Clinical outcomes of osteomyelitis patients infected with methicillin-resistant Staphylococcus aureus USA-300 strains

Methicillin-resistant Staphylococcus aureus (MRSA) USA-300 strains have emerged as an important cause of community-acquired infections. These strains have been recognized as an etiology of osteomyelitis but data on their incidence and outcomes are limited. We retrospectively studied the incidence and clinical outcomes of MRSA USA-300 osteomyelitis in patients at the University of Louisville Hospital and the Henry Ford Health System between January 2007 and March 2008. Pulsed-field gel electrophoresis was used to determine USA type. Clinical outcomes were defined as management success versus failure at 12 months. Chi-square tests, Fisher exact tests, and Mann-Whitney tests were used to compare patient characteristics on the basis of clinical outcomes and USA type. Of the 50 patients with MRSA osteomyelitis, 27 (54%) had the USA-300 strain. Clinical failure was identified in 22% (6/27) of the patients with MRSA USA-300 and in 30% (7/23) of the patients with MRSA non-USA-300 osteomyelitis (P = .509). Our results showed that MRSA USA-300 is a significant etiology of MRSA osteomyelitis. With current surgical and medical management, outcomes of patients with MRSA USA-300 osteomyelitis are similar to those of patients with MRSA non-USA-300 osteomyelitis.     

The outcome of therapy of osteomyelitis in children

Summary From 1987 to 1994, 28 children were admitted to our hospital with a haematogenous osteomyelitis. They were evaluated by chart review for history, clinical presentation, diagnostic work-up, treatment and outcome. The patients were considered to have an acute (n=12) or a chronic osteomyelitis (n=16). The mean age was 5.5 years and 5.9 years, respectively. Clinical symptoms such as local tenderness and swelling were present for 8 and 128 days, respectively. The mean temperature at admission was 38.4 and 37.3°C, respectively. The ESR, CRP and WBC were elevated in children with an acute osteomyelitis. In chronic osteomyelitis cases these findings were less elevated. On the X-rays in 6 and 16 children, respectively, abnormalities were visible. All children underwent a surgical procedure: a cortical window was made, pus was drained and necrotic tissue was excised. Positive cultures were obtained in 9 and 7 children, respectively. Subsequently, all patients were treated with i.v. and oral antibiotics. The mean duration of i.v. plus oral antimicrobial therapy was 20 plus 22 days for acute osteomyelitis and 20 Plus 25 days for chronic osteomyelitis. The mean duration of hospitalisation was 23 days in both groups. The mean follow-up was 3.7 years for patients with an acute osteomyelitis and 2.7 years for patients with a chronic osteomyelitis. After treatment, all but one patients were clinically well and the infection parameters had returned to normal values. Three patients had residual signs (ankylosis, decreased function). After surgical intervention it appears that six weeks of antibiotic therapy is sufficient to eradicate acute as well as chronic osteomyelitis in children.     

A comparison of short- and long-term intravenous antibiotic therapy in the postoperative management of adult osteomyelitis

The current standard recommendation for antibiotic therapy in the management of chronic osteomyelitis is intravenous treatment for six weeks. We have compared this regime with short-term intravenous therapy followed by oral dosage. A total of 93 patients, with chronic osteomyelitis, underwent single-stage, aggressive surgical debridement and appropriate soft-tissue coverage. Culture-specific intravenous antibiotics were given for five to seven days, followed by oral therapy for six weeks. During surgery, the scar, including the sinus track, was excised en bloc. We used a high-speed, saline-cooled burr to remove necrotic bone, and osseous laser Doppler flowmetry to ensure that the remaining bone was viable. Infected nonunions (Cierny stage-IV osteomyelitis) were stabilised by internal fixation. In 38 patients management of dead space required antibiotic-impregnated polymethylmethacrylate beads, which were exchanged for an autogenous bone graft at six weeks. Free-tissue transfer often facilitated soft-tissue coverage. These 93 patients were compared with 22 consecutive patients treated previously who had the same surgical management, but received culture-specific intravenous antibiotics for six weeks. Of the 93 patients, 80 healed without further intervention. Of the 31 Cierny-IV lesions, 27 healed without another operation, and four fractures required additional bone grafts. No more wound drainage was needed. Treatment was successful in 91% of patients, regardless of the organism involved. There was no difference in outcome in terms of these variables when the series were compared. We conclude that the long-term administration of intravenous antibiotics is not necessary to achieve a high rate of clinical resolution of wound drainage for adult patients with chronic osteomyelitis.     

Oral antimicrobial therapy for diabetic foot osteomyelitis

BACKGROUND: Osteomyelitis in the foot of a diabetic individual is a common complication of peripheral neuropathy, peripheral vascular disease, and infection. Operative facilities and home intravenous antibiotic therapy programs may not be available in remote or rural communities. Limited data are available regarding the treatment results of oral antimicrobial therapy, with or without limited office debridement for diabetic foot osteomyelitis. METHODS: This retrospective medical record review of 325 consecutive diabetic patients who were evaluated at a multidisciplinary foot clinic identified 94 (29%) patients with 117 episodes of osteomyelitis. The most common group of organisms isolated were aerobic gram-positive cocci, and the single most frequent organism was Staphylococcus aureus. A mean of 1.6 +/- 0.8 (range 1 to 4) pathogens were recovered per episode of osteomyelitis. Therapy was guided by culture results. There were 93 episodes of osteomyelitis (79 patients) that were treated with a mean of 3 +/- 1 oral antimicrobial agents (with or without an initial short course of intravenous antimicrobial agents) and had adequate followup to evaluate outcome of treatment; office treatment included bone debridement in 26 (28%) and toe amputation in nine (10%) of the 93 episodes (79 patients). RESULTS: Of the 93 episodes treated with oral antimicrobial agents (with or without an initial short course of intravenous antimicrobial agents), 75 (80.5%) episodes were put into remission. Mean duration of oral antimicrobial therapy was 40 +/- 30 weeks. Mean relapse-free followup duration was 50 +/- 50 weeks. CONCLUSIONS: Diabetic foot osteomyelitis was effectively managed with oral antimicrobial therapy with or without limited office debridement in most patients. This regimen may be especially useful in communities where infectious disease specialists and operative resources are limited.     

A critical review of the literature: part I: diagnosing osteomyelitis in patients with diabetes and foot ulcers.

Despite our best efforts, chronic wounds continue to confound us. Cases of patients with diabetes who have wounds are particularly perplexing and challenging to manage. The diagnosis and treatment of osteomyelitis in this population are of great interest to clinicians. Much of wound care is based on tradition and expert opinion. The current focus is on evidence-based practice. The purpose of this critical literature review is to determine the best evidence for diagnosing osteomyelitis as a basis for providing appropriate therapy to patients with diabetes and foot ulcers. Treatments vary greatly in terms of time, cost, and invasiveness depending on the accuracy of the diagnosis. The choice of oral versus parenteral antibiotics, the length of the treatment, and decisions about surgical intervention or aggressive debridement are based on correctly differentiating osteomyelitis from soft tissue infection, osteoarthropathy, and other conditions. It is difficult to differentiate soft tissue infection from bone infection in the patient with diabetes and neuropathic bone disease. The precision of available tools for diagnosing osteomyelitis in patients with diabetes and foot ulcers is widely debated. A gold standard as a reference test for clinical trials and treatment decisions has not been consistently used in published research studies. Without a reference test that is reliable and valid, the conclusions regarding effectiveness of diagnostic modalities and antibiotic treatment regimens are questionable.     

Oral rifampin plus azithromycin or clarithromycin to treat osteomyelitis in rabbits

A rabbit model for Staphylococcus aureus osteomyelitis was used to compare 28-day combination antibiotic therapy using oral rifampin (40 mg/kg, twice daily) plus oral azithromycin (50 mg/kg, once per day), oral clarithromycin (80 mg/kg, twice daily), or parenteral nafcillin (30 mg/kg, four times daily). The left tibial metaphysis of New Zealand White rabbits was infected with Staphylococcus aureus. Grades 3 to 4 osteomyelitis (according to the Cierny-Mader classification system) development in the rabbits was confirmed radiographically. After antibiotic therapy regimens of 28 days, all tibias from controls that were infected but left untreated (n = 10) revealed positive cultures for Staphylococcus aureus at a mean concentration of 2.8 x 10(4) colony forming units/g bone. The rifampin plus clarithromycin (n = 15) and rifampin plus azithromycin (n = 15) groups showed significantly lower percentages of positive Staphylococcus aureus infection (20% and 13.3%, respectively) and bacterial concentrations (3.5 x 10(1) and 1.75 x 10(1) colony forming units/g bone, respectively). The osteomyelitic tibias of the nafcillin plus rifampin treated group (n = 7) showed no detectable Staphylococcus aureus infection (significantly lower than controls). The differences observed for bone bacterial concentrations and sterilization percentages between the antibiotic treated groups were not statistically significant. Although fluoroquinolones (including ofloxacin and ciprofloxacin) are the agents usually prescribed with rifampin, increasing resistance has been observed. Although macrolides traditionally are not used in the treatment of osteomyelitis, the results of this study indicate that azithromycin and clarithromycin may be attractive partners for rifampin for the treatment of Staphylococcus aureus osteomyelitis in humans.     

Imaging in pelvic osteomyelitis: support for early magnetic resonance imaging

BACKGROUND: Children with pelvic osteomyelitis may present with symptoms that are nonspecific. Conventional imaging modalities including plain radiographs, ultrasound, technetium bone scan, and computed tomography rarely demonstrate pathology that is diagnostic of this condition. As a result, accurate diagnosis is often delayed, and children may undergo surgical diagnostic or therapeutic procedures that may be avoided. We report the radiographic and magnetic resonance imaging (MRI) findings in 23 children admitted with a suspected diagnosis of pelvic osteomyelitis. We are presenting imaging findings in children with suspected pelvic osteomyelitis with emphasis on MRI abnormalities and to propose an anatomical classification based on the patterns of pelvic involvement. METHODS: The medical records and imaging reports of all patients admitted to our institution with a history and physical examination suggestive of pelvic osteomyelitis between July 31, 1992, and March 10, 2003 were reviewed. Criteria were defined for the diagnosis of pelvic osteomyelitis based on criteria used by Farley et al in 1985. Specific attention was paid to the imaging strategies used and the influence of each radiographic method on the ultimate diagnosis. RESULTS: Abnormalities on the MRI included soft tissue inflammation and bone edema. These findings were bright on T2 and short inversion time Short T1 inversion recovery (STIR) images and enhanced after gadolinium administration. Five distinct patterns of pelvic involvement were observed, each corresponding to a cartilaginous epiphysis or apophysis. These were the sacroiliac joint, triradiate cartilage, pubic symphysis, ischium, and iliac apophysis. One patient had a noninfectious cause of presentation with a deep vein thrombosis, whereas another was diagnosed with Hodgkin lymphoma in addition to osteomyelitis of the ischium. CONCLUSIONS: Magnetic resonance imaging is a sensitive technique for evaluation of pyogenic infections involving the pelvis. In patients presenting with clinical findings and laboratory studies suggesting an infectious process, MRI with gadolinium enhancement should be performed as an early study. Magnetic resonance imaging is also effective in identifying other conditions that may resemble pelvic osteomyelitis.     

Oral ciprofloxacin compared with standard parenteral antibiotic therapy for chronic osteomyelitis in adults

A group of fourteen patients who had chronic osteomyelitis and were treated with oral ciprofloxacin was compared with a group of twelve patients of similar age who had chronic osteomyelitis and received standard parenteral antibiotic therapy consisting of nafcillin, clindamycin, and gentamicin, singly or in combination. The osteomyelitis was arrested at the end of therapy and on follow-up examination of eleven patients in the first group and ten in the second group. The average duration of antibiotic therapy (thirty-eight days) and follow-up (approximately thirty months) were about the same for both groups. Oral administration of ciprofloxacin was as effective and safe as parenteral therapy for the treatment of osteomyelitis in these adults.     

Bone and bone-muscle autoplasty in the treatment of chronic osteomyelitis

Osseous autoplasty of osteomyelitic cavities was used in 138 patients with different forms of chronic osteomyelitis. Complications were found in 8 patients. These patients had suppurations of the wound with sequestrations of osseous transplants.     

A critical review of the literature: part II: antibiotic treatment of osteomyelitis in patients with diabetes and foot ulcers.

The diagnosis and treatment of osteomyelitis in the diabetic patient with a foot ulcer presents a difficult challenge for WOC nurses. Treatments vary greatly in terms of time, cost, and invasiveness, as does the accuracy of the underlying diagnosis. For example, the choice of oral versus parenteral antibiotics, the length of therapy, and decisions about surgical intervention or aggressive debridement are based on accurate differentiation of osteomyelitis from soft tissue infection, osteoarthropathy, or other related conditions. This article is the second of a critical literature review designed to identify the best evidence for diagnosing and treating osteomyelitis in patients with diabetes. It focuses on the existing evidence base for antibiotic therapy.     

Oral Antibiotic Management of Acute Osteomyelitis of the Hand: Outcomes and Cost Comparison to Standard Intravenous Regimen

Background: Acute, direct inoculation osteomyelitis of the hand has traditionally been managed by intravenous antibiotics. With proven high levels of bone and joint penetration, specific oral antimicrobials may deliver clinical efficacy but at substantially lower cost. Methods: Sixty-nine adult patients with surgically proven acute, direct inoculation osteomyelitis of the hand were evaluated for clinical response on a 6-week postdebridement regimen of susceptibility-matched oral antibiotics. Inclusion required gross purulence and bone loss demonstrated at the initial debridement and radiographic evidence of bone loss. Excluded were 2 patients with extreme medical comorbidities. There were 53 men and 16 women with a mean age of 46 years. Mean follow-up was 16 weeks (±10). The cost model for the outpatient oral antibiotic treatment was intentionally maximized using Walgreen’s undiscounted cash price. The cost model for the traditional intravenous treatment regimen was intentionally minimized using the fully discounted Medicare fee schedule. Results: All patients achieved resolution of osteomyelitis by clinical and radiographic criteria. In addition, 7 patients underwent successful subsequent osteosynthesis procedures at the previously affected site without reactivation. The mean postdebridement direct cost of care per patient in the study cohort was $482.85, the cost of the antibiotic alone. The postdebridement direct cost of care per patient on a regimen of vancomycin 1.5 g every 12 hours via peripherally inserted central catheter line was $21 646.90. Conclusions: Acute, direct inoculation osteomyelitis of the hand can be successfully managed on oral antibiotic agents with substantial direct and indirect cost savings.     

Diagnosis and treatment of subacute osteomyelitis

BACKGROUND: Subacute osteomyelitis is well known for diagnostic difficulty because of insidious nonspecific clinical courses and radiographic appearances mimicking various benign and malignant conditions. There are controversies regarding the need for surgical debridement and/or postoperative antibiotic therapy. The purposes of this study are to report our experiences of treating subacute osteomyelitis and compare the results of systemic antibiotic therapy with local gentamicin-polymethylmethacrylate bead implantation after curettage of bone lesions. METHODS: Twenty-three patients referred to the orthopedic oncology service but later proven to have subacute osteomyelitis were studied. These patients were randomly assigned to two treatment protocols after surgery. Group I patients received standard parenteral antibiotics for 2 weeks followed by oral antibiotics for 4 weeks (10 patients). Group II patients received local gentamicin-polymethylmethacrylate bead implantation (13 patients). Hospital stay, medical cost, clinical course, and results were compared. RESULTS: All patients presented with diagnostic difficulties based on radiographic appearances. Penumbra sign on magnetic resonance imaging is helpful in differentiating subacute osteomyelitis from tumors. Hospital stay was significantly shorter (6.2 +/- 0.9 days vs. 16.4 +/- 1.1 days, p < 0.001), and medical cost was reduced (US $793 +/- 87 vs. US $1,268 +/- 98, p < 0.001) for group II patients. Both groups of patients responded well to the treatment regimens without recurrence of infection at a mean of 4.6 years after surgery. CONCLUSION: Differential diagnosis between subacute osteomyelitis and neoplasms requires careful clinical and radiographic evaluation. Penumbra sign on magnetic resonance imaging is helpful in differential diagnosis. Surgical debridement and local antibiotic bead implantation shortens hospital stay, reduces medical cost, provides satisfactory results of infection control, and prevents complications of long-term systemic antibiotic use.     

The treatment of chronic osteomyelitis: a 10 year audit.

Despite modern surgical techniques and advanced antimicrobial therapy, osteomyelitis remains a difficult and challenging problem. A 10 year audit study from 1990 to 2000 was carried out to assess the outcome of treatment of chronic osteomyelitis. A total of 41 patients with chronic osteomyelitis (26 male, 15 female with an age range of 10-76 years, mean 45.3 years) underwent extirpation and reconstruction with muscle interposition. The duration of osteomyelitis ranged from 1 to 69 years (mean 16.6 years) and many patients had undergone multiple attempted procedures prior to definitive treatment. Thirty-seven patients underwent free microvascular muscle transfer and four patients underwent local transposition muscle flaps. Two of the 41 patients developed recurrent sepsis at 12 months (4.4% recurrence rate). These were treated successfully with elevation of the flap and curettage of the remaining infection and debris and re-insetting of the flap. Only one patient in the series required a below knee amputation and this was as a result of persistent intractable bone pain rather than recurrence of the osteomyelitis.     

Chronic recurrent multifocal osteomyelitis: a distinct clinical entity

We reviewed the cases of five children with the diagnosis of chronic recurrent multifocal osteomyelitis (CRMO) and compared and contrasted them to 11 cases of subacute osteomyelitis. Significant differences were found between these two groups in the number of cases with positive biopsy cultures, number of clinical episodes, and number of bones involved. In CRMO, cultures are negative, and recurrent clinical episodes involve different bones at different times. The data indicate that CRMO is a distinct clinical entity, different from subacute osteomyelitis; it is a benign, self-limiting inflammatory disease of bone, and no chronic problems have occurred as a result of CRMO. Restraint in antibiotic treatment and in performing repeated biopsies is indicated in CRMO.     

Cranial melioidosis presenting as a mass lesion or osteomyelitis

OBJECT: Melioidosis is caused by Burkholderia pseudomallei and causes multiple abscesses in different organs of the body. Cranial melioidosis, although uncommon, is sometimes confused with tuberculosis and is therefore under-recognized. The authors report on 6 cases of cranial infections caused by Burkholderia pseudomallei, presenting as mass lesions or cranial osteomyelitis, and review the literature. METHODS: The authors performed a retrospective review of the records of patients with cranial melioidosis treated at their institution between 1998 and 2005 to determine the presentation, management, and outcome of patients with this infection. RESULTS: Of the 6 patients diagnosed with cranial melioidosis during this period, 4 had brain abscesses and 2 had cranial osteomyelitis. All patients were treated surgically, and a diagnosis was made on the basis of histopathological studies. All patients were started on antibiotic therapy following surgery and this was continued for 6 months. One patient died soon after stereotactic aspiration of a brain abscess, and the other 5 patients had good outcomes. CONCLUSIONS: Cranial melioidosis is probably more prevalent than has been previously reported. A high index of suspicion, early diagnosis, initiation of appropriate antibiotic therapy and treatment for an adequate period are essential for assuring good outcome in patients with cranial melioidosis. The authors recommend surgery followed by intravenous ceftazidime treatment for 6 weeks and oral cotrimoxazole for 6 months thereafter in patients with cranial melioidosis.     

What would pediatric infectious disease consultants recommend for management of culture-negative acute hematogenous osteomyelitis?

OBJECTIVE: To assess the opinion of pediatric infectious disease (PID) specialists regarding the management of culture-negative acute hematogenous osteomyelitis. METHODS: A questionnaire that included a hypothetical case scenario of a 4-year-old boy with culture-negative osteomyelitis was distributed via a Web-based system to PID specialists across the United States. RESULTS: Of 481 eligible participants surveyed, 147 (31%) responded. For initial therapy of osteomyelitis, 37% of respondents chose a beta-lactam, 24% chose clindamycin, 10% chose vancomycin as the sole therapy, and 29% chose a combination of these. The initial choice of antibiotics was correlated with the reported incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) in the institution (P < 0.01). In areas where the prevalence of CA-MRSA was intermediate (between 25% and 50%), the choice of antibiotics was more heterogeneous. For change from intravenous to oral therapy, approximately 70% of respondents would change to oral therapy sooner than 3 weeks depending on clinical, laboratory, and social factors. After significant clinical and laboratory (sedimentation rate and C-reactive protein) improvements, most respondents (69%) chose to treat for a total duration (intravenous and oral) of 3 to 4 weeks. CONCLUSIONS: This study illustrates that the empiric choice of antibiotics for treatment of acute hematogenous osteomyelitis was driven by the local prevalence of CA-MRSA. When the prevalence of CA-MRSA was intermediate, the recommendations for management of bone infections were more heterogeneous. Clinical trials are needed to compare the effect of different management strategies on outcome, side effects, and costs. LEVEL OF EVIDENCE: Level V.     

Group G streptococcus--a rare cause of osteomyelitis simulating bone tumour: a case report

We report a case of osteomyelitis of the proximal femur caused by Lancefield group G streptococcus in a 71-year-old otherwise healthy man. The organism has rarely been identified as the cause of osteomyelitis. The subacute nature of the symptoms and the radiological appearance of the femur in this patient mimic bone tumour. The patient was successfully treated with conservative methods, including a prolonged period of oral antibiotics. We stress the importance of histological and bacteriological evidence in avoiding misdiagnosing patients with equivocal clinical and radiological presentation.     

Primary calvarial cryptococcal osteomyelitis in a patient with idiopathic lymphopenia

Summary  An example of primary calvarial cryptococcal osteomyelitis in a patient with idiopathic lymphopenia is presented. The patient was a suboptimally immunocompetent host with an isolated skull involvement without any systemic infection. The Magnetic Resonance Imaging radiographic findings of the head are reviewed. The patient underwent surgical debridement of the lesion as well as receiving a course of oral antifungal medication. We discuss cryptococcal osteomyelitis and review the reports of cryptococcal disease and Idiopathic Lymphopenia. Correspondence: Amit Amit, Department of Neurosurgery, Frenchay Hospital, Bristol.     

Acute osteomyelitis in children: a review of 116 cases

We reviewed 116 cases of acute hematogenous osteomyelitis (AHO) (without septic joints) from 1979 to 1985 to establish current patterns of clinical presentation, modes of treatment, and success of therapy. We found that patients present early in the course of their disease, and many have no findings other than local tenderness and an elevated sedimentation rate. Sixty-four of the patients were treated nonoperatively. The average antibiotic treatment time was 2 weeks by intravenous (i.v.) administration followed by additional outpatient oral therapy for periods of up to 4 weeks. This treatment regimen applied specifically to acute osteomyelitis led to no known treatment failures.