), AUG (ratio) or AMC (fixed concentration).. Using agar dilution (fixed concentration), 19 isolates were susceptible, 1 isolate was susceptible increased exposure (I) and 7 isolates were resistant. Categorical agreement of the gradient strip tests with agar dilution (fixed concentration) was 70% for XL (ratio), 71% for AUG (ratio) and 89% for AMC (fixed concentration). Very major error rates in comparison with agar dilution (fixed concentration) were 100%, 0%, and 0%, respectively.. EUCAST breakpoint usage in amoxicillin/clavulanic acid susceptibility tests for B. fragilis should be accompanied by EUCAST methodology. When using alternative methods such as gradient strip tests, a higher degree of alignment with EUCAST methodology, such as using fixed clavulanic acid concentrations, improves precision.

Topics: Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteroides fragilis; Bacteroides Infections; Genetic Variation; Genotype; Humans; Microbial Sensitivity Tests; Reagent Strips

Some strains of Bacteroides fragilis species are associated with diarrhea as a result of enterotoxin production (bft or fragilysin). Fragilysin is activated by C11 protease (fpn) and together with C10 protease (bfp) play a significant role in its invasiveness. The objectives of this study were to investigate the proportion of clinical isolates from extra-intestinal sources that are toxin producers and characterize the genes mediating toxin production. Clinical isolates submitted to our reference laboratory over the last 13 years were screened for toxin production using PCR technique. All stool isolates were excluded. The isolates were tested for their susceptibility to 8 antimicrobial agents by E test. Carbapenem resistance gene cfiA was detected by PCR.. A total of 421 B. fragilis isolates were viable. Out of these, bft was detected in 210 (49.9%) isolates. Of the 210 bft-positive isolates, 171 (81.4%), 33 (15.7%) and 6 (2.8%) harbored bft-1, bft-2, and bft-3 genes, respectively. Twenty (9.5%) of the bft-positive strains originated from bloodstream infections. Twenty-five, 20 and 9 strains harbored bfp-1, bfp-2 and bfp-3 gene, respectively. Two, 3, 4 bfp isotypes were detected simultaneously in some of strains. The resistance rates against amoxicillin-clavulanic acid was 32%, clindamycin 62%, cefoxitin 26%, imipenem 11%, meropenem 17%, metronidazole 4%, piperacillin 61% and tigecycline 14%. A chromosomally located cfiA gene that encode metallo-β-lactamase was identified in only 34 isolates (16.2%).. The prevalence of enterotoxin-producing B. fragilis was high among the extra-intestinal isolates. Metronidazole was the most active agent against all isolates. There was no statistically significance difference between resistance rates among bft-positive and bft-negative isolates except for clindamycin.

Topics: Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacterial Toxins; Bacteroides fragilis; Bacteroides Infections; Cefoxitin; Clindamycin; Drug Resistance, Bacterial; Feces; Female; Humans; Imipenem; Kuwait; Male; Meropenem; Metronidazole; Microbial Sensitivity Tests; Piperacillin; Prevalence; Prospective Studies; Respiratory Tract Infections; Sepsis; Tigecycline; Wound Infection

The species of the Bacteroides fragilis group are important components of human microbiota, but as opportunistic pathogens they can be the causative agents of severe infections.. The major aims of our investigation were the evaluation of the susceptibility of 400 different Hungarian B. fragilis group isolates to 10 antibiotics by the agar dilution method, the comparison of our resistance data with previous national and international antibiotic resistance data and the comparison of present data in regional aspect. The MIC-values on 10 antibiotics of all the strains were determined with the agar dilution method by CLSI. The presence of the cfiA gene in Division II B. fragilis strains was confirmed by RT-PCR.. We detected a relatively high resistance rate of ampicillin, moxifloxacin, clindamycin and tetracycline, but amoxicillin/clavulanic acid, metronidazole, tigecycline and chloramphenicol showed excellent activity. In this study, we found that 6.75% of the isolates were resistant to cefoxitin and 7% to meropenem, while 8.58% of our B. fragilis strains harboured the cfiA gene. Most of the meropenem resistant strains were isolated in one of the participating centres. In the case of meropenem, cefoxitin, clindamycin and high-level-ampicillin-resistant strains, we found significant regional differences.. Most of the results of our study were concordant with previous national and international data, with the exception of amoxicillin/clavulanic acid, cefoxitin and meropenem.. Our study highlighted the importance of the periodic monitoring of the antimicrobial susceptibility of Bacteroides species providing important information for the appropriate therapy.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Amoxicillin-Potassium Clavulanate Combination; Ampicillin; Anti-Bacterial Agents; Bacteroides; Bacteroides Infections; beta-Lactamases; Child; Child, Preschool; Female; Humans; Hungary; Imipenem; Male; Microbial Sensitivity Tests; Middle Aged; Polymerase Chain Reaction; Surveys and Questionnaires; Young Adult

Topics: Actinomycetaceae; Actinomycetales Infections; Aged; Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteremia; Bacteroides fragilis; Bacteroides Infections; Catheter-Related Infections; Coinfection; Female; Gardnerella vaginalis; Gram-Positive Bacterial Infections; Humans; Klebsiella Infections; Klebsiella oxytoca; Leg Ulcer; Pressure Ulcer; Skin; Soft Tissue Infections; Species Specificity; Urinary Catheterization; Urinary Tract Infections

Clinical isolates of the Bacteroides fragilis group (n = 387) were collected from patients attending nine Canadian hospitals in 2010-2011 and tested for susceptibility to 10 antimicrobial agents using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. B. fragilis (59.9%), Bacteroides ovatus (16.3%), and Bacteroides thetaiotaomicron (12.7%) accounted for ~90% of isolates collected. Overall rates of percent susceptibility were as follows: 99.7%, metronidazole; 99.5%, piperacillin-tazobactam; 99.2%, imipenem; 97.7%, ertapenem; 92.0%, doripenem; 87.3%, amoxicillin-clavulanate; 80.9%, tigecycline; 65.9%, cefoxitin; 55.6%, moxifloxacin; and 52.2%, clindamycin. Percent susceptibility to cefoxitin, clindamycin, and moxifloxacin was lowest for B. thetaiotaomicron (n = 49, 24.5%), Parabacteroides distasonis/P. merdae (n = 11, 9.1%), and B. ovatus (n = 63, 31.8%), respectively. One isolate (B. thetaiotaomicron) was resistant to metronidazole, and two isolates (both B. fragilis) were resistant to both piperacillin-tazobactam and imipenem. Since the last published surveillance study describing Canadian isolates of B. fragilis group almost 20 years ago (A.-M. Bourgault et al., Antimicrob. Agents Chemother. 36:343-347, 1992), rates of resistance have increased for amoxicillin-clavulanate, from 0.8% (1992) to 6.2% (2010-2011), and for clindamycin, from 9% (1992) to 34.1% (2010-2011).

Topics: Adolescent; Adult; Aged; Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteroides; Bacteroides fragilis; Bacteroides Infections; Canada; Clindamycin; Drug Resistance, Multiple, Bacterial; Female; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Population Surveillance

Topics: Abdominal Abscess; Amoxicillin-Potassium Clavulanate Combination; Animals; Anti-Bacterial Agents; Bacteroides fragilis; Bacteroides Infections; Cephamycins; Disease Models, Animal; Escherichia coli; Escherichia coli Infections; Humans; Mice; Sepsis; Treatment Outcome

A blood-culture isolate of Bacteroides fragilis, taken from a woman after elective laparotomy, was resistant to metronidazole and had reduced susceptibility to imipenem and co-amoxiclav. After treatment with imipenem, pus drained from the pleural cavity yielded an identical isolate that had become highly resistant to imipenem and co-amoxiclav. Emergence of full resistance to the beta-lactam antibiotics was accompanied by a tenfold rise in the specific activity of a metallo-beta-lactamase. Clinicians need to be alert to simultaneous resistance to metronidazole, co-amoxiclav, and imipenem and development of high-level resistance to imipenem in B fragilis during treatment with this agent.

Topics: Adult; Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Bacteremia; Bacteroides fragilis; Bacteroides Infections; Clavulanic Acids; Drug Resistance, Microbial; Drug Resistance, Multiple; Drug Therapy, Combination; Empyema, Pleural; Female; Humans; Imipenem; Metronidazole

Topics: Adult; Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Bacteroides Infections; Clavulanic Acids; Drug Therapy, Combination; Eikenella corrodens; Humans; Male; Osteomyelitis; Radiography; Spinal Diseases

Topics: Amoxicillin-Potassium Clavulanate Combination; Animals; Anti-Bacterial Agents; Bacteroides fragilis; Bacteroides Infections; Disease Models, Animal; Escherichia coli Infections; Mice

The efficacy of amoxycillin/clavulanic acid was compared with those of metronidazole, cefuroxime, metronidazole/ampicillin, metronidazole/gentamicin and metronidazole/cefuroxime, in experimental mixed infections produced in mice by subcutaneous inoculation of amoxycillin-resistant strains of Bacteroides fragilis and Escherichia coli. The combination of metronidazole/ampicillin failed to inhibit the growth of E. coli, and exerted only a transient effect on the numbers of Bact. fragilis in the groin abscesses. In contrast, amoxycillin/clavulanic acid prevented the development of the infection, eliminating both organisms. Metronidazole and cefuroxime, alone and in combination, were less effective than amoxycillin/clavulanic acid in inhibiting the growth of the infecting organisms. These results demonstrate the clinical potential of amoxycillin/clavulanic acid in prophylaxis, or in the therapy of mixed aerobe/anaerobe infections.

Topics: Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Ampicillin; Animals; Anti-Bacterial Agents; Bacteroides fragilis; Bacteroides Infections; Cefuroxime; Clavulanic Acids; Drug Combinations; Escherichia coli; Escherichia coli Infections; Female; Gentamicins; Metronidazole; Mice

The therapeutic effects produced by formulations of amoxicillin plus clavulanic acid (BRL 25 000A and BRL 25 000G) were compared with those of amoxicillin and clavulanic acid separately against a variety of infections produced by amoxicillin-susceptible and beta-lactamase-producing (amoxicillin-resistant) bacteria. The infection models studied included intraperitoneal infections, a mouse pneumonia, experimental pyelonephritis, and local lesions caused by Staphylococcus aureus and Bacteroides fragilis. The distribution of amoxicillin and clavulanic acid in infected animals after the administration of amoxicillin-clavulanic acid was evaluated by measurement of the concentrations of the substances present in specimens collected at the sites of infection. The results showed that both amoxicillin and clavulanic acid were well distributed in the animal body after the administration of amoxicillin-clavulanic acid formulations, being present in significant concentrations at various sites of infection, e.g., peritoneal washings, pleural fluid, pus, and infected tissue homogenates. In a number of cases, the amoxicillin concentrations measured after the administration of BRL 25000 were higher than those found after treatment with amoxicillin alone, presumably as a result of inhibition of bacterial beta-lactamases by clavulanic acid at the site of infection. The ability of clavulanic acid to protect amoxicillin in vivo was confirmed by the efficacy of amoxicillin-clavulanic acid formulations in the treatment of the infections studied, most of which were refractory to therapy with amoxicillin.

Topics: Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Animals; Anti-Bacterial Agents; Bacterial Infections; Bacteroides Infections; Clavulanic Acids; Drug Combinations; Mice; Pneumonia, Staphylococcal; Pyelonephritis