A Panel of International Experts was convened by the Infectious Diseases Society of America (IDSA) in collaboration with the European Society for Microbiology and Infectious Diseases (ESCMID) to update the 1999 Uncomplicated Urinary Tract Infection Guidelines by the IDSA. Co-sponsoring organizations include the American Congress of Obstetricians and Gynecologists, American Urological Association, Association of Medical Microbiology and Infectious Diseases-Canada, and the Society for Academic Emergency Medicine. The focus of this work is treatment of women with acute uncomplicated cystitis and pyelonephritis, diagnoses limited in these guidelines to premenopausal, non-pregnant women with no known urological abnormalities or co-morbidities. The issues of in vitro resistance prevalence and the ecological adverse effects of antimicrobial therapy (collateral damage) were considered as important factors in making optimal treatment choices and thus are reflected in the rankings of recommendations.

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International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases

Most antibiotic resistance mechanisms are associated with a fitness cost that is typically observed as a reduced bacterial growth rate. The magnitude of this cost is the main biological parameter that influences the rate of development of resistance, the stability of the resistance and the rate at which the resistance might decrease if antibiotic use were reduced. These findings suggest that the fitness costs of resistance will allow susceptible bacteria to outcompete resistant bacteria if the selective pressure from antibiotics is reduced. Unfortunately, the available data suggest that the rate of reversibility will be slow at the community level. Here, we review the factors that influence the fitness costs of antibiotic resistance, the ways by which bacteria can reduce these costs and the possibility of exploiting them.

Antibiotic resistance and its cost: is it possible to reverse resistance?

Evidence-based guidelines for the management of patients with Lyme disease, human granulocytic anaplasmosis (formerly known as human granulocytic ehrlichiosis), and babesiosis were prepared by an expert panel of the Infectious Diseases Society of America. These updated guidelines replace the previous treatment guidelines published in 2000 (Clin Infect Dis 2000; 31[Suppl 1]:1-14). The guidelines are intended for use by health care providers who care for patients who either have these infections or may be at risk for them. For each of these Ixodes tickborne infections, information is provided about prevention, epidemiology, clinical manifestations, diagnosis, and treatment. Tables list the doses and durations of antimicrobial therapy recommended for treatment and prevention of Lyme disease and provide a partial list of therapies to be avoided. A definition of post-Lyme disease syndrome is proposed.

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The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America

Structural Mechanism for Rifampicin Inhibition of Bacterial RNA Polymerase

Current methods for differentiating isolates of predominant lineages of pathogenic bacteria often do not provide sufficient resolution to define precise relationships. Here, we describe a high-throughput genomics approach that provides a high-resolution view of the epidemiology and microevolution of a dominant strain of methicillin-resistant Staphylococcus aureus (MRSA). This approach reveals the global geographic structure within the lineage, its intercontinental transmission through four decades, and the potential to trace person-to-person transmission within a hospital environment. The ability to interrogate and resolve bacterial populations is applicable to a range of infectious diseases, as well as microbial ecology.

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Evolution of MRSA During Hospital Transmission and Intercontinental Spread

Mutations of the rpoB gene conferring resistance to rifampin were analyzed in 40 methicillin-resistant Staphylococcus aureus isolates obtained from six countries. Interestingly, the majority of clinical isolates showed multiple mutations within rpoB. The amino acid substitution 481His→Asn was the most prevalent one, capable of conferring low-level resistance on its own. Cross-resistance to rifampin, rifabutin, and rifapentine was demonstrated for all mutants identified. The level of resistance to rifamycins correlated with both the mutation position and type of amino acid substitution.

Molecular characterization of rpoB mutations conferring cross-resistance to rifamycins on methicillin-resistant Staphylococcus aureus.

Resistance determinants that interfere with normal physiological processes in the bacterial cell usually cause a reduction in biological fitness. Fitness assays revealed that 17 of 18 in vitro-selected chromosomal mutations within the rpoB gene accounting for rifampin resistance in Staphylococcus aureus were associated with a reduction in the level of fitness. There was no obvious correlation between the level of resistance to rifampin and the level of fitness loss caused by rpoB mutations. Among 23 clinical rifampin-resistant S. aureus isolates from six countries, only seven different rpoB genotypes could be identified, whereby the mutation 481His→Asn was present in 21 (91%) of these 23 isolates. The mutation 481His→Asn, in turn, which confers low-level rifampin resistance on its own, was not shown to be associated with a cost of resistance in vitro. The restriction to distinct mutations that confer rifampin resistance in vivo, as demonstrated here, appears to be determined by the Darwinian fitness of the organisms.

Biological Cost of Rifampin Resistance from the Perspective of Staphylococcus aureus

Prospective Multicenter Study Evaluating Fecal Calprotectin in Adult Acute Bacterial Diarrhea

The in vitro release of vancomycin, teicoplanin, gentamicin and clindamycin from biodegradable calcium sulphate (CaSO(4)) carrier beads is described. All antibiotics showed prolonged release from the carrier beads, which was elevated during the first 24 h, with peak levels exceeding 2500 microg/bead. Doubling the antibiotic load of the beads revealed a more prolonged elution and a two-fold increase in antibiotic release. Local carrier-associated antibiotic treatment with CaSO(4) beads may prove to be effective in the management of chronic bone infections.

Elution characteristics of vancomycin, teicoplanin, gentamicin and clindamycin from calcium sulphate beads

Oral mucositis is a frequent complication of radiochemotherapy. The origin of radiation-induced mucosal lesions is iatrogenic in nature, although further development of mucositis is essentially influenced by infection. It can be assumed that disinfection measures should decrease the severity of mucositis induced by radiochemotherapy. Therefore, in a prospective randomised study the efficacy of prophylactic oral rinsing with a disinfection agent was investigated. A randomised, prospective comparative trial was conducted with 40 patients undergoing radiochemotherapy of the head and neck region because of malignant disease. The treatment scheme consisted of irradiation to the tumour region and adjacent lymph nodes, with a total dose of 71.3 Gy, and simultaneous chemotherapy with carboplatin (60 mg/m2) on days 1–5 and 29–34. In all patients mucositis prophylaxis with nystatin, rutosides, panthenol and immunoglobulin was undertaken. In addition, 20 patients rinsed the oral cavity 4 times daily with povidone-iodine solution, while the group for comparison rinsed with sterile water. Clinical examination of the oral mucosa was performed weekly. Onset, grading and duration of mucositis were used as the main variables. Clinically manifest oral mucositis was observed in 14 patients in the iodine group (mean grading: 1.0) and in all 20 patients in the control group (mean grading: 3.0). The total duration (mean) of clinically observed mucositis was 2.75 weeks in treatment patients and 9.25 weeks in control patients. Median AUC (area under curve for grade vs duration) was 2.5 in the iodine rinsing patients and 15.75 in control patients. All differences found between the two groups were statistically significant. Increased iodine incorporation was not observed. A pathologic rise in thyroid hormone levels was not found in the iodine group. The results obtained indicate that incidence, severity and duration of radiochemotherapy-induced mucositis can be significantly reduced by oral rinsing with povidone-iodine in addition to the standard prophylaxis scheme. It can be concluded that rinsing with povidone-iodine is an easy, cheap and safe prophylactic method and can be recommended as a supportive treatment during antineoplastic treatment of the head and neck region.

V. Schäfer

Papers

Molecular characterization of rpoB mutations conferring cross-resistance to rifamycins on methicillin-resistant Staphylococcus aureus.

Biological Cost of Rifampin Resistance from the Perspective of Staphylococcus aureus

Prospective Multicenter Study Evaluating Fecal Calprotectin in Adult Acute Bacterial Diarrhea

Elution characteristics of vancomycin, teicoplanin, gentamicin and clindamycin from calcium sulphate beads

Prophylaxis with povidone-iodine against induction of oral mucositis by radiochemotherapy.