Cost-effectiveness of ampicillin/sulbactam versus imipenem/cilastatin in the treatment of limb-threatening foot infections in diabetic patients

The Epidemiology of Antibiotic-Related Adverse Events in the Treatment of Diabetic Foot Infections: A Narrative Review of the Literature

The use of antibiotics for the treatment of diabetic foot infections (DFIs) over an extended period of time has been shown to be associated with adverse events (AEs), whereas interactions with concomitant patient medications must also be considered. The objective of this narrative review was to summarize the most frequent and most severe AEs reported in prospective trials and observational studies at the global level in DFI. Gastrointestinal intolerances were the most frequent AEs, from 5% to 22% among all therapies; this was more common when prolonged antibiotic administration was combined with oral beta-lactam or clindamycin or a higher dose of tetracyclines. The proportion of symptomatic colitis due to Clostridium difficile was variable depending on the antibiotic used (0.5% to 8%). Noteworthy serious AEs included hepatotoxicity due to beta-lactams (5% to 17%) or quinolones (3%); cytopenia's related to linezolid (5%) and beta-lactams (6%); nausea under rifampicin, and renal failure under cotrimoxazole. Skin rash was found to rarely occur and was commonly associated with the use of penicillins or cotrimoxazole. AEs from prolonged antibiotic use in patients with DFI are costly in terms of longer hospitalization or additional monitoring care and can trigger additional investigations. The best way to prevent AEs is to keep the duration of antibiotic treatment short and with the lowest dose clinically necessary.

Efficacy and Safety of Different Antibiotic Therapies for Bone and Joint Infections: A Network Meta-analysis of Randomized Controlled Trials

BACKGROUND

Although an increasing number of antibiotics are being used to treat bone and joint infections, their specific efficacy remains controversial. Thus, we aimed to systematically compare the efficacy and safety of antibiotic therapies for orthopedic infections.

METHODS

PubMed, Embase, The Cochrane Library, and Web of Science databases were searched from inception to April 2022. Two authors independently and rigorously conducted the screening, data extraction, and quality assessment of the relevant studies. All the extracted data were evaluated using traditional metaanalysis and network meta-analysis by STATA SE 16.0.

RESULTS

A total of eleven randomized controlled trials (RCTs) involving 1,063 patients were included for data analysis. The analysis results from the NMA indicated that in terms of the clinical effectiveness rate, linezolid (OR: 1.75, 95% CI: 1.01 to 3.02) showed significant efficacy compared to ampicillin/sulbactam. With regard to the microbiological eradication rate, linezolid showed significant efficacy compared to cephalosporins (OR: 8.13, 95% CI: 1.16 to 57.09) and quinolones (OR: 3.51, 95% CI: 1.18 to 10.49). Similar findings were obtained for subgroup populations with diabetic foot infections (DFI). However, linezolid was significantly related to higher adverse events than ampicillin/sulbactam (OR: 3.25, 95% CI: 1.68 to 6.30) and cephalosporins (OR: 18.29, 95% CI: 1.59 to 209.76).

CONCLUSION

Linezolid appeared to be the most promising treatment regimen for staphylococcal bone and joint infections. However, due to the overall limited evidence, the research results need further high-quality RCTs for confirmation.

Evolutionary Trajectories toward High-Level β-Lactam/β-Lactamase Inhibitor Resistance in the Presence of Multiple β-Lactamases

β-Lactam antibiotics are the first choice for the treatment of most bacterial infections. However, the increased prevalence of β-lactamases, in particular extended-spectrum β-lactamases, in pathogenic bacteria has severely limited the possibility of using β-lactam treatments. Combining β-lactam antibiotics with β-lactamase inhibitors can restore treatment efficacy by negating the effect of the β-lactamase and has become increasingly important against infections caused by β-lactamase-producing strains. Not surprisingly, bacteria with resistance to even these combinations have been found in patients. Studies on the development of bacterial resistance to β-lactam/β-lactamase inhibitor combinations have focused mainly on the effects of single, chromosomal or plasmid-borne, β-lactamases. However, clinical isolates often carry more than one β-lactamase in addition to multiple other resistance genes. Here, we investigate how the evolutionary trajectories of the development of resistance to three commonly used β-lactam/β-lactamase inhibitor combinations, ampicillin-sulbactam, piperacillin-tazobactam, and ceftazidime-avibactam, were affected by the presence of three common β-lactamases, TEM-1, CTX-M-15, and OXA-1. First-step resistance was due mainly to extensive gene amplifications of one or several of the β-lactamase genes where the amplification pattern directly depended on the respective drug combination. Amplifications also served as a stepping-stone for high-level resistance in combination with additional mutations that reduced drug influx or mutations in the β-lactamase gene bla_CTX-M-15. This illustrates that the evolutionary trajectories of resistance to β-lactam/β-lactamase inhibitor combinations are strongly influenced by the frequent and transient nature of gene amplifications and how the presence of multiple β-lactamases shapes the evolution to higher-level resistance.

Can Intralesional Epidermal Growth Factor Reduce Skin Graft Applications in Patients with Diabetic Foot Ulcer?

BACKGROUND

Diabetic foot ulcer (DFU) is a serious health problem. Major amputation increases the risk of mortality in patients with DFU; therefore, treatment methods other than major amputation come to the fore for these patients. Graft applications create an appropriate environment for the reproduction of epithelial cells. Similarly, epidermal growth factor (EGF) also stimulates epithelization and increases epidermis formation. In this study, we aimed to compare patients with DFU treated with EGF and those treated with a split-thickness skin graft.

METHODS

Patients who were treated for DFU in the general surgery clinic were included in the study. The patients were evaluated retrospectively according to their demographic characteristics, wound characteristics, duration of treatment, and treatment modalities.

RESULTS

There were 26 patients in the EGF group and 21 patients in the graft group. The mean duration of treatment was 7 weeks (4-8 weeks) in the EGF group and 5.3 weeks (4-8 weeks) in the graft group (P < .05). In the EGF group, wound healing could not be achieved in one patient during the study period. In the graft group, no recovery was achieved in three patients (14.2%) in the donor site. Graft loss was detected in four patients (19%), and partial graft loss was observed in three patients (14.2%). The DFU of these patients were on the soles (85.7%). These patients have multiple comorbidities.

CONCLUSIONS

EGF application may be preferred to avoid graft complications in the graft area and the donor site, especially in elderly patients with multiple comorbidities and wounds on the soles.

Economic impact of diabetic foot ulcers on healthcare in Saudi Arabia: a retrospective study

BACKGROUND

Diabetic foot ulcers (DFU) are a critical complication of diabetes mellitus (DM) affecting life quality and significantly impacting healthcare resources.

OBJECTIVE

Determine the direct medical costs associated with treating DFU in King Fahad Hospital of the University and identify factors that could assist in developing resource management guidelines in Saudi Arabia.

DESIGN

Retrospective study.

SETTING

SETTING: King Fahad Hospital of the University, Al-Khobar, Saudi Arabia.

PATIENTS AND METHODS

The study included diabetic patients admitted with foot ulcerations between 2007 and 2017 inclusive. We determined management costs including drug usage, wound dressings, surgical procedures, admissions, and basic investigation.

MAIN OUTCOME MEASURES

Factors affecting the direct perspective medical costs of managing DFU.

SAMPLE SIZE

99 patients.

RESULTS

The overall cost of managing 99 patients with DFU was 6 618 043.3 SAR ($1 764 632.68 USD), which further translates to approximately 6684.9 SAR per patient/year ($1782.6 USD). The highest cost incurred was for admission expenditure (45.6%), followed by debridement (14.5%) and intensive care unit (ICU) admission (10.4%).

CONCLUSION

The overall healthcare expenditure in treating DFU is high, with hospital admissions and surgical procedures adding a significant increase to the total cost. Focused patient education on overall glycemic control and prevention of DFU may decrease complications and hence, the overall cost.

LIMITATIONS

Identified only the direct medical costs of DFU as the indirect costs were subjective and more difficult to quantify.

CONFLICT OF INTEREST

None.

Reactive oxygen species and uspA overexpession: an alternative bacterial response toward selection and maintenance of multidrug resistance in clinical isolates of uropathogenic E. coli

Emergence of multidrug resistance (MDR) in uropathogenic E. coli (UPEC) demands alternative therapeutic interventions. Bactericidal antibiotics at their sub-inhibitory concentration stimulate production of reactive oxygen species (ROS) that results in oxidative stress, generates mutations, and alters transcription of different genes. Sub-inhibitory concentration of antibiotics facilitates selection of highly resistant population. Universal stress protein A (uspA) overexpression in MDR-UPEC at sub-inhibitory bactericidal antibiotics concentration was investigated to explore alternative survival strategy against them. Fifty clinical UPEC isolates were screened. Minimum inhibitory concentration (MIC) against three different bactericidal antibiotics (ciprofloxacin, CIP; ceftazidime, CAZ; gentamycin, GEN) was determined by broth dilution method; ROS production by DCFDA and overexpression of uspA by real-time PCR were determined at the sub-inhibitory concentration of antibiotics. DNA ladder formation and SEM studies were performed with drug untreated and treated samples. Statistical analysis was done by Student's t test and Pearson's correlation analysis; 25 out of 50 UPEC exhibited high MIC against CIP (> 200 μg/ml), CAZ (> 500 μg/ml), GEN (> 500 μg/ml), with varied ROS production (p ≤ 0.001) in treated than untreated controls. DNA ladder formation confirmed ROS production in drug-treated samples. SEM analysis revealed unaltered cell morphology in both untreated and drug-treated bacteria. uspA was universally overexpressed in all 25 UPEC. A significant correlation (p ≤ 0.001) between ROS production and uspA overexpression was observed in 19 out of 25 MDR isolates at sub-inhibitory doses of the bactericidal antibiotics. Therefore, this study highlights an alternative strategy that the MDR isolates may acquire when exposed to sub-inhibitory drug concentration for their survival.

Economic evaluations considering costs and outcomes of diabetic foot ulcer infections: A systematic review

Background

Diabetic foot ulcer (DFU) is a severe complication of diabetes and particularly susceptible to infection. DFU infection intervention efficacy is declining due to antimicrobial resistance and a systematic review of economic evaluations considering their economic feasibility is timely and required.

Aim

To obtain and critically appraise all available full economic evaluations jointly considering costs and outcomes of infected DFUs.

Methods

A literature search was conducted across MedLine, CINAHL, Scopus and Cochrane Database seeking evaluations published from inception to 2019 using specific key concepts. Eligibility criteria were defined to guide study selection. Articles were identified by screening of titles and abstracts, followed by a full-text review before inclusion. We identified 352 papers that report economic analysis of the costs and outcomes of interventions aimed at diabetic foot ulcer infections. Key characteristics of eligible economic evaluations were extracted, and their quality assessed against the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist.

Results

542 records were screened and 39 full-texts assessed for eligibility. A total of 19 papers were included in the final analysis. All studies except one identified cost-saving or cost-effective interventions. The evaluations included in the final analysis were so heterogeneous that comparison of them was not possible. All studies were of “excellent”, “very good” or “good” quality when assessed against the CHEERS checklist.

Conclusions

Consistent identification of cost-effective and cost-saving interventions may help to reduce the DFU healthcare burden. Future research should involve clinical implementation of interventions with parallel economic evaluation rather than model-based evaluations.

Diabetes-associated infections: development of antimicrobial resistance and possible treatment strategies

Diabetes mellitus is associated with various types of infections notably skin, mucous membrane, soft tissue, urinary tract, respiratory tract and surgical and/or hospital-associated infections. The reason behind this frequent association with infections is an immunocompromised state of diabetic patient because uncontrolled hyperglycemia impairs overall immunity of diabetic patient via involvement of various mechanistic pathways that lead to the diabetic patient as immunocompromised. There are specific microbes that are associated with each type of infection and their presence indicates specific type of infections. For instance, E. coli and Klebsiella are the most common causative pathogens responsible for the development of urinary tract infections. Diabetic-foot infections commonly occur in diabetic patients. In this article, we have mainly focused on the association of diabetes mellitus with various types of bacterial infections and the pattern of resistance against antimicrobial agents that are frequently used for the treatment of diabetes-associated infections. Moreover, we have also summarized the possible treatment strategies against diabetes-associated infections.

Thinking Outside the Bug: Molecular Targets and Strategies to Overcome Antibiotic Resistance

Since their discovery in the early 20th century, antibiotics have been used as the primary weapon against bacterial infections. Due to their prophylactic effect, they are also used as part of the cocktail of drugs given to treat complex diseases such as cancer or during surgery, in order to prevent infection. This has resulted in a decrease of mortality from infectious diseases and an increase in life expectancy in the last 100 years. However, as a consequence of administering antibiotics broadly to the population and sometimes misusing them, antibiotic-resistant bacteria have appeared. The emergence of resistant strains is a global health threat to humanity. Highly-resistant bacteria like Staphylococcus aureus (methicillin-resistant) or Enterococcus faecium (vancomycin-resistant) have led to complications in intensive care units, increasing medical costs and putting patient lives at risk. The appearance of these resistant strains together with the difficulty in finding new antimicrobials has alarmed the scientific community. Most of the strategies currently employed to develop new antibiotics point towards novel approaches for drug design based on prodrugs or rational design of new molecules. However, targeting crucial bacterial processes by these means will keep creating evolutionary pressure towards drug resistance. In this review, we discuss antibiotic resistance and new options for antibiotic discovery, focusing in particular on new alternatives aiming to disarm the bacteria or empower the host to avoid disease onset.

Systemic antibiotics for treating diabetic foot infections

BACKGROUND

Foot infection is the most common cause of non-traumatic amputation in people with diabetes. Most diabetic foot infections (DFIs) require systemic antibiotic therapy and the initial choice is usually empirical. Although there are many antibiotics available, uncertainty exists about which is the best for treating DFIs.

OBJECTIVES

To determine the effects and safety of systemic antibiotics in the treatment of DFIs compared with other systemic antibiotics, topical foot care or placebo.

SEARCH METHODS

In April 2015 we searched the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library); Ovid MEDLINE, Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE, and EBSCO CINAHL. We also searched in the Database of Abstracts of Reviews of Effects (DARE; The Cochrane Library), the Health Technology Assessment database (HTA; The Cochrane Library), the National Health Service Economic Evaluation Database (NHS-EED; The Cochrane Library), unpublished literature in OpenSIGLE and ProQuest Dissertations and on-going trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating the effects of systemic antibiotics (oral or parenteral) in people with a DFI. Primary outcomes were clinical resolution of the infection, time to its resolution, complications and adverse effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed the risk of bias, and extracted data. Risk ratios (RR) were estimated for dichotomous data and, when sufficient numbers of comparable trials were available, trials were pooled in a meta-analysis.

MAIN RESULTS

We included 20 trials with 3791 participants. Studies were heterogenous in study design, population, antibiotic regimens, and outcomes. We grouped the sixteen different antibiotic agents studied into six categories: 1) anti-pseudomonal penicillins (three trials); 2) broad-spectrum penicillins (one trial); 3) cephalosporins (two trials); 4) carbapenems (four trials); 5) fluoroquinolones (six trials); 6) other antibiotics (four trials).Only 9 of the 20 trials protected against detection bias with blinded outcome assessment. Only one-third of the trials provided enough information to enable a judgement about whether the randomisation sequence was adequately concealed. Eighteen out of 20 trials received funding from pharmaceutical industry-sponsors.The included studies reported the following findings for clinical resolution of infection: there is evidence from one large trial at low risk of bias that patients receiving ertapenem with or without vancomycin are more likely to have resolution of their foot infection than those receiving tigecycline (RR 0.92, 95% confidence interval (CI) 0.85 to 0.99; 955 participants). It is unclear if there is a difference in rates of clinical resolution of infection between: 1) two alternative anti-pseudomonal penicillins (one trial); 2) an anti-pseudomonal penicillin and a broad-spectrum penicillin (one trial) or a carbapenem (one trial); 3) a broad-spectrum penicillin and a second-generation cephalosporin (one trial); 4) cephalosporins and other beta-lactam antibiotics (two trials); 5) carbapenems and anti-pseudomonal penicillins or broad-spectrum penicillins (four trials); 6) fluoroquinolones and anti-pseudomonal penicillins (four trials) or broad-spectrum penicillins (two trials); 7) daptomycin and vancomycin (one trial); 8) linezolid and a combination of aminopenicillins and beta-lactamase inhibitors (one trial); and 9) clindamycin and cephalexin (one trial).Carbapenems combined with anti-pseudomonal agents produced fewer adverse effects than anti-pseudomonal penicillins (RR 0.27, 95% CI 0.09 to 0.84; 1 trial). An additional trial did not find significant differences in the rate of adverse events between a carbapenem alone and an anti-pseudomonal penicillin, but the rate of diarrhoea was lower for participants treated with a carbapenem (RR 0.58, 95% CI 0.36 to 0.93; 1 trial). Daptomycin produced fewer adverse effects than vancomycin or other semi-synthetic penicillins (RR 0.61, 95%CI 0.39 to 0.94; 1 trial). Linezolid produced more adverse effects than ampicillin-sulbactam (RR 2.66; 95% CI 1.49 to 4.73; 1 trial), as did tigecycline compared to ertapenem with or without vancomycin (RR 1.47, 95% CI 1.34 to 1.60; 1 trial). There was no evidence of a difference in safety for the other comparisons.

AUTHORS' CONCLUSIONS

The evidence for the relative effects of different systemic antibiotics for the treatment of foot infections in diabetes is very heterogeneous and generally at unclear or high risk of bias. Consequently it is not clear if any one systemic antibiotic treatment is better than others in resolving infection or in terms of safety. One non-inferiority trial suggested that ertapenem with or without vancomycin is more effective in achieving clinical resolution of infection than tigecycline. Otherwise the relative effects of different antibiotics are unclear. The quality of the evidence is low due to limitations in the design of the included trials and important differences between them in terms of the diversity of antibiotics assessed, duration of treatments, and time points at which outcomes were assessed. Any further studies in this area should have a blinded assessment of outcomes, use standardised criteria to classify severity of infection, define clear outcome measures, and establish the duration of treatment.

A systematic review of cost-effectiveness analyses of complex wound interventions reveals optimal treatments for specific wound types

BACKGROUND

Complex wounds present a substantial economic burden on healthcare systems, costing billions of dollars annually in North America alone. The prevalence of complex wounds is a significant patient and societal healthcare concern and cost-effective wound care management remains unclear. This article summarizes the cost-effectiveness of interventions for complex wound care through a systematic review of the evidence base.

METHODS

We searched multiple databases (MEDLINE, EMBASE, Cochrane Library) for cost-effectiveness studies that examined adults treated for complex wounds. Two reviewers independently screened the literature, abstracted data from full-text articles, and assessed methodological quality using the Drummond 10-item methodological quality tool. Incremental cost-effectiveness ratios were reported, or, if not reported, calculated and converted to United States Dollars for the year 2013.

RESULTS

Overall, 59 cost-effectiveness analyses were included; 71% (42 out of 59) of the included studies scored 8 or more points on the Drummond 10-item checklist tool. Based on these, 22 interventions were found to be more effective and less costly (i.e., dominant) compared to the study comparators: 9 for diabetic ulcers, 8 for venous ulcers, 3 for pressure ulcers, 1 for mixed venous and venous/arterial ulcers, and 1 for mixed complex wound types.

CONCLUSIONS

Our results can be used by decision-makers in maximizing the deployment of clinically effective and resource efficient wound care interventions. Our analysis also highlights specific treatments that are not cost-effective, thereby indicating areas of resource savings. Please see related article: http://dx.doi.org/10.1186/s12916-015-0288-5.

Diabetic foot infections: current concept review

The purpose of this manuscript is to provide a current concept review on the diagnosis and management of diabetic foot infections which are among the most serious and frequent complications encountered in patients with diabetes mellitus. A literature review on diabetic foot infections with emphasis on pathophysiology, identifiable risk factors, evaluation including physical examination, laboratory values, treatment strategies and assessing the severity of infection has been performed in detail. Diabetic foot infections are associated with high morbidity and risk factors for failure of treatment and classification systems are also described. Most diabetic foot infections begin with a wound and once an infection occurs, the risk of hospitalization and amputation increases dramatically. Early identification of infection and prompt treatment may optimize the patient's outcome and provide limb salvage.

Expert opinion on the management of infections in the diabetic foot

This update of the International Working Group on the Diabetic Foot incorporates some information from a related review of diabetic foot osteomyelitis (DFO) and a systematic review of the management of infection of the diabetic foot. The pathophysiology of these infections is now well understood, and there is a validated system for classifying the severity of infections based on their clinical findings. Diagnosing osteomyelitis remains difficult, but several recent publications have clarified the role of clinical, laboratory and imaging tests. Magnetic resonance imaging has emerged as the most accurate means of diagnosing bone infection, but bone biopsy for culture and histopathology remains the criterion standard. Determining the organisms responsible for a diabetic foot infection via culture of appropriately collected tissue specimens enables clinicians to make optimal antibiotic choices based on culture and sensitivity results. In addition to culture-directed antibiotic therapy, most infections require some surgical intervention, ranging from minor debridement to major resection, amputation or revascularization. Clinicians must also provide proper wound care to ensure healing of the wound. Various adjunctive therapies may benefit some patients, but the data supporting them are weak. If properly treated, most diabetic foot infections can be cured. Providers practising in developing countries, and their patients, face especially challenging situations.

Current challenges in the management of the infected patient

PURPOSE OF REVIEW

Management of hospital-associated infections (HAIs) has been made more challenging by the increasing proportion of immunocompromised or otherwise severely ill patients and increasing prevalence of antibiotic-resistant pathogens in this environment. This review examines strategies to optimize clinical outcomes and lower healthcare costs for patients with HAIs by focusing on patient-related, pathogen-related, and drug-related factors.

RECENT FINDINGS

Factors have converged to increase the risk of infection with antibiotic-resistant pathogens in the current hospital environment, including the increasing prevalence of resistant species and number of hospitalized patients with conditions increasingly susceptible to infection with drug-resistant bacteria. Although the list of bacterial pathogens associated with HAIs has been fairly constant over time, the prevalence and resistance profile of these individual species continues to evolve. Periodic antibiograms should be utilized to access local patterns of resistance within the different hospital wards. Outcomes for patients with HAIs are optimized with early empiric treatment with an appropriate regimen, selected on the basis of patient characteristics and local resistance patterns. Dosing strategies should be utilized to ensure that the efficacy of an appropriate antibiotic is optimized, by achieving the pharmacodynamic target predictive of its efficacy. Using these strategies improves quality of care and is associated with lower overall healthcare costs.

SUMMARY

Bacterial resistance is an increasing problem in the hospital environment, and has been associated with poorer clinical outcomes and elevated healthcare costs. By using patient characteristics, local antibiograms, and dosing strategies to achieve an optimal pharmacodynamic profile, early appropriate empiric therapy can be utilized to improve clinical outcomes, minimize the development of resistance, and reduce healthcare costs.

Length of stay and hospital costs associated with a pharmacodynamic-based clinical pathway for empiric antibiotic choice for ventilator-associated pneumonia

STUDY OBJECTIVE

To determine hospital costs associated with the use of a clinical pathway implemented in our intensive care units (ICUs) to optimize antibiotic regimen selection for patients with ventilator-associated pneumonia (VAP) compared with costs in a historical control group treated according to prescriber preference.

DESIGN

Retrospective cost analysis from the hospital perspective.

SETTING

Single, tertiary-care medical center.

PATIENTS

One hundred sixty-six adults with VAP from the medical, surgical, and neurotrauma ICUs (73 historical control patients [2004-2005] and 93 patients given an empiric antibiotic clinical pathway for VAP [2006-2007]).

MEASUREMENTS AND MAIN RESULTS

The VAP clinical pathway consisted of an ICU-specific three-drug regimen that considered local minimum inhibitory concentration distributions and a pharmacodynamically optimized dosing strategy. Hospital cost data were collected and inflated to 2007 according to the consumer price index. The VAP-related length of treatment, hospitalization costs, and antibiotic costs were compared between groups. The median VAP length of treatment was 24 days (interquartile range [IQR] 13-35 days] and 11 days (IQR 7-17 days) for historical and clinical pathway groups, respectively (p<0.001). Daily hospital costs were similar for both cohorts over the first 7 days, after which costs declined significantly for patients treated with the clinical pathway (p<0.001). When controlling for baseline differences between groups and length of stay before development of VAP, patients treated with the clinical pathway had shorter lengths of ICU stay after VAP, shorter total hospital lengths of stay after VAP, and lower hospital costs after the treatment of VAP. Median total antibiotic costs for individual patients were similar between groups ($535 [IQR $261-998] vs $482 [IQR $222-985] clinical pathway vs control, p=0.45), and the proportion of VAP hospital resources consumed by antibiotics for both groups was low.

CONCLUSION

Although aggressive dosing of more costly antibiotics was empirically prescribed using the clinical pathway, patients in this group exhibited a shorter duration of treatment, reduced hospital length of stay after VAP, and lower hospital costs without any significant increase in antibiotic expenditures.

Management and prevention of diabetic foot ulcers and infections: a health economic review

Diabetic foot ulcers and infections are common and incur substantial economic burden for society, patients and families. We performed a comprehensive review, on a number of databases, of health economic evaluations of a variety of different prevention, diagnostic and treatment strategies in the area of diabetic foot ulcers and infections. We included English-language, peer-reviewed, cost-effectiveness, cost-minimization, cost-utility and cost-benefit studies that evaluated a treatment modality against placebo or comparator (i.e. drug, standard of care), regardless of year. Differences were settled through consensus. The search resulted in 1885 potential citations, of which 20 studies were retained for analysis (3 cost minimization, 13 cost effectiveness and 4 cost utility). Quality scores of studies ranged from 70.8% (fair) to 87.5% (good); mean = 78.4% +/- 5.33%.In diagnosing osteomyelitis in patients with diabetic foot infection, magnetic resonance imaging (MRI) showed 82% sensitivity and 80% specificity. MRI cost less than 3-phase bone scanning + Indium (In)-111/Gallium (Ga)-67; however, when compared with prolonged antibacterials, MRI cost $US120 (year 1993 value) more without additional quality-adjusted life-expectancy. Prevention strategies improved life expectancy and QALYs and reduced foot ulcer rates and amputations.Ampicillin/sulbactam and imipenem/cilastatin were both 80% successful in treating diabetic foot infections but the latter cost $US2924 more (year 1994 value). Linezolid cure rates were higher (97.7%) than vancomycin (86.0%) and cost $US873 less (year 2004 value). Ertapenem costs were significantly lower than piperacillin/tazobactam ($US356 vs $US503, respectively; year 2005 values). Becaplermin plus good wound care may be cost effective in specific populations. Bioengineered living-skin equivalents increased ulcer-free months and ulcers healed, but costs varied between countries. Promogran produced more ulcer-free months than wound care alone (3.75 vs 3.41 months, respectively). Treatment with cadexomer iodine resulted in higher rates of healed ulcer (29% vs 11%) and lower weekly treatment costs (Swedish krona [SEK]903 vs SEK1421; year 1993 values) than standard care. Filgrastim decreased hospital stays, time to resolution and costs (36% lower) compared with usual care. Adjunctive hyperbaric oxygen produced an incremental cost per QALY at year 1 of $US27 310 and $US2255 at year 12 (year 2001 values).Overall, preventive strategies were shown to be cost effective and potentially cost saving. Various antibacterial regimens are cost effective but empiric choices should be based on local resistance patterns. MRI was cost effective compared with three-phase bone scanning + In-111/Ga-67 but not against prolonged antibacterial therapy. Other innovations (becaplermin, bioengineered living-skin equivalents, filgrastim, cadexomer iodine ointment, hyperbaric oxygen, Promogran may be cost effective in this population but more studies are needed to confirm these findings.

Cost-effectiveness of oral gemifloxacin versus intravenous ceftriaxone followed by oral cefuroxime with/without a macrolide for the treatment of hospitalized patients with community-acquired pneumonia

We studied the cost-effectiveness of oral gemifloxacin with intravenous ceftriaxone followed by oral cefuroxime with or without a macrolide to treat patients hospitalized with community-acquired pneumonia. Data were prospectively collected as part of a randomized multicenter study. The costs evaluated included antimicrobial acquisition (1st level); plus preparation, dispensing, and administration costs, and treatment of antimicrobial-related adverse events and clinical failures (2nd level); plus per diem costs for hospital stay related to study drug administration (3rd level). At follow-up, clinical success was similar between gemifloxacin (76.9%)- and ceftriaxone (79.1%)-treated patients. The median 1st-level costs for gemifloxacin and ceftriaxone were $136 and $470 (P<0.001), respectively. For the 2nd level, these costs were $158 and $542 (P<0.001), and for the 3rd level, these were $5052 and $5789 (P=0.025), respectively. The median cost per expected success was $6568 for gemifloxacin and $7321 for ceftriaxone (P=0.29). Oral gemifloxacin is clinically effective and has an economic advantage over ceftriaxone, followed by oral cefuroxime with or without a macrolide.

Comparative costs of ertapenem and piperacillin–tazobactam in the treatment of diabetic foot infections

PURPOSE

To evaluate potential cost savings, trial data were used to determine the clinical outcomes for i.v. ertapenem given once daily and i.v. piperacillin-tazobactam given every six hours daily in treating diabetic foot infections.

METHODS

A cost-minimization analysis (CMA) was conducted on the drug-dosing data of the subset of patients enrolled in a recent double-blind randomized trial who were treated solely as inpatients and were clinically evaluable at fi nal assessment (n = 99). Cost per dose was calculated from (a) average hospital acquisition price per dose for ertapenem ($40.52) or piperacillin-tazobactam ($13.58), (b) average U.S. wages and benefits for labor, based on nine published time-and-motion studies of i.v. antibiotic preparation and administration ($3.10), and (c) consumable supplies, using a 40% discount off the manufacturer list price ($2.90). For each patient, the actual number of antibiotic doses given was multiplied by total cost per dose.

RESULTS

There were no significant differences between antibiotic groups with respect to patient demographics, percentage with a severe wound, and mean days of i.v. therapy. Compared with piperacillin-tazobactam, patients treated with ertapenem received significantly fewer mean doses (25.5 versus 7.5; p < 0.0001) and lower antibiotic-related costs ($502.76 versus $355.55, respectively; p < 0.001). The $147.21 difference between groups accounts for approximately 3% of total hospital Medicare reimbursements for these infections.

CONCLUSION

A CMA of treatment of diabetic foot infections showed that, compared with piperacillin-tazobactam given four times daily i.v., ertapenem given once daily i.v. was associated with lower drug acquisition and supply costs and less time and labor devoted to preparation and administration of i.v. therapy.

Direct costs in patients hospitalised with community-acquired pneumonia after non-response to outpatient treatment with macrolide antibacterials in the US

INTRODUCTION

Antibacterial cost-containment programmes emphasise the use of narrow-spectrum generic agents whenever possible. The use of these agents is driven by their lower purchase prices; the consequences of treatment failure are rarely considered. This study was conducted to identify the costs of treating patients hospitalised with community-acquired pneumonia (CAP) associated with Streptococcus pneumoniae following failure to respond to outpatient treatment with macrolide antibacterials.

METHODS

A multicentre, retrospective, observational study was performed in patients with CAP due to S. pneumoniae who were admitted to 31 North American hospitals following a lack of response to >or=2 days of outpatient treatment with a macrolide antibacterial. Direct medical costs (year 2004 values) of infection-related hospital resources, including antibacterials (purchase, preparation, dispensing, administration and monitoring), diagnostic tests, therapeutic procedures, treatment of adverse events and therapeutic failures, and hospitalisation per diem (ward, critical care and ventilator days), were analysed. Total hospital costs were then compared with standard diagnosis-related group (DRG) reimbursement.

RESULTS

A total of 122 patients were enrolled. Patients were frequently bacteraemic (52%) and infected with macrolide-resistant strains of S. pneumoniae (71%). Initial inpatient antibacterial treatment was not successful in 17 patients (14%) and seven patients (5.7%) died. The mean length of stay was 8.7 days (SD 7) including 1.3 days (SD 2.9) in a critical care unit and 1.4 days (SD 4.4) of mechanical ventilation. The mean cost of hospitalisation was US dollars 12,678 (SD 13 346) but standard DRG reimbursement averaged only US dollars 8,634.

CONCLUSIONS

Patients who do not respond to outpatient treatment with a macrolide antibacterial and who are subsequently hospitalised with CAP caused by S. pneumoniae are likely to be infected with a non-susceptible strain, are frequently bacteraemic, are at an increased risk for mortality compared with previously published estimates in patients with CAP due to S. pneumoniae, and incur hospital costs that far exceed standard DRG reimbursement for CAP.

Ampicillin/Sulbactam

Ampicillin/sulbactam is a beta-lactam/beta-lactamase inhibitor combination with a broad spectrum of antibacterial activity against Gram-positive, Gram-negative and anaerobic bacteria. Data from comparative studies justify the use of ampicillin/sulbactam in a 2 : 1 ratio in various severe bacterial infections. In comparative clinical trials, ampicillin/sulbactam has proved to be a significant drug in the therapeutic armamentarium for lower respiratory tract infections and aspiration pneumonia, gynaecological/obstetrical infections, intra-abdominal infections, paediatric infections such as acute epiglottitis and periorbital cellulitis, diabetic foot infections, and skin and soft tissue infections. Of particular interest during this era of increasing antimicrobial resistance in various settings and populations is the effectiveness of sulbactam against a considerable proportion of infections due to Acinetobacter baumannii.

Systematic review of antimicrobial treatments for diabetic foot ulcers

BACKGROUND

Foot ulcers in diabetes are associated with increased mortality, illness and reduced quality of life. Ulcer infection impairs healing and antimicrobial interventions may cure infection, aid healing and reduce amputation rates.

OBJECTIVES

To systematically review the evidence for antimicrobial interventions for foot ulcers in diabetes.

METHODS

We searched 16 databases, 11 Internet sites, three books, conference proceedings, a journal and bibliographies in November 2002. We included randomized controlled trials (RCTs) or controlled clinical trials (CCTs).

RESULTS

Twenty-three studies investigated the effectiveness or cost-effectiveness of antimicrobial agents: intravenous antibiotics (n = 8); oral antibiotics (n = 5); topical antimicrobials (n = 4); subcutaneous granulocyte-colony stimulating factor (G-CSF) (n = 4); Ayurvedic preparations (n = 1): and sugar vs. antibiotics vs. standard care (n = 1). The trials were small and too dissimilar to be pooled. There is no strong evidence for any particular antimicrobial agent for the prevention of amputation, resolution of infection, or ulcer healing. Pexiganan cream may be as effective as oral ofloxacin for resolution of infection. Ampicillin and sulbactam cost less than imipenem/cilastatin, G-CSF cost less than standard care and cadexomer iodine dressings may cost less than daily dressings.

CONCLUSIONS

The evidence is too weak to recommend any particular antimicrobial agent. Large studies are needed of the effectiveness and cost-effectiveness of antimicrobial interventions.

A systematic approach to diabetic foot infections

Foot infection is the most common reason for hospitalization and subsequent lower extremity amputation among persons with diabetes. Foot ulceration caused by diabetic neuropathy, trauma, and peripheral vascular disease can lead to a limbor life-threatening infection. The optimum treatment of these potentially devastating conditions depends on a multidisciplinary approach that addresses the related or underlying disorders and thus ensures proper wound healing and a positive outcome. In addition to antibiotic therapy, severe soft-tissue or bone infections may necessitate surgical treatment, including drainage, débridement, and vascular reconstruction. Initial (empiric) antibiotic therapy should provide coverage against staphylococci and streptococci and should be revised according culture results. Antibiotic therapy is not indicated in clinically noninfected wounds. The duration of antibiotic treatment can range from 1 week for mild infections to 6 weeks or more for residual osteomyelitis and severe deep tissue infections. Aggressive (and sometimes repeated or staged) surgical intervention and appropriate antibiotic therapy can reduce the likelihood of a major amputation and the duration of hospitalization.

Economics of antibiotic use policies

Today more than ever, hospitals must effectively manage the use of antibiotics to control costs and preserve their usefulness. To achieve this goal, antibiotic management must evolve from overly simplistic antibiotic cost containment to more complex, multidisciplinary, appropriate use programs that are founded on clinical outcomes-based pharmacoeconomic analyses. This article addresses common cost-containment activities as they relate to antibiotics and examines their consequences. Examples of successful antimicrobial stewardship and the role of pharmacoeconomic analyses also are provided. Cost-effectiveness studies of cefepime are presented to illustrate the utility of these analyses and provide information that can form the basis for decisions regarding placement of cefepime on hospital formularies.

Diagnosis and treatment of diabetic foot infections

Diabetic foot infections frequently cause morbidity, hospitalization, and amputations. Gram-positive cocci, especially staphylococci and also streptococci, are the predominant pathogens. Chronic or previously treated wounds often yield several microbes on culture, including gram-negative bacilli and anaerobes. Optimal culture specimens are wound tissue taken after debridement. Infection of a wound is defined clinically by the presence of purulent discharge or inflammation; systemic signs and symptoms are often lacking. Only infected wounds require antibiotic therapy, and the agents, route, and duration are predicated on the severity of infection. Mild to moderate infections can usually be treated in the outpatient setting with oral agents; severe infections require hospitalization and parenteral therapy. Empirical therapy must cover gram-positive cocci and should be broad spectrum for severe infections. Definitive therapy depends on culture results and the clinical response. Bone infection is particularly difficult to treat and often requires surgery. Several adjuvant agents may be beneficial in some cases.

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.

Clinical role of beta-lactam/beta-lactamase inhibitor combinations

The use of beta-lactamase inhibitors in combination with beta-lactam antibiotics is currently the most successful strategy to combat a specific resistance mechanism. Their broad spectrum of activity originates from the ability of respective inhibitors to inactivate a wide range of beta-lactamases produced by Gram-positive, Gram-negative, anaerobic and even acid-fast pathogens. Clinical experience confirms their effectiveness in the empirical treatment of respiratory, intra-abdominal, and skin and soft tissue infections. There is evidence to suggest that they are efficacious in treating patients with neutropenic fever and nosocomial infections, especially in combination with other agents. beta-Lactam/beta-lactamase inhibitor combinations are particularly useful against mixed infections. Their role in treating various multi-resistant pathogens such as Acinetobacter species and Stenotrophomonas maltophilia are gaining importance. Although, generally, they do not constitute reliable therapy against extended-spectrum beta-lactamase producers, their substitution in place of cephalosporins appears to reduce emergence of the latter pathogens. Similarly, their use may also curtail the emergence of other resistant pathogens such as Clostridium difficile and vancomycin-resistant enterococci. beta-Lactam/beta-lactamase inhibitor combinations are generally well tolerated and their oral forms provide effective outpatient therapy against many commonly encountered infections. In certain scenarios, they could even be more cost-effective than conventional combination therapies. With the accumulation of so much clinical experience, their role in the management of infections is now becoming more clearly defined.

Cost-effectiveness of IV-to-oral switch therapy: azithromycin vs cefuroxime with or without erythromycin for the treatment of community-acquired pneumonia

STUDY OBJECTIVE

To conduct a cost-effectiveness analysis of IV-to-oral regimens of azithromycin vs cefuroxime with or without erythromycin in the treatment of patients hospitalized with community-acquired pneumonia (CAP).

PATIENTS

Of the 268 evaluable patients enrolled into a randomized, multicenter clinical trial of adults, 266 patients had sufficient data to be included in this cost-effectiveness analysis. One hundred thirty-six patients received azithromycin, and 130 patients received cefuroxime with or without erythromycin.

METHODS

A pharmacoeconomic analysis from the hospital provider perspective was conducted. Health-care resource utilization was extracted from the clinical database and converted to national reference costs. Decision analysis was used to structure and characterize outcomes. Sensitivity analyses were performed, and statistics were applied to the cost-effectiveness ratios.

RESULTS

The clinical success and adverse event rates and antibiotic-related length of stay were 78%, 11.8%, and 5.8 days for the azithromycin group and 75%, 20.7%, and 6.4 days for the group receiving cefuroxime with or without erythromycin, respectively. Geometric mean treatment costs were 4,104 US dollars (95% confidence interval [CI], 3,874 to 4,334 US dollars) for the azithromycin group, and 4,578 US dollars (95% CI, 4,319 to 4,837 US dollars) for the group receiving cefuroxime with or without erythromycin (p = 0.06). The cost-effectiveness ratios were 5,265 US dollars per expected cure for the azithromycin group, and 6,145 US dollars per expected cure for group receiving cefuroxime with or without erythromycin (p = 0.05).

CONCLUSIONS

Despite a higher per-dose purchase price, overall costs with azithromycin tended to be lower due to decreased duration of therapy, lower preparation and administration costs, and reduced hospital length of stay. As empiric therapy, azithromycin monotherapy was cost-effective compared to cefuroxime with or without erythromycin for patients hospitalized with CAP who have no underlying cardiopulmonary disease, and no risk factors for either drug-resistant pneumococci or enteric Gram-negative pathogens.

Cost-effectiveness of Gatifloxacin vs Ceftriaxone With a Macrolide for the Treatment of Community-Acquired Pneumonia

STUDY OBJECTIVE

To determine the cost-effectiveness of sequential IV to oral gatifloxacin therapy vs IV ceftriaxone with or without IV erythromycin to oral clarithromycin therapy to treat community-acquired pneumonia (CAP) patients requiring hospitalization.

PATIENTS

Two hundred eighty-three patients enrolled in a randomized, double-blind, clinical trial were eligible for inclusion in the cost-effectiveness analysis.

METHODS

Data collected included patient demographics, clinical and microbiological outcomes, length of stay (LOS), and antibiotic-related LOS (LOSAR). Costs evaluated include drug acquisition (level 1); plus costs of preparation, dispensing, and administration, treating adverse events, and clinical failures (level 2); plus hospital per diem costs (level 3). Robustness of economic findings was tested using sensitivity analyses.

RESULTS

Two hundred three patients were clinically and economically evaluable (98 receiving gatifloxacin and 105 receiving ceftriaxone). IV erythromycin was administered to 35 patients in the ceftriaxone-treated group. Oral conversion was achieved in 98% of patients in each group. Clinical cure and microbiological eradication rates did not differ statistically (98% and 97% with gatifloxacin vs 92% and 92% with ceftriaxone, respectively). Overall, neither geometric mean LOS nor LOSAR differed significantly (4.2 days and 4.1 days with gatifloxacin vs 4.9 days and 4.9 days with ceftriaxone, respectively). Treatment failures in the ceftriaxone group contributed to a mean incremental increase in LOSAR of 1.09 days and increased mean cost per patient. The geometric mean costs per patient (level 3) were $5,109 for gatifloxacin and $6,164 for ceftriaxone (p = 0.011). The cost-effectiveness ratios (mean cost per expected success) were $5,236:1 and $7,047:1 for gatifloxacin and ceftriaxone, respectively.

CONCLUSIONS

Gatifloxacin monotherapy for CAP patients requiring hospitalization is clinically effective and provides an economic advantage compared to the regimen of ceftriaxone with or without erythromycin IV with a switch to oral clarithromycin.

Cost effectiveness of cephalosporin monotherapy and aminoglycoside/ureidopenicillin combination therapy. For the treatment of febrile episodes in neutropenic patients

OBJECTIVE

To assess the relative cost effectiveness of cephalosporin monotherapy options and aminoglycoside/ureidopenicillin combination therapy for the treatment of febrile episodes in adult patients with neutropenia.

DESIGN AND SETTING

This was a retrospective cost-effectiveness analysis conducted from the institutional perspective.

METHODS

The analysis was based on 741 febrile episodes in adult patients with neutropenia enrolled in 5 randomised trials: 3 comparing monotherapy with ceftazidime or cefepime, and 2 comparing cefepime monotherapy versus aminoglycoside/ureidopenicillin combination therapy. Resource utilisation included costs for study antibacterials, treatment of adverse effects and failures, and hospitalisation. The primary end-point was the overall cost of treatment per patient. Cost-effectiveness ratios were also analysed.

RESULTS

No significant differences in clinical success rates were detected. Median per-patient costs in the monotherapy comparisons were $US7849 for cefepime and $US7788 for ceftazidime [1997 values; not significantly different (NS)]. Corresponding costs for the monotherapy versus combination therapy comparisons were $US9780 for cefepime and $US10 159 for gentamicin/ureidopenicillin (NS). Despite a higher acquisition cost for cefepime, there were no statistically significant differences in cost effectiveness compared with either ceftazidime monotherapy or gentamicin/ureidopenicillin combination therapy. Sensitivity analyses revealed that monotherapy can be cost effective compared with combination therapy in many situations.

CONCLUSION

There were no economic differences between the 3 regimens tested. Therefore drug cost should not be a deciding factor when choosing antibacterial therapy for the treatment of febrile episodes in adult patients with neutropenia.

Pharmacotherapy of lower limb diabetic ulcers

OBJECTIVE

To discuss the pathophysiology, microbiology, and pharmacotherapy of lower extremity (LE) diabetic ulcers.

DATA SOURCES

A MEDLINE search from 1966 to April 1999 was conducted. The search was limited to humans and English-language journals. Key search words included "diabetic ulcer," "fluoroquinolones," "beta-lactam," "hyperbaric oxygen," "diabetes mellitus," "diabetic foot," and "growth factor."

STUDY SELECTION

Randomized and nonrandomized studies were selected for review. Results of randomized, placebo-controlled studies were emphasized more than nonrandomized results.

DATA SYNTHESIS

LE ulcers are a common cause of hospitalization, and cause significant morbidity and mortality. Staphylococcus aureus is the most common pathogen in non-limb-threatening infections; Gram-negative bacteria and anaerobes are most prevalent in limb-threatening and life-threatening infections. Oral antibiotic therapy may be used in non-limb-threatening infections, if adequate response is achieved in 24-48 hours; otherwise, intravenous antibiotics should be started. Intravenous antibiotics should be the initial therapy for limb-threatening or life- threatening ulcers. Antimicrobial therapy of at least 10-14 days has been effective in treating LE ulcers in the absence of osteomyelitis. Growth factors offer another treatment alternative, although only becaplermin is currently approved for diabetic ulcers.

CONCLUSION

Antibiotic therapy has been effective for the treatment of LE diabetic ulcers. However, further studies are required to identify optimal antibiotics and dosage regimens. Growth factors may have a role but additional research is needed to determine when best to initiate this therapy.

Success rates and cost-effectiveness of antibiotic combinations for initial treatment of central-venous-line infections during total parenteral nutrition

BACKGROUND

Central-venous-line infections can be successfully treated with appropriate antibiotics, thus avoiding the need for catheter removal. Based on our experience, vancomycin, gentamicin, piperacillin, ceftazidime, and amphotericin, alone or in combination, are usually administered, pending sensitivity results. This empirical list, however, has never been verified against actual sensitivity results nor has it been tested for cost or efficacy.

METHODS

Medical records of inpatients on hyperalimentation over 1 year were reviewed. Success rate, therapy duration, and drug acquisition cost and charge were assessed for central-venous-line infections. Antibiotics then were paired and evaluated in terms of charge and efficacy against all microorganisms as determined by sensitivity results.

RESULTS

In 500 inpatients receiving hyperalimentation for 9,698 patient-days, 8.4 central-venous-line infections/1,000 patient-days occurred. Staphylococcus non-aureus, Candida species, Enterococcus faecium, and Staphylococcus aureus predominantly were isolated. Of the infections, 51 (67%) were sensitive to one or more of the initial antibiotics. A 2-week course of antibiotics successfully treated 50 (66%) catheter infections without line removal. Appropriate initial therapy on average reduced treatment duration by 8 to 10 days and drug charges by $400 to $700.

CONCLUSIONS

Amikacin-vancomycin appears to be the most cost-effective selection for presumed central-venous-line infections, pending sensitivity results, followed by valid alternatives. Lower failure rates are well worth the extra cost in pharmaceutical charges.

Evidence-based antibiotic therapy of diabetic foot infections

In addition to proper cleansing, debridement and local wound care, foot infections in diabetic patients require carefully selected antibiotic therapy. Serious infections necessitate hospitalization for initial parenteral broad-spectrum antibiotic therapy. Appropriately selected patients with mild infections can be treated as outpatients with oral (or even topical) therapy. Initial antibiotic selection is usually empirical, but definitive therapy may be modified based on culture results and the clinical response. Therapy should nearly always be active against staphylococci and streptococci, with broader-spectrum agents indicated if Gram-negative or anaerobic organisms are likely. In infected foot tissues levels of most antibiotics, except fluoroquinolones, are often subtherapeutic. The duration of therapy ranges from a week (for mild soft tissue infections) to over 6 weeks (for osteomyelitis). Recent antibiotic trials have shown that several intravenously or orally administered agents are effective in treating these infections, with no one agent or combination emerging as optimal. Suggested regimens based on the severity of infection are provided.

A Current Approach to Diabetic Foot Infections

Foot infections are a common, complex, and serious problem in diabetic patients. Infections usually begin in foot ulcers, which are associated with neuropathy, vasculopathy, and various metabolic disturbances. These infections are potentially limb and sometimes life threatening. Etiologic agents are usually aerobic gram-positive cocci, but chronic or serious infections often contain gram-negative rods and anaerobes. Chronic infections can lead to contiguous bone infection. Diagnosing osteomyelitis may require imaging studies (especially magnetic resonance imaging) and occasionally bone biopsy. In addition to proper cleansing, debridement, and local wound care, diabetic foot infections require carefully selected antibiotic therapy. Serious infections necessitate hospitalization for initial parenteral broad-spectrum antibiotic therapy, but appropriately selected patients with mild infections can be treated as outpatients with oral (or even topical) agents. Initial antibiotic selection is usually empiric; modifications may be needed based on the results of properly obtained cultures and the clinical response. Therapy should be active against staphylococci and streptococci, with broader-spectrum agents indicated if polymicrobial infection is likely. Levels of most antibiotics, except fluoroquinolones, are often subtherapeutic in infected foot tissues. The duration of therapy ranges from a week (for mild soft tissue infections) to over 6 weeks (for osteomyelitis). No single antibiotic agent or combination has proven to be optimal. With appropriate local, surgical, and antimicrobial therapy, most diabetic foot infections can now be successfully treated.

The role of beta-lactam/beta-lactamase inhibitors in the management of mixed infections

Microbiological studies show that the in vitro antimicrobial activity of sulbactam-ampicillin encompasses not only gram-positive and gram-negative aerobes, but also anaerobes. Such a broad spectrum of activity suggests its suitability as monotherapy for the empiric management of polymicrobial infections. Typical mixed infections, which are frequently life-threatening, include those occurring in the abdomen or pelvis, diabetic foot infections, and brain abscess. Numerous comparative clinical studies have revealed the clinical and bacteriological efficacy of sulbactam-ampicillin to be comparable to that of imipenem cilastatin and the second-generation cephalosporins cefoxitin and cefotetan. In addition, other studies have demonstrated that sulbactam-ampicillin monotherapy is cost-beneficial. A reduction in the duration of hospitalization, the lack of potentially toxic side-effects, and lower drug costs associated with monotherapy all contribute to the cost-effectiveness of sulbactam-ampicillin.

Efficacy and cost of ampicillin-sulbactam and ticarcillin-clavulanate in the treatment of hospitalized patients with bacterial infections

STUDY OBJECTIVE

To evaluate the efficacy and cost of treatment with two beta-lactam/beta-lactamase-inhibitor combinations.

DESIGN

Retrospective, open-label multicenter study.

SETTING

Fifty-four hospitals across the United States.

PATIENTS

Eight hundred ninety patients with skin and soft tissue, intraabdominal, gynecologic, respiratory, urinary tract, or other infections that required parenteral antibiotic therapy.

INTERVENTION

Patients were administered either ampicillin-sulbactam 1.5 or 3.0 g every 6 hours or ticarcillin-clavulanate 3.1 g every 6 hours.

MEASUREMENTS AND MAIN RESULTS

The agents did not differ significantly in efficacy for most infections; although, ampicillin-sulbactam was bacteriologically superior to ticarcillin-clavulanate in the treatment of intraabdominal infections (p=0.0011). Costs of ampicillin-sulbactam, particularly the 1.5-g dose, were lower than those of ticarcillin-clavulanate for skin and soft tissue (p<0.001), intraabdominal (p=0.005), and respiratory tract (p<0.001) infections.

CONCLUSION

Ampicillin-sulbactam provides effective coverage for patients with the above infections and is as effective as the broader-spectrum agent.

Cost-minimization analysis of piperacillin/tazobactam versus imipenem/cilastatin for the treatment of serious infections: a Canadian hospital perspective

BACKGROUND

In 1998 we reported the first Canadian double-blind, randomized, clinical trial involving a comparison of piperacillin/tazobactam (P/T) with imipenem/cilastatin (I/C). The present study was conducted to determine the feasibility of replacing I/C at our institution.

OBJECTIVE

To describe the outcome of a pharmacoeconomic analysis of the clinical trial from the perspective of a tertiary acute-care institution.

METHODS

A total of 150 consenting adults originally prescribed I/C were randomly assigned to receive either P/T 4.5 g i.v. (n = 75) or I/C 500 mg i.v. (n = 75) every six hours. Actual direct medical resources used in relation to the treatment of bacterial infections were prospectively assessed during a clinical trial; these included cost of study and ancillary antibiotics, hospitalization, diagnostic testing (radiology, laboratory assessments), and labor, as well as treatment of adverse drug reactions, antibiotic failures, and superinfections.

RESULTS

While costs for successful treatment courses were similar across treatment arms, hospitalization costs for treatment course failures were higher for P/T recipients. Direct medical costs for treatment courses associated with a superinfection were also higher in the P/T arm. Overall costs for treatment failures with either study drug were at least twofold those observed for successful treatment courses. Mean total management cost per patient in the P/T group was $15,211 ($ CDN throughout) (95% CI $11,429 to $18,993), compared with $14,232 (95% CI $11,421 to $17,043) in the I/C group (p = 0.32), resulting in a mean cost difference of $979. Sensitivity analyses revealed that the superiority of I/C over P/T for successful treatment of serious infections was sensitive to changes in the cost of hospitalization and drug efficacy for either drug.

CONCLUSIONS

Based on the results of the clinical trial, P/T and I/C offer similar clinical, microbiologic, and toxicity outcomes in hospitalized patients with serious infections. Under base-case conditions, our pharmacoeconomic analysis showed that I/C was a cost-effective alternative to P/T at the dosage regimens studied. However, this finding was sensitive to plausible changes in both clinical and economic parameters.