The effect of changes in the consumption of macrolide antibiotics on erythromycin resistance in group A streptococci in Finland. Finnish Study Group for Antimicrobial Resistance

The fitness costs of antibiotic resistance mutations

Antibiotic resistance is increasing in pathogenic microbial populations and is thus a major threat to public health. The fate of a resistance mutation in pathogen populations is determined in part by its fitness. Mutations that suffer little or no fitness cost are more likely to persist in the absence of antibiotic treatment. In this review, we performed a meta-analysis to investigate the fitness costs associated with single mutational events that confer resistance. Generally, these mutations were costly, although several drug classes and species of bacteria on average did not show a cost. Further investigations into the rate and fitness values of compensatory mutations that alleviate the costs of resistance will help us to better understand both the emergence and management of antibiotic resistance in clinical settings.

Antibiotic prescribing by telephone in primary care

OBJECTIVES

Little is known about the contribution of telephone-based prescribing on overall antibiotic utilization. The objective of this study was to determine the extent and characteristics of telephone-based antibiotic prescribing in teaching and non-teaching primary care practices.

METHODS

This retrospective cohort study included all patients (n = 114 610) cared for by teaching and non-teaching internal medicine, pediatrics, family practice, and obstetrics/gynecology practices (n = 19) affiliated with a large US healthcare system during 2006-2010 and using a common electronic medical record. Rates and types of antibiotics prescribed by teaching and non-teaching practices via telephone contact and office visit were compared among the overall cohort. All telephone-related prescriptions during 2008 underwent chart review to determine indications for antibiotic prescribing.

RESULTS

Overall, 28.9 antibiotic prescriptions were issued per 100 patient-years, with 63 418 total antibiotic prescriptions and 7876 (12.4%) generated after telephone contact. Telephone-based prescribing increased steadily from 2.2 to 4.2 per 100 patient-years during the study period. Both telephone-based and office-based antibiotic prescribing were higher in non-teaching practices. Of 1790 antibiotics prescribed by telephone during 2008, the majority were for urinary tract infection (28.3%), sinusitis (20.1%), and unspecified upper respiratory infection (URI, 15.0%).

CONCLUSIONS

Overall, one in every eight antibiotics was prescribed via telephone encounter. These data highlight the need to include the impact of this practice in analysis of outcomes associated with outpatient antibiotic prescribing and to incorporate telephonic prescribing into guidelines facilitating appropriate antibiotic use.

Costs of antibiotic resistance - separating trait effects and selective effects

Antibiotic resistance can impair bacterial growth or competitive ability in the absence of antibiotics, frequently referred to as a ‘cost’ of resistance. Theory and experiments emphasize the importance of such effects for the distribution of resistance in pathogenic populations. However, recent work shows that costs of resistance are highly variable depending on environmental factors such as nutrient supply and population structure, as well as genetic factors including the mechanism of resistance and genetic background. Here, we suggest that such variation can be better understood by distinguishing between the effects of resistance mechanisms on individual traits such as growth rate or yield (‘trait effects’) and effects on genotype frequencies over time (‘selective effects’). We first give a brief overview of the biological basis of costs of resistance and how trait effects may translate to selective effects in different environmental conditions. We then review empirical evidence of genetic and environmental variation of both types of effects and how such variation may be understood by combining molecular microbiological information with concepts from evolution and ecology. Ultimately, disentangling different types of costs may permit the identification of interventions that maximize the cost of resistance and therefore accelerate its decline.

Understanding Antibiotic Use in Minya District, Egypt: Physician and Pharmacist Prescribing and the Factors Influencing Their Practices

Overuse of antibiotics has contributed to the emergence of antibiotic-resistant bacteria globally. In Egypt, patients can purchase antibiotics without a prescription, and we hypothesized frequent inappropriate antibiotic prescribing and dispensing. We interviewed physicians (n = 236) and pharmacists (n = 483) and conducted focus groups in Minya, Egypt, to assess attitudes and practices regarding antibiotic prescribing for outpatient acute respiratory infections (ARI). Antibiotics were reportedly prescribed most of the time or sometimes for colds by 150 (64%) physicians and 326 (81%) pharmacists. The most commonly prescribed antibiotics were β-lactams. Macrolides were the second most commonly prescribed for colds and sinusitis. The prescription of more than one antibiotic to treat pneumonia was reported by 85% of physicians. Most respondents thought antibiotic overuse contributes to resistance and reported “patient self-medication” as the biggest driver of overuse. Fifty physicians (21%) reported that they had prescribed antibiotics unnecessarily, citing patient over-the-counter access as the reason. Physicians <40 years of age and those who treat adults were more likely to prescribe antibiotics for colds. Overall, we found a high rate of unwarranted outpatient antibiotic prescribing and dispensing for ARIs. Patient access to OTC antibiotics contributes to over-prescribing. National guidelines for ARI treatment, provider education and national policy requiring a physician’s prescription for antibiotics may improve appropriate antibiotic use in Egypt.

Selection and evolution of resistance to antimicrobial drugs

The overuse and misuse of antibiotics over many years has selected a high frequency of resistance among medically important bacterial pathogens. The evolution of resistance is complex, frequently involving multiple genetic alterations that minimize biological fitness costs and/or increase the resistance level. Resistance is selected at very low drug concentrations, such as found widely distributed in the environment, and this selects for resistant mutants with a high fitness. Once resistance with high fitness is established in a community it is very difficult to reduce its frequency. Addressing the problem of resistance is essential if we are to ensure a future where we can continue to enjoy effective medical control of bacterial infections. This will require several actions including the discovery and development of novel antibiotics, the creation of a continuous pipeline of drug discovery, and the implementation of effective global antibiotic stewardship to reduce the misuse of antibiotics and their release into the environment.

A qualitative study of pharmacists' perceptions of, and recommendations for improvement of antibiotic use in Qatar

BACKGROUND

Use of antibiotics has been correlated with increasing rates of resistance. Pharmacists are ideally positioned as front line health care providers to limit indiscriminate antibiotic use and promote the safe and effective administration of these medications.

OBJECTIVE

The aim of this project was to assess pharmacists' opinions relating to antibiotic utilization in the community setting.

SETTING

Doha, Qatar.

METHOD

Community and primary care pharmacists were invited to participate in one of three focus groups or a semi-structured interview at Qatar University or at their site of employment. A total of 22 community and primary care pharmacists participated in this study. Interviews were facilitated using a focus group guide, were recorded, and later transcribed. Transcripts were reviewed for recurring themes and coded using Nvivo software for qualitative research.

MAIN OUTCOME MEASURE

Pharmacists' perceptions.

RESULTS

Five major themes emerged from a series of focus groups and interviews. Themes which recurred across interview groups included: misconceptions and inappropriate practices by patients and healthcare providers, currently implemented strategies, perceived barriers, ways to overcome perceived barriers, and targets for improvement of antibiotic use in Qatar. The greatest need, as identified by pharmacists in this study was increased knowledge of the general population about appropriate antibiotic use through various educational interventions.

CONCLUSION

Pharmacists report a number of misconceptions and inappropriate practices relating to antibiotic use in Qatar by patients and healthcare providers. Education to improve knowledge of appropriate antibiotic use is needed. Despite recognition of these issues, barriers are preventing pharmacists from implementing strategies to improve antibiotic use in Qatar.

Reversibility of antibiotic resistance

Although theoretically attractive, the reversibility of resistance has proven difficult in practice, even though antibiotic resistance mechanisms induce a fitness cost to the bacterium. Associated resistance to other antibiotics and compensatory mutations seem to ameliorate the effect of antibiotic interventions in the community. In this paper the current understanding of the concepts of reversibility of antibiotic resistance and the interventions performed in hospitals and in the community are reviewed.

Disease manifestations and pathogenic mechanisms of Group A Streptococcus

Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.

Audit and Feedback-Focused approach to Evidence-based Care in Treating patients with pneumonia in hospital (AFFECT Study)

BACKGROUND

Pneumonia is the eighth leading cause of death in Canada. Use of guideline-concordant therapy tempers the development of resistance, decreases health care costs, and reduces morbidity and mortality.

OBJECTIVES

The purpose of this study was to optimize the treatment of patients with pneumonia under hospitalist care by focusing on best practice and local antibiogram data. The objectives were to collaborate with a hospitalist representative to optimize in-hospital treatment of patients with community-acquired, hospital-acquired, and health care-associated pneumonia; to complete a baseline audit to determine the proportion of antibiotic orders adhering to the strategy; to present the strategy and baseline audit findings to the hospitalists; to perform a post-intervention audit, with comparison to baseline, and to present results to the hospitalists; to expedite de-escalation to a narrower-spectrum antibiotic; to expedite parenteral-to-oral step-down therapy and promote appropriate duration of therapy; and to determine if a pneumonia scoring system was used.

METHODS

An audit and feedback intervention focusing on pre- and post-intervention retrospective chart audits was completed. Review of pneumonia guidelines and the local antibiogram assisted in identifying the study strategy. A presentation to the hospitalists outlined antimicrobial stewardship principles and described the findings of the baseline audit. Pre- and post-intervention audit results were compared.

RESULTS

Local best-practice treatment algorithms were developed for community-acquired pneumonia and for hospital-acquired and health care-associated pneumonia. The pre-intervention audit covered the period December 2011 to January 2012, with subsequent education and audit results presented to the hospitalists in November 2012. The post-intervention audit covered the period December 2012 to January 2013. Adherence to the treatment algorithms increased from 10% (2/21) in the pre-intervention audit to 38% (5/13) in the post-intervention audit. There was a trend to reduced duration of therapy in the post-intervention group.

CONCLUSION

An audit and feedback intervention related to hospitalists' prescribing for pneumonia increased adherence to local best practice.

Long-term effects of an educational seminar on antibiotic prescribing by GPs: a randomised controlled trial

BACKGROUND

High levels of outpatient antibiotic use remain observed in many European countries. Several studies have shown a strong relationship between antibiotic use and bacterial resistance.

AIM

To assess the long-term effect of a standardised educational seminar on antibiotic prescriptions by GPs.

DESIGN AND SETTING

Randomised controlled trial of 171 GPs (of 203 initially randomised) in France.

METHOD

GPs in the control group (n = 99) received no antibiotic prescription recommendation. Intervention group GPs (n = 72) attended an interactive seminar presenting evidence-based guidelines on antibiotic prescription for respiratory infections. The proportion of prescriptions containing an antibiotic in each group and related costs were compared to the baseline up to 30 months following the intervention. Data were obtained from the National Health Insurance System database.

RESULTS

In the intervention group, 4-6 months after the intervention, there was a significant decrease in the proportion of prescriptions containing an antibiotic from 15.2 ± 5.4% to 12.3 ± 5.8% (-2.8% [95% CI = -3.8 to -1.9], P<0.001). By contrast, an increase was observed in controls from 15.3 ± 6.0 to 16.4 ± 6.7% (+1.1% [95% CI = +0.4 to +1.8], P<0.01), resulting in a between-group difference of 3.93% ([95% CI = 2.75 to 5.11], P<0.001). The between-group difference was maintained 30 months after intervention (1.99% [95% CI = 0.56 to 3.42], P<0.01). Persistence of the intervention effect over the entire study period was confirmed in a hierarchical multivariate analysis.

CONCLUSION

This randomised trial shows that a standardised and interactive educational seminar results in a long-term reduction in antibiotic prescribing and could justify a large-scale implementation of this intervention.

Experimental evolution as an efficient tool to dissect adaptive paths to antibiotic resistance

Antibiotic treatments increasingly fail due to rapid dissemination of drug resistance. Comparative genomics of clinical isolates highlights the role of de novo adaptive mutations and horizontal gene transfer (HGT) in the acquisition of resistance. Yet it cannot fully describe the selective pressures and evolutionary trajectories that yielded today's problematic strains. Experimental evolution offers a compelling addition to such studies because the combination of replicated experiments under tightly controlled conditions with genomics of intermediate time points allows real-time reconstruction of evolutionary trajectories. Recent studies thus established causal links between antibiotic deployment therapies and the course and timing of mutations, the cost of resistance and the likelihood of compensating mutations. They particularly underscored the importance of long-term effects. Similar investigations incorporating horizontal gene transfer (HGT) are wanting, likely because of difficulties associated with its integration into experiments. In this review, we describe current advances in experimental evolution of antibiotic resistance and reflect on ways to incorporate horizontal gene transfer into the approach. We contend it provides a powerful tool for systematic and highly controlled dissection of evolutionary paths to antibiotic resistance that needs to be taken into account for the development of sustainable anti-bacterial treatment strategies.

Trimethoprim prescription and subsequent resistance in childhood urinary infection: multilevel modelling analysis

BACKGROUND

Antibiotic resistance is a growing concern and antibiotic usage the main contributing factor, but there are few studies examining antibiotic use and resistance in children.

AIM

To investigate the association between previous trimethoprim prescribing and resistance in urinary Escherichia coli (E. coli) isolates in children.

DESIGN AND SETTING

Retrospective, population cohort study in Tayside, Scotland.

METHOD

Multilevel modelling of linked microbiology and dispensed prescribing data for 1373 ≤16-year-olds with E. coli urinary isolates in 2004-2009, examining the association between prior trimethoprim prescription and subsequent trimethoprim resistance in people with urinary E. coli isolates.

RESULTS

Trimethoprim resistance was common (26.6%, 95% confidence interval [CI] = 24.6 to 28.6). Previous trimethoprim prescription was associated with subsequent culture of trimethoprim-resistant E. coli, with more recent prescription being more strongly associated with resistance. After adjusting for the number of previous E. coli isolates and sample year, trimethoprim prescribing in the previous 84 days remained significantly associated with culturing trimethoprim-resistant E. coli (adjusted OR 4.71, 95% CI = 1.83 to 12.16 for the previous 15-28 days versus never prescribed; adjusted OR 3.16, 95% CI = 1.63 to 6.13 for the previous 29-84 days); however, associations were not statistically significant for longer periods since prior exposure.

CONCLUSION

Trimethoprim prescription has implications for future resistance in individual children, as well as at population level. Clinicians must ensure appropriateness of treatment choice and duration, and alternative antibiotics should be considered for childhood urinary tract infections if trimethoprim has been prescribed in the preceding 3 months.

Use of antibiotics among non-medical students in a Nigerian university

BACKGROUND

Antibiotic misuse is a major contributory factor to treatment failure, antibiotic resistance and high healthcare costs.

OBJECTIVES

To evaluate level of self-reported antibiotic misuse among non-medical undergraduate students of a Nigerian university.

METHODS

Respondents' knowledge of antibiotics and disposal system for left-over antibiotics were explored using a structured questionnaire. Data were summarized with descriptive statistics. Chi square was used to evaluate relationship between specific categorical variables and respondents' opinions with p<0.05.

RESULTS

More than half the respondents obtained their antibiotics through doctor's prescriptions (273; 68.3%). The study revealed gross antibiotic misuse with majority, (298;74.5%) either by keeping left-over antibiotics for future use or throwing it away with refuse. Respondents (289; 72.3%) sometimes forgot to take the antibiotics. Financial constraints (73; 18.3%), long duration of treatment (70; 17.5%), side effects experienced (60;15.0%), polypharmacy (56;14.0%), tablet size (45;11.3%), and perceived low level of confidence in the prescriber (11; 2.8%) were major reasons for non-adherence. Course of study of respondents had no significant effect on respondents' knowledge or adherence (p>0.05).

CONCLUSION

Misuse of antibiotics among non-medical undergraduate students in a Nigerian university setting is pervasive suggesting an urgent need for enlightenment on rational use and disposal of antibiotics.

Preliminary assessment of photoactivated antimicrobial collagen on bioburden in a murine pressure ulcer model

OBJECTIVE AND BACKGROUND DATA

Overcoming bacterial antibiotic resistance requires alternative strategies. The ability of photoactivated collagen-embedded flavins (PCF) to reduce bioburden in infected pressure ulcers was investigated.

DESIGN AND METHODS

Two pressure ulcers were created on the dorsum of female BALB/C mice (n=40, 35 g) maintaining a 5 mm skin bridge between lesions. Ulcers and surrounding skin were covered with Tegaderm™ and inoculated with 0.1 mL of 1 × 10(5) colony-forming units (CFU)/mL methicillin-resistant Staphylococcus aureus (MRSA). Fluid was permitted to reabsorb for 10 min. In experiment 1, one wound from each animal was treated using PCF and photoradiation (PCF+R, n=12) or photoradiation alone (R, n=11). Composite dressing-treated wounds received 1 × 1 cm PCF discs. Overlying Tegaderm was excised, and PCF was placed over the wound and again covered with Tegaderm. Wounds were irradiated at 455 ± 5 nm (350 mW, 1 cm spot diameter, 15 min) using a diode laser 10 min after placement. Controls received no PCF or photoradiation (C, n=12). Animals were euthanized 24 h post-therapy. Quantitative bacterial counts (CFU/g tissue) were determined. In experiment 2, composite dressing-treated wounds were irradiated at 455 ± 5 nm (350 mW, 1 cm spot diameter, 15 min) using a diode laser 10 min after daily PCF placement (0, 1, 2, or 3 treatments, n=8/group). Controls received no treatment. Wounds were cultured daily. Animals were euthanized on day 7 post-infection. Quantitative bacterial counts were determined.

RESULTS

PCF+R significantly reduced bacterial counts at 24 h (experiment 1, p<0.0001; experiment 2, p<0.05). The bacterial counts in rats receiving photoradiation alone were no different from those of untreated controls (experiment 1, p=0.24). PCF+R produced a 2-3 log reduction in bacterial counts (experiment 2, p<0.001). Antibacterial effects increased with number of treatments, and persisted for several days post-therapy (p<0.002).

CONCLUSIONS

PCF+R inhibited bacterial growth in this model. This effect increased with successive treatments, persisting several days post-therapy. Further studies to optimize this treatment modality are warranted.

Improving antibiotic prescribing in acute respiratory tract infections: cluster randomised trial from Norwegian general practice (prescription peer academic detailing (Rx-PAD) study)

OBJECTIVE

To assess the effects of a multifaceted educational intervention in Norwegian general practice aiming to reduce antibiotic prescription rates for acute respiratory tract infections and to reduce the use of broad spectrum antibiotics.

DESIGN

Cluster randomised controlled study.

SETTING

Existing continuing medical education groups were recruited and randomised to intervention or control.

PARTICIPANTS

79 groups, comprising 382 general practitioners, completed the interventions and data extractions.

INTERVENTIONS

The intervention groups had two visits by peer academic detailers, the first presenting the national clinical guidelines for antibiotic use and recent research evidence on acute respiratory tract infections, the second based on feedback reports on each general practitioner's antibiotic prescribing profile from the preceding year. Regional one day seminars were arranged as a supplement. The control arm received a different intervention targeting prescribing practice for older patients.

MAIN OUTCOME MEASURES

Prescription rates and proportion of non-penicillin V antibiotics prescribed at the group level before and after the intervention, compared with corresponding data from the controls.

RESULTS

In an adjusted, multilevel model, the effect of the intervention on the 39 intervention groups (183 general practitioners) was a reduction (odds ratio 0.72, 95% confidence interval 0.61 to 0.84) in prescribing of antibiotics for acute respiratory tract infections compared with the controls (40 continuing medical education groups with 199 general practitioners). A corresponding reduction was seen in the odds (0.64, 0.49 to 0.82) for prescribing a non-penicillin V antibiotic when an antibiotic was issued. Prescriptions per 1000 listed patients increased from 80.3 to 84.6 in the intervention arm and from 80.9 to 89.0 in the control arm, but this reflects a greater incidence of infections (particularly pneumonia) that needed treating in the intervention arm.

CONCLUSIONS

The intervention led to improved antibiotic prescribing for respiratory tract infections in a representative sample of Norwegian general practitioners, and the courses were feasible to the general practitioners.

TRIAL REGISTRATION

Clinical trials NCT00272155.

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.

In VitroInduction of Resistance by Tissue Concentrations of Azithromycin, Clarithromycin, Cefixime and Amoxicillin/Clavulanate in Clinical Isolates ofStreptococcus pyogenes

This study evaluated the effects of exposure to serum, tonsils and breakpoint drug concentrations of clarithromycin, azithromycin, cefixime and amoxicillin/clavulanate on Streptococcus pyogenes susceptibility. Frequency of mutation and development of resistance after ten passages on antibiotic gradient plates, followed by ten passages without antibiotic, were determined. Phenotypes of macrolide-resistant strains grown at the end of multi-step selection were also determined. Azithromycin induced a surge of resistant strains more rapidly and frequently than clarithromycin, particularly at tonsils concentrations. With amoxicillin/clavulanate no strains showed minimum inhibitory concentrations (MICs) higher than the susceptibility breakpoint. Mutational frequencies were higher for azithromycin, at serum and breakpoint drug concentrations, than for the other drugs. Most of the macrolide resistant strains showed an MLS(B) phenotype. In conclusion, the ability to prevent the occurrence of resistance in clinical isolates of S. pyogenes was similar for amoxicillin/clavulanate and clarithromycin followed by cefixime > azithromycin when tonsil drug concentrations were considered, and greater for amoxicillin/clavulanate followed by clarithromycin > cefixime> azithromycin, at breakpoint and serum concentrations.

Successful reduction of hospital-acquired methicillin-resistant Staphylococcus aureus in a urology ward: a 10-year study

BACKGROUND

To eradicate hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) using a stepwise infection control strategy that includes an avoidance of antimicrobial prophylaxis (AMP) based on surgical wound classification and an improvement in operative procedures in gasless single-port urologic surgery.

METHODS

The study was conducted at an 801-bed university hospital. Since 2001, in the urology ward, we have introduced the stepwise infection control strategy. In 2007, surveillance cultures for MRSA in all urological patients were commenced. The annual incidence of MRSA was calculated as a total number of newly identified MRSA cases per 1,000 patient days. Trend analysis was performed using a Poisson regression.

RESULTS

Over the study period, 139,866 patients, including 10,201 urology patients, were admitted to our hospital. Of these patients, 3,719 patients, including 134 ones in the urology ward, were diagnosed with MRSA throughout the entire hospital. Although the incidence of MRSA increased throughout the entire hospital (p = 0.002), it decreased significantly in the urology ward (p < 0.0001). Of the 134 cases, 45 (33.6%) were classified as "imported," and 89 (66.4%) as "acquired." In the urology ward, the incidence of acquired MRSA decreased significantly over time (p < 0.0001), whereas the incidence of imported MRSA did not change over time (p = 0.66). A significant decrease (p < 0.0001) in the incidence of clinically significant MRSA infection over time was found.

CONCLUSIONS

Stepwise infection control strategy that includes a reduction or avoidance of antimicrobial prophylaxis in minimally invasive surgery can contribute to a reduction in hospital-acquired MRSA.

TRIAL REGISTRATION

Current study has approved by the institutional ethical review board (No.1141).

Habitual use of push and pull plastic bottle caps is more prevalent among children with recurrent acute otitis media

OBJECTIVE

The use of a pacifier has been reported to be a causative factor of recurrent acute otitis media (RAOM) because the negative pressure which is generated during sucking may cause a negative intra-tympanic pressure and favour the reflux of nasopharyngeal secretions into the Eustachian tube. Push and pull (P&P) plastic bottle caps, recently marketed in Italy, might also induce negative nasopharyngeal pressure. This study was aimed to investigate if there is a difference in the prevalence of habitual use of P&P plastic bottle caps among children with a positive history of RAOM and healthy controls.

METHODS

A telephonic interview was performed in order to retrospectively evaluate the prevalence of habitual use of P&P plastic bottle cap among children with a history of RAOM and healthy controls, comparable to the former for environmental risk factors for RAOM.

RESULTS

Data were obtained from 57 Caucasian patients (males=36/57; 63.2%) with a median age of 59 (range=21-90) months, including 28 children with a history of RAOM and 29 healthy controls. Habitual use of P&P plastic bottle cap was significantly (p=0.047) more frequent in children with a history of RAOM (14/28; 50.0%) than in control group (7/29; 24.2%). Multivariate logistic regression analysis adjusted for age confirmed a significant association (p<0.01; Pseudo R(2)=0.2) between the use of P&P plastic bottle cap and a positive history of RAOM (adjusted OR=4.0; range=1.1-15.0).

CONCLUSIONS

Our preliminary data show a significantly increased prevalence of P&P plastic cap bottle habitual users among children with a history or RAOM and support the need for larger studies to confirm the role of using P&P bottles as risk factor of RAOM and to identify the age groups at higher risk.

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.

Chronic rhinosinusitis and emerging treatment options

This review describes the epidemiology and various treatments in chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). Evidence for short-term use of systemic corticosteroids has been shown to be favorable in CRSwNP, but still limited in CRSsNP. Topical corticosteroids improve symptom scores in both CRS subgroups. The role of microbes in CRS is still controversial. Culture-directed antibiotics are recommended for CRSsNP with exacerbation. Long-term use of low dosage antibiotics is recommended for CRSsNP for their anti-inflammatory effects. Other emerging treatment options are also discussed.

Rationale, design and organization of the delayed antibiotic prescription (DAP) trial: a randomized controlled trial of the efficacy and safety of delayed antibiotic prescribing strategies in the non-complicated acute respiratory tract infections in general practice

Background

Respiratory tract infections are an important burden in primary care and it’s known that they are usually self-limited and that antibiotics only alter its course slightly. This together with the alarming increase of bacterial resistance due to increased use of antimicrobials calls for a need to consider strategies to reduce their use. One of these strategies is the delayed prescription of antibiotics.

Methods

Multicentric, parallel, randomised controlled trial comparing four antibiotic prescribing strategies in acute non-complicated respiratory tract infections. We will include acute pharyngitis, rhinosinusitis, acute bronchitis and acute exacerbation of chronic bronchitis or chronic obstructive pulmonary disease (mild to moderate). The therapeutic strategies compared are: immediate antibiotic treatment, no antibiotic treatment, and two delayed antibiotic prescribing (DAP) strategies with structured advice to use a course of antibiotics in case of worsening of symptoms or not improving (prescription given to patient or prescription left at the reception of the primary care centre 3 days after the first medical visit).

Discussion

Delayed antibiotic prescription has been widely used in Anglo-Saxon countries, however, in Southern Europe there has been little research about this topic. The DAP trial wil evaluate two different delayed strategies in Spain for the main respiratory infections in primary care.

Trial registration

This trial is registered with ClinicalTrials.gov, number http://NCT01363531.

Antimicrobial resistance: action to combat the rising microbial challenges

Antimicrobial therapy transformed medical practice from a merely diagnosis-focused approach 80 years ago to a treatment-focused approach, saving millions of lives in the years to follow. Today, numerous medical advances made possible by effective antibiotics are being threatened by the relentlessly rising rates of bacteria resistant to all currently available antibiotics. This phenomenon is a consequence of antibiotic misuse, which exerts undue selective pressure on micro-organisms, combined with defective infection control practices that accelerate their spread. Its impact on societies worldwide is immense, resulting in loss of human life and money. An alarming pattern of resistance involving multidrug-resistant and sometimes pandrug-resistant Gram-negative bacteria is currently emerging. In response to the global public health threat posed by antimicrobial resistance (AMR), a number of national and international actions and initiatives have been developed in recent years to address this issue. Although the optimally effective and cost-effective strategy to reduce AMR is not known, a multifaceted approach is most likely to be successful. It should include actions aiming at optimising antibiotic use, strengthening surveillance and infection control, and improving healthcare worker and public education with regard to antibiotics. Research efforts to bring new effective antibiotics to patients need to be fostered in order to negate the consequences of the current lack of antimicrobial therapy options. A holistic view of AMR as well as intersectoral collaboration between human and veterinary medicine is required to best address the problem.

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.

Application of basic pharmacology and dispensing practice of antibiotics in accredited drug-dispensing outlets in Tanzania

BACKGROUND

Provision of pharmaceutical services in accredited drug-dispensing outlets (ADDOs) in Tanzania has not been reported. This study compared the antibiotics dispensing practice between ADDOs and part II shops, or duka la dawa baridi (DLDBs), in Tanzania.

METHODOLOGY

This was a cross-sectional study that was conducted in ADDOs and DLDBs. A simulated client method for data collection was used, and a total of 85 ADDOs, located in Mvomero, Kilombero, and Morogoro rural districts, were compared with 60 DLDBs located in Kibaha district. The research assistants posed as simulated clients and requested to buy antibiotics from ADDOs and DLDBs after presenting a case scenario or disease condition. Among the diseases presented were those requiring antibiotics and those usually managed only by oral rehydration salt or analgesics. The simulated clients wanted to know the antibiotics that were available at the shop. The posed questions set a convincing ground to the dispenser either to dispense the antibiotic directly, request a prescription, or refer the patient to a health facility. Proportions were used to summarize categorical variables between ADDOs and DLDBs, and the chi-square test was used to test for statistical difference between the two drug-outlet types in terms of antibiotic-dispensing practice.

RESULTS

As many as 40% of trained ADDO dispensers no longer worked at the ADDO shops, so some of the shops employed untrained staff. A larger proportion of ADDOs than DLDBs dispensed antibiotics without prescriptions (P = 0.004). The overall results indicate that there was no difference between the two types of shops in terms of adhering to regulations for dispensing antibiotics. However, in some circumstances, eg, antibiotic sale without prescription and no referral made, for complicated cases, ADDOs performed worse than DLDBs. As many as 30% of DLDBs and 35% of ADDOs dispensed incomplete doses of antibiotics. In both ADDOs and DLDBs, fortified procaine penicillin powder was dispensed as topical application for injuries.

CONCLUSION

There was no statistical difference between ADDOs and DLDBs in the violation of dispensing practice and both ADDOs and DLDBs expressed poor knowledge of the basic pharmacology of antibiotics.

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.

Minimal inhibitory and mutant prevention concentrations of azithromycin, clarithromycin and erythromycin for clinical isolates of Streptococcus pneumoniae

BACKGROUND

Previous work showed a higher prevalence of macrolide/azalide resistance in provinces of Canada where azithromycin was the major treatment for Streptococcus pneumoniae as compared with regions where clarithromycin was the dominant treatment. These data provided a way to test the mutant selection window hypothesis, which predicts that the serum drug concentration (AUC(24)) relative to the mutant prevention concentration (MPC) would be higher for clarithromycin than for azithromycin.

METHODS

The MIC and MPC were determined for 191 penicillin/macrolide-susceptible clinical isolates of S. pneumoniae with azithromycin, clarithromycin and erythromycin using agar plate assays.

RESULTS

The MIC(50/90) (mg/L) and MPC(50/90) (mg/L), respectively, were as follows: azithromycin 0.13/0.25 and 1/4; clarithromycin 0.031/0.063 and 0.13/0.5; erythromycin 0.063/0.13 and 0.25/2. We calculated from published pharmacokinetic values that the AUC(24)/MPC(90) for azithromycin was 0.85; for clarithromycin it was 96, and for erythromycin base and estolate it was 4 and 10, respectively. Thus the AUC(24)/MPC(90) was about 50 times higher for clarithromycin than for azithromycin.

CONCLUSIONS

The elevated prevalence of azithromycin resistance may derive in part from a low value of AUC(24)/MPC(90) and/or time above MPC, since previous work indicates that the number of prescriptions per person was similar in the geographical regions examined.

Decline in macrolide-resistant Streptococcus pyogenes isolates from French children

We studied the macrolide resistance and serotypes of 585 group A streptococcus (GAS) isolates collected from French children with pharyngitis. Nineteen isolates (3.2%) were erythromycin-resistant and harbored the following resistance genes: 31.6% mef(A), 15.8% erm(A), and 52.6% erm(B). The 19 isolates included 7 different emm types (4, 1, 11, 2, 28, 12, and 77) and 7 corresponding multilocus sequence types. The current fall in macrolide consumption has led to a very low rate of GAS macrolide resistance.

Risk factors for multidrug-resistant invasive pneumococcal disease in South Africa, a setting with high HIV prevalence, in the prevaccine era from 2003 to 2008

The emergence of multidrug-resistant (MDR) Streptococcus pneumoniae complicates disease management. We aimed to determine risk factors associated with MDR invasive pneumococcal disease (IPD) in South Africa and evaluate the potential for vaccination to reduce disease burden. IPD data collected by laboratory-based surveillance from 2003 through 2008 were analyzed. Multidrug resistance was defined as nonsusceptibility to any three or more different antibiotic classes. Risk factors for multidrug resistance were evaluated using multivariable logistic regression. Of 20,100 cases of IPD identified, 3,708 (18%) had MDR isolates, with the proportion increasing from 16% (461/2,891) to 20% (648/3,326) (P < 0.001) over the study period. Serotypes included in the 13-valent pneumococcal conjugate vaccine (PCV13) accounted for 94% of MDR strains. Significant risk factors for MDR IPD included PCV13 (1,486/6,407; odds ratio [OR] of 6.3; 95% confidence interval [CI] of 5.0 to 7.9) and pediatric (3,382/9,980; OR of 12.8; 95% CI of 10.6 to 15.4) serotypes, age of <5 (802/3,110; OR of 2.0; 95% CI of 1.8 to 2.3) or ≥65 (39/239; OR of 1.5; 95% CI of 1.0 to 2.2) years versus age of 15 to 64 years, HIV infection (975/4,636; OR of 1.5; 95% CI of 1.2 to 1.8), previous antibiotic use (242/803; OR of 1.7; 95% CI of 1.4 to 2.1), previous hospital admissions (579/2,450; OR of 1.2; 95% CI of 1.03 to 1.4), urban location (883/4,375; OR of 2.0; 95% CI of 1.1 to 3.5), and tuberculosis treatment (246/1,021; OR of 1.2; 95% CI of 1.03 to 1.5). MDR IPD prevalence increased over the study period. The effect of many of the MDR risk factors could be reduced by more judicious use of antibiotics. Because PCV13 serotypes account for most MDR infections, pneumococcal vaccination may reduce the prevalence of multidrug resistance.

Overview of strategies for overcoming the challenge of antimicrobial resistance

The discovery of penicillin undoubtedly transformed the management of life-threatening bacterial infections. However, a less comfortable aspect of the antibiotic revolution was that within 10 years, over 80% of patients with acute bronchitis were receiving antibiotics without any evidence of clinical benefit. Antibiotic use inevitably causes collateral damage to the normal human flora and increases the risk of infection with antibiotic-resistant bacteria and Clostridium difficile. The twin aims of antibiotic stewardship are first to ensure effective treatment for patients with bacterial infection and second to provide convincing evidence and information to educate and support professionals and patients to reduce unnecessary use and minimize collateral damage. We review evidence of progress with these aims in Europe and nationally in Scotland.

Clarithromycin Extended-Release Tablet

Clarithromycin is an orally active, advanced-generation macrolide that has been reformulated as an extended-release tablet (Biaxin) XL Filmtab allowing convenient once-daily administration. The reformulation is intended to improve patient compliance and the tolerability of the drug. Although maximum plasma clarithromycin concentrations are lower and reached later with the extended-release tablets than with the immediate-release tablets, the two formulations are bioequivalent with respect to the area under the plasma concentration-time curve. Bioequivalence is also achieved between the formulations for the microbiologically active metabolite, 14-hydroxy-clarithromycin. Two randomized trials in patients with acute exacerbations of chronic bronchitis (AECB) showed that a 7-day course of clarithromycin extended-release 1000 mg once daily produced clinical cure rates of 83% and 85% and bacteriologic cure rates of 86% and 92% at the test-of-cure study visit. Similar rates of cure were achieved with a 7-day course of twice-daily clarithromycin immediate-release and with a 10-day course of twice-daily amoxicillin/clavulanic acid.A 7-day course of clarithromycin extended-release 1000 mg once daily produced clinical and bacteriologic cure rates of 88% and 86%, respectively, in patients with community-acquired pneumonia (CAP). Similar cure rates were achieved in recipients of once-daily levofloxacin in the same trial. In patients with acute maxillary sinusitis, a 14-day course of either once-daily clarithromycin extended-release or twice-daily clarithromycin immediate-release produced statistically equivalent clinical cure rates of 85% and 79%, respectively. Both treatment groups achieved similar rates of radiographic success and resolution of sinusitis. Recent results indicate that clarithromycin extended-release 500 mg once daily for 5 days is also effective in the treatment of patients with streptococcal pharyngitis/tonsillitis and in the treatment of AECB. The most frequently reported drug-related events with clarithromycin extended-release were abnormal taste (7% incidence), diarrhea (6%) and nausea (3%). Most adverse drug reactions were of a mild and transient nature. In comparative clinical trials, clarithromycin extended-release had an improved gastrointestinal tolerability profile compared with the immediate-release formulation. In addition, clarithromycin extended-release was better tolerated than amoxicillin/clavulanic acid and as well tolerated as levofloxacin. Further studies are required to assess the cost-effectiveness ratio of clarithromycin relative to comparator antibacterial agents.

CONCLUSION

Clarithromycin extended-release is an effective treatment for AECB, CAP, acute maxillary sinusitis, and pharyngitis (although not approved for the latter in the US), and is administered in a convenient dosage regimen that has the potential to encourage good compliance. The reformulation modulates clarithromycin absorption kinetics thereby improving tolerability. Therefore, clarithromycin extended-release provides a useful option for the treatment of specific respiratory tract infections.

New antimicrobial cystatin C-based peptide active against gram-positive bacterial pathogens, including methicillin-resistant Staphylococcus aureus and multiresistant coagulase-negative staphylococci

We describe the synthesis and antibacterial properties of a novel antimicrobial peptidyl derivative, (2S)-2-(Nalpha-benzyloxycarbonyl-arginyl-leucylamido-1-[(E)-cinnamoylamido]-3-methylbutane, structurally based upon the inhibitory centre of the human cysteine protease inhibitor, cystatin C. The derivative, here called Cystapep 1, displayed antibacterial activity against several clinically important gram-positive bacteria. It displayed minimal inhibitory and bactericidal concentrations of about 16 microg/ml for both Staphylococcus aureus and Streptococcus pyogenes. In radial agar diffusion assays, groups A, B, C and G streptococci as well as staphylococci were generally susceptible to the action of Cystapep 1, whereas pneumococci and enterococci were less susceptible. No activity against gram-negative bacteria was observed. Cystapep 1 also showed high activity against methicillin-resistant S. aureus (MRSA) and multiantibiotic-resistant coagulase-negative staphylococci (CNS), suggesting that its mechanism of action differs from those of most currently used antibiotics.

Evolution and medicine in undergraduate education: a prescription for all biology students

The interface between evolutionary biology and the biomedical sciences promises to advance understanding of the origins of genetic and infectious diseases in humans, potentially leading to improved medical diagnostics, therapies, and public health practices. The biomedical sciences also provide unparalleled examples for evolutionary biologists to explore. However, gaps persist between evolution and medicine, for historical reasons and because they are often perceived as having disparate goals. Evolutionary biologists have a role in building a bridge between the disciplines by presenting evolutionary biology in the context of human health and medical practice to undergraduates, including premedical and preprofessional students. We suggest that students will find medical examples of evolution engaging. By making the connections between evolution and medicine clear at the undergraduate level, the stage is set for future health providers and biomedical scientists to work productively in this synthetic area. Here, we frame key evolutionary concepts in terms of human health, so that biomedical examples may be more easily incorporated into evolution courses or more specialized courses on evolutionary medicine. Our goal is to aid in building the scientific foundation in evolutionary biology for all students, and to encourage evolutionary biologists to join in the integration of evolution and medicine.

Antibiotic prescribing in primary care, adherence to guidelines and unnecessary prescribing--an Irish perspective

Background

Information about antibiotic prescribing practice in primary care is not available for Ireland, unlike other European countries. The study aimed to ascertain the types of antibiotics and the corresponding conditions seen in primary care and whether general practitioners (GPs) felt that an antibiotic was necessary at the time of consultation. This information will be vital to inform future initiatives in prudent antibiotic prescribing in primary care.

Methods

Participating GPs gathered data on all antibiotics prescribed by them in 100 consecutive patients’ consultations as well as data on the conditions being treated and whether they felt the antibiotic was necessary.

Results

171 GPs collected data on 16,899 consultations. An antibiotic was prescribed at 20.16% of these consultations. The majority were prescribed for symptoms or diagnoses associated with the respiratory system; the highest rate of prescribing in these consultations were for patients aged 15–64 years (62.23%). There is a high rate of 2^nd and 3^rd line agents being used for common ailments such as otitis media and tonsillitis. Amoxicillin, which is recommended as 1^st line in most common infections, was twice as likely to be prescribed if the prescription was for deferred used or deemed unnecessary by the GP.

Conclusion

The study demonstrates that potentially inappropriate prescribing is occurring in the adult population and the high rate of broad-spectrum antimicrobial agents is a major concern. This study also indicates that amoxicillin may be being used for its placebo effect rather than specifically for treatment of a definite bacterial infection.

Social-economic factors and irrational antibiotic use as reasons for antibiotic resistance of bacteria causing common childhood infections in primary healthcare

The most prevalent childhood bacterial infections in primary healthcare are respiratory, gastrointestinal and urogenital infections. The main aim of this paper was to consider factors (socio-economic factors and irrational antibiotic use) that contribute to the development of bacterial resistance, as well as measures that resulted in a reduction of this problem. Computerized search through the Medline of published articles on antibiotic resistance from 1996 to 2011 in English or Serbian was completed in August 2011. Combinations of used terms were antimicrobial/antibacterial/antibiotic and resistance/susceptibility in pediatric/children, and Streptococcus pneumoniae/Streptococci/Haemophilus influenzae/Salmonellae/Escherichia coli/Shigella/Staphylococcus aureus as well as antibiotics/antimicrobials/antibacterials and consumption/utilization/use. In many developing countries, antibiotic dispensing and its use in medicine, cattle breeding and agriculture are inadequately regulated, or existing laws are not being appropriately implemented. In addition, human travel contributes to antimicrobial drug resistance around the world. All of these factors have led to a very high level of bacterial resistance. On the contrary, in countries with a clearly defined and implemented legal framework concerning antibiotic prescribing, dispensing and utilization, the use of antibiotics is under constant surveillance. That resulted in a significantly lower antibacterial resistance. In conclusion, bacterial resistance could be reduced by the implementation of systemic and long-term measures at a country level as well as at all levels of healthcare. In order to reduce bacterial resistance, antibiotic use needs to be precisely regulated, and regulations should be coherent with practice. The international community must have a more active role in solving this global problem.

Fitness of Escherichia coli strains carrying expressed and partially silent IncN and IncP1 plasmids

Background

Understanding the survival of resistance plasmids in the absence of selective pressure for the antibiotic resistance genes they carry is important for assessing the value of interventions to combat resistant bacteria. Here, several poorly explored questions regarding the fitness impact of IncP1 and IncN broad host range plasmids on their bacterial hosts are examined; namely, whether related plasmids have similar fitness impacts, whether this varies according to host genetic background, and what effect antimicrobial resistance gene silencing has on fitness.

Results

For the IncP1 group pairwise in vitro growth competition demonstrated that the fitness cost of plasmid RP1 depends on the host strain. For the IncN group, plasmids R46 and N3 whose sequence is presented for the first time conferred remarkably different fitness costs despite sharing closely related backbone structures, implicating the accessory genes in fitness. Silencing of antimicrobial resistance genes was found to be beneficial for host fitness with RP1 but not for IncN plasmid pVE46.

Conclusions

These findings suggest that the fitness impact of a given plasmid on its host cannot be inferred from results obtained with other host-plasmid combinations, even if these are closely related.

Correlation of tetracycline and sulfonamide antibiotics with corresponding resistance genes and resistant bacteria in a conventional municipal wastewater treatment plant

Antibiotics and corresponding resistance genes and resistant bacteria have been considered as emerging pollutants worldwide. Wastewater treatment plants (WWTPs) are potential reservoirs contributing to the evolution and spread of antibiotic resistance. In this study, total concentrations of tetracycline and sulfonamide antibiotics in final effluent were detected at 652.6 and 261.1ng/L, respectively, and in treated sludge, concentrations were at 1150.0 and 76.0μg/kg dry weight (dw), respectively. The quantities of antibiotic resistance genes and antibiotic resistant bacteria in final effluent were quantified in the range of 9.12×10(5)-1.05×10(6) gene abundances /100mL (genomic copies/100mL) and 1.05×10(1)-3.09×10(3)CFU/mL, respectively. In treated sludge, they were quantified at concentrations of 1.00×10(8)-1.78×10(9) gene abandances/100mL and 7.08×10(6)-1.91×10(8)CFU/100mL, respectively. Significant reductions (2-3 logs, p<0.05) of antibiotic resistance genes and antibiotic resistant bacteria were observed between raw influent and final effluent. The gene abundances of tetO and tetW normalized to that of 16S rRNA genes indicated an apparent decrease as compared to sulI genes, which remained stable along each treatment stage. Significant correlations (R(2)=0.75-0.83, p<0.05) between numbers of resistant bacteria and antibiotic concentrations were observed in raw influent and final effluent. No significance (R(2)=0.15, p>0.05) was found between tet genes (tetO and tetW) with concentration of tetracyclines identified in wastewater, while a significant correlation (R(2)=0.97, p<0.05) was observed for sulI gene and total concentration of sulfonamides. Correlations of the quantities of antibiotic resistance genes and antibiotic resistant bacteria with corresponding concentrations of antibiotics in sludge samples were found to be considerably weak (R(2)=0.003-0.07).

Population genomics: an investigative tool for epidemics

This Commentary highlights the article by Fittipaldi et al describing the emergence and epidemic spread of an emm59 strain of group A streptococcus.

Effectiveness of multifaceted educational programme to reduce antibiotic dispensing in primary care: practice based randomised controlled trial

OBJECTIVE

To evaluate the effectiveness and costs of a multifaceted flexible educational programme aimed at reducing antibiotic dispensing at the practice level in primary care.

DESIGN

Randomised controlled trial with general practices as the unit of randomisation and analysis. Clinicians and researchers were blinded to group allocation until after randomisation.

SETTING

68 general practices with about 480,000 patients in Wales, United Kingdom.

PARTICIPANTS

34 practices were randomised to receive the educational programme and 34 practices to be controls. 139 clinicians from the intervention practices and 124 from control practices had agreed to participate before randomisation. Practice level data covering all the clinicians in the 68 practices were analysed.

INTERVENTIONS

Intervention practices followed the Stemming the Tide of Antibiotic Resistance (STAR) educational programme, which included a practice based seminar reflecting on the practices' own dispensing and resistance data, online educational elements, and practising consulting skills in routine care. Control practices provided usual care.

MAIN OUTCOME MEASURES

Total numbers of oral antibiotic items dispensed for all causes per 1000 practice patients in the year after the intervention, adjusted for the previous year's dispensing. Secondary outcomes included reconsultations, admissions to hospital for selected causes, and costs.

RESULTS

The rate of oral antibiotic dispensing (items per 1000 registered patients) decreased by 14.1 in the intervention group but increased by 12.1 in the control group, a net difference of 26.1. After adjustment for baseline dispensing rate, this amounted to a 4.2% (95% confidence interval 0.6% to 7.7%) reduction in total oral antibiotic dispensing for the year in the intervention group relative to the control group (P=0.02). Reductions were found for all classes of antibiotics other than penicillinase-resistant penicillins but were largest and significant individually for phenoxymethylpenicillins (penicillin V) (7.3%, 0.4% to 13.7%) and macrolides (7.7%, 1.1% to 13.8%). There were no significant differences between intervention and control practices in the number of admissions to hospital or in reconsultations for a respiratory tract infection within seven days of an index consultation. The mean cost of the programme was £2923 (€3491, $4572) per practice (SD £1187). There was a 5.5% reduction in the cost of dispensed antibiotics in the intervention group compared with the control group (-0.4% to 11.4%), equivalent to a reduction of about £830 a year for an average intervention practice.

CONCLUSION

The STAR educational programme led to reductions in all cause oral antibiotic dispensing over the subsequent year with no significant change in admissions to hospital, reconsultations, or costs. Trial registration ISRCT No 63355948.