Antibiotic resistance in sputum isolates of Streptococcus pneumoniae in chronic obstructive pulmonary disease is related to antibiotic exposure

Prevalence, Pattern, Risks Factors and Consequences of Antibiotic Resistance in COPD: A Systematic Review

A concern of antibiotic use in chronic obstructive pulmonary disease (COPD) is the emergence and propagation of antimicrobial resistance (AMR). A systematic review was conducted to determine prevalence, pattern, risk factors and consequences of AMR in COPD. Bibliographic databases were searched from inception to November 2020, with no language restrictions, including studies of any design that included patients with COPD and reported prevalence and pattern of AMR. 2748 unique titles and abstracts were identified, of which 63 articles, comprising 26,387 patients, met inclusion criteria. Forty-four (69.8%) studies were performed during acute exacerbation. The median prevalence of AMR ranged from 0-100% for Pseudomonas aeruginosa, Moraxella catarrhalis, Klebsiella pneumoniae and Acinetobacter baumannii. Median resistance rates of H influenzae and S pneumoniae were lower by comparison, with maximum rates ≤40% and ≤46%, respectively, and higher for Staphylococcus aureus. There was a trend towards higher rates of AMR in patients with poorer lung function and greater incidence of previous antibiotic exposure and hospitalisation. The impact of AMR on mortality was unclear. Data regarding antimicrobial susceptibility testing techniques and the impact of other risk factors or consequences of AMR were variable or not reported. This is the first review to systematically unify data regarding AMR in COPD. AMR is relatively common and strategies to optimise antibiotic use could be valuable to prevent the currently under-investigated potential adverse consequences of AMR.Supplemental data for this article is available online at https://doi.org/10.1080/15412555.2021.2000957 .

Two-day versus seven-day course of levofloxacin in acute COPD exacerbation: a randomized controlled trial

INTRODUCTION

Duration of antibiotic treatment in acute exacerbation of COPD (AECOPD) is most commonly based on expert opinion. Typical administration periods range from 5 to 7 days. A 2-day course with levofloxacin was not previously assessed. We performed a randomized clinical trial to evaluate the efficacy of 2-day versus 7-day treatment with levofloxacin in patients with AECOPD.

METHODS AND ANALYSIS

Patients with AECOPD were randomized to receive levofloxacin for 2 days and 5 days placebo (n = 155) or levofloxacin for 7 days (n = 155). All patients received a common dose of intravenous prednisone daily for 5 days. The primary outcome measure was cure rate, and secondary outcomes included need for additional antibiotics, ICU admission rate, re-exacerbation rate, death rate, and exacerbation-free interval (EFI) within 1-year follow-up. The study protocol has been prepared in accordance with the revised Helsinki Declaration for Biomedical Research Involving Human Subjects and Guidelines for Good Clinical Practice. The study was approved by ethics committees of all participating centers prior to implementation (Monastir and Sousse Universities).

RESULTS

310 patients were randomized to receive 2-day course of levofloxacin (n = 155) or 7-day course (n = 155). Cure rate was 79.3% (n = 123) and 74.2% (n = 115), respectively, in 2-day and 7-day groups [OR 1.3; 95% CI 0.78-2.2 (p = 0.28)]. Need for additional antibiotics rate was 3.2% and 1.9% in the 2-day group and 7-day group, respectively; (p = 0.43). ICU admission rate was not significantly different between both groups. One-year re-exacerbation rate was 34.8% (n = 54) in 2-day group versus 29% (n = 45) in 7-day group (p = 0.19); the EFI was 121 days (interquartile range, 99-149) versus 110 days (interquartile range, 89-132) in 2-day and 7-day treatment groups, respectively; (p = 0.73). One-year death rate was not significantly different between the 2 groups, 5.2% versus 7.1% in the 2-day group and 7-day group, respectively; (p = 0.26). No difference in adverse effects was detected.

CONCLUSION

Levofloxacin once daily for 2 days is not inferior to 7 days with respect to cure rate, need for additional antibiotics and hospital readmission in AECOPD. Our findings would improve patient compliance and reduce the incidence of bacterial resistance and adverse effects.

2-Day versus C-reactive protein guided antibiotherapy with levofloxacin in acute COPD exacerbation: A randomized controlled trial

INTRODUCTION

Duration of antibiotic treatment in acute exacerbation of COPD (AECOPD) is most commonly based on expert opinion. Biomarker guided strategy is increasingly recommended to limit unnecessary antibiotic use. We performed a randomized controlled study to evaluate the efficacy of 2-day versus C-reactive protein (CRP)-guided treatment with levofloxacin in patients with AECOPD.

METHODS

Patients with AECOPD were randomized to receive oral levofloxacin daily for 7 days unless the serum CRP level decreased by at least 50% from the baseline value or levofloxacin for two days; thereafter, oral placebo tablet was prescribed according to the CRP. The primary outcome measure was cure rate, and secondary outcome included need for additional antibiotics, intensive care unit (ICU) admission, exacerbation rates and exacerbation free interval (EFI) within one-year follow-up.

RESULTS

In intention to treat (ITT) analysis, cure rate was 76.1% (n = 118) and 79.3% (n = 123) respectively in 2-day and CRP-guided groups. In per protocol (PP) analysis, cure rate was 73% (n = 92) and 70.4% (n = 88) respectively in 2-day and CRP-guided groups. The difference between the two groups was not significant. The need for additional antibiotics and ICU admission rates were not significantly different between the two groups. One-year exacerbation rate was 27% (n = 42) in 2-day group versus 30.3% (n = 47) in CRP-guided group (p = 0.53); the EFI was 125 days (interquartile range, 100-151) versus 100 days (interquartile range, 78-123) in 2-day and CRP-guided groups respectively (p = 0.45). No difference in adverse effects was detected.

CONCLUSION

Levofloxacin once daily for 2 days had similar efficacy compared to CRP-guided in AECOPD. This short course treatment decreased antibiotic consumption which would improve patient compliance and reduce adverse effects.

Use of Oral Tetracyclines in the Treatment of Adult Patients with Community-Acquired Bacterial Pneumonia: A Literature Review on the Often-Overlooked Antibiotic Class

Oral tetracyclines have been used in clinical practice for over 60 years. Overall, one of the most common indications for use of oral tetracyclines is for treatment of adult outpatients with lower respiratory tract infections, including community-acquired pneumonia (CAP). Despite the longstanding use of oral tetracyclines, practice patterns indicate that they are often considered after other guideline-concordant oral CAP treatment options (namely macrolides, fluoroquinolones, and β-lactams). However, there are growing resistance or safety concerns with the available oral agents listed for outpatients with CAP in the updated American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) CAP guidelines, especially among patients with comorbidities or notable risk factors for resistant pathogens. Given the need for alternative oral agents to macrolides, fluoroquinolones, and beta-lactams for adult outpatients with CAP, this review summarizes the literature on the use of oral tetracyclines (i.e., doxycycline, minocycline, and omadacycline) for this indication. As part of this review, we described their mechanism of action, common mechanisms of resistance, susceptibility profiles against common CAP pathogens, pharmacokinetics, pharmacodynamics, clinical data, and safety. The intent of the review is to highlight the important considerations when deciding between doxycycline, minocycline, and omadacycline for an adult outpatient with CAP in situations in which use of an oral tetracycline is warranted.

Treatment of Acute Exacerbations in Chronic Obstructive Pulmonary Disease

Management of a chronic obstructive pulmonary disease (COPD) exacerbation begins with an accurate diagnosis. Although more than 80% of exacerbations are managed on an outpatient basis, hospitalization is all too common and associated with considerable health care costs and mortality. Irrespective of the site of treatment, the treatment modalities are the same. Noninvasive ventilation has greatly decreased the mortality in exacerbations that require ventilatory support. Across the range of exacerbation severity, treatment failure and relapses are frequent, and should be carefully evaluated. New therapeutic options to address infection and inflammation in COPD are needed to improve the outcome of exacerbations.

C-reactive protein testing to guide antibiotic prescribing for COPD exacerbations: A protocol for systematic review and meta-analysis

BACKGROUND

The use of antibiotics in the acute exacerbations of chronic obstructive pulmonary disease (COPD) remains controversial. Serum C-reactive protein (CRP), a sensitive biomarker for systemic inflammation and tissue damage, is a good indicator of lower respiratory tract bacterial infection. However, due to the small sample size of the existing studies, the clinical value of CRP in guiding the use of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) antibiotics is insufficient. The aim of this study was to evaluate the value of CRP-guided treatment strategies for AECOPD patients.

METHODS

This review summarizes and meta-analyses randomized controlled trials (RCTs) of CRP guiding antibiotic prescribing for COPD exacerbations. RCTs compare either usual-care or the GOLD strategy have been included. The following electronic databases have been searched: PubMed, Cochrane Library, Embase, CNKI, CBM, VIP, and Wanfang Data. The methodologic quality of RCTs has been assessed using the Cochrane risk assessment tool. All trials included are analyzed according to the criteria of the Cochrane Handbook. Review Manager 5.3, R-3.5.1 software, and GRADE pro GDT web solution are used for data synthesis and analysis.

RESULTS

This review evaluates the effects of CRP testing on the antibiotic use, CCQ, EQ-5D utility scores and adverse events in patients with COPD exacerbations.

CONCLUSION

This review provides clear evidence that CRP testing can reduce the use of antibiotics in patients with AECOPD without causing harm.

Acute exacerbations in chronic obstructive pulmonary disease: should we use antibiotics and if so, which ones?

PURPOSE OF REVIEW

Acute exacerbations are a major cause of morbidity and mortality in chronic obstructive pulmonary disease (COPD) with evidence suggesting at least 50% of exacerbations involve bacteria that benefit from antibiotic treatment. Here, we review the most relevant data regarding the use of antibiotics in exacerbations of COPD and provide insights on the selection of initial antibiotic therapy for their treatment.

RECENT FINDINGS

Identification of bacterial exacerbations still relies on clinical assessment rather than laboratory biomarkers. Several recent studies, including a meta-analysis and placebo-controlled trials, demonstrate improved outcomes with antibiotics in all but mild exacerbations of COPD, including both inpatient and outpatient. A broader antibiotic regimen should be used for patients who have risk factors for poor outcomes. A risk-stratification approach can guide antibiotic choice, although the stratification algorithm still needs to be validated in a randomized controlled trial.

SUMMARY

The use of antibiotics for the treatment of moderate-to-severe suspected bacterial exacerbations in COPD is supported by published trials and evidence-based systematic reviews. Recent trials also show differences in outcomes based on antibiotic choice. More research is necessary to evaluate risk stratification approaches when selecting initial antibiotic therapy.

C-reactive protein point-of-care testing for safely reducing antibiotics for acute exacerbations of chronic obstructive pulmonary disease: the PACE RCT

BACKGROUND

Most patients presenting with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in primary care are prescribed antibiotics, but these may not be beneficial, and they can cause side effects and increase the risk of subsequent resistant infections. Point-of-care tests (POCTs) could safely reduce inappropriate antibiotic prescribing and antimicrobial resistance.

OBJECTIVE

To determine whether or not the use of a C-reactive protein (CRP) POCT to guide prescribing decisions for AECOPD reduces antibiotic consumption without having a negative impact on chronic obstructive pulmonary disease (COPD) health status and is cost-effective.

DESIGN

A multicentre, parallel-arm, randomised controlled open trial with an embedded process, and a health economic evaluation.

SETTING

General practices in Wales and England. A UK NHS perspective was used for the economic analysis.

PARTICIPANTS

Adults (aged ≥ 40 years) with a primary care diagnosis of COPD, presenting with an AECOPD (with at least one of increased dyspnoea, increased sputum volume and increased sputum purulence) of between 24 hours' and 21 days' duration.

INTERVENTION

CRP POCTs to guide antibiotic prescribing decisions for AECOPD, compared with usual care (no CRP POCT), using remote online randomisation.

MAIN OUTCOME MEASURES

Patient-reported antibiotic consumption for AECOPD within 4 weeks post randomisation and COPD health status as measured with the Clinical COPD Questionnaire (CCQ) at 2 weeks. For the economic evaluation, patient-reported resource use and the EuroQol-5 Dimensions were included.

RESULTS

In total, 653 participants were randomised from 86 general practices. Three withdrew consent and one was randomised in error, leaving 324 participants in the usual-care arm and 325 participants in the CRP POCT arm. Antibiotics were consumed for AECOPD by 212 out of 274 participants (77.4%) and 150 out of 263 participants (57.0%) in the usual-care and CRP POCT arm, respectively [adjusted odds ratio 0.31, 95% confidence interval (CI) 0.20 to 0.47]. The CCQ analysis comprised 282 and 281 participants in the usual-care and CRP POCT arms, respectively, and the adjusted mean CCQ score difference at 2 weeks was 0.19 points (two-sided 90% CI -0.33 to -0.05 points). The upper limit of the CI did not contain the prespecified non-inferiority margin of 0.3. The total cost from a NHS perspective at 4 weeks was £17.59 per patient higher in the CRP POCT arm (95% CI -£34.80 to £69.98; p = 0.408). The mean incremental cost-effectiveness ratios were £222 per 1% reduction in antibiotic consumption compared with usual care at 4 weeks and £15,251 per quality-adjusted life-year gained at 6 months with no significant changes in sensitivity analyses. Patients and clinicians were generally supportive of including CRP POCT in the assessment of AECOPD.

CONCLUSIONS

A CRP POCT diagnostic strategy achieved meaningful reductions in patient-reported antibiotic consumption without impairing COPD health status or increasing costs. There were no associated harms and both patients and clinicians valued the diagnostic strategy.

FUTURE WORK

Implementation studies that also build on our qualitative findings could help determine the effect of this intervention over the longer term.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN24346473.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 15. See the NIHR Journals Library website for further project information.

New therapeutic targets for the prevention of infectious acute exacerbations of COPD: role of epithelial adhesion molecules and inflammatory pathways

Chronic respiratory diseases are among the leading causes of mortality worldwide, with the major contributor, chronic obstructive pulmonary disease (COPD) accounting for approximately 3 million deaths annually. Frequent acute exacerbations (AEs) of COPD (AECOPD) drive clinical and functional decline in COPD and are associated with accelerated loss of lung function, increased mortality, decreased health-related quality of life and significant economic costs. Infections with a small subgroup of pathogens precipitate the majority of AEs and consequently constitute a significant comorbidity in COPD. However, current pharmacological interventions are ineffective in preventing infectious exacerbations and their treatment is compromised by the rapid development of antibiotic resistance. Thus, alternative preventative therapies need to be considered. Pathogen adherence to the pulmonary epithelium through host receptors is the prerequisite step for invasion and subsequent infection of surrounding structures. Thus, disruption of bacterial-host cell interactions with receptor antagonists or modulation of the ensuing inflammatory profile present attractive avenues for therapeutic development. This review explores key mediators of pathogen-host interactions that may offer new therapeutic targets with the potential to prevent viral/bacterial-mediated AECOPD. There are several conceptual and methodological hurdles hampering the development of new therapies that require further research and resolution.

C-Reactive Protein Testing to Guide Antibiotic Prescribing for COPD Exacerbations

BACKGROUND

Point-of-care testing of C-reactive protein (CRP) may be a way to reduce unnecessary use of antibiotics without harming patients who have acute exacerbations of chronic obstructive pulmonary disease (COPD).

METHODS

We performed a multicenter, open-label, randomized, controlled trial involving patients with a diagnosis of COPD in their primary care clinical record who consulted a clinician at 1 of 86 general medical practices in England and Wales for an acute exacerbation of COPD. The patients were assigned to receive usual care guided by CRP point-of-care testing (CRP-guided group) or usual care alone (usual-care group). The primary outcomes were patient-reported use of antibiotics for acute exacerbations of COPD within 4 weeks after randomization (to show superiority) and COPD-related health status at 2 weeks after randomization, as measured by the Clinical COPD Questionnaire, a 10-item scale with scores ranging from 0 (very good COPD health status) to 6 (extremely poor COPD health status) (to show noninferiority).

RESULTS

A total of 653 patients underwent randomization. Fewer patients in the CRP-guided group reported antibiotic use than in the usual-care group (57.0% vs. 77.4%; adjusted odds ratio, 0.31; 95% confidence interval [CI], 0.20 to 0.47). The adjusted mean difference in the total score on the Clinical COPD Questionnaire at 2 weeks was -0.19 points (two-sided 90% CI, -0.33 to -0.05) in favor of the CRP-guided group. The antibiotic prescribing decisions made by clinicians at the initial consultation were ascertained for all but 1 patient, and antibiotic prescriptions issued over the first 4 weeks of follow-up were ascertained for 96.9% of the patients. A lower percentage of patients in the CRP-guided group than in the usual-care group received an antibiotic prescription at the initial consultation (47.7% vs. 69.7%, for a difference of 22.0 percentage points; adjusted odds ratio, 0.31; 95% CI, 0.21 to 0.45) and during the first 4 weeks of follow-up (59.1% vs. 79.7%, for a difference of 20.6 percentage points; adjusted odds ratio, 0.30; 95% CI, 0.20 to 0.46). Two patients in the usual-care group died within 4 weeks after randomization from causes considered by the investigators to be unrelated to trial participation.

CONCLUSIONS

CRP-guided prescribing of antibiotics for exacerbations of COPD in primary care clinics resulted in a lower percentage of patients who reported antibiotic use and who received antibiotic prescriptions from clinicians, with no evidence of harm. (Funded by the National Institute for Health Research Health Technology Assessment Program; PACE Current Controlled Trials number, ISRCTN24346473.).

CRP-guided antibiotic treatment in acute exacerbations of COPD in hospital admissions

The role of antibiotics in acute exacerbations of chronic obstructive pulmonary disease (COPD) is controversial and a biomarker identifying patients who benefit from antibiotics is mandatory. We performed a randomised, controlled trial in patients with acute exacerbations of COPD, comparing C-reactive protein (CRP)-guided antibiotic treatment to patient reported symptoms in accordance with the Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy, in order to show a reduction in antibiotic prescription.Patients hospitalised with acute exacerbations of COPD were randomised to receive antibiotics based either on the GOLD strategy or according to the CRP strategy (CRP ≥50 mg·L^-1).In total, 101 patients were randomised to the CRP group and 119 to the GOLD group. Fewer patients in the CRP group were treated with antibiotics compared to the GOLD group (31.7% versus 46.2%, p=0.028; adjusted odds ratio (OR) 0.178, 95% CI 0.077-0.411, p=0.029). The 30-day treatment failure rate was nearly equal (44.5% in the CRP group versus 45.5% in the GOLD-group, p=0.881; adjusted OR 1.146, 95% CI 0.649-1.187, p=0.630), as was the time to next exacerbation (32 days in the CRP group versus 28 days in the GOLD group, p=0.713; adjusted hazard ratio 0.878, 95% CI 0.649-1.187, p=0.398). Length of stay was similar in both groups (7 days in the CRP group versus 6 days in the GOLD group, p=0.206). On day-30, no difference in symptom score, quality of life or serious adverse events was detected.Use of CRP as a biomarker to guide antibiotic treatment in severe acute exacerbations of COPD leads to a significant reduction in antibiotic treatment. In the present study, no differences in adverse events between both groups were found. Further research is needed for the generalisability of these findings.

Azithromycin Pharmacodynamics against Persistent Haemophilus influenzae in Chronic Obstructive Pulmonary Disease

The pharmacodynamic profile of azithromycin against persistent strains of nontypeable Haemophilus influenzae (NTHi) from chronic obstructive pulmonary disease (COPD) patients was characterized. Azithromycin displayed differential concentration-dependent activities (R² ≥ 0.988); the pharmacodynamic response was attenuated when we compared the "first" and "last" strains of NTHi that persisted in the airways of the same patient for 819 days (the 50% effective concentration [EC₅₀] increased more than 50 times [0.0821 mg/liter versus 4.23 mg/liter]). In the hollow-fiber infection model, NTHi viability was maintained throughout simulated azithromycin (Zithromax) Z-Pak regimens over 10 days.

General practitioner use of a C-reactive protein point-of-care test to help target antibiotic prescribing in patients with acute exacerbations of chronic obstructive pulmonary disease (the PACE study): study protocol for a randomised controlled trial

Background

Most patients presenting with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in primary care are prescribed an antibiotic, which may not always be appropriate and may cause harm. C-reactive protein (CRP) is an acute-phase biomarker that can be rapidly measured at the point of care and may predict benefit from antibiotic treatment in AECOPD. It is not clear whether the addition of a CRP point-of-care test (POCT) to clinical assessment leads to a reduction in antibiotic consumption without having a negative impact on COPD health status.

Methods/design

This is a multicentre, individually randomised controlled trial (RCT) aiming to include 650 participants with a diagnosis of AECOPD in primary care. Participants will be randomised to be managed according to usual care (control) or with the addition of a CRP POCT to guide antibiotic prescribing. Antibiotic consumption for AECOPD within 4 weeks post randomisation and COPD health status (total score) measured by the Clinical COPD Questionnaire (CCQ) at 2 weeks post randomisation will be co-primary outcomes. Primary analysis (by intention-to-treat) will determine differences in antibiotic consumption for superiority and COPD health status for non-inferiority. Secondary outcomes include: COPD health status, CCQ domain scores, use of other COPD treatments (weeks 1, 2 and 4), EQ-5D utility scores (weeks 1, 2 and 4 and month 6), disease-specific, health-related quality of life (HRQoL) at 6 months, all-cause antibiotic consumption (antibiotic use for any condition) during first 4 weeks post randomisation, total antibiotic consumption (number of days during first 4 weeks of antibiotic consumed for AECOPD/any reason), antibiotic prescribing at the index consultation and during following 4 weeks, adverse effects over the first 4 weeks, incidence of pneumonia (weeks 4 and 6 months), health care resource use and cost comparison over the 6 months following randomisation. Prevalence and resistance profiles of bacteria will be assessed using throat and sputum samples collected at baseline and 4-week follow-up. A health economic evaluation and qualitative process evaluation will be carried out.

Discussion

If shown to be effective (i.e. leads to a reduction in antibiotic use with no worse COPD health status), the use of the CRP POCT could lead to better outcomes for patients with AECOPD and help reduce selective pressures driving the development of antimicrobial resistance. PACE will be one of the first studies to evaluate the cost-effectiveness of a POCT biomarker to guide clinical decision-making in primary care on patient-reported outcomes, antibiotic prescribing and antibiotic resistance for AECOPD.

Trial registration

ISRCTN registry, ID: ISRCTN24346473. Registered on 20 August 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2144-8) contains supplementary material, which is available to authorized users.

Virulence determinants of Moraxella catarrhalis: distribution and considerations for vaccine development

Moraxella catarrhalis is a human-restricted opportunistic bacterial pathogen of the respiratory mucosa. It frequently colonizes the nasopharynx asymptomatically, but is also an important causative agent of otitis media (OM) in children, and plays a significant role in acute exacerbations of chronic obstructive pulmonary disease (COPD) in adults. As the current treatment options for M. catarrhalis infection in OM and exacerbations of COPD are often ineffective, the development of an efficacious vaccine is warranted. However, no vaccine candidates for M. catarrhalis have progressed to clinical trials, and information regarding the distribution of M. catarrhalis virulence factors and vaccine candidates is inconsistent in the literature. It is largely unknown if virulence is associated with particular strains or subpopulations of M. catarrhalis, or if differences in clinical manifestation can be attributed to the heterogeneous expression of specific M. catarrhalis virulence factors in the circulating population. Further investigation of the distribution of M. catarrhalis virulence factors in the context of carriage and disease is required so that vaccine development may be targeted at relevant antigens that are conserved among disease-causing strains. The challenge of determining which of the proposed M. catarrhalis virulence factors are relevant to human disease is amplified by the lack of a standardized M. catarrhalis typing system to facilitate direct comparisons of worldwide isolates. Here we summarize and evaluate proposed relationships between M. catarrhalis subpopulations and specific virulence factors in the context of colonization and disease, as well as the current methods used to infer these associations.

The role of acute and chronic respiratory colonization and infections in the pathogenesis of COPD

COPD is a major global concern, increasingly so in the context of ageing populations. The role of infections in disease pathogenesis and progression is known to be important, yet the mechanisms involved remain to be fully elucidated. While COPD pathogens such as Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae are strongly associated with acute exacerbations of COPD (AECOPD), the clinical relevance of these pathogens in stable COPD patients remains unclear. Immune responses in stable and colonized COPD patients are comparable to those detected in AECOPD, supporting a role for chronic colonization in COPD pathogenesis through perpetuation of deleterious immune responses. Advances in molecular diagnostics and metagenomics now allow the assessment of microbe-COPD interactions with unprecedented personalization and precision, revealing changes in microbiota associated with the COPD disease state. As microbial changes associated with AECOPD, disease severity and therapeutic intervention become apparent, a renewed focus has been placed on the microbiology of COPD and the characterization of the lung microbiome in both its acute and chronic states. Characterization of bacterial, viral and fungal microbiota as part of the lung microbiome has the potential to reveal previously unrecognized prognostic markers of COPD that predict disease outcome or infection susceptibility. Addressing such knowledge gaps will ultimately lead to a more complete understanding of the microbe-host interplay in COPD. This will permit clearer distinctions between acute and chronic infections and more granular patient stratification that will enable better management of these features and of COPD.

Review of antibiotic use in respiratory disorders at a regional hospital in Queensland

tAdherence to antibiotic guidelines has been shown to improve outcomes in several clinical situations.Respiratory conditions are a major cause of mortality and morbidity in Queensland. A recent study showedlow levels of compliance with antibiotic guidelines in a Queensland metropolitan hospital. We undertookan audit of antibiotic use in a regional Queensland hospital against Therapeutic Guideline recommenda-tions. Therapeutic Guideline recommendations were followed in 16% of cases with ceftriaxone the mostcommonly prescribed. Re-admission rate within 28 days was for 53%, 26%, 11% and 5% respectively forceftriaxone, benzylpenicillin, amoxicillin/clavulanate and ceftriaxone combined doxycycline. Less thanhalf of patients treated for pneumonia had concordant radiographic changes. Admission via the emer-gency department may be a factor in the preference for intravenous injection of ceftriaxone and presenceof non-infective co-morbidities may also contribute to re-admissions. Considerable challenges exist inimproving compliance with antibiotic guidelines which can improve patient outcomes and antibioticstewardship.

Adherence to guideline-based antibiotic treatment for acute exacerbations of chronic obstructive pulmonary disease in an Australian tertiary hospital

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are an important cause of acute hospital admissions and incur significant costs, which include antibiotic costs.

AIMS

This study aimed to (i) define antibiotic prescribing practice in patients admitted to a tertiary hospital with AECOPD and compare this with current locally and nationally recognised antibiotic prescribing guidelines and (ii) correlate variations in guideline-concordant antibiotic prescribing with mean length of stay (LOS) and rates of unplanned readmission to hospital.

METHODS

Retrospective case series of 84 consecutive patients with uncomplicated AECOPD who met pre-specified selection criteria.

RESULTS

Seventy-two of 84 participants (85.7%) received guideline-discordant antibiotics, of whom the majority (76%) received intravenous antibiotics. Mean LOS was significantly lower among patients receiving guideline-concordant therapy compared with those receiving guideline-discordant therapy (mean 1.6 days vs 3.7 days; P = 0.002). There was no significant difference between groups in rates of readmission. Estimated excess costs per patient associated with guideline-discordant therapy equalled $2642 which, if eliminated, would save approximately $300 000 per annum.

CONCLUSION

In a tertiary hospital, Australian guidelines for treating patients with an AECOPD were rarely followed. The use of guideline-discordant therapy resulted in longer hospital stays and incurred greater costs. Studies are required to determine the reasons behind such discordant practice and to develop initiatives to improve antibiotic prescribing.

Role of infections

This article represents a review of the current literature on the role of infection in the pathogenesis of chronic obstructive pulmonary disease (COPD), in stable disease, exacerbations, and pneumonia. It outlines the complex interactions between respiratory pathogens and host immune defenses that underlie the clinical manifestations of infection in COPD.

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.

Lung microbiology and exacerbations in COPD

Chronic obstructive pulmonary disease (COPD) is the most common chronic respiratory condition in adults and is characterized by progressive airflow limitation that is not fully reversible. The main etiological agents linked with COPD are cigarette smoking and biomass exposure but respiratory infection is believed to play a major role in the pathogenesis of both stable COPD and in acute exacerbations. Acute exacerbations are associated with more rapid decline in lung function and impaired quality of life and are the major causes of morbidity and mortality in COPD. Preventing exacerbations is a major therapeutic goal but currently available treatments for exacerbations are not very effective. Historically, bacteria were considered the main infective cause of exacerbations but with the development of new diagnostic techniques, respiratory viruses are also frequently detected in COPD exacerbations. This article aims to provide a state-of-the art review of current knowledge regarding the role of infection in COPD, highlight the areas of ongoing debate and controversy, and outline emerging technologies and therapies that will influence future diagnostic and therapeutic pathways in COPD.