Effect of azithromycin and clarithromycin therapy on pharyngeal carriage of macrolide-resistant streptococci in healthy volunteers: a randomised, double-blind, placebo-controlled study

Effect of low-dose, long-term roxithromycin on airway inflammation and remodeling of stable noncystic fibrosis bronchiectasis

Background. Noncystic fibrosis bronchiectasis (NCFB) is characterized by airway expansion and recurrent acute exacerbations. Macrolide has been shown to exhibit anti-inflammatory effects in some chronic airway diseases. Objective. To assess the efficacy of roxithromycin on airway inflammation and remodeling in patients with NCFB under steady state. Methods. The study involved an open-label design in 52 eligible Chinese patients with NCFB, who were assigned to control (receiving no treatment) and roxithromycin (receiving 150 mg/day for 6 months) groups. At baseline and 6 months, the inflammatory markers such as interleukin- (IL-)8, neutrophil elastase (NE), matrix metalloproteinase- (MMP)9, hyaluronidase (HA), and type IV collagen in sputum were measured, along with the detection of dilated bronchus by throat computed tomography scan, and assessed the exacerbation. Results. Forty-three patients completed the study. The neutrophil in the sputum was decreased in roxithromycin group compared with control (P < 0.05). IL-8, NE, MMP-9, HA, and type IV collagen in sputum were also decreased in roxithromycin group compared with the control group (all P < 0.01). Airway thickness of dilated bronchus and exacerbation were reduced in roxithromycin group compared with the control (all P < 0.05). Conclusions. Roxithromycin can reduce airway inflammation and airway thickness of dilated bronchus in patients with NCFB.

Improvement of antibiotic prescription in outpatient care: a cluster-randomized intervention study using a sentinel surveillance network of physicians

OBJECTIVES

To assess the effectiveness of implementing guidelines, coupled with individual feedback, on antibiotic prescribing behaviour of primary care physicians in Switzerland.

METHODS

One hundred and forty general practices from a representative Swiss sentinel network of primary care physicians participated in this cluster-randomized prospective intervention study. The intervention consisted of providing guidelines on treatment of respiratory tract infections (RTIs) and uncomplicated lower urinary tract infections (UTIs), coupled with sustained, regular feedback on individual antibiotic prescription behaviour during 2 years. The main aims were: (i) to increase the percentage of prescriptions of penicillins for all RTIs treated with antibiotics; (ii) to increase the percentage of trimethoprim/sulfamethoxazole prescriptions for all uncomplicated lower UTIs treated with antibiotics; (iii) to decrease the percentage of quinolone prescriptions for all cases of exacerbated COPD (eCOPD) treated with antibiotics; and (iv) to decrease the proportion of sinusitis and other upper RTIs treated with antibiotics. The study was registered at ClinicalTrials.gov (NCT01358916).

RESULTS

While the percentage of antibiotics prescribed for sinusitis or other upper RTIs and the percentage of quinolones prescribed for eCOPD did not differ between the intervention group and the control group, there was a significant increase in the percentage of prescriptions of penicillins for all RTIs treated with antibiotics [57% versus 49%, OR=1.42 (95% CI 1.08-1.89), P=0.01] and in the percentage of trimethoprim/sulfamethoxazole prescriptions for all uncomplicated lower UTIs treated with antibiotics [35% versus 19%, OR=2.16 (95% CI 1.19-3.91), P=0.01] in the intervention group.

CONCLUSIONS

In our setting, implementing guidelines, coupled with sustained individual feedback, was not able to reduce the proportion of sinusitis and other upper RTIs treated with antibiotics, but increased the use of recommended antibiotics for RTIs and UTIs, as defined by the guidelines.

Long-term macrolide maintenance therapy in non-CF bronchiectasis: evidence and questions

Macrolide antibiotics have anti-inflammatory and immunomodulatory properties in addition to antibacterial activity. Until recently, only a small number of studies evaluating macrolides in patients with non-cystic fibrosis (CF) bronchiectasis had been published. These were open-label, uncontrolled, short-duration studies that included small numbers of patients. However, these studies suggested that macrolides can reduce exacerbation frequency, reduce sputum volume, and improve lung function in patients with non-CF bronchiectasis. Three recently published randomised, double-blind, placebo-controlled studies showed that macrolides (azithromycin or erythromycin) taken for between 6 and 12 months led to significant reductions in exacerbation rate and reduced the decline in lung function. In all studies, macrolides were generally well tolerated. The advantages of macrolide maintenance therapy need to be balanced against the risks, which include emergence of bacterial resistance, cardiotoxicity and ototoxicity. In addition, a key need is the consistent definition of endpoints for studies in non-CF bronchiectasis, particularly the definition of exacerbation, to allow systematic data analysis. Existing studies on the use of low-dose macrolides in non-CF bronchiectasis are encouraging, but further studies are needed to define the optimal agent, dose, duration for treatment, and the patients likely to benefit and long-term safety.

Development of a population pharmacokinetic model characterizing the tissue distribution of azithromycin in healthy subjects

Recent clinical trials indicate that the use of azithromycin is associated with the emergence of macrolide resistance. The objective of our study was to simultaneously characterize free target site concentrations and correlate them with the MIC90s of clinically relevant pathogens. Azithromycin (500 mg once daily [QD]) was administered orally to 6 healthy male volunteers for 3 days. The free concentrations in the interstitial space fluid (ISF) of muscle and subcutaneous fat tissue as well as the total concentrations in plasma and polymorphonuclear leukocytes (PMLs) were determined on days 1, 3, 5, and 10. All concentrations were modeled simultaneously in NONMEM 7.2 using a tissue distribution model that accounts for nonlinear protein binding and ionization state at physiological pH. The model performance and parameter estimates were evaluated via goodness-of-fit plots and nonparametric bootstrap analysis. The model we developed described the concentrations at all sampling sites reasonably well and showed that the overall pharmacokinetics of azithromycin is driven by the release of the drug from acidic cell/tissue compartments. The model-predicted unionized azithromycin (AZM) concentrations in the cytosol of PMLs (6.0 ± 1.2 ng/ml) were comparable to the measured ISF concentrations in the muscle (8.7 ± 2.9 ng/ml) and subcutis (4.1 ± 2.4 ng/ml) on day 10, whereas the total PML concentrations were >1,000-fold higher (14,217 ± 2,810 ng/ml). The total plasma and free ISF concentrations were insufficient to exceed the MIC90s of the skin pathogens at all times. Our results indicate that the slow release of azithromycin from low pH tissue/cell compartments is responsible for the long terminal half-life of the drug and thus the extended period of time during which free concentrations reside at subinhibitory concentrations.

Antibiotic dispensation by Lebanese pharmacists: a comparison of higher and lower socio-economic levels

INTRODUCTION

Indiscriminate use of antibiotics contributes to a global spread of antimicrobial resistance. Previous studies showed an excessive consumption of antibiotics purchased without medical prescription from community pharmacies, mainly in developing countries. There is a shortage of studies revealing the role of community pharmacists in the overuse of antibiotics. Our objective is to study the dispensing policy of non-medical prescription antibiotics in community pharmacies, assessing the possible influence of the socio-economic level of the area over this practice.

METHODS

A cross-sectional study was conducted between February and May 2011 among 100 pharmacists working in Beirut's pharmacies and its suburbs. Pharmacies were divided into 2 groups according to the socio-economic level of the population living in the pharmacy area. A self-administered questionnaire was filled by pharmacists.

RESULTS

Over-the-counter antibiotic availability existed in both higher and lower socio-economic areas: on the whole, 32% of antibiotics were dispensed without medical prescription, with higher frequency in lower socio-economic areas (p=0.003). Dispensing injectable antibiotics without medical prescription was significantly higher in lower socio-economic areas (p=0.021), as well as dispensing an association of 2 antibiotics without medical prescription (p=0.001). Pharmacists working in lower socio-economic areas recommended more frequent antibiotics to children and the elderly (p<0.001 and p=0.004, respectively).

CONCLUSION

Dispensing antibiotics without medical prescription in Beirut community pharmacies is a common practice, particularly in lower socioeconomic areas. This public health problem should be addressed at the social, educational, and legislative levels.

Is there a role for macrolides in severe asthma?

PURPOSE OF REVIEW

Severe asthma is a heterogeneous syndrome, encompassing several distinct clinical phenotypes. Different molecular and cellular pathways or endotypes determine the type of underlying airway inflammation in patients with severe asthma, which can be categorized as eosinophilic asthma (allergic and nonallergic) or noneosinophilic asthma (neutrophilic and paucigranulocytic). In this review, we discuss the potential role of macrolides in the treatment of severe asthma in adults.

RECENT FINDINGS

Maintenance treatment with low-dose macrolides such as erythromycin and azithromycin provides clinical benefit in several chronic neutrophilic airway diseases, including cystic fibrosis (CF), non-CF bronchiectasis and exacerbation-prone chronic obstructive pulmonary disease. Although several short-term studies of macrolides in mild-to-moderate asthma have failed to improve lung function, the AzIthromycin in Severe Asthma trial has demonstrated a significant reduction in the rate of exacerbations in patients with exacerbation-prone noneosinophilic severe asthma. As chronic macrolide use is associated with the risks of population antimicrobial resistance, this add-on treatment should be restricted to severe asthma patients at greatest unmet need despite optimal asthma management.

SUMMARY

Further clinical, translational and basic research is needed to better phenotype patients with severe asthma, to determine the risk-benefit ratio of macrolide maintenance treatment in neutrophilic severe asthma and to elucidate the principal mechanisms of action of macrolides.

Antibiotic stewardship in the intensive care unit

The rapid emergence and dissemination of antimicrobial-resistant microorganisms in ICUs worldwide constitute a problem of crisis dimensions. The root causes of this problem are multifactorial, but the core issues are clear. The emergence of antibiotic resistance is highly correlated with selective pressure resulting from inappropriate use of these drugs. Appropriate antibiotic stewardship in ICUs includes not only rapid identification and optimal treatment of bacterial infections in these critically ill patients, based on pharmacokinetic-pharmacodynamic characteristics, but also improving our ability to avoid administering unnecessary broad-spectrum antibiotics, shortening the duration of their administration, and reducing the numbers of patients receiving undue antibiotic therapy. Either we will be able to implement such a policy or we and our patients will face an uncontrollable surge of very difficult-to-treat pathogens.

Systemic antibiotic prescribing to paediatric outpatients in 5 European countries: a population-based cohort study

Background

To describe the utilisation of antibiotics in children and adolescents across 5 European countries based on the same drug utilisation measures and age groups. Special attention was given to age-group-specific distributions of antibiotic subgroups, since comparison in this regard between countries is lacking so far.

Methods

Outpatient paediatric prescriptions of systemic antibiotics during the years 2005-2008 were analysed using health care databases from the UK, the Netherlands, Denmark, Italy and Germany. Annual antibiotic prescription rates per 1,000 person years were estimated for each database and stratified by age (≤4, 5-9, 10-14, 15-18 years). Age-group-specific distributions of antibiotic subgroups were calculated for 2008.

Results

With 957 prescriptions per 1000 person years, the highest annual prescription rate in the year 2008 was found in the Italian region Emilia Romagna followed by Germany (561), the UK (555), Denmark (481) and the Netherlands (294). Seasonal peaks during winter months were most pronounced in countries with high utilisation. Age-group-specific use varied substantially between countries with regard to total prescribing and distributions of antibiotic subgroups. However, prescription rates were highest among children in the age group ≤4 years in all countries, predominantly due to high use of broad spectrum penicillins.

Conclusions

Strong increases of antibiotic prescriptions in winter months in high utilising countries most likely result from frequent antibiotic treatment of mostly viral infections. This and strong variations of overall and age-group-specific distributions of antibiotic subgroups across countries, suggests that antibiotics are inappropriately used to a large extent.

Previous antibiotic exposure and antimicrobial resistance in invasive pneumococcal disease: results from prospective surveillance

BACKGROUND

Estimating the risk of antibiotic resistance is important in selecting empiric antibiotics. We asked how the timing, number of courses, and duration of antibiotic therapy in the previous 3 months affected antibiotic resistance in isolates causing invasive pneumococcal disease (IPD).

METHODS

We conducted prospective surveillance for IPD in Toronto, Canada, from 2002 to 2011. Antimicrobial susceptibility was measured by broth microdilution. Clinical information, including prior antibiotic use, was collected by chart review and interview with patients and prescribers.

RESULTS

Clinical information and antimicrobial susceptibility were available for 4062 (90%) episodes; 1193 (29%) of episodes were associated with receipt of 1782 antibiotic courses in the prior 3 months. Selection for antibiotic resistance was class specific. Time elapsed since most recent antibiotic was inversely associated with resistance (cephalosporins: adjusted odds ratio [OR] per day, 0.98; 95% confidence interval [CI], .96-1.00; P = .02; macrolides: OR, 0.98; 95% CI, .96-.99; P = .005; penicillins: OR [log(days)], 0.62; 95% CI, .44-.89; P = .009; fluoroquinolones: profile penalized-likelihood OR [log(days)], 0.62; 95% CI, .39-1.04; P = .07). Risk of resistance after exposure declined most rapidly for fluoroquinolones and penicillins and reached baseline in 2-3 months. The decline in resistance was slowest for macrolides, and in particular for azithromycin. There was no significant association between duration of therapy and resistance for any antibiotic class. Too few patients received multiple courses of the same antibiotic class to assess the significance of repeat courses.

CONCLUSIONS

Time elapsed since last exposure to a class of antibiotics is the most important factor predicting antimicrobial resistance in pneumococci. The duration of effect is longer for macrolides than other classes.

Integrated DNA and RNA extraction and purification on an automated microfluidic cassette from bacterial and viral pathogens causing community-acquired lower respiratory tract infections

In this paper, we describe the development of an automated sample preparation procedure for etiological agents of community-acquired lower respiratory tract infections (CA-LRTI). The consecutive assay steps, including sample re-suspension, pre-treatment, lysis, nucleic acid purification, and concentration, were integrated into a microfluidic lab-on-a-chip (LOC) cassette that is operated hands-free by a demonstrator setup, providing fluidic and valve actuation. The performance of the assay was evaluated on viral and Gram-positive and Gram-negative bacterial broth cultures previously sampled using a nasopharyngeal swab. Sample preparation on the microfluidic cassette resulted in higher or similar concentrations of pure bacterial DNA or viral RNA compared to manual benchtop experiments. The miniaturization and integration of the complete sample preparation procedure, to extract purified nucleic acids from real samples of CA-LRTI pathogens to, and above, lab quality and efficiency, represent important steps towards its application in a point-of-care test (POCT) for rapid diagnosis of CA-LRTI.

Antimicrobial Stewardship Programs: Appropriate Measures and Metrics to Study their Impact

Antimicrobial stewardship is a new field that struggles to find the right balance between meaningful and useful metrics to study the impact of antimicrobial stewardship programs (ASPs). ASP metrics primarily measure antimicrobial use, although microbiological resistance and clinical outcomes are also important measures of the impact an ASP has on a hospital and its patient population. Antimicrobial measures looking at consumption are the most commonly used measures, and are focused on defined daily doses, days of therapy, and costs, usually standardized per 1,000 patient-days. Each measure provides slightly different information, with their own upsides and downfalls. Point prevalence measurement of antimicrobial use is an increasingly used approach to understanding consumption that does not entirely rely on sophisticated electronic information systems, and is also replicable. Appropriateness measures hold appeal and promise, but have not been developed to the degree that makes them useful and widely applicable. The primary reason why antimicrobial stewardship is necessary is the growth of antimicrobial resistance. Accordingly, antimicrobial resistance is an important metric of the impact of an ASP. The most common approach to measuring resistance for ASP purposes is to report rates of common or important community- or nosocomial-acquired antimicrobial-resistant organisms, such as methicillin-resistant Staphylococcus aureus and Clostridium difficile. Such an approach is dependent on detection methods, community rates of resistance, and co-interventions, and therefore may not be the most accurate or reflective measure of antimicrobial stewardship interventions. Development of an index to reflect the net burden of resistance holds theoretical promise, but has yet to be realized. Finally, programs must consider patient outcome measures. Mortality is the most objective and reliable method, but has several drawbacks. Disease- or organism-specific mortality, or cure, are increasingly used metrics.

Azithromycin maintenance treatment in patients with frequent exacerbations of chronic obstructive pulmonary disease (COLUMBUS): a randomised, double-blind, placebo-controlled trial

BACKGROUND

Macrolide resistance is an increasing problem; there is therefore debate about when to implement maintenance treatment with macrolides in patients with chronic obstructive pulmonary disease (COPD). We aimed to investigate whether patients with COPD who had received treatment for three or more exacerbations in the previous year would have a decrease in exacerbation rate when maintenance treatment with azithromycin was added to standard care.

METHODS

We did a randomised, double-blind, placebo-controlled, single-centre trial in The Netherlands between May 19, 2010, and June 18, 2013. Patients (≥18 years) with a diagnosis of COPD who had received treatment for three or more exacerbations in the previous year were randomly assigned, via a computer-generated randomisation sequence with permuted block sizes of ten, to receive 500 mg azithromycin or placebo three times a week for 12 months. Randomisation was stratified by use of long-term, low-dose prednisolone (≤10 mg daily). Patients and investigators were masked to group allocation. The primary endpoint was rate of exacerbations of COPD in the year of treatment. Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00985244.

FINDINGS

We randomly assigned 92 patients to the azithromycin group (n=47) or the placebo group (n=45), of whom 41 (87%) versus 36 (80%) completed the study. We recorded 84 exacerbations in patients in the azithromycin group compared with 129 in those in the placebo group. The unadjusted exacerbation rate per patient per year was 1·94 (95% CI 1·50-2·52) for the azithromycin group and 3·22 (2·62-3·97) for the placebo group. After adjustment, azithromycin resulted in a significant reduction in the exacerbation rate versus placebo (0·58, 95% CI 0·42-0·79; p=0·001). Three (6%) patients in the azithromycin group reported serious adverse events compared with five (11%) in the placebo group. During follow-up, the most common adverse event was diarrhoea in the azithromycin group (nine [19%] patients vs one [2%] in the placebo group; p=0·015).

INTERPRETATION

Maintenance treatment with azithromycin significantly decreased the exacerbation rate compared with placebo and should therefore be considered for use in patients with COPD who have the frequent exacerbator phenotype and are refractory to standard care.

FUNDING

SoLong Trust.

Antibiotic use in eastern Europe: a cross-national database study in coordination with the WHO Regional Office for Europe

BACKGROUND

There are no reliable data on antibiotic use in non-European Union (EU) southern and eastern European countries and newly independent states. We aimed to collect valid, representative, comparable data on systemic antimicrobial use in these non-EU countries of the WHO European region.

METHODS

Validated 2011 total national wholesale antibiotic-use data of six southern and eastern European countries and regions and seven newly independent states were analysed in accordance with the WHO anatomical therapeutic chemical (ATC)/defined daily doses (DDD) method and expressed in DDD/1000 inhabitants per day (DID).

FINDINGS

Total (outpatients and hospital care) antibiotic use ranged from 15·3 DID for Armenia to 42·3 DID for Turkey. Co-amoxiclav was mainly used in Georgia (42·9% of total antibiotic use) and Turkey (30·7%). Newly independent states used substantial quantities of ampicillin and amoxicillin (up to 55·9% of total antibiotic use in Azerbaijan). Montenegro and Serbia were the highest consumers of macrolides (15·8% and 19·5% of total antibiotic use, respectively), mainly azithromycin. Parenteral antibiotic treatment is common practice: 46·4% of total antibiotic use in Azerbaijan (mainly ampicillin; 5·3 DID) and 31·1% of total antibiotic use in Tajikistan (mainly ceftriaxone; 4·7 DID).

INTERPRETATION

This study provides publicly available total antibiotic-use data for 13 non-EU countries and areas of the WHO European region. These data will raise awareness of inappropriate antibiotic use and stimulate policy makers to develop action plans. The established surveillance system provides a method to develop quality indicators of antibiotic use and to assess the effect of policy and regulatory actions.

FUNDING

Netherlands Ministry of Health, Welfare, and Sport, and EU.

High prescription of antimicrobials in a rural district hospital in India

Background

The World Health Organization (WHO) recommends surveillance of antibiotic use as part of the strategy to fight against antimicrobial resistance. However, there is little information about the antibiotic consumption in developing countries, especially in rural areas.

Objective

The objective of this study was to describe the antimicrobial consumption in a rural hospital in India

Methods

The study was performed in a district hospital situated in Anantapur, Andhra Pradesh. In accordance with WHO recommendations, we used the defined daily dose (DDD) methodology to measure the antibiotic use during one year (from 1st August 2011 to 1st August 2012). The antibiotic use was measured using DDDs/100 admissions and DDDs/100 patient-days for inpatients, and DDDs/100 visits for outpatients.

Results

During the study period, there were 15,735 admissions and 250,611 outpatient visits. Antibiotics were prescribed for 86% of inpatients and 12.5% of outpatients. Outpatient prescriptions accounted for 2/3 of the overall antibiotic consumption. For inpatients, the total antibiotic use was 222 DDDs/ 100 patient-days, 693 DDDs/ 100 admissions and the mean number of antibiotics prescribed was 1.8. For outpatients, the total antibiotic use was 86 DDDs/ 100 outpatient visits and the mean number of antibiotics prescribed was 1.2. The most common antibiotics prescribed were aminopenicillins and 3rd generation cephalosporins for inpatients, and tetracyclines and quinolones for outpatients. In a sample of patients with diarrhoea or upper respiratory tract infections (URTI), the proportion of patients who received antibiotics was 84% (95% confidence interval [CI], 67-93) and 52% (95% CI, 43-62), respectively.

Conclusion

In this rural setting, the use of antimicrobials was extremely high, even in conditions with a predominantly viral aetiology such as diarrhoea or URTI.

[Long-term macrolide treatment in adult chronic bronchial diseases: benefits and limits]

Decreased frequency of pulmonary exacerbations, mainly related to immunomodulatory effects of macrolide antibiotics, has been demonstrated in bronchiectasis and chronic obstructive pulmonary diseases (COPD). Due to its tolerance, azithromycin is the antibiotic of choice for maintenance therapy at the dose of 250 mg per day or 500 mg × 3 per week (for body weight >55 kg). Maintenance therapy with macrolide could be proposed in selected patients with bronchiectasis or COPD with more than 3 acute exacerbations in the previous year or decreased lung function despite compliance with optimum treatment. The risk of sudden cardiac death with azithromycin is rare and controversial. It should be avoided in patients with a high baseline risk of cardiovascular disease, QT>450 msec, pulse rate>100 bpm and potential drug interactions, particularly those known to cause QT prolongation. It is recommended to search for hearing deficit (audiometry) and sputum culture positive for mycobacteria. Patients must also be aware that it can rapidly lead to macrolide resistance in commensal or pathogenic flora. Follow-up evaluation every 3 month can be proposed with medical history (hearing deficit) and electrocardiography. After one year, the treatment should be stopped in the absence of reduction in the frequency of exacerbations.

Measuring trends of outpatient antibiotic use in Europe: jointly modelling longitudinal data in defined daily doses and packages

OBJECTIVES

To complement analyses of the linear trend and seasonal fluctuation of European outpatient antibiotic use expressed in defined daily doses (DDD) by analyses of data in packages, to assess the agreement between both measures and to study changes in the number of DDD per package over time.

METHODS

Data on outpatient antibiotic use, aggregated at the level of the active substance (WHO version 2011) were collected from 2000 to 2007 for 31 countries and expressed in DDD and packages per 1000 inhabitants per day (DID and PID, respectively). Data expressed in DID and PID were analysed separately using non-linear mixed models while the agreement between these measurements was analysed through a joint non-linear mixed model. The change in DDD per package over time was studied with a linear mixed model.

RESULTS

Total outpatient antibiotic and penicillin use in Europe and their seasonal fluctuation significantly increased in DID, but not in PID. The use of combinations of penicillins significantly increased in DID and in PID. Broad-spectrum penicillin use did not increase significantly in DID and decreased significantly in PID. For all but one subgroup, country-specific deviations moved in the same direction whether measured in DID or PID. The correlations are not perfect. The DDD per package increased significantly over time for all but one subgroup.

CONCLUSIONS

Outpatient antibiotic use in Europe shows contrasting trends, depending on whether DID or PID is used as the measure. The increase of the DDD per package corroborates the recommendation to adopt PID to monitor outpatient antibiotic use in Europe.

Azithromycin: mechanisms of action and their relevance for clinical applications

Azithromycin is a macrolide antibiotic which inhibits bacterial protein synthesis, quorum-sensing and reduces the formation of biofilm. Accumulating effectively in cells, particularly phagocytes, it is delivered in high concentrations to sites of infection, as reflected in rapid plasma clearance and extensive tissue distribution. Azithromycin is indicated for respiratory, urogenital, dermal and other bacterial infections, and exerts immunomodulatory effects in chronic inflammatory disorders, including diffuse panbronchiolitis, post-transplant bronchiolitis and rosacea. Modulation of host responses facilitates its long-term therapeutic benefit in cystic fibrosis, non-cystic fibrosis bronchiectasis, exacerbations of chronic obstructive pulmonary disease (COPD) and non-eosinophilic asthma. Initial, stimulatory effects of azithromycin on immune and epithelial cells, involving interactions with phospholipids and Erk1/2, are followed by later modulation of transcription factors AP-1, NFκB, inflammatory cytokine and mucin release. Delayed inhibitory effects on cell function and high lysosomal accumulation accompany disruption of protein and intracellular lipid transport, regulation of surface receptor expression, of macrophage phenotype and autophagy. These later changes underlie many immunomodulatory effects of azithromycin, contributing to resolution of acute infections and reduction of exacerbations in chronic airway diseases. A sub-group of post-transplant bronchiolitis patients appears to be sensitive to azithromycin, as may be patients with severe sepsis. Other promising indications include chronic prostatitis and periodontitis, but weak activity in malaria is unlikely to prove crucial. Long-term administration of azithromycin must be balanced against the potential for increased bacterial resistance. Azithromycin has a very good record of safety, but recent reports indicate rare cases of cardiac torsades des pointes in patients at risk.

Trends and seasonal variation in outpatient antibiotic prescription rates in the United States, 2006 to 2010

Antibiotic-resistant bacteria are an increasing threat to the effectiveness of antibiotics. The majority of antibiotics are prescribed in primary care settings for upper respiratory tract infections. The purpose of this study was to describe seasonal trends in outpatient antibiotic prescriptions (Rx) in the United States over a 5-year period. This study was a retrospective, cross-sectional observation of systemic antibiotic prescriptions in the outpatient setting from 2006 to 2010. Winter months were defined as the first and fourth quarters of the calendar year. Antibiotic prescribing rates were calculated (prescriptions/1,000 population) using annual U.S. Census Bureau population data. Over 1.34 billion antibiotic prescriptions were dispensed over the 5-year period. The antibiotic prescription (Rx) rate decreased from 892 Rx/1,000 population in 2006 to 867 Rx/1,000 population in 2010. Penicillins and macrolides were the primary antibiotic classes prescribed, but penicillin prescribing decreased while macrolide prescribing increased over the study period. Overall, antibiotic prescriptions were 24.5% higher in winter months than in the summer, with the largest difference (28.8%) in 2008 and the smallest (20.4%) in 2010. This seasonality was consistently drug class dependent, driven by 75% and 100% increases in penicillin and macrolide prescriptions, respectively, in the winter months. The mean outpatient antibiotic prescription rate decreased in the United States from 2006 to 2010. More antibiotic prescribing, predominately driven by the macrolide and penicillin classes, in the outpatient setting was observed in the winter months. Understanding annual variability in antibiotic use can assist with designing interventions to improve the judicious use of antibiotics.

Clinical utility of PCR for common viruses in acute respiratory illness

BACKGROUND

Acute respiratory illness (ARI) accounts for a large proportion of all visits to pediatric health facilities. Quantitative real-time polymerase chain reaction (qPCR) analyses allow sensitive detection of viral nucleic acids, but it is not clear to what extent specific viruses contribute to disease because many viruses have been detected in asymptomatic children. Better understanding of how to interpret viral findings is important to reduce unnecessary use of antibiotics.

OBJECTIVE

To compare viral qPCR findings from children with ARI versus asymptomatic control subjects.

METHODS

Nasopharyngeal aspirates were collected from children aged ≤5 years with ARI and from individually matched, asymptomatic, population-based control subjects during a noninfluenza season. Samples were analyzed by using qPCR for 16 viruses.

RESULTS

Respiratory viruses were detected in 72.3% of the case patients (n = 151) and 35.4% of the control subjects (n = 74) (P = .001). Rhinovirus was the most common finding in both case patients and control subjects (47.9% and 21.5%, respectively), with a population-attributable proportion of 0.39 (95% confidence interval: 0.01 to 0.62). Metapneumovirus, parainfluenza viruses, and respiratory syncytial virus were highly overrepresented in case patients. Bocavirus was associated with ARI even after adjustment for coinfections with other viruses and was associated with severe disease. Enterovirus and coronavirus were equally common in case patients and control subjects.

CONCLUSIONS

qPCR detection of respiratory syncytial virus, metapneumovirus, or parainfluenza viruses in children with ARI is likely to be causative of disease; detection of several other respiratory viruses must be interpreted with caution due to high detection rates in asymptomatic children.

Expectations for consultations and antibiotics for respiratory tract infection in primary care: the RTI clinical iceberg

BACKGROUND

Respiratory tract infection (RTI) is the commonest indication for community antibiotic prescriptions. Prescribing is rising and is influenced by patients' consulting behaviour and beliefs.

AIM

To build up a profile of the 'RTI clinical iceberg' by exploring how the general public manage RTI, visit GPs and why.

DESIGN AND SETTING

Two-phase qualitative and quantitative study in England.

METHOD

Qualitative interviews with 17 participants with acute RTI visiting pharmacies in England, and face-to-face questionnaire survey of 1767 adults ≥15 years in households in England during January 2011.

RESULTS

Qualitative interviews: interviewees with RTI visited GPs if they considered their symptoms were prolonged, or severe enough to cause pain, or interfered with daily activities or sleep. Questionnaire: 58% reported having had an RTI in the previous 6 months, and 19.7% (95% CI = 16.8 to 22.9%) of these contacted or visited their GP surgery for this, most commonly because 'the symptoms were severe'; or 'after several days the symptoms hadn't improved'; 10.3% of those experiencing an RTI (or 53.1% of those contacting their GP about it) expected an antibiotic prescription. Responders were more likely to believe antibiotics would be effective for a cough with green rather than clear phlegm. Perceptions of side effects of antibiotics did not influence expectations for antibiotics. Almost all who reported asking for an antibiotic were prescribed one, but 25% did not finish them.

CONCLUSION

One-fifth of those with an RTI contact their GP and most who ask for antibiotics are prescribed them. A better public understanding about the lack of benefit of antibiotics for most RTIs and addressing concerns about illness duration and severity, could reduce GP consultations and antibiotic prescriptions for RTI.

Effect of introducing procalcitonin on antimicrobial therapy duration in patients with sepsis and/or pneumonia in the intensive care unit

BACKGROUND

Utilizing procalcitonin (PCT) levels to limit antimicrobial overuse would be beneficial from a humanistic and economic perspective.

OBJECTIVE

To assess whether introducing PCT at a teaching hospital reduced antimicrobial exposure in critically ill patients.

METHODS

Patients wereadmitted to the intensive care unit (ICU) for >72 hours with sepsis and/or pneumonia. PCT levels were drawn on admission to the ICU or with new suspected infection, with at least 1 PCT level being drawn at least 48 hours later. Patients were matched in a 1:1 fashion to historical patients on age, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, gender, and primary diagnosis. The primary outcome was duration of initial antimicrobial exposure defined as days from initiation of antimicrobial therapy to the intentional discontinuation of therapy by the physician. Secondary end points included length of stay, readmission to the hospital, and relapse of infection.

RESULTS

There were 50 patients in the PCT group and 50 patients in the historical group. The initial duration of antimicrobials was 10 (±4.9) days compared with 13.3 (±7.2), which was statistically significant (P = .0238). The duration of stay in the hospital (13.5 compared with 17.8 days; P = .0299), readmission to the hospital (9 compared with 17; P = .055), and relapse of infection (3 compared with 11; P = .02) were seen less in the PCT group compared with controls.

CONCLUSION

Introducing PCT levels resulted in a shorter duration of initial antimicrobial therapy and was not associated with adverse treatment outcomes.

Impact of pneumococcal conjugate vaccines on microbial epidemiology and clinical outcomes of acute otitis media

Acute otitis media (AOM) is the leading bacterial infection in childhood and the main reason for antibiotic prescriptions in children. The success of pneumococcal conjugate vaccines (PCVs) in reducing invasive pneumococcal disease has been demonstrated in many studies. Because Streptococcus pneumoniae is one of the two main bacterial species implicated in AOM, the incidence and characteristics of AOM might also be modified by PCVs. Pre-licensure controlled studies showed that the effect was modest. However, after PCV7 implementation, the impact on the AOM burden appeared to be more marked, despite the fact that serotype replacement in the nasopharynx was almost complete. Most data on the impact of PCVs on nasopharyngeal flora have been drawn from studies with PCV7. No difference was observed with PCV10 compared with PCV7 concerning S. pneumoniae and Haemophilus influenza carriage. For PCV13 compared with PCV7, additional reduction of carriage of serotypes 1, 6A, 7F, 6C, 19A, and 19F was observed, but for the other serotypes, the two PCVs seemed to have the same effect.

Appropriate international measures for outpatient antibiotic prescribing and consumption: recommendations from a national data comparison of different measures

OBJECTIVES

Many European countries have engaged in awareness campaigns to decrease outpatient antibiotic use and several measures have been proposed, e.g. the number of defined daily doses (DDDs) or packages per 1000 inhabitants per day, producing conflicting findings. Therefore, we set out to explore what measure is most appropriate.

METHODS

Outpatient data on each dispensed and reimbursed medicinal package in Belgium between 2002 and 2009 were aggregated at the level of the active substance in accordance with the Anatomical Therapeutic Chemical classification and expressed as the numbers of DDDs (WHO, version 2010), packages, treatments and insured individuals per 1000 inhabitants, insured individuals and patient contacts, per day, and in July-June years. Using these measures, time trends of outpatient antibiotic use were compared and explored in detail.

RESULTS

Expressed per 1000 inhabitants per day, outpatient antibiotic use increased between 2002-03 and 2008-09 in DDDs, whereas in packages, treatments and insured individuals it decreased. The same was true for use expressed per 1000 insured individuals or when allowing for the decreasing number of patient contacts. Increasing numbers of DDDs per package (more items per package and higher doses per unit for amoxicillin and co-amoxiclav) explain these discrepancies.

CONCLUSIONS

The number of packages is a more appropriate measure than the number of DDDs when assessing outpatient antibiotic use over time and the impact of awareness campaigns in countries dispensing 'complete packages'. We recommended the use of different complementary measures or caution when interpreting trends based only on DDDs.

Antibiotic Prescribing in Primary Care and Antimicrobial Resistance in Patients Admitted to Hospital with Urinary Tract Infection: A Controlled Observational Pilot Study

There is growing evidence that primary care prescribed antibiotics lead to antibiotic resistance in bacteria causing minor infections or being carried by asymptomatic adults, but little research to date has investigated links between primary care prescribed antibiotics and resistance among more serious infections requiring hospital care. Knowledge of these effects is likely to have a major influence on public expectations for, and primary care use of, antibiotics. This study aimed to assess the feasibility of recruiting symptomatic adult patients admitted to hospital with urinary infections and to link primary and secondary data information to investigate the relationship between primary care prescribed antibiotics and antimicrobial resistance in these patients. A microbiology database search of in patients who had submitted a urine sample identified 740 patients who were potentially eligible to take part in the study. Of these, 262 patients did not meet the eligibility criteria, mainly due to use of a urinary catheter (40%). Two-hundred and forty three patients could not be recruited as the nurse was unable to visit the patients prior to discharge, as they were too unwell. Eighty patients provided complete information. Results indicate that there is evidence that prior antibiotic use is associated with resistant infections in hospital patients. A fully powered study, conducted using routinely collected data is proposed to fully clarify the precision of the association.

The increasing application of multiplex nucleic acid detection tests to the diagnosis of syndromic infections

On 14 January 2013, the US Food and Drug Administration (FDA) announced permission for a multiplex nucleic acid test, the xTAG® Gastrointestinal Pathogen Panel (GPP) (Luminex Corporation, USA), which simultaneously detects 11 common viral, bacterial and parasitic causes of infectious gastroenteritis, to be marketed in the USA. This announcement reflects the current move towards the development and commercialization of detection technologies based on nucleic acid amplification techniques for diagnosis of syndromic infections. We discuss the limitations and advantages of nucleic acid amplification techniques and the recent advances in Conformité Européene - in-vitro diagnostic (CE-IVD)-approved multiplex real-time PCR kits for the simultaneous detection of multiple targets within the clinical diagnostics market.

Associations between host characteristics and antimicrobial resistance ofSalmonellaTyphimurium

A collection ofSalmonellaTyphimurium isolates obtained from sporadic salmonellosis cases in humans from Lower Saxony, Germany between June 2008 and May 2010 was used to perform an exploratory risk-factor analysis on antimicrobial resistance (AMR) using comprehensive host information on sociodemographic attributes, medical history, food habits and animal contact. Multivariate resistance profiles of minimum inhibitory concentrations for 13 antimicrobial agents were analysed using a non-parametric approach with multifactorial models adjusted for phage types. Statistically significant associations were observed for consumption of antimicrobial agents, region type and three factors on egg-purchasing behaviour, indicating that besides antimicrobial use the proximity to other community members, health consciousness and other lifestyle-related attributes may play a role in the dissemination of resistances. Furthermore, a statistically significant increase in AMR from the first study year to the second year was observed.

Epidemiological interpretation of studies examining the effect of antibiotic usage on resistance

Bacterial resistance to antibiotics is a growing clinical problem and public health threat. Antibiotic use is a known risk factor for the emergence of antibiotic resistance, but demonstrating the causal link between antibiotic use and resistance is challenging. This review describes different study designs for assessing the association between antibiotic use and resistance and discusses strengths and limitations of each. Approaches to measuring antibiotic use and antibiotic resistance are presented. Important methodological issues such as confounding, establishing temporality, and control group selection are examined.

Quality of antibiotic prescription during office hours and out-of-hours in Flemish primary care, using European quality indicators

BACKGROUND

European disease-specific antibiotic prescribing quality indicators (APQI) were proposed for seven acute indications (bronchitis, upper respiratory infection, cystitis, tonsillitis, sinusitis, otitis media and pneumonia): (a) the percentage of patients prescribed an antibiotic; (b) the percentage of patients receiving the guideline recommended antibiotic; (c) the percentage of patients receiving quinolones.

OBJECTIVES

To assess the feasibility of calculating values for these 21 APQI using primary care databases; and to assess the quality of antibiotic prescribing in office hours and out-of-hours general practice.

METHODS

Data was extracted from a morbidity registration network ( http://www.intego.be ) and the out-of-hours service centre in Flanders. Within both databases diagnoses are labelled using the revised second edition of International Classification of Primary Care (ICPC-2-R) and antibiotic prescriptions using Anatomical Therapeutic Chemical (ATC) classification.

RESULTS

Both databases allow calculation of APQI values and results are similar. Only for cystitis was the percentage of patients prescribed an antibiotic within the proposed acceptable range. For all indications, the percentage of recommended antibiotics was below the proposed acceptable range (80-100%). The percentage of quinolones was within the proposed acceptable range (0-5%) for otitis media, upper respiratory infection and tonsillitis.

CONCLUSION

Primary care databases can produce APQI values. These values revealed huge opportunities to improve the quality of antibiotic prescribing in office hours and out-of-hours Flemish general practice, especially the prescription of recommended antibiotics.

Antibiotic prescribing for adults in ambulatory care in the USA, 2007-09

OBJECTIVES

To determine patterns of ambulatory antibiotic prescribing in US adults, including the use of broad-spectrum versus narrow-spectrum agents, to provide a description of the diagnoses for which antibiotics are prescribed and to identify patient and physician factors associated with broad-spectrum antibiotic prescribing.

METHODS

We used data for patients aged ≥ 18 years from the National Ambulatory and National Hospital Ambulatory Medical Care Surveys (2007-09). These are nationally representative surveys of patient visits to offices, hospital outpatient departments and emergency departments (EDs) in the USA, collectively referred to as ambulatory visits. We determined the types of antibiotics prescribed, including the use of broad-spectrum versus narrow-spectrum antibiotics, and examined prescribing patterns by diagnoses. We used multivariable logistic regression to identify factors associated with broad-spectrum antibiotic prescribing.

RESULTS

Antibiotics were prescribed during 101 million (95% CI: 91-111 million) ambulatory visits annually, representing 10% of all visits. Broad-spectrum agents were prescribed during 61% of visits in which antibiotics were prescribed. The most commonly prescribed antibiotics were quinolones (25% of antibiotics), macrolides (20%) and aminopenicillins (12%). Antibiotics were most commonly prescribed for respiratory conditions (41% of antibiotics), skin/mucosal conditions (18%) and urinary tract infections (9%). In multivariable analysis, among patients prescribed antibiotics, broad-spectrum agents were more likely to be prescribed than narrow-spectrum antibiotics for respiratory infections for which antibiotics are rarely indicated (e.g. bronchitis), during visits to EDs and for patients ≥ 60 years.

CONCLUSIONS

Broad-spectrum agents constitute the majority of antibiotics in ambulatory care. More than 25% of prescriptions are for conditions for which antibiotics are rarely indicated. Antibiotic stewardship interventions targeting respiratory and non-respiratory conditions are needed in ambulatory care.

[Appropriateness of antibiotic prescribing in a primary care area: a cross-sectional study]

OBJECTIVE

To assess the profile of patients receiving antibiotics and the appropriateness of these prescriptions for the clinical conditions.

METHODS

DESIGN

Cross-sectional study of prescription-indication.

SETTING

A primary health care area in Andalusia.

SUBJECTS

Patients assigned to primary care centres. Patients with antibiotic prescriptions during 2009 were selected by simple random sampling (confidence level: 95%, accuracy: 5%). Primary endpoint: appropriateness of antibiotics prescribing to recommendations included in local guidelines. Data were obtained through the billing computerised prescriptions system and medical histories.

RESULTS

Twenty-five per cent of the population area received antibiotics during 2009. The 1,266 patient samples showed the following characteristics: 57.9% were women, with a mean age of 41 (±1) years. There were 39.3% pensioners. The percentage of appropriate antibiotic prescriptions was 19.9%, with no difference due to gender. Statistically significant differences were related to age, being those over 65 years the group of patients with the highest percentage of inappropriateness. The main reasons for inappropriateness were: no recording of the infectious process (44.5%), a wrong treatment duration (15.5%), and the use of an inadequate antibiotic (11.5%).

CONCLUSION

There is a high level of inappropriateness in antibiotic prescribing in primary care. The high level of under-recording of diagnoses, mainly in elderly patients, followed by the use of wrong schedules, and the wrong type of antibiotics were the main reasons of inappropriateness.

A systematic review of antibiotic utilization in China

OBJECTIVES

Reliable data about antibiotic utilization in the large pharmaceutical market of the world's most populous country, the People's Republic of China, are in short supply. Although many primary studies have investigated the use of antibiotics in China, most of the relevant studies were published in the Chinese language. This systematic review aims to summarize reported percentages of outpatient encounters resulting in the prescription of antibiotics in China.

METHODS

We systematically searched and reviewed studies of antibiotic prescribing patterns in China, published in Chinese or English between 2000 and August 2012. The study quality was assessed and the overall percentage of outpatient encounters resulting in the prescription of antibiotics was calculated using random-effects meta-analysis. Subgroup analyses were conducted to investigate heterogeneity across studies.

RESULTS

We included 57 eligible studies (with a total of 556 ,435 outpatient encounters). The overall percentage of outpatients prescribed antibiotics was 50.3% (95% CI: 47.4%-53.1%). Of the outpatients prescribed antibiotics, 74.0% (95% CI: 71.3%-76.6%) were prescribed one antibiotic, 23.3% (95% CI: 21.1%-25.7%) were prescribed two antibiotics and 2.0% (95% CI: 1.3%-2.8%) were prescribed three or more antibiotics. The proportion of antibiotic utilization differed greatly across hospital levels and geographical regions and fluctuated over time.

CONCLUSIONS

The percentage use of antibiotics is high in China. The excessive use of antibiotics is particularly more problematic in lower-level hospitals and in less developed western China. The implementation and impact of the national efforts to control the excessive use of antibiotics should be appropriately evaluated.

Systemic antibiotic use among children and adolescents in Germany: a population-based study

The aim of the study was to comprehensively describe antibiotic use among children and young adolescents in Germany. Outpatient prescriptions of systemic antibiotics to children (<15 years) were analysed using data from four German statutory health insurances for the years 2004 to 2006. Annual prevalence of antibiotic prescriptions was determined using the average number of insured children during the respective year as reference population. Annual antibiotic prescription rates were calculated per 1,000 person years. Both figures were stratified by age (0-4, 5-9 and 10-14 years) and sex. Frequent indications for prescribing were analysed. Annual prevalence of antibiotic prescriptions rose from 35.68 % [95 % confidence intervals (CI), 35.62-35.75] in 2004 to 37.79 % [95 % CI, 37.72-37.86] in 2006. Prescription rates slightly increased by 6.01 % from 668.54 [95 % CI, 667.34-669.72] antibiotic prescriptions per 1,000 person years in 2004 to 708.71 [95 % CI, 707.47-709.95] in 2006. In 2006, prescriptions of broad-spectrum penicillins (25.09 %), second-generation cephalosporins (18.11 %) and narrow-spectrum penicillins (16.45 %) were most frequent. The most common indication for antibiotic prescribing was tonsillitis followed by bronchitis, otitis media, acute upper respiratory infections and scarlet fever.

CONCLUSION

In contrast to other northern European countries, paediatric prescription rates are high in Germany. This and the frequent prescribing of broad spectrum agents for the treatment of mostly viral self-limiting conditions indicate limited adherence to evidence-based practice guidelines in antibiotic prescribing in the German outpatient setting.

MRSA nasal colonization in children: prevalence meta-analysis, review of risk factors and molecular genetics

BACKGROUND

We report a meta-analysis of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization prevalence in children and a review of the risk factors as well as molecular genetic characterization.

METHODS

All relevant studies reporting prevalence data on MRSA nasal colonization in children published between January 2000 and August 2010 were retrieved from the MEDLINE database and analyzed.

RESULTS

After screening 544 studies, 50 studies were included. We obtained an estimate of MRSA prevalence of 2.7% (95% confidence interval [CI]: 2.2-3.1); of 5.2% (95% CI: 3.1-7.3) in children with underlying conditions and of 2.3% (95% CI: 1.8-2.7) in healthy children; 5.4% (95% CI: 3.1-7.7) in children recruited in hospitals and 3% (95% CI: 2.4-3.6) in children recruited in the community. Staphylococcal cassette chromosome mec type IV is the most diffused cassette globally.

CONCLUSION

The hospital remains the environment where the microorganism circulates most. Children with underlying conditions could act as vectors of microorganisms between the hospital and the community. MRSA prevention strategies should be tailored to each specific institution, taking into account the nosocomial prevalence of MRSA nasal colonization and infections, and the prevalence of nasal colonization in the community that refers to the specific health care center.

Risks of population antimicrobial resistance associated with chronic macrolide use for inflammatory airway diseases

Macrolide antibiotics have established efficacy in the management of cystic fibrosis and diffuse panbronchiolitis-uncommon lung diseases with substantial morbidity and the potential for rapid progression to death. Emerging evidence suggests benefits of maintenance macrolide treatment in more indolent respiratory diseases including chronic obstructive pulmonary disease and non-cystic fibrosis bronchiectasis. In view of the greater patient population affected by these disorders (and potential for macrolide use to spread to disorders such as chronic cough), widespread use of macrolides, particularly azithromycin, has the potential to substantially influence antimicrobial resistance rates of a range of respiratory microbes. In this Personal View, I explore theories around population (rather than patient) macrolide resistance, appraise evidence linking macrolide use with development of resistance, and highlight the risks posed by injudicious broadening of their use, particularly of azithromycin. These risks are weighed against the potential benefits of macrolides in less aggressive inflammatory airway disorders. A far-sighted approach to maintenance macrolide use in non-cystic fibrosis inflammatory airway diseases is needed, which minimises risks of adversely affecting community macrolide resistance: combining preferential use of erythromycin and restriction of macrolide use to those patients at greatest risk represents an appropriately cautious management approach.

Mass distribution of azithromycin for trachoma control is associated with increased risk of azithromycin-resistant Streptococcus pneumoniae carriage in young children 6 months after treatment

BACKGROUND

Emerging evidence suggests that the mass distribution of azithromycin for trachoma control (MDA) may increase circulation of macrolide resistance in bacteria associated with severe pediatric infections in treated communities.

METHODS

We examined the effect of MDA on nasopharyngeal carriage of antibiotic-resistant Streptococcus pneumoniae among 1015 young children living in rural Tanzania. MDA with a single dose of oral azithromycin was provided in 4 of 8 communities where trachoma prevalence was ≥10%. Isolates were tested for susceptibility to azithromycin (AZM) and commonly used antibiotics by disk diffusion and Etest. We calculated the proportion of antibiotic-resistant S. pneumoniae carriage at baseline and again 1, 3, and 6 months after treatment, and at comparable intervals in the untreated villages.

RESULTS

The proportion of AZM-resistant isolates was similar between groups at baseline (MDA: 35.8% vs non-MDA: 35.4%), however, this proportion was greater in the MDA group in all subsequent surveys. At 6 months, the percentage of AZM-resistant isolates was significantly higher in the MDA group (81.9% vs 46.9%, P < .001). The odds of AZM-resistant carriage was 5-fold greater in the MDA group (odds ratio, 4.95 [95% confidence interval, 3.23-7.61]). The proportion of isolates clinically resistant to AZM (minimum inhibitory concentration ≥16 µg/mL) was also significantly greater in the MDA group at 6 months (35.3% vs 12.4%, P < .006).

CONCLUSIONS

Mass distribution of a single dose of oral azithromycin for trachoma was associated with increased circulation of macrolide-resistant S. pneumoniae carriage among young children in the 6 months following treatment. It is crucial that changes in antibiotic resistance patterns and their clinical significance in the treatment of severe pediatric infections be assessed in future MDA trials.

Blood, tissue, and intracellular concentrations of azithromycin during and after end of therapy

Although azithromycin is extensively used in the treatment of respiratory tract infections as well as skin and skin-related infections, pharmacokinetics of azithromycin in extracellular space fluid of soft tissues, i.e., one of its therapeutic target sites, are not yet fully elucidated. In this study, azithromycin concentration-time profiles in extracellular space of muscle and subcutaneous adipose tissue, but also in plasma and white blood cells, were determined at days 1 and 3 of treatment as well as 2 and 7 days after the end of treatment. Of all compartments, azithromycin concentrations were highest in white blood cells, attesting for intracellular accumulation. However, azithromycin concentrations in both soft tissues were markedly lower than in plasma both during and after treatment. Calculation of the area under the concentration-time curve from 0 to 24 h (AUC(0-24))/MIC(90) ratios for selected pathogens suggests that azithromycin concentrations measured in the present study are subinhibitory at all time points in both soft tissues and at the large majority of observed time points in plasma. Hence, it might be speculated that azithromycin's clinical efficacy relies not only on elevated intracellular concentrations but possibly also on its known pleotropic effects, including immunomodulation and influence on bacterial virulence factors. However, prolonged subinhibitory azithromycin concentrations at the target site, as observed in the present study, might favor the emergence of bacterial resistance and should therefore be considered with concern. In conclusion, this study has added important information to the pharmacokinetic profile of the widely used antibiotic drug azithromycin and evidentiates the need for further research on its potential for induction of bacterial resistance.

Update on the management of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a common disorder characterized by mucosal inflammation of the nose and paranasal sinuses with sinonasal symptoms persisting for greater than 12 weeks. The etiology of CRS is incompletely understood. Current understanding supports inflammation, rather than infection, as the dominant etiologic factor. CRS significantly impacts patients' quality of life and health care expenditure. There is no standard management of CRS. Treatment strategies differ based on divergent etiologies of the various CRS subclasses. Both systemic and topical agents are used. These interventions differ in CRS with nasal polyposis (CRSwNP), CRS without nasal polyposis (CRSsNP) and specific situations such as allergic fungal rhinosinusitis or aspirin-exacerbated respiratory disease. Antibiotics are the most commonly prescribed medication for CRS, but their role in management is not strongly supported by high-level studies. This paper provides a succinct review of the evidence supporting or refuting common therapeutic agents in the management of CRS. Novel and emerging strategies will also be discussed.

Antimicrobial drug use and macrolide-resistant Streptococcus pyogenes, Belgium

In Belgium, decreasing macrolide, lincosamide, streptogramins B, and tetracycline use during 1997–2007 correlated significantly with decreasing macrolide-resistant Streptococcus pyogenes during 1999–2009. Maintaining drug use below a critical threshold corresponded with low-level macrolide-resistant S. pyogenes and an increased number of erm(A)-harboring emm77 S. pyogenes with low fitness costs.

Antimicrobial stewardship: a review of prospective audit and feedback systems and an objective evaluation of outcomes

Antimicrobial stewardship is an emerging field currently defined by a series of strategies and interventions aimed toward improving appropriate prescription of antibiotics in humans in all healthcare settings. The ultimate goal is the preservation of current and future antibiotics against the threat of antimicrobial resistance, although improving patient safety and reducing healthcare costs are important concurrent aims. Prospective audit and feedback interventions are probably the most widely practiced of all antimicrobial stewardship strategies. Although labor-intensive, they are more easily accepted by physicians compared with formulary restriction and preauthorization strategies and have a higher potential for educational opportunities. Objective evaluation of antimicrobial stewardship is critical for determining the success of such programs. Nonetheless, there is controversy over which outcomes to measure and there is a pressing need for novel study designs that can objectively assess antimicrobial stewardship interventions despite the limitations inherent in the structure of most such programs.

Antimicrobial agent exposure and the emergence and spread of resistant microorganisms: issues associated with study design

Antibiotics are essential agents that have greatly reduced human mortality due to infectious diseases. Their use, and sometimes overuse, have increased over the past several decades in humans, veterinary medicine and agriculture. However, the emergence of resistant pathogens is becoming an increasing problem that could result in the re-emergence of infectious diseases. Antibiotic prescription in human medicine plays a key role in this phenomenon. Under selection pressure, resistance can emerge in the commensal flora of treated individuals and disseminate to others. However, even if the effects of antimicrobial use on resistance is intuitively accepted, scientific rationales are required to convince physicians, legislators and public opinion to adopt appropriate behaviours and policies. With this review, we aim to provide an overview of different epidemiological study designs that are used to study the relationship between antibiotic use and the emergence and spread of resistance, as well as highlight their main strengths and weaknesses.