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Soft tissue infections are classified as local or spreading. Spreading soft tissue infections are potentially life-threatening conditions, requiring prompt diagnosis and treatment. The information presented is based on a literature review and the authors' clinical experience. Diagnosis of soft tissue infections is aimed at determining the level of infection (skin, fascia, muscle) and whether necrosis is present. The bacteriology of these infections is varied and is of secondary importance. Treatment of skin infections that have no dead tissue is with antibiotics alone. Infections at the fascial or muscle level and those with necrosis at any level require surgical debridement and adjuvant antibiotics. The feet of diabetic patients are prone to planter forefoot ulcers associated with tissue destruction and infection. The vast majority are caused by mechanical factors. If local immune defenses are adequate, bacterial colonization occurs without infection. Most diabetic foot ulcers will respond to relief of pressure, which may require total contact casting. Antibiotics and debridement are required in infected or deep ulcers, or when the ulcer does not respond to total contact casting.

INTRODUCTION: 'Pharmacodynamics' refers to the relationship of drug concentrations in serum or tissues to effects on biologic systems. Concepts used to describe antimicrobial pharmacodynamics include the minimal inhibitory concentration (MIC), the minimal bactericidal concentration (MBC), and serum bactericidal titers (SBT), as well as post-antibiotic effect. METHODS: Pertinent published literature was identified through a MEDLINE search. RESULTS: Aminoglycosides have a concentration-dependent effect on bacteria killing and possess a relatively long postantibiotic effect. Given these characteristics, single-daily dosing, where the total daily dose with a traditional aminoglycoside regimen is given as one dose, may be more efficacious compared with more frequent dosing. For beta-lactam antimicrobials, bacterial killing is related to the duration of time that the free drug concentration exceeds the bacterial MIC. Beta-lactam antimicrobials have been shown to have no, or a short postantibiotic effect. Beta-lactam antimicrobials may be more effective when administered as continuous intravenous infusions. CONCLUSIONS: Pharmacodynamic variation may result from differences in drug sensitivity among individuals and the nature of the interaction between antimicrobials and microorganisms. Proper use of pharmacokinetic and pharmacodynamic principles can result in more effective and less toxic antimicrobial regimens. Am J Surg. 1996;171:615--622.

Pneumonia acquired during hospitalization (nosocomial) is the leading cause of death from hospital-acquired infection. This condition is usually caused by aspiration of gram-negative bacilli, often in patients with decreased immune defenses. A prospective study was undertaken of 300 patients with intra-abdominal abscess to compare the outcomes of patients with nosocomial pneumonia with the outcomes of patients without pneumonia but with recurrence of intra-abdominal abscess. There were 34 patients who were admitted to the hospital with pneumonia; these had a mortality of 44 percent and were excluded from the study. The mortality of 171 patients with no nosocomial pneumonia and no recurrent intra-abdominal abscess was 20 percent (34 patients). The 36 patients with recurrent abdominal abscess had a 17 percent mortality; 47 patients with nosocomial pneumonia had a 53 percent mortality. There were and additional 12 patients who had both nosocomial pneumonia and recurrent intra-abdominal abscess; mortality in this group was 75 percent. Several risk factors were identified: APACHE II score (Acute Physiology and Chronic Health Evaluation), the need for assistance with respiration, steroids, generalized peritonitis, and need for surgery. It is concluded that nosocomial pneumonia is an independent risk factor associated with significant mortality, compared with recurrence of intra-abdominal abscess. (Consumer Summary produced by Reliance Medical Information, Inc.)

The argument that minimally symptomatic hernias may be left unoperated upon is well supported by data described by Preshaw (1) and cited in my article, (2) that show irreducibility rates [...]

A 55-year-old man describes first feeling a painful lump on the left side of his groin while playing soccer. He says it does not interfere with his work as a [...]

Abstract. Abdominal infections are treated by resuscitation, abdominal drainage, control of the source of infection, and antimicrobial agents. Ideally, antimicrobial therapy is active against expected pathogens, safe and effective in clinical trials, inexpensive, and unlikely to promote drug resistance. Numerous single-agent and combination-drug regimens have been efficacious in clinical trials, based on coverage of: Escherichia coli and Bacteroides species, the predominant pathogens isolated. Whether expanded antimicrobial coverage is required, especially in hospital-acquired infections, is controversial. Candida infections should be treated with antifungal therapy in patients with recurrent abdominal infections, immunosuppressed patients, and those with candidal abscesses. Most agents have few serious adverse effects; aminoglycosides are the least expensive agents but cause nephro- and ototoxicity. There is little information on the promotion of drug resistance in this condition. Recent developments include the introduction of ticarcillin/clavulanic acid, ampicillin/sulbactam, piperacillin/tazobactam, meropenem, aztreonam/clindamycin, and ciprofloxacin/metronidazole; success with once-daily aminoglycosides; evidence that antibiotics limit infectious complications of pancreatitis; controversy over the value of diagnostic cultures; the use of oral therapy; evidence in favor of shorter courses of treatment; and the introduction of pharmacoeconomic studies. Clinical investigators are challenged to improve drug trials by stratifying and controlling for the adequacy of surgical intervention.

The effects of free versus liposomal cefoxitin on various physiological parameters in a porcine model of Gram-negative intra-abdominal sepsis were evaluated. Four different doses of Escherichia coliinoculum mixed with sterile pig feces were used (108, 109, 1010, and 1011cfu/animal), and the most consistent hemodynamic changes were observed with an inoculum of approximately 1011bacteria/20 kg animal. Two treatment groups were established as follows: free cefoxitin (n = 9) and liposomal cefoxitin (n = 9). All animals were maintained under anesthesia for the duration of the study, and then euthanized 24 h following intra-abdominal inoculation. The inoculated and nontreated animals showed increases in heart rate, mean pulmonary arterial pressure, systemic and pulmonary vascular resistance, and decreases in mean systemic arterial pressure and cardiac index. These changes were significant (p< .05) compared with a control group injected with normal saline. Liposomal cefoxitin-treated animals showed significantly lower decreases in mean systemic arterial pressure and increases in heart rate (p< .05) compared with both the inoculated nontreated and free cefoxitin-treated groups. Both liposomal and free cefoxitin significantly modulated the mean pulmonary arterial pressure compared with the inoculated nontreated animals (p< .05). Acidosis that developed during intra-abdominal infection diminished 6 h following the first dose of liposomal cefoxitin (p< .05). The results of these experiments demonstrate that liposomal cefoxitin exerts a beneficial modulation of some of the hemodynamic disturbances during intra-abdominal Gram-negative sepsis.

Operation for intra-abdominal infection aims to prevent further contamination of the abdominal cavity, treat the underlying source of infection, and prevent residual or recurrent sepsis by cleaning the peritoneal cavity. Aggressive attempts at early diagnosis are warranted, even if laparotomy is occasionally required for diagnostic as well as therapeutic purposes. Conversely, the degree to which more aggressive methods of peritoneal debridement are helpful is the subject of great controversy that can be resolved only by prospective, randomized multicenter trials. Current standard treatment consists of closure, drainage, or excision of the source of contamination; intra-operative saline or antibiotic lavage of the peritoneal cavity; fascial closure; and secondary or delayed primary closure of the wound.