Antibiotic treatment for surgical peritonitis

Primary and secondary peritonitis: an update

Intraabdominal infections are commonly encountered in clinical practice and represent a major cause of morbidity and mortality. The most common etiology is contamination of the peritoneal space by endogenous microflora secondary to loss of integrity of the gastrointestinal tract which results in secondary peritonitis. Primary peritonitis or spontaneous bacterial peritonitis is less common and usually occurs in the presence of ascites without an evident source of infection. Peritonitis associated with chronic ambulatory peritoneal dialysis is not discussed in this review. This review summarizes the significant progress which has been made with regard to primary and secondary peritonitis in the last two decades. The review emphasizes the issues of etiology, pathogenesis, microbiology, diagnosis, medical treatment and prevention.

Is abdominal cavity culture of any value in appendicitis?

BACKGROUND

Intraperitoneal culturing during appendectomy is a routine procedure. Significant decrease in the mortality and dramatic improvement in the morbidity were achieved by using antibiotics perioperatively. The value of intraoperative abdominal cavity culture was assessed in our study.

METHODS

A total of 499 patients formed two groups, those with acute nonperforated appendicitis (group A) and those with perforated appendicitis (group B). Intraoperative abdominal cavity culture were taken randomly in both groups. The perioperative morbidity, the validity, and the impact of positive culture on the antibiotic treatment were examined in both groups.

RESULTS

Clinical diagnosed perforation was confirmed histologically in 176 patients (98.3% accuracy). Intraperitoneal cultures were obtained in 30.1% of the patients in group A and in 67.1% of group B. The majority of the patients in group A were treated preoperatively and postoperatively by a single antibiotic agent whereas 58.0% of the patients in group B were started on triple-agent antibiotics for significantly longer periods (22.4 +/- 9.4 versus 5.7 +/- 7.4 doses, respectively; P < 0.0001). No significant difference was found in both groups in the postoperative complication rate (wound infection, intra-abdominal abscess and small bowel obstruction) whether intra-abdominal culture was obtained or not (5.9% versus 4.7% in group A and 21.2% versus 21.9% in group B; P > 0.05).

CONCLUSION

Traditional intraoperative abdominal cavity culture can be abandoned. In perforated appendicitis, colonic flora can be predicted, and antibiotic therapy should begun without any abdominal cavity culture results. This practical approach will save money and reduce laboratory work without affecting the patient's morbidity.

Early bacterial and inflammatory responses to antibiotic therapy in a model of polymicrobial peritonitis in rats

OBJECTIVE: To assess the consequences of different more or less selective treatments on the microbiological and inflammatory responses within the peritoneum. METHODS: The early effects of various antibiotic regimens were evaluated in a model of polymicrobial peritonitis with specifically prepared organisms. Six regimens (amoxycillin plus gentamicin, pefloxacin, ornidazole, pefloxacin plus ornidazole, imipenem and imipenem plus gentamicin) were evaluated at 24 h and 3 days in a non-fatal model of peritonitis in rats achieved by implantation of a capsule containing Escherichia coli, Bacteroides fragilis and Enterococcus faecalis. RESULTS: Therapies that disregarded several organisms were associated with persistence of the strains and an increased peritoneal inflammatory response within the peritoneum. In contrast, therapies active against Enterobacteriaceae and anaerobes were associated with decreases of all the inoculated organisms and a smaller inflammatory response. CONCLUSION: Therapies that disregarded the microorganisms implicated in peritoneal infection are associated with delayed bacterial eradication. The persistence of these organisms within the peritoneal fluid might be involved in prolonged peritoneal inflammation. Although it disregards enterococci, the standard therapy, represented by therapy against Enterobacteriaceae and anaerobes, demonstrates satisfactory effects towards all the inoculated organisms. This apparent contradiction could be related to mechanisms of bacterial synergy.

Antibiotics for the acute abdomen

Antibiotics are only an adjunct to proper surgical therapy for the treatment of the acute abdomen associated with bacterial secondary peritonitis. Upon presentation, all patients require a preoperative dose of antibiotics for prophylaxis against infection of remaining sterile tissues. Patients found intraoperatively to have an established peritoneal infection benefit from an immediate postoperative course of therapeutic antibiotics. A regimen that adequately covers facultative and aerobic gram-negative bacilli and anaerobic organisms is essential. The duration of therapeutic antibiotics is probably best decided on an individual patient basis. The goal of antibiotics is to reduce the concentration of bacteria invading tissues. The pathogens of bacterial peritonitis are influenced by such factors as the patient's pre-existing chronic diseases, state of acute physiologic debilitation, immunocompetence, recent antibiotic use, recent hospitalization, and neutralization of gastric acidity. Intraoperative peritoneal cultures are most useful in patients suspected of having impaired local host defenses. In these patients, all identified organisms, such as Enterococcus or Candida, may be potential pathogens. The common practice of administering empiric and prolonged courses of broad-spectrum antibiotics in patients who manifest persistent signs of inflammation may be more harmful than beneficial. These patients warrant an exhaustive search for extra-abdominal and intraperitoneal sources of new infection. Otherwise, such use of antibiotics may continue to promote the selection of bacteria that are highly resistant to conventional antibiotics and permit the overgrowth of organisms commonly seen with tertiary peritonitis. The best chance of resolving bacterial peritonitis is through early, aggressive surgical management complemented by short courses of potent antibiotics and appropriate physiologic support. Through these efforts, the clinician tries to help the systemic inflammatory response to benefit the host and not become unregulated, result in MOFS, and produce a high mortality.

Traumatic and nontraumatic perforation of hollow viscera

Hollow viscus injuries are usually managed with few complications. However, if their diagnosis is delayed, or if reparative suture closure should fail, the patient is placed at risk of multiple organ failure. This article presents diagnostic approaches, emphasizing imaging modalities, and therapeutic strategies for three clinical scenarios of hollow viscus perforation: 1) acute appendicitis, 2) gastroduodenal peptic ulcer disease, and 3) trauma.

Antimicrobial therapy for intraabdominal infection

Timely and appropriate antimicrobial therapy is an essential component of the management of intraabdominal infection. Over the past three decades, our ability to treat these infections optimally has been enhanced by an increased understanding of the underlying microbial pathogens, by the development of new antimicrobial agents, and by the completion of several well-controlled clinical trials that guide treatment. This article provides an overview of the approach to antimicrobial therapy in patients with intraabdominal infection. A literature review was performed to collect the information used in this article. Data were derived from experimental and clinical studies evaluating the microbiology and treatment of intraabdominal infections. Evidence from both animal studies and clinical trials supports the initiation of empiric antimicrobial therapy directed against Escherichia coli and other common members of the family Enterobacteriaceae, as well as the anaerobe Bacteroides fragilis. Based on this premise, the clinician is faced with a broad selection of possible single agents, as well as combinations of agents that fulfill these criteria. The factors involved in selecting a specific regimen include consideration of the antimicrobial spectrum of various agents, experimental animal studies evaluating their efficacy, and, importantly, efficacy in well-designed clinical trials. In addition, consideration of safety profiles, pharmacokinetics, and cost of specific pharmaceutical agents should be made when selecting a regimen. Antimicrobial therapy is an important component of the management of intraabdominal infection. The results of well-designed clinical trials evaluating various aspects of therapy should serve to guide treatment.

Efficacy of blood cultures in the critically ill surgical patient

BACKGROUND

Blood cultures are commonly obtained to delineate an infectious process in the ill surgical patient with fever, leukocytosis, or other septic parameters. We studied how often bacteremia was diagnosed, whether a positive blood culture changed therapy, and the cost analysis of this practice.

METHODS

A heterogenous adult population of 158 patients at high risk for bacteremia was retrospectively reviewed. Blood cultures were not obtained in 37 patients, and thus they were excluded from further study.

RESULTS

We obtained 1040 blood cultures in 121 patients. Forty-eight patients (40%) had 122 positive cultures; 20 of these patients had only false-positive cultures. Thus 28 patients (23%) had 82 cultures that represented true bacteremia. Among clinical events, only antibiotic changes and interventions occurred significantly more often as a result of a positive blood culture (p < or = 0.05). No change in therapy occurred in most patients with both positive and negative cultures. Cost for all cultures was $60,058 or $1,251 per positive culture and $1,877 per clinical therapeutic event change.

CONCLUSIONS

Routine ordering of blood cultures is not cost-effective, rarely alters or provides therapeutic direction, and appears not to affect mortality. Obtaining clinically indicated blood cultures as a secondary rather than a primary diagnostic measure is suggested.

Efficacy of metronidazole lavage in treatment of intraperitoneal sepsis. A prospective study

In a prospective study, 182 consecutive patients were included for the treatment of intraabdominal sepsis with adjuvant metronidazole lavage that was carried out at the end of the operative procedures. Eighty of them underwent emergency surgery for peritonitis and 102 elective surgery for a variety of lesions. Although fecal peritonitis was found in 23 and malignant tumors in 84 patients, there was not a single instance of intraabdominal abscess in 182 patients, but the incidence of wound infection was 2.66% in the emergency group and 0% in the elective group; mortality was 5% and 3.9%, respectively. Therefore, adjuvant metronidazole lavage provides confidence in the treatment of intraperitoneal abscess, and it enhances a quick recovery. It is safe to use and cost effective.

Management of secondary peritonitis

OBJECTIVE

The authors review current definition, classification, scoring, microbiology, inflammatory response, and goals of management of secondary peritonitis.

SUMMARY BACKGROUND DATA

Despite improved diagnostic modalities, potent antibiotics, modern intensive care, and aggressive surgical treatment, up to one third of patients still die of severe secondary peritonitis. Against the background of current understanding of the local and systemic inflammatory response associated with peritonitis, there is growing controversy concerning the optimal antibiotic and operative therapy, intensified by lack of properly conducted randomized studies. In this overview the authors attempt to outline controversies, suggest a practical clinical approach, and highlight issues necessitating further research.

METHODS

The authors review the literature and report their experience.

RESULTS

The emerging concepts concerning antibiotic treatment suggest that less-in terms of the number of drugs and the duration of treatment-is better. The classical single operation for peritonitis, which obliterates the source of infection and purges the peritoneal cavity, may be inadequate for severe forms of peritonitis; for the latter, more aggressive surgical techniques are necessary to decompress increased intra-abdominal pressure and prevent or treat persistent and recurrent infection. The widespread acceptance of the more aggressive and demanding surgical methods has been hampered by the lack of randomized trials and reportedly high associated morbidity rates.

CONCLUSIONS

Sepsis represents the host's systemic inflammatory response to bacterial peritonitis. To improve results, both the initiator and the biologic consequences of the peritoneal infective-inflammatory process should be addressed. The initiator may be better controlled in severe forms of peritonitis by aggressive surgical methods, whereas the search for methods to abort its systemic consequences is continuing.

A comparison of imipenem/cilastatin with the combination of cefuroxime and metronidazole in the treatment of intra-abdominal infections

515 patients with intra-abdominal infection participated in an open randomized comparative multicenter trial in order to compare the efficacy, safety, and tolerance of imipenem/cilastatin with cefuroxime/metronidazole. 258 patients (mean age 56 years) received imipenem/cilastatin 1.5-2.0 g/day, and 257 patients (mean age 54 years) received cefuroxime 3.0-4.5 g/day plus metronidazole 1.0-1.5 g/day for at least 3 days. 130/161 evaluable patients (80.8%) receiving imipenem/cilastatin and 124/145 evaluable patients (85.5%) receiving cefuroxime/metronidazole were clinically cured. The microbiological response was favorable in 86.9% in the imipenem/cilastatin group and in 90.8% in the cefuroxime/metronidazole group. The two treatment groups were similar with respect to median time to defervescence which was 4 days. The median duration of treatment was 6 days and the median time to discharge from hospital was 9 days in both groups. Drug-related adverse reactions were observed in 14 patients receiving iminpenem/cilastatin and in 8 patients receiving cefuroxime/metronidazole. 19 patients in the imipenen/cilastatin group and 12 patients in the cefuroxime/metronidazole group died. No correlation was found between the deaths and the study drugs. The present study shows that intra-abdominal infections can be treated successfully with imipenem/cilastatin as well as with cefuroxime/metronidazole.

Pharmacoeconomics of appropriate antimicrobial use

Pharmacoeconomics is founded on the key principle of economics, which is that society's resources are limited, and therefore, choices have to be made about the use of those resources. Pharmacoeconomic analysis should estimate the costs and consequences of different drug treatments, including the use of all health care resources, not drug costs alone. Application of these principles to appropriate antimicrobial treatment requires separate consideration of a sequence of questions: Who needs treatment? What are the best drug, dose, route of administration, and duration of therapy? What information do we have about the outcomes of treatment? None of these questions is easy to answer, but economic analysis will help the decision maker by making explicit the costs and consequences of the available alternatives.

Once-daily aminoglycoside administration in gram-negative sepsis. Economic and practical aspects

A fuller understanding of the pharmacodynamics of aminoglycoside antibiotics now exists compared with when they were introduced. Recent findings have shown that once-daily dosage regimens of aminoglycosides are as effective as bd or tid regimens in the treatment of Gram-negative sepsis. However, radical changes in dosage frequency based on this knowledge are resisted by some physicians because of fears about the peak concentration toxicity of aminoglycosides. These fears have been shown to be misplaced. The delay in the translation of research findings into practice may be attributable to the sheer quantity of medical literature and the limited time that clinicians have available to read it. Because healthcare resources are finite, physicians are increasingly becoming aware of the need to use drug therapy in the most cost-effective way. An important component of aminoglycoside therapy that may persuade clinicians to change their practice is the organised consideration of the various costs associated with different administration regimens. This review examines the source of those costs, and endorses once-daily dosage of aminoglycosides from both an economic and practical viewpoint.

Pharmacological management of pain and infection in the surgical oncology patient

Surgical oncology patients are often high-risk patients that require careful perioperative management for a successful outcome. Prophylactic antibiotics are needed to prevent infection in tissues compromised by disease, radiation, or chemotherapy. Pain control is needed to prevent the stress response to surgery from worsening the outcome and to aid in the maintenance of patient comfort.

Minimal antibiotic therapy after emergency abdominal surgery: a prospective study

The optimal duration for courses of antibiotic therapy following emergency abdominal surgery was examined. The length of postoperative administration was based on the operative findings of contamination versus infection and the degree of the latter. A total of 163 patients (mean APACHE II score 7) were stratified into four groups: group 1 (60 patients), no postoperative antibiotics; group 2 (32), antibiotic therapy for 24 h; group 3 (48), administration for 48 h; and group 4 (23), antibiotic therapy for 72 h to 5 days. Three patients (2 per cent) died. Wound infection developed in 12 patients (7 per cent) and postoperative intra-abdominal infection in two (1 per cent). Antibiotics were stopped according to the protocol in 28 patients in spite of continued fever; one developed a subhepatic abscess and three had wound infections. Distinguishing contamination from infection and operative stratification of the latter allowed a successful 'minimal' postoperative antibiotic policy to be employed.

Peritoneal cultures and antibiotic therapy in pediatric perforated appendicitis

We retrospectively reviewed 70 cases of perforated appendicitis in children to examine the relationship between postoperative antibiotic selection and culture results from the peritoneal cavity. Initial antibiotic therapy chosen for the children consisted of a three-drug combination in 54 (77%) patients. Peritoneal cultures were performed in 58 (83%) patients. Escherichia coli and Bacteriodes fragilis were the most common bacterial isolates from the peritoneal culture. Only 7 (10%) patients had their antibiotic regimen changed after the culture results were available, of which 2 changes brought drug therapy into compliance with the cultures and 5 changes were inappropriate with respect to the peritoneal cultures. Of the remaining 51 patients with culture data available, 39 should have had changes to bring the antibiotic therapy into compliance with the observed culture results. These data indicate that surgeons select antibiotic therapy for perforated appendicitis in children based on assumptions of which organisms should be present in the infection and not on culture data. There appears to be no clinical usefulness to the routine culturing of the peritoneal cavity in children with perforated appendicitis.

Pharmacoeconomics of antibacterial treatment

Antibacterial drugs account for between 3 and 25% of all prescriptions, between 6 and 21% of the total market value of drugs in a single country, and up to 50% of the drug budget in hospitals. Bacterial infection is widely perceived as disease caused by harmful outside agents which can be isolated and tested to select the best drug for treatment. In fact, the need for any treatment and the pros and cons of different drugs are just as debatable as in any other therapeutic area. Moreover, the bacteria which make up the normal flora of the body fulfil important roles, so that the ecological implications of treatment for the individual and for society should be considered in assessing the costs and consequences of antibacterial treatment. In this review we outline the most important issues relating to the treatment of bacterial infection in the community and in the hospital, contrasting information from developed and developing countries where appropriate. We review the existing literature on economic evaluation, but in general most of the literature deals with containing the costs of antibacterial drugs in hospitals, and there are many gaps in the literature on cost-effectiveness of treatment. Consequently there are still extreme variations in medical practice which present a challenge for future evaluation. As the outcomes of antibacterial treatment are apparent in a few weeks or months, this is an ideal field for testing pharmacoeconomic methodology. The desire to overcome medical practice variation through consensus statements should be avoided. Instead we recommend wider application of decision analysis to acknowledge that choices exist for the diagnosis and treatment of bacterial infection and to gather information about the implications of these choices. Much of the existing literature would be improved by a more explicit definition of costs. Direct costs to the health services should be distinguished from non medical costs. Moreover, the analysis should consider whether savings from one budget result in costs to another health service budget, or to the patient (transfer costs). These deficiencies in cost analysis will be relatively easy to correct. Of more concern is the fact that the efficacy of much antibacterial treatment is either totally debatable, or variable, depending on factors such as the type of patient treated or the quality of delivery of treatment.(ABSTRACT TRUNCATED AT 400 WORDS)