A comparison of pivampicillin and ampicillin in exacerbations of chronic bronchitis

Thinking Outside the Bug: Molecular Targets and Strategies to Overcome Antibiotic Resistance

Since their discovery in the early 20th century, antibiotics have been used as the primary weapon against bacterial infections. Due to their prophylactic effect, they are also used as part of the cocktail of drugs given to treat complex diseases such as cancer or during surgery, in order to prevent infection. This has resulted in a decrease of mortality from infectious diseases and an increase in life expectancy in the last 100 years. However, as a consequence of administering antibiotics broadly to the population and sometimes misusing them, antibiotic-resistant bacteria have appeared. The emergence of resistant strains is a global health threat to humanity. Highly-resistant bacteria like Staphylococcus aureus (methicillin-resistant) or Enterococcus faecium (vancomycin-resistant) have led to complications in intensive care units, increasing medical costs and putting patient lives at risk. The appearance of these resistant strains together with the difficulty in finding new antimicrobials has alarmed the scientific community. Most of the strategies currently employed to develop new antibiotics point towards novel approaches for drug design based on prodrugs or rational design of new molecules. However, targeting crucial bacterial processes by these means will keep creating evolutionary pressure towards drug resistance. In this review, we discuss antibiotic resistance and new options for antibiotic discovery, focusing in particular on new alternatives aiming to disarm the bacteria or empower the host to avoid disease onset.

Antibiotics for exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Many patients with an exacerbation of chronic obstructive pulmonary disease (COPD) are treated with antibiotics. However, the value of antibiotics remains uncertain, as systematic reviews and clinical trials have shown conflicting results.

OBJECTIVES

To assess effects of antibiotics on treatment failure as observed between seven days and one month after treatment initiation (primary outcome) for management of acute COPD exacerbations, as well as their effects on other patient-important outcomes (mortality, adverse events, length of hospital stay, time to next exacerbation).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library, MEDLINE, Embase, and other electronically available databases up to 26 September 2018.

SELECTION CRITERIA

We sought to find randomised controlled trials (RCTs) including people with acute COPD exacerbations comparing antibiotic therapy and placebo and providing follow-up of at least seven days.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references and extracted data from trial reports. We kept the three groups of outpatients, inpatients, and patients admitted to the intensive care unit (ICU) separate for benefit outcomes and mortality because we considered them to be clinically too different to be summarised as a single group. We considered outpatients to have a mild to moderate exacerbation, inpatients to have a severe exacerbation, and ICU patients to have a very severe exacerbation. When authors of primary studies did not report outcomes or study details, we contacted them to request missing data. We calculated pooled risk ratios (RRs) for treatment failure, Peto odds ratios (ORs) for rare events (mortality and adverse events), and mean differences (MDs) for continuous outcomes using random-effects models. We used GRADE to assess the quality of the evidence. The primary outcome was treatment failure as observed between seven days and one month after treatment initiation.

MAIN RESULTS

We included 19 trials with 2663 participants (11 with outpatients, seven with inpatients, and one with ICU patients).For outpatients (with mild to moderate exacerbations), evidence of low quality suggests that currently available antibiotics statistically significantly reduced the risk for treatment failure between seven days and one month after treatment initiation (RR 0.72, 95% confidence interval (CI) 0.56 to 0.94; I² = 31%; in absolute terms, reduction in treatment failures from 295 to 212 per 1000 treated participants, 95% CI 165 to 277). Studies providing older antibiotics not in use anymore yielded an RR of 0.69 (95% CI 0.53 to 0.90; I² = 31%). Evidence of low quality from one trial in outpatients suggested no effects of antibiotics on mortality (Peto OR 1.27, 95% CI 0.49 to 3.30). One trial reported no effects of antibiotics on re-exacerbations between two and six weeks after treatment initiation. Only one trial (N = 35) reported health-related quality of life but did not show a statistically significant difference between treatment and control groups.Evidence of moderate quality does not show that currently used antibiotics statistically significantly reduced the risk of treatment failure among inpatients with severe exacerbations (i.e. for inpatients excluding ICU patients) (RR 0.65, 95% CI 0.38 to 1.12; I² = 50%), but trial results remain uncertain. In turn, the effect was statistically significant when trials included older antibiotics no longer in clinical use (RR 0.76, 95% CI 0.58 to 1.00; I² = 39%). Evidence of moderate quality from two trials including inpatients shows no beneficial effects of antibiotics on mortality (Peto OR 2.48, 95% CI 0.94 to 6.55). Length of hospital stay (in days) was similar in antibiotic and placebo groups.The only trial with 93 patients admitted to the ICU showed a large and statistically significant effect on treatment failure (RR 0.19, 95% CI 0.08 to 0.45; moderate-quality evidence; in absolute terms, reduction in treatment failures from 565 to 107 per 1000 treated participants, 95% CI 45 to 254). Results of this trial show a statistically significant effect on mortality (Peto OR 0.21, 95% CI 0.06 to 0.72; moderate-quality evidence) and on length of hospital stay (MD -9.60 days, 95% CI -12.84 to -6.36; low-quality evidence).Evidence of moderate quality gathered from trials conducted in all settings shows no statistically significant effect on overall incidence of adverse events (Peto OR 1.20, 95% CI 0.89 to 1.63; moderate-quality evidence) nor on diarrhoea (Peto OR 1.68, 95% CI 0.92 to 3.07; moderate-quality evidence).

AUTHORS' CONCLUSIONS

Researchers have found that antibiotics have some effect on inpatients and outpatients, but these effects are small, and they are inconsistent for some outcomes (treatment failure) and absent for other outcomes (mortality, length of hospital stay). Analyses show a strong beneficial effect of antibiotics among ICU patients. Few data are available on the effects of antibiotics on health-related quality of life or on other patient-reported symptoms, and data show no statistically significant increase in the risk of adverse events with antibiotics compared to placebo. These inconsistent effects call for research into clinical signs and biomarkers that can help identify patients who would benefit from antibiotics, while sparing antibiotics for patients who are unlikely to experience benefit and for whom downsides of antibiotics (side effects, costs, and multi-resistance) should be avoided.

Antibiotics for exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Many patients with an exacerbation of chronic obstructive pulmonary disease (COPD) are treated with antibiotics. However, the value of antibiotics remains uncertain as systematic reviews and clinical trials have shown conflicting results.

OBJECTIVES

To assess the effects of antibiotics in the management of acute COPD exacerbations on treatment failure as observed between seven days and one month after treatment initiation (primary outcome) and on other patient-important outcomes (mortality, adverse events, length of hospital stay).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE and other electronically available databases up to September 2012.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in people with acute COPD exacerbations comparing antibiotic therapy and placebo with a follow-up of at least seven days.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references and extracted data from trial reports. We kept the three groups of outpatients, inpatients and patients admitted to the intensive care unit (ICU) separate for benefit outcomes and mortality because we considered them to be clinically too different to be summarised in one group. We considered outpatients to have a mild to moderate exacerbation, inpatients to have a severe exacerbation and ICU patients to have a very severe exacerbation. Where outcomes or study details were not reported we requested missing data from the authors of the primary studies. We calculated pooled risk ratios (RR) for treatment failure, Peto odds ratios (OR) for rare events (mortality and adverse events) and weighted mean differences (MD) for continuous outcomes using fixed-effect models. We used GRADE to assess the quality of the evidence.

MAIN RESULTS

Sixteen trials with 2068 participants were included. In outpatients (mild to moderate exacerbations), there was evidence of low quality that antibiotics did statistically significantly reduce the risk for treatment failure between seven days and one month after treatment initiation (RR 0.75; 95% CI 0.60 to 0.94; I(2) = 35%) but they did not significantly reduce the risk when the meta-analysis was restricted to currently available drugs (RR 0.80; 95% CI 0.63 to 1.01; I(2) = 33%). Evidence of high quality showed that antibiotics statistically significantly reduced the risk of treatment failure in inpatients with severe exacerbations (ICU not included) (RR 0.77; 95% CI 0.65 to 0.91; I(2) = 47%) regardless of whether restricted to current drugs. The only trial with 93 patients admitted to the ICU showed a large and statistically significant effect on treatment failure (RR 0.19; 95% CI 0.08 to 0.45; high-quality evidence).Evidence of low-quality from four trials in inpatients showed no effect of antibiotics on mortality (Peto OR 1.02; 95% CI 0.37 to 2.79). High-quality evidence from one trial showed a statistically significant effect on mortality in ICU patients (Peto OR 0.21; 95% CI 0.06 to 0.72). Length of hospital stay (in days) was similar in the antibiotics and placebo groups except for the ICU study where antibiotics statistically significantly reduced length of hospital stay (mean difference -9.60 days; 95% CI -12.84 to -6.36 days). One trial showed no effect of antibiotics on re-exacerbations between two and six weeks after treatment initiation. Only one trial (N = 35) reported health-related quality of life but did not show a statistically significant difference between the treatment and control group.Evidence of moderate quality showed that the overall incidence of adverse events was higher in the antibiotics groups (Peto OR 1.53; 95% CI 1.03 to 2.27). Patients treated with antibiotics experienced statistically significantly more diarrhoea based on three trials (Peto OR 2.62; 95% CI 1.11 to 6.17; high-quality evidence).

AUTHORS' CONCLUSIONS

Antibiotics for COPD exacerbations showed large and consistent beneficial effects across outcomes of patients admitted to an ICU. However, for outpatients and inpatients the results were inconsistent. The risk for treatment failure was significantly reduced in both inpatients and outpatients when all trials (1957 to 2012) were included but not when the analysis for outpatients was restricted to currently used antibiotics. Also, antibiotics had no statistically significant effect on mortality and length of hospital stay in inpatients and almost no data on patient-reported outcomes exist. These inconsistent effects call for research into clinical signs and biomarkers that help identify patients who benefit from antibiotics and patients who experience no effect, and in whom downsides of antibiotics (side effects, costs and multi-resistance) could be avoided.

One hundred years of chronic obstructive pulmonary disease (COPD)

Chronic obstructive pulmonary disease (COPD) is an increasing health problem and one of the leading causes of morbidity and mortality worldwide, but knowledge about its pathogenesis has increased substantially in recent years. The disease results from interaction between individual risk factors (like enzymatic deficiencies) and environmental exposures to noxious agents, like cigarette smoking, occupational dusts, air pollution and infections in childhood. The main mechanisms that may contribute to airflow limitation in COPD are fixed narrowing of small airways, emphysema and luminal obstruction with mucus secretions. COPD is characterised by a chronic inflammatory process in the pulmonary tissue, with a pattern different from bronchial asthma, associated with extrapulmonary effects and is considered now a complex, systemic disease. Optimal therapeutic targeting of COPD depends on a clear understanding of the precise mechanisms of these complex processes and on early and correct evaluation of disease severity. A combination of pharmacological and non-pharmacological approaches is used to treat COPD. Bronchodilators are the mainstay of COPD treatment and can be combined with inhaled corticosteroids for greater efficacy and fewer side effects. The use of LTOT for hypoxemic patients has resulted in increased survival, and expanded drug therapy options have effectively improved dyspnoea and quality of life. Recent studies have documented the benefits of pulmonary rehabilitation. In addition, non-invasive mechanical ventilation offers new alternatives for patients with acute or chronic failure.

Optimal antibiotic therapy in bronchopulmonary infections

Therapy of bronchopulmonary infections has evolved in the past 30 years. Only in the therapy of pneumococcal infections have, precise dosage programs been developed. Therapy of pneumococcal infection is optimal with penicillin G in low dosage. None of the newer agents has altered morbidity or mortality. The best agent for the treatment of pneumonia due to Staphylococcus aureus or members of the Enterobacteriaceae has not been established. Use of combination therapy consisting of an anti-Pseudomonas penicillin and an aminoglycoside has been shown to offer the greatest success in the treatment of Pseudomonas pulmonary infections. The optimal antibiotic and dosage program for the treatment of acute bacterial exacerbations of chronic bronchitis has yet to be defined. Further comparative studies of the chemotherapy of pulmonary infections are necessary.

Review of side-effects of aminopenicillins

Side-effects of aminopenicillin therapy are reviewed on the basis of nine comparative studies of ampicillin and bacampicillin, and available literature data from investigations with talampicillin, pivampicillin, bacampicillin and amoxycillin. Diarrhoea is more common with ampicillin than with newer aminopenicillins. Exanthema do not appear more frequently with newer aminopenicillins. The frequency of upper gastrointestinal complaints in association with some of the newer aminopenicillins (amoxycillin, bacampicillin) is not more frequent than with ampicillin. All current evidence speaks in favour of a change from ampicillin to modern aminopenicillins for oral therapy.

Methacycline compared with ampicillin in acute bacterial exacerbations of chronic bronchitis. A double-blind crossover study

In order to objectively document the accepted clinical efficacy of ampicillin in treating bacterial exacerbations of chronic bronchitis, as well as to evaluate the efficacy of methacycline, a double-blind crossover study was designed. Twenty patients with chronic bronchial disease were treated for two separate acute bacterial exacerbations, once with 2 gm of ampicillin daily, and once with 600 mg of methacycline daily, for 14 days. There were a few significant differences when comparing the efficacy of the antimicrobials. For example, the daily volume of sputum significantly went from 35.6 ml initially to 20.5 ml at the end of treatment with methacycline, and from 37.4 to 18.0 ml with ampicillin. Sputum neutrophils excreted per day went from 446 to 147 million with methacycline and from 433 to 94 million with ampicillin. Gram-positive diplococci and cocci on gram stains of sputum significantly decreased form 10.6 to 3.3 with methacycline and from 16.8 to 2.1 with ampicillin. This investigation objectively documents with accepted clinical efficacy of ampicillin and proves methacycline to be an equally effective agent.