Charlotta Edlund

Antibiotic administration is known to cause short-term disturbances in the microbiota of the human gastrointestinal tract, but the potential long-term consequences have not been well studied. The aims of this study were to analyse the long-term impact of a 7-day clindamycin treatment on the faecal microbiota and to simultaneously monitor the ecological stability of the microbiota in a control group as a baseline for reference. Faecal samples from four clindamycin-exposed and four control subjects were collected at nine different time points over 2 years. Using a polyphasic approach, we observed highly significant disturbances in the bacterial community that persisted throughout the sampling period. In particular, a sharp decline in the clonal diversity of Bacteroides isolates, as assessed by repetitive sequence-based PCR (rep-PCR) and long-term persistence of highly resistant clones were found as a direct response to the antibiotic exposure. The Bacteroides community never returned to its original composition during the study period as assessed using the molecular fingerprinting technique, terminal restriction fragment length polymorphism (T-RFLP). Furthermore, using real-time PCR we found a dramatic and persistent increase in levels of specific resistance genes in DNA extracted from the faeces after clindamycin administration. The temporal variations in the microbiota of the control group were minor compared to the large and persistent shift seen in the exposed group. These results demonstrate that long after the selection pressure from a short antibiotic exposure has been removed, there are still persistent long term impacts on the human intestinal microbiota that remain for up to 2 years post-treatment.

Although it is known that antibiotics have short-term impacts on the human microbiome, recent evidence demonstrates that the impacts of some antibiotics remain for extended periods of time. In addition, antibiotic-resistant strains can persist in the human host environment in the absence of selective pressure. Both molecular- and cultivation-based approaches have revealed ecological disturbances in the microbiota after antibiotic administration, in particular for specific members of the bacterial community that are susceptible or alternatively resistant to the antibiotic in question. A disturbing consequence of antibiotic treatment has been the long-term persistence of antibiotic resistance genes, for example in the human gut. These data warrant use of prudence in the administration of antibiotics that could aggravate the growing battle with emerging antibiotic-resistant pathogenic strains.

Metronidazole has been used for the treatment of infections for >45 years and is still successfully used for the treatment of trichomoniasis, amoebiasis, and giardiasis. Anaerobic bacterial infections caused by Bacteroides species, fusobacteria, and clostridia respond favorably to metronidazole therapy. Good clinical results in the treatment of vaginosis due to Gardnerella vaginalis have also been reported. Rates of resistance to metronidazole are still generally low; however, several studies have reported decreased susceptibility among Bacteroides species, as well as different mechanisms of resistance. Metronidazole-resistant Helicobacter pylori strains have been described, but combination therapy (eg, metronidazole, amoxicillin, or clarithromycin plus omeprazole) is still recommended for eradication of this pathogen in patients with gastroduodenal ulcers. Metronidazole is considered to be a cost-effective drug because of its low cost, good activity against pathogenic anaerobic bacteria, favorable pharmacokinetic and pharmacodynamic properties, and minor adverse effects. Metronidazole is still the criterion standard for therapy of anaerobic infections, as was described by Tally and colleagues 35 years ago.

PURPOSE: Public health insurance programs have expanded coverage for the poor, and family physicians provide essential services to these vulnerable populations. Despite these efforts, many Americans do not have access to basic medical care. This study was designed to identify barriers faced by low-income parents when accessing health care for their children and how insurance status affects their reporting of these barriers. METHODS: A mixed methods analysis was undertaken using 722 responses to an open-ended question on a health care access survey instrument that asked low-income Oregon families, "Is there anything else you would like to tell us?" Themes were identified using immersion/crystallization techniques. Pertinent demographic attributes were used to conduct matrix coded queries. RESULTS: Families reported 3 major barriers: lack of insurance coverage, poor access to services, and unaffordable costs. Disproportionate reporting of these themes was most notable based on insurance status. A higher percentage of uninsured parents (87%) reported experiencing difficulties obtaining insurance coverage compared with 40% of those with insurance. Few of the uninsured expressed concerns about access to services or health care costs (19%). Access concerns were the most common among publicly insured families, and costs were more often mentioned by families with private insurance. Families made a clear distinction between insurance and access, and having one or both elements did not assure care. Our analyses uncovered a 3-part typology of barriers to health care for low-income families. CONCLUSIONS: Barriers to health care can be insurmountable for low-income families, even those with insurance coverage. Patients who do not seek care in a family medicine clinic are not necessarily getting their care elsewhere.