The in vitro adsorption of some antibiotics on antacids.

The adsorption of oxytetracycline hydrochloride, tetracycline hydrochloride, doxycycline hyclate, triacetyloleandomycin, chloramphenicol, ampicillin, and cloxacillin sodium was studied on various antacids namely, magnesium trisilicate, magnesium oxide, calcium carbonate, bismuth oxycarbonate, aluminium hydroxide, and kaolin. The adsorption of the various antibiotics by milk was also tested as milk is frequently used as an antacid. Charcoal was included in the present study as a model adsorbent having a large hydrophobic surface. The adsorption of the various antibiotics on the different antacids and other adsorbents in most cases obeyed the Freundlich adsorption isotherm. Magnesium trisilicate and magnesium oxide showed the highest adsorptive capacity, relative to other antacids used, for most antibiotics. Calcium carbonate and aluminium hydroxide and intermediate power while kaolin and bismuth oxycarbonate had the least adsorptive power. Charcoal exhibited a marked adsorption for all antibiotics tested. Tetracyclines were found to be more highly adsorbed than other antibiotics studied. Triacetyloleandomycin and chloramphenicol had intermediate values. Ampicillin was only adsorbed to a slight extent while cloxacillin was not adsorbed on the antacids used. The extent of adsorption was correlated to the structure of both the adsorbent and adsorbate, the pH of the adsorbent suspension, and to the polarity of the antibiotic in such pH. The reversibility of the adsorption process was studied in different media and at pH values similar to those of the gastrointestinal tract. The extent of elution was found to be inversely proportional to the adsorptive capacity of the different adsorbents. In general, 0.0143 n NaHCO3 solution was found to possess higher eluting properties than 0.01 n HCl. An exception to this pattern was observed with tetracyclines adsorbed on aluminium hydroxide where the elution with acid resulted in a higher degree of desorption. Careful in vitro and in vivo testing of drug availability is advisable prior to the concomitant administration of antibiotics with antacids or other adsorbents

Sequential intravenous/oral antibiotic vs. continuous intravenous antibiotic in the treatment of pyogenic liver abscess.

AIM: Pyogenic liver abscesses result in substantial morbidity and mortality. Antimicrobial regimens using sequential intravenous/oral therapy may reduce the length of hospital stay. In this retrospective analysis, the efficacy of continuous intravenous antibiotic therapy (group I) vs. sequential intravenous/oral antibiotic therapy (group II) was studied in patients with pyogenic liver abscess. METHODS: One hundred and twelve consecutive patients (55 in group I and 57 in group II) with pyogenic liver abscess were analysed. Clinical response, length of hospital stay and relapse rates were examined. RESULTS: Group II had a significantly shorter duration of intravenous antibiotic treatment (3.2 weeks vs. 5.9 weeks, P < 0.01) and a shorter length of hospital stay (28 days vs. 42 days, P < 0.01) when compared to group I. Oral antibiotics were prescribed for a median duration of 2.9 weeks in group II after discharge. No relapse occurred within 6 weeks after the completion of treatment in both groups. The cost of therapy was significantly lower in group II than in group I by 33%. CONCLUSIONS: A sequential intravenous/oral antibiotic regime is a safe and effective treatment for pyogenic liver abscess. This reduces the cost of therapy and the length of hospital stay

Aetiology of shigellosis in northern Pakistan.

People of northern Pakistan face health hazards because of poor sanitation practices. Bacterial gastrointestinal infections are very common, and sometimes outbreaks occur. The present study was aimed at evaluating and analyzing infestation of Shigella spp. in patients with suspected gastroenteritis and ascertaining the status of antibiotic therapy. Five hundred and eighty-five faecal samples of patients with suspected gastroenteritis, referred to the District Headquarter Hospital Gilgit, were investigated for common enteropathogenic bacteria from July 1997 to September 1999. Seventy-seven (13.2%) of the faecal specimens were infected with different strains of Shigella spp., 61% of which were Shigella dysenteriae, 15.6% were S. flexneri, and 23.4% were Shigella sp. All Shigella strains were sensitive to ceftriaxone, cefotaxime, ciprofloxacin, and enoxacin. Sixty-one percent of the strains were resistant to both ampicillin and chloramphenicol, and 3.9% to ampicillin and nalidixic acid, while 10.4% were resistant to ampicillin alone and 14.3% to chloramphenicol only. Only 10.4% of the strains were sensitive to all the antibiotics tested. Sixty strains of Shigella spp. were processed for isolation of plasmids, and 58 (97%) of these antibiotic-resistant bacteria harboured at least one plasmid. The number of plasmids varied from 1 to 9. Escherichia coli C600 were transformed with the isolated plasmids. Transformants, containing 23-kb plasmid, resisted growth in media containing antibiotics, thereby indicating that antibiotic resistance is plasmid-borne. Based on the findings of the study, it is concluded that the infestation of Shigella spp. is high in northern Pakistan, the aetiological agents are highly resistant to chloramphenicol and ampicillin, and the antibiotic resistance is mediated by the 23-kb plasmid

What are the non-biomedical reasons which make family doctors over-prescribe antibiotics for upper respiratory tract infection in a mixed private/public Asian setting?

OBJECTIVES: To examine the non-biomedical reasons which make family doctors over-prescribe antibiotics for upper respiratory tract infection (URTI) in a mixed private/public Asian setting. METHODS: The questionnaire was sent to the members of the Hong Kong College of Family Physicians between August and December 2001. RESULTS: A total of 801 family doctors completed a postal questionnaire with an overall response rate of 65.0. A significant number of respondents (21.8) felt they might be prescribing antibiotics too often for URTI but the majority of them felt they were using antibiotics just a bit too often. Doctors who were older, more senior or in private practice were more likely to feel that they might be prescribing antibiotics too often. More than 50 of respondents thought that to satisfy the patient or his/her carer and fear of medicolegal problem if the patient deteriorates would make them very likely or likely to over-prescribe antibiotics for patients with URTIs. Public doctors might over-prescribe in order to save time, whereas private doctors might do so in order to keep patients in their practice. CONCLUSION: The results showed that doctors with certain characteristics are more likely to over-prescribe antibiotics. Factors, other than biomedical ones, may play important roles in doctor's prescription of antibiotics for URTI