Aminoglycosides for intra-abdominal infection: equal to the challenge?

The 2021 Dutch Working Party on Antibiotic Policy (SWAB) guidelines for empirical antibacterial therapy of sepsis in adults

BACKGROUND

The Dutch Working Party on Antibiotic Policy (SWAB) in collaboration with relevant professional societies, has updated their evidence-based guidelines on empiric antibacterial therapy of sepsis in adults.

METHODS

Our multidisciplinary guideline committee generated ten population, intervention, comparison, and outcome (PICO) questions relevant for adult patients with sepsis. For each question, a literature search was performed to obtain the best available evidence and assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. The quality of evidence for clinically relevant outcomes was graded from high to very low. In structured consensus meetings, the committee formulated recommendations as strong or weak. When evidence could not be obtained, recommendations were provided based on expert opinion and experience (good practice statements).

RESULTS

Fifty-five recommendations on the antibacterial therapy of sepsis were generated. Recommendations on empiric antibacterial therapy choices were differentiated for sepsis according to the source of infection, the potential causative pathogen and its resistance pattern. One important revision was the distinction between low, increased and high risk of infection with Enterobacterales resistant to third generation cephalosporins (3GRC-E) to guide the choice of empirical therapy. Other new topics included empirical antibacterial therapy in patients with a reported penicillin allergy and the role of pharmacokinetics and pharmacodynamics to guide dosing in sepsis. We also established recommendations on timing and duration of antibacterial treatment.

CONCLUSIONS

Our multidisciplinary committee formulated evidence-based recommendations for the empiric antibacterial therapy of adults with sepsis in The Netherlands.

Antibiotic Resistance in Community-Acquired Intra-Abdominal Infections: Diabetes Mellitus as a Risk Factor

Background: Antimicrobial drug resistance in community-acquired (CA) infections is a growing problem. Knowing the local epidemiology is essential to design empirical antibiotic therapy. Therefore, we conducted this study to evaluate the resistance patterns of microorganisms isolated from surgical samples of community-acquired intra-abdominal infections (IAIs) and to determine the factors associated with resistance. Methods: We analyzed retrospectively the records of patients treated from January 2015 to June 2017 who had IAIs with positives aerobic cultures performed in the first 72 hours after admission. Surgical site infections, abdominal wall procedures, peritoneal dialysis catheters, and patients with admissions in the prior month were excluded. To identify the factors associated with resistance, we considered the resistance to the regimen recommended at our institution, ampicillin/sulbactam (AMS) plus ciprofloxacin (CIP). Results: There were 119 patients with 133 isolates, 59% women, and mean age 54 years. The main sources of infection were appendicitis (38%) and cholecystitis (20%), with 64 patients presenting a complicated IAI (cIAI), defined by the presence of peritonitis (55%). Resistance in Enterobacteriaceae was AMS 32% (6.4% intermediate resistance), CIP 31%, cefotaxime 9%, piperacillin/tazobactam (PTZ) 3%, trimethoprim/sulfamethoxazole 32%, gentamicin 9.5%, and amikacin 2%. Considering all patients, resistance to AMS + CIP was 16.8%. Factors associated with resistant to this regimen was, by univariable and multivariable analysis, the presence of diabetes mellitus (odds ratio [OR] 3.6; 95% confidence interval [CI] 1.1-11.6; p = 0.03). Female gender (OR 2.7; CI 0.9-8.4; p = 0.08) and complicated IAI (OR 2.0; CI 0.7-5.4; p = 0.17) were associated with resistance but did not reach statistical significance. Conclusion: High resistance to CIP and AMS was observed. Although the combination of AMS + CIP offers coverage for 84% of patients, PTZ should be considered as an option for patients with severe infections or diabetes mellitus. Finding factors associated with antibiotic resistance could help to select empirical therapy for CA IAIs better.

Adjunctive therapy of intravenous colistin to intravenous tigecycline for adult patients with non-bacteremic post-surgical intra-abdominal infection due to carbapenem-resistant Acinetobacter baumannii

Post-surgical intra-abdominal infections (IAIs) due to carbapenem-resistant Acinetobacter baumannii (CRAB) are difficult to treat due to suboptimal peritoneal penetrations of several antimicrobial agents. Tigecycline has favorable outcomes of treating IAIs due to multidrug-resistant organisms but occurrence of breakthrough bacteremia has been observed because this agent has low serum level. Colistin has in vitro activity against CRAB but data on treatment of IAIs is limited due to poor peritoneal penetration. The purpose of this retrospective study is to explore the outcomes of adjunctive intravenous (IV) colistin to IV tigecycline in the treatment of IAIs caused by CRAB. Of 28 patients with non-bacteremic post-surgical IAIs due to CRAB, 14 patients received IV tigecycline alone and 14 patients received IV tigecycline with IV colistin. The 14-day, 30-day, in-hospital mortality rates, the rate of breakthrough bacteremia and the rate of bacterial eradication were not significantly different. The adjunctive therapy of IV colistin was associated with significantly higher rates of renal complications (10/14) than those receiving IV tigecycline alone (3/14) (P value = 0.023). In addition, the patients receiving adjunctive IV colistin had significantly more unfavorable non-clinical outcomes including longer length of hospital stay (P value = 0.049) and higher antimicrobial cost (P value = 0.008) and non-antimicrobial costs (P value = 0.037). In this study, adjunctive IV colistin to conventional IV tigecycline in the treatment of non-bacteremic post-surgical IAIs caused by CRAB did not yield clinical benefit but caused higher renal complication and unfavorable non-clinical outcomes.

Outcomes of empiric aminoglycoside monotherapy for Pseudomonas aeruginosa bacteremia

We evaluated 30-day mortality in patients with Pseudomonas aeruginosa bacteremia. There was no significant difference in mortality among patients who received functional aminoglycoside monotherapy versus inappropriate empiric therapy. Among patients given appropriate empiric therapy, functional aminoglycoside monotherapy was associated with less favorable outcomes compared to beta-lactam monotherapy.

Spatiotemporal pharmacodynamics of meropenem- and tobramycin-treated Pseudomonas aeruginosa biofilms

Objectives

The selection and dose of antibiotic therapy for biofilm-related infections are based on traditional pharmacokinetic studies using planktonic bacteria. The objective of this study was to characterize the time course and spatial activity of human exposure levels of meropenem and tobramycin against Pseudomonas aeruginosa biofilms grown in an in vitro flow-chamber model.

Methods

Pharmacokinetic profiles of meropenem and tobramycin used in human therapy were administered to GFP-labelled P. aeruginosa PAO1 grown in flow chambers for 24 or 72 h. Images were acquired using confocal laser scanning microscopy throughout antibiotic treatment. Bacterial biomass was measured using COMSTAT and pharmacokinetic/pharmacodynamic models were fitted using NONMEM7.

Results

Meropenem treatment resulted in more rapid and sustained killing of both the 24 and 72 h PAO1 biofilm compared with tobramycin. Biofilm regrowth after antibiotic treatment occurred fastest with tobramycin. Meropenem preferentially killed subpopulations within the mushroom cap of the biofilms, regardless of biofilm maturity. The spatial killing by tobramycin varied with biofilm maturity. A tobramycin-treated 24 h biofilm resulted in live and dead cells detaching from the biofilm, while treatment of a 72 h biofilm preferentially killed subpopulations on the periphery of the mushroom stalk. Regrowth occurred primarily on the mushroom caps. Combination meropenem and tobramycin therapy resulted in rapid and efficient killing of biofilm cells, with a spatial pattern similar to meropenem alone.

Conclusions

Simulated human concentrations of meropenem and tobramycin in young and mature PAO1 biofilms exhibited differences in temporal and spatial patterns of killing and antibiotic tolerance development.

The Surgical Infection Society Revised Guidelines on the Management of Intra-Abdominal Infection

BACKGROUND

Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.

METHODS

Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.

RESULTS

This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.

SUMMARY

The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline.

Management of Severe Sepsis of Abdominal Origin

Severe sepsis is a life-threatening condition that may occur as a sequela of intra-abdominal infections (IAIs) of all types. Diagnosis of IAIs is predicated upon the combination of physical examination and imaging techniques. Diffuse peritonitis usually requires urgent surgical intervention. In the absence of diffuse peritonitis, abdominal computed tomography remains the most useful test for the diagnosis of IAIs, and is essential to both guide therapeutic interventions and evaluate suspected treatment failure in the critically ill patient. Parameters most consistently associated with poor outcomes in patients with IAIs include increased illness severity, failed source control, inadequate empiric antimicrobial therapy, and healthcare-acquired, as opposed to community-acquired infection. Whereas community-acquired IAI is characterized predominantly by enteric gram-negative bacilli and anaerobes that are susceptible to narrow-spectrum agents, healthcare-acquired IAI (e.g., anastomotic dehiscence, postoperative organ-space surgical site infection) frequently involves at least one multi-drug resistant pathogen, necessitating broad-spectrum therapy guided by both culture results and local antibiograms. The cornerstone of effective treatment for abdominal sepsis is early and adequate source control, which is supplemented by antibiotic therapy, restoration of a functional gastrointestinal tract (if possible), and support of organ dysfunction. Furthermore, mitigation of deranged immune and coagulation responses via therapy with recombinant human activated protein C may improve survival significantly in severe cases complicated by septic shock and multiple organ dysfunction syndrome.

Aminoglycosides for Treatment of Bacteremia Due to Carbapenem-Resistant Klebsiella pneumoniae

Aminoglycoside treatment of carbapenem-resistant (CR) Klebsiella pneumoniae bacteremia was associated with a 70% rate (23/33) of 30-day survival. Successful treatment was associated with sources of bacteremia amenable to reliable aminoglycoside pharmacokinetics (P = 0.037), acute physiology and chronic health evaluation II (APACHE II) scores of <20 (P = 0.16), and nonfatal underlying diseases (P = 0.015). Success rates were 78% and 100% if ≥2 and all 3 factors were present, respectively. Clinicians may consider the use of aminoglycosides against CR K. pneumoniae bacteremia if strains are susceptible and the sources of infection are amenable to reliable pharmacokinetics.

Rational use of aminoglycosides--review and recommendations by the Swedish Reference Group for Antibiotics (SRGA)

The Swedish Reference Group for Antibiotics (SRGA) has carried out a risk-benefit analysis of aminoglycoside treatment based on clinical efficacy, antibacterial spectrum, and synergistic effect with beta-lactam antibiotics, endotoxin release, toxicity, and side effects. In addition, SRGA has considered optimal dosage schedules and advice on serum concentration monitoring, with respect to variability in volume of drug distribution and renal clearance. SRGA recommends that aminoglycoside therapy should be considered in the following situations: (1) progressive severe sepsis and septic shock, in combination with broad-spectrum beta-lactam antibiotics, (2) sepsis without shock, in combination with broad-spectrum beta-lactam antibiotics if the infection is suspected to be caused by multi-resistant Gram-negative pathogens, (3) pyelonephritis, in combination with a beta-lactam or quinolone until culture and susceptibility results are obtained, or as monotherapy if a serious allergy to beta-lactam or quinolone antibiotics exists, (4) serious infections caused by multi-resistant Gram-negative bacteria when other alternatives are lacking, and (5) endocarditis caused by difficult-to-treat pathogens when monotherapy with beta-lactam antibiotics is not sufficient. Amikacin is generally more active against extended-spectrum beta-lactamase (ESBL)-producing and quinolone-resistant Escherichia coli than other aminoglycosides, making it a better option in cases of suspected infection caused by multidrug-resistant Enterobacteriaceae. Based on their resistance data, local drug committees should decide on the choice of first-line aminoglycoside. Unfortunately, aminoglycoside use is rarely followed up with audiometry, and in Sweden we currently have no systematic surveillance of adverse events after aminoglycoside treatment. We recommend routine assessment of adverse effects, including hearing loss and impairment of renal function, if possible at the start and after treatment with aminoglycosides, and that these data should be included in hospital patient safety surveillance and national quality registries.

White paper: recommendations on the conduct of superiority and organism-specific clinical trials of antibacterial agents for the treatment of infections caused by drug-resistant bacterial pathogens

There is a critical need for new pathways to develop antibacterial agents to treat life-threatening infections caused by highly resistant bacteria. Traditionally, antibacterial agents have been studied in noninferiority clinical trials that focus on one site of infection (eg, pneumonia, intra-abdominal infection). Conduct of superiority trials for infections caused by highly antibiotic-resistant bacteria represents a new, and as yet, untested paradigm for antibacterial drug development. We sought to define feasible trial designs of antibacterial agents that could enable conduct of superiority and organism-specific clinical trials. These recommendations are the results of several years of active dialogue among the white paper's drafters as well as external collaborators and regulatory officials. Our goal is to facilitate conduct of new types of antibacterial clinical trials to enable development and ultimately approval of critically needed new antibacterial agents.

Management of aminoglycosides in the intensive care unit

Antibacterial resistance is increasing throughout the world, while the development of new agents is slowly progressing. In addition, the increasing prevalence of fluoroquinolone resistance may force many practitioners to choose an aminoglycoside agent in gram-negative regimens. Aminoglycosides are bactericidal agents with potent activity against gram-negative infections and activity against gram-positive infections when added to a cell wall active antimicrobial-based regimen. These agents may be dosed multiple times a day or consolidated as high-dose, extended-interval dosing to maximize pharmacokinetic and pharmacodynamic properties to achieve possible improved efficacy with reduced toxicity. Clinical application includes the treatment of bacteremia, endocarditis, health-care and nosocomial pneumonias, intra-abdominal infections, and others. Nephrotoxicity and ototoxicity are potential risks of aminoglycoside therapy that may be minimized with serum monitoring and short courses of therapy.

Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003-2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

Diagnosis and Management of Complicated Intra-abdominal Infection in Adults and Children: Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003–2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

The use of carbapenems in the treatment of serious infections

Inadequate initial antimicrobial treatment in serious infections leads to increased mortality. Achieving adequate treatment is increasingly difficult because of the increasing prevalence of multidrug-resistant (MDR) pathogens. The carbapenems are potent, broad-spectrum antibiotics that have been shown to be safe and efficacious therapies in the treatment of serious infections. This review is intended to compare the 4 major members of the carbapenem class, which include imipenem, meropenem, ertapenem, and doripenem, with other widely used antimicrobial agents in the intensive care unit (ICU). The carbapenems are potent, broad-spectrum antibiotics that have been shown to be safe and efficacious therapies in the treatment of serious infections. They provide better gram-negative coverage than other beta-lactams and are stable against extended-spectrum beta-lactamases and AmpC beta-lactamases, making them effective in the treatment of many MDR bacteria. The newly approved carbapenem, doripenem, may help preserve the utility of the carbapenem class.

Aminoglycoside drugs in clinical practice: an evidence-based approach

Resistant bacteria have renewed our interest in the aminoglycoside drugs. Evidence on the efficiency of aminoglycosides in their different clinical uses is available from numerous randomized controlled trials and has been accrued and examined in recent systematic reviews and meta-analyses. Their results show that aminoglycosides should not be added to broad-spectrum beta-lactams to achieve synergism in treating Gram-negative infections as combination does not improve efficacy and adds side effects. The evidence from randomized trials in humans does not support the use of aminoglycosides in staphylococcal or streptococcal endocarditis, and is lacking for endocarditis caused by enterococci. Aminoglycosides are efficacious and safe as single drugs for the treatment of pyelonephritis and sepsis of a urinary source, but their efficacy might be lower than that of beta-lactams in Gram-negative infections of other sources. In patients with no risk factors, aminoglycosides are as safe as beta-lactams regarding side effects. They probably induce less resistance. Pragmatic large trials are needed to answer open clinical questions on the use of aminoglycosides.

Carbapenems: a potent class of antibiotics

The purpose of this review is to assess the relative strengths and weaknesses of individual members of the carbapenem class of antibiotics. Clinical trials and review articles were identified from a Medline search (1979 - July 2006), in addition to, reference citations from identified publications, abstracts from the Interscience Conferences on Antimicrobial Agents and Chemotherapy and the 12th International Congress on Infectious Disease, and package inserts. Articles in English were reviewed, with emphasis on those containing efficacy or safety data. Carbapenems bind to critical penicillin-binding proteins, disrupting the growth and structural integrity of bacterial cell walls. They provide enhanced anaerobic and Gram-negative coverage as compared with other beta-lactams and their stability against extended-spectrum beta-lactamases (ESBLs) makes them an effective treatment option. The most common adverse effects are infusion-site complications and gastrointestinal distress. Ertapenem has limited efficacy against non-fermenting, Gram-negative bacteria, restricting its use to community-acquired infections. Imipenem is slightly more effective against Gram-positive organisms and meropenem slightly more effective against Gram-negative organisms. However, both have broad-spectrum activity, including non-fermenting, Gram-negative bacteria. Among non-fermenting, Gram-negatives, resistance to imipenem in particular is increasing. Doripenem is in late-stage clinical development and combines the broad-spectrum coverage of imipenem and meropenem, and more potent activity against Pseudomonas aeruginosa. Due to the increasing challenges represented by ESBLs and multi-drug resistant organisms, the carbapenems are assuming a greater role in the treatment of serious infections. Imipenem and meropenem are presently available and have been shown to be effective against nosocomial infections. Doripenem is an investigational carbapenem that has completed Phase III clinical trials and that has the potential to improve on this efficacy and minimize the emergence of resistance to the carbapenem class.

Antimicrobial treatment for intra-abdominal infections

Treatment of patients with complicated intra-abdominal infections involves antimicrobial therapy, generally in conjunction with an interventional procedure to control the source of the infection. Antimicrobial regimens effective against common gram-negative and anaerobic enteric pathogens are the mainstay of therapy. For patients with community-acquired intra-abdominal infections, efficacy is comparable among the various single-agent or combination regimens recommended for therapy. Narrower-spectrum antimicrobial agents with a low potential for iatrogenic complications are appropriate for these patients. Patients with nosocomially-acquired, intra-abdominal infections are more likely to harbor resistant pathogens. Inadequate empiric antimicrobial therapy is associated with treatment failure and death. Therefore, broader spectrum antimicrobial regimens are recommended for these patients. In addition to coverage of more resistant gram-negative bacilli and anaerobes, use of agents effective against enterococci, resistant staphylococci and Candida should be considered. De-escalation of an initially broad antimicrobial regimen should be undertaken once definitive culture results are available.

Intra-abdominal infections

PURPOSE OF REVIEW

The aim of this article is to outline developments in the three cornerstones of treatment of intra-abdominal infections during critical illness: source control; antimicrobial therapy; and mitigation of deranged immune and coagulation responses.

RECENT FINDINGS

Although adequate source control remains the goal of mechanical management of intra-abdominal infections, neither planned re-laparotomy nor open-abdomen management appears to offer a survival benefit as compared with on-demand re-laparotomy. Novel approaches to restoration of a functional gastrointestinal tract have emerged as alternatives to more invasive surgery. A persistent increase in the prevalence of intra-abdominal infections caused by multidrug resistant pathogens has led researchers to investigate shorter-course antimicrobial therapy and other antibiotic administration strategies with encouraging initial results. Therapy with recombinant human activated protein C should now be considered for patients with severe abdominal sepsis associated with a high risk of death.

SUMMARY

Because randomized controlled trials of intra-abdominal infections involve critically ill patients infrequently, only limited evidence-based recommendations regarding the management of these patients may be drawn. Therapy should focus above all else on timely obtainment of adequate source control, in conjunction with judicious use of antimicrobial therapy dictated by individual patient risk factors for infection with multidrug resistant pathogens.

Efficacy and safety of aminoglycoside monotherapy: systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

This study sought to compare the efficacy and adverse effects of any aminoglycoside as a single antibiotic with other antibiotics for the treatment of patients with infection.

METHODS

Systematic review of the literature and meta-analysis. We searched for randomized controlled trials comparing the efficacy of single aminoglycoside antibiotic treatment with one or more non-aminoglycoside antibiotic for patients with infection in the Cochrane Library, MEDLINE, EMBASE, LILACS, databases of ongoing trials and conference proceedings. Two reviewers assessed trial eligibility, quality and extracted data. Pooled relative risks (RR) with 95% confidence intervals (CI) were calculated for dichotomous data.

RESULTS

The search yielded 37 trials of which 26 included patients with urinary tract infection. Aminoglycosides were equally effective as comparators in the analysis of the primary outcomes, all-cause mortality (RR 1.11, 95% CI 0.68, 1.81, 9 trials, 503 patients) and treatment failure (RR 1.10, 95% CI 0.96, 1.27, 32 trials, 1890 patients). Aminoglycosides were associated with a significantly higher rate of bacteriological failure at end of therapy (RR 1.44, 95% CI 1.21, 1.72, 27 trials, 1668 patients). Subgroup analyses according to quality of trial, type of antibiotics, source of infection and rate of clinical sepsis did not alter the outcomes. Less adverse effects in total but more nephrotoxic effects were observed in patients treated with aminoglycosides.

CONCLUSIONS

The present data support the use of aminoglycosides for urinary tract infections. The paucity of trials including patients with sepsis or reporting on mortality precludes firm recommendations for patients with infections other than of the urinary tract.

Aminoglycoside-based triple-antibiotic therapy versus monotherapy for children with ruptured appendicitis

OBJECTIVE

We conducted a retrospective cohort study to compare the use of triple therapy versus monotherapy for children and adolescents with perforated appendicitis and to determine whether there has been a transition to monotherapy within the freestanding children's hospitals that contribute to the Pediatric Health Information System database.

METHODS

We used the Pediatric Health Information System database, which includes billing and discharge data for 32 children's hospitals in the United States, to examine the trend in antibiotic usage and whether the postappendectomy antibiotic regimen was associated with differences in complication-related readmissions, length of stay, or charges in a population of children and adolescents with ruptured appendicitis and discharge dates between March 1, 1999, and September 30, 2004. Pairwise regression analyses were performed to compare the most common monotherapy regimens with the triple therapy.

RESULTS

A total of 8545 patients met the inclusion criteria, of whom 58%, over the entire study period, received the aminoglycoside-based triple antibiotic therapy on postoperative day 1. There was, however, a notable transition over this 6-year period, from 69% to 52% of surgeons using aminoglycoside-based combination therapy. There were no significant differences in the odds of readmission at 30 days except for the group receiving ceftriaxone, which was associated with significantly decreased odds. The subgroup receiving piperacillin/tazobactam monotherapy demonstrated significantly decreased length of stay (-0.90 days) and total hospital charges, and the group receiving cefoxitin demonstrated significantly decreased length of stay (-1.89 days), as well as decreased pharmacy and total hospital charges.

CONCLUSIONS

Single-agent antibiotic therapy in the treatment of perforated appendicitis is being used with increasing frequency, is at least equal in efficacy to the traditional aminoglycoside-based combination therapy, and may offer improvements in terms of length of stay, pharmacy charges, and hospital charges.

Meta-analysis: randomized controlled trials of clindamycin/aminoglycoside vs. beta-lactam monotherapy for the treatment of intra-abdominal infections

AIM

To compare the effectiveness and safety of clindamycin/aminoglycoside with broad-spectrum beta-lactam monotherapy in patients with intra-abdominal infections by performing a meta-analysis of randomized controlled trials (RCTs).

METHODS

The relevant 28 RCTS were retrieved from PubMed searches and reviewed by two reviewers independently.

RESULTS

beta-lactam monotherapy was more effective regarding cure of the infection than clindamycin/aminoglycoside (3177 clinically evaluable patients, fixed effects model, OR = 0.67, 95% CI: 0.55-0.81). The same result was found in several subset analyses. There was no difference in all-cause mortality and attributable-to-infection mortality [2382 intention-to-treat (ITT) patients, fixed effects model, OR = 1.25, 95% CI: 0.74-2.11 and 1976 ITT patients, OR = 1.19, 95% CI: 0.59-2.41, respectively]. There was no difference regarding overall adverse events and ototoxicity (1460 ITT patients, OR = 1.05, 95% CI: 0.80-1.37, and 1404 ITT patients, OR = 3.22, 95% CI: 0.72-14.45, respectively). However, treatment with clindamycin/aminoglycoside was more likely to be associated with nephrotoxicity compared to beta-lactam (3065 ITT patients, OR = 3.7, 95% CI: 2.09-6.57). Clindamycin/aminoglycoside was less likely to be associated with antibiotic-associated diarrhoea compared to beta-lactam (3050 ITT patients, OR = 0.68, 95% CI: 0.46-1.00).

CONCLUSION

The results of our meta-analysis suggest that beta-lactams are more effective in the treatment of intra-abdominal infections compared with clindamycin/aminoglycoside.

Decision-Making Analysis for Selection of Antibiotic Treatment in Intra-Abdominal Infection Using Preference Measurements

BACKGROUND

Antimicrobial therapy of abdominal infections is important to the prognosis of affected patients. The choice of antimicrobial therapy must consider effectiveness, safety, cost, and antibiotic resistance, among numerous factors. However, in reality, decisions are made assuming bioequivalence between regimens, without considering the specific attributes of any particular regimen. The objective was to determine the best antibiotic regimen for patients with community-acquired abdominal infection on the basis of a decision analysis that included effectiveness as well as safety, measured as adverse effects.

METHODS

A decision tree was built using information from a systematic review of the literature on the effectiveness of antimicrobial regimens tested in randomized clinical trials (RCTs) and the frequency and severity of adverse effects. The quality of the articles was assessed with the Oxford criteria for RCTs. The main outcome was preferences reported by surgeons, measured on a numeric scale. Preferences were obtained using a standard survey that reported each adverse effect with its respective intensity, reversibility, sequelae, duration of symptoms, and necessity for change of antibiotic. Each of the surgeons had to assign a value blindly from 0 to 10, where 10 was the most severe. A sensitivity analysis was conducted varying the frequency of adverse effects.

RESULTS

The regimens analyzed were amikacin-metronidazole, amikacin-clindamycin, ciprofloxacin-metronidazole, ampicillin-sulbactam, ceftriaxone-metronidazole, piperacillin-tazobactam, and ertapenem. The perceived severity of adverse effects reported were: Acute neuromuscular blockade (8.0), severe allergic reaction (7.5), ototoxicity (7.4), nephrotoxicity (7.1), antibiotic-associated colitis (7.0), peripheral neuropathy (5.3), general neurological symptoms (4.9), gastrointestinal symptoms (3.1), and other general symptoms (2.6). Favored regimens were ceftriaxone-metronidazole (1.15), ampicillin-sulbactam (1.24), piperacillin-tazobactam (1.27) and ertapenem (1.28). These strategies dominated the other therapeutic schemes. Sensitivity analysis showed no changes in the dominance reported when the frequency of adverse effects was maintained in the known clinical range.

CONCLUSIONS

Antibiotic regimens that contain aminoglycosides are not bioequivalent to those without aminoglycosides when effectiveness and adverse effects are considered simultaneously. Antibiotic regimens that do not use aminoglycosides must be the first line of treatment for abdominal sepsis acquired in the community.

Empiric Treatment of Nosocomial Intra-Abdominal Infections: A Focus on the Carbapenems

BACKGROUND

Serious nosocomial intra-abdominal infections are associated with high morbidity and mortality and represent a substantial drain on healthcare resources. Effective management of this type of infection requires the early use of appropriate, broad-spectrum empiric antimicrobial therapy. The consequences of delayed or inappropriate antimicrobial treatment can be severe-leading to an increased risk of death, re-operation, or prolonged hospitalization. Therefore, it is necessary to begin treatment as soon as possible with the most appropriate regimen, in terms of spectrum, timing, and duration.

METHODS

Review of pertinent English-language literature.

RESULTS

Serious nosocomial intra-abdominal infections require broad-spectrum coverage because of the wide range of possible pathogens, which include difficult-to-treat organisms such as Pseudomonas aeruginosa and Bacteroides spp., and resistant strains of Klebsiella spp., Escherichia coli, and methicillin-resistant Staphylococcus aureus acquired from the hospital flora. The early use of appropriate, broad-spectrum empiric antimicrobial therapy for treating high-risk patients with intra-abdominal infections is considered, and appropriate use of the carbapenems, meropenem, and imipenem/cilastatin, is described.

CONCLUSION

The carbapenems meropenem and imipenem/cilastatin have a spectrum of antimicrobial activity that covers the majority of expected pathogens, including anaerobes, as well as difficult-to-treat and resistant gram-negative strains. Early and appropriate use can reduce mortality and morbidity. Data from published clinical trials support the clinical effectiveness of these two carbapenems in intra-abdominal infections.

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.

Current concepts in peritonitis

Peritonitis is a serious and common infection. Its pathogenesis and microbiology have been well defined. Such risk factors as age, site of infection, physiologic response of the patient, presence of organ dysfunction, and malnutrition may influence the outcome of this disease process. The presence of antibiotic-resistant organisms and delays in operative intervention are also associated with treatment failure and higher mortality. Surgeons have the greatest impact on this disease in their ability to control the source of infection and to administer proper antimicrobial therapy.