SummaryIron, an essential nutrient for most microorganisms, is sequestered by the host to decrease the concentration of iron available to bacterial pathogens. Neisseria gonorrhoeae, the causative agent of gonorrhoea, can acquire iron by direct interaction with human ironbinding proteins, including the serum glycoprotein, transferrin. Iron internalization from host transferrin requires the expression of a bacterial receptor, which specifically recognizes the human form of transferrin. Two gonococcal transferrin-binding proteins have been implicated in transferrin receptor function, TbpA and TbpB. We constructed a gonococcal transferrin receptor mutant without the introduction of additional antibiotic resistance markers and tested its ability to cause experimental urethritis in human male volunteers. The transferrin receptor mutant was incapable of initiating urethritis, although the same inoculum size of the wild-type parent strain, FA1090, causes urethritis in >90% of inoculated volunteers. To our knowledge, this is the first experimental demonstration that a bacterial iron acquisition system is an essential virulence factor for human infection.

Streptococcus pneumoniae strains have exhibited decreasing susceptibility to penicillins and macrolides during the past several years. We reviewed the medical charts of all patients with pneumococcal bacteremia who were admitted to a university hospital over a period of 1 year, to identify failures of outpatient therapy. Of 41 patients admitted with pneumococcal bacteremia, 4 had previously taken either azithromycin or clarithromycin for 3-5 days. All 4 had pneumococcal strains that exhibited low-level resistance to macrolide antibiotics. Among pneumococci, low-level resistance to macrolides can lead to clinical failure, and resistance to macrolides should be considered during the selection of empiric therapy for patients with presumed pneumococcal infections.

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We conducted a multicenter, retrospective cohort study of patients with Streptococcus pneumoniae bacteremia to determine factors associated with antibiotic resistance and mortality. Risk factors were identified using multivariate logistic regression. 1,574 patients at 34 sites were enrolled. Compared to isolates from patients not receiving an antibiotic before the index blood culture, patients receiving an antibiotic were less likely to harbor an antibiotic susceptible organism. Susceptibility to penicillin decreased from 78% (95% confidence interval [CI], 75−80) to 49% (95%CI, 39−59); to cefotaxime/ ceftriaxone, from 92% (95%CI, 90−93) to 82% (95%CI, 72−89); and to macrolide, from 84% (95% CI, 82−87) to 55% (95%CI, 41−68). Factors associated with macrolide non-susceptibility include: >24 hours of antibiotic therapy at time of the index culture (odds ratio [OR] 4.0), residing in southern U.S. (OR 1.7), and having an antibiotic allergy (OR 1.7). Harboring an antibiotic non-susceptible strain (OR 1.4) and male sex (OR 1.4) were associated with increased risk of mortality, whereas Black race (OR 0.6) and evidence of focal infection (OR 0.6) were associated with decreased risk.

Antimicrobial resistance to penicillin and macrolides in Streptococcus pneumoniae has increased in the United States over the past decade. Considerable geographic variation in susceptibility necessitates regional resistance tracking. Traditional active surveillance is labor intensive and costly. We collected antibiogram reports from North Carolina hospitals and assessed pneumococcal susceptibility to multiple agents from 1996 through 2000. Susceptibility in North Carolina was consistently lower than the national average. Aggregating antibiogram data is a feasible and timely method of monitoring regional susceptibility patterns and may also prove beneficial in measuring the effects of interventions to decrease antimicrobial resistance.

Background: Antimicrobial resistance in common respiratory tract pathogens is a growing public health threat, especially in the southeastern United States. The excessive use of antibiotics for common infections is a major contributing factor in the emergence of antibiotic resistance. We report results from a multi-site outpatient pilot project in North Carolina to reduce antibiotic prescriptions for acute nonbacterial upper respiratory tract infections (URIs).Methods: Primary care practices were provided education and symptom therapy kits for patients with URIs, as an alternative to antibiotics, in a project to reduce the overuse of antimicrobial therapy. The feasibility of this approach was evaluated with interviews and surveys. A methodology for claims-based evaluation of intervention efficacy in reduction of antibiotics use was developed as part of this project.Results: Of eight contacted practices, four agreed to participate and three participated fully. Physicians reported that symptom therapy kits were useful for patients with URIs and resulted in a meaningful change in antibiotic prescribing behaviors. A claims-based approach is a feasible and promising method to evaluate efficacy in subsequent post-pilot large-scale implementations.Limitations: Due to the small number of outpatient practices and the lack of controls in this pilot study, the efficacy of the intervention in reducing antibiotic use could not be determined.Conclusions: Education combined with symptom therapy kits as an alternative to oral antibiotics is a feasible intervention that warrants additional studies to evaluate the efficacy of this approach in the reduction of antibiotic use for URIs.

Background: North Carolina and the southeastern United States have the highest antimicrobial resistance rates for common respiratory tract pathogens in the nation. The excessive use of antibiotics for common outpatient infections is a major contributing factor in the emergence of antibiotic resistant bacteria. Objective: To estimate the prevalence of oral antibiotic treatment for acute, nonbacterial respiratory tract infections among adult Medicaid recipients in North Carolina, and to describe a pilot project aimed at reducing the prevalence of oral antibiotic treatment among this population.

2016-11-15T19:40:59