The value of adjuvant systemic antibiotic therapy in localised wound infections among hospital patients: a comparative study

In a prospective randomised double-blind controlled trial that involved 73 patients with non-invasive wound infections receiving local wound treatment, the effect of adjuvant systemic antibiotic therapy was compared with that of a placebo. On inspection, more wounds were assessed as clinically clean after administration of an antibiotic than after the placebo was given although this difference was not statistically significant. Microbiological evaluation, however, showed a significantly higher cure of sepsis and elimination of individual organisms (P less than 0.05) after antibiotic therapy. Furthermore, eradication of antibiotic-susceptible organisms was significantly greater than that of resistant organisms (P less than 0.005), indicating adequate penetration of antibiotic into the septic wound exudate. The results suggest that appropriate adjuvant systemic antibiotic therapy in the management of infected wounds promotes bacterial clearance and this may enhance healing of wounds.     

Coronary arterial bypass operations without antibiotic coverage.

In this study, six of 693 consecutive patients in 29 months who underwent only myocardial revascularization, without prophylactic systemic therapy with antibiotics, experienced infection of a clean wound. This incidence of infection (0.86 percent) in such patients is the lowest reported in the literature. Prevention of infection of clean mediastinal wounds in patients undergoing only myocardial revascularization is related to preoperative preparation of the skin and local antibiotic irrigation of the wound, rather than to prophylactic systemic therapy with antibiotics.     

Comparison of the bacterial isolates and antibiotic resistance patterns of elderly nursing home and general community patients

Background: Nursing home‐acquired infections may differ from general community‐acquired infections in bacteriology and antibiotic resistance. However, there are currently limited data on this topic in the Australian setting. Aims: To compare bacterial isolates and antibiotic resistance patterns, from pathology specimens of nursing home and community patients, and to comment on the suitability of empiric antibiotic guidelines for nursing home‐acquired infection. Methods: This was a retrospective cohort study of patients, aged ≥65 years, who resided in either nursing homes or the general community. Patients with a hospital admission in the previous 28 days were excluded. Positive specimen cultures, collected between July 2003 and June 2008 in the Emergency Department and Outpatient Clinics of the Austin Hospital (Melbourne), were examined. The main outcome measures were the bacterial isolates, and their antibiotic resistance patterns, of patients from nursing homes and the general community. Results: Specimens of blood (638), sputum (425), urine (4044) and wound cultures (785) were examined. The bacteriology of blood culture isolates did not differ between the two groups (P= 0.3). However, the bacteriology of sputum, urine and wound cultures differed significantly between the groups (P= 0.025, P < 0.001, P= 0.004 respectively). There were also higher proportions of antibiotic resistance among some bacteria in nursing home patients, especially methicillin resistance among Staphylococcus aureus isolates across all specimen types, and resistance to several empiric antibiotics among Enterobacteriaceae isolates in urine cultures. Conclusion: Empiric antibiotic guidelines appear adequate to treat nursing home‐acquired septicaemia and pneumonia. However, guidelines for urinary tract infections and wound infections may need to be refined.     

Role of antibiotic therapy in diabetic foot management

Antibiotic therapy is not the most important component in diabetic foot ulcer management which should be based on weight bearing avoidance and arterial revascularization. However antibiotic therapy is necessary in presence of extensive deep involvement or systemic signs of infection. Initial antimicrobial treatment depends on bacteria supposed origin. For patients not coming from hospital, the initial choice antibiotic is an amoxicillin/clavulanate agent because it offers optimal coverage for most pathogens involved in those diabetic foot lesions (gram positive cocci, gram negative and anaerobic organisms). For patients at high risk to be infected with nosocomially acquired pathogens, the initial antibiotic therapy must cover methicillin-resistant staphylococci, resistant pseudomonas aeruginosa or enterobacteriae. In all cases, when definitive reliable cultures are reported, initial antibiotic regimens should be revised to narrow the coverage to specific pathogens. In presence of osteomyelitis, a temporary combination of two agents which are known to reach high bone concentrations is necessary, and antibiotic therapy should be continued for at least two months. In other cases, antibiotic treatment duration depends on clinical out come.     

Addition of corticosteroids to antibiotic treatment ameliorates the course of experimental Staphylococcus aureus arthritis

Objective. To evaluate the combined effect of systemic corticosteroid and antibiotic therapy on the course of septic arthritis. Methods. The murine model of hematogenously acquired Staphylococcus aureus arthritis was used. Mice were treated with corticosteroids and antibiotics, and were followed up individually. Arthritis was evaluated clinically and histopathologically. Serum samples and bacterial isolates were also analyzed. Results. The prevalence of arthritis 14 days after the onset of the disease was 22% in the corticosteroid and antibiotic–treated group, as compared with 81% in the control (nontreated) group and 48% in the antibiotic-treated group. The severity of arthritis also decreased in the corticosteroid and antibiotic-treated group, as did the mortality rate. Immunohistochemical analysis revealed a dramatic decrease in T cells and macrophages in the synovium of mice that took the combined therapy. The mechanisms leading to this outcome include the inhibitory effect of corticosteroids on T cell and B cell proliferation and differentiation, such as suppression of interferon-γ (IFNγ) production. Serum levels of IFNγ were decreased 4-fold in the antibiotic-treated group compared with the controls; a 15-fold decrease was observed in the corticosteroid and antibiotic–treated animals. In addition, serum NO₃⁻ was significantly decreased in mice treated with antibiotics (P ≤ 0.05), as well as in mice treated with corticosteroids and antibiotics (P ≤ 0.001). Conclusion. Systemic corticosteroid administration along with antibiotic therapy had beneficial effects on the course and outcome of S aureus arthritis.     

Single-dose metronidazole vs 5-day multi-drug antibiotic regimen in excision of pilonidal sinuses with primary closure: a prospective, randomized, double-blinded pilot study

Aim To compare infection-related wound complications following excision of pilonidal sinuses with primary closure using either single-dose intravenous (i.v.) administration of metronidazole preoperatively or a broad-spectrum multi-drug regimen.Patients and methods This is a double-blinded study wherein 50 patients were randomized into receiving either single-drug (metronidazole 500 mg i.v.) prophylaxis preoperatively or multi-drug cover (cefuroxime 1.5 g i.v. and metronidazole 0.5 g i.v. preoperatively, and co-amoxiclav 375 mg orally 8-hourly postoperatively for 5 days). They were reviewed at 1, 2 and 4 weeks postoperatively. Wounds were graded as follows: I, healthy; II, redness and swelling of edges; III, abscess in relation to a suture; IV, spreading wound infection; and V, wound breakdown. Other factors considered were the distance from the lowest wound margin to the anal verge and previous local surgery.Results Fifty patients (38 men and 12 women, mean age 27 years) underwent pilonidal sinus surgery. At week 1, there was no difference in wound infection rates (p=0.9). However, there were significantly more wound infections in the single-drug group at week 2 (p<0.0001) and week 4 (p=0.03). Seventy-two per cent of all patients had complete wound healing at week 4. Distance from the anal verge and previous surgery did not affect wound infection rates (p≥0.2). Treating such complications costs $73,219.20 per 100 patients.Conclusion A broad-spectrum 5-day regimen is superior to ‘single-shot’ antibiotic prophylaxis in preventing infection-related wound complications. However, this study needs to be conducted in a larger number of patients to have statistical power.     

Infection in chronic wounds: controversies in diagnosis and treatment

Chronic wounds all have bacterial contamination, which will not impair healing. Wound contamination must be distinguished from wound colonization and infection. Bacterial infection in wounds depends on the number of organisms present, their virulence, and host resistance. The most important indicators of infection are both local and systemic host characteristics and a holistic assessment of the patient. Several specimen collection and culture techniques are available to measure bacterial burden in the chronic wound. Advantages and disadvantages of each one discussed along with a rational approach to systemic antibiotic therapy. The presence of foreign material such as skin grafts or skin substitutes may lower the bacterial burden that may impair healing from 1.0 x 10(6) colony-forming units to 1.0 x 10(5) or less. The benefits of wound debridement, wound irrigation, and local nonantibiotic modes of treatment have been proven but the use of topical antibiotics and antiseptics requires further assessment. More widespread use of multiple nonantibiotic modalities of treatment for infected chronic wounds and rational antibiotic prescribing should reduce the risk of future antimicrobial resistance such as MRSA.     

Infective complications according to duration of antibiotic treatment in acute abdomen.

INTRODUCTION: Adjuvant antibiotic therapy for acute abdominal conditions is widely used. Its timing, duration, dose and spectrum, however, are not homogeneous amongst surgeons and prolonged courses are often used despite the unproven benefits of this practice. OBJECTIVE: To evaluate use and compare duration of antibiotic treatments in acute abdominal surgery. METHODS: Retrospective cohort study. The medical records of 290 patients who underwent operations for acute abdomen from July 1998 to July 1999 in a teaching hospital were reviewed. The pattern of antibiotic use and rates of postoperative complications were evaluated, along with surgical diagnosis, degree of contamination/infection, and incidence of postoperative complications. The patients were stratified according to the degree of contamination/infection noted during the operation. The study population was divided in two groups according to the duration of antibiotic use (cut-off point at the median antibiotic use in days, for each group of contamination/infection degree), and outcomes were compared. RESULTS: The degree of contamination/infection was significantly associated with an increased risk of wound infection, intra-abdominal abscess, postoperative infective complications and overall postoperative complications (p < 0.001). A long course of antibiotics was not associated with lower infective complication rates. CONCLUSIONS: Shorter courses of antibiotic therapy based on the degree of contamination/infection seem to be safe. A prospective study should confirm this hypothesis.     

Systemic Timentin® is superior to oral tinidazole for antibiotic prophylaxis in elective colorectal surgery

A prospective, randomized, single-blind, controlled clinical trial was undertaken to compare two different prophylactic antibiotic regimens in patients undergoing elective colorectal surgery. Systemic Timentin^®, a combination of ticarcillin and the beta-lactamase inhibitor clavulanic acid, was assigned to 101 patients. Oral tinidazole, an agent active only against anaerobic bacteria, was assigned to 102 patients. The wound infection rate was 2.4 percent in the patients receiving Timentin and 14 percent in those receiving tinidazole (P=0.01). Multivariate analysis of factors affecting the wound infection rate showed that the only factor that independently reached statistical significance was the prophylactic antibiotic used. The mortality of patients receiving Timentin prophylaxis was 3.4 percent compared with 8.9 percent of those receiving tinidazole (P=0.15). The clinical anastomotic leakage rate was 1.3 percent in patients receiving Timentin and 13 percent in those receiving tinidazole (P=0.01). These results, together with those of two previously published clinical trials by this group, indicate that antibiotic prophylaxis in elective colorectal surgery should consist of a short course of an agent effective against both aerobic and anaerobic bowel flora.     

Prophylactic antibiotic treatment in acute necrotizing pancreatitis: Results from a meta-analysis

Objective. The effect of prophylactic antibiotic treatment on infection and survival of acute necrotizing pancreatitis (ANP) remains uncertain. The aim of this study was to assess the long-term efficacy of prophylactic antibiotic treatment for ANP. Material and methods. Searches were carried out of electronic databases including Medline, EMBASE, the Cochrane Controlled Trials Register, the Science Citation Index, and PubMed (updated to December 2007), and manual bibliographical searches were also conducted. A meta-analysis of all randomized controlled trials (RCTs) comparing prophylactic antibiotic treatment with placebo or no treatment was performed. Results. Eight RCTs including 540 patients were assessed. The outcomes included infected necrosis, death, non-pancreatic infection, surgical intervention, and length of hospital stay. Prophylactic antibiotic use leads to a significant reduction of infected necrosis (relative risk (RR) 0.69, 95% CI, 0.50–0.95; p=0.02), non-pancreatic infections (RR 0.66 95% CI, 0.48–0.91; p=0.01), and length of hospital stay (p=0.004) but was not associated with a statistically significant reduction in mortality (RR 0.76 95% CI, 0.50–1.18; p=0.22) and surgical intervention (RR 0.90 95% CI, 0.66–1.23; p=0.52). In a subgroup analysis, carbapenem was associated with a significant reduction in infected necrosis (p=0.009) and non-pancreatic infections (p=0.006), whereas other antibiotics were not. Conclusions. Prophylactic antibiotic treatment is associated with a significant reduction of pancreatic or peripancreatic infection, non-pancreatic infection, and length of hospital stay, but cannot prevent death and surgical intervention in acute necrotizing pancreatitis.     

ICU-acquired nosocomial infection: impact of delay of adequate antibiotic treatment

In order to measure the impact on survival of the early introduction of adequate antibiotic treatment for nosocomial bacteremia and pneumonia, a retrospective, cohort study was carried out over a period of 17 months in a 6-bed respiratory ICU. All patients presenting with a first episode of ICU-acquired nosocomial bacteremic infection (Centers for Disease Control criteria) or pneumonia [BAL culture > or = 10(4) colony-forming units (CFU)/ml or protected specimen brush culture > or = 10(3) CFU/ml] were included. The organ failure score (Fagon criteria) was recorded on the day of diagnosis. Adequate antibiotic treatment was defined by the sensitivity of each etiologic organism to at least 1 prescribed antibiotic. A total of 25 patients (Simplified Acute Physiology Score II = 44) were included in the study with pneumonia (n = 17) or bacteremia (n = 8), on average 6.5 +/- 4.6 d after admission. At the time of diagnosis, 23 patients were receiving mechanical ventilation. The overall mortality rate was 48% and was significantly associated with the length of time without adequate antibiotic treatment (p = 0.011) and the number of organ failures on the day of diagnosis (p = 0.017). Adequate antibiotic treatment only had an impact on survival if it was started within the first 24 h after sampling (p < 0.02 on Day 0 and < 0.04 on Day 1). On the day of diagnosis, a failure score > 2 was associated with increased mortality (p = 0.009). After adjusting for the number of organ failures, the length of time without adequate antibiotic treatment remained associated with mortality (< or = 2 organ failures, p < 0.02; > 2 organ failures, p = 0.05). This study suggests that, during the course of nosocomial pneumonia and bacteremia, the time at which adequate antibiotic treatment is started is a key factor influencing survival.     

A controlled study comparing the conventional treatment of idiopathic anorectal abscess with that of incision,curettage and primary suture under systemic antibiotic cover

Summary The treatment of anorectal abscess by deroofing and packing on an initial inpatient basis has been compared in a controlled trial with that of incision curettage and primary suture under systemic antibiotic cover in the Accident and Emergency Department. Over a three-year period 219 patients with anorectal abscess were randomly allocated to one or other treatment and subsequently followed up in a rectal clinic. In terms of the time taken for complete healing and the periods lost from work postoperatively, the method of incision, curettage and primary suture under systemic antibiotic cover was found to be significantly superior, without any increased risk of recurrence of the abscess or of subsequent fistula formation.     

Effect of antibiotic treatment on vegetation size and complication rate in infective endocarditis

Background: Infective endocarditis is associated with significant morbidity and mortality, with valvular destruction, and with congestive heart failure. Embolic events are more common in patients with echocardiographically discernible vegetations, especially when vegetations are >10 mm in diameter. Hypothesis: The objective of the study was to follow vegetation morphology during native valve endocarditis, to compare it with the clinical course and antibiotic treatment chosen, and to evaluate whether the impact on vegetation size and complication rate of antibiotic regimens differed in patients with positive and negative blood cultures. Methods: The effect of different antibiotic regimes on vegetation size monitored by using transesophageal echocardiography was evaluated in 183 patients with echocardiographic evidence of infective endocarditis. A total of 223 vegetations attached to the aortic or mitral valves were detected using the transesophageal approach. The patients were followed for a mean of 76 weeks and underwent a minimum of two consecutive transesophageal echocardiographic examinations. Results: Treatment with different kinds of antibiotics corresponded with significant differences in vegetation size; vancomycin-associated treatment was related to a 45% reduction, ampicillin to a 19% reduction, penicillin to a 5% reduction, penicillase-resistant drugs to a 15% increase, and cephalosporin to a 40% increase in vegetation size. Multivariate analysis showed that penicillin, cephalosporin, and penicillase-resistant drug treatments were associated with an increased embolic risk, vancomycin treatment with abscess formation, and cephalosporin medication with increased mortality. Plotting changes in vegetation size against the incidence of embolism and mortality, linear regression analysis suggested a 40–50% reduction in vegetation size, thereby greatly reducing the risk of embolism and mortality. Conclusion: Our study shows that different antibiotics have different effects on vegetation size. The highest complication rate was observed when vegetations significantly increased in size during antibiotic treatment. Especially in culture-negati ve patients, monitoring vegetation size by means of transesophageal echocardiography may prove to be useful for estimating the efficacy of antibiotic treatment.     

Conservative therapy adapted to findings of superficial chronic venous ulcers

A successful treatment of venous ulcers represents a special clinical challenge. The following conservative wound management of a high-risk patient presents an alternative to primary surgical treatment. A patient of 79 years in reduced general state with multiple underlying concomitant diseases is hospitalized with superinfected, necrotic and painful ulcers. Due to the severe morbidity of the patient the regular therapy of the underlying venous insufficiency consisting of stripping of great saphenous vein and ligation of perforator veins, is contraindicated. After interdisciplinary discussion conservative therapy is carried on. The conservative therapy includes initial local debridement, moist wound-healing dressings, compression therapy, systemic antibiotic and analgesic therapy, completed by stabilization of patient's general state. In regular intervals a photographic documentation of the wound is carried out. The period of treatment and observation is 63 days. Due to conservative wound management a clear improvement of the wound condition and of the patient's general state is observed. The period needed for change of wound dressing can be reduced from 2 hours to 30 minutes. The painscore is reduced from 8/10 to 4/10 as well as the analgesic need. The photographic documentation shows a clear progress of healing within 9 weeks. Under antibiotic therapy and conservative wound management the increased inflammation parameters are declining. By choosing a conservative therapeutical regime adapted to clinical findings superinfected, chronic venous ulcers are turned into a stable condition.     

Meta-analysis of randomized, controlled trials of antibiotic prophylaxis before percutaneous endoscopic gastrostomy

OBJECTIVES: We sought to review the published literature on the value of antibiotic prophylaxis for the prevention of wound infection that occurs after percutaneous endoscopic gastrostomy. We also sought by meta-analysis to estimate the efficacy of antibiotic prophylaxis in preventing wound infection. METHODS: We performed a fully recursive literature search for randomized, controlled trials of antibiotic prophylaxis against wound infection occurring after percutaneous endoscopic gastrostomy. Relative and absolute risk reductions and the numbers needed to treat were derived for individual trials and pooled data. RESULTS: We identified seven trials, two of which did not find a statistically significant benefit of antibiotic prophylaxis. After pooling, antibiotic prophylaxis was found to reduce the relative and absolute risk of wound infection by 73% and 17.5%, respectively. The number needed to treat to prevent one wound infection was 5.7 (95% confidence interval = 4.4-8.0). CONCLUSION: A single intravenous dose of a broad-spectrum antibiotic, given approximately 30 min before percutaneous endoscopic gastrostomy is effective in reducing the incidence of peristomal wound infections.     

Therapie des Dekubitus beim älteren Patienten

The treatment of pressure sores in elderly patients requires careful documentation and a comprehensive treatment plan, which takes into account the patient's overall situation. The treatment has to be evidence based. At the moment only three recommendations can be based on two or more prospective, randomized clinical studies: to use a dressing to maintain a moist environment at the wound/dressing interface, to reduce the risk of infection and enhance wound healing by hand washing, wound cleansing and debridement and to institute a systemic antibiotic treatment for patients with advancing cellulitis, sepsis and osteomyelitis. For other treatment options such as topical negative pressure, maggot therapy, electromagnetic therapy, therapeutic ultrasound or growth factors, the data at present are not sufficient to support general use in pressure sore treatment.     

Intraincisional antibiotics in laparotomy wounds

Concentrations of ampicillin after intraincisional instillation in laparotomy wounds were measured in ten patients undergoing appendectomy. Ampicillin, 1 gm, was instilled under the fascia and 1 gm in the subcutaneous space during wound closure. Wound secretion was collected every two hours during the first 24 postoperative hours by cannulation of a fine perforated drain placed in the subcutaneous space. Ampicillin was determined by a disk diffusion method. During the first eight hours the median concentration of ampicillin in wound secretion exceeded 1000 microgram/ml; 14 hours and 20 hours after wound closure the median concentrations were 73 and 14 microgram/ml, respectively. The effect of ampicillin in high concentrations on “resistant” strains ofBacteroides fragilis was demonstrated in anin vitro experiment. It is concluded that in colorectal surgery the effect on wound sepsis of intraincisional antibiotics as an addition to systemic antibiotic prophylaxis should be evaluated in a clinical trial.