Effectiveness of mezlocillin and endotracheally administered sisomicin with or without parenteral sisomicin in the treatment of Gram-negative bronchopneumonia

Beta lactam antibiotic monotherapy versus beta lactam-aminoglycoside antibiotic combination therapy for sepsis

BACKGROUND

Optimal antibiotic treatment for sepsis is imperative. Combining a beta lactam antibiotic with an aminoglycoside antibiotic may provide certain advantages over beta lactam monotherapy.

OBJECTIVES

Our objectives were to compare beta lactam monotherapy versus beta lactam-aminoglycoside combination therapy in patients with sepsis and to estimate the rate of adverse effects with each treatment regimen, including the development of bacterial resistance to antibiotics.

SEARCH METHODS

In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11); MEDLINE (1966 to 4 November 2013); EMBASE (1980 to November 2013); LILACS (1982 to November 2013); and conference proceedings of the Interscience Conference of Antimicrobial Agents and Chemotherapy (1995 to 2013). We scanned citations of all identified studies and contacted all corresponding authors. In our previous review, we searched the databases to July 2004.

SELECTION CRITERIA

We included randomized and quasi-randomized trials comparing any beta lactam monotherapy versus any combination of a beta lactam with an aminoglycoside for sepsis.

DATA COLLECTION AND ANALYSIS

The primary outcome was all-cause mortality. Secondary outcomes included treatment failure, superinfections and adverse events. Two review authors independently collected data. We pooled risk ratios (RRs) with 95% confidence intervals (CIs) using the fixed-effect model. We extracted outcomes by intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 69 trials that randomly assigned 7863 participants. Twenty-two trials compared the same beta lactam in both study arms, while the remaining trials compared different beta lactams using a broader-spectrum beta lactam in the monotherapy arm. In trials comparing the same beta lactam, we observed no difference between study groups with regard to all-cause mortality (RR 0.97, 95% CI 0.73 to 1.30) and clinical failure (RR 1.11, 95% CI 0.95 to 1.29). In studies comparing different beta lactams, we observed a trend for benefit with monotherapy for all-cause mortality (RR 0.85, 95% CI 0.71 to 1.01) and a significant advantage for clinical failure (RR 0.75, 95% CI 0.67 to 0.84). No significant disparities emerged from subgroup and sensitivity analyses, including assessment of participants with Gram-negative infection. The subgroup of Pseudomonas aeruginosa infections was underpowered to examine effects. Results for mortality were classified as low quality of evidence mainly as the result of imprecision. Results for failure were classified as very low quality of evidence because of indirectness of the outcome and possible detection bias in non-blinded trials. We detected no differences in the rate of development of resistance. Nephrotoxicity was significantly less frequent with monotherapy (RR 0.30, 95% CI 0.23 to 0.39). We found no heterogeneity for all these comparisons.We included a small subset of studies addressing participants with Gram-positive infection, mainly endocarditis. We identified no difference between monotherapy and combination therapy in these studies.

AUTHORS' CONCLUSIONS

The addition of an aminoglycoside to beta lactams for sepsis should be discouraged. All-cause mortality rates are unchanged. Combination treatment carries a significant risk of nephrotoxicity.

A survival benefit of combination antibiotic therapy for serious infections associated with sepsis and septic shock is contingent only on the risk of death: a meta-analytic/meta-regression study

OBJECTIVE

To assess whether a potential benefit with combination antibiotic therapy is restricted to the most critically ill subset of patients, particularly those with septic shock.

DATA SOURCES

OVID MEDLINE (1950-October 2009), EMBASE (1980-October 2009), the Cochrane Central Register of Controlled Trials (to third quarter 2009), the ClinicalTrial.gov database, and the SCOPUS database.

STUDY SELECTION

Randomized or observational studies of antimicrobial therapy of serious bacterial infections potentially associated with sepsis or septic shock. Fifty studies met entry criteria.

DATA EXTRACTION

Study design, mortality/clinical response, and other variables were extracted independently by two reviewers. When possible, study datasets were split into mutually exclusive groups with and without shock or critical illness.

DATA SYNTHESIS

Although a pooled odds ratio indicated no overall mortality/clinical response benefit with combination therapy (odds ratio, 0.856; 95% confidence interval, 0.71-1.03; p = .0943; I = 45.1%), stratification of datasets by monotherapy mortality risk demonstrated substantial benefit in the most severely ill subset (monotherapy risk of death >25%; odds ratio of death, 0.51; 95% confidence interval, 0.41-0.64; I = 8.6%). Of those datasets that could be stratified by the presence of shock/critical illness, the more severely ill group consistently demonstrated increased efficacy of a combination therapy strategy (odds ratio, 0.49; 95% confidence interval, 0.35-0.70; p < .0001; I = 0%). An increased risk of death was found in low-risk patients (risk of death <or=15% in the monotherapy arm) exposed to combination therapy (odds ratio, 1.53; 95% confidence interval, 1.16-2.03; p = .003; I = 8.2%). Meta-regression indicated that efficacy of combination therapy was dependent only on the risk of death in the monotherapy group.

CONCLUSION

Combination antibiotic therapy improves survival and clinical response of high-risk, life-threatening infections, particularly those associated with septic shock but may be detrimental to low-risk patients.

Beta lactam antibiotic monotherapy versus beta lactam-aminoglycoside antibiotic combination therapy for sepsis

BACKGROUND

Optimal antibiotic treatment for sepsis is imperative. Combining a beta-lactam antibiotic with an aminoglycoside antibiotic may have certain advantages over beta-lactam monotherapy.

OBJECTIVES

We compared clinical outcomes for beta lactam-aminoglycoside combination therapy versus beta lactam monotherapy for sepsis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 3, 2004); MEDLINE (1966 to July 2004); EMBASE (1980 to March 2003); LILACS (1982 to July 2004); and conference proceedings of the Interscience Conference of Antimicrobial Agents and Chemotherapy (1995 to 2003). We scanned citations of all identified studies and contacted all corresponding authors.

SELECTION CRITERIA

We included randomized and quasi-randomized trials comparing any beta-lactam monotherapy to any combination of one beta-lactam and one aminoglycoside for sepsis.

DATA COLLECTION AND ANALYSIS

The primary outcome was all-cause fatality. Secondary outcomes included treatment failure, superinfections, colonization, and adverse events. Two authors independently collected data. We pooled relative risks (RR) with their 95% confidence intervals (CI) using the fixed effect model. We extracted outcomes by intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 64 trials, randomizing 7586 patients. Twenty trials compared the same beta-lactam in both study arms, while the remaining compared different beta-lactams using a broader spectrum beta-lactam in the monotherapy arm. In studies comparing the same beta-lactam, we observed no difference between study groups with regard to all-cause fatality, RR 1.01 (95% CI 0.75-1.35) and clinical failure, RR 1.11 (95% CI 0.95-1.29). In studies comparing different beta-lactams, we observed an advantage to monotherapy: all cause fatality RR 0.85 (95% CI 0.71-1.01), clinical failure RR 0.77 (95% CI 0.69-0.86). No significant disparities emerged from subgroup and sensitivity analyses, including the assessment of patients with Gram-negative and Pseudomonas aeruginosa infections. We detected no differences in the rate of resistance development. Adverse events rates did not differ significantly between the study groups overall, although nephrotoxicity was significantly more frequent with combination therapy, RR 0.30 (95% CI 0.23-0.39). We found no heterogeneity for all comparisons. We included a small subset of studies addressing patients with Gram-positive infections, mainly endocarditis. We identified no difference between monotherapy and combination therapy in these studies.

AUTHORS' CONCLUSIONS

The addition of an aminoglycoside to beta-lactams for sepsis should be discouraged. All-cause fatality rates are unchanged. Combination treatment carries a significant risk of nephrotoxicity.

Effect of Aminoglycoside and β‐Lactam Combination Therapy versus β‐Lactam Monotherapy on the Emergence of Antimicrobial Resistance: A Meta‐analysis of Randomized, Controlled Trials

BACKGROUND

The addition of an aminoglycoside to a beta -lactam therapy regimen has been suggested to have a beneficial effect in delaying or preventing the development of antimicrobial resistance. We studied the effect of aminoglycoside/ beta -lactam combination therapy versus beta-lactam monotherapy on the emergence of resistance.

METHODS

We performed a meta-analysis of randomized, controlled trials (RCTs) that compared aminoglycoside/ beta-lactam combination therapy with beta-lactam monotherapy and that reported data regarding the emergence of resistance (primary outcome) and/or development of superinfection, treatment failure, treatment failure attributable to emergence of resistance, treatment failure attributable to superinfection, all-cause mortality during treatment, and mortality due to infection. Data for this meta-analysis were identified from the PubMed database, Current Contents database, Cochrane central register of controlled trials, and references in relevant articles.

RESULTS

A total of 8 RCTs were included in the analysis. Beta -lactam monotherapy was not associated with a greater emergence of resistance than was the aminoglycoside/ beta-lactam combination (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.56-1.47). Actually, beta -lactam monotherapy was associated with fewer superinfections (OR, 0.62; 95% CI, 0.42-0.93) and fewer treatment failures (OR, 0.62; 95% CI, 0.38-1.01). Rates of treatment failure attributable to emergence of resistance (OR, 3.09; 95% CI, 0.75-12.82), treatment failure attributable to superinfection (OR, 0.60; 95% CI, 0.33-1.10), all-cause mortality during treatment (OR, 0.70; 95% CI, 0.40-1.25), and mortality due to infection (OR, 0.74; 95% CI, 0.46-1.21) did not differ significantly between the 2 regimens.

CONCLUSIONS

Compared with beta-lactam monotherapy, the aminoglycoside/ beta-lactam combination was not associated with a beneficial effect on the development of antimicrobial resistance among initially antimicrobial-susceptible isolates.

Beta lactam monotherapy versus beta lactam-aminoglycoside combination therapy for sepsis in immunocompetent patients: systematic review and meta-analysis of randomised trials

OBJECTIVE

To compare beta lactam monotherapy with beta lactam-aminoglycoside combination therapy for severe infections.

DATA SOURCES

Medline, Embase, Lilacs, Cochrane Library, and conference proceedings, to 2003; references of included studies; contact with all authors. No restrictions, such as language, year of publication, or publication status.

STUDY SELECTION

All randomised trials of beta lactam monotherapy compared with beta lactam-aminoglycoside combination therapy for patients without neutropenia who fulfilled criteria for sepsis.

DATA SELECTION

Two reviewers independently applied selection criteria, performed quality assessment, and extracted the data. The primary outcome assessed was all cause fatality by intention to treat. Relative risks were pooled with the random effect model (relative risk < 1 favours monotherapy).

RESULTS

64 trials with 7586 patients were included. There was no difference in all cause fatality (relative risk 0.90, 95% confidence interval 0.77 to 1.06). 12 studies compared the same beta lactam (1.02, 0.76 to 1.38), and 31 studies compared different beta lactams (0.85, 0.69 to 1.05). Clinical failure was more common with combination treatment overall (0.87, 0.78 to 0.97) and among studies comparing different beta lactams (0.76, 0.68 to 0.86). There was no advantage to combination therapy among patients with Gram negative infections (1835 patients) or Pseudomonas aeruginosa infections (426 patients). There was no difference in the rate of development of resistance. Nephrotoxicity was significantly more common with combination therapy (0.36, 0.28 to 0.47). Heterogeneity was not significant for these comparisons.

CONCLUSIONS

In the treatment of sepsis the addition of an aminoglycoside to beta lactams should be discouraged. Fatality remains unchanged, while the risk for adverse events is increased.

Double-blind study of endotracheal tobramycin in the treatment of gram-negative bacterial pneumonia. The Endotracheal Tobramycin Study Group

A prospective, double-blind, placebo-controlled study was conducted to determine the safety and efficacy of endotracheal tobramycin (ETT) for treatment of gram-negative bacterial pneumonia. Patients were randomized to either 40 mg of tobramycin or a placebo instilled endotracheally every 8 h. Patients also received intravenous tobramycin plus either cefazolin or piperacillin. Of 85 patients enrolled, 41 were assessable. Most microbiologic diagnoses were made by endotracheal aspiration with strict grading criteria. The clinical-radiographic responses of patients and standard demographic data were recorded. Pseudomonas aeruginosa, "multiple pathogens," and Klebsiella-Enterobacter-Serratia-Citrobacter species were isolated in 41, 32, and 15% of the instances, respectively. Causative pathogens were eradicated from sputum significantly more frequently by patients who received ETT (P less than 0.05). However, no significant differences were noted in the clinical outcomes of the two study groups. No local adverse reactions attributable to the administration of this agent were observed, but four patients had supraventricular tachycardia, compared with none who received the placebo (P = 0.053). ETT may be considered as adjunctive therapy for seriously ill individuals.

Local treatment of respiratory infections with antibiotics

Local administration of antibiotics for the treatment of respiratory infections has the potential advantage of reduced systemic toxicity and increased drug concentration at the site of infection. This article reviews the basic principles of pulmonary drug delivery using aerosols and the clinical efficacy of local antibiotic therapy of respiratory infections. Clinical studies have been conducted with locally administered aminoglycosides, penicillins, cephalosporins, and polypeptides. The results of these investigations and the pharmacokinetic aspects of pulmonary antibiotic delivery are summarized.

Serum gentamicin concentrations during intratracheal administration

In artificially ventilated patients, intratracheal aminoglycoside administration is used as a form of prophylaxis of broncho-pulmonary infections. In artificially ventilated patients with multiple organ failure, serum gentamicin concentrations were measured dependent on renal function after endotracheal administration. A standard commercial ampule of 40 mg gentamicin in a 1 ml solution was injected in undiluted form, intratracheally through the tubus , every 6 h. In the patients without renal failure, values over 1 microgram/ml were only found in certain individual cases and reached a maximum of 1.5 micrograms/ml. In patients with renal failure even after prolonged application, the average serum concentrations were between 2 and 3.5 micrograms/ml. In a very few cases, however, levels of up to 10.5 micrograms/ml were measured. The daily serum pattern revealed a distinct dependence on the administration; 1 h after administration there was an increase in the serum concentrations which decreased to the initial levels after 6 h. When patients with renal impairment are given an aminoglycoside intratracheally, serum levels of up to 10.5 micrograms/ml may be reached and thus additional systemic aminoglycoside therapy should be avoided.

A review of the therapeutic efficacy of aerosolized and endotracheally instilled antibiotics

Achievement of sufficient concentrations of aerosolized antibiotic at the site of infection is limited by technical problems in antibiotic delivery and by drug inactivation. Antibiotic delivery by aerosolization is generally associated with minimal systemic absorption, whereas systemic absorption may be significant after endotracheal instillation. Methodologic problems make correlations between clinical response and sputum antibiotic concentrations difficult. Studies suggest that aerosolized antibiotics are of little value in the treatment of chronic bronchopulmonary infections. Endotracheal instillation appears to be associated with favorable clinical responses, possibly due to enhanced antibiotic delivery to the site of infection. Prophylactic aerosolized antibiotics are effective in altering sputum flora; reduction in mortality from acquired pneumonia has not been demonstrated. The development of resistant organisms may occur as a result of prophylactic treatment.