Ronald Lee Nichols

Recommendations for preventing the spread of vancomycin resistance: Recommendations of the Hospital Infection Control Practices Advisory Committee (HICPAC)

A rapid increase in the incidence of infection and colonization with vancomycin-resistant enterococci (VRE) has been reported from U.S. hospitals in the last 5 years. This increase poses several problems, including a) the lack of available antimicrobials for therapy of infections due to VRE, since most VRE are also resistant to multiple other drugs, e.g., aminoglycosides and ampicillin, previously used for the treatment of infections due to these organisms, and b) the possibility that the vancomycin resistance genes present in VRE may be transferred to other gram-positive microorganisms such as Staphylococcus aureus. An increased risk of VRE infection and colonization has been associated with previous vancomycin and/or multi-antimicrobial therapy, severe underlying disease or immunosuppression, and intra-abdominal surgery. Because enterococci can be found in the normal gastrointestinal or female genital tract, most enterococcal infections have been attributed to endogenous sources within the individual patient. However, recent reports of outbreaks and endemic infections due to enterococci, including VRE, have shown that patient-to-patient transmission of the microorganisms can occur either via direct contact or indirectly via hands of personnel or contaminated patient-care equipment or environmental surfaces.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Surgical wound infection

Wound infections remain a major source of postoperative morbidity, accounting for about a quarter of the total number of nosocomial infections. Today, many of these infections are first recognized in the outpatient clinic or in the patients home due to the large number of operations done in the outpatient setting. This leads to errors in establishing the true incidence of their occurrence but undoubtedly decreases the overall real cost and length of hospital stay. The pathogens implicated in the development of wound infections remain largely the human microorganisms from the exogenous environment and the endogenous organ microflora. Many perioperative factors have been identified that increase the incidence of the development of postoperative wound infection. Avoidance of these factors as well as the appropriate use of perioperative antibiotic prophylaxis has decreased the incidence of wound infection. During the last decade many studies have reported on the individual risk factors that favor the development of postoperative infectious complications in various surgical procedures. It is hoped that this knowledge may allow for prospective alterations in the preventative and therapeutic modalities in the high-risk patient in the studies designed in the 1990s. The use of effective infection surveillance both in the hospital and in the outpatient setting is mandatory in order to collect meaningful data. The use of computer technology will greatly facilitate the proper surveillance, analysis, and control of infections in the surgical patient.

Antibiotic Prophylaxis in Surgery

Scientific studies conducted during the last 10 years have resulted in a great improvement of our approach to the appropriate use of prophylactic antibiotics in the surgical patient. Errors of the past including faulty timing of the initial dosage as well as prolonged duration of prophylaxis have largely been remedied. Present studies are designed to define the patients within the various subsets of diseases or surgical procedures who are at greatest risk of infection. It is these patients who can be expected to benefit most from the efficacious use of prophylactic antibiotics as well as other preventative measures.

Clinical Presentations of Soft-Tissue Infections and Surgical Site Infections

Skin and soft-tissue infections that usually follow minor traumatic events or surgical procedures are caused by a wide spectrum of bacteria. Less frequently, the infections occur spontaneously, which often is clinically confusing and leads to delays in diagnosis. Most of the infections are self-limited and easily treated with local measures and/or antibiotics. Others are life-threatening, requiring prompt diagnosis and aggressive surgical debridement in addition to the wise choice of antibiotic agents to limit tissue loss and preserve life. Many survivors experience critical tissue losses that may require changes in lifestyle as well as major reconstructive cosmetic surgery. Involvement of antibiotic-resistant gram-positive microorganisms in these infections only increases the difficulty of their treatment and may have a significant influence on the ultimate outcome.

Veterans Administration Cooperative Study on Bowel Preparation for Elective Colorectal Operations: impact of oral antibiotic regimen on colonic flora, wound irrigation cultures and bacteriology of septic complications.

A ten hospital cooperative study comparing prophylactic oral neomycin and erythromycin base versus placebo demonstrated clinical efficacy of the antibiotics in preventing septic complications following elective colon operations. The present report concerns microbiological studies accomplished during this trial. Cultures of colon contents during surgery showed the antibiotic prep reduced concentrations of both aerobes and anaerobes by approximately 105 bacteria/ml. Virtually all major bacterial components of the normal flora were affected. Wound irrigation specimens at the time of closure failed to predict subsequent wound infection, but significantly fewer antibiotic recipients had positive irrigation cultures. Postoperative stool specimens showed that the oral antibiotics did not cause an emergence in resistant forms. Bacteriological studies of postoperative infections indicated that most postoperative infections involved a mixed aerobic-anaerobic flora, and that Bacteroides fragilis accounted for six of eight episodes of bacteremia.

Preoperative prophylactic cephalothin fails to control septic complications of colorectal operations: results of controlled clinical trial. A Veterans Administration cooperative study.

Data obtained from a survey of the membership of the Society for Surgery of the Alimentary Tract and the American Society of Colon and Rectal Surgeons indicated that concomitant administration of oral neomycin-erythromycin base and systemic cephalothin, together with mechanical colon cleansing, was the most popular method of colon preparation. We designed a prospective double blind clinical trial to compare administration of intravenous cephalothin, oral neomycin-erythromycin base, and the combination of both the intravenous and oral antibiotics. Intake of patients to the intravenous cephalothin group was stopped because the data indicated that this method of prophylaxis resulted in significantly higher numbers of septic complications. The incidence of wound infection was 30 per cent and the overall incidence of septic complications was 39 per cent in patients receiving only intravenous cephalothin combined with mechanical colon cleansing. The incidence of wound infection and the overall incidence of septic complications was only 6 per cent in the comparison group, and the differences are highly significant.

Once-Daily, High-Dose Levofloxacin versus Ticarcillin-Clavulanate Alone or Followed by Amoxicillin-Clavulanate for Complicated Skin and Skin-Structure Infections: A Randomized, Open-Label Trial

This study tested whether levofloxacin, at a new high dose of 750 mg, was effective for the treatment of complicated skin and skin-structure infections (SSSIs). Patients with complicated SSSIs (n=399) were randomly assigned in a ratio of 1:1 to 2 treatment arms: levofloxacin (750 mg given once per day intravenously [iv], orally, or iv/orally) or ticarcillin-clavulanate (TC; 3.1 g given iv every 4-6 hours) followed, at the investigators discretion, by amoxicillin-clavulanate (AC; 875 mg given orally every 12 hours). In the clinically evaluable population, therapeutic equivalence was demonstrated between the levofloxacin and TC/AC regimens (success rates of 84.1% and 80.3%, respectively). In the microbiologically evaluable population, the overall rate of eradication was 83.7% in the levofloxacin treatment group and 71.4% in the TC/AC treatment group (95% confidence interval, -24.3 to -0.2). Both levofloxacin and TC/AC were well tolerated. These data demonstrate that levofloxacin (750 mg once per day) is safe and at least as effective as TC/AC for complicated SSSIs.

Use of prophylactic antibiotics in surgical practice

During the last decade great inroads have been made concerning the appropriate use of antibiotic prophylaxis in the surgical patient. Well-controlled, prospective, blinded studies have outlined many of the areas in which antibiotic prophylaxis is of benefit, as well as those clinical situations in which the risks of antibiotic prophylaxis outweighed the expected value. Historically, the most common errors in usage include the widespread use of antibiotic prophylaxis in clean surgery and the faulty timing of administration. The most common error today (in the use of prophylactic antibiotics in surgical practice) is continuation of the agents beyond the time necessary for maximal benefit. In order to appropriately administer prophylactic antibiotics in the various clinical settings on the surgical service, in which this practice has been of proved value, one must be aware of the following nuances including (1) choice of the antibiotic agent based on the type of organisms usually causing infection, (2) route of its administration, (3) the dosage necessary to attain efficacious tissue or serum levels, and (4) the timing of administration which offers the maximum benefits without risking the adverse effects.

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.