Meropenem (1.5 g/day) is as effective as imipenem/cilastatin (2 g/day) for the treatment of moderately severe intra-abdominal infections

The efficacy and safety of eravacycline compared with current clinically common antibiotics in the treatment of adults with complicated intra-abdominal infections: A Bayesian network meta-analysis

Background

Eravacycline is a novel, fully synthetic fluorocycline antibiotic for the treatment of adults with complicated intra-abdominal infections (cIAIs). However, the efficacy and safety of eravacycline compared with current clinically common antibiotics remain unknown.

Objective

This study aims to compare the efficacy and safety of eravacycline and other clinically common antibiotics in China, including tigecycline, meropenem, ertapenem, ceftazidime/avibactam+metronidazole, piperacillin/tazobactam, imipenem/cilastatin, and ceftriaxone+metronidazole, for the treatment of adults with cIAIs and to provide a reference for clinical choice.

Methods

The PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases were electronically searched to collect clinical randomized controlled studies (RCTs) comparing different antibiotics in the treatment of patients with cIAIs from inception to June 1, 2021. Two reviewers independently screened the literature, extracted data, and evaluated the risk of bias in the included studies.

Results

A total of 4050 articles were initially retrieved, and 25 RCTs were included after screening, involving eight treatment therapies and 9372 patients. The results of network meta-analysis showed that in the intention-to-treat (ITT) population, the clinically evaluable (CE) population, and the microbiologically evaluable (ME) population, the clinical response rate of eravacycline was not significantly different from that of the other 7 therapies (P > 0.05). In terms of microbiological response rate, eravacycline was significantly better than tigecycline [tigecycline vs. eravacycline: RR = 0.82, 95%CI (0.65,0.99)], and there was no significant difference between the other 6 regimens and eravacycline (P > 0.05). In terms of safety, the incidence of serious adverse events, discontinuation rate, and all-cause mortality of eravacycline were not significantly different from those of the other 7 treatment therapies (P > 0.05).

Conclusion

Based on the evidence generated by the current noninferiority clinical trial design, the efficacy and safety of eravacycline for the treatment of adults with cIAIs are not significantly different from those of the other 7 commonly used clinical antibiotics in China. In terms of microbiological response rate, eravacycline was significantly better than tigecycline. In view of the severe multidrug-resistant situation in China, existing drugs have difficulty meeting the needs of clinical treatment, and the new antibacterial drug eravacycline may be one of the preferred options for the treatment of cIAIs in adults.

Diagnosis and Management of Intraabdominal Infection: Guidelines by the Chinese Society of Surgical Infection and Intensive Care and the Chinese College of Gastrointestinal Fistula Surgeons

The Chinese guidelines for IAI presented here were developed by a panel that included experts from the fields of surgery, critical care, microbiology, infection control, pharmacology, and evidence-based medicine. All questions were structured in population, intervention, comparison, and outcomes format, and evidence profiles were generated. Recommendations were generated following the principles of the Grading of Recommendations Assessment, Development, and Evaluation system or Best Practice Statement (BPS), when applicable. The final guidelines include 45 graded recommendations and 17 BPSs, including the classification of disease severity, diagnosis, source control, antimicrobial therapy, microbiologic evaluation, nutritional therapy, other supportive therapies, diagnosis and management of specific IAIs, and recognition and management of source control failure. Recommendations on fluid resuscitation and organ support therapy could not be formulated and thus were not included. Accordingly, additional high-quality clinical studies should be performed in the future to address the clinicians' concerns.

Carbapenems vs tigecycline for the treatment of complicated intra-abdominal infections: A Bayesian network meta-analysis of randomized clinical trials

BACKGROUND

Complicated intra-abdominal infections (cIAIs) are common in clinical practice, caused by a mixture of aerobic and anaerobic bacteria, increase the risk of mortality. Carbapenems and tigecycline (TGC) are recommended for antimicrobial therapies for cIAIs.

OBJECTIVE

To compare the effectiveness and safety of different carbapenems vs TGC for the treatment of cIAIs.

METHODS

PubMed, Embase, Medline (via Ovid SP) and Cochrane library databases were systematically searched. We included randomized controlled trials (RCTs) comparing different carbapenems vs TGC for the treatment of cIAIs. The pooled odds ratio (OR) with 95% credible interval (CrI) was calculated by Markov chain Monte Carlo methods. We estimated summary ORs using pairwise and network meta-analysis with random effects.

RESULTS

Fifteen studies involving 6745 participants were included in the analysis. Five different carbapenems and TGC were ultimately evaluated in this study. Although, the efficacy of carbapenems and TGC by ORs with corresponding 95% CrIs had not yet reached statistical differences, the cumulative rank probability indicated that clinical treatment success from best to worst was doripenem (DOPM), meropenem (MEPM), imipenem/cilastatin (IC), biapenem (BAPM), TGC and imipenem/cilastatin/relebactam (ICRB); microbiological treatment success from best to worst was DOPM, MEPM, IC, BAPM, ICRB and TGC. As for the risk of adverse events (AEs), TGC showed higher risk of AEs compared with IC (OR = 1.53, 95% CrI = 1.02-2.41), the remain antibiotic agents from lower to higher was MEPM, IC, BAPM, DOPM, ICRB and TGC. The risk of mortality from lower to higher was BAPM, DOPM, MEPM, IC, TGC and ICRB.

CONCLUSION

No differences in clinical and microbiological outcomes were observed between different carbapenems and TGC. Balancing the evidence for drug efficacy and side effects, DOPM appears to be the best available treatment for cIAIs. Therefore, it is reasonable to consider that DOPM is one of the best carbapenem monotherapy for cIAIs. MEPM and IC was also associated with higher rates of clinical and microbiological treatment success following DOPM. Empiric antimicrobial treatment of patients with cIAIs should be selected in light of the local bacterial epidemiology and patterns of resistance.

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.

Clostridium difficile infection following systemic antibiotic administration in randomised controlled trials: a systematic review and meta-analysis

Antibiotics have been the most important risk factor for Clostridium difficile infection (CDI). However, only data from non-randomised studies have been reviewed. We sought to evaluate the risk for development of CDI associated with the major antibiotic classes by analysing data from randomised controlled trials (RCTs). The PubMed, Cochrane and Scopus databases were searched and the references of selected RCTs were also hand-searched. Eligible studies should have compared only one antibiotic versus another administered systemically. Inclusion of studies comparing combinations of antibiotics was allowed only if the second antibiotic was the same or from the same class or if it was administered in a subset of the enrolled patients who were equally distributed in the two arms. Only a minority of the selected RCTs (79/1332; 5.9%) reported CDI episodes. Carbapenems were associated with more CDI episodes than fluoroquinolones [risk ratio (RR) = 2.44, 95% confidence interval (CI) 1.32-4.49] and cephalosporins (RR = 2.24, 95% CI 1.46-3.42), but not penicillins (RR = 2.53, 95% CI 0.87-7.41). Cephalosporins were associated with more CDIs than penicillins (RR = 2.36, 95% CI 1.32-4.23) and fluoroquinolones (RR = 2.84, 95% CI 1.60-5.06). There was no difference in CDI frequency between fluoroquinolones and penicillins (RR = 1.34, 95% CI 0.55-3.25). Finally, clindamycin was associated with more CDI episodes than cephalosporins and penicillins (RR = 3.92, 95% CI 1.15-13.43). In conclusion, data from RCTs showed that clindamycin and carbapenems were associated with more CDIs than other antibiotics.

Cost-minimization analysis of imipenem/cilastatin versus meropenem in moderate to severe infections at a tertiary care hospital in Saudi Arabia

Aim: The aim of this study was to compare the costs of management of moderate to severe infections in patients treated with imipenem/cilastatin (IC) and meropenem (MEM). Pharmacoeconomic studies in Saudi Arabia are scarce. The current hospital formulary contains 2 carbapenems: IC and MEM. These antibiotics share a similar spectrum of activity. There are conflicting reviews with regard to the relative cost-effectiveness of these two agents. Methods: A retrospective, single-centre cohort study of 88 patients of IC versus MEM in moderate to severe infections was performed, applying cost-minimization analysis (CMA) methods. In accordance with CMA methods, the assumption of equivalent efficacy was first demonstrated by literature retrieved and appraised. Adult patients (⩾18 years old) diagnosed with moderate to severe infections, including skin and skin structure infections (SSIs), sepsis, intra-abdominal infections (IAIs), respiratory tract infections, urinary tract infections (UTIs) and hospital-acquired infections (HAIs), who were prescribed IC 500 mg every six hours intravenously (2 g per day) or MEM 1 g every eight hours (3 g per day), were included in the study. Only direct costs related to the management of the infections were included, in accordance with a payer perspective. Results: Overall there was no difference in the mean total daily costs between IC (SAR 4784.46, 95% CI 4140.68, 5428.24) and MEM (4390.14, 95% CI 3785.82, 4994.45; p = 0.37). A significantly lower medicine acquisition cost per vial of IC was observed when compared to MEM, however there was a significantly higher cost attached to administration sets used in the IC group than the MEM group. Consultation, nursing and physician costs were not significantly different between the groups. No differences were observed in costs associated with adverse drug events (ADEs). Conclusion: This study has shown that while acquisition costs of IC at a dose of 500 mg q6 h may be lower than for MEM 1 g q8 h, mean total costs per day were not significantly different between IC and MEM, indicating that medicine costs are only a small element of the overall costs of managing moderate to severe infections.

Augmented renal clearance, low β-lactam concentrations and clinical outcomes in the critically ill: an observational prospective cohort study

Whilst augmented renal clearance (ARC) is associated with reduced β-lactam plasma concentrations, its impact on clinical outcomes is unclear. This single-centre prospective, observational, cohort study included non-pregnant, critically ill patients aged 18-60 years with presumed severe infection treated with imipenem, meropenem, piperacillin/tazobactam or cefepime and with creatinine clearance (CL(Cr)) ≥60 mL/min. Peak, intermediate and trough levels of β-lactams were drawn on Days 1-3 and 5. Concentrations were deemed 'subthreshold' if they did not meet EUCAST-defined non-species-related breakpoints. Primary and secondary endpoints were clinical response 28 days after inclusion, and ARC prevalence (CL(Cr)≥130 mL/min) and subthreshold and undetectable concentrations, respectively. Logistic regression was used to evaluate associations between ARC, antibiotic concentrations and clinical failure. From 2010 to 2013, 100 patients were enrolled (mean age, 45 years; median CL(Cr) at inclusion, 144.1 mL/min). ARC was present in 64 (64%) of the patients. Most patients received imipenem/cilastatin (54%). Moreover, 86% and 27% of patients had at least one subthreshold or undetectable trough level, respectively. Among imipenem and piperacillin trough levels, 77% and 61% were subthreshold, respectively, but intermediate levels of both antibiotics were largely above threshold. ARC strongly predicted undetectable trough concentrations (OR=3.3, 95% CI 1.11-9.94). A link between ARC and clinical failure (18/98; 18%) was not observed. ARC and subthreshold β-lactam antibiotic concentrations were widespread but were not associated with clinical failure. Larger studies are necessary to determine whether standard dosing regimens in the presence of ARC impact negatively on clinical outcome and antibiotic resistance.

The risk of seizures among the carbapenems: a meta-analysis

OBJECTIVES

A consensus exists among clinicians that imipenem/cilastatin is the most epileptogenic carbapenem, despite inconsistencies in the literature.

METHODS

We conducted a meta-analysis of all randomized controlled trials comparing carbapenems with each other or with non-carbapenem antibiotics to assess the risk of seizures for imipenem, meropenem, ertapenem and doripenem.

RESULTS

In the risk difference (RD) analysis, there were increased patients with seizure (2 per 1000 persons, 95% CI 0.001, 0.004) among recipients of carbapenems versus non-carbapenem antibiotics. This difference was largely attributed to imipenem as its use was associated with an additional 4 patients per 1000 with seizure (95% CI 0.002, 0.007) compared with non-carbapenem antibiotics, whereas none of the other carbapenems was associated with increased seizure. Similarly, in the pooled OR analysis, carbapenems were associated with a significant increase in the risk of seizures relative to non-carbapenem comparator antibiotics (OR 1.87, 95% CI 1.35, 2.59). The ORs for risk of seizures from imipenem, meropenem, ertapenem and doripenem compared with other antibiotics were 3.50 (95% CI 2.23, 5.49), 1.04 (95% CI 0.61, 1.77), 1.32 (95% CI 0.22, 7.74) and 0.44 (95% CI 0.13, 1.53), respectively. In studies directly comparing imipenem and meropenem, there was no difference in epileptogenicity in either RD or pooled OR analyses.

CONCLUSIONS

The absolute risk of seizures with carbapenems was low, albeit higher than with non-carbapenem antibiotics. Although imipenem was more epileptogenic than non-carbapenem antibiotics, there was no statistically significant difference in the imipenem versus meropenem head-to-head comparison.

Meropenem: a review of its use in the treatment of serious bacterial infections

Meropenem (Merrem, Meronem) is a broad-spectrum antibacterial agent of the carbapenem family, indicated as empirical therapy prior to the identification of causative organisms, or for disease caused by single or multiple susceptible bacteria in both adults and children with a broad range of serious infections. Meropenem is approved for use in complicated intra-abdominal infection (cIAI), complicated skin and skin structure infection (cSSSI) and bacterial meningitis (in paediatric patients aged > or = 3 months) in the US, and in most other countries for nosocomial pneumonia, cIAI, septicaemia, febrile neutropenia, cSSSI, bacterial meningitis, complicated urinary tract infection (UTI), obstetric and gynaecological infections, in cystic fibrosis patients with pulmonary exacerbations, and for the treatment of severe community-acquired pneumonia (CAP). Meropenem has a broad spectrum of in vitro activity against Gram-positive and Gram-negative pathogens, including extended-spectrum beta-lactamase (ESBL)- and AmpC-producing Enterobacteriaceae. It has similar efficacy to comparator antibacterial agents, including: imipenem/cilastatin in cIAI, cSSSI, febrile neutropenia, complicated UTI, obstetric or gynaecological infections and severe CAP; clindamycin plus tobramycin or gentamicin in cIAI or obstetric/gynaecological infections; cefotaxime plus metronidazole in cIAI; cefepime and ceftazidime plus amikacin in septicaemia or febrile neutropenia; and ceftazidime, clarithromycin plus ceftriaxone or amikacin in severe CAP. Meropenem has also shown similar efficacy to cefotaxime in paediatric and adult patients with bacterial meningitis, and to ceftazidime when both agents were administered with or without tobramycin in patients with cystic fibrosis experiencing acute pulmonary exacerbations. Meropenem showed greater efficacy than ceftazidime or piperacillin/tazobactam in febrile neutropenia, and greater efficacy than ceftazidime plus amikacin or tobramycin in patients with nosocomial pneumonia. Meropenem is well tolerated and has the advantage of being suitable for administration as an intravenous bolus or infusion. Its low propensity for inducing seizures means that it is suitable for treating bacterial meningitis and is the only carbapenem approved in this indication. Thus, meropenem continues to be an important option for the empirical treatment of serious bacterial infections in hospitalized patients.

Safety profile of meropenem: an updated review of over 6,000 patients treated with meropenem

Meropenem is a broad-spectrum carbapenem antibacterial with potent antimicrobial activity against a broad range of Gram-negative, Gram-positive and anaerobic bacteria. The second parenteral carbapenem to be introduced worldwide, meropenem has been in clinical use since 1994. Two previous safety reviews have established that meropenem has a favourable and acceptable safety profile. This new review was conducted after the approval of meropenem in the US in 2005 for the treatment of patients with complicated skin and skin-structure infections, in addition to the previously approved indications of intra-abdominal infections and paediatric bacterial meningitis. The analysis includes the clinical trial data from the previous safety reviews, updated with expanded experience across a number of serious bacterial infections, including a large international study in patients with skin or skin-structure infections and further experience in patients with intra-abdominal infections and bacterial meningitis. A total of 6154 patients with 6308 meropenem exposures were compared with 4483 patients treated with comparator agents (4593 exposures), and the paediatric population base for which safety data are available has doubled to over 1000 patients. The data presented reinforce the favourable safety profile of meropenem. In general, the incidence and pattern of adverse events occurring with meropenem were similar to those of the first carbapenem, imipenem/cilastatin, and to those of the cephalosporin- and clindamycin-based regimens to which it had been compared. The most common adverse events reported for meropenem were diarrhoea (2.5%), rash (1.4%) and nausea/vomiting (1.2%). No adverse event occurred in more than 3% of patient exposures to meropenem, indicating a low overall frequency of adverse events as well as excellent gastrointestinal tolerability. Furthermore, no unexpected adverse events were identified, and the very low incidence of seizures in patients with meningitis was not considered to be drug related. In infections other than meningitis, the incidence of seizures considered by investigators to be related to meropenem treatment was 0.07%. In the new studies that updated the earlier safety data, no new cases of drug-related seizure were reported for any treatment or patient group (meningitis/non-meningitis infections). In conclusion, meropenem is well tolerated and has good CNS and gastrointestinal tolerability when used for the treatment of serious bacterial infections in a wide range of adult and paediatric patient populations.

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.

Intra-abdominal infections: considerations for the use of the carbapenems

Intra-abdominal infection remains a common and frequently severe medical condition, carrying with it significant morbidity and mortality. These infections are almost always polymicrobial in nature as they are caused by mixed aerobic/anaerobic intestinal flora. Despite substantial improvements in both the medical and surgical management of these infections over the last several decades, there remains an opportunity to further enhance the utilization of adjunctive antibiotic therapy. As a result of the epidemiology and the current resistance profile of the infecting pathogens, the carbapenems represent a class of antibiotics that are considered appropriate for the treatment of severe intra-abdominal infections. This review will discuss the classification and microbiology of these infections and emerging resistance in the pathogens of interest. The review also and focuses on the role of the carbapenems in the management of the constellation of diseases known as intra-abdominal infection.

The Surgical Infection Society guidelines on antimicrobial therapy for intra-abdominal infections: an executive summary

The Surgical Infection Society last published guidelines on antimicrobial therapy for intra-abdominal infections in 1992 (Bohnen JMA, et al., Arch Surg 1992;127:83-89). Since then, an appreciable body of literature has been published on this subject. Therefore, the Therapeutics Agents Committee of the Society undertook an effort to update the previous guidelines, primarily using data published over the past decade. An additional goal of the Committee was to characterize its recommendations according to contemporary principles of evidence-based medicine. To develop these guidelines, the Committee carried out a systematic search for all English language articles published between 1990 and 2000 related to antimicrobial therapy for intra-abdominal infections. This literature was reviewed individually and collectively by the Committee, and categorized according to the type of study and its quality. Additional articles published prior to 1990 were also utilized when necessary. By a process of iterative consensus, the Committee developed provisional guidelines for antimicrobial therapy for intra-abdominal infections based on this evidence. Following extensive review by members of the Society, these guidelines were approved for publication in final form by the Council of the Surgical Infection Society. This executive summary delineates the Society's current recommendations for antimicrobial therapy of patients with intra-abdominal infections. Topics discussed include the selection of patients needing therapeutic antimicrobials, duration of antimicrobial therapy, acceptable antimicrobial regimens, and identification and treatment of higher-risk patients. Guidelines for patient selection and specific antimicrobial regimens were based on relatively good evidence, but those regarding optimal duration of therapy and treatment of higher-risk patients relied mostly on expert opinion, since there was a paucity of high-quality studies on those issues. Relevant areas for future investigation include the safety, convenience, and cost-effectiveness of available antimicrobial regimens for lower-risk patients, and better means for identifying and treating higher-risk patients with intra-abdominal infections.

The Surgical Infection Society guidelines on antimicrobial therapy for intra-abdominal infections: evidence for the recommendations

Revised guidelines for the use of antimicrobial therapy in patients with intra-abdominal infections were recently developed by the Therapeutic Agents Committee of the Surgical Infection Society (Mazuski et al., Surg Infect 2002;3:161-173). These were based, insofar as possible, on evidence published over the past decade. The objective of this document is to describe the process by which the Committee identified and reviewed the published literature utilized to develop the recommendations and to summarize the results of those reviews. English-language articles published between 1990 and 2000 related to antimicrobial therapy for intra-abdominal infections were identified by a systematic MEDLINE search and an examination of references included in recent review articles. If current literature with regard to a specific issue was lacking, relevant articles published prior to 1990 were identified. All prospective randomized controlled trials, as well as other articles selected by the Committee, were evaluated individually and collectively. Data with regard to patient numbers, types of infections, and results of interventions were abstracted. Studies were categorized according to their design, and all included trials were graded according to quality. On the basis of this evidence, the Committee formulated recommendations for antimicrobial therapy for intra-abdominal infections and graded those recommendations. After receiving comments from invited reviewers and the general membership of the Society, the guidelines were finalized and submitted to the Council of the Surgical Infection Society for approval. The final recommendations related to the selection of patients needing therapeutic antimicrobials, acceptable antimicrobial regimens, duration of antimicrobial use, and the identification and treatment of higher-risk patients. Although numerous publications pertaining to these topics were identified, but nearly all of the prospective randomized controlled trials represented comparisons of different antimicrobial regimens for the treatment of intra-abdominal infections. A few prospective trials evaluated the need for therapeutic antimicrobial therapy in patients with peritoneal contamination following abdominal trauma. The quality of these prospective trials was highly variable. Many did not limit enrollment to patients with complicated intra-abdominal infections, lacked blinding of treatment assignment, did not provide a complete description of the criteria used to determine therapeutic success or failure, failed to identify the reasons why patients were excluded from analysis, or did not include an intention-to-treat analysis. For many issues, no prospective randomized controlled trials were encountered, and guidelines had to be formulated using evidence from studies with historical controls or uncontrolled data, or on the basis of expert opinion

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.

Antibiotic regimens for secondary peritonitis of gastrointestinal origin in adults

BACKGROUND

Secondary peritonitis is associated with a high mortality rate and if not treated successfully leads to development of abscesses, severe sepsis and multi-organ failure. Source control and adjunctive antibiotics are the mainstay of treatment. However, no conclusive evidence suggest that one antibiotic regimen is better than any other but at the same time have a lower toxicity.

OBJECTIVES

To ascertain the efficacy and adverse effects of different antibiotic regimens in treating intra-abdominal infections in adults. Outcomes were divided into primary (clinical success and effectiveness in reducing mortality) and secondary (microbiological success, preventing wound infection, intra-abdominal abscess, clinical sepsis, remote infection, superinfection, adverse reactions, duration of treatment required, effectiveness in reducing hospitalised stay, and time to defervescence).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library, Issue 4, 2004), MEDLINE (from 1966 to November 2004), EMBASE (from 1980 to November 2004) and Cochrane Colorectal Cancer Group specialised register SR-COLOCA. Bibliographies of identified studies were screened for further relevant trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic regimens in the treatment of secondary peritonitis in adults were selected. Trials reporting gynaecological or traumatic peritonitis were excluded from this review. Ambiguity regarding suitability of trials were discussed among the review team.

DATA COLLECTION AND ANALYSIS

Six reviewers independently assessed trial quality and extracted data. Data collection was standardised using data collection form to ensure uniformity among reviewers. Statistical analyses were performed using the random effects model and the results expressed as odds ratio for dichotomous outcomes, or weight mean difference for continuous data with 95% confidence intervals.

MAIN RESULTS

Fourty studies with 5094 patients met the inclusion criteria. Sixteen different comparative antibiotic regimens were reported. All antibiotics showed equivocal comparability in terms of clinical success. Mortality did not differ between the regimens. Despite the potential high toxicity profile of regimens using aminoglycosides, this was not demonstrated in this review. The reason for this could be the inherent bias within clinical trials in the form of patient selection and stringency in monitoring drug levels.

AUTHORS' CONCLUSIONS

No specific recommendations can be made for the first line treatment of secondary peritonitis in adults with antibiotics, as all regimens showed equivocal efficacy. Other factors such as local guidelines and preferences, ease of administration, costs and availability must therefore be taken into consideration in deciding the antibiotic regimen of choice. Future trials should attempt to stratify patients and perform intention-to-treat analysis to allow better external validity.

Postoperative enterococcal infection after treatment of complicated intra-abdominal sepsis

BACKGROUND

The prevalence of enterococcal isolation and factors associated with postoperative enterococcal infection remain ill defined.

METHODS

A prospective longitudinal observational study was conducted of consecutive patients with a first episode of intra-abdominal infection and a positive microbiological culture who did or did not develop a postoperative septic complication involving enterococci. The prevalence of initial enterococcal isolation was determined for each focus of infection. Postoperative enterococcal infections were related to whether appropriate (piperacillin--tazobactam), suboptimal (carbapenems) or inappropriate (cefotaxime plus metronidazole) antienterococcal therapy had been administered empirically.

RESULTS

Enterococci were isolated in 42 (21 per cent) of the 200 patients investigated. The isolation rates were 11 per cent for community-acquired peritonitis, 50 per cent for postoperative peritonitis and 23 per cent for intra-abdominal abscesses of both origins. No enterococci were isolated from 49 patients with perforated appendicitis. Independent factors for postoperative enterococcal infection were type of intra-abdominal infection (P = 0.006), Acute Physiology And Chronic Health Evaluation (APACHE) II score greater than 12 (P = 0.04) and inappropriate empirical antibiotic cover (P = 0.05). Postoperative enterococcal infections were associated with a high mortality rate (21 versus 4 per cent; P < 0.0007).

CONCLUSION

Enterococci are frequently isolated from intra-abdominal infections of non-appendiceal origin and are often involved in postoperative infectious complications, particularly peritonitis. Empirical antibiotic therapy covering Enterococcus faecalis should be contemplated in some circumstances.

Use of Etests with carbapenems for Gram-negative rods producing beta-lactamases

The in vitro activity of imipenem and meropenem on strains of Gram-negative rods producing extended-spectrum beta-lactamase (ESBL) and inducible beta-lactamase (IBL) was studied using the Etest. In all, 185 strains from the surgical intensive care units of four different hospitals were looked at over 2 years. Of these, 94 were ESBL producers and 91 were IBL positive. The in vitro sensitivities of imipenem and meropenem were 89.7 and 95.1%, respectively, against all strains. The imipenem and meropenem sensitivities of Klebsiella spp. were 98.4 and 100%, respectively, but imipenem resistance (21.6%) in Pseudomonas aeruginosa strains was higher than that of meropenem (10.8%).

Antibiotic prophylaxis and treatment of surgical abdominal sepsis

The incidence of surgical abdominal sepsis is related to the operation, patient and skill of the surgeon, ranging from <2-3% for laparoscopic cholecystectomy to >35-40% in overt peritonitis. Aged, obese, diabetic, neoplastic, acute patients have the highest incidence of sepsis. Antibiotic prophylaxis significantly reduces the incidence of postoperative infections for Class II and II operations. The proper timing (30-60 min before incision), choice of antibiotic (related to possible pathogens) and correct duration are essential. Ultra-short prophylaxis (only one administration) may be effective in most class II procedures and a cephalosporin can be used. Class II operations (colorectal) may require a booster dose soon after surgery or during surgery exceeding 3 h. The most effective regimen may include: ampicillin, clindamycin, I- II- III- or IV-generation cephalosporins, amoxycillin, aminoglycosides, metronidazole have been used alone and in combination. Combination prophylaxis should be active against aerobic and anaerobic bacteria. Treatment of surgical abdominal sepsis may be primary, seconday or tertiary. Surgery should remove the pathologic lesion, and antibiotics reduce the general effects of sepsis and infectious complications. This article presents information on the general rules for correct prophylaxis and treatment.

Meropenem: an updated review of its use in the management of intra-abdominal infections

Meropenem is a carbapenem antibacterial agent with a broad spectrum of activity which encompasses gram-negative, gram-positive and anaerobic bacteria. Like other carbapenems, meropenem is stable against chromosomal and extended-spectrum beta-lactamases. In patients with moderate to severe intra-abdominal infections, empirical monotherapy with meropenem achieved clinical response rates ranging from 91 to 100% in 7 randomised comparative trials. Efficacy rates were similar to those of imipenem/cilastatin (94 to 97%), clindamycin plus tobramycin (93%) and, overall, to cefotaxime plus metronidazole (75 to 100%), although there were differences between trials versus this combination regimen. According to limited data, meropenem also achieved clinical response rates of over 80% in patients with severe intra-abdominal infections. Meropenem is well tolerated, the most common adverse events being diarrhoea, rash, nausea/vomiting and inflammation at the injection site which are reported in <2.5% of patients each. Meropenem also has an improved CNS tolerability profile compared with imipenem/cilastatin.

CONCLUSIONS

Extensive comparative clinical data demonstrate that meropenem can be used effectively as empirical monotherapy in moderate to severe intra-abdominal infections. It also shows potential in the most severe forms of infection, although experience in this infection type remains limited. Compared with standard combination regimens, meropenem offers the benefits of ease of administration without the need for monitoring. It also offers improved CNS tolerability compared with imipenem/cilastatin with the option of a higher maximum dosage, which may be a particular advantage in patients with severe intra-abdominal infections.