Epidemiology and treatment of chronic bronchitis and its exacerbations

Antimicrobial susceptibility of common pathogens from community-acquired lower respiratory tract infections in Estonia

Antimicrobial resistance among clinical isolates of Streptococcus pneumoniae (n = 49), Haemophilus influenzae (n = 66) and Moraxella catarrhalis (n = 25) from adults with community-acquired lower respiratory tract infections (CALRTI) was assessed in a national surveillance study in Southern Estonia during 2000-2003. In S. pneumoniae, no penicillin resistance and only 2.0% resistance to clarithromycin was present, although intermediate resistance to trimethoprim-sulphamethoxazole (TMP-SMX) reached 24.5%. Beta-lactamase production rate was 96.0% in M. catarrhalis, but only 3.0% in H. influenzae. Both Gram-negative strains lacked resistance to ciprofloxacin. Clarithromycin resistance was 12% in M. catarrhalis but lacking among H. influenzae (except for 18.2% intermediate resistance). Resistance to TMP-SMX was 12.0% and 24.2% in M. catarrhalis and H. influenzae, respectively. In summary, a favorable resistance pattern of the main CALRTI pathogens is preserved in Estonia to core antibacterials. Nevertheless, use of TMP-SMX in CALRTI is discouraged and clinical response should be carefully monitored, when clarithromycin is chosen against M. catarrhalis or H. influenzae.

Community-Acquired Respiratory Complications in the Intensive Care Unit: Pneumonia and Acute Exacerbations of COPD

This chapter will review the two most common lower respiratory tract infections in the intensive care unit (ICU), community-acquired pneumonia (CAP) and acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In addition we will provide an overview of the topics including recommendations for the diagnosis and treatment.

Eradication of H. influenzae in AECB: A pooled analysis of moxifloxacin phase III trials compared with macrolide agents

Haemophilus influenzae is the most common bacterial pathogen associated with acute exacerbations of chronic bronchitis (AECB). This study determined the rate of bacterial eradication of H. influenzae during AECB treated with either macrolides or moxifloxacin. Adult AECB patients with H. influenzae were included in a pooled analysis of four double-blind, multicentre, randomised trials. Patients received either moxifloxacin (400 mg qd for 5-10 days) or macrolides (azithromycin 500 mg/250 mg qd for 5 days or clarithromycin 500 mg bid for 5-10 days). Bacterial eradication and clinical success were recorded at the test-of-cure visit (7-37 days post-therapy). Of 2555 patients in the intent-to-treat population, 910 were microbiologically valid and 292 (32%) had H. influenzae cultured at baseline. Bacterial eradication of H. influenzae was significantly higher with moxifloxacin vs. macrolide-treated patients (93.0% [133/143] vs. 73.2% [109/149], respectively, P = 0.001). Moxifloxacin also demonstrated higher eradication rates compared with azithromycin (96.8% vs. 84.6%, P = 0.019) and clarithromycin (90.1% vs. 64.2%, P = 0.001) analysed separately. Clinical success was 89.5% (128/143) for moxifloxacin vs. 85.2% (127/149) for the macrolide group (P = 0.278); similar results were found when moxifloxacin was compared individually with each macrolide. For patients with AECB due to H. influenzae, moxifloxacin provided superior bacterial eradication rates than macrolide therapy.

Moxifloxacin versus levofloxacin against acute exacerbations of chronic bronchitis: The Latin American Cohort

We compared the efficacy and safety of moxifloxacin and levofloxacin for the treatment of patients with acute exacerbations of chronic bronchitis (AECB) using a prospective, randomized, double blind, parallel-group clinical trial design. A total of 563 patients with AECB were enrolled (437 efficacy-valid) at 34 centers in Mexico, Argentina, Brazil, Colombia, and Peru. Patients were randomized to oral therapy with either moxifloxacin 400 mg once daily for 5 days or levofloxacin 500 mg once daily for 7 days. Clinical success was achieved in 201 out of 221 (91.0%) patients in the moxifloxacin group, and in 203 out of 216 (94.0%) in the levofloxacin group, indicating that moxifloxacin is equivalently effective to levofloxacin. Bacteriologic eradication or presumed eradication was also similar in the two treatment groups: 92.8% in the moxifloxacin group and 93.8% in the levofloxacin group. Nausea was the most common drug-related adverse event in each treatment group. The rate of discontinuation because of adverse events was very low (2%). In conclusion, a 5-day course of moxifloxacin is clinically and bacteriologically equivalent to a 7-day course of levofloxacin in the treatment of patients with AECB. The short treatment duration with moxifloxacin may have compliance advantages over other currently used therapies in the 'real-life' clinical setting.

Macrolide immunomodulatory effects and symptom resolution in acute exacerbation of chronic bronchitis and acute maxillary sinusitis: a focus on clarithromycin

Bacterial respiratory tract infections are common in the primary care setting and patients often seek the assistance of a healthcare professional in order to achieve resolution of their symptoms. Antibiotic agents that offer rapid symptom relief, in addition to excellent bacteriological and clinical cure, are highly desired. Macrolides have proven to be highly effective in treating acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis. In addition, immunomodulatory effects that may contribute to symptom resolution have been reported. This article reviews current literature on symptom resolution in acute bacterial exacerbations of chronic bronchitis and acute maxillary sinusitis, with a focus on clarithromycin, and explores the potential mechanisms that may contribute to this action.

Virus infection in exacerbations of chronic obstructive pulmonary disease requiring ventilation

Objectives

We aimed to characterise and quantify the incidence of common infectious agents in acute exacerbations of chronic obstructive pulmonary disease (COPD) requiring ventilation, with a focus on respiratory viruses.

Design

An epidemiological study conducted over 3 years.

Setting

A 12-bed intensive care unit (ICU).

Participants

ICU patients over 45 years of age with a primary diagnosis of COPD exacerbation requiring non-invasive ventilation (NIV) or ventilation via endotracheal tube (ETT).

Materials and methods

Nasopharyngeal aspirates (NPA) and posterior pharyngeal swabs (PS) were tested for viruses with immunofluorescence assay (IFA), virus culture (VC) and polymerase chain reaction (PCR). Paired virus and atypical pneumonia serology assays were taken. Blood, sputum and endotracheal aspirates were cultured for bacteria.

Results

107 episodes in 105 patients were recorded. Twenty-three (21%) died within 28 days. A probable infectious aetiology was found in 69 patient episodes (64%). A virus was identified in 46 cases (43%), being the sole organism in 35 cases (33%) and part of a mixed infection in 11 cases (10%). A probable bacterial aetiology was found in 25 cases (23%). There was no statistically significant difference in clinical characteristics or outcomes between the group with virus infections and that without.

Conclusion

Forty-six (43%) of the patients with COPD exacerbation requiring mechanical ventilation had a probable viral pathogen. Prodromal, clinical and outcome parameters did not distinguish virus from non-virus illness. PCR was the most sensitive whilst virus culture was the least of virus assays.

Electronic supplementary material

The electronic reference of this article is http://dx.doi.org/10.1007/s00134-006-0202-x. The online full-text version of this article includes electronic supplementary material. This material is available to authorised users and can be accessed by means of the ESM button beneath the abstract or in the structured full-text article. To cite or link to this article you can use the above reference.

Acute exacerbation of chronic bronchitis: expanding short-course therapy

Recent management guidelines for acute exacerbation of chronic bronchitis (AECB) have provided antimicrobial options for different classes of patients according to varying disease severity or risk of treatment failure. In a pivotal, double-blind, double-dummy study comparing azithromycin microspheres (2 g single dose) with the respiratory quinolone levofloxacin (500 mg once daily x 7 days) for the treatment of AECB, the two regimens were equally effective and well tolerated in patients with mild-to-moderate disease (clinical cure rate 93.6% vs. 92.7%, respectively [95% confidence interval (CI) for difference, -3.4, 5.5] and overall bacteriological eradication rate 91.9% vs. 94.4%, respectively (95% CI for difference, -8.8, 3.8). Interestingly, additional post hoc analyses suggest that a single dose of azithromycin also provides comparable clinical efficacy to levofloxacin in patients with a forced expiratory volume in 1 s (FEV1) of less than 70% of the predicted value, a risk factor that would place them in a more severe stratum. These data support azithromycin microspheres as an appropriate option in patients with mild-to-moderate AECB. The potential role of this preparation and other macrolides in patients at higher risk of therapeutic failure requires additional prospective data.

Should patients with acute exacerbation of chronic bronchitis be treated with antibiotics? Advantages of the use of fluoroquinolones

The pathological changes in chronic bronchitis (CB) produce airflow obstruction, reduce the effectiveness of the mucocilliary drainage system and lead to bacterial colonisation of bronchial secretion. The presence of bacteria induces an inflammatory response mediated by leukocytes. There is a direct relationship between the degree of impairment of the mucocilliary drainage system, the density of bacteria in mucus and the number of leukocytes in the sputum. Purulent sputum is a good marker of a high bacterial load. Eventually, if the number of leukocytes is high, their normal activity could decrease the effectiveness of the drainage system, increase the bronchial obstruction and probably damage the lung parenchyma. Whenever the density of bacteria in the bronchial lumen is >or=10(6) CFU/mL, there is a high probability that the degree of inflammatory response will lead to a vicious cycle which in turn tends to sustain the process. This situation can arise during the clinical course of any acute exacerbation of CB, independently of its aetiology, provided the episode is sufficiently severe and/or prolonged. Fluoroquinolones of the third and fourth generation are bactericidal against most microorganisms usually related to acute exacerbations of CB. Their diffusion to bronchial mucus is adequate. When used in short (5-day) treatment they reduce the bacterial load in a higher proportion than is achieved by beta-lactam or macrolide antibiotics given orally. Although the clinical cure rate is similar to that obtained with other antibiotics, the time between exacerbations could be increased.

Role of infection and antimicrobial therapy in acute exacerbations of chronic obstructive pulmonary disease

Over the past several years, the significance of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) in patients with chronic airflow obstruction has become increasingly apparent due to the impact these episodes have on the natural history of disease. It is now known that frequent AECOPD can adversely affect a patient's health-related quality of life and short- and long-term pulmonary function. The economic burden of these episodes is also substantial. AECOPDs represent a local and systemic inflammatory response to both infectious and noninfectious stimuli, but the majority of episodes are likely related to bacterial or viral pathogens. Patients with purulent sputum and multiple symptoms are the most likely to benefit from treatment with antibiotics. Antibiotic choice should be tailored to the individual patient, taking into account the severity of the episode and host factors which might increase the likelihood of treatment failure. Current evidence suggests that therapeutic goals not only include resolution of the acute episode, but also prolonging the time to the next event. In the future, preventing exacerbations will likely become increasingly accepted as an additional therapeutic goal in chronic obstructive pulmonary disease patients.

Telithromycin in the treatment of pneumococcal community-acquired respiratory tract infections: a review

OBJECTIVES

A pooled analysis of 14 Phase III studies was performed to establish the clinical and bacteriologic efficacy of telithromycin 800 mg once daily in the treatment of pneumococcal community-acquired respiratory tract infections (RTIs).

METHODS

Data were examined from 5534 adult/adolescent patients with community-acquired pneumonia (CAP), acute exacerbations of chronic bronchitis (AECB), or acute bacterial sinusitis, who had received telithromycin for 5-10 days or a comparator antibacterial.

RESULTS

Streptococcus pneumoniae was identified in 704/2060 (34.2%) bacteriologically evaluable patients. The respective per-protocol clinical cure rates for telithromycin and comparators were 94.3% and 90.0% (CAP); 81.5% and 78.9% (AECB); 90.1% and 87.5% (acute sinusitis); 92.7% and 87.6% (all indications). Clinical cure rates were 28/34 (82.4%) and 5/7, respectively, for penicillin-resistant infections, and 44/52 (84.6%) and 11/14, respectively, for erythromycin-resistant infections. Of 82 patients with pneumococcal bacteremia, 74 (90.2%) were clinically cured after telithromycin treatment, including 5/7 and 8/10 with penicillin- or erythromycin-resistant strains, respectively. Adverse events considered possibly related to study medication were reported by 1071/4045 (26.5%) telithromycin and 505/1715 (29.4%) comparator recipients. These events were generally of mild/moderate severity, and mainly gastrointestinal in nature.

CONCLUSIONS

As S. pneumoniae is the leading bacterial cause of community-acquired RTIs, and antibacterial resistance is increasing among this species, these findings support the use of telithromycin as first-line therapy in this setting.

COPD exacerbations . 2: aetiology

Exacerbations of COPD are thought to be caused by complex interactions between the host, bacteria, viruses, and environmental pollution. These factors increase the inflammatory burden in the lower airways, overwhelming the protective anti-inflammatory defences leading to tissue damage. Frequent exacerbations are associated with increased morbidity and mortality, a faster decline in lung function, and poorer health status, so prevention or optimal treatment of exacerbations is a global priority. In order to evolve new treatment strategies there has been great interest in the aetiology and pathophysiology of exacerbations, but progress has been hindered by the heterogeneous nature of these episodes, vague definitions of an exacerbation, and poor stratification of known confounding factors when interpreting results. We review how an exacerbation should be defined, its inflammatory basis, and the importance of exacerbations on disease progression. Important aetiologies, with their potential underlying mechanisms, are discussed and the significance of each aetiology is considered.

When will the genomics investment pay off for antibacterial discovery?

Effective solutions to antibacterial resistance are among the key unmet medical needs driving the antibacterial industry. A major thrust in a number of companies is the development of agents with new modes of action in order to bypass the increasing emergence of antibacterial resistance. However, few antibacterials marketed in the last 30 years have novel modes of action. Most recently, genomics and target-based screening technologies have been emphasized as a means to facilitate this and expedite the antibacterial discovery process. And although no new antibacterials have yet been marketed as result of these technologies, genomics has delivered well-validated novel bacterial targets as well as a host of genetic approaches to support the antibacterial discovery process. Likewise, high throughput screening technologies have delivered the capacity to perform robust screenings of large compound collections to identify target inhibitors for lead generation. One of the principal challenges still facing antibacterial discovery is to become proficient at optimizing target inhibitors into broad-spectrum antibacterials with appropriate in vivo properties. Genomics-based technologies clearly have the potential for additional application throughout the discovery process especially in the areas of structural biology and safety assessment.

Susceptibility of Streptococcus pneumoniae to penicillin, azithromycin and telithromycin (PROTEKT 1999–2003)

Isolates of Streptococcus pneumoniae collected over the first 4 years of the PROTEKT study were tested for susceptibility to penicillin, azithromycin and telithromycin. A total of 20,750 isolates were collected from 39 countries. Penicillin non-susceptibility rates were stable over the study period; overall, 21.8% of isolates were resistant. Azithromycin resistance increased from 31.0% in Year 1 to 36.3% in Year 4. Resistance rates for penicillin and azithromycin varied between countries and were highest in France, Spain, South Africa, USA and the Far East. Multidrug resistance in S. pneumoniae did not change significantly over the 4 years, with an overall rate of 38.6%. Telithromycin retained good activity against S. pneumoniae (0.1% of isolates resistant), including multidrug-resistant isolates.

Trends in anti-bacterial resistance among Streptococcus pneumoniae isolated in the USA, 2000–2003: PROTEKT US years 1–3

OBJECTIVES

To determine geographic and temporal trends in anti-bacterial resistance among Streptococcus pneumoniae isolated from patients with respiratory tract infections as part of the PROTEKT US surveillance study (2000-2003).

METHODS

From 2000 to 2003, 31 001 isolates of S. pneumoniae were collected. Anti-bacterial minimum inhibitory concentrations were determined at a central laboratory using the CLSI broth microdilution method. Macrolide resistance genotypes were determined by PCR.

RESULTS

Overall, 29.4, 22.5, 0.9, and 0.02% of S. pneumoniae isolates were resistant to erythromycin, penicillin, levofloxacin, and telithromycin, respectively, with considerable regional variability. Multidrug resistance was stable at approx. 31%. Among macrolide-resistant isolates, mef(A) was the most prevalent resistance gene identified; however, the percentage of isolates with this gene decreased from 68.8% (2000) to 63.9% (2003), while the prevalence of isolates containing both the erm(B) and mef(A) genes increased (2000, 9.7%; 2003, 16.4%). Over 90% of these erm(B)+mef(A)-positive isolates were also resistant to penicillin, tetracycline, or trimethoprim-sulfamethoxazole, while 98.6% were susceptible to levofloxacin and 99.1% were susceptible to telithromycin.

CONCLUSIONS

Penicillin and erythromycin resistance among isolates of S. pneumoniae from the U.S.A. remained high over the 3 years of the study. Telithromycin demonstrated potent in vitro activity against pneumococcal strains.

A review of guidelines for antibacterial use in acute exacerbations of chronic bronchitis

Acute exacerbations of chronic bronchitis (AECB) affect a significant proportion of the adult population worldwide and are associated with a substantial socioeconomic burden. The majority of episodes of AECB are bacterial in aetiology and patients are generally treated empirically with orally administered antibacterial agents. Guidelines for the management of AECB have been developed by a number of national health authorities and international organisations, with the aim of promoting rational selection of antibacterial therapy to minimise the risk of treatment failure and subsequent hospitalisation while containing the development and spread of antibacterial resistance. This paper reviews a number of recently published or updated AECB treatment guidelines, focusing on patient stratification strategies, antibacterial treatment recommendations, and newer antibacterial treatment options, including respiratory fluoroquinolones and the ketolide telithromycin, which have recently been added to a number of national treatment guidelines.

Emergence and spread of Streptococcus pneumoniae with erm(B) and mef(A) resistance

Streptococcus pneumoniae isolates (N = 31,001) were collected from patients with community-acquired respiratory tract infections during the PROTEKT US surveillance study (2000–2003). While the macrolide (erythromycin) resistance rate remained stable at ≈29%, the prevalence of resistant isolates containing both erm(B) and mef(A) increased from 9.7% in year 1 to 16.4% in year 3, with substantial regional variability. Almost all (99.2%) dual erm(B)+mef(A) macrolide-resistant isolates exhibited multidrug resistance, whereas 98.6% and 99.0% were levofloxacin- and telithromycin-susceptible, respectively. These strains were most commonly isolated from the ear or middle-ear fluid of children. Of 152 representative erm(B)+mef(A) isolates, >90% were clonally related to the multidrug-resistant international Taiwan^19F-14 clonal complex 271 (CC271). Of 366 erm(B)+mef(A) isolates from the PROTEKT global study (1999–2003), 83.3% were CC271, with the highest prevalence seen in South Africa, South Korea, and the United States. This study confirms the increasing global emergence and rapidly increasing US prevalence of this multidrug-resistant pneumococcal clone.

Treatment of acute exacerbation of severe-to-very severe COPD with azithromycin in patients vaccinated against Streptococcus pneumoniae

Sixty-five consecutive eligible adult patients, who were treated as outpatients for stable severe-to-very severe COPD, were enrolled in the study. All of them received 23-valent pneumococcal capsular polysaccharide vaccine intramuscularly. Patients were seen monthly, as well as whenever they had symptoms suggestive of an exacerbation, at our outpatient clinic. Eighteen out of 65 patients suffered from acute exacerbation (AECOPD). Three of these patients presented two episodes of AECOPD. Patients with an acute exacerbation of COPD received azithromycin 500 mg/day once daily for 3 days and a short course of oral prednisolone 25 mg/die. In 16 cases, a single species was isolated, while in the remaining 5 cases at least two species were recovered. Clinical cure or improvement at the end of therapy (3-5 days post-therapy) was reported in 17 episodes of AECOPD with no relapse at the late post-therapy (10-14 days after the completion of treatment). Bacteriologic eradication or presumptive eradication rates at the end of therapy were 86% (24 out of 28 isolates). Azithromycin eradicated all isolates of Haemophilus influenzae, Moraxella catarrhalis, H. parainfluenzae, Klebsiella pneumoniae, and Klebsiella spp. isolated at baseline. Eradication of Sta aureus occurred in 1 of 3 isolates whereas azithromycin was unable to eradicate Pseudomonas aeruginosa isolates. Our data seem to indicate that pneumococcal vaccination reduces the possibility that an AECOPD is caused by Streptococcus pneumoniae. This finding allows the use of antibiotics such as azithromycin, which, otherwise, should be avoided because of resistances.

Sputum color as a marker of acute bacterial exacerbations of chronic obstructive pulmonary disease

We analyzed 795 sputa from 315 patients (233 males, mean age 69.3+/-8.8 years, mean number of exacerbations 2.52/patient) with acute exacerbations of moderate-to-severe chronic obstructive pulmonary disease (COPD) (mean steady-state FEV1 42.5+/-7.8% of predicted). 581/795 sputa were considered adequate. Sputum was analyzed by a quali-quantitative colorimetric scale allowing both color distinction and color degree of intensity. Quantitative culture was then performed (threshold: >10(6)CFU/mL). Samples were distinguished in mucoid (145) and purulent (436) sputa. Absence of bacterial growth was observed in 22% and 5% of mucoid and purulent sputa, respectively. Among mucoid sputa, Gram positive bacterial growth occurred more commonly compared to Gram negative and Pseudomonas aeruginosa/Enterobacteriaceae (56%, 24%, 20%, respectively). In purulent sputa, Gram positives were found in 38% of cases, Gram negatives in 38%, and P. aeruginosa/Enterobacteriaceae in 24%. We evaluated whether functional impairment (FEV1) orientates as to the infectious etiology of exacerbations. Significant differences were observed in the distribution of pathogens. Gram negative and P. aeruginosa/Enterobacteriaceae were isolated more frequently in the sputum when FEV1 was <35%. Our study indicates that purulent sputum is strongly associated with bacterial growth in COPD exacerbations. Deepening sputum color (from yellowish to brownish) was associated with increased yield of Gram negative and P. aeruginosa/Enterobacteriaceae.

Gemifloxacin: a new, potent fluoroquinolone for the therapy of lower respiratory tract infections

The fluoroquinolone gemifloxacin has recently been approved for the treatment of acute bacterial exacerbations of chronic bronchitis and mild community acquired pneumonia, including that caused by multidrug-resistant Streptococcus pneumoniae. Owing to the increasing prevalence of multidrug-resistant S. pneumoniae, as well as resistance to other common pathogens of acute bacterial exacerbations of chronic bronchitis and community acquired pneumonia, it is important to have new, potent antimicrobial agents for the treatment of these infections. Gemifloxacin is the most potent antimicrobial agent in vitro for S. pneumoniae, and has excellent activity against the other key pathogens of acute bacterial exacerbations of chronic bronchitis and community acquired pneumonia, including the atypical microorganisms. The clinical trial outcomes of several studies that have evaluated gemifloxacin show a range of superior clinical or bacteriologic outcomes against several current antimicrobials, including levofloxacin, clarithromycin, trovafloxacin and ceftriaxone. The safety profile of gemifloxacin is similar to that of approved agents to treat acute bacterial exacerbations of chronic bronchitis and community acquired pneumonia, with a low discontinuation rate of 2.2%. A nonphototoxic rash (usually a mild, maculopapular rash) was observed in 2.8% of patients in clinical studies.

Telithromycin for the treatment of acute exacerbations of chronic bronchitis

Pooled data from three randomized, double-blind, multi- centre studies evaluated the efficacy and tolerability of telithromycin 800 mg once daily for 5 days vs. standard comparators (10-day amoxicillin-clavulanate 500/125 mg three times daily, clarithromycin 500 mg or cefuroxime axetil 500 mg twice daily) in the outpatient treatment for acute exacerbations of chronic bronchitis. Per-protocol clinical cure rates at post-therapy/test of cure (days 17-24) were 86.0 and 85.8% for telithromycin and comparators, respectively, and 79.1 and 78.7%, respectively, at late post-therapy (days 31-36). Clinical cure rates were comparable for patients at increased risk, including those of > or =65 years and those with severe infection or significant airway obstruction (telithromycin, > or =77.1%; comparators, > or =75.0%). Telithromycin was well tolerated. Most adverse events considered possibly related to study medication were gastrointestinal and of mild intensity. In conclusion, 5-day telithromycin therapy is as effective and well tolerated as 10-day treatment with standard comparators.

Antimicrobial susceptibility of community-acquired respiratory tract pathogens in the UK during 2002/3 determined locally and centrally by BSAC methods

OBJECTIVES

To determine the antimicrobial susceptibility of Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae causing community-acquired lower respiratory tract infection in the UK during 2002/2003 and to compare susceptibilities determined locally by disc diffusion with agar dilution MICs determined at a central laboratory.

METHODS

H. influenzae, M. catarrhalis and S. pneumoniae were isolated in 30 laboratories and susceptibility determined locally by the BSAC standardized disc diffusion method. At a central laboratory, isolates were re-identified, tested for beta-lactamase production (H. influenzae and M. catarrhalis only) and MICs determined using the BSAC agar dilution method.

RESULTS

Five hundred and eighty-one H. influenzae, 269 M. catarrhalis and 519 S. pneumoniae were collected. Over 93% of M. catarrhalis and nearly 15% of H. influenzae were beta-lactamase positive rendering these sub-populations resistant to aminopenicillins. Overall, the antibacterial susceptibility rates for the isolates were high. However, macrolides showed poor activity against H. influenzae (0.86-1.38% susceptible by disc or MIC methods) and, compared with other antimicrobials, against S. pneumoniae (approximately 88% susceptible). Between 84% and 95% of H. influenzae, M. catarrhalis and S. pneumoniae were susceptible to cefuroxime but all isolates were susceptible to cefotaxime. Eighty-five percent of H. influenzae were susceptible to trimethoprim. The fluoroquinolones were very active against the isolates, with moxifloxacin showing lower MICs than levofloxacin against S. pneumoniae. Susceptibility determined locally by disc diffusion was in general agreement with that determined centrally by agar dilution MIC testing. However, there was one inconsistency with H. influenzae where disc diffusion indicated 22.9% and 46.8% resistance to clarithromycin and erythromycin, respectively but by MIC, only 0.9% and 6.9% were resistant, respectively.

CONCLUSIONS

Rates of resistance within community-acquired respiratory tract isolates were relatively low in the UK, in agreement with other studies. Moxifloxacin was the only antibacterial with over 99% isolates susceptible for each of the three pathogens investigated where breakpoints are available. The comparison between disc susceptibility testing and MIC determination using BSAC methods indicated generally good correlation but has highlighted a methodological problem with macrolides against H. influenzae in particular.

PROTEKT 1999–2000: a multicentre study of the antimicrobial susceptibility of respiratory tract pathogens in Japan

DESIGN

A six-centre study in Japan during the winter of 1999-2000 assessed the in vitro activity of >20 antimicrobial agents against the common respiratory pathogens Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis. The minimum inhibitory concentrations (MIC) of each antimicrobial was determined against these isolates using National Committee for Clinical Laboratory Standards (NCCLS) methodology.

RESULTS

Among S. pneumoniae isolates, 44.5% were penicillin resistant. The macrolide resistance rate was 77.9% with 90.5% of penicillin-resistant strains also being macrolide resistant. Resistance mechanisms in macrolide-resistant isolates were identified as mef(A) or erm(B) in 42.5% and 52.5%, respectively. Of the fluoroquinolone-resistant isolates (1.3%), most were also penicillin and macrolide resistant. All strains were inhibited by telithromycin at <or=1mg/L. Among S. pyogenes isolates, erythromycin resistance was 17.5% overall but showed considerable variation among the six centres. For H. influenzae, 8.5% produced beta-lactamase and a single beta-lactamase-negative, ampicillin-resistant isolate (0.36%) was obtained, and there was no fluoroquinolone resistance. All isolates were susceptible to telithromycin. Most antimicrobials showed good activity against M. catarrhalis, although 96.7% were beta-lactamase positive.

CONCLUSION

The prevalence of antimicrobial resistance to macrolides, penicillin and the fluoroquinolones among the common respiratory pathogens is high in Japan.

Management of respiratory infections in the elderly

Respiratory infections are common at all ages but are particularly sinister among the elderly because of the fragility and chronic comorbidity associated with this age group. The three types of respiratory infection in the elderly are community-acquired pneumonia, acute exacerbation of chronic obstructive pulmonary disease and nonpneumonic respiratory tract infection. The etiology of these three types of infection includes classic bacteria, atypical pathogens and respiratory viruses. The relative frequency of each of the etiological groups as the causative agent of the infection varies significantly among these types of infection, but in all three types a significant proportion of infections involves more than one pathogen. The causative agent of respiratory infection in the elderly cannot be determined on the basis of clinical manifestation or the results of routine imaging procedures or laboratory tests. Thus, initial antibiotic therapy in these patients should be empiric, based on accepted guidelines. In recent years, the antipneumococcal fluoroquinolones have gained in stature as one of the best options to treat these infections. Pneumococcal and influenza vaccinations can reduce morbidity and mortality from respiratory infections in the elderly, so it is important that all elderly individuals are vaccinated through a structured program in the framework of primary care. The economic impact of respiratory infections in the elderly is primarily associated with the requirement for hospitalization in many of the cases. Any action that can reduce hospitalization rates has important economic ramifications. In light of the difficulty in reaching an early etiologic diagnosis in respiratory infections, it is essential to invest in the development of a compact diagnostic kit for the early stages of the disease, which could change reality in this important area of medicine.

A randomized, double-blind study comparing 5 days oral gemifloxacin with 7 days oral levofloxacin in patients with acute exacerbation of chronic bronchitis

OBJECTIVE

To demonstrate that 5 days of treatment with a new fluoroquinolone, gemifloxacin, is at least as effective as 7 days of treatment with levofloxacin in adult patients with acute exacerbation of chronic bronchitis (AECB).

DESIGN

Randomized, double-blind, double dummy, multicentre, parallel group study

SETTING

Sixty different medical centers in US, UK and Germany.

MATERIAL AND METHODS

A total of 360 adults (>40 years of age) with AECB were randomly assigned to receive gemifloxacin 320 mg once daily for 5 days or levofloxacin 500mg once daily for 7 days. The primary efficacy parameter was a clinical response at follow-up (Days 14-21).

RESULTS

In total, 335/360 patients completed the study (93.1%). Seven patients receiving gemifloxacin withdrew from the study compared to 18 patients receiving levofloxacin; this difference was statistically significant (Fisher's exact test: p=0.02). In the intent-to-treat (ITT) population, the clinical success rate at follow-up (Days 14-21) was 85.2% (155/182) with gemifloxacin and 78.1% (139/178) with levofloxacin. Clinical success rate in the per-protocol (PP) population was 88.2% (134/152) with gemifloxacin and 85.1% (126/148) with levofloxacin. At long-term follow-up (Days 28-35), the clinical success rates in the PP population were 83.7% (123/147) with gemifloxacin and 78.4% (109/139) with levofloxacin. The difference in success rates was 5.26% (95% CI: -3.83, 14.34).

CONCLUSION

The clinical efficacy of gemifloxacin 320 mg once daily for 5 days in AECB was at least as good as levofloxacin 500 mg once daily for 7 days. Fewer withdrawals and superior clinical efficacy at long-term follow-up were also seen with gemifloxacin.

Clinical Predictors of Bacterial Involvement in Exacerbations of Chronic Obstructive Pulmonary Disease

BACKGROUND

The wide use of antibiotics for treatment of exacerbations of chronic obstructive pulmonary disease (COPD) lacks evidence. The efficacy is debatable, and bacterial involvement in exacerbation is difficult to verify. The aim of this prospective study was to identify factors that can help to estimate the probability that a microorganism is involved in exacerbation of COPD and, therefore, predict the success of antibiotic treatment.

METHODS

Clinical data and sputum samples were obtained from 116 patients during exacerbation of COPD. Bacterial infection was defined by the abundant presence of >or=1 potential pathological microorganism in relation to the normal flora in sputum.

RESULTS

Of 116 exacerbations, 22 (19%) had bacterial involvement. The combination of a negative result of a sputum Gram stain, a relevant nonclinical decrease in lung function (compared with baseline measurements), and occurrence of <2 exacerbations in the previous year were 100% predictive of a nonbacterial origin of the exacerbation. The presence of all 3 of these clinical characteristics yielded a positive predictive value of 67% for a bacterial exacerbation.

CONCLUSIONS

Patients presenting with an exacerbation who have a negative result of sputum Gram stain, do not have a clinically relevant decrease in lung function, and have experienced <2 exacerbations of COPD in the previous year do not require antibiotic treatment [corrected]. A treatment protocol taking into account these variables might lead to a 5%-24% reduction in unnecessary treatment with antibiotics, depending on actual prescription rates.

Therapeutic implications of macrolide resistance in pneumococcal community-acquired lower respiratory tract infections

Macrolide anti-bacterials are widely used for the empirical treatment of lower respiratory tract infections (RTIs) due to their activity against Streptococcus pneumoniae and other common respiratory pathogens and good safety/tolerability profile. However, the prevalence of macrolide resistance, particularly pneumococcal macrolide resistance, is increasing all around the world. The mechanisms underlying macrolide resistance include efflux pump, methylase activity and, less commonly, ribosomal mutation, which produce differing levels of resistance. Growth in macrolide resistance has been linked to the increased use of these agents, and several risk factors for the development of resistance have been identified. There are emerging data to suggest that in vitro macrolide resistance may increase the likelihood of treatment failure in patients with lower RTIs. However, at present, treatment failure is rare and randomised; intervention-based trials investigating the impact of anti-bacterial resistance on clinical outcomes are lacking. Strategies to promote appropriate use of macrolides and other anti-bacterials are needed, both to maximise therapeutic impact and to minimise the development of resistance. Furthermore, there is a need for alternative anti-bacterial agents which have high efficacy against respiratory pathogens (including resistant strains) and a low potential to induce resistance.

Five-day moxifloxacin therapy compared with 7-day co-amoxiclav therapy for the treatment of acute exacerbation of chronic bronchitis

In this randomized, non-blinded study, the efficacy and safety of a 5-day course of moxifloxacin (one 400 mg tablet daily) was compared with that of co-amoxiclav (one 625 mg tablet every 8h) for 7 days, for the treatment of acute exacerbations of chronic bronchitis (AECB). A total of 162 patients with clear signs of an acute exacerbation of chronic bronchitis were enrolled. Of these, 153 could be studied. Seventy-nine patients were randomized in the moxifloxacin arm and 74 in the co-amoxiclav arm of the study. The primary efficacy parameter was clinical response at 14 days in the evaluable population. A clinical success was classified as resolution or improvement of symptoms. Variables used to assess clinical response included wheeze, cough, dyspnoea, sputum volume, rales and ronchi. The success rate in the moxifloxacin group was 88.6% (70 of 79) and that for co-amoxiclav group was 89.2% (66 of 74). At follow-up (28-35 days post-treatment), the continued clinical cure rates were 90.0% (63 of 70) for moxifloxacin and 89.4% (59 of 66) for co-amoxiclav. No significant differences were detected between the two groups. A total of 78 pathogenic bacteria were isolated from the sputum samples of the patients, with Moraxella catarrhalis, Haemophilus influenzae and Streptococcus pneumoniae being the most frequently isolated pathogens. The eradication rate at 14 days in the valid patients was similar for both groups, 90.9% (20 of 22) for the moxifloxacin group and 90.0% (18 of 20) for the co-amoxiclav group. Both drugs were well tolerated with no differences in the drug-related adverse effects or the patients withdrawing because of an adverse event. These results and the good spectrum of antibacterial activity make moxifloxacin a promising and also safe alternative for the empirical treatment of AECB.

Acute bronchitis: state of the art diagnosis and therapy

In managing acute bronchitis, pneumonia or an exacerbation of underlying chronic bronchitis should be excluded. Simple bronchitis is best treated symptomatically while an exacerbation of chronic bronchitis can be treated with antibiotics. Broad spectrum antibiotics are appropriate in selected patients.

Prevention and management of antibacterial resistance for primary care patients with respiratory tract infections

This review examines the problem of increasing antibacterial resistance among the pathogens commonly associated with community-acquired respiratory tract infections, particularly Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. The increases in morbidity, mortality, and treatment cost associated with increased resistance to available antibiotics are challenging prescribers to find more effective therapeutic strategies. A MEDLINE search of the literature from 1966 to the present was performed to seek data relevant to the issue of resistance, especially the negative effects on patient outcomes and costs of therapy. Several observations and conclusions emerged. Data are lacking on local resistance patterns, broad-spectrum agents are overprescribed when narrower-spectrum choices would be more appropriate, a need exists for educational programs to encourage restricting drug use and changing prescribing habits, and there is a need for new antibiotic choices. The best antibiotic options are agents with a tailored spectrum of activity that are targeted at particular respiratory tract pathogens and have low potential to select for resistant organisms.

Ketolides: a new class of antibacterial agents for treatment of community-acquired respiratory tract infections in a primary care setting

Pathogens implicated in community-acquired respiratory tract infections are becoming increasingly resistant to anti-bacterial therapies. Thus, there is an urgent need for new agents with activity against current resistant respiratory tract pathogens and a low potential to select for resistance or induce cross-resistance to existing antibacterial agents. Telithromycin, the first ketolide antibacterial agent to undergo clinical development, has enhanced binding to bacterial ribosomal RNA. Through its unique structure, telithromycin retains activity against resistant respiratory pathogens and has shown high efficacy in the treatment of respiratory tract infections. On the basis of phase 3 clinical trial experience, telithromycin appears safe and well tolerated across various patient populations, including high-risk groups.

Oral telithromycin 800 mg once daily for 5 days versus cefuroxime axetil 500 mg twice daily for 10 days in adults with acute exacerbations of chronic bronchitis

The efficacy and safety of a 5-day regimen of 800 mg telithromycin once daily was compared with a standard 10-day regimen of 500 mg cefuroxime axetil twice daily in a multicentre, randomized, double-blind, parallel-group trial involving 376 patients with acute exacerbations of chronic bronchitis (AECB). In clinically evaluable patients (n = 282), post-therapy clinical cure rates were 86.4% with telithromycin and 83.1% with cefuroxime axetil. In bacteriologically evaluable patients (n = 53), eradication or presumed eradication of the pathogen was achieved in 76.0% and 78.6% of telithromycin and cefuroxime axetil patients, respectively. Adverse events were mostly mild; the most common were diarrhoea (12.8% versus 11.8%) and nausea (8.9% versus 3.2%) in telithromycin and cefuroxime axetil patients, respectively. The 5-day regimen of 800 mg telithromycin once daily was similar in efficacy and equally well tolerated as a 10-day regimen of 500 mg cefuroxime axetil twice daily in adults with AECB.

Oral gemifloxacin once daily for 5 days compared with sequential therapy with i.v. ceftriaxone/oral cefuroxime (maximum of 10 days) in the treatment of hospitalized patients with acute exacerbations of chronic bronchitis

In a randomized, open-label, controlled, multicentre study, the clinical and bacteriological efficacy, safety and tolerability of oral gemifloxacin (320 mg once daily, 5 days) was compared with sequential intravenous (i.v.) ceftriaxone (1 g once daily, maximum 3 days) followed by oral cefuroxime axetil (500 mg twice daily, maximum 7 days) in adult hospitalized patients with acute exacerbations of chronic bronchitis (AECB) (n = 274). The clinical success rates at follow-up (21-28 days post-therapy) in the clinical per-protocol population (the primary endpoint) were 86.8% (105/121) for gemifloxacin vs. 81.3% (91/112) for ceftriaxone/cefuroxime (treatment difference = 5.5,95% CI -3.9,14.9). The corresponding clinical results in the clinical intention-to-treat (ITT) population were 82.6% (114/138) vs. 72.1% (98/136), respectively (treatment difference = 10.5,95% CI 0.7, 20.4).Thus, gemifloxacin had significantly higher clinical success rates than ceftriaxone/cefuroxime. The median time to discharge was 9 days in the gemifloxacin group vs. 11 days in the ceftriaxone/cefuroxime group (P = 0.04, Wilcoxon test). At follow-up, 120/138 (87.0%) gemifloxacin-treated patients had been discharged from hospital, compared with 111/136 (81.6%) ceftriaxone/cefuroxime-treated patients in the clinical ITT population. Both treatments were generally well tolerated and there was no significant difference between the treatment groups in the incidence or type of adverse events reported. A 5-day course of oral gemifloxacin was shown by this study to be at least equivalent to sequential i.v. ceftriaxone/cefuroxime axetil (for up to 10 days) in patients with AECB who require hospital treatment.

Randomised double-blind comparison of oral gatifloxacin and co-amoxiclav for acute exacerbation of chronic Bronchitis

Antimicrobial therapy can have a significant impact in the treatment of acute infectious exacerbations in patients with chronic bronchitis, in whom repeated episodes are common. The aim of this randomised, double-blind, double-dummy, parallel group study was to compare the efficacy and safety of oral gatifloxacin (200 and 400 mg once daily) administered for 5 days with co-amoxiclav (500 mg amoxicillin/125 mg clavulanic acid t.i.d.) administered for 10 days in 414 adult patients with acute exacerbation of chronic bronchitis. Overall clinical response rates (cure plus improvement) were 86.2%, 79.4% and 81.7% in the gatifloxacin 200 mg, gatifloxacin 400 mg and co-amoxiclav groups, respectively, and the equivalence hypothesis used for statistical analysis showed equivalent efficacy for both gatifloxacin 200 and 400 mg compared to co-amoxiclav. The same was true for rates of bacterial response, with eradication or presumed eradication of causative pathogens achieved in 87.5%, 87.3% and 79.1% of cases in the gatifloxacin 200 mg, gatifloxacin 400 mg and co-amoxiclav groups, respectively. All treatments were well tolerated, with the nature and frequency of treatment-related adverse events similar in all groups. The results of the study show that gatifloxacin is a safe and effective agent for the treatment of patients with chronic bronchitis experiencing an acute infectious exacerbation.

Descompensaciones respiratorias en la enfermedad pulmonar obstructiva crónica

La descompensación en la enfermedad pulmonar obstructiva crónica (EPOC) se define como el agravamiento, en general rápido y reversible, de la situación respiratoria en un paciente con EPOC. Estos trastornos son secundarios a trastornos sobreañadidos que requieren un tratamiento específico (neumopatías infecciosas, embolias pulmonares, neumotórax, insuficiencia cardíaca izquierda, errores terapéuticos, etc.) o a exacerbaciones de los fenómenos inflamatorios bronquiales y de los síntomas crónicos (broncorrea, tos, disnea). Su gravedad es variable y oscila entre las formas bien toleradas que pueden tratarse de manera ambulatoria con un coste escaso y las dificultades respiratorias agudas que precisan reanimación inmediata. La utilización razonada de antibióticos, broncodilatadores en dosis altas, corticoides, oxígeno y ventilación asistida (casi siempre «no invasiva») ha mejorado su pronóstico, que sigue siendo mediocre cuando la descompensación se superpone a una EPOC evolucionada.

An open-label, randomized, multicenter, comparative study of the efficacy and safety of 7 days of treatment with clarithromycin extended-release tablets versus clarithromycin immediate-release tablets for the treatment of patients with acute bacterial exacerbation of chronic bronchitis

OBJECTIVE

The aim of this study was to compare the efficacy and safety of clarithromycin extended-release (ER) tablets and immediate-release (IR) tablets.

METHODS

This was a Phase III, open-label, randomized, multicenter, comparative study in ambulatory patients with a diagnosis of acute exacerbation of chronic bronchitis (AECB). Eligible patients were randomized 1:1 to receive either 1 clarithromycin ER 500-mg tablet QD for 7 days or 1 clarithromycin IR 250-mg tablet BID for 7 days. Clinical and bacteriologic responses were assessed within 48 hours after the last dose of study drug and at a test-of-cure visit 21 +/- 2 days posttreatment.

RESULTS

Of 233 patients randomized, 162 (86/117 [73.5%] in the ER group and 76/115 [66.1%] in the IR group) completed the study protocol. Compliance did not differ significantly between the treatment groups; however, significantly fewer patients in the ER group reported missing doses of study medication than in the IR group (7/118 [5.9%] vs 16/115 [13.9%]; P = 0.04). The clinical cure rates for the clarithromycin ER and IR groups were 81.0% (68/84) and 82.1% (64/78) and the clinical success (clinical cure plus clinical improvement) rates were 94.0% [79/84] and 89.7% [70/78], respectively. There were insufficient data for analysis of bacteriologic efficacy. However, bacteria were eradicated or presumed eradicated in 71.4% (10/14) and 79.2% (19/24) of patients in the ER and IR groups, respectively. The number of adverse events (AEs) considered to be possibly or probably related to study drug (23.4% [52/222] of patients receiving clarithromycin ER and 24.4% [43/176] of patients receiving clarithromycin IR) was similar between groups, as was the severity of these events (94.2% [49/52] in the ER group classified as mild or moderate vs 93.0% [40/43] in the IR group). Overall, the most commonly reported AEs were diarrhea, nausea, abdominal pain, headache, and taste disturbance.

CONCLUSION

Clarithromycin ER 500-mg tablets QD for 7 days were as effective and well tolerated as clarithromycin IR 250-mg tablets BID for 7 days in treating adults with AECB.

Telithromycin is as effective as amoxicillin/clavulanate in acute exacerbations of chronic bronchitis

This randomized, double-blind study evaluated the efficacy and safety of a short, 5-day course of telithromycin, a new ketolide antibacterial, compared with a standard 10-day course of amoxicillin/clavulanate, in the treatment of acute exacerbations of chronic bronchitis (AECB). The study enrolled 325 adult patients with AECB and a history of chronic obstructive pulmonary disease (COPD). Patients received either telithromycin 800 mg once daily (qd) for 5 days (followed by placebo for 5 days) or amoxicillin/clavulanate 500/125 mg three times daily (tid) for 10 days. Clinical cure rates for telithromycin post-therapy (Days 17-21, test-of-cure) and late post-therapy (Days 31-36) were 86.1 and 78.1%, respectively; 82.1 and 75.0% for amoxicillin/clavulanate. Excellent clinical cure rates were also observed for high-risk patients. Bacteriologic outcome was satisfactory for 69.2% of telithromycin recipients vs 70.0% for amoxicillin/clavulanate recipients. Both treatments were generally well tolerated, although the frequency of drug-related adverse events was almost two-fold higher for amoxicillin/clavulanate (25.0 vs. 13.1%). Thus, a 5-day course of telithromycin 800 mg qd is an effective and well-tolerated alternative to a standard 10-day course of amoxicillin/clavulanate 500/125 mg tid for first-line empiric treatment of AECB in adults with COPD.

Gatifloxacin phase IV surveillance trial (TeqCES study) utilizing 5000 primary care physician practices: report of pathogens isolated and susceptibility patterns in community-acquired respiratory tract infections

Recently FDA-approved fluoroquinolones like gatifloxacin possess enhanced activity against Gram-positive pathogens such as Streptococcus pneumoniae. However, experience with adverse events among previously used fluoroquinolones has led to expanded post-marketing investigations of clinical efficacy and safety. An open-label gatifloxacin trial was initiated in early 2000, using 2795 (>15000 enrolled cases) primary care providers for treatment of community-acquired respiratory tract infections (CARTI) such as community-acquired pneumonia (CAP), acute bacterial exacerbation of chronic bronchitis (ABECB), acute sinusitis. Microbiology specimens and sputum slides were referred to a reference laboratory, pathogens identified and reference antimicrobial susceptibility tests performed. Results were classified by infection site, geographic census region and patient profile/demographics. The most frequent pathogens were: for CAP (n = 384)-S. pneumoniae (37%) > Hemophilus influenzae (31%) > Moraxella catarrhalis (13%); for ABECB (528)-H. influenzae (37%) > M. catarrhalis (26%) > S. pneumoniae (17%); and for sinusitis (2691)-M. catarrhalis (29%) > H. influenzae (24%) > S. pneumoniae (17%). H. parainfluenzae (ABECB) and S. aureus (sinusitis) were also commonly isolated. CAP S. pneumoniae isolates had significantly less high-level resistance (5% at > or =2 micro g/ml) than those isolates from ABECB or sinusitis (13-15%). United States census zone differences in S. pneumoniae resistance were identified (greatest in West or East South Central, South Atlantic). S. pneumoniae macrolide resistance was high (23-33%) and H. influenzae clarithromycin susceptibility was only 56-62%. beta-lactamase rates in H. influenzae and M. catarrhalis were 21-29% and 88-92%, respectively. Only one S. pneumoniae was not susceptible to gatifloxacin, and this new fluoroquinolone was fourfold more potent than levofloxacin (MIC(50,) 0.25 vs. 1 micro g/ml). This Phase IV surveillance trial (TeqCES) confirmed the clinical importance of S. pneumoniae, H. influenzae and M. catarrhalis in CARTI, and high fluoroquinolone potency/spectrum (>97% susceptible). beta-lactams and macrolides continue to be compromised by increasing resistances in pathogens isolated in these monitored primary care settings.

Open-label, randomized comparison of the efficacy and tolerability of clarithromycin, levofloxacin, and cefuroxime axetil in the treatment of adults with acute bacterial exacerbations of chronic bronchitis

BACKGROUND

In the absence of a confirmed pathogen, empiric antimicrobial treatment of patients with acute exacerbations of chronic bronchitis and acute bacterial exacerbations of chronic bronchitis (ABECB) is accepted as standard practice and recommended in treatment guidelines.

OBJECTIVE

This study compared the efficacy and tolerability of a 10-day course of 3 antimicrobial regimens commonly used to treat adults with ABECB.

METHODS

This prospective, open-label, randomized study assessed clarithromycin 500 mg twice daily, levofloxacin 500 mg once daily, and cefuroxime axetil 250 mg twice daily, each administered for 10 days with food, in patients with ABECB. Efficacy was determined on the basis of the clinical response to treatment and need for hospitalization and/or further antimicrobial therapy.

RESULTS

A total of 283 patients (150 men, 133 women) with a mean age of 55 years (range, 29 to 86 years) were randomized to receive clarithromycin (n = 97), levofloxacin (n = 94), or cefuroxime axetil (n = 92). Of 262 clinically assessable patients, clinical cure or improvement occurred in 87.9% (80/91) of those treated with clarithromycin, 87.4% (76/87) of those treated with levofloxacin, and 79.8% (67/84) of those treated with cefuroxime axetil. Eight (8.8%) clarithromycin-treated patients, 6 (6.9%) levofloxacin-treated patients, and 12 (14.3%) cefuroxime axetil-treated patients required a change in antimicrobial therapy to achieve clinical cure/improvement; between-group differences were not significant. No patients treated with clarithromycin required hospitalization for further antimicrobial treatment, compared with 3.4% (3/87) of levofloxacin-treated and 3.6% (3/84) of cefuroxime axetil-treated patients (P = NS). A total of 6.2% (6/97) of clarithromycin-treated patients were prematurely discontinued from treatment due to adverse events, compared with 7.4% (7/94) and 8.7% (8/92) of levofloxacin- and cefuroxime axetil-treated patients, respectively.

CONCLUSION

A high rate of clinical efficacy and tolerability was observed in this population of patients with ABECB treated with clarithromycin 500 mg twice daily, levofloxacin 500 mg once daily, or cefuroxime axetil 250 mg twice daily for 10 days.

Streptococcus pneumoniae as an agent of nosocomial infection: treatment in the era of penicillin-resistant strains

Streptococcus pneumoniae is a well-known agent of community-acquired infections such as sinusitis, otitis media, pneumonia, bacterial meningitis, bacteremia and acute exacerbations of chronic bronchitis. However, the role of S. pneumoniae as a cause of nosocomial infections of respiratory tract, bloodstream and central nervous system is more and more recognized, primarily in high-risk patients with depression of their immune function. Therapy of pneumococcal infections is made difficult by the emergence and spread of bacterial resistance to penicillin and other beta-lactams as well as to a number of antimicrobials such as macrolides, chloramphenicol, tetracyclines and sulfonamides. This epidemiological situation is a cause for concern world-wide, but it primarily affects some European countries, North America, South Africa and the Far East. The main consequence on therapeutic grounds is that in severe infections such as bacterial meningitis, the addition of vancomycin to a third-generation cephalosporin is advisable while awaiting laboratory test results, even in areas with low prevalence of penicillin-resistant pneumococci. However, a beta-lactam agent can also be a valid choice in the presence of potentially lethal infections such as pneumonia or in the case of penicillin intermediately resistant isolates. In recent years, new alternative molecules have been introduced into clinical practice for therapy of infections caused by penicillin-resistant pneumococci. In both in vivo and in vitro studies, drugs of the classes of fluoroquinolones (levofloxacin, moxifloxacin, gatifloxacin), streptogramins (quinupristin/dalfopristin) and oxazolidinones (linezolid) have shown good microbiologic and clinical efficacy against penicillin-resistant pneumococci. In this era of world-wide spread of penicillin-resistant pneumococci, use of polysaccaride or conjugated vaccines is highly recommended.

Antibiotics

This chapter discusses the bacterial pathogens that cause infective exacerbations, trials of antimicrobial therapy, individual antimicrobial agents, and guidelines for their use in the treatment of both asthma and chronic obstructive pulmonary disease (COPD). The relationship between respiratory tract infection, especially viral infection, and exacerbations of airway diseases is very well established. However, research is required to find new ways to distinguish between the colonization and infective exacerbations of COPD to gain a better understanding of the role of infection in the disease. With advances in molecular biology, the antigenic structures of bacteria and the evaluation of the antibody response to antigens can become the basis for identifying an acute exacerbation of COPD (AECB). Most clinical trials of antibiotics were performed for licensing, and patients with pathogens resistant to different antimicrobials were excluded. Future studies of new antimicrobials should examine clinical efficacy more stringently based on a classification system that would help select patients most likely to benefit from an antibiotic. These studies should also include well-defined prospective economic analyses and quality-of-life assessment to ascertain the cost utility of the antibiotic in question.

Acute exacerbations of chronic bronchitis: a pharmacoeconomic review of antibacterial use

Chronic bronchitis is a common problem affecting a large proportion of the adult population. People with chronic bronchitis are subject to recurrent attacks of bronchial inflammation called acute exacerbations of chronic bronchitis (AECBs). In patients with AECBs, symptoms may worsen due to a bacterial infection; the exacerbation is then known as an acute bacterial exacerbation of chronic bronchitis (ABECB). ABECBs are thought to be controllable through the use of antibacterial agents. In this paper we review current evidence on the cost of chronic bronchitis and AECBs, the cost effectiveness of antibacterials in the management of ABECB, and the factors that may affect the cost-effectiveness of antibacterials in the management of ABECB. We find that the number of economic evaluations conducted in this area is small. Of the few economic evaluations that have been conducted there has been only one prospective economic evaluation based on a clinical trial. The remainder are simple decision analysis-based modelling studies or retrospective database studies. Our principle findings are as follows: a key factor affecting the cost-effective use of antibacterials in the management of ABECB is the definitive diagnosis of the condition. Unfortunately, diagnosing a bacterial cause of an AECB is difficult, which presents problems in ensuring that antibacterials are not prescribed unnecessarily;current evidence suggests but does not prove that use of more effective but more costly first-line antibacterials may be relatively cost effective and may minimise overall expenditure by reducing the high costs associated with treatment failure;chronic bronchitis and AECB have a significant and negative physical and psychological effect on health-related quality of life. In conclusion, the small number of economic evaluations conducted in this area, coupled with the nature of the design of these studies, precludes a definitive statement recommending which specific antibacterial should be preferred on cost-effectiveness grounds for the management of ABECB. On the basis of our findings we suggest some topics for further research.

Optimizing economic outcomes in acute exacerbations of chronic bronchitis

The treatment of community-acquired respiratory tract infections, such as acute exacerbations of chronic bronchitis (AECB), constitutes a huge socioeconomic burden. In most cases, an antimicrobial agent is advocated to lessen morbidity and prevent serious clinical sequelae. Use of antimicrobial agents for AECB, however, is controversial, as it is difficult to distinguish between bacterial and nonbacterial AECB, and only marginal benefits have been reported. Antimicrobial agents, however, have reduced relapse rates, prolonged the time between exacerbations, shortened the duration of symptoms, and reduced the need for hospitalization. Microbiologic resistance and individual patient characteristics play important roles in determining the most appropriate antimicrobial agent for patients with AECB. More research on the effect of resistant bacteria on antimicrobial response rates will enable physicians to prescribe economically rational antimicrobial therapy for this common infection.

Clinical resistance encountered in the respiratory surveillance program (RESP) study: a review of the implications for the treatment of community-acquired respiratory tract infections

The Respiratory Surveillance Program (RESP) is a large-scale surveillance study of potential bacterial pathogens from respiratory tract infections that was performed over a 10-month period (July to April) during the 1999-2000 respiratory infection season. It is also the first study of its kind to derive its information entirely from community-based medical practices. This study, therefore, provides insight into the identity, frequency, and susceptibility of the possible pathogens isolated from patients encountered by primary care physicians. Reduction of antibiotic susceptibility in various bacterial pathogens may be of academic interest. However, it is only the emergence of clinical resistance (strains exhibiting minimum inhibitory concentrations above the resistance breakpoint) to commonly used antibacterial agents in the most prevalent species that has significant impact on empiric therapy choices. A review of data from RESP indicated that the most prevalent species were Moraxella catarrhalis, Haemophilus influenzae, Staphylococcus aureus, and Streptococcus pneumoniae. As expected, the prevalence of these bacterial isolates varied by disease state. The prevalence of clinical resistance to various antibiotics ranged, within these 4 species, between 0% and 92%. Resistance to the greatest number of drugs was expressed by S pneumoniae, followed by S aureus, H influenzae, and M catarrhalis. The prevalence of antibiotic resistance found among these community-isolated pathogens was surprisingly similar to that reported in hospital-based studies, suggesting that resistance is as important an issue in the community as it is in hospitals. With few exceptions, the prevalence of resistance was fairly uniform across disease states. The antibiotics most likely to encounter clinically resistant isolates during the treatment of community-acquired respiratory tract infections were penicillins, macrolides, and trimethoprim/sulfamethoxazole. The antibiotics least likely to encounter resistance were quinolones, followed by ceftriaxone and amoxicillin/clavulanate.

Frequency of pathogen occurrence and antimicrobial susceptibility among community-acquired respiratory tract infections in the respiratory surveillance program study: microbiology from the medical office practice environment

Continuing problems of antimicrobial resistance have prompted the initiation of several surveillance programs. Few, if any, of these programs focus on community-acquired respiratory tract infections seen in routine office-based practices. The Respiratory Surveillance Program (RESP; 1999-2000) in 674 community-based physician office practices in the United States determined the frequency of potential bacterial pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis in patients diagnosed clinically with community-acquired pneumonia, acute exacerbations of chronic bronchitis, and sinusitis throughout all 9 US census/geographic regions. Susceptibility to the penicillins (ampicillin, penicillin), oral cephalosporins, fluoroquinolones (gatifloxacin, levofloxacin, ciprofloxacin), macrolides (erythromycin, azithromycin, clarithromycin), tetracycline, and trimethoprim/sulfamethoxazole was determined by reference methods. Patients were required to have a culturable focus of infection, and specimens were immediately sent to a reference laboratory. Among 22,689 total specimens (610 community-acquired pneumonia, 4,779 acute exacerbation of chronic bronchitis, 16,213 sinusitis, 1,087 other), H influenzae was the most commonly isolated organism from patients with community-acquired pneumonia (38%) and acute exacerbation of chronic bronchitis (35%) in all nine geographic regions. S pneumoniae was isolated in 18% of community-acquired pneumonia cases, 13% of acute exacerbation of chronic bronchitis cases, and 11% of sinusitis cases. M catarrhalis was most commonly isolated from the nasopharynx of patients with sinusitis (29%). High-level resistance to penicillin (2 microg/mL or greater; 16% overall) and the macrolides (32% to 35%) among S pneumoniae varied both with site of infection and with geographic region. The greatest resistance was observed among isolates from the nasopharynx of patients with sinusitis and from patients from the East South Central or South Atlantic regions of the United States. Although the susceptibility of H influenzae and M catarrhalis to the tested antimicrobials did not vary with the type of infection, beta-lactamase-mediated resistance to ampicillin among H influenzae ranged from 15% in New England to 32% in the East South Central region. The fluoroquinolones were highly active against these cultured isolates from community-acquired respiratory tract infection patients, with >99% of all S pneumoniae, H influenzae, and M catarrhalis strains susceptible to gatifloxacin (MIC(90), 0.5 microg/mL) and levofloxacin (MIC(90), 2 microg/mL). The extended-spectrum fluoroquinolones appear well suited for community-acquired respiratory tract infection therapy, including pathogens other than pneumococcus, H influenzae, and M catarrhalis.

Once daily oral ofloxacin in chronic obstructive pulmonary disease exacerbation requiring mechanical ventilation: a randomised placebo-controlled trial

BACKGROUND

The role of antibiotics in treatment of patients with moderate exacerbations of chronic obstructive pulmonary disease (COPD) is uncertain, but such treatment might be useful in very severe episodes. Our objective was to assess the effects of ofloxacin in patients with exacerbations of COPD who required mechanical ventilation.

METHODS

We did a prospective, randomised, double-blind, placebo-controlled trial in 93 patients with acute exacerbation of COPD who required mechanical ventilation. Patients were randomly assigned to receive oral ofloxacin 400 mg once daily (n=47) or placebo (46) for 10 days. Primary endpoints were death in hospital and need for an additional course of antibiotics, both separately and in combination. Analysis was by intention to treat.

FINDINGS

Three patients dropped out of the study. Two (4%) patients receiving ofloxacin died in hospital and ten (22%) did so in the placebo group (absolute risk reduction 17.5%, 95% CI 4.3-30.7, p=0.01). Treatment with ofloxacin significantly reduced the need for additional courses of antibiotics (28.4%, 12.9-43.9, p=0.0006). The combined frequency of death in hospital and need for additional antibiotics was significantly lower in patients assigned to ofloxacin than in those receiving placebo (45.9%, 29.1-62.7, p<0.0001). The duration of mechanical ventilation and hospital stay was significantly shorter in the ofloxacin group than in the placebo group (absolute difference 4.2 days, 95% CI 2.5-5.9; and 9.6 days, 3.4-12.8, respectively).

INTERPRETATION

New fluoroquinolones, such as ofloxacin, are beneficial in the treatment of COPD exacerbation requiring mechanical ventilation.

Symptom resolution assessed using a patient directed diary card during treatment of acute exacerbations of chronic bronchitis

BACKGROUND

Acute exacerbations of chronic bronchitis are common and the presenting symptoms vary, although it is not clear how this should influence management. From a health care perspective, an understanding of the speed of symptom resolution is of importance to determine the success of treatment or when a change is indicated because of treatment failure.

METHODS

The response of 63 patients treated at home for exacerbations of chronic bronchitis was assessed using a patient directed diary card incorporating sputum characteristics and symptoms. Treatment was given according to the nature of the sputum at presentation; patients with purulent sputum received an antibiotic for 5 or 10 days (randomised, double blind) whereas patients with mucoid sputum received high dose inhaled steroid or placebo for 14 days (randomised, double blind).

RESULTS

The mean (SE) total diary card score at presentation was significantly higher in the purulent group than in the mucoid group (19.7 (0.9) v 16.3 (0.9); mean difference -3.4 (95% CI -6.1 to -0.7), p<0.05). In the purulent group sputum colour and volume improved rapidly and in both groups the mean (SE) total diary card score had improved by the fifth day of treatment to 13.0 (0.7) in the purulent group (mean difference -6.6 (95% CI -8.8 to -4.4), p<0.001) and 14.6 (0.8) in the mucoid group (mean difference -1.7 (95% CI -4.0 to 0.8), p<0.05), which was no longer significantly different from the stable state. Diary card scores did not differ significantly between patients who received antibiotics for 5 or 10 days in the purulent group or between patients who received inhaled fluticasone or placebo in the mucoid group.

CONCLUSIONS

Exacerbations of chronic bronchitis associated with purulent sputum have significantly worse symptoms at presentation than those with mucoid sputum. In both groups these symptoms resolve rapidly so that by the fifth day of treatment they are no different from the stable state. No significant effect was found on symptom resolution of antibiotic duration (5 v 10 days) in the purulent group or of inhaled fluticasone in the mucoid group, which resolved without antibiotics. Larger numbers may be required to demonstrate a statistically (if not clinically) significant difference.

Community-acquired lower respiratory tract infections: etiology and treatment

The current therapy for community-acquired lower respiratory tract infections is often empiric, usually involving administration of a beta-lactam or macrolide. However, the increasing prevalence of antibiotic resistance in frequently isolated respiratory tract pathogens has complicated the antimicrobial selection process. This review will discuss the incidence of various respiratory pathogens, as well as update the clinician on the various antimicrobial alternatives available, with particular emphasis on the role of the newer fluoroquinolones in the treatment of acute exacerbations of chronic bronchitis and community-acquired pneumonia.