Antibiotic susceptibility of bacteria commonly isolated from the upper respiratory tract

A review of the microbiology of amoxycillin/clavulanic acid over the 15 year period 1978-1993

A review of the published literature over the period 1978-1993 was undertaken to assess any changes in the prevalence of beta-lactamase-producing bacterial pathogens and also any changes in the susceptibility in these pathogens to amoxycillin/clavulanate. The review has involved the examination of over 1500 publications. The review shows that in general there has been an increase in the frequency of beta-lactamase-producing pathogens resistant to ampicillin and amoxycillin but there is no evidence for any significant increase in resistance to amoxycillin/clavulanate over the period of the review.

Treatment of sinus empyema in adults. A coordinated Nordic multicenter trial of cefixime vs. cefaclor

In sinus empyema, H. influenzae is the most prevalent pathogen in some subpopulations and in case of therapeutic failure. Cefixime, the first oral cephalosporin of the 3rd generation, is highly potent in vitro against H. influenzae. To study the efficacy and safety of cefixime in adults with acute sinusitis, a coordinated, double-blind multicenter trial was designed for purulent cases, as confirmed by antral aspiration. A total of 364 patients were enrolled in the study with 125 cases randomized to the reference group, assigned to treatment with cefaclor. Evaluation was based on clinical outcome and on antral reaspiration (86% of the cases). No significant differences between the treatment groups were found, as regards short-term or long-term clinical outcome. However, the clinical examination overestimated the therapeutic results. Only 4% of the patients were considered as failures, but the re-aspiration demonstrated remaining suppuration in 14% of all cases (p less than 0.001). Based on re-aspiration, the failure rate among patients with initial growth of pathogens was lower for cefixime (8%) than for cefaclor (20%) (p less than 0.05). Such a difference was not found among patients with growth of H. influenzae. No serious adverse reactions were recorded, but loose stools and diarrhoea were significantly more frequent in the cefixime treatment group. Five patients (2%) in the cefixime treatment group discontinued their treatment due to adverse events.

Increased use of erythromycin causes resistance in Haemophilus influenzae

The use of erythromycin in Sweden has increased since 1975. An increasing prevalence of Haemophilus influenzae (H.i.) with reduced susceptibility to erythromycin has been noted in our laboratory during the years 1980 to 1985. The largest consumers of erythromycin were found to be children less than 4 years of age. Variations in resistance level of H.i. isolated from patients within this age group and variations in consumption of erythromycin were analysed for each year. The highest prevalence of resistant strains was found during spring and summer. The consumption of the antibiotic was highest during the first quarter of the year, gradually decreasing, and increasing sharply again during the fourth quarter of the year. Judging also from deviations from this pattern there seems to be an association between consumption and resistance. The different levels of resistance reported in the literature may reflect different populations of patients with different consumption of erythromycin, and different levels at different time of the year. Considering the present high level of H.i. with decreased susceptibility to erythromycin the drug is not likely to have clinical effect in H.i. infections.

The bactericidal activity of ampicillin, amoxicillin, tetracycline, and doxycycline against H. influenzae under various conditions of culture

The bactericidal activities of ampicillin, amoxicillin, tetracycline, and doxycycline at a concentration of 1 mg/l were compared for 13 strains of H. influenzae with a typical minimal inhibitory concentration of these drugs. Conditions of culture used were: liquid medium in shaken flasks, stationary flasks and stationary tubes, with and without the addition of 30% human serum. Ampicillin and amoxicillin exerted the same bactericidal activity. Survival rates at 5 h were on the average near 1%, however, with large variations. At 24 h survival rate was uniformly below 0.12%. The bactericidal activity of the tetracyclines depended more on the cultural conditions. A marked reduction of the bacterial population below 1% was found at 24 h between 12 of 12 and 5 of 13 strains according to the experimental circumstances. Tetracycline was more bactericidal than doxycycline, especially in the presence of serum.