Randomized evaluation of ceftazidime or ticarcillin and tobramycin for the treatment of osteomyelitis caused by gram-negative bacilli

Differences in the Clinical Outcome of Osteomyelitis by Treating Specialty: Orthopedics or Infectology

Osteomyelitis is a heterogeneous infection with regard to etiology and treatment, and currently no single management protocol exists. Management of the condition is typically an interdisciplinary approach between orthopedics and infectious disease; however, the orthopedist is often the person who manages treatment. The aim of the study was to determine differences in the outcome of osteomyelitis according to its treating specialty and to identify factors associated with the recurrence of the disease. An ambispective cohort study of 129 patients with osteomyelitis was conducted and the proportions for qualitative variables and central tendency and dispersion measures for quantitative variables were calculated; the latter were tested for normality using the Shapiro-Wilk test. A bivariate analysis was conducted with measures of association based on the chi square test and crude relative risk. A logistic regression model was applied and statistical significance was set at p < 0.05, including the model of relevant clinical variables that fit the Hosmer-Lemeshow test. We found that 70% of patients were treated either by orthopedics or infectious disease. Patients who were treated by an orthopedist alone presented a greater risk of relapse or reinfection (RR = 4.6; 95% CI 2.3;8.9). Risk factors of osteomyelitis recurrence as determined in the regression model included the following: age of 57 years or older (RR = 1.3; 95% 0.3;5.2), long bones (RR = 1.9; 95% CI 0.5;7.1), fracture (RR = 5.0; 95% CI 0.4;51.4), monotherapy (RR = 3.0; 95% CI 0.6;14.5), receiving less than 4 weeks of antibiotics (RR = 1.5; 95% CI 0.2;10.1), inadequate treatment (RR = 3.1; 95% CI 0.4;20.1), and receiving orthopedics treatment (RR = 5.5; 95% CI 1.6;18.2). Most patients evaluated jointly by orthopedics and infectious disease received adequate treatment for osteomyelitis and had fewer relapses.

Beta lactam antibiotic monotherapy versus beta lactam-aminoglycoside antibiotic combination therapy for sepsis

BACKGROUND

Optimal antibiotic treatment for sepsis is imperative. Combining a beta lactam antibiotic with an aminoglycoside antibiotic may provide certain advantages over beta lactam monotherapy.

OBJECTIVES

Our objectives were to compare beta lactam monotherapy versus beta lactam-aminoglycoside combination therapy in patients with sepsis and to estimate the rate of adverse effects with each treatment regimen, including the development of bacterial resistance to antibiotics.

SEARCH METHODS

In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11); MEDLINE (1966 to 4 November 2013); EMBASE (1980 to November 2013); LILACS (1982 to November 2013); and conference proceedings of the Interscience Conference of Antimicrobial Agents and Chemotherapy (1995 to 2013). We scanned citations of all identified studies and contacted all corresponding authors. In our previous review, we searched the databases to July 2004.

SELECTION CRITERIA

We included randomized and quasi-randomized trials comparing any beta lactam monotherapy versus any combination of a beta lactam with an aminoglycoside for sepsis.

DATA COLLECTION AND ANALYSIS

The primary outcome was all-cause mortality. Secondary outcomes included treatment failure, superinfections and adverse events. Two review authors independently collected data. We pooled risk ratios (RRs) with 95% confidence intervals (CIs) using the fixed-effect model. We extracted outcomes by intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 69 trials that randomly assigned 7863 participants. Twenty-two trials compared the same beta lactam in both study arms, while the remaining trials compared different beta lactams using a broader-spectrum beta lactam in the monotherapy arm. In trials comparing the same beta lactam, we observed no difference between study groups with regard to all-cause mortality (RR 0.97, 95% CI 0.73 to 1.30) and clinical failure (RR 1.11, 95% CI 0.95 to 1.29). In studies comparing different beta lactams, we observed a trend for benefit with monotherapy for all-cause mortality (RR 0.85, 95% CI 0.71 to 1.01) and a significant advantage for clinical failure (RR 0.75, 95% CI 0.67 to 0.84). No significant disparities emerged from subgroup and sensitivity analyses, including assessment of participants with Gram-negative infection. The subgroup of Pseudomonas aeruginosa infections was underpowered to examine effects. Results for mortality were classified as low quality of evidence mainly as the result of imprecision. Results for failure were classified as very low quality of evidence because of indirectness of the outcome and possible detection bias in non-blinded trials. We detected no differences in the rate of development of resistance. Nephrotoxicity was significantly less frequent with monotherapy (RR 0.30, 95% CI 0.23 to 0.39). We found no heterogeneity for all these comparisons.We included a small subset of studies addressing participants with Gram-positive infection, mainly endocarditis. We identified no difference between monotherapy and combination therapy in these studies.

AUTHORS' CONCLUSIONS

The addition of an aminoglycoside to beta lactams for sepsis should be discouraged. All-cause mortality rates are unchanged. Combination treatment carries a significant risk of nephrotoxicity.

Antibiotics for treating chronic osteomyelitis in adults

BACKGROUND

Chronic osteomyelitis is generally treated with antibiotics and surgical debridement but can persist intermittently for years with frequent therapeutic failure or relapse. Despite advances in both antibiotic and surgical treatment, the long-term recurrence rate remains around 20%. This is an update of a Cochrane review first published in 2009.

OBJECTIVES

To determine the effects of different systemic antibiotic treatment regimens for treating chronic osteomyelitis in adults.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (October 2012), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2012, Issue 9), MEDLINE (January 1948 to September Week 4 2012), EMBASE (January 1980 to 2012 Week 40), LILACS (October 2012), the WHO International Clinical Trials Registry Platform (June 2012) and reference lists of relevant articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs addressing the effects of different antibiotic treatments given after surgical debridement for chronic osteomyelitis in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened papers for inclusion, extracted data and appraised risk of bias in the included trials. Where appropriate, we pooled data using the fixed-effect model.

MAIN RESULTS

We included eight small trials involving a total of 282 participants with chronic osteomyelitis. Data were available from 248 participants. Most participants were male with post-traumatic osteomyelitis, usually affecting the tibia and femur, where recorded. The antibiotic regimens, duration of treatment and follow-up varied between trials. All trials mentioned surgical debridement before starting on antibiotic therapy as part of treatment, but it was unclear in four trials whether all participants underwent surgical debridement.We found that study quality and reporting were often inadequate. In particular, we judged almost all trials to be at moderate to high risk of bias due to failure to conceal allocation and inadequate follow-up.Four trials compared oral versus parenteral route for administration of antibiotics. There was no statistically significant difference between the two groups in the remission at the end of treatment (70/80 versus 58/70; risk ratio (RR) 1.04, 95% confidence interval (CI) 0.92 to 1.18; four trials, 150 participants). There was no statistically significant difference between the two groups in the remission rate 12 or more months after treatment (49/64 versus 44/54; RR 0.94, 95% CI 0.78 to 1.13; three trials, 118 participants). There was also no significant difference between the two groups in the occurrence of mild adverse events (11/64 versus 8/54; RR 1.08, 95% CI 0.49 to 2.42; three trials, 118 participants) or moderate and severe adverse events (3/49 versus 4/42; RR 0.69, 95% CI 0.19 to 2.57; three trials, 91 participants). Superinfection occurred in participants of both groups (5/66 in the oral group versus 4/58 in the parenteral group; RR 1.08, 95% CI 0.33 to 3.60; three trials, 124 participants).Single trials with few participants found no statistical significant differences for remission or adverse events for the following four comparisons: oral only versus parenteral plus oral administration; parenteral plus oral versus parenteral only administration; two different parenteral antibiotic regimens; and two different oral antibiotic regimens. No trials compared different durations of antibiotic treatment for chronic osteomyelitis, or adjusted the remission rate for bacteria species or severity of disease.

AUTHORS' CONCLUSIONS

Limited and low quality evidence suggests that the route of antibiotic administration (oral versus parenteral) does not affect the rate of disease remission if the bacteria are susceptible to the antibiotic used. However, this and the lack of statistically significant differences in adverse effects need confirmation. No or insufficient evidence exists for other aspects of antibiotic therapy for chronic osteomyelitis.The majority of the included trials were conducted over 20 years ago and currently we are faced with a far higher prevalence of bacteria that are resistant to many of the available antibiotics used for healthcare. This continuously evolving bacterial resistance represents another challenge in the choice of antibiotics for treating chronic osteomyelitis.

Systemic antibiotic therapy for chronic osteomyelitis in adults

The standard recommendation for treating chronic osteomyelitis is 6 weeks of parenteral antibiotic therapy. However, oral antibiotics are available that achieve adequate levels in bone, and there are now more published studies of oral than parenteral antibiotic therapy for patients with chronic osteomyelitis. Oral and parenteral therapies achieve similar cure rates; however, oral therapy avoids risks associated with intravenous catheters and is generally less expensive, making it a reasonable choice for osteomyelitis caused by susceptible organisms. Addition of adjunctive rifampin to other antibiotics may improve cure rates. The optimal duration of therapy for chronic osteomyelitis remains uncertain. There is no evidence that antibiotic therapy for >4-6 weeks improves outcomes compared with shorter regimens. In view of concerns about encouraging antibiotic resistance to unnecessarily prolonged treatment, defining the optimal route and duration of antibiotic therapy and the role of surgical debridement in treating chronic osteomyelitis are important, unmet needs.

Antibiotics for treating chronic osteomyelitis in adults

BACKGROUND

Chronic osteomyelitis is generally treated with antibiotics and surgical debridement but can persist intermittently for years with frequent therapeutic failure. Despite advances in both antibiotics and surgical treatment, the long-term recurrence rate remains at approximately 20% to 30%.

OBJECTIVES

To determine the effects of different systemic antibiotic treatment regimens for treating chronic osteomyelitis in adults.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (October 2008), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2008, Issue 3), MEDLINE (January 1966 to October 2008), EMBASE (January 1980 to October 2008), LILACS (October 2008) and reference lists of relevant articles.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials addressing the effects of different antibiotic treatments given after surgical debridement for chronic osteomyelitis in adults.

DATA COLLECTION AND ANALYSIS

Two authors independently screened papers for inclusion, extracted data and appraised the quality of included trials. Where appropriate, we pooled data using the fixed-effect model.

MAIN RESULTS

We included eight small trials (257 participants in total, with data available from 228). Study quality was often inadequate: in particular, concealment of allocation was not confirmed and there was an absence of blinding of outcome assessment. The antibiotic regimens, duration of treatment and follow-up varied between trials. Five trials compared oral versus parenteral antibiotics. There was no statistically significant difference between the two groups in the remission rate 12 or more months after treatment (risk ratio 0.94, 95% confidence interval 0.78 to 1.13; 3 trials). Antibiotic treatment for osteomyelitis was associated with moderate or severe adverse events in 4.8% of patients allocated oral antibiotics and 15.5% patients allocated parenteral antibiotics (risk ratio: 0.40, 95% confidence interval 0.13 to 1.22; 4 trials). Single trials with very few participants found no statistical significant differences for remission or adverse events for the following three comparisons: parenteral plus oral versus parenteral only administration; two oral antibiotic regimens; and two parenteral antibiotic regimens. No trials compared different durations of antibiotic treatment for chronic osteomyelitis, or adjusted the remission rate for bacteria species or severity of disease.

AUTHORS' CONCLUSIONS

Limited evidence suggests that the method of antibiotic administration (oral versus parenteral) does not affect the rate of disease remission if the bacteria are sensitive to the antibiotic used. However, this and the lack of statistically significant differences in adverse effects need confirmation. No or insufficient evidence exists for other aspects of antibiotic therapy for chronic osteomyelitis.

Treatment of bone and joint infections caused by Gram-negative bacilli with a cefepime-fluoroquinolone combination

A 3-year retrospective study evaluated the effectiveness and safety of cefepime plus a fluoroquinolone for treating bone and joint infections caused by Gram-negative bacilli (GNB) in 28 patients. Intra-operative cultures yielded primarily Pseudomonas spp. and Enterobacter cloacae. Full recovery (cure) was observed in 79% of patients. There were no serious adverse effects and no resistant organisms were isolated. The results of the study confirmed the safety and effectiveness of cefepime combined with a fluoroquinolone for the treatment of bone and joint infections caused by Gram-negative bacilli.

Beta lactam antibiotic monotherapy versus beta lactam-aminoglycoside antibiotic combination therapy for sepsis

BACKGROUND

Optimal antibiotic treatment for sepsis is imperative. Combining a beta-lactam antibiotic with an aminoglycoside antibiotic may have certain advantages over beta-lactam monotherapy.

OBJECTIVES

We compared clinical outcomes for beta lactam-aminoglycoside combination therapy versus beta lactam monotherapy for sepsis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library, Issue 3, 2004); MEDLINE (1966 to July 2004); EMBASE (1980 to March 2003); LILACS (1982 to July 2004); and conference proceedings of the Interscience Conference of Antimicrobial Agents and Chemotherapy (1995 to 2003). We scanned citations of all identified studies and contacted all corresponding authors.

SELECTION CRITERIA

We included randomized and quasi-randomized trials comparing any beta-lactam monotherapy to any combination of one beta-lactam and one aminoglycoside for sepsis.

DATA COLLECTION AND ANALYSIS

The primary outcome was all-cause fatality. Secondary outcomes included treatment failure, superinfections, colonization, and adverse events. Two authors independently collected data. We pooled relative risks (RR) with their 95% confidence intervals (CI) using the fixed effect model. We extracted outcomes by intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 64 trials, randomizing 7586 patients. Twenty trials compared the same beta-lactam in both study arms, while the remaining compared different beta-lactams using a broader spectrum beta-lactam in the monotherapy arm. In studies comparing the same beta-lactam, we observed no difference between study groups with regard to all-cause fatality, RR 1.01 (95% CI 0.75-1.35) and clinical failure, RR 1.11 (95% CI 0.95-1.29). In studies comparing different beta-lactams, we observed an advantage to monotherapy: all cause fatality RR 0.85 (95% CI 0.71-1.01), clinical failure RR 0.77 (95% CI 0.69-0.86). No significant disparities emerged from subgroup and sensitivity analyses, including the assessment of patients with Gram-negative and Pseudomonas aeruginosa infections. We detected no differences in the rate of resistance development. Adverse events rates did not differ significantly between the study groups overall, although nephrotoxicity was significantly more frequent with combination therapy, RR 0.30 (95% CI 0.23-0.39). We found no heterogeneity for all comparisons. We included a small subset of studies addressing patients with Gram-positive infections, mainly endocarditis. We identified no difference between monotherapy and combination therapy in these studies.

AUTHORS' CONCLUSIONS

The addition of an aminoglycoside to beta-lactams for sepsis should be discouraged. All-cause fatality rates are unchanged. Combination treatment carries a significant risk of nephrotoxicity.

Effect of Aminoglycoside and β‐Lactam Combination Therapy versus β‐Lactam Monotherapy on the Emergence of Antimicrobial Resistance: A Meta‐analysis of Randomized, Controlled Trials

BACKGROUND

The addition of an aminoglycoside to a beta -lactam therapy regimen has been suggested to have a beneficial effect in delaying or preventing the development of antimicrobial resistance. We studied the effect of aminoglycoside/ beta -lactam combination therapy versus beta-lactam monotherapy on the emergence of resistance.

METHODS

We performed a meta-analysis of randomized, controlled trials (RCTs) that compared aminoglycoside/ beta-lactam combination therapy with beta-lactam monotherapy and that reported data regarding the emergence of resistance (primary outcome) and/or development of superinfection, treatment failure, treatment failure attributable to emergence of resistance, treatment failure attributable to superinfection, all-cause mortality during treatment, and mortality due to infection. Data for this meta-analysis were identified from the PubMed database, Current Contents database, Cochrane central register of controlled trials, and references in relevant articles.

RESULTS

A total of 8 RCTs were included in the analysis. Beta -lactam monotherapy was not associated with a greater emergence of resistance than was the aminoglycoside/ beta-lactam combination (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.56-1.47). Actually, beta -lactam monotherapy was associated with fewer superinfections (OR, 0.62; 95% CI, 0.42-0.93) and fewer treatment failures (OR, 0.62; 95% CI, 0.38-1.01). Rates of treatment failure attributable to emergence of resistance (OR, 3.09; 95% CI, 0.75-12.82), treatment failure attributable to superinfection (OR, 0.60; 95% CI, 0.33-1.10), all-cause mortality during treatment (OR, 0.70; 95% CI, 0.40-1.25), and mortality due to infection (OR, 0.74; 95% CI, 0.46-1.21) did not differ significantly between the 2 regimens.

CONCLUSIONS

Compared with beta-lactam monotherapy, the aminoglycoside/ beta-lactam combination was not associated with a beneficial effect on the development of antimicrobial resistance among initially antimicrobial-susceptible isolates.

Systematic review and meta-analysis of antibiotic therapy for bone and joint infections

We set out to evaluate the clinical efficacy of individual antibiotic agents for bone and joint infections in adults. Published and unpublished controlled trials reported between 1966 and 2000 were reviewed to determine if they involved random or quasi-random allocation to systemically administered antimicrobials or local antibiotic therapy for osteomyelitis and septic arthritis. Quiescence of infection after 1 year of follow-up was defined as the primary outcome measure. 22 trials containing 927 patients were eligible for final analysis. Varying proportions of the entire study population could be evaluated with respect to primary and secondary endpoints. Methodological quality was poor among most studies, and interpretability of results was further limited by small sample sizes, missing descriptions of patient populations and disease characteristics, and the frequent application of concomitant antibiotics. A trend towards improved, long-lasting infection control was observed in favour of a rifampicin-ciprofloxacin combination versus ciprofloxacin monotherapy for the treatment of staphylococcal infections related to orthopaedic devices (absolute risk difference [ARD] 28-9%; 95% CI -0.7 to 54.4%). Obviously unbalanced comparative studies showed some benefit of ticarcillin for bone infections caused by Pseudomonas species. No significant differences in therapeutic efficacy were found among trials comparing oral fluoroquinolones with intravenous beta-lactam drugs for both end-of-treatment (OR 0.8; 0.5 to 1.4) and long-term results (OR 1.3; 0.8 to 2.1). A variety of drugs was used as controls, thereby leading to inconsistent findings of drug-related side effects. Only one randomised trial was suitable to investigate the impact of polymethylmethacrylate gentamicin bead chains compared with parenteral antibiotics for skeletal infections, although this study was biased by patients receiving both combined local and systemic antibiotic therapy. Whereas intention-to-treat evaluation suggested a therapeutic advantage of systemic over local therapy, this trend diminished in the per-protocol analysis (1-year follow-up ARD -2.3;-17.5 to 10.8%). There exists little high-quality evidence on antibiotic therapy for osteomyelitis and septic arthritis. The observed heterogeneity among patient populations and medical and surgical treatment concepts preclude reliable inferences from the available data.

Bacterial osteomyelitis in adults: evolving considerations in diagnosis and treatment

Bacterial osteomyelitis causes substantial morbidity worldwide, despite continued progress toward understanding its pathophysiology and optimal management. The approach to osteomyelitis depends upon the route by which bacteria gained access to bone, bacterial virulence, local and systemic host immune factors, and patient age. While imaging studies and nonspecific blood tests may suggest the diagnosis, an invasive technique is generally required to identify the causative pathogens. Given the paucity of comparative clinical trials, antibacterial regimen selection has been largely guided by knowledge of the relative activities and pharmacokinetics of individual drugs, supported by data from animal models. Definitive therapy often requires a combined medical and surgical approach. Newer microvascular and distraction osteogenesis techniques and the use of laser doppler allow more complete surgical resection of infected material while maintaining function. Despite recent advances, many patients with osteomyelitis fail aggressive medical and surgical therapy. More accurate diagnostic methods, better ways to assess and monitor the effectiveness of therapy, and novel approaches to eradicate sequestered bacteria are needed.

Ceftazidime. An update of its antibacterial activity, pharmacokinetic properties and therapeutic efficacy

Ceftazidime is a third generation cephalosporin antibacterial agent which, since its introduction in the early 1980s, has retained a broad spectrum of in vitro antimicrobial activity and clinical utility in serious infections. However, increasing resistance to ceftazidime and other third generation cephalosporins, particularly among Enterobacteriaceae, due to the emergence of plasmid-mediated extended spectrum beta-lactamases and the class I chromosomally mediated beta-lactamases, is of concern. There is now a wealth of information on the pharmacokinetics of the drug. enabling ceftazidime to be used predictably, and with a low potential for adverse effects, in a diversity of patient populations. Overall, ceftazidime remains an effective agent for the treatment of serious infection, particularly those due to major nosocomial pathogens, and respiratory infections in patients with cystic fibrosis. Ceftazidime-containing regimens also remain an important option for the empirical therapy of febrile episodes in neutropenic patients. The tolerability profile of ceftazidime makes the drug a useful option in seriously ill patients who are at risk of developing adverse events with other antibacterial agents. Although patterns of bacterial resistance have changed in the ensuing years since its introduction, judicious use of this important agent will help maintain its present clinical utility.

The mode of action of quinolones: the paradox in activity of low and high concentrations and activity in the anaerobic environment

All 4-quinolones that have been examined display rapid bactericidal activity which is biphasic. At concentrations above the MIC, the lethality of the drugs increases until a concentration known as the optimum bactericidal concentration (OBC) beyond which the bactericidal activity then declines. The biphasic response appears to be due to the inhibition of RNA synthesis at concentrations above the OBC, as RNA synthesis is required for the full bactericidal activity of the 4-quinolones. However, differences in the biphasic response are observed as some fluoroquinolones are still able to kill bacteria in the absence of bacterial protein or RNA synthesis, thus reducing the inhibition of bactericidal activity at concentrations above the OBC. It has been proposed that this ability to kill bacteria in the absence of protein or RNA synthesis is due to the possession of an additional bactericidal mechanism by these fluoroquinolones. Oxygen also appears to be essential for the lethality of the clinically available 4-quinolones although it is not required for the drugs to inhibit bacterial multiplication. Therefore these drugs are not bactericidal under anaerobic conditions.

Ceftazidime as single-agent therapy for gram-negative aerobic bacillary osteomyelitis

The cases of 28 patients who received ceftazidime as single-agent therapy in prospective clinical trials for biopsy culture-proven osteomyelitis were reviewed. These cases all involved infection caused by gram-negative aerobic bacilli, the most frequent agent (83% of patients) being Pseudomonas aeruginosa. Posttreatment follow-up for patients with acute osteomyelitis was continued for at least 6 months, while follow-up for at least 12 months was done for patients with chronic osteomyelitis. A regimen of 2 g of ceftazidime intravenously every 12 h was used for most patients. The overall cure rates were 77% (acute disease) and 60% (chronic disease). Development of resistance to ceftazidime was not problematic, and the drug was well tolerated. Ceftazidime is effective for serious gram-negative bacillary osteomyelitis, including that due to P. aeruginosa. The twice-daily regimen did not cause major organ toxicity, eliminating the need for concentration monitoring and making it feasible to use the drug for home parenteral therapy.