Ceftriaxone therapy for staphylococcal osteomyelitis: a review

Synthesis of novel antibacterial nanocomposite CuO/Ag-modified zeolite for removal of MB dye

Novel CuO/Ag nanocomposites added zeolite (CAZ) were successfully fabricated, and their effectiveness as an antibacterial on S. aureus and MB removal was evaluated. EDX, XRD, and FTIR confirm the presence of the elemental compositions of CAZ. Friable CuO nanorods (10-70 nm in diameter) existed on the surface of the zeolite. Pure zeolite had a higher band gap (5.433 eV) and lower MB removal efficiency than CAZ. The adsorption method by CAZ was more effective at removing MB than photodegradation. 0.10 CAZ had the highest removal effectiveness (~ 99%) and adsorption capacity (~ 70.4 mg g-1) of MB. The inhibitory zone diameter for 0.005 CAZ against S. aureus was 20 mm, while 0.01 CAZ had a diameter of 17 mm. Azithromycin, ceftriaxone, and erythromycin antibiotics demonstrated lower or no efficacy against S. aureus than CAZ. Significant antibacterial activities and wastewater treatment were achieved by CAZ. The combination of photodegradation and adsorption enhanced pollutant removal. It will be interesting to study further the optimal molar ratio for MB removal (0.10 CAZ) in future investigations.

Ceftriaxone and methicillin-susceptible staphylococcus aureus: a perspective from pharmacokinetics/pharmacodynamics studies

INTRODUCTION

: Usage of ceftriaxone-based therapy to treat Methicillin-Susceptible Staphylococcus aureus (MSSA) infections is a controversial issue, from in vitro to clinical studies.

AREA COVERED

: We conducted a literature review using PubMed of articles with ceftriaxone pharmacokinetics parameters and built a probability of target attainment (PTA) based on PK values from stable conditions (non-critically-ill patients) with goals of fT>55%, fT>75%, and fT>100%. Ceftriaxone's minimal inhibitory concentration from 31 MSSA strains (0.25-64mg/L) was used to build the cumulative fraction response (CFR). The isolates were clinically relevant from blood, bronchoalveolar lavage, and soft tissue biopsy.

EXPERT OPINION

The results from controversies about using ceftriaxone for MSSA infections have been commonly addressed in the literature. However, variables such as (i) pharmacokinetic profile, (ii) pharmacodynamic target, (iii) site of infection, and (iv) MIC distributions may influence divergences. From this pharmacokinetics-pharmacodynamics perspective, ceftriaxone may be a reasonable option for MSSA infections when the MIC50 and MIC90 were 4mg/L and 8mg/L. CFR analysis demonstrated that ceftriaxone 1g q24h could be used if bacteriostasis is the aim (fT>55%), while 1g q12h should be used for bactericidal effects (fT>75% or fT>100%). Since there is a lack of data from clinical trials, the findings should be interpreted cautiously.

Acute infectious osteomyelitis in children: new treatment strategies for an old enemy

BACKGROUND

Acute osteomyelitis still represents a significant clinical challenge, with an increasing incidence in paediatric population. A careful assessment and a rapid diagnosis with proper timing and choice of empirical antimicrobial therapy are necessary to avoid sequelae. The initial treatment should consist of empirical antibiotic therapy, to cover the major responsible pathogens in each age group.

DATA SOURCES

We made a literature search with PubMed and Cochrane database from 2000 to 2019 in English, French, and Spanish languages using the key words "osteomyelitis, children, clinical, diagnosis, and treatment".

RESULTS

The child's clinical features, age, and the microbiological profile of the geographic area should be evaluated for diagnosis and in the choice of antibiotic treatment. Latest data suggest the administration of intravenous antibiotics for a short period, with subsequent oral therapy, according to the improvement of clinical status and inflammatory markers. For children older than 3 months, the shift to oral medications is already possible after a short course of intravenous therapy, until recovery. The timing for the shift from cefazolin to cephalexin or cefuroxime, intravenous clindamycin to oral clindamycin, and intravenous ceftriaxone + oxacillin to oral equivalents will be decided according to the improvement of clinical status and inflammatory markers. We also present the approach to osteomyelitis due to difficult pathogens, such as Methicillin-resistant Staphylococcus aureus (MRSA) and Panton-Valentine leukocidin (PVL)-positive S. aureus infections.

CONCLUSION

In this review, we present the current approach to the clinical diagnosis and management of osteomyelitis in childhood, with an update on recent recommendations, as a useful instrument to understand the rationale of antibiotic therapy.

A multifunctional bioactive material that stimulates osteogenesis and promotes the vascularization bone marrow stem cells and their resistance to bacterial infection

The main limitation of tissue engineering lies in the inability to stimulate osteogenesis, angiogenesis of stem cells and broad-spectrum antimicrobial activity. However, the development of multifunctional bioactive materials with these capabilities remains a great challenge. In this study, we prepared mesoporous silica nanoparticles encapsulated with silver nanocrystals (AG-MSN) with uniform sphere size and mesopores. Platelet-derived growth factor BB (PDGF-BB) was effectively loaded in the AG-MSN mesopores (P-AG-MSN). The silicon ions (Si) released by P-AG-MSN stimulate osteogenic differentiation of bone marrow stromal cells (BMSC) by activating the alkaline phosphatase (ALP) activity of bone-related genes and increasing protein (OCN, RUNX2 and OPN) expression. Ag+ ions could be slowly released from the interior of the shell, highlighting their durable antibacterial activity. The sustained release of PDGF-BB from P-AG-MSN stimulated the angiogenic differentiation of BMSC, as indicated by the enhanced secretion of vascular endothelial growth factor (VEGF), HIF-1α, HGF and ANG-1 and protein expression. Our results show that P-AG-MSN can clearly promote BMSC osteostimulation and vascularization. This research serves as a preliminary study of the utilization of this multifunctional mixture to fabricate a new active biological scaffold that integrates BMSC osteostimulation, vascularization and bactericidal effects by 3D printing technology.

Ceftriaxone susceptibility of oxacillin-susceptible Staphylococcus aureus from patients with prosthetic joint infection

Ceftriaxone is used to treat oxacillin-susceptible S. aureus (OSSA) prosthetic joint infection (PJI). Susceptibility of ceftriaxone against OSSA has been questioned. Ceftriaxone susceptibility was determined against 100 PJI OSSA isolates. Ceftriaxone MIC90/MIC50 were 8/4 and 4/3μg/mL by broth microdilution and Etest, respectively. Ceftriaxone susceptibility is inferable by oxacillin susceptibility.

Evaluating the use of antibiotic prophylaxis during open reduction and internal fixation surgery in patients at low risk of surgical site infection

BACKGROUND

Widespread overuse and inappropriate use of antibiotics contribute to increasingly antibiotic-resistant pathogens and higher health care costs. It is not clear whether routine antibiotic prophylaxis can reduce the rate of surgical site infection (SSI) in low-risk patients undergoing orthopaedic surgery. We designed a simple scorecard to grade SSI risk factors and determined whether routine antibiotic prophylaxis affects SSI occurrence during open reduction and internal fixation (ORIF) orthopaedic surgeries in trauma patients at low risk of developing SSI.

METHODS

The SSI risk scorecard (possible total points ranged from 5 to 25) was designed to take into account a patient's general health status, the primary cause of fractures, surgical site tissue condition or wound class, types of devices implanted, and surgical duration. Patients with a low SSI risk score (≤8 points) who were undergoing clean ORIF surgery were divided into control (routine antibiotic treatment, cefuroxime) and evaluation (no antibiotic treatment) groups and followed up for 13-17 months after surgery.

RESULTS

The infection rate was much higher in patients with high SSI risk scores (≥9 points) than in patients with low risk scores assigned to the control group (10.7% vs. 2.2%, P<0.0001). SSI occurred in 11 of 499 patients in the control group and in 13 of 534 patients in the evaluation group during the follow-up period of 13-17 months. The SSI occurrence rate did not differ significantly (2.2% vs. 2.4%, P=0.97) between the control and evaluation groups.

CONCLUSIONS

Routine antibiotic prophylaxis does not significantly decrease the rate of SSI in ORIF surgical patients with a low risk score. Implementation of this scoring system could guide the rational use of perioperative antibiotics and ultimately reduce antibiotic resistance, health care costs, and adverse reactions to antibiotics.

Bacteremia with an iliopsoas abscess and osteomyelitis of the femoral head caused by Enterococcus avium in a patient with end-stage kidney disease

A 70-year-old man on hemodialysis for end-stage kidney disease due to polycystic kidney disease presented with hip pain on extension and a high C-reactive protein level. Further examinations revealed an iliopsoas abscess and femoral head osteomyelitis caused by Enterococcus avium (E. avium) detected in blood and pus cultures. Complete resolution of the infection with ampicillin-resistant E. avium required six months of vancomycin therapy and two surgical drainage procedures. There have been no previous case reports in which both blood and abscess cultures confirmed E. avium infection. Careful attention should be paid to the detection of non-specific symptoms in patients on hemodialysis, with blood cultures being essential in such cases.

Common Occurrence of Ceftriaxone-Resistant, Methicillin-Sensitive Staphylococcus aureus at a Community Teaching Hospital

"Common Occurrence of Ceftriaxone-Resistant, Methicillin-Sensitive Staphylococcus aureus at a Community Teaching Hospital" by Aaron J. Pickering, Rahman Hariri, Lee H. Harrison, Jane W. Marsh, Amatullah Tasneem, Henry Freedy, Laura Wilson, and Hector Bonilla. [Clin Infect Dis. (2014), doi:10.1093/cid/ciu149]. Due to an honest error in the interpretation of a key lab test by the study microbiologist, with approval of all authors cited above, the authors are retracting this article from Clinical Infectious Diseases.

Invasive Staphylococcus aureus infections in diabetes mellitus

Staphylococcus aureus, the most virulent of the many staphylococcal species, has remained a major cause of morbidity and mortality despite the availability of numerous effective anti-staphylococcal antibiotics. S. aureus causes disease through both toxin-mediated and non-toxin-mediated mechanisms. This organism is responsible for both healthcare associated and community-based infections ranging from relatively minor skin and soft tissue infections to severe life threatening systemic infections. Patients with diabetes mellitus are at increased risk of invasive S. aureus infections. This article focuses on the spectrum of invasive S. aureus infections and discusses the clinical features, investigations and management of these infections in patients with diabetes mellitus.

The Effectiveness and Safety of Oral Linezolid for the Primary and Secondary Treatment of Osteomyelitis

The pharmacokinetic profile of oral linezolid makes it an attractive alternative for the treatment of osteomyelitis. Few studies have described the efficacy of linezolid in the treatment of osteomyelitis. A retrospective, observational analysis was conducted at Edward Hines, Jr. VA Hospital. Patients who received oral linezolid from June 2000 to December 2002 were identified from pharmacy records. Forty-two patients who received oral linezolid for osteomyelitis at our institution were identified. Only patients who had received at least six weeks of linezolid therapy were evaluated for clinical effectiveness. Patients were also evaluated for adverse drug reactions due to linezolid. The clinical cure rate was 55% for the 20 patients who received at least six weeks of therapy. Adverse events included gastrointestinal disturbances (15%), thrombocytopenia (10%), anemia (10%), neutropenia (5%) and rash (5%). The authors conclude that oral linezolid is an alterative to intravenous antibiotics for the treatment of osteomyelitis.

Diabetic mouse model of orthopaedic implant-related Staphylococcus aureus infection

Background

Periprosthetic bacterial infections represent one of the most challenging orthopaedic complications that often require implant removal and surgical debridement and carry high social and economical costs. Diabetes is one of the most relevant risk factors of implant-related infection and its clinical occurrence is growing worldwide. The aim of the present study was to test a model of implant-related infection in the diabetic mouse, with a view to allow further investigation on the relative efficacy of prevention and treatment options in diabetic and non-diabetic individuals.

Methodology

A cohort of diabetic NOD/ShiLtJ mice was compared with non-diabetic CD1 mice as an in vivo model of S. aureus orthopaedic infection of bone and soft tissues after femur intramedullary pin implantation. We tested control and infected groups with 1×10³ colony-forming units of S. aureus ATCC 25923 strain injected in the implant site. At 4 weeks post-inoculation, host response to infection, microbial biofilm formation, and bone damage were assessed by traditional diagnostic parameters (bacterial culture, C-reactive protein and white blood cell count), histological analysis and imaging techniques (micro computed tomography and scanning electron microscopy).

Results

Unlike the controls and the CD1 mice, all the diabetic mice challenged with a single inoculum of S. aureus displayed severe osteomyelitic changes around the implant.

Conclusions

Our findings demonstrate for the first time that the diabetic mouse can be successfully used in a model of orthopaedic implant-related infection. Furthermore, the same bacteria inoculum induced periprosthetic infection in all the diabetic mice but not in the controls. This animal model of implant-related infection in diabetes may be a useful tool to test in vivo treatments in diabetic and non-diabetic individuals.

Outpatient parenteral antimicrobial therapy for the treatment of methicillin-susceptible Staphylococcus aureus: a comparison of cefazolin and ceftriaxone

PURPOSE

Although the antistaphylococcal penicillins remain the drugs of choice for methicillin-susceptible Staphylococcus aureus (MSSA) infections, cefazolin and ceftriaxone are often prescribed due to their less frequent dosing and reduced cost. The purpose of this study was to compare clinical outcomes and adverse events in patients receiving outpatient parenteral antimicrobial therapy (OPAT) with ceftriaxone or cefazolin for the treatment of MSSA infections.

METHODS

A retrospective study was carried out of 122 patients evaluated at Ben Taub and Lyndon B. Johnson General Hospitals in Houston, Texas, between January 1, 2006, and March 31, 2012, with a documented MSSA infection who received cefazolin or ceftriaxone as OPAT. A favorable clinical outcome was determined by their primary care physician's assessment at follow-up in the clinic.

RESULTS

Out of 122 patients, 78 (64 %) were treated with cefazolin and 44 (36 %) with ceftriaxone. Patients were predominantly young (median age 46 years), male (54.2 %), and Hispanic (51.2 %). Patients were similar in terms of baseline demographics, types of infections, and management of infections. Favorable clinical outcomes were similar between cefazolin and ceftriaxone (67.9 versus 79.8 %, p = 0.17), along with a similar incidence of adverse events and complications (5.1 versus 2.3 %, p = 0.65, and 26.9 versus 18.2 %, p = 0.38, respectively).

CONCLUSIONS

OPAT with either cefazolin or ceftriaxone is similar in terms of favorable outcomes, adverse events, and complications when treating MSSA infections. A randomized clinical trial is needed in order to confirm these results.

Biodegradable vs non-biodegradable antibiotic delivery devices in the treatment of osteomyelitis

INTRODUCTION

Chronic osteomyelitis, or bone infection, is a major worldwide cause of morbidity and mortality, as it is exceptionally hard to treat due to patient and pathogen-associated factors. Successful treatment requires surgical debridement together with long-term, high antibiotic concentrations that are best achieved by local delivery devices, either made of degradable or non-degradable materials.

AREAS COVERED

Non-degradable delivery devices are frequently constituted by polymethylmethacrylate-based carriers. Drawbacks are the need to remove the carrier (as the carrier itself may provide a substratum for bacterial colonization), inefficient release kinetics and incompatibility with certain antibiotics. These drawbacks have led to the quest for degradable alternatives, but also devices made of biodegradable calcium sulphate, collagen sponges, calcium phosphate or polylactic acids have their specific disadvantages.

EXPERT OPINION

Antibiotic treatment of osteomyelitis with the current degradable and non-degradable delivery devices is effective in the majority of cases. Degradable carriers have an advantage over non-degradable carriers that they do not require surgical removal. Synthetic poly(trimethylene carbonate) may be preferred in the future over currently approved lactic/glycolic acids, because it does not yield acidic degradation products. Moreover, degradable poly(trimethylene carbonate) yields a zero-order release kinetics that may not stimulate development of antibiotic-resistant bacterial strains due to the absence of long-term, low-concentration tail-release.

Diagnosis and management of prosthetic joint infection: clinical practice guidelines by the Infectious Diseases Society of America

These guidelines are intended for use by infectious disease specialists, orthopedists, and other healthcare professionals who care for patients with prosthetic joint infection (PJI). They include evidence-based and opinion-based recommendations for the diagnosis and management of patients with PJI treated with debridement and retention of the prosthesis, resection arthroplasty with or without subsequent staged reimplantation, 1-stage reimplantation, and amputation.

Aspergillus osteomyelitis of the proximal humerus: a case report

Aspergillus osteomyelitis is an extremely rare manifestation of invasive aspergillosis. Generally, patients in states of significant immune deficiency are very susceptible to invasive aspergillosis. We report a case of Aspergillus osteomyelitis of the proximal humerus in an immunocompetent patient that required aggressive oral antifungal therapy, surgical debridement, and placement of an antifungal-impregnated cement spacer. Subsequently, her shoulder was reconstructed using a reverse total shoulder prosthesis The clinical course, radiographic findings, histology, and management rationale are presented.

A retrospective comparison of ceftriaxone versus oxacillin for osteoarticular infections due to methicillin-susceptible Staphylococcus aureus

BACKGROUND

Antistaphylococcal penicillins are the treatment of choice for methicillin-susceptible Staphylococcus aureus (MSSA) infection. Ceftriaxone can be dosed once daily and is less expensive for outpatient therapy than oxacillin. We compared patient outcomes of MSSA osteoarticular infections treated with ceftriaxone versus oxacillin.

METHODS

We conducted a retrospective cohort study of patients with MSSA osteoarticular infections at a tertiary care hospital from January 2005 to April 2010. We collected demographic, clinical, and outcome data including treatment-related adverse events. Successful treatment (clinical improvement; improved follow-up markers and imaging; no readmission for treatment) was compared at 3-6 months and >6 months after completion of intravenous antibiotics.

RESULTS

In total, 124 patients had an MSSA osteoarticular infection; 64 (52%) had orthopedic hardware involvement. Of those patients, 74 (60%) received ceftriaxone and 50 (40%) received oxacillin. Oxacillin was more often discontinued due to toxicity (9 of 50 [18%] oxacillin vs 3 of 74 [4%] ceftriaxone; P = .01). At 3-6 and >6 months, data for 97 and 88 patients, respectively, were available for analysis. Treatment success was similar at 3-6 months (50 of 60 [83%] ceftriaxone vs 32 of 37 [86%] oxacillin; P = .7) and >6 months (43 of 56 [77%] ceftriaxone vs 26 of 32 [81%] oxacillin; P = .6). After intravenous antibiotics, 56 (45%) patients received long-term suppression with oral antibiotics (31 of 74 [42%] ceftriaxone vs 25 of 50 [50%] oxacillin; P = .4).

CONCLUSIONS

In this comparison of ceftriaxone versus oxacillin for MSSA osteoarticular infections, there was no difference in treatment success at 3-6 and >6 months following the completion of intravenous antibiotics. Patients receiving oxacillin were more likely to have it discontinued due to toxicity.

Systemic antimicrobial therapy in osteomyelitis

Appropriately designed antibiotic regimens are critical to the management of all stages of osteomyelitis, although goals of therapy may vary in different stages of infection. The most important consideration for antibiotic selection is spectrum of action. Route of administration by intravenous or oral route is less important than drug levels that are achievable at the site of infection. Outpatient parenteral therapy and use of oral agents has simplified delivery of long-term treatment regimens. There are few high-quality studies that compare specific treatment regimens or durations of therapy, and recommendations for drugs and duration of antibiotic therapy are based on expert opinion, case series, and extrapolations from animal models. Intravenous beta-lactams are the treatment of choice for methicillin-susceptible Staphylococcus aureus, but there are also oral options available. Vancomycin has been the treatment of choice for methicillin-resistant Staphylococcus aureus osteomyelitis, but there are several newer parenteral and oral agents for treatment of methicillin-resistant Staphylococcus aureus including linezolid and daptomycin. Rifampin combined with other staphylococcal agents may increase cure rates, especially for device-associated infections. Oral fluoroquinolones and parenteral beta-lactam agents can be used for treatment of gram-negative osteomyelitis, but increasing resistance has complicated management of these infections.

Determination of an inoculum effect with various cephalosporins among clinical isolates of methicillin-susceptible Staphylococcus aureus

Using 98 clinical methicillin-susceptible Staphylococcus aureus isolates of known beta-lactamase (Bla) type, we found a pronounced inoculum effect for cephalexin (mostly Bla type A and C strains), a mild inoculum effect for cephalothin (especially types B and C), and no inoculum effects for ceftriaxone and cefuroxime. Ceftobiprole showed the lowest MICs at a high inoculum but with a slight increase for Bla-positive versus Bla-negative strains. Since a potential therapeutic effect associated with a cephalosporin inoculum effect has been described, further studies are warranted.

Outpatient parenteral antibiotic therapy for bone and joint infections: an italian multicenter study

In the early eighties, the advantages of outpatient parenteral antibiotic therapy (OPAT) (reduced costs, no hospitalization trauma in children, no immobilization syndrome in elderly, reduction in nosocomial infections by multiresistant organisms) were identified in the United States, and suitable therapeutic programs were established. Currently, more than 250,000 patients per year are treated according to an OPAT program. In order to understand the different ways of managing OPAT and its results, a National OPAT Registry was set up in 2003 in Italy. Analysis of data concerning osteomyelitis, septic arthritis, prosthetic joint infection and spondylodiskitis, allowed information to be acquired about 239 cases of bone and joint infections, with particular concern to demographics, therapeutic management, clinical response, and possible side effects. Combination therapy was the first-line choice in 66.9% of cases and frequently intravenous antibiotics were combined with oral ones. Teicoplanin (38%) and ceftriaxone (14.7%), whose pharmacokinetic/pharmacodynamic properties permit once-a-day administration, were the two top antibiotics chosen; fluoroquinolones (ciprofloxacin and levofloxacin) were the most frequently utilized oral drugs. Clinical success, as well as patients' and doctors' satisfaction with the OPAT regimen was high. Side-effects were mild and occurred in 11% of cases. These data confirm that the management of bone and joint infections in an outpatient setting is suitable, effective and safe.

Optimising Antimicrobial Therapy in Diabetic Foot Infections

Foot infections are common and the most serious lower extremity complication contributing to amputations, particularly in patients with diabetes mellitus. Infection is most often a consequence of foot ulcerations, which typically follows trauma to a neuropathic foot. Foot infections may be classified as mild, moderate and severe; this largely determines the approach to therapy. Gram-positive bacteria are the sole causative pathogens for most mild and moderate infections. These infections can usually be treated with culture-based narrow-spectrum antibacterials along with appropriate surgical debridement in an outpatient setting. In contrast, severe infections are often polymicrobial, requiring hospitalisation and treatment with broad-spectrum antibacterials along with appropriate medical and surgical interventions. The initial empirical antibacterial regimen may be tailored based on the results of culture and sensitivity tests from properly obtained specimens. Several antibacterial regimens have demonstrated effectiveness in randomised controlled trials, but no single regimen has shown superiority. Managing diabetic foot osteomyelitis is particularly controversial and requires reliable cultures to select an appropriate antibacterial regimen. Surgical resection of the infected and necrotic bone favours a good outcome in chronic osteomyelitis. The recommended duration of antibacterial therapy ranges from 1 to 4 weeks for soft tissue infection, to >6 weeks for unresected osteomyelitis. The incidence of meticillin-resistant Staphylococcus aureus infection is increasing in both the healthcare setting and the community. This should be considered when selecting an antibacterial, especially if the patient does not improve with initial antibacterial therapy. Certain other organisms, such as Pseudomonas aeruginosa and Enterococcus spp., while potentially pathogenic, are often colonisers that do not require targeted therapy.

Antibioterapia intravenosa en domicilio. Estudio de 515 casos

OBJECTIVE

To assess the effectiveness of therapy, type of infection, hospital department of origin and outcome of 515 cases of infection requiring home intravenous antibiotic therapy treated by the home care service.

METHODS

The clinical records of patients undergoing intravenous antibiotic therapy through the home care service over a 6-year period were retrospectively reviewed.

RESULTS

A total of 439 patients (244M/195F; mean age, 55.9 years, range 7-96) requiring 515 courses of home intravenous antibiotic therapy were reviewed. Mean duration of antibiotic therapy was 7.9 days (1-58). Urinary (42.3%) and respiratory infections (25.8%) were the most frequent indications for home treatment. Most patients were referred from the emergency room (50.5%) followed by the Internal Medicine Department (11.5%) and Oncology Department (11.1%). Ceftriaxone was the most widely prescribed antibiotic (41.8%) followed by aminoglycosides (35.3%) and glycopeptides (11.7%). In 49 cases electronic infusion pumps were used, with ceftazidime being the predominant antibiotic (32.7%) in these cases. Hospitalization was required in 7% of patients due to infectious disease-related complications. Clinical outcome was positive in 79% of the patients, with improvement in 90% of patients from the emergency room

CONCLUSIONS

The advantages of home care services to provide home intravenous antibiotic therapy are evident. More than half of the patients were referred from the emergency room and 90% of these progressed well. The presence of medical and nursing staff qualified to handle infectious diseases is necessary, as well as continuing home care.

Antibiotic susceptibility of bacteria most commonly isolated from bone related infections: the role of cephalosporins in antimicrobial therapy

Bone infections, which can be acute or chronic, often require aggressive antibiotic therapy, whether treated at home or in the community. Surveillance programmes are essential tools in the monitoring of antimicrobial resistance and can act as a resource to maintain effective prescribing. The Surveillance Network (TSN), which collects organism and patient-specific data from a network of laboratories across the United States, was used to analyse susceptibility of common bacterial species isolated from bone infections during 2000-2002. Narrow-spectrum antimicrobials such as vancomycin, quinupristin-dalfopristin and linezolid demonstrated good activity against Staphylococcus aureus and streptococci, and were active against 100% of isolates. However, Gram-negative species were also commonly isolated from these sites of infection. Later-generation cephalosporins, represented by ceftriaxone, cefotaxime and cefepime, exhibited a broad spectrum of activity including Enterobacteriaceae, streptococci and methicillin-susceptible S. aureus, but they were not active against methicillin-resistant S. aureus (MRSA) and showed variable activity against Pseudomonas aeruginosa. Using ceftazidime as a marker for extended spectrum beta-lactamase (ESBL) expression, less than 3% of Escherichia coli or Klebsiella pneumoniae expressed this phenotype. Based on current in vitro activity, the third-generation cephalosporins provide broad-spectrum coverage useful for the empirical therapy of suspected bone infections, especially for patients treated in the community or hospitalised with community-acquired infections.

[Diagnosis and follow-up management of postoperative bacterial osteitis]

Osteomyelitis is a term used to describe bone infection. As a complication, it can occur after open bone fracture and is associated with the implantation of foreign material. Acute disease after surgery starts after about 7 days to 4 weeks, and is characterized by a suppurative infection. Chronic infection sometimes manifests even years after surgery with a purulent sinus tract. Diagnosis is based on clinical signs, microbiological culture, histological evidence of the presence of granulocytes, and on radiological signs of osteomyelitis. However, it is sometimes difficult to distinguish between merely soft tissue involvement and osteomyelitis, especially in the presence of implanted material. Management includes a thoroughly surgical débridement and antibiotic treatment. Though frequently used, bacterial cultures of swabs of superficial wounds or fistulas are often misleading, whereas needle biopsy or surgical sampling with at least three tissue samples provides more reliable information. Because of the prolonged antibiotic treatment, it is mandatory for a successful outcome to culture the microorganism in order to determine antibiotic susceptibility. In addition to conventional radiological approaches, magnetic resonance imaging has become useful for the diagnosis of osteomyelitis. Despite significant progress in antibiotic therapy and orthopedic surgery, osteomyelitis remains difficult to treat and often relapses, even after years.

Outcomes of osteomyelitis among patients treated with outpatient parenteral antimicrobial therapy

PURPOSE

To examine the effects of diabetes, vascular disease, age, and antimicrobial therapy on clinical outcomes, including amputation rates, in patients with osteomyelitis treated in the outpatient setting.

METHODS

We performed a retrospective chart review of patients treated with intravenous antimicrobial therapy for osteomyelitis at an outpatient infectious diseases practice. All patients were followed for at least 6 months.

RESULTS

Four hundred and fifty-four patients qualified for inclusion, with follow-up information available for up to 10 years. One hundred and thirty-nine patients (31%) had recurrences and 27 (6%) had amputations. Of the recurrences, 108 (78%) occurred within 6 months and 132 (95%) within 1 year. In univariate analyses, peripheral vascular disease, diabetes, and the combination were all associated with the risk of recurrence; age (>70 years) was not. For osteomyelitis due to Staphylococcus aureus, the relative risk of recurrence, using a Cox regression model, was 0.8 for ceftriaxone (95% confidence interval [CI]: 0.4 to 1.5; P = 0.53), 1.1 for cefazolin (95% CI: 0.5 to 2.2; P = 0.80), and 2.5 for vancomycin (95% CI: 1.1 to 5.6; P = 0.04), as compared with the use of a penicillinase-resistant penicillin.

CONCLUSION

Diabetes and peripheral vascular disease are important factors in determining the prognosis of patients with osteomyelitis, but age is not. Almost all recurrences of osteomyelitis occur within 1 year. Recurrence rates with osteomyelitis associated with S. aureus appear to be higher with the use of vancomycin, whereas ceftriaxone and cefazolin appear to be similar to penicillinase-resistant penicillins.