Jeffrey W. Smith

Risk of Infection after Penetrating Abdominal Trauma

To identify the risk factors for the development of postoperative septic complications in patients with intestinal perforation after abdominal trauma, and to compare the efficacies of single-drug and dual-drug prophylactic antibiotic therapy, we studied 145 patients who presented with abdominal trauma and intestinal perforation at two hospitals between July 1979 and June 1982. Logistic-regression analysis showed that a higher risk of infection (P less than 0.05) was associated with increased age, injury to the left colon necessitating colostomy, a larger number of units of blood or blood products administered at surgery, and a larger number of injured organs. The presence of shock on arrival, which was found to increase the risk of infection when this factor was analyzed individually, did not add predictive power. Patients with postoperative sepsis were hospitalized significantly longer than were patients without infection (13.8 vs. 7.7 days, P less than 0.0001). Both treatment regimens--cefoxitin given alone and clindamycin and gentamicin given together--resulted in similar infection rates, drug toxicity, duration of hospitalization, and costs.

Efficacy of a β-lactamase Inhibitor Combination for Serious Intra-abdominal Infections

A double-blind trial was conducted in 385 patients with suspected bacterial intra-abdominal infections to compare the efficacy and safety of ampicillin-sulbactam with cefoxitin. Patients were randomized to receive either 3 g ampicillin-sulbactam (2 g ampicillin-1 g sulbactam), or 2 g cefoxitin, every 6 hours. To be evaluable, patients had to demonstrate positive culture evidence of peritoneal infection at the time of operation. A total of 197 patients were evaluable for clinical efficacy. The two treatment groups were comparable in demographic features and in the presence of risk factors for infection. Clinical success (absence of infection and of adverse drug reaction) was observed in 86% of patients in the ampicillin-sulbactam group and 78% in the cefoxitin group. Eradication of infection occurred in 88% of the ampicillin-sulbactam group and 79% of the cefoxitin group. There were no differences in the nature or frequency of side effects observed in the two groups. Ampicillin-sulbactam demonstrated no difference in safety or efficacy when compared with cefoxitin in the treatment of serious intra-abdominal infections of bacterial origin.

Intragastric microbial colonization in common disease states of the stomach and duodenum.

Forty-nine patients undergoing elective or emergent gastric surgery have been included in this study. Gastric needle aspiration was performed at the time of surgery in each case, followed by qualitative aerobic and anaerobic bacteriologic analysis. In 18 patients undergoing elective operation for chronic non-obstructing duodenal ulcer a gastric microflora was present in only three patients and no postoperative wound infections were observed. In 29 of 31 patients, in the other groups of patients with bleeding or obstructing duodenal ulcer or in those with gastric ulcer or malignancy, intragastric micro-organisms were present. Six of the 7 postoperative wound infections which developed in these groups of patients were due to one of the same bacteria isolated at the time of original needle aspiration. It appears that the endogenous intragastric microflora is a significant factor in the development of postoperative wound sepsis following gastric resection, in those groups of patients with a compromise of their normal gastric antibacterial inhibitory mechanisms.

Autotransfusion of potentially culture-positive blood (CPB) in abdominal trauma : preliminary data from a prospective study

Increased use of autotransfusion for traumatic hemorrhage may reduce amounts of banked blood needed for severe injuries. Autotransfusion is standard for traumatic hemothorax, but has been limited for abdominal injuries. This prospective study used microbiologic data from 152 patients with intestinal injuries. Where anticipated blood loss was greater than 1,000 mL, blood from the peritoneal cavity was cultured, washed, concentrated, and recultured before reinfusion. Infection rates were stratified using the Penetrating Abdominal Trauma Index (PATI). Fifty patients with PATI greater than 20 who received banked blood (group I) (mean: 1,800 mL) were compared with 20 patients (group II) who received autotransfused, potentially culture-positive blood (CPB) (mean: 3,900 mL). Wound infection rates were identical in both groups (25%). No statistically significant increase was found in site-specific infection risk when severity of injury was stratified according to PATI. Bacteremias, pulmonary infections, and urinary infections were not caused by bacteria cultured from autotransfused blood. We conclude that washed CPB may be autotransfused without significantly increased risk of infection in patients with severe abdominal injuries.

Efficacy of antibiotic prophylaxis in high risk gastroduodenal operations

A double-blind, prospective and randomized clinical trial of the efficacy of antibiotic prophylaxis in gastroduodenal operations was studied in 39 patients over an 18 month period. All patients had clinical features that placed them at high risk for the development of postoperative wound or intraabdominal sepsis. In the placebo group of 20 patients seven gastric-related infections developed, while 1 of the 19 patients who received perioperative cefamandole had one gastric-related infection (p less than 0.01). The responsible microorganisms were those that are normal components of the oral or intestinal microflora. Nongastric-related infections and deaths did not differ significantly in the two study groups. The results of this study confirm the efficacy of the use of short-term perioperative antibiotic prophylaxis in patients undergoing gastroduodenal surgery for bleeding duodenal or gastric ulcer, obstructing duodenal ulcer, gastric ulcer or malignancy.

Peritonitis and intraabdominal abscess: an experimental model for the evaluation of human disease.

Abstract An economical, reproducible experimental model of intraabdominal sepsis in rats has been developed. This model was produced by placing varying amounts of human fecal material within gelatin capsules, which were then surgically placed within the peritoneal cavities of rats. The type of intraabdominal sepsis produced varied according to the amount of inoculum introduced. The full spectrum of sepsis produced was similar to that seen in human peritonitis and intraabdominal abscess formation. This model is suitable for and is presently being used to evaluate the efficacy of the various antibiotic schemes currently used in the treatment of human intraperitoneal infections.

Evaluation of the protective value of hospital gowns against blood strike-through and methicillin-resistant Staphylococcus aureus penetration

BACKGROUND Hospital gowns protect patients and health care workers from exposure to blood and other infectious materials. Previous studies have shown that certain gowns do allow blood strike-through. Because of worldwide increases in the incidence of Staphylococcus aureus infections, especially with methicillin-resistant strains, there is now increased concern regarding bacterial transmission through gowns. METHODS This study evaluated six gown types used in hospitals (one disposable cover or isolation gown, three disposable operating room gowns, and new and washed reusable operating room gowns). Gowns were evaluated for dry spore and S. aureus filtration efficiencies and were subjected to 20 time-pressure combinations with methicillin-resistant S. aureus-spiked blood (10(4)/ml) to evaluate blood strike-through and passage of methicillin-resistant S. aureus. RESULTS Blood strike-through was lowest with disposable operating room gowns 1 and 2 (polypropylene). Disposable operating room gown 3 (polyester-wood pulp) showed the greatest strike-through and overall passage of methicillin-resistant S. aureus. Operating room gowns 1 and 2 showed minimal bacterial passage, whereas the disposable cover (polypropylene) only allowed passage at pressures greater than 1 psi. Bacterial filtration efficiency testing showed operating room gowns 1 and 2 to be the most protective; operating room gown 3 and both reusable (cotton) gowns were the least protective. Dry spore passage was greatest for reusable gowns. CONCLUSION Different hospital gowns offer varying degrees of protection against fluid strike-through or bacterial passage. Gowns therefore should be chosen according to the task performed and conditions encountered.

Effects of commonly used bowel preparations on the large bowel mucosal-associated and luminal microflora in the rat model

Studies of colonic microflora have indicated there are two distinct populations, one intraluminal and one mucosal surface-associated. This investigation further characterizes the mucosal surface microflora and assesses the effects of common preoperative bowel preparations on both microflora. Quantitative and qualitative bacterial cultures and scanning electron microscopy were used to study the microflora in five groups of seven rats each: control; intraoperative colonic instillation of ten percent povidone-iodine for 20 minutes; mechanical preparation with magnesium citrate; mechanical preparation followed by intramuscular cefoxitin (30 milligrams per kilogram) one hour preoperatively; and mechanical preparation followed by oral neomycin sulfate and erythromycin base (15 milligrams/kilogram each) given by gavage tube 18, 14, and 4 hours preoperatively. Microflora on the mucosal surface was visualized by scanning electron microscopy in all groups except the neomycin/erythromycin group. Results showed fewer bacterial isolates recovered from the mucosal surface compared with the lumen, as well as several log10 units lower for each bacterial classification. The greatest suppression of both microflora was seen in the neomycin/erythromycin group. Total aerobic and anaerobic luminal counts decreased by 3.7 (P< 0.009) and 6.3 (P < 0.009) log10 units, while total aerobic and anaerobic wall counts decreased by 2.3 (P < 0.009) and 2.8 (not significant) log10 units, respectively. Lesser reductions were noted in the povidone-iodine group (P< 0.009,P< 0.009,P< 0.009, andP < 0.048, respectively). There were no statistically significant reductions in either total aerobic or anaerobic counts in the mechanical preparation or cefoxitin groups. These results indicate that neomycin/erythromycin is the most effective regimen in reducing both microflora.

Comparison of the fecal microflora of Seventh-Day Adventists with individuals consuming a general diet. Implications concerning colonic carcinoma.

Qualitative and quantitative fecal microflora was studied in a double blind fashion in 28 subjects. Fourteen were Seventh-Day Adventists, who were strict vegetarians, while the remaining 14 subjects were individuals consuming a general western diet. No statistically significant differences were identified in the fecal microflora of the two groups. The bacteriologic analysis included total aerobes and total anaerobes as well as each of the major fecal aerobes and anaerobes. This study seems to indicate that the dietary intake of animal fat and protein does not significantly alter the fecal microflora, a possibility which has previously been suggested as being part of the explanation for the higher incidence of colonic carcinoma in those who consume meat compared with vegetarians. It does not, however, invalidate the concept that dietary animal fat does increase bile acid degradation within the gastrointestinal tract, a factor which has been related to colon cancer. Future studies should be directed at identifying the factors that may be present in the gastrointestinal tracts of vegetarians which modify the ability of their colonic microflora to degrade bile acids, an essential step in the production of intraluminal carcinogens or co-carcinogens.

Septic Complications Following Gastric Surgery: Relationship to the Endogenous Gastric Microflora

The microflora of the stomach is derived from both the ingestion of food and saliva and the reflux of proximal intestinal contents through the pylorus. Normally, this microflora is inhibited by gastric acid and normal gastric motility. In disease states, however, such as bleeding or obstructing duodenal ulcer, gastric ulcer or carcinoma, the level of gastric acid is reduced or the gastric motility is altered. Thus, endogenous microflora persists and often becomes the source of postoperative wound infections following gastric resection.