Antibiotic treatment for surgical peritonitis

Prevalence of fecal carriage of antibiotic-resistant bacteria in patients with acute surgical abdominal infections

OBJECTIVE

Antibiotic resistance is increasing worldwide. The aims of the current study were to determine the fecal carriage of antibiotic-resistant bacteria and antibiotic treatment in surgical patients admitted to hospital due to acute intra-abdominal infections.

MATERIALS AND METHODS

Eight Swedish surgical units participated in this prospective multicenter investigation. Rectal swabs were obtained on admission to hospital. Cultures were performed on chromogenic agar and antibiotic susceptibility testing was performed using the disk diffusion method. Extended-spectrum beta-lactamase (ESBL)-phenotype was confirmed by Etest.

RESULTS

Rectal samples were obtained and analyzed from 208 patients with intra-abdominal surgical infections. Surgery was performed in 134 patients (65%). Cephalosporins were the most frequently used empirical antibiotic therapy. The highest rates of resistance among Enterobacteriaceae were detected for ampicillin (54%), tetracycline (26%), cefuroxime (26%) and trimethoprim-sulfamethoxazole (20%). The prevalence of decreased susceptibility (I + R) for the other antibiotics tested was for ciprofloxacin 20%, piperacillin-tazobactam 17%, cefotaxime 14%, ertapenem 12%, gentamicin 3% and imipenem 0%. ESBL-producing Enterobacteriaceae were found in samples from 10 patients (5%). Three patients had five E. coli isolates producing AmpC enzymes.

CONCLUSIONS

This study shows a high rate of resistance among Enterobacteriaceae against antibiotics which are commonly used in Sweden and should have implications for the future choice of antibiotics for surgical patients.

Microbiological profile and antimicrobial susceptibility in surgical site infections following hollow viscus injury

INTRODUCTION

The purpose of this study was to assess the microbiological profile, antimicrobial susceptibility, and adequacy of the empiric antibiotic therapy in surgical site infections (SSI) following traumatic hollow viscus injury (HVI).

METHODS

This is a retrospective study of patients admitted with an HVI from March 2003 to July 2009. SSI was defined as a wound infection or intra-abdominal collection confirmed by positive cultures and requiring percutaneous or surgical drainage.

RESULTS

A total of 91 of 667 (13.6%) patients with an HVI developed an SSI confirmed by positive culture. Mean age was 33.0 +/- 14.1 years, mean Injury Severity Score (ISS) was 17.7 +/- 9.6, 91.2% were male, and 80.2% had sustained penetrating injuries. The SSI consisted of 65 intra-abdominal collections and 26 wound infections requiring intervention. The most commonly isolated species in the presence of a colonic injury was Escherichia coli (64.7%), Enterococcus spp. (41.2%), and Bacteroides (29.4%), and in the absence of a colonic perforation, Enterococcus spp. and Enterobacter cloacae (both 38.9%). Susceptibility rates of E. coli and E. cloacae, respectively, were 38% and 8% for ampicillin/sulbactam, 82% and 4% for cefazolin, 96% and 92% for cefoxitin, with both 92% to piperacillin/tazobactam, and 100% to ertapenem. The initial empirical antibiotic therapy adequately targeted the pathogens in 51.6% of patients who developed an SSI.

CONCLUSION

The distribution of the microorganisms isolated from SSIs differed significantly according to whether or not a colonic injury was present. Empiric antibiotic treatment was inadequate in upwards of 50% of patients who developed an SSI. Further investigation is warranted to determine the optimal empiric antibiotic regimen for reducing the rate of postoperative SSI.

Peritoneal fluid culture in appendicitis: review in changing times

Appendicectomy is one of the commoner operations with a lifetime risk as high as 12% or 23% in males or females, respectively. Since the 1940s intra-operative intra-peritoneal swabs have commonly been taken from the appendix site, the spectrum of infecting organisms and their antibiotic sensitivity may be gauged from the culture results. This approach remains common but in recent years, studies have claimed that intra-peritoneal swabs are unnecessary; however, they relied upon retrospective patient groups predating wider use of laparoscopic appendicectomy, increasing numbers of immunocompromised people at risk of appendicitis and the clinical/medicolegal significance of increasing risk of antibiotic-associated Clostridium difficile colitis. Therefore, a key-word literature research was done to identify relevant publications from 1930 to June 2009. Newer features relating to intra-peritoneal swabs in appendicectomy have been discussed against this background information for periabdominal appendicectomy with or without appendicular perforation, laparoscopic appendicectomy and appendicectomy in the growing numbers of immunocompromised patients. All studies questioning the use of intra-peritoneal swabs were open, non-randomised, and retrospective with incompletely matched control groups, non-standardised swab collection techniques, and consequently lacked power to inform surgical practice. They concluded that an appropriately powered randomised, blinded, prospective, controlled clinical trial is needed to test for absolute efficacy in the use of peritoneal swabs in patient management. Until controlled trial data becomes available, it may be wise to continue peritoneal swabs at least in high-risk patients to decrease clinical and medicolegal risk.

Antibiotic susceptibility of intra-abdominal infection isolates from Indian hospitals during 2008

A total of 542 clinical isolates of aerobic Gram-negative bacilli from intra-abdominal infections were collected during 2008 from seven hospitals in India participating in the Study for Monitoring Antimicrobial Resistance Trends (SMART). Isolates were from various infection sources, the most common being gall bladder (30.1 %) and peritoneal fluid (31.5 %), and were mostly hospital-associated isolates (70.8 %) as compared to community-acquired (26.9 %). The most frequently isolated pathogens were Escherichia coli (62.7 %), Klebsiella pneumoniae (16.7 %) and Pseudomonas aeruginosa (5.3 %). Extended-spectrum beta-lactamase (ESBL) rates in E. coli and K. pneumoniae were very high, at 67 % and 55 %, respectively. Most isolates exhibited resistance to one or more antibiotics. The most active drugs were generally ertapenem, imipenem and amikacin. However, hospital-acquired isolates in general, as well as ESBL-positive isolates, exhibited lower susceptibilities than community-acquired isolates. Further surveillance monitoring of intra-abdominal isolates from India is recommended.

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.

Epidemiology, management, and prognosis of secondary non-postoperative peritonitis: a French prospective observational multicenter study

BACKGROUND

Despite improvements in treatment, secondary peritonitis still is associated with high morbidity and mortality rates. Better knowledge of real-life clinical practice might improve management.

METHODS

Prospective, observational study (January-June 2005) of 841 patients with non-postoperative secondary peritonitis.

RESULTS

Peritonitis originated in the colon (32% of patients), appendix (31%), stomach/duodenum (18%), small bowel (13%), or biliary tract (6%). Most patients (78%) presented with generalized peritonitis and 26% with severe peritonitis (Simplified Acute Physiology Score [SAPS] II score>38). Among the 841 patients, 27.3% underwent laparoscopy alone; 11% underwent repeat surgery, percutaneous drainage, or both. A SAPS II score>38 and the presence of Enterococcus spp. were predictive of abdominal and non-surgical infections (odds ratio [OR]=1.84; p=0.013 and OR=2.93; p<0.0001, respectively). A SAPS II score>38 also was predictive of death (OR=10.5; p<0.0001). The overall mortality rate was high (15%). Patients receiving inappropriate initial antimicrobial therapy had significantly higher morbidity and mortality rates than patients receiving appropriate therapy (44 vs. 30%; p=0.004 and 23% vs. 14%; p=0.015, respectively). The SAPS II score and rates of severe peritonitis, morbidity, and mortality were significantly lower in patients with appendiceal peritonitis.

CONCLUSIONS

Patients with non-postoperative peritonitis should be considered high risk and should receive appropriate initial therapy. The presence of Enterococcus spp. in peritoneal cultures significantly increased morbidity but not the mortality rate. Appendiceal peritonitis that was less severe and had a better prognosis than peritonitis originating in other sites should be considered a special case in future studies.

Clinical and microbiological profiles of community-acquired and nosocomial intra-abdominal infections: results of the French prospective, observational EBIIA study

OBJECTIVES

The EBIIA (Etude épidémiologique Bactério-clinique des Infections Intra-Abdominales) study was designed to describe the clinical, microbiological and resistance profiles of community-acquired and nosocomial intra-abdominal infections (IAIs).

PATIENTS AND METHODS

From January to July 2005, patients undergoing surgery/interventional drainage for IAIs with a positive microbiological culture were included by 25 French centres. The primary endpoint was the epidemiology of the microorganisms and their resistance to antibiotics. Multivariate analysis was carried out using stepwise logistic regression to assess the factors predictive of death during hospitalization.

RESULTS

Three hundred and thirty-one patients (234 community-acquired and 97 nosocomial) were included. The distribution of the microorganisms differed according to the type of infection. Carbapenems and amikacin were the most active agents in vitro against Enterobacteriaceae in both community-acquired and nosocomial infections. Against Pseudomonas aeruginosa, amikacin, imipenem, ceftazidime and ciprofloxacin were the most active agents in community-acquired infections, while imipenem, cefepime and amikacin were the most active in nosocomial cases. Against the Gram-positive bacteria, vancomycin and teicoplanin were the most active in both infections. Against anaerobic bacteria, the most active agents were metronidazole and carbapenems in both groups. Empirical antibiotic therapy adequately targeted the pathogens for 63% of community-acquired and 64% of nosocomial peritonitis. The presence of one or more co-morbidities [odds ratio (OR) = 3.17; P = 0.007], one or more severity criteria (OR = 4.90; P < 0.001) and generalized peritonitis (OR = 3.17; P = 0.006) were predictive of death.

CONCLUSIONS

The principal results of EBIIA are a higher diversity of microorganisms isolated in nosocomial infections and decreased susceptibility among these strains. Despite this, the adequacy of treatment is comparable in the two groups.

Inflammation and the host response to injury, a large-scale collaborative project: patient-oriented research core--standard operating procedures for clinical care VII--Guidelines for antibiotic administration in severely injured patients

When the clinical decision to treat a critically ill patient with antibiotics has been made, one must attempt to identify the site of infection based on clinical signs and symptoms, laboratory or diagnostic radiology studies. Identification of site requires, examination of patient, inspection of all wounds, chest radiograph, and calculation of clinical pulmonary infection score if ventilated, obtaining blood cultures, urinalysis, and line change if clinical suspicion of central venous catheter (CVC) source. If it is impossible to identify site, obtain cultures from all accessible suspected sites and initiate empiric, broad spectrum antibiotics. If likely site can be identified answer these questions: Is intra-abdominal site suspected? Is pulmonary source of infection suspected? Is skin, skin structure or soft tissue site suspected? If yes, does the patient have clinical signs suspicion for necrotizing soft tissue infection (NSTI)? Is a CVC infection suspected? Risk factors for more complicated infections are discussed and specific antibiotic recommendations are provided for each type and severity of clinical infection. Decision to continue, discontinue and/or alter antibiotic/antimicrobial treatment should be based on the clinical response to treatment, diagnostic or interventional findings, and culture and sensitivity data, bearing in mind that not all patients with infections will have positive cultures because of limitations of specimen handling, microbiology laboratory variations, time between specimen acquisition and culture, or presence of effective antibiotics at the time that specimens were obtained. It should also be noted that not all patients with increased temperature/WBC have an infection. Discontinuation of antibiotics is appropriate if cultures and other diagnostic studies are negative.

Intra-operative culture swabs in acute appendicitis: a waste of resources

INTRODUCTION

Antibiotics gained a place in the management of acute appendicitis when the bacterial aetiology was demonstrated. Culture swabs were obtained routinely during appendicectomies to guide antibiotic use. Although current antimicrobial therapy use has become prophylactic, empirical and broad spectrum, this age-old practice still remains. Our study questions the value of this traditional practice.

MATERIALS AND METHODS

All adult and paediatric patients undergoing emergency appendicectomy over three years were retrospectively reviewed. Microbiology and appendix histology reports were retrieved. Occurrence of infective post-operative morbidity was recorded via hospital notes.

RESULTS

A total of 652 appendectomies (age 1 month to 81 years, median 20 years) were performed in a 36 month period. Four hundred and thirty-five/six hundred and fifty-two (66.7%) had intra-operative swabs taken. One hundred and forty/four hundred and thirty-five (32%) revealed presence ofa pathogens. One hundred and twenty-two/four hundred and thirty-five (28%) were sensitive to broad spectrum empirical antibiotics and only 18/435 (4.1%) cultured resistant strains. Forty-two/six-hundred and fifty-two (6.4%) patients had postoperative infective complications. Twenty-nine/forty-two (68%) had a different organism responsible for this complication. The highest proportion of positive cultures and post-operative infective complications was observed in the extremes of ages (< 10 and > 50 years) and in gangrenous appendicitis.

CONCLUSION

A majority of intra-operative swabs were negative or isolated commensal flora. Pathogens causing postoperative morbidity were frequently different from those isolated intra-operatively. None of the patients had a change of management based on the swab results. Hence routine intra-peritoneal swabs remains of little clinical value.

Economic consequences of failure of initial antibiotic therapy in hospitalized adults with complicated intra-abdominal infections

BACKGROUND

Initial antibiotic therapy in hospitalized adults with complicated intra-abdominal infection (cIAI) usually is empiric. We explored the economic consequences of failure of such therapy in this patient population.

METHODS

Using a large U.S. multi-institutional database, we identified all hospitalized adults admitted between April 1, 2003, and March 31, 2004; who had any cIAI; underwent laparotomy, laparoscopy, or percutaneous drainage of an intra-abdominal abscess ("surgery"); and received intravenous (IV) antibiotics. Initial therapy was characterized in terms of all IV antibiotics received, on the day of or one day before initial surgery. Antibiotic failure was designated on the basis of the need for reoperation or receipt of other IV antibiotics postoperatively. Switches to narrower spectrum agents and changes in regimen prior to discharge with no other evidence of clinical failure were not counted as antibiotic failures. Using multivariable linear regression, duration of IV antibiotic therapy, hospital length of stay, and total inpatient charges were compared between patients who did and did not fail initial therapy. Mortality was compared using multivariable logistic regression.

RESULTS

Among 6,056 patients who met the study entrance criteria, 22.4% failed initial antibiotic therapy. Patients who failed received an additional 5.6 days of IV antibiotic therapy (10.4 total days [95% confidence interval 10.1, 10.8] days vs. 4.8 total days [4.8, 4.9] for those not failing), were hospitalized an additional 4.6 days (11.6 total days [11.3, 11.9] vs. 6.9 total days [6.8, 7.0], respectively), and incurred $6,368 in additional inpatient charges ($16,520 [$16,131, $16,919] vs. $10,152 [$10,027, $10,280]) (all, p < 0.01). They also were more likely to die in the hospital (9.5% vs. 1.3%; multivariable odds ratio 3.58 [95% confidence interval 2.53, 5.06]).

CONCLUSIONS

Failure of initial IV antibiotic therapy in hospitalized adults with cIAIs is associated with longer hospitalization, higher hospital charges, and a higher mortality rate.

Treatment of severe sepsis secondary to mycobacterium avium-intracellulare with recombinant human activated protein C

BACKGROUND

Mycobacterium avium-intracellulare (MAI) is a well-described pathogen in patients with acquired immune deficiency syndrome (AIDS). However, peritonitis and severe sepsis as a complication of disseminated MAI is rare. We report a case that represents the first successful use of recombinant human activated protein C (rhAPC) in the treatment of severe sepsis secondary to mycobacterial infection and only the second reported case of MAI peritonitis with no known predisposing factor other than AIDS.

METHODS

Case report and review of the pertinent literature.

RESULTS

A 36-year-old man with AIDS presented to the emergency department with acute-onset right-sided abdominal pain, fever, and chills. Abdominal computed tomography revealed multiple rim-enhancing fluid collections. Despite immediate surgical drainage and debridement and appropriate antimicrobial therapy targeting the non-tuberculous acid-fast bacilli found in intraperitoneal fluid, the patient developed severe sepsis and septic shock. Clinical improvement occurred after infusion of recombinant human activated protein C (rhAPC) and specific antimicrobial chemotherapy directed against MAI.

CONCLUSIONS

Treatment with rhAPC decreases the mortality rate of bacterial sepsis of abdominal origin and may confer a similar benefit in the treatment of abdominal mycobacterial sepsis.

[Bacterial cultures and empirical antimicrobial therapy for community-acquired secondary peritonitis]

Surgeons and anesthetists are frequently confronted with community-acquired secondary peritonitis. We summarize literature results and consensus conferences concerning the types of bacteriologic sampling and cultures and the empiric choice of an antibiotic regimen based on the probable pathogens encountered in community-acquired secondary peritonitis. These studies leave some doubt as to the necessity for routine blood cultures and the need for anaerobic cultures of peritoneal fluid. No one disputes the need for broad spectrum antibiotic therapy, but there is no consensus regarding one, two, or three drug antibiotic regimens or whether an aminoglycoside is an essential part of the recipe. Duration of antibiotic therapy is still a subject of controversy with recommendations varying from 24 hours to 10 days. The need for antibiotics with activity against enterococcus and the need for systematic antifungal therapy when fungal growth is noted in the peritoneal fluid remain undefined. These uncertainties underline the need for treating physicians within each establishment to elaborate a written consensus of antibiotic therapy.

A prospective, double-blind, multicenter, randomized trial comparing ertapenem 3 vs >or=5 days in community-acquired intraabdominal infection

Severe secondary peritonitis is diagnosed in only 20-30% of all patients, but studies to date have persisted in using a standard fixed duration of antibiotic therapy. This prospective, double-blind, multicenter, randomized clinical study compared the clinical and bacteriological efficacy and tolerability of ertapenem (1 g/day) 3 days (group I) vs >or=5 days (group II) in 111 patients with localized peritonitis (appendicitis vs non-appendicitis) of mild to moderate severity, requiring surgical intervention. In evaluable patients, the clinical response as primary efficacy outcome were assessed at the test-of-cure 2 and 4 weeks after discontinuation of antibacterial therapy. Ninety patients were evaluable. In groups I and II, 92.9 and 89.6% of patients were cured, respectively; 95.3% in group I and 93.7% in group II showed eradication. These differences were not statistically significant. The most frequent bacteria recovered were Escherichia coli and Bacteroides fragilis. A wound infection developed in seven patients (7.7%) and an intraabdominal infection in one patient (1.1%). There was a low frequency of drug-related clinical or laboratory adverse effects in both groups. Our study demonstrated that, in patients with localized community-acquired intraabdominal infection, a 3-day course of ertapenem had the same clinical and bacteriological efficacy as a standard duration.

Prospective evaluation of virulence factors of enterococci isolated from patients with peritonitis: impact on outcome

The objective of this study was to evaluate the prevalence of 4 virulence factors (VFs) of enterococci (cytolysin [cyl], gelatinase [gel], aggregation substance [agg], and enterococcal surface protein [esp]) and their relationship to outcome in patients with generalized peritonitis in a prospective cohort study. VF expression in each strain was assessed by polymerase chain reaction assay with specific primers. Outcome of the patients was recorded. Ninety-nine strains of Enterococcus were obtained from the peritoneal fluid of 81 patients. Fifty-eight patients had at least 1 strain bearing [cyl] (13.1% of the strains), [gel] (50.5% of the strains), [agg] (40.4% of the strains), and [esp] (34.3% of the strains). The presence of VF of Enterococcus was independently associated with mortality: odds ratio, 5.5; 95% confidence interval, 1.3-28.1. In conclusion, VF accounted for 72% of the patients with enterococci isolated from the peritoneal fluid and was independently associated with mortality in severe peritonitis.

Consequences of inappropriate initial empiric parenteral antibiotic therapy among patients with community-acquired intra-abdominal infections in Spain

To assess the association between inappropriate antibiotic therapy and clinical outcomes for complicated community-acquired intra-abdominal infections in Spain, patient records from October 1998 to August 2002 in 24 hospitals were reviewed. Initial empiric therapy was classified appropriate if all isolates were sensitive to at least 1 of the antibiotics administered. Multivariate analyses were performed to assess associations between appropriateness of therapy and patient outcomes. Healthcare resource use was measured as hospital length of stay (LOS) and d on intravenous antibiotic therapy. A total of 425 patients were included. Of these, 387 (91%) received appropriate initial empiric therapy. Patients on inappropriate therapy were less likely to have clinical success (79% vs 26%, p<0.001), more likely to require additional antibiotic therapy (40% vs 7%, p<0.01) and more likely to be re-hospitalized within 30 d of discharge (18% vs 3%, p<0.01). Multivariate analyses also showed that inappropriate therapy was associated with an almost 16% increase in LOS (p<0.05) and 26% in d of intravenous antibiotic therapy compared with appropriate therapy (p<0.05). Inappropriate initial antibiotic therapy was associated with a significantly higher proportion of unsuccessful patient outcomes (including death, re-operation, re-hospitalization or additional parental antibiotic therapies), increased length of stay and length on therapy.

Bacteriologic and therapeutic considerations in intra-abdominal surgical infections

The most important factor in the treatment of intra-abdominal infections are early diagnosis and prompt surgical intervention while antibiotics play a secondary role. The goals of surgical procedures should be to stop peritoneal contamination, to debride necrotic tissue, to remove debris and foreign bodies and to drain any pus collection. Antibiotics should be initiated before surgery and they must encompass both colonic aerobes and anaerobes including Bacteroides fragilis group but not necessary Enterococcus sp. Antibacterial agents with pure activity against anaerobes include chloramphenicol, clindamycin and the nitroimidazoles while ampicillin/sulbactam, amoxicillin/clavulanate, ticarcillin/clavulanate, cefoxitin, cefotetan, ceftizoxime imipenem/cilastatin, meropenem and some advanced quinolones like sparfloxacin, represent a single drug to cover both aerobic and anaerobic microflora. Although almost all clinical trials usually result in a 90% efficacy rate, the final outcome is dependant on the stage of the infection (early versus late), sepsis score, underlying diseases and the applied surgical procedures. On the other hand the choice of antibiotic(s) must be influenced by its toxicity, profiles local nosocomial susceptibility patterns, resistance inducing ability and price.

Introduction: the challenge of multiresistance

Antibiotic resistance is selected by antibiotic usage, which, in hospitals at least, is likely to increase driven by changes in demography, international development and advances elsewhere in medicine. Maintaining mankind's ability to treat infection therefore depends on better utilisation of present antimicrobials--better regimens as well as less unnecessary use--and on better infection control, but also on the development of new vaccines and antibiotics. Current developments include a raft of new agents active against meticillin-resistant Staphylococcus aureus (MRSA), but few that offer any advance against Gram-negative organisms. One that does have increased anti-Gram-negative activity, compared with earlier analogues, is tigecycline, a glycylcycline derivative of minocycline.

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.

Value of intraoperative abdominal cavity culture in appendicectomy: a retrospective study

Appendicectomy is one of the most common surgical emergency procedures. Intraperitoneal culture during appendicectomy is routine practice in some hospitals, while some surgeons advocate abandoning this routine. The aim of our study is to determine the value of intraoperative abdominal cavity culture and its impact on the patient management. Retrospective analysis was performed on 498 patients who underwent appendicectomy over 2.5-year period. The median of the postoperative hospital stay was 2 days, while the median time taken to receive culture results was 3 days. A positive culture was found in 42.6%. Approximately 42.7% of the patients were discharged from the hospital before receiving the culture results. The culture and sensitivity results altered the antibiotic regimen in one patient (0.85%). Intraoperative abdominal cavity culture results were seldom used for clinical management in patients with acute appendicitis. The traditional surgical practice of routinely culturing peritoneal fluid in these patients should be abandoned.

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.

Peritonitis - the Western experience

Peritonitis is a common surgical emergency. This manuscript will provide an overview of recent developments in the management of peritonitis in the Western world. Emphasis is placed on the emergence of new treatments and their impact of outcomes.

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

Randomized controlled trial of moxifloxacin compared with piperacillin-tazobactam and amoxicillin-clavulanate for the treatment of complicated intra-abdominal infections

OBJECTIVE

To compare the safety and efficacy of sequential intravenous (IV) to oral (PO) moxifloxacin treatment against a standard antimicrobial regimen of IV piperacillin-tazobactam followed by PO amoxicillin-clavulanate for the treatment of adults with complicated intra-abdominal infection (cIAI).

SUMMARY BACKGROUND DATA

cIAIs are commonly due to mixed aerobic and anaerobic bacteria and require both source control and broad-spectrum antibiotic therapy.

METHODS

A prospective, double-blind, randomized, phase III comparative trial. Patients with cIAI were stratified by disease severity (APACHE II score) and randomized to either IV/PO moxifloxacin (400 mg q24 hours) or comparator (IV piperacillin-tazobactam [3.0/0.375 g q6 hours] +/- PO amoxicillin-clavulanate [800 mg/114 mg q12 hours]), each for 5 to 14 days. The primary efficacy variable was clinical cure rate at the test-of-cure visit (days 25-50). Bacteriologic outcomes were also determined.

RESULTS

: Of 656 intent-to-treat patients, 379 (58%) were valid to assess efficacy (183 moxifloxacin, 196 comparator). Demographic and baseline medical characteristics were similar between the 2 groups. Clinical cure rates at test-of-cure were 80% (146 of 183) for moxifloxacin versus 78% (153 of 196) for comparator (95% confidence interval, -7.4%, 9.3%). The clinical cure rate at test-of-cure for hospital-acquired cIAI was higher with moxifloxacin (82%, 22 of 27) versus comparator (55%, 17 of 31; P = 0.05); rates were similar for community-acquired infections (80% [124 of 156] versus 82% [136 of 165], respectively). Bacterial eradication rates were 78% (117 of 150) with moxifloxacin versus 77% (126 of 163) in the comparator group (95% confidence interval, -9.9%, 8.7%).

CONCLUSIONS

Once daily IV/PO moxifloxacin monotherapy was as least as effective as standard IV piperacillin-tazobactam/PO amoxicillin-clavulanate dosed multiple times daily for the treatment of cIAIs.

Estudio controlado con grupos paralelos y abierto de la eficacia clínica y microbiológica de piperacilina-tazobactam frente a metronidazol más gentamicina en cirugía colorrectal urgente

INTRODUCTION

Antibiotic treatment is an important element in infection control after urgent abdominal surgery. The aim of this study was to determine the therapeutic efficacy of piperacillin-tazobactam versus a combination of 2 antibiotics (metronidazole and gentamicin) in patients undergoing urgent appendicular and/or colorectal surgery.

PATIENTS AND METHOD

The study period comprised December 1998 to December 2002. A total of 183 patients who required urgent surgery for colon disease and/or severe acute appendicitis were prospectively and randomly included. Patients were randomly distributed in 2 groups. Group A received piperacillin-tazobactam (4/0.5/8 h/i.v.) and group B received metronidazole (500 mg/i.v./8 h) plus gentamicin (5 mg/kg/i.v./24 h). Treatment was started between 30 and 60 minutes prior to surgery and was continued for at least 3 days.

RESULTS

The incidence of wound infection in patients who underwent surgery for colon disease and acute appendicitis was lower when they were treated with piperacillin-tazobactam (P< .05). The incidence of intraperitoneal abscess in the group of patients who underwent surgery for severe acute appendicitis was lower when they were treated with piperacillin-tazobactam. Microbiological analyses revealed that there was a predominance of infection due to Escherichia coli.

CONCLUSIONS

The association of piperacillin-tazobactam was more effective than that of metronidazole and gentamicin in the prevention and treatment of local infection in the treated groups. Therapeutic failure was mainly related to the presence of gram-negative bacteria.

Importance of appropriateness of empiric antibiotic therapy on clinical outcomes in intra-abdominal infections

Objectives:The objective of this study is to describe the frequency of inappropriate empirical antibiotic therapy in secondary intra-abdominal infection and to identify the possible relationship between inappropriateness and some clinical outcomes.

Methods:A retrospective descriptive multicenter study was conducted using hospital secondary databases developed at two university hospitals located in northeast Spain. Participants were patients 18 years of age or older who were diagnosed with community-acquired intra-abdominal infections between January 1, 1998, and December 31, 2000, identified through computerized patient records using ICD-9 codes. Appropriateness of empirical treatment was defined according to the recommendations of the literature. The clinical outcome of each patient was classified as one of the following: (i) resolved with initial therapy, (ii) required second-line antibiotics, (iii) required re-operation, or (iv) in-hospital death. The Fisher's exact test or the Chi-squared test for categorical variables and thet-test or Mann–Whitney test for continuous variables were used for comparing groups. Conditional logistic and linear regression analyses were also applied.

Results:Of 376 cases, 51 cases (13.6 percent, 95 percent confidence interval, 10–17 percent) received inappropriate empirical antibiotic therapy according to the scientific literature. Inappropriate initial empirical treatment was significantly associated with the need for a second line of antibiotics (p<.001), although not with re-operation, mortality, or length of hospitalization.

Conclusions:Approximately 14 percent of the patients received inappropriate empirical antibiotic treatment. Worse clinical outcomes consistently were observed in the group of patients receiving inappropriate empirical treatment. The appropriateness of antibiotic treatment for a given infection, in light of the availability of clearly defined clinical guidelines is an easily evaluated aspect of the quality of care.

Critical issues in the clinical management of complicated intra-abdominal infections

Intra-abdominal infections differ from other infections through the broad variety in causes and severity of the infection, the aetiology of which is often polymicrobial, the microbiological results that are difficult to interpret and the essential role of surgical intervention. From a clinical viewpoint, two major types of intra-abdominal infections can be distinguished: uncomplicated and complicated. In uncomplicated intra-abdominal infection, the infectious process only involves a single organ and no anatomical disruption is present. Generally, patients with such infections can be managed with surgical resection alone and no antimicrobial therapy besides perioperative prophylaxis is necessary. In complicated intra-abdominal infections, the infectious process proceeds beyond the organ that is the source of the infection, and causes either localised peritonitis, also referred to as abdominal abscess, or diffuse peritonitis, depending on the ability of the host to contain the process within a part of the abdominal cavity. In particular, complicated intra-abdominal infections are an important cause of morbidity and are more frequently associated with a poor prognosis. However, an early clinical diagnosis, followed by adequate source control to stop ongoing contamination and restore anatomical structures and physiological function, as well as prompt initiation of appropriate empirical therapy, can limit the associated mortality. The biggest challenge with complicated intra-abdominal infections is early recognition of the problem. Antimicrobial management is generally standardised and many regimens, either with monotherapy or combination therapy, have proven their efficacy. Routine coverage against enterococci is not recommended, but can be useful in particular clinical conditions such as the presence of septic shock in patients previously receiving prolonged treatment with cephalosporins, immunosuppressed patients at risk for bacteraemia, the presence of prosthetic heart valves and recurrent intra-abdominal infection accompanied by severe sepsis. In patients with prolonged hospital stay and antibacterial therapy, the likelihood of involvement of antibacterial-resistant pathogens must be taken into account. Antimicrobial coverage of Candida spp. is recommended when there is evidence of candidal involvement or in patients with specific risk factors for invasive candidiasis such as immunodeficiency and prolonged antibacterial exposure. In general, antimicrobial therapy should be continued for 5-7 days. If sepsis is still present after 1 week, a diagnostic work up should be performed, and if necessary a surgical reintervention should be considered.

Candida as a risk factor for mortality in peritonitis*

OBJECTIVE

The clinical significance of Candida cultured from peritoneal fluid specimens remains a matter of debate. None of the studies that have addressed this issue have clearly distinguished between community-acquired peritonitis and nosocomial peritonitis. The current study tried to differentiate the pathogenic role of Candida in these two clinical settings and assess its importance on outcome.

DESIGN

A multiple-center, retrospective, case-control study was conducted in intensive care unit patients. The interaction between mortality rates and type of patients was assessed. In the case of a significant interaction, a separate analysis of mortality and morbidity was planned.

SETTING

Seventeen intensive care units in teaching and nonteaching hospitals.

PATIENTS

Cases were patients operated on for peritonitis with Candida cultured from the peritoneal fluid, whereas controls were operated patients free from yeast. Cases and controls were matched for type of infection, Simplified Acute Physiology Score II, age, and time period of hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The following characteristics were collected: demographic variables, underlying disease, severity score, site of infection, microbiological features, and anti-infective treatments. Survival was defined as the main outcome criterion and morbidity variables as secondary criteria. Odds ratios of mortality were calculated. Matching was achieved in 91 cases and 168 controls. Matching criteria, clinical characteristics, and mortality rate were not statistically different between cases and controls. A significant interaction was demonstrated between mortality rates and type of infection, leading to separate analysis of patients with community-acquired peritonitis and nosocomial peritonitis. The subgroup analysis demonstrated an increased mortality rate only in nosocomial peritonitis with fungal isolates (48% vs. 28% in controls, p<.01). Upper gastrointestinal tract site (odds ratio, 4.9; 95% confidence interval, 1.6-14.8) and isolation of Candida species (odds ratio, 3.0; 95% confidence interval, 1.3-6.7, p<.001) were found to be independent risk factors of mortality in nosocomial peritonitis patients.

CONCLUSIONS

Isolation of Candida species appears to be an independent risk factor of mortality in nosocomial peritonitis but not in community-acquired peritonitis.

[Therapeutic management of peritonitis]

Antibiotherapy is a fundamental for the treatment of peritonitis. It may be used before surgery or as a complementary treatment after. Experimental models have demonstrated that infections are both aerobic and anaerobic. During the first stage, septicemic with a high death rate, the infection is due to enterobacteria, mostly Escherichia coli. Between D5 and D7 in surviving animals, there is a second stage with abscesses due to anaerobic bacteria, mostly Bacteroides fragilis. The antibiotic treatment must include these two types of bacteria in its spectrum. The role of Enterococcus faecalis is not clearly defined, but this bacterium must be taken into account in case of organ failure or associated septic shock. Treatment options for secondary peritonitis may be, according to severity, cefoxitin, an Augmentin + gentamycin combination, Tazocillin, or ertapenem. The reference treatment for nosocomial or tertiary peritonitis is the imipenem + amikacin combination. An antifungal treatment (fluconazole) is usually necessary, at least until the results of peritoneal fluid culture are available. The duration of treatment is quite variable, ranging from 48 h in less severe forms to 14 days.