Evaluation of antibiotic therapy following penetrating abdominal trauma

Antibiotic prophylaxis in trauma: Global Alliance for Infection in Surgery, Surgical Infection Society Europe, World Surgical Infection Society, American Association for the Surgery of Trauma, and World Society of Emergency Surgery guidelines

Trauma is a complex disease, and the use of antibiotic prophylaxis (AP) in trauma patients is common practice. However, considering the increasing rates of antibiotic resistance, AP use should be questioned and limited only to specific cases. Antibiotic stewardship is of paramount importance in fighting resistance spread. Definitive rules or precise indications about AP in trauma remain unclear. The present article describes the indications of AP in traumatic lesions to the head, brain, torso, maxillofacial, extremities, skin, and soft tissues endorsed by the Global Alliance for Infection in Surgery, Surgical Infection Society Europe, World Surgical Infection Society, American Association for the Surgery of Trauma, and World Society of Emergency Surgery.

Current status of initial antibiotic therapy and analysis of infections in patients with solitary abdominal trauma: a multicenter trial in Korea

Purpose

Proper use of antibiotics during emergency abdominal surgery is essential in reducing the incidence of surgical site infection. However, no studies have investigated the type of antibiotics and duration of therapy in individuals with abdominal trauma in Korea. We aimed to investigate the status of initial antibiotic therapy in patients with solitary abdominal trauma.

Methods

From January 2015 to December 2015, we retrospectively analyzed the medical records of patients with solitary abdominal trauma from 17 institutions including regional trauma centers in South Korea. Both blunt and penetrating abdominal injuries were included. Time from arrival to initial antibiotic therapy, rate of antibiotic use upon injury mechanism, injured organ, type, and duration of antibiotic use, and postoperative infection were investigated.

Results

Data of the 311 patients were collected. The use of antibiotic was initiated in 96.4% of patients with penetrating injury and 79.7% with blunt injury. Initial antibiotics therapy was provided to 78.2% of patients with solid organ injury and 97.5% with hollow viscus injury. The mean day of using antibiotics was 6 days in solid organ injuries, 6.2 days in hollow viscus. Infection within 2 weeks of admission occurred in 36 cases. Infection was related to injury severity (Abbreviated Injury Scale of >3), hollow viscus injury, operation, open abdomen, colon perforation, and RBC transfusion. There was no infection in cases with laparoscopic operation. Duration of antibiotics did not affect the infection rate.

Conclusion

Antibiotics are used extensively (84.2%) and for long duration (6.2 days) in patients with abdominal injury in Korea.

Prophylactic antibiotics for penetrating abdominal trauma: duration of use and antibiotic choice

BACKGROUND

Penetrating abdominal trauma (PAT) is a common type of trauma leading to admission to hospital, which often progresses to septic complications. Antibiotics are commonly administered as prophylaxis prior to laparotomy for PAT. However, an earlier Cochrane Review intending to compare antibiotics with placebo identified no relevant randomised controlled trials (RCTs). Despite this, many RCTs have been carried out that compare different agents and durations of antibiotic therapy. To date, no systematic review of these trials has been performed.

OBJECTIVES

To assess the effects of antibiotics in penetrating abdominal trauma, with respect to the type of agent administered and the duration of therapy.

SEARCH METHODS

We searched the following electronic databases for relevant randomised controlled trials, from database inception to 23 July 2019; Cochrane Injuries Group's Specialised Register, CENTRAL, MEDLINE Ovid, MEDLINE Ovid In-Process & Other Non-Indexed Citations, MEDLINE Ovid Daily and Ovid OLDMEDLINE, Embase Classic + Embase Ovid, ISI Web of Science (SCI-EXPANDED, SSCI, CPCI-S & CPSI-SSH), and two clinical trials registers. We also searched reference lists from included studies. We applied no restrictions on language or date of publication.

SELECTION CRITERIA

We included RCTs only. We included studies involving participants of all ages, which were conducted in secondary care hospitals only. We included studies of participants who had an isolated penetrating abdominal wound that breached the peritoneum, who were not already taking antibiotics.

DATA COLLECTION AND ANALYSIS

Two study authors independently extracted data and assessed risk of bias. We used standard Cochrane methods. We aggregated study results using a random-effects model. We also conducted trial sequential analysis (TSA) to help reduce type I and II errors in our analyses.

MAIN RESULTS

We included 29 RCTs, involving a total of 4458 participants. We deemed 23 trials to be at high risk of bias in at least one domain. We are uncertain of the effect of a long course of antibiotic prophylaxis (> 24 hours) compared to a short course (≤ 24 hours) on abdominal surgical site infection (RR 1.00, 95% CI 0.81 to 1.23; I² = 0%; 7 studies, 1261 participants; very low-quality evidence), mortality (Peto OR 1.67, 95% CI 0.73 to 3.82; I² = 8%; 7 studies, 1261 participants; very low-quality evidence), or intra-abdominal infection (RR 1.23, 95% CI 0.84 to 1.80; I² = 0%; 6 studies, 111 participants; very-low quality evidence). Based on very low-quality evidence from fifteen studies, involving 2020 participants, which compared different drug regimens with activity against three classes of gastrointestinal flora (gram positive, gram negative, anaerobic), we are uncertain whether there is a benefit of one regimen over another. TSA showed the majority of comparisons did not cross the alpha adjusted boundary for benefit or harm, or reached the required information size, indicating that further studies are required for these analyses. However, in the three analyses which crossed the boundary for futility, further studies are unlikely to show benefit or harm.

AUTHORS' CONCLUSIONS

Very low-quality evidence means that we are uncertain about the effect of either the duration of antibiotic prophylaxis, or the superiority of one drug regimen over another for penetrating abdominal trauma on abdominal surgical site infection rates, mortality, or intra-abdominal infections. Future RCTs should be adequately powered, test currently used antibiotics, known to be effective against gut flora, use methodology to minimise the risk of bias, and adequately report the level of peritoneal contamination encountered at laparotomy.

Prophylactic antibiotic use in penetrating abdominal trauma: an Eastern Association for the Surgery of Trauma practice management guideline

BACKGROUND

The use of prophylactic antibiotics in penetrating abdominal trauma has resulted in decreased infection rates. The Eastern Association for the Surgery of Trauma (EAST) first published its practice management guidelines (PMGs) for the use of prophylactic antibiotics in penetrating abdominal trauma in 1998. During the next decade, several new prospective studies were published on this topic. In addition, the practice of damage control laparotomy became widely used, and additional questions arose as to the role of prophylactic antibiotics in this setting. Thus, the EAST Practice Management Guidelines Committee set out to update the original PMG.

METHODS

A search of the National Library of Medicine and the National Institutes of Health MEDLINE databases was performed using PubMed (www.pubmed.gov) and specific key words. The search retrieved English language articles regarding the use of antibiotics in penetrating abdominal trauma published from 1973 to 2011. The topics investigated were the need for perioperative antibiotics, the duration of antibiotic therapy, the dose of antibiotics in patients presenting in hemorrhagic shock, and the appropriate duration of antibiotic therapy in the setting of damage control laparotomy.

RESULTS

Forty-four articles were identified for inclusion in this review.

CONCLUSION

There is evidence to support a Level I recommendation that prophylactic antibiotics should only be administered for 24 hours in the presence of a hollow viscus injury. In addition, there are no data to support continuing prophylactic antibiotics longer than 24 hours in damage control laparotomy.

"SCIP"ping antibiotic prophylaxis guidelines in trauma: The consequences of noncompliance

OBJECTIVE

The Surgical Care Improvement Project (SCIP) established surgical antibiotic prophylaxis guidelines as part of a national patient safety initiative aimed at reducing surgical complications such as surgical site infection (SSI). Although these antibiotic prophylaxis guidelines have become well established in surgical patients, they remain largely unstudied in patients with injury from trauma undergoing operative procedures. We sought to determine the role of these antibiotic prophylaxis guidelines in preventing SSI in patients undergoing trauma laparotomy.

METHODS

A retrospective review of all patients who underwent emergency trauma laparotomy at two Level I trauma centers (2007-2008) revealed 306 patients who survived more than 4 days after injury. Demographics and clinical risk SSI factors were analyzed, and patients were compared on the basis of adherence to the following SCIP guidelines: (1) prophylactic antibiotic given, (2) antibiotic received within 1 hour before incision, (3) correct antibiotic selection, and (4) discontinuation of antibiotic within 24 hours after surgery. The primary study end point was the development of SSI.

RESULTS

The study sample varied by age (mean [SD], 32 [16] years) and injury mechanism (gunshot wound 44%, stab wound 27%, blunt trauma 30%). When patients with perioperative antibiotic management complying with the four SCIP antibiotic guidelines (n = 151) were compared with those who did not comply (n = 155), no difference between age, shock, small bowel or colon resection, damage control procedures, and skin closure was detected (p > 0.05). After controlling for injury severity score, hypotension, blood transfusion, enteric injury, operative duration, and other potential confounding variables in a multivariate analysis, complete adherence to these four SCIP antibiotic guidelines independently decreased the risk of SSI (odds ratio, 0.43; 95% confidence interval, 0.20-0.94; p = 0.035). Patients adhering to these guidelines less often developed SSI (17% vs. 33%, p = 0.001) and had shorter overall hospital duration of antibiotics (4 [6] vs. 9 [11] days, p < 0.001) and hospital length of stay (14 [13] vs. 19 [23] days, p = 0.016), although no difference in mortality was detected (p > 0.05).

CONCLUSIONS

Our results suggest that SCIP antibiotic prophylaxis guidelines effectively reduce the risk of SSI in patients undergoing trauma laparotomy. Despite the emergent nature of operative procedures for trauma, efforts to adhere to these antibiotic guidelines should be maintained.

Prevention of infections associated with combat-related thoracic and abdominal cavity injuries

Trauma-associated injuries of the thorax and abdomen account for the majority of combat trauma-associated deaths, and infectious complications are common in those who survive the initial injury. This review focuses on the initial surgical and medical management of torso injuries intended to diminish the occurrence of infection. The evidence for recommendations is drawn from published military and civilian data in case reports, clinical trials, meta-analyses, and previously published guidelines, in the interval since publication of the 2008 guidelines. The emphasis of these recommendations is on actions that can be taken in the forward-deployed setting within hours to days of injury. This evidence-based medicine review was produced to support the Guidelines for the Prevention of Infections Associated With Combat-Related Injuries: 2011 Update contained in this supplement of Journal of Trauma.

Basic aspects of and general problems in surgical infections

Antibiotics are important in the prophylaxis and treatment of surgical infections as well as in the management of nosocomial infections acquired postoperatively in surgical patients. Surgeons encounter a range of infectious conditions, including established single-pathogen infections of soft tissues, polymicrobial intra-abdominal infections, and resistant gram-negative nosocomial infections such as ventilator-associated and aspiration pneumonia. Preoperative antibiotic administration has been shown to reduce the risk of surgical site infections and is now an accepted part of the standard care for most surgical patients. In patients with established single-pathogen or polymicrobial infections requiring surgery, studies have shown appropriate empiric antibiotic therapy to be an important adjunct to surgical intervention and general supportive measures in improving patient outcome. Antibiotics are also essential for those who develop postoperative nosocomial infections. Empiric coverage of the most likely causative organisms, especially in synergistic polymicrobial mixed infections, is one of the keys to successful prophylaxis and treatment of surgical infections.

The role of beta-lactam/beta-lactamase inhibitor combinations in surgical infections

Many surgical infections are characterized by synergistic polymicrobial mixed infection, for which broad-spectrum antimicrobial therapy is usually administered on an empiric basis. Until relatively recently, standard empiric therapeutic regimens have involved the use of two or more antibiotics, such as aminoglycosides and anti-anaerobic agents, to achieve adequate aerobic and anaerobic coverage. There are often substantial drawbacks, however, such as drug-induced toxicity and high costs of treatment. Evidence from a number of clinical studies suggests that single-agent therapy with beta-lactam/beta-lactamase inhibitor combinations is a suitable and cost-effective alternative to multidrug regimens, as well as to monotherapy with cephalosporins or carbapenems in the treatment of intra-abdominal, gynecologic, and diabetic foot infections, and brain abscesses. These agents are also suitable for use in perioperative prophylaxis and may offer benefits over other agents in terms of reduced incidence of surgical wound infections and lower costs.

Current management of colon trauma

This article offers a comprehensive review of colon trauma from World War I to the present. The process of evidence-based medicine was used to analyze the data from the past 25 years and define standards of care in the field. Where data are less compelling, recommendations and suggestions are provided for future research. Topics highlighted include destructive and nondestructive colon injuries, rectal injuries, on-table colonic lavage, colonic bypass tubes, risk factors, perioperative antibiotics, and colostomy closure.

Microbiology and management of intra-abdominal infections in children

The present review describes the microbiology, diagnosis, and management of intra-abdominal infections in children. Infection generally occurs due to the entry of enteric micro-organisms into the peritoneal cavity through a defect in the wall of the intestine or other viscus as a result of obstruction, infarction, or direct trauma. Mixed aerobic and anaerobic flora can be recovered from the peritoneal cavity of these patients. The predominant aerobic isolates are Escherichia coli, and enterococci; the main anaerobic bacteria are Bacteroides fragilis group, Peptostreptococcus spp. and Clostridium spp. The treatment of abdominal infection includes surgical correction and drainage, and administration of antimicrobials that are effective against both aerobic and anaerobic micro-organisms.

Infection in Penetrating Abdominal Trauma: Risk Factors and Preventive Antibiotics

Infection remains the greatest risk for victims of penetrating abdominal injury with major infections occurring in 10 to 15 per cent. Attributable mortality is approximately 30 per cent of those who develop major abdominal infections. In addition to this morbidity infection adds approximately $43,000.00 of hospital charges per infected patients. This article addresses two significant areas: risk factors and antibiotic utilization. The most important risk factor is the presence of hollow viscus injury; colonic wounding carries the highest incidence of infection relative to intra-abdominal organs injured. Pancreatic and liver injuries significantly increase infection risk when combined with hollow viscus wounds. The degree of injury as measured by the volume of hemorrhage and the presence of shock as well as the anatomic degree of injury likewise correlates with the incidence of septic morbidity. Antibiotic utilization is addressed by the three issues of antibiotic agents of choice, duration of administration, and optimal dosing. Regimens of choice should include anaerobic coverage. Twenty-four hours of antibiotic administration is satisfactory with currently available agents. Evidence-based medicine analyses from the Eastern Association for the Surgery of Trauma have addressed those two issues. There are few data on optimal dosing. Increased volumes of distribution and rates of excretion have been demonstrated in trauma patients. This would suggest that higher-than-normal doses should be used. Laboratory studies would support such an approach. However, significant clinical research is desirable to address issues of concentration-dependent bacterial killing and time-dependent killing. Those pharmo-dynamic considerations are variable among antibiotic classes.

Co-amoxiclav pharmacokinetics during posttraumatic hemorrhagic shock

OBJECTIVE

To determine the effects of severe trauma with hemorrhagic shock on amoxicillin and clavulanate concentrations in plasma and their pharmacokinetics.

DESIGN

A prospective, open, descriptive study.

SETTING

A 12-bed, adult surgical intensive care unit in a university-affiliated hospital in France.

SUBJECTS

Subjects were 12 patients (10 men, 2 women) with severe trauma: median (range) Injury Severity Score, 38 (17-48); Acute Physiology and Chronic Health Evaluation II, 16 (7-38); Simplified Acute Physiology Score II, 41 (23-77). Also enrolled were 12 healthy volunteers who were matched on age (+/-5 yrs), gender, and body-surface area (+/-20 cm2). All the trauma patients suffered hemorrhagic shock defined as the association of at least one episode of systolic blood pressure <90 mm Hg and an intravascular volume expansion >2000 mL between trauma and surgery.

INTERVENTION

Prophylactic perioperative administration of 2 g of amoxicillin and 0.2 g of clavulanate in combination during the first 12 hrs posttrauma in patients, and at the start of the pharmacokinetic study in volunteers.

MEASUREMENTS AND MAIN RESULTS

Serial plasma samples (n = 13) were obtained after the first antibiotic administration to measure antibiotic levels by using high-performance liquid chromatography assays. Compared with volunteers, trauma patients had higher plasma amoxicillin and clavulanate concentrations, attributed to a reduction of the volume of distribution (p =.001 and p =.06, respectively) and, to a lesser extent, of the total body clearance (p =.09 and p =.20, respectively). Consequently, amoxicillin and clavulanate elimination half-lives were similar for the two groups of subjects. The interindividual variabilities for all the amoxicillin pharmacokinetic parameters were higher in patients.

CONCLUSIONS

In trauma patients with hemorrhagic shock requiring surgery, the administration of 2 g of amoxicillin and 0.2 g of clavulanate seems adequate, according to the antibiotic concentrations observed in plasma for both drugs. However, further studies exploring antibiotic concentrations in tissues are warranted.

Perioperative antibiotic use in high-risk penetrating hollow viscus injury: a prospective randomized, double-blind, placebo-control trial of 24 hours versus 5 days

BACKGROUND

The purpose of this study was to compare the safety and therapeutic efficacy of a 24-hour versus 5-day course of ampicillin/sulbactam for the prevention of postoperative infections in high-risk patients sustaining hollow viscus injury from penetrating abdominal trauma.

METHODS

A total of 317 patients from four Level I trauma centers with penetrating abdominal injuries and at least one hollow viscus perforation each received one preoperative and three postoperative doses of ampicillin/sulbactam 3 g intravenously. After receiving 24 hours of unblinded ampicillin/sulbactam, patients were then randomized into one of two groups. Group 1 received 4 additional days of blinded ampicillin/sulbactam (5 days total of antibiotic), and Group 2 received 4 days of placebo (24 hours of antibiotic). Patients were assessed postoperatively for occurrence of deep surgical-site infections (intra-abdominal abscess, fasciitis, and peritonitis) and superficial (wound) surgical-site infections. Development of nonsurgical-site infections (e.g., pneumonia, urinary tract infection, phlebitis, and cellulitis) was also recorded. Continuous variables were analyzed by analysis of variance and discrete variables by the Cochran-Mantel-Haenszel chi2 test. Multivariate logistic regression analyses were also performed to identify independent risk factors for postoperative infection.

RESULTS

A total of 159 patients were randomized into Group 1, and 158 patients were randomized into Group 2. The Injury Severity Score and penetrating abdominal trauma index were 18+/-8 and 21+/-13, respectively, for Group 1 and 18+/-9 and 20+/-15, respectively, for Group 2. A total of 162 (51%) patients sustained one or more colon injuries (82 in Group 1 and 80 in Group 2). There were 16 (10%) surgical-site infections in Group 1 and 13 (8%) surgical-site infections in Group 2 (p = 0.74). Group 1 patients experienced 17 (11%) nonsurgical-site infections, whereas Group 2 had 32 (20%) nonsurgical-site infections. This difference, however, was not statistically significant (p = 0.16). Only the total number of blood units transfused and the presence of a PATI score greater than or equal to 25 were found to be independently associated with the development of a postoperative surgical- and nonsurgical-site infections (p = 0.001 and p = 0.003, respectively). Of note, the presence of a colon injury was not found to be an independent risk factor (p = 0.11) for either surgical or nonsurgical site postoperative infection in our study.

CONCLUSION

High-risk patients with colon or other hollow viscus injuries from penetrating abdominal trauma are at no greater risk for surgical-site or nonsurgical-site infection when treated with only a 24-hour course of a broad-spectrum antibiotic.

Factors affecting mortality and morbidity in patients with abdominal gunshot wounds

Risk factors that may independently predict mortality and morbidity in patients with abdominal gunshot wounds have not been fully elucidated. We prospectively studied the effects of 12 potential risk factors on mortality and morbidity in 82 patients with abdominal gunshot wounds who required laparotomy. Univariate analysis of these factors revealed that shock on admission, presence of penetrating colon injury and number of intra-abdominal organs injured (NOI)>2 were associated with greater than threefold increased incidence of death (p<0.05). Penetrating abdominal trauma index (PATI) score>15 was associated with twentyfold increased incidence of death (P<0.0001). Multivariate analysis showed that only PATI (P=0.001), number of postoperative complications per patient (N(comp)) (P=0.023) and presence of shock on admission (P=0. 028) were independently significant in predicting mortality. PATI was the only risk factor that independently predicted the development of postoperative infectious complications and N(comp) (P<0.0001). The type of gun used was not a significant risk factor (P>0.05). The 15 (18.3%) non-survivors were significantly older than survivors (P=0.02), had longer operations (P=0.004) and their NOI, PATI and N(comp) were significantly higher (P<0.001). The uniformly prolonged injury to surgery time in all patients contributed to the high incidence of infectious complications (62.2%) and mortality. PATI score was the most important factor found to be independently associated with mortality and morbidity in our subset of patients with prolonged injury to surgery time and high rate of colon injury.

The duration of antibiotic administration in penetrating abdominal trauma

BACKGROUND

The epidemiology of penetrating abdominal trauma is changing to reflect an increasing incidence of multiple injuries. Not only do multiple injuries increase the risk of infection, a very high risk of serious infection is conferred by immunosuppression from hemorrhage and transfusion and the high likelihood of intestinal injury, especially to the colon. Optimal timing and choice of presumptive antibiotic therapy has been established for penetrating trauma, but duration has not been studied extensively in such seriously injured patients. The purpose of this study was to test the hypothesis that 24 hours of antibiotic therapy remains sufficient to reduce the incidence of infection in penetrating abdominal trauma.

METHODS

Three hundred fourteen consecutive patients with penetrating abdominal trauma were prospectively randomized into two groups: Group I received 24 hours of intravenous cefoxitin (1 g q6h) and group II received 5 days of intravenous cefoxitin. The development of a deep surgical site (intra-abdominal) infection as well as any type of nosocomial infection, as defined by the Centers for Disease Control and Prevention, (ie, surgical site infections, catheter-related infections, urinary tract, pneumonia), was recorded. Hospital length of stay was a secondary endpoint. Statistical analysis included chi-square tests for coordinate variables and two-tailed unpaired t tests for continuous variables. The independence of risk factors for the development of infection was assessed by multivariate analysis of variance. Significance was determined when P <0.05.

RESULTS

Three hundred patients were evaluable. There was no postoperative mortality, and no differences in overall length of hospitalization between groups. The duration of antibiotic treatment had no influence on the development of any infection (P = 0.136) or an intraabdominal infection (P = 0.336). Only colon injury was an independent predictor of the development of an intraabdominal infection (P = 0.0031). However, the overall infection incidence was affected by preoperative shock (P = 0.003), colon (P = 0.0004), central nervous system (CNS) injuries (P = 0.031), and the number of injured organs (P = 0.026). Several factors, including intraoperative shock (P = 0.021) and injuries to the colon (P = 0.0008), CNS (P = 0.0001), and chest (P = 0.0006), were independent contributors to prolongation of the hospital stay.

CONCLUSIONS

Twenty-four hours of presumptive intravenous cefoxitin versus 5 days of therapy made no difference in the prevention of postoperative infection or length of hospitalization. Infection was associated with shock on admission to the emergency department, the number of intra-abdominal organs injured, colon injury specifically, and injury to the central nervous system. Intra-abdominal infection was predicted only by colon injury. Prolonged hospitalization was associated with intraoperative shock and injuries to the chest, colon, or central nervous system.

Piperacillin/tazobactam in the treatment of polymicrobial infections

Polymicrobial infections are characterized by the presence of micro-organisms from more than one group of bacteria. Empirical treatment of polymicrobial infections requires an agent active against both anaerobic and aerobic/facultative bacteria. An aminoglycoside used in combination with an anti-anaerobe agent is commonly used to treat polymicrobial infections. However, aminoglycoside nephrotoxicity and treatment failures raise questions about the use of such regimens. Among non-aminoglycoside treatment regimens such as penicillin and cephalosporins, effectiveness has been compromised by bacteria producing extended spectrum beta-lactamases. Cefoxitin shows satisfactory results for treatment of intra-abdominal infections. Other studies have shown good results with imipenem, cefotetan and piperacillin used as single agents. Piperacillin/tazobactam, a new combination broad-spectrum antibiotic and potent beta-lactamase inhibitor, can be used for the treatment of infections caused by piperacillin-sensitive micro-organisms as well as beta-lactamase-producing, piperacillin-resistant organisms. This broad-spectrum activity is appropriate for infections traditionally treated empirically by double or triple antibiotic therapy.

Intra-abdominal infections in children. Pathogenesis, diagnosis and management

Intra-abdominal infections in children that follow perforation of viscus often involve the gastrointestinal aerobic and anaerobic bacterial flora. These organisms possess various virulence factors and exhibit potential synergy. The intra-abdominal infection is biphasic, with the Enterobacteriaceae as the major pathogens in the peritonitis stage, and the Bacteroides fragilis group predominating in the abscess stage. Experiments with animals and experience in patients support the need to use single or combined antimicrobial agent therapy that is effective against both Enterobacteriaceae and the B. fragilis group.

Empiric antibiotic therapy of abdominal sepsis and serious perioperative infections

This article discusses empiric therapy for several serious infections in surgical patients. The accepted antibiotic treatment for purulent peritonitis, the empiric treatment of postsurgical wound infection, and the empiric treatment of postsurgical pneumonia are discussed. The cost of the various regimens is listed. Recommendation of the various regimens is based on the seriousness of the infection, peculiarities of the hospital flora, effectiveness of the regimens, and cost.

Risk factors for infection in the trauma patient

The most common cause of late death following trauma is sepsis. The traumatized patient has a significant increased risk of infection. Transfusion, hypotension, and prolonged ventilatory support are predictive of septic complications. In addition, the trauma patient has a higher predisposition to pneumonia than nontrauma patients (18% versus 3% incidence of pneumonia, P < .001). Additional risk factors include the degree of nutrition status and the type of medications used during surgery. Immunologic depression may be an additional risk factor. There is mounting evidence that trauma can result in host defense abnormalities. To prevent the significant mortality caused by sepsis, close surveillance must be maintained, nutritional status must be optimal, and liberal use of antibiotics should be discouraged. Their use should be guided by appropriate cultures and sensitivities.

Short-course antibiotic prophylaxis in penetrating abdominal injuries: ceftriaxone versus cefoxitin

This was a prospective, randomized study of 123 patients with penetrating abdominal injuries. The patients received ceftriaxone or cefoxitin for 24 h (in the presence of colonic injury, 48 h). The overall incidence of abdominal sepsis was 7.3 per cent (ceftriaxone 5 per cent, cefoxitin 9.5 per cent, P greater than 0.05). Colonic injury was the most important risk factor for the development of septic complications. Other factors, such as the weapon used, a prehospital time longer than 4 h, shock on admission, multiple organ injuries, and small bowel perforation, did not influence the incidence of sepsis.

Cefoxitin in the prevention and treatment of infections

A review of the literature indicates that cefoxitin is an effective single-agent therapy for community-acquired intra-abdominal infections, pelvic infections, and surgical prophylaxis. Hospital-acquired intra-abdominal infections may require the addition of an aminoglycoside.

Pre-, intra-, and postoperative antibiotics

Endogenous contamination from perforation or rupture of the gastrointestinal tract; exogenous contamination from missiles, knives, or invasive lines and tubes; and immunodepression related to the severity of injury are responsible for the increased infectious complications noted in patients who have undergone laparotomy for abdominal trauma. Perioperative use of clindamycin and an aminoglycoside, a second- or third-generation cephalosporin, or an enhanced-spectrum penicillin is clearly beneficial in lowering the incidence of intra-abdominal and wound infections. A 12- to 48-hour length of administration of antibiotics after operation is as effective as regimens of longer duration, although presently used dosages may be inadequate in severely injured patients. Adjunctive surgical maneuvers such as peritoneal irrigation with saline-containing antibiotic(s) remain controversial. Perioperative use of antibiotic prophylaxis, coupled with early operation and appropriate surgical technique, results in a 4.4% rate of intra-abdominal abscesses and a 5.1% rate of wound infections after laparotomy for abdominal trauma in modern trauma centers.

Management of gastric injuries

The stomach, located in the intrathoracic portion of the abdomen, is well protected from injury. It has a thick wall that is easily mobilized and a rich blood supply that ensures rapid healing of wounds. Although the gastric contents may be contaminated by oral flora immediately after meals, in the resting state, the stomach has few, if any, endogenous organisms. All of these factors make morbidity and mortality associated with penetrating injuries low. In contrast, blunt injuries often cause extensive contamination of the peritoneal cavity with resultant high morbidity and mortality.

Antibiotics for penetrating abdominal trauma: a prospective comparative trial of single agent cephalosporin therapy versus combination therapy

In this prospective, comparative study, 129 patients who sustained penetrating abdominal trauma were randomized to receive preoperatively, and for 3-5 days postoperatively, one of three antibiotic regimens: Group I--cefotaxime (CTX) (2 Gm Q8H), Group II--cefoxitin (2 Gm Q6H), or Group III--clindamycin (900 mg Q8H) and gentamicin (3-5 mg/kg/day in divided doses Q8H). The three groups were similar in terms of the following: age, sex, severity of injury, number of organs injured, colon injuries, shock, blood transfusions, or positive intraoperative cultures. Septic complications occurred as follows: Group I--6.9%, Group II--2.3%, and Group III--6.9%. The three regimens ranked as follows in terms of therapy costs: CTX less than cefoxitin less than clindamycin and gentamicin. It is concluded that single agent therapy with a cephalosporin is preferable to combination therapy on the basis of equivalent effectiveness, lower toxicity, and lower costs.

Colorectal trauma

Colorectal injury remains a source of significant morbidity and mortality. Gunshot and stab wounds are the most common etiologic agents. Diagnosis is usually established on clinical grounds. For the purposes of management, the large bowel can be considered as colon and rectum. Minor colon injuries can be repaired primarily; management of major colon injuries or injuries associated with multiple organ involvement, significant blood loss, or massive contamination should be individualized. Diversion or exteriorization remains the gold standard of treatment when there is any doubt. Rectal injury should be repaired when feasible and diverted and the presacral space drained. Distal rectal washout is of proven merit. Antibiotics provide an important adjunct to therapy. They should be initiated early (preoperatively), ended quickly (12 to 72 hours postoperatively), and provide a broad spectrum of coverage. The treatment of established infection should be guided by bacterial culture. Postoperatively, aggressive support is important for a good outcome. The significant incidence of complications even in the face of optimal management demands continued vigilance and aggressive intervention by the operating surgeon.

More is better. Antibiotic management after hemorrhagic shock

Previous reports suggest that standard antibiotic prophylaxis is ineffective in reducing the incidence of wound infection after hemorrhagic shock. This study investigated the use of larger and longer doses of antibiotic in a model of staphylococcal infection after hemorrhagic shock. Sprague-Dawley rats resuscitated from hemorrhagic shock were injected with either 10(6), 10(8) or 10(10) Staphylococcus aureus subcutaneously. Five treatments were investigated: 1) control (no antibiotic), 2) short-course cefazolin (CEF) (SHORT), 30 mg/kg intraperitoneal (IP), 30 minutes before and 4 hours after inoculation, 3) long-course CEF (LONG), 30 mg/kg IP, 30 minutes before and 4 hours after inoculation, and thereafter, every 8 hours for 3 days, 4) mega-CEF (MEGA) 200 mg/kg IP, 30 minutes before and 4 hours after inoculation, and 5) mega-long CEF (MEGA-LONG), 200 mg/kg IP, 30 minutes before and 4 hours after inoculation, and thereafter, every 8 hours for 3 days. Abscess number, weight, and diameter were measured on Day 7. At the 10(6) inoculum, SHORT was effective in both shocked and unshocked animals. In the 10(10) group, all antibiotic regimens decreased the 100% mortality that followed shock without treatment, but they had little effect on abscess formation. In unshocked rats at the 10(8) inoculum, SHORT was effective in reducing abscess number, diameter, and weight (all p less than 0.05 vs. control). After hemorrhagic shock, SHORT did not decrease abscess frequency, but it did diminish abscess diameter. LONG significantly decreased abscess diameter and abscess weight (both p less than 0.05). After shock, both MEGA and MEGA-LONG reduced abscess number (p less than 0.05 vs. control) and MEGA-LONG was superior to all other regimens at the 10(8) inoculum. These experimental data show that increasing both the dose and duration of antibiotic administration is more effective than standard short-course antibiotic prophylaxis in preventing experimental infection after hemorrhagic shock.

Interferon-gamma restores immune competence after hemorrhagic shock

Hemorrhagic shock increases the susceptibility to infection in both clinical and laboratory settings. Hemorrhagic shock also is associated with a decreased production of interferon-gamma (IFN-gamma), a potent modulator of immune function. We investigated the effect of IFN-gamma both alone and in addition to antibiotic prophylaxis upon infection following hemorrhagic shock. Sprague-Dawley rats were bled to a mean arterial pressure of 45 mm Hg for 45 min and then were resuscitated with shed blood and normal saline. Abscess formation was induced 1 hr later by subcutaneous injection of 1 X 10(8) Staphylococcus aureus. Four treatments were investigated: (1) control; (2) recombinant rat IFN-gamma, 7500 units, 30 min after inoculation and daily for 3 days; (3) cefamandole (CEF) nafate, 30 mg/kg, 30 min before and 4 hr after inoculation; and (4) IFN-gamma + CEF as in (2) and (3). Abscess size, weight, and quantitative bacterial counts were measured 7 days after inoculation. Hemorrhagic shock increased mean abscess size from 11.7 +/- 2.8 to 14.1 +/- 1.9 mm (P less than 0.05), in untreated rats. IFN-gamma alone resulted in minor changes in abscess formation in both shocked and unshocked animals. Shock rendered CEF ineffective in reducing abscess size. IFN-gamma + CEF significantly reduced abscess size (14.1 +/- 1.9 to 8.1 +/- 1.8 mm) and weight (771 +/- 214 to 252 +/- 132 mg) and decreased bacterial count after shock to 12% of control (all P less than 0.05). These data demonstrate that hemorrhagic shock impairs antibiotic efficacy; however, the addition of IFN-gamma restores the ability of host defenses to combat bacterial infection.

Management of infection following intra-abdominal trauma

Intra-abdominal infections following abdominal trauma often involve the gastrointestinal aerobic and anaerobic bacterial flora. These organisms possess various virulence factors and exhibit potential synergy between them. The intra-abdominal infection is biphasic, with the Enterobacteriaceae as the major pathogens in the peritonitis stage, and the Bacteroides fragilis group predominant in the abscess stage. Experiments with animals and experience in human beings support the need to use single or combined antimicrobial agent therapy that is effective against both Enterobacteriaceae and the B fragilis group.

Prophylactic antibiotics in traumatic wounds

There is well-documented evidence justifying, perhaps demanding, the obligatory use of early, anticipatory treatment in open fractures and in penetrating abdominal wounds, and equally convincing evidence that they are not indicated in fractures of the base of the skull with CSF leaks, in thermal injuries, or in simple lacerations. As far as penetrating chest wounds, and bites are concerned, the evidence is perhaps as yet inconclusive, but antibiotics are probably not indicated in these situations.

Preventative antibiotics for penetrating abdominal trauma--single agent or combination therapy?

In this open, prospective, comparative study, 75 patients who sustained penetrating abdominal trauma were randomised to receive 1 of 3 antibiotic regimens preoperatively and for 3 to 5 days postoperatively. Group I received cefotaxime 2g 8-hourly, group II received cefoxitin 2g 6-hourly and group III received clindamycin (900 mg 8-hourly) and gentamicin 3 to 5 mg/kg/day in divided doses 8-hourly. The 3 groups were not statistically different in terms of age, sex, severity of injury, number of organs injured, colon injuries, shock, blood transfusions or positive intra-operative cultures. Septic complications occurred in 8% of patients in group I, in 4% of group II patients and in 8% of group III patients. Cefotaxime was the least costly regimen, followed by cefoxitin, then clindamycin and gentamicin. It may be concluded that single agent therapy with a broad spectrum cephalosporin is preferable to combination therapy on the basis of equivalent effectiveness, less toxicity and lower costs.

Antimicrobial prophylaxis of gastrointestinal surgical procedures and treatment of intraabdominal infections

Antibiotic prophylaxis and treatment regimens ideally are selected on the basis of efficacy, safety, and cost. This review evaluates current, selected literature on antibiotic prophylaxis for colorectal surgery, presumptive antibiotic administration following penetrating abdominal trauma, and treatment of intraabdominal infections. Single-drug regimens with the newer, broad-spectrum agents are assessed and compared with combination regimens; specific regimens are recommended. Colorectal procedures require an antimicrobial agent with activity against both aerobes and anaerobes. Patients undergoing elective colorectal procedures can be adequately protected with an orally administered three-dose regimen of neomycin/erythromycin. Parenteral antibiotic administration is generally not necessary, but, cefoxitin is recommended for nonelective colorectal surgery. The risk of potential infectious complications following penetrating abdominal trauma without colonic perforation is less than with colonic perforation; however, antibiotic therapy that includes activity against aerobes and anaerobes is recommended for all types of penetrating abdominal trauma. Although cephalothin, cefamandole, or cefoxitin alone may be used in abdominal trauma without perforation of the colon, only cefoxitin is recommended as a single-drug alternative to the standard clindamycin/gentamicin regimen in trauma with colonic perforation. Single-drug therapy with cefoxitin or moxalactam can be used successfully as alternatives to the standard regimens of clindamycin/gentamicin or metronidazole/gentamicin in many patients with intraabdominal sepsis. Single-drug regimens reduce the risk of developing adverse effects and are cost-effective. However, if resistant organisms are suspected, or if the patient has been hospitalized for a prolonged period or has multiple organ failure, it may be necessary to supplement cefoxitin therapy with an antibiotic that will enhance coverage against gram-negative aerobes.

Single agent cephalosporin prophylaxis for penetrating abdominal trauma. Results and comment on the emergence of the enterococcus

Multiple studies have shown that the incidence of infectious complications after penetrating abdominal wounds are decreased by the perioperative administration of antibiotics. In this study of three separate single cephalosporin agents (cefotaxime, cefoxitin, and moxalactam) given for a 48 hour period in patients who sustained perforating gastrointestinal wounds, uncomplicated recoveries occurred in 93 percent of all patients. The rates of uncomplicated recovery were significantly different for the three groups; however, patients with major intraabdominal vascular injuries were more common in the cefoxitin-treated group. One disturbing feature was the presence of enterococci in 57 percent of isolates from wound infections and 60 percent of isolates from intraabdominal abscesses. Enterococci as sole isolates were found in one of two wound infections and three of four intraabdominal abscesses in the moxalactam-treated group.

Management of intra-abdominal sepsis

Intra-abdominal sepsis most frequently follows penetrating or blunt abdominal trauma or perforated appendicitis or diverticulitis. The initial leakage of the endogenous gastrointestinal microflora into the peritoneal cavity results in peritonitis and secondary septicemia, which is frequently followed by localized intra-abdominal abscess. These infections are most frequently polymicrobial and relate directly to the unique endogenous microflora at the various levels of the gastrointestinal tract. The treatment of intra-abdominal sepsis is primarily centered around prompt, appropriate surgical intervention. Parenterally administered antibiotics are also required to decrease the chance of local bacterial infection or septicemia. The choice of the appropriate agent(s) to be used initially, before the results of culture and sensitivity reports are available, depends primarily on the clinical presentation and also on whether the intra-abdominal infection occurred in the community or within the hospital setting. Clinical and experimental studies of intra-abdominal sepsis have largely stressed the use of antibiotic agents that have a spectrum of activity effective against the aerobic coliforms and anaerobic Bacteroides fragilis.