Benedikt Huttner

Characteristics and outcomes of public campaigns aimed at improving the use of antibiotics in outpatients in high-income countries

The worldwide increase in resistance to antimicrobial drugs has made reducing the unnecessary use of antibiotics a public health priority. There have been campaigns in many countries to educate the public about appropriate use of antibiotics in outpatients. By use of a comprehensive search strategy and structured interviews, we were able to identify and review the characteristics and outcomes of 22 campaigns done at a national or regional level in high-income countries between 1990 and 2007. The intensity of the campaigns varied widely, from simple internet to expensive mass-media campaigns. All but one campaign targeted the public and physicians simultaneously. Most campaigns that were formally evaluated seemed to reduce antibiotic use. The effect on resistance to antimicrobial drugs cannot be assessed accurately at present. Although the most effective interventions and potential adverse outcomes remain unclear, public campaigns can probably contribute to more careful use of antibiotics in outpatients, at least in high-prescribing countries.

Local birefringence measurements in single-mode fibers with coherent optical frequency-domain reflectometry

Measurements of intrinsic and induced birefringence of optical fibers are performed at 1550 nm using the optical frequency-domain reflectometry technique. The experiment confirms the theoretical analysis, which predicts the appearance of oscillations on the detected Rayleigh backscattering intensity, with periods equal to the polarization beat length L/sub b/ and to L/sub b//2. Polarization mode-coupling length values are obtained from local birefringence and polarization mode dispersion measurements.

Modelling the impact of antibiotic use on antibiotic-resistant Escherichia coli using population-based data from a large hospital and its surrounding community

OBJECTIVES To determine the temporal relationship between antibiotic use and incidence of antibiotic-resistant Escherichia coli in both the inpatient and outpatient setting of a large urban area. METHODS A retrospective observational time-series analysis was performed to evaluate the incidence of non-duplicate clinical isolates of E. coli resistant to ciprofloxacin, trimethoprim/sulfamethoxazole and cefepime from January 2000 through December 2007, combined with a transfer function model of aggregated data on antibiotic use in both settings obtained from the hospitals pharmacy and outpatient billing offices. RESULTS Ciprofloxacin resistance increased from 6.0% (2000) to 15.4% (2007; P<0.0001) and cefepime resistance from 0.9% (2002) to 3.2% (2007; P=0.01). Trimethoprim/sulfamethoxazole resistance remained stable (23.7%-25.8%). Total antibiotic use increased in both settings, while fluoroquinolone use increased significantly only among outpatients. A temporal effect between fluoroquinolone resistance in community E. coli isolates and outpatient use of ciprofloxacin (immediate effect and time lag 1 month) and moxifloxacin (time lag 4 months) was observed, explaining 51% of the variance over time. The incidence of cefepime resistance in E. coli was correlated with ciprofloxacin use in the inpatient (lag 1 month) and outpatient (lag 4 months) settings and with the use of ceftriaxone (lag 0 month), piperacillin/tazobactam (3 months) and cefepime (3 months) in the hospital (R2=51%). CONCLUSIONS These results support efforts to reduce prescribing of fluoroquinolones for control of resistant E. coli including extended-spectrum β-lactamase producers and show the added value of time-series analysis to better understand the interaction between community and hospital antibiotic prescribing and its spill-over effect on antibiotic resistance.

Control of methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of nosocomial infections worldwide. Different approaches to the control of this pathogen have met with varying degrees of success in different health care settings. Controversies exist with regards to various MRSA control strategies. The implementation and outcomes of control measures depend on several factors, including scientific, economic, administrative, governmental, and political influences. It is clear that flexibility to adapt and institute these measures in the context of local epidemiology and resources is required.

Decolonization of intestinal carriage of extended-spectrum β-lactamase-producing Enterobacteriaceae with oral colistin and neomycin: a randomized, double-blind, placebo-controlled trial

OBJECTIVES Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are an increasingly frequent cause of infections in the community and the healthcare setting. In this study, we aimed to investigate whether intestinal carriage of ESBL-E can be eradicated. METHODS We conducted a double-blind, randomized, placebo-controlled, single-centre trial to assess the efficacy of an oral decolonization regimen on intestinal ESBL-E carriage in adult patients with an ESBL-E-positive rectal swab. Fifty-eight patients were allocated 1 : 1 to either placebo or colistin sulphate (50 mg 4×/day) and neomycin sulphate (250 mg 4×/day) for 10 days plus nitrofurantoin (100 mg 3×/day) for 5 days in the presence of ESBL-E bacteriuria. The primary outcome was detection of ESBL-E by rectal swab 28 ± 7 days after the end of treatment. Missing primary outcome data were imputed based on the last available observation. Additional cultures (rectal, inguinal and urine) were taken on day 6 of treatment and on days 1 and 7 post-treatment. The study protocol has been registered with ClinicalTrials.gov (NCT00826670). RESULTS Among 54 patients (27 in each group) included in the primary analysis, there was no statistically significant difference between the groups with regard to the primary outcome [14/27 (52%) versus 10/27 (37%), P = 0.27]. During treatment and shortly afterwards, there was significantly lower rectal ESBL-E carriage in the treatment group: 9/26 versus 19/22 on day 6 of treatment (P < 0.001) and 8/25 versus 20/26 on day 1 post-treatment (P = 0.001). This effect had disappeared by day 7 post-treatment (18/27 versus 17/25, P = 0.92). Liquid stools were more common in the treatment group (7/27 versus 2/29, P = 0.05). CONCLUSIONS The regimen used in this study temporarily suppressed ESBL-E carriage, but had no long-term effect.

Optical frequency domain reflectometry with a narrow linewidth fiber laser

The present a new optical frequency domain reflectometer based on a tunable fiber laser with a very narrow linewidth (about 10 kHz). This instrument performs reflectivity measurements with -110 dB sensitivity and 80 dB dynamic range. The narrow linewidth allows long-range measurements, at 150 m, with a spatial resolution of 16 cm. At short range, about 5 m, the resolution increases to subcentimeter.

Methicillin-resistant Staphylococcus aureus control in the 21st century: beyond the acute care hospital.

Purpose of review To describe new trends in the epidemiology of methicillin-resistant Staphylococcus aureus in the community, among animals and in long-term care settings and to discuss potential infection control implications. Recent findings Healthcare-associated methicillin-resistant S. aureus rates have decreased in several European countries. Community-associated methicillin-resistant S. aureus is spreading quickly in many parts of the world; however, its prevalence and molecular epidemiology varies considerably from continent to continent. Only few intervention studies have been published examining preventive strategies to control community-associated methicillin-resistant S. aureus transmission in the community. Although current North-American guidelines neither recommend contact tracing nor systematic decontamination with topical regimens, anecdotal evidence from several European countries suggests that these strategies could be useful in containing community-associated methicillin-resistant S. aureus. The spread of community-associated methicillin-resistant S. aureus in the healthcare setting is an emerging problem that needs early recognition and aggressive control measures, as proposed in several recent outbreak reports. Whether the increasing animal methicillin-resistant S. aureus reservoir also poses a threat to human health needs further investigation. Summary The spectrum of methicillin-resistant S. aureus epidemiology is extending into new populations. The impact on healthcare of this worrisome development has been documented in several studies. Implications for long-term methicillin-resistant S. aureus control strategies are yet unclear and need further study.

Risk factors for methicillin-resistant Staphylococcus aureus surgical site infection.

We prospectively evaluated 46 possible risk factors for methicillin-resistant Staphylococcus aureus (MRSA) surgical site infection (SSI) among patients with MRSA carriage in a large intervention study. Of 6,130 study patients, 68 (1.1%) developed MRSA SSI, which occurred a median of 14 days after surgery. Risk factors associated with MRSA SSI were receipt of emergency surgery, presence of comorbid condition, receipt of immunosuppressive therapy, receipt of contaminated surgery, and a surgical duration longer than the 75th percentile. MRSA carriage on admission did not predict MRSA SSI.

Impact of the French campaign to reduce inappropriate ambulatory antibiotic use on the prescription and consultation rates for respiratory tract infections

OBJECTIVES To assess long-term trends in the volume of ambulatory antibiotic prescriptions and prescription and consultation rates for respiratory tract infections (RTIs) in France in relation to the yearly public antibiotic campaign since 2002. METHODS Data collected on representative cohorts of office-based physicians and pharmacies in France participating in IMS Health panels between 1980 and 2009 were analysed retrospectively. Main outcome measures were antibiotic prescriptions per 1000 inhabitants per year (PIY), consultations per 1000 inhabitants per year and proportion of consultations resulting in antibiotic prescriptions. RESULTS The peak in ambulatory antibiotic prescriptions occurred in 1997 (1468 PIY). Although prescriptions had decreased by 6% until 2001, prescriptions fell sharply (-22%) between 2001 and 2004, followed by stable prescription rates until 2009. The 2001-09 decrease in antibiotic prescriptions was driven by a sharp decline in office-based antibiotic prescriptions (-33%), exclusively achieved through a decrease in prescriptions for RTIs. Consultations for RTIs steadily declined between 2001 and 2009 (-23%), with the proportion of consultations resulting in antibiotic prescriptions decreasing from 58% to 46%. Not all types of RTIs were equally affected. The largest decrease in prescriptions was observed for nasopharyngitis and influenza. Rates for bronchitis, sinusitis, otitis media and tonsillitis remained persistently high. CONCLUSIONS During its first 3 years, the French public campaign accelerated a pre-existing decrease in ambulatory antibiotic prescriptions. The decrease in consultation rates suggests that altered illness behaviour of patients may have contributed to the observed decline. The persistently high prescribing rates for certain RTIs show that further effort is needed to improve antibiotic prescribing in France.

Distributed gain measurements in Er-doped fibers with high resolution and accuracy using an optical frequency domain reflectometer

For critical erbium-doped fiber amplifier (EDFA) design, e.g., gain tilt optimization in WDM booster amplifiers, knowledge of the gain distribution within the active fiber can present a valuable information. Among the different techniques to evaluate the distributed gain in active fibers, the technique of optical frequency domain reflectometry seems most promising as it is a non-destructive measurement method well matched to the task due to its dynamic range, resolution, and range. Moreover, background light from ASE or residual pump light is strongly rejected due to the coherent detection scheme employed. Using different erbium-doped fibers with strongly varying doping levels and confinements, we demonstrate the excellent accuracy and reproducibility of the technique.