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

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 of hospital-acquired pneumonia:

Several preventive measures for VAP have been empirically tested. There is clear evidence that antibiotic-containing preventive strategies, such as SDD and oropharyngeal decontamination, are very effective in different patient populations. Selection of antibiotic resistance remains the major disadvantage of these strategies, however, limiting its applicability in settings with high levels of antibiotic resistance. This probably precludes the use of these strategies in many American settings, but may allow their use in European countries with much lower endemic levels of resistance. There is little evidence that systemic prophylaxis is effective for the prevention of VAP, and initial studies were associated with resistance problems. Of the non antibiotic-containing preventive strategies, subglottic aspiration was effective in several studies, whereas other strategies, such as immunonutrition with glutamine or the semirecumbent patient position, were effective in single studies. All these studies were executed in European ICUs. For these interventions, more data are needed on the generalizability, feasibility, and cost effectiveness. Few data support the use of sucralfate for stress ulcer prophylaxis and modulation of enteral nutrition practices as preventive measures for VAP.

Respiratory infections caused by non-typeable Haemophilus influenzae

PURPOSE OF REVIEW

This review will consider recent developments in the clinical aspects of infections due to non-typeable Haemophilus influenzae. In addition, newer developments in the areas of mechanisms of pathogenesis, host pathogen interaction, immune responses and efforts toward vaccine development will be reviewed briefly.

RECENT FINDINGS

Non-typeable H. influenzae continues to be a common cause of otitis media in infants and children, sinusitis in children and adults, pneumonia in adults, and lower respiratory tract infection in adults with chronic obstructive pulmonary disease. While the rate of beta-lactamase production by isolates of H. influenzae varies geographically, most regions show a rate of 20-35% of isolates producing beta-lactamase. Recent studies have highlighted the possible role of bacterial biofilms formed by H. influenzae as a cause of otitis media. Several lines of evidence indicate that H. influenzae causes intracellular infection in the lower respiratory tract in chronic obstructive pulmonary disease and this observation has important implications in understanding the human immune response to the bacterium. Lipooligosaccharide is an important virulence factor for H. influenzae and research is generating new information on the complex role of this molecule in colonization and infection of the respiratory tract. Several surface molecules are under active evaluation as vaccine antigens.

SUMMARY

Non-typeable H. influenzae is an important cause of respiratory tract infections in children and adults. Most strains are susceptible to amoxicillin/clavulanate, fluoroquinolones and the newer macrolides. Research in the next decade promises substantial progress in the challenge of developing vaccines for nontypeable H. influenzae.

Antibiotics in the treatment of acute exacerbations of chronic bronchitis

The benefit of antimicrobial therapy for patients with an acute exacerbation of chronic bronchitis (AECB) remains controversial for two main reasons. First, the distal airways of patients with chronic bronchitis are persistently colonised, even during clinically stable periods, with the same bacteria that have been associated with AECB. Second, bacterial infection is only one of several causes of AECB. These factors have led to conflicting analyses on the role of bacterial agents and the response to antimicrobial therapy of patients with AECB. An episode of AECB is said to be present when a patient with chronic obstructive pulmonary disease (COPD) experiences some combination of increased dyspnoea, increased sputum volume, increased sputum purulence and worsening lung function. While the average COPD patient experiences 2 - 4 episodes of AECB per year, some patients, particularly those with more severe airway obstruction, are more susceptible to these attacks than others. Bacterial agents appear to be particularly associated with AECB in patients with low lung function and those with frequent episodes accompanied by purulent sputum. Non-typeable Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis account for up to 50% of episodes of AECB. Gram-negative bacilli are more likely to occur in patients with more severe lung disease. Antibiotics have been used to ameliorate AECB, to prevent AECB and to prevent the long-term loss of lung function that characterises COPD. Numerous prevention trials have been conducted with fairly consistent results; antibiotics do not lessen the number of episodes of AECB but do reduce the number of days lost from work. Most antibiotic trials have studied the impact of treatment on episodes of AECB and results have been inconsistent, largely due to patient selection and end point definition. In patients with severe airway obstruction, especially in the presence of purulent sputum, antibiotic therapy significantly shortens the duration of symptoms and can be cost-effective. Over the past 50 years, virtually all classes of antimicrobial agents have been studied in AECB. Important considerations include penetration into respiratory secretions, spectrum of activity and antimicrobial resistance. These factors limit the usefulness of drugs such as amoxicillin, erythromycin and trimethoprim-sulfamethoxazole. Extended-spectrum oral cephalosporins, newer macrolides and doxycycline have demonstrated efficacy in clinical trials. Amoxicillin-clavulanate and flouoroquinolones should generally be reserved for patients with more severe disease. A number of investigational agents, including ketolides and newer quinolones, hold promise for treatment of AECB.