Changing pattern of bone and joint infections due to Staphylococcus aureus: study of cases of bacteremia in Denmark, 1959-1988

Early switching from intravenous to oral antibiotic therapy in bone and joint infections associated with methicillin-susceptible Staphylococcus aureus bacteremia

OBJECTIVES

We aimed to evaluate the clinical outcomes of patients with bone and joint infection (BJI) associated with methicillin-susceptible Staphylococcus aureus bacteremia (MSSAB) treated with early oral switch to oral antibiotics (before day 14) versus later or no switch.

PATIENTS AND METHODS

We included all cases reported between January 2016 and December 2021 in the University Hospital of Reims.

RESULTS

Among 79 patients with BJI associated with MSSAB, 50.6% had an early switch to oral antibiotics, with median duration of intravenous antibiotics of 9 (IQR 6-11) days. The overall cure rate was 81% with follow-up of 6 months, and was 85.7% after excluding the 9 patients whose death was not related to BJI infection. Failure to control BJI did not differ between the two groups.

CONCLUSION

An early (before day 14) switch to oral antibiotics may be a safe therapeutic option in BJI associated with MSSAB.

Obesity in spontaneous spondylodiscitis: a relevant risk factor for severe disease courses

Spondylodiscitis is a serious and potentially life-threatening disease. Obesity is a risk factor for many infections, and its prevalence is increasing worldwide. Thus, the aim of this study was to describe characteristics of obese patients with spondylodiscitis and identify risk factors for a severe disease course in obese patients. Between December 2012 and June 2018, clinical records were screened for patients admitted for spondylodiscitis. The final analysis included 191 adult patients (mean age 64.6 ± 14.8 years). Patient data concerning demographics, comorbidities, surgical treatment, laboratory testing, and microbiological workup were analysed using an electronic database. Patients were grouped according to body mass index (BMI) as BMI ≥ 30 kg/m² or < 30 kg/m². Seventy-seven patients were classified as normal weight (BMI 18.5-24.9 kg/m²), 65 as preobese (BMI 25-29.9 kg/m²), and 49 as obese (BMI ≥ 30 kg/m²). Obese patients were younger, had a higher revision surgery rate, and showed higher rates of abscesses, neurological failure, and postoperative complications. A different bacterial spectrum dominated by staphylococci species was revealed (p = 0.019). Obese patients with diabetes mellitus had a significantly higher risk for spondylodiscitis (p = 0.002). The mortality rate was similar in both cohorts, as was the spondylodiscitis localisation. Obesity, especially when combined with diabetes mellitus, is associated with a higher proportion of Staphylococcus aureus infections and is a risk factor for a severe course of spondylodiscitis, including higher revision rates and sepsis, especially in younger patients.

Health Care Utilization and Payments of Postoperative and Drug Abuse-Related Spinal Infections

STUDY DESIGN

Retrospective analysis of data extracted from the MarketScan database (2000-2016) using International Classification of Diseases (ICD)-9, ICD-10, and Current Procedural Terminology-4 codes.

OBJECTIVE

Evaluate the economic costs and health care utilization associated with spine infections.

SUMMARY OF BACKGROUND DATA

Spinal infections (SI) are associated with significant morbidity and mortality. A recent spike in SI is attributed to the drug abuse epidemic. Management of SI represents a large burden on the health care system.

METHODS

We assessed payments and outcomes at the index hospitalization, 1-, 3-, 6-, and 12-month follow up. Outcomes assessed included length of stay, complications, operation rates, and health care utilization. Outcomes were compared between cohorts with spinal infections: (1) with prior surgery, (2) drug abuse, and (3) without previous exposure to surgery or drug abuse, denoted as control.

RESULTS

We identified 43,972 patients; 15.6% (N = 6847) of patients underwent prior surgery, 3.8% (N = 1,668) were previously expose to drug abuse while 80.6% fell into the control group. Both the postsurgical and drug abuse groups longer hospital stay compared with the control cohort (5 d vs. 4 d, P < 0.0001). Exposure to IV drug abuse was associated with increased risk of complications compared with the control group (43% vs. 38%, P < 0.0001). Payments at 1-month follow-up were significantly (P < 0.0001) higher among the postsurgical group compared with both groups. However, at 12-months follow-up, payments were significantly (P < 0.0001) higher in the drug abuse group compared with both groups. Only postsurgical infections were associated with higher number of surgical interventions both at presentation and 1 year follow up.

CONCLUSION

SI following surgery or IV drug abuse are associated with higher payments, complication rates, and longer hospital stays. Drug abuse related SI are associated with the highest complication rates, readmissions, and overall payments at 1 year of follow up despite the lower rate of surgical interventions.

LEVEL OF EVIDENCE

3.

Progression of Infection after Surgical CT Navigation-Assisted Aspiration Biopsy of a Vertebral Abscess

Background Context. Computed tomography- (CT-) guided fine-needle aspiration biopsy of the vertebral body is an important tool in the diagnostic evaluation of vertebral osteomyelitis. The procedure is considered simple to perform and it is considered a safe procedure with few complications. Purpose. The purpose of this study was to describe an unusual complication due to a CT-guided fine-needle aspiration biopsy of the vertebral body of L3, to better understand the relationship between surgical procedure and complication, and to reflect on how to avoid it. Study Design/Setting. Case report and literature review. Methods. The medical records, laboratory findings, and radiographic imaging studies of an 11-year-old boy, with an unusual complication due to a CT-guided fine-needle aspiration biopsy of the vertebral body of L3, were reviewed. Results. We report a case of vertebral osteomyelitis of L3 caused by methicillin-sensitive Staphylococcus aureus (MSSA). Following a computed tomography-guided aspiration biopsy of the vertebral body of L3, vertebral osteomyelitis rapidly progressed into the vertebral body of L4 as well as the L3-L4 disk. Conclusions. Based on the present case, one should consider that a CT-guided fine-needle aspiration biopsy of the vertebral body may be complicated by a progression of a vertebral osteomyelitis into both the intervertebral disk and also the adjacent vertebral body.

Staphylococcus aureus infections: epidemiology, pathophysiology, clinical manifestations, and management

Staphylococcus aureus is a major human pathogen that causes a wide range of clinical infections. It is a leading cause of bacteremia and infective endocarditis as well as osteoarticular, skin and soft tissue, pleuropulmonary, and device-related infections. This review comprehensively covers the epidemiology, pathophysiology, clinical manifestations, and management of each of these clinical entities. The past 2 decades have witnessed two clear shifts in the epidemiology of S. aureus infections: first, a growing number of health care-associated infections, particularly seen in infective endocarditis and prosthetic device infections, and second, an epidemic of community-associated skin and soft tissue infections driven by strains with certain virulence factors and resistance to β-lactam antibiotics. In reviewing the literature to support management strategies for these clinical manifestations, we also highlight the paucity of high-quality evidence for many key clinical questions.

Infectious spondylodiscitis: has there been any evolution in the diagnostic and treatment outcomes?

Objective: To evaluate the clinical and radiological results of treatment of patients with spondylodiscitis. Methods: Imaging exams used in this study were plain radiographs and magnetic resonance imaging of the spine. Results: Data from 33 patients, 10 (30.3%) females and 23 (69.7%) males were evaluated. The average time to diagnosis was four months and 28 days (SD &#177; 1 month and 28 days) and 19 patients (57.5%) presented neurological deficit. Surgical treatment was performed in 22 patients (66.6%) and three patients (9.1%) had complications from the surgery. Conclusions: Despite technological advances in complementary exams, early diagnosis of spondylodiscitis remains a challenge. However, drug treatment associated with surgery shows good results.

Rapid sensitive molecular diagnosis of pyogenic spinal infections using methicillin-resistant Staphylococcus-specific polymerase chain reaction and 16S ribosomal RNA gene-based universal polymerase chain reaction

BACKGROUND CONTEXT

Rapid diagnosis and accurate detection of etiological agents in pyogenic spinal infection (PSI) patients are important.

PURPOSE

The purpose of this study was to evaluate the clinical usefulness of methicillin-resistant Staphylococcus-specific polymerase chain reaction (MRS-PCR) and broad-range universal PCR (U-PCR) for diagnosing PSI.

STUDY DESIGN

A prospective diagnostic study.

PATIENTS

Thirty-two clinically suspect PSI patients and six control patients who underwent computerized tomography-guided biopsy and/or surgical treatment were enrolled.

METHODS

Tissue samples were examined by microbiological culture, histopathology, and real-time PCR (MRS-PCR and U-PCR). The diagnostic accuracy of real-time PCR was analyzed based on the definitive diagnosis of infection, defined as a positive result from microbiological culture or histopathology.

RESULTS

All six control subjects were negative for PSI for all analyses. Twelve clinically suspect PSI subjects received definitive diagnoses (PSI group). The non-PSI group consisted of six control subjects plus the remaining 20 patients from the PSI clinically suspect group. MRS-PCR results were positive for all MRS-cultured PSI subjects. U-PCR was positive for all subjects in the PSI group with one discrepancy between real-time PCR and microbiological culture results in differentiation between gram-positive and gram-negative bacteria. In the non-PSI group, MRS-PCR and U-PCR were positive in three and seven cases, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of MRS-PCR for diagnosing MRS infection were 1.00, 0.91, 0.57, and 1.00, respectively; those for the diagnosis of bacterial infection with U-PCR were 1.00, 0.73, 0.63, and 1.00, respectively.

CONCLUSION

Identification of MRS infection and ability to differentiate between gram-positive and gram-negative bacteria is rapidly achieved using MRS-PCR and U-PCR. Real-time PCR provides a sensitive molecular diagnosis of PSI and may contribute to antibiotic selection.

Early surgical intervention for spinal infection in patients with malignancy requiring chemotherapy: report of two cases and review of the literature

Advances in chemotherapy for various malignancies have contributed to the increased life expectancy of patients. If such a patient has a concurrent infection, his/her oncologist would hesitate to perform prompt chemotherapy owing to the risk of inducing sepsis. Therefore, the treatment of infection would have priority over initiating chemotherapy for the malignancy. We present a 69-year-old female with malignant lymphoma requiring prompt chemotherapy who also demonstrated spinal infection with Mycobacterium tuberculosis and a 66-year-old male with esophageal cancer who also demonstrated spinal infection with Staphylococcus aureus. Anterior debridement and interbody fusion were performed for both patients. One patient died of malignant lymphoma 4 years after surgery, and the other is still alive and has remained disease-free 4 years after surgery. Saving the life of a patient with malignancy would be difficult without prompt chemotherapy. Conservative treatment for spinal infection requires prolonged antibiotic treatment, and there is no guarantee that the spinal infection would be controlled only with antibiotics. Therefore, early surgical intervention would be an alternative option under such a condition.

Management of infectious discitis. Outcome in one hundred and eight patients in a university hospital

PURPOSE

The optimal management of pyogenic discitis is not agreed on. We conducted a retrospective, cross-sectional, observational study in which all patients with discitis who attended Hospital San Carlos Madrid from January 1999 to January 2009 were included.

METHODS

We identified 108 consecutive adult patients with infectious discitis. There were 49 men and 59 women with an average age of 67,5 (+/- 16,89) years in the study group. Mean follow-up interval was 6,06 (12,5-2) years. 78 patients had spontaneous discitis and 30 patients had postoperative discitis. Inclusion criteria for the review were illness compatible with vertebral infection and / or evidence of spinal involvement on magnetic resonance imaging (MRI).

RESULTS

In 56 percutaneous discal biopsy (52% patients) were positive in 28 cases. A single disc was infected in 100 patients. The segments involved were the cervical spine in four, the thoracic spine in 38 and the lumbar spine in 66. One or more comorbid diseases were present in 73 (68%) of 108 patients. Diabetes mellitus was the most common disease. Comorbid disease was rapidly fatal in four patients, ultimately fatal in seven patients, and nonfatal or not present in 97 patients (90 %).

CONCLUSION

Early diagnosis is a major challenge. Heightened awareness and the prompt use of MRI are necessary to avoid diagnostic delay. Prolonged antimicrobial therapy and the judicious application of timely surgical intervention are essential for an optimal outcome.

Clinical features of spinal infection in individuals older than eighty years

PURPOSE

Japan has one of the most rapidly increasing numbers of elderly individuals; therefore, future trends in spinal infections in the elderly in other countries may be predicted by studying such characteristics in Japan. The purposes of this study were to identify whether the incidence of spinal infection in individuals more than 80 years old is increasing and to define its clinical characteristics.

METHODS

We retrospectively reviewed the medical records of 98 patients treated in our hospital for spinal infection between 1999 and 2008. Patients were divided into two groups: those admitted to our hospital during the initial five year period, and those admitted during the latter five year period. We evaluated changes in the percentage of individuals over the age of 80 years. To define the clinical characteristics of spinal infection, patients were also divided into another set of two groups: those over 80 years and those around the age of 80 years.

RESULTS

The percentage of patients over 80 years with spinal infection was significantly increasing. There was no significant difference in the gender distribution, prevalence of immunocompromised hosts, common involved levels, or mortality rate between the two age groups. The pathogenic organism was isolated in 78.6%, and of these, the rate of methicillin-resistant Staphylococcus aureus or epidermidis was 2.46 times higher in the elderly group than in the younger group.

CONCLUSIONS

The number of patients over 80 years with spinal infection is expected to rapidly increase in aging societies. This advanced age group is more susceptible to infection with drug-resistant organisms, which makes infection management more difficult.

Challenges in Periprosthetic Knee-Joint Infection

The number of knee arthroplasty procedures is growing and projected to further increase. The risk for periprosthetic joint infection (PJI) is estimated to be low (<1%). However, considering the increasing number of total knee arthroplasty, the increasing number of patients with multiple comorbidities, and the lifelong risk for acquiring hematogenous infection, the total number of PJI will further increase. Despite existing treatment concepts for PJI of the knee, there are still questions to solve, such as type of debridement surgery in case of implant retention, the role of a spacer from a microbiological perspective, and the optimal duration of antimicrobial therapy. In this review, these questions will be analyzed according to the available literature and the experience of the authors. Moreover, we review the most recent data on infection, risk factors, and microbiology of PJI.

Periprosthetic joint infection following Staphylococcus aureus bacteremia

OBJECTIVES

The incidence of haematogenous periprosthetic joint infections (PJI) among patients with remote infections has been reported to be less than 1%. This incidence may be much higher in cases after documented Staphylococcus aureus bacteremia (SAB). We evaluated the incidence of haematogenous PJI following SAB in patients with previously uninfected arthroplasties.

METHODS

A retrospective analysis of our cohort including patients with SAB and prosthetic joints at the Basel University Medical Clinic Liestal from 1998 to 2008.

RESULTS

We identified 31 patients with 45 uninfected prosthetic joints in situ at the time of SAB. In 12 patients (39%) and 13 arthroplasties (29%), SAB caused PJI. In comparison to nosocomial SAB, infections occurred only in cases with community-acquired SAB (p=0.002). PJI was diagnosed within a median time of 2.5 days (IQR 1-3.5) after admission. The comparison between patients with and without PJI revealed no significant difference in gender, age, comorbidities and number of prostheses per patient and age of the prosthesis.

CONCLUSIONS

The rate of PJI after SAB is high, ranging from 30% to 40%, and clearly higher than rates reported for bacteremia with other pathogens. PJIs were observed in community-onset bacteremia, in which there is a typically delay from symptoms to antimicrobial treatment.

Bacteraemia and subsequent vertebral osteomyelitis: a retrospective review of 125 patients

BACKGROUND

Vertebral osteomyelitis (VO) is associated with considerable morbidity and its incidence seems to be increasing. Haematogenous spread is an important aetiological factor.

AIM

The objective was to describe a series of patients with VO and to search for a relationship between preceding bacteraemia and subsequent VO with the same pathogen.

DESIGN AND METHODS

A retrospective study of all treated cases of VO in a tertiary hospital over a 10-year period.

RESULTS

There were 129 cases of VO (involving 125 patients) that received antimicrobial treatment. Eighty-three (66%) were male and the mean age was 59.5 years (range 1 month to 87 years). The vertebral level involved was lumbar in 66 (53%) cases and thoracic in 35 (28%) cases. Seventy-four cases (59%) had a microbiologically confirmed aetiology. The diagnostic yield from procedures was 46 and 36% from blood culture and bone biopsy, respectively. Staphylococcus aureus was the most common pathogen [38 of 74 (51%) cases]. Nine of 38 (24%) cases of Staphylococcus aureus VO had a preceding bacteraemia with the same pathogen in the previous year.

CONCLUSION

Staphylococcus aureus is an important pathogen causing bacteraemia with the ability to cause metastatic complications including VO. The high proportion of cases developing VO following a documented bacteraemia, sometimes many months previously, reinforce the importance of adequate aggressive treatment for bacteraemia. VO must be considered in all patients presenting with back pain up to a year after bacteraemia. Previous bacteraemias with relevant pathogens can help guide antibiotic treatment at presentation of VO and if biopsy cannot be obtained.

Spondylodiscitis: update on diagnosis and management

Spondylodiscitis, a term encompassing vertebral osteomyelitis, spondylitis and discitis, is the main manifestation of haematogenous osteomyelitis in patients aged over 50 years. Staphylococcus aureus is the predominant pathogen, accounting for about half of non-tuberculous cases. Diagnosis is difficult and often delayed or missed due to the rarity of the disease and the high frequency of low back pain in the general population. In this review of the published literature, we found no randomized trials on treatment and studies were too heterogeneous to allow comparison. Improvements in surgical and radiological techniques and the discovery of antimicrobial therapy have transformed the outlook for patients with this condition, but morbidity remains significant. Randomized trials are needed to assess optimal treatment duration, route of administration, and the role of combination therapy and newer agents.

Arthropathic and amyloidogenic Enterococcus faecalis infections in brown layers: A study on infection routes

Intravenous, intra-articular and intraperitoneal inoculation of 6-week-old brown-layer pullets with an arthropathic and amyloidogenic strain of Enterococcus faecalis resulted in amyloid arthropathy, while intramuscular, oral and intratracheal inoculation did not. Oral inoculation of 1-day-old chickens did not cause any pathology. However, intramuscular inoculation with 10⁶ colony forming units resulted in severe growth retardation and arthritis in 60% of the birds, and amyloid arthropathy in approximately 40%. In egg transmission studies, neither egg dipping nor inoculation of the air chamber with E. faecalis reproduced the condition, although a few chicks became septicaemic. Yolk sac inoculation of 6-day-old embryos caused embryonic death within 2 days. In contrast, egg albumen inoculation with E. faecalis led to arthritis in one of six of the progeny, indicating the possibility that vertical transmission of E. faecalis by the oviductal route could lead to arthritis. The presence of antibodies to E. faecalis was confirmed by enzyme-linked immunosorbent assay in 14/15 of experimental birds that had developed arthritis.

The clinical significance of concurrent Staphylococcus aureus bacteriuria in patients with S. aureus bacteremia

OBJECTIVE

To investigate the clinical significance of Staphylococcus aureus bacteriuria (SABU) in patients with S. aureus bacteremia (SAB).

METHODS

We reviewed clinical data for 203 patients with SAB from January 2006 to July 2007 in a tertiary care hospital. In all patients, blood and urine cultures were performed concurrently. Among these cases, we compared clinical data between patients with and without SABU. To rule out mere colonization of S. aureus through indwelling urinary catheters (IDUC), we excluded patients using IDUC and then repeated the analyses.

RESULTS

Concurrent SABU was observed in 31 of 203 patients (15.3%). In patients without an IDUC, 25 of 128 (19.5%) were positive for SABU. Concurrent SABU was associated with methicillin-susceptible, community-onset SAB, urinary tract obstruction/surgery, urinary tract infection, and vertebral osteomyelitis in patients with SAB. In patients without an IDUC, methicillin-susceptible SAB, urinary tract obstruction, urinary tract infection, and vertebral osteomyelitis were associated with concurrent SABU. Finally, concurrent SABU was not associated with the severity and fatality of SAB.

CONCLUSION

We found that SABU was not a result of colonization via IDUC, but instead is a frequent concomitant of SAB. In septic conditions, especially without IDUC, SABU may indicate SAB with foci of infection in the urinary tract or the vertebral column.

Recent trends in spinal infections: retrospective analysis of patients treated during the past 50 years

We retrospectively reviewed the medical charts of 210 consecutive patients treated for spinal infection in Tottori University Hospital in Japan between 1956 and 2005. Until 1995, spinal infection was under control in this series; however, during the last decade, it has been on the rise. Male predominance had been gradually progressing, and 69% of the patients were male during the last decade. Patients with spinal infection were aging, and the ratio of immunocompromised hosts dramatically increased to 53%. Until 1995, the percentage of patients with tuberculous spondylitis had been declining; however, the incidence has been on the rise during the last ten years. The organism was detected in 64% of patients treated between 1996 and 2005, of which Staphylococcus aureus was detected in 49%. Moreover, methicillin-resistant S. aureus was detected in 61% of patients with S. aureus. There were no immigrants or cases with human immunodeficiency virus in this series.

The use of polymerase chain reaction for the detection and speciation of bacterial bone and joint infection in children

We evaluated 36 consecutive patients presenting with signs and symptoms of bacterial bone and joint infection and 10 control patients using bacterial cultures of blood and the presumed site of infection compared with polymerase chain reaction (PCR) techniques using a universal primer and restriction endonuclease digestion. Of the 28 patients with definitive clinical and/or laboratory evidence of bacterial infection, 16 patients had positive bacterial cultures and 12 were PCR-positive. Twenty of 28 patients were either PCR- or culture-positive. Nine of the 16 subjects who had culture-positive samples also had PCR-positive samples (8 positive for the same organism and 1 with 2 organisms identified by culture, but only a single organism by PCR. Six culture positive patients were PCR-negative. Of the 12 patients who were culture-negative, 4 had bacterial genomic material present indicating infection. We conclude that current PCR methods are not superior to standard bacterial culture methods when applied to children with presumed bone or joint infections, but that PCR may complement existing microbiologic cultures for detection of bone and joint infections in children.

Frequency and risk factors for deep focus of infection in children with Staphylococcus aureus bacteremia

BACKGROUND

Staphylococcus aureus bacteremia (SAB) in children may be associated with development of deep-seated foci of infection, often prompting extensive diagnostic testing. The objective of this study was to establish the frequency and risk factors for deep foci of infection from SAB in pediatric patients.

METHODS

Medical charts of all children admitted with SAB to a tertiary-care center from January 1992 to June 2006 were reviewed. Study outcome was the presence of a deep focus of infection as documented by positive echocardiogram, bone imaging or abdominal imaging.

RESULTS

We studied 298 children, of whom 190 (64%) had echocardiograms, 116 (39%) had abdominal imaging, and 103 (35%) had bone imaging. Forty-seven subjects (16%) had symptoms of a deep focus of infection on discovery of SAB, which then was confirmed by 1 of the 3 tests. Eleven (3.7%) additional subjects had a clinically unsuspected deep focus identified before discharge. All children with an unsuspected deep focus of infection had either an underlying medical condition that potentially obscured the diagnosis or a central venous catheter. More than 1 day of positive blood cultures was associated with an unsuspected deep-seated infection (P < 0.01). Endocarditis was uncommon (2.7%), and occurred only in children with known congenital heart disease or with a central catheter.

CONCLUSIONS

Deep-seated infections from SAB in children are most often clinically apparent at discovery of bacteremia. Unsuspected deep-seated infection is uncommon and confined to specific hosts. Routine diagnostic imaging is not indicated in all children with SAB.

Osteomyelitis and the role of biofilms in chronic infection

Understanding the mechanisms implicated in the initial attachment, development, and maturation of a biofilm phenotype are of tremendous importance for their effect on the medical, industrial, and public health arenas. This review explores the current understanding of the nature of biofilms and the impact that molecular interactions between the bacteria themselves, as well as between bacteria and the host, may have on biofilm development and phenotype using the nonmotile Gram-positive coccus, Staphylococcus aureus, as an example.

MICU: Unusual Cause of Low Back Pain

A sixty years old patient, known case of chronic renal failure on regular hemodialysis through long term intravascular catheter was admitted with fever. Blood culture revealed staphylococcus aureus bacteremia (MSSA).

Hematogenous methicillin-resistant Staphylococcus aureus spondylodiscitis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To determine relevant demographics, clinical presentations, and outcomes of this condition.

SUMMARY OF BACKGROUND DATA

This is the first study looking specifically at methicillin-resistant Staphylococcus Aureus (MRSA) spondylodiscitis.

METHODS

We performed a retrospective review of patients presenting between 2000 and 2005.

RESULTS

Thirteen cases were identified. The mean age was 65 years; 85% were male. All cases presented with back pain, spinal tenderness, and systemic upset. Neurologic deficit was present initially in 39%, and 8% developed neurologic deterioration during treatment. The thoracic spine (53%) was most commonly affected, followed by the lumbar (33%), thoracolumbar junction (7%), and cervical spine (7%); 16% of cases were multilevel. The white cell count, erythrocyte sedimentation rate and C-reactive protein were elevated in all cases with means of 17.3 x 10(-9)/L, 102 mm/h, and 236 mg/L, respectively. Radiologic diagnosis was established with MRI in all cases. The most common risk factors were diabetes mellitus (62%), malnourishment (54%), cirrhosis (31%), end-stage renal failure (15%), and intravenous drug use (15%). Multiple risk factors were present in 76% of cases, and only 15% had no identifiable risk factors. The main sources of sepsis were intravenous catheters (23%), urinary tract (15%), and intravenous drug use (15%). Treatment consisted of intravenous vancomycin monotherapy for a mean period of 4 weeks followed by oral combination or monotherapy antimicrobials for a mean period of 8 weeks. Operative intervention was required in 38% of cases. At 6 months, 54% of cases were clinically free of infection, 38% had died, and 8% required ongoing treatment. Neurologic deficit was present in 50% of survivors. At 1 year, 29% of survivors had MRSA bacteremia and spondylodiscitis recurrence.

CONCLUSION

This is a devastating condition with high mortality and morbidity.

Adult osteomyelitis

Adult osteomyelitis remains difficult to treat, with considerable morbidity and costs to the health care system. Bacteria reach bone through the bloodstream, from a contiguous focus of infection, from penetrating trauma, or from operative intervention. Bone necrosis begins early, limiting the possibility of eradicating the pathogens, and leading to a chronic condition. Appropriate treatment includes culture-directed antibiotic therapy and operative debridement of all necrotic bone and soft tissue. Treatment often involves a combination of antibiotics. Operative treatment is often staged and includes debridement, dead space management, soft tissue coverage, restoration of blood supply, and stabilization. Clinicians and patients must share a clear understanding of the goals of treatment and the difficulties that may persist after the initial course of therapy or surgical intervention. Chronic pain and recurrence of infection still remain possible even when the acute symptoms of adult osteomyelitis have resolved.

[Multistep surgery for spondylosyndesis. Treatment concept of destructive spondylodiscitis in patients with reduced general condition]

OBJECTIVE

Retrospective assessment of multistage surgery in the treatment of progressive spondylodiscitis in patients with critical physical status.

PATIENTS

A total of 34 patients (mean age 58.6 years) with 37 progressive spondylodiscitis foci and destruction of one to three vertebral segments (1.9 mean) were recorded within an 8-year period. Time between first complaints and operative treatment was 3 months (mean). Preoperative health status was critically reduced in 11 patients (ASA IV) and poor general condition (ASA III) was seen in 23 patients when vital indication was seen preoperatively. Considerable systemic disease (n=31), further infection focus (n=18), and nosocomial trauma (n=5) were causally related. Spondylodiscitis was seen more frequently in the lumbar (n=20) and thoracolumbar than in the thoracic (n=10) and cervical spine (n=1). Staphylococcus aureus was detectable from operative specimens and hemoculture in 15 cases, MRSA in 6 of these.

METHODS

In cases of monosegmentary involvement (n=7) ventral debridement, biopsy, and application of antibiotic chains were followed by autologous interbody bone grafting in a second stage operation. In 29 cases with destruction of two (n=27) and three (n=3) segments, posterior instrumentation including laminectomy in 4 patients was completed by anterior debridement and application of antibiotic chains during a first surgical intervention. After stabilization of physical condition and having reached a macroscopically indisputable implant bed, the ventral fusion with autologous interbody bone grafting or cage in combination with a plate or internal fixation system was performed as the last of several surgical steps.

RESULTS

No case of perioperative mortality was observed. Intensive care continued 9.1 days and hospitalization 49.5 days (mean). During a 37.6-month follow-up two late recurrences were observed.

CONCLUSION

A multistep surgical procedure under protection of dorsal instrumentation can limit perioperative mortality in patients in critical general condition by avoiding an extended one stage dorsoventral spondylodesis. After eradication of further infection foci and stabilization of physical condition, ventral instrumentation is completed under elective conditions.

Hematogenous Vertebral Osteomyelitis Due to Staphylococcus aureus in the Adult: Clinical Features and Therapeutic Outcomes

OBJECTIVE

Staphylococcus aureus is the most common cause of hematogenous vertebral osteomyelitis in adults. To better define clinical features and therapeutic outcomes, the charts of 40 adult patients with S aureus hematogenous vertebral osteomyelitis were retrospectively reviewed.

METHODS

Retrospective chart review using standardized data collection form.

RESULTS

S aureus hematogenous vertebral osteomyelitis commonly occurred in the settings of recent invasive procedures (55% of patients), insulin use (28%), and hemodialysis (20%). Ten percent of patients had S aureus bacteremia or vascular catheter infection within the preceding 6 months. Median time from first symptom to diagnosis was 51.3 days. A portal of entry for S aureus was identified in 13 patients (32.5%); intravenous catheters were the likely origin in 9 of those 13 patients. Concurrent endocarditis was present in 4 patients. Forty-eight percent of patients had neurologic abnormalities and 60% of patients had an epidural, paraspinous, or psoas abscess demonstrated by neuroimaging. S aureus was isolated through fine-needle aspiration in 17 of 23 patients (74%) and from blood cultures in 23 of 34 patients (68%). Infection was due to methicillin-susceptible S aureus in 67.5% of patients. All patients received intravenous antibiotics for a mean duration of 58.6 days; 36 of 40 (90%) also received concomitant rifampin. Twenty-seven percent and 12.5% of patients underwent surgical debridement and CT-guided drainage of abscesses, respectively. After intravenous therapy, 19 of 30 eligible patients received oral continuation treatment. The mean duration of total antibiotic therapy was 142.2 days.

CONCLUSIONS

Cure of infection was achieved in 83% (24/29) of evaluable patients, but 50% of those achieving cure still had infection-related sequelae. Intravenous antibiotic therapy for at least 8 weeks was the only clinical factor associated with cure (P = 0.05, two-tailed Fisher exact test).

Importance of focus identification in the treatment of Staphylococcus aureus bacteraemia

Staphylococcus aureus bacteraemia increases in frequency, and it is still a life-threatening disease. In recent years, some interesting studies such as the need for focus identification and the focus eradication have been performed. The aim of this review is to present an up-to-date assessment of the current challenges in the management of S. aureus bacteraemia in order to improve the outcome.

Staphylococcus aureus bacteraemia in children: a 5-year retrospective review

OBJECTIVE

The clinical presentation of Staphyloccocus aureus bacteraemia has been well described in adults, but there is a paucity of published data on the presentation of S. aureus bacteraemia in children. This review sought to compare the presentation of S. aureus in children with that of adults.

METHODS

We conducted a 5-year retrospective chart review of S. aureus bacteraemia at the Royal Alexandra Hospital for Children between 1994 and 1998.

RESULTS

Of the 140 episodes of S. aureus bacteraemia, 53% were community acquired and 47% nosocomially acquired. The clinical presentation of S. aureus bacteraemia in the children in the present study differed significantly from published studies of adult patients. Of children with community-acquired bacteraemia without pre-existing medical conditions, 59% had a bone or joint infection, which is higher than adult series. Endocarditis has been associated with up to 30% of community-acquired bacteraemia in adults but was much less frequent (1.4%) in the present study. Despite the infrequent use of empiric antibiotic therapy (34% of episodes), the case fatality rate (1.4%) was significantly lower than the published literature relating to adults (11-32%).

CONCLUSION

The present study highlights the differences between S. aureus bacteraemia in adults and children.

Staphylococcus aureus infections and antibiotic resistance in older adults

The prevalence of infection with Staphylococcus aureus among older adults is unknown, but clinical syndromes caused by this organism are common. Bacteremia, pneumonia, endocarditis, and bone and joint infections are encountered with relative frequency in this population, and the clinical presentation may be atypical. Underlying disease and functional debility, rather than age itself, predispose the older adult to staphylococcal carriage and infection. Infections with methicillin-resistant strains of S. aureus are acquired primarily in hospital, rather than in nursing homes or in the community. Lack of clinical suspicion for S. aureus infection and delays in appropriate therapy can be fatal. Staphylococcal infection should be considered for an older adult with risk factors for staphylococcal carriage, comorbid illness, debility, and history of recent hospitalization or nursing home stay. Choices regarding empirical therapy should be made on the basis of knowledge of local antibiotic susceptibility patterns.

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.

Acute bacterial arthritis caused by group C streptococci

OBJECTIVES

To summarize the characteristics of and clinical experience with joint infection by group C streptococcus.

METHODS

Two new cases of acute bacterial arthritis due to group C streptococci are reported, and a MEDLINE search was performed, which located 22 additional cases.

RESULTS

Mean age (+/- standard deviation) of all 24 patients was 46 +/- 25 years, and most patients were men (75%). The species most frequently identified was Streptococcus equisimilis (12 cases). Eight patients (33%) had a general risk factor for infection, and the same percentage had some type of arthropathy. Only 3 patients had previous contact with animals. The infection was polyarticular in a third of cases, and the joint most frequently involved was the knee. The majority of patients showed a good response to the treatment with intravenous penicillin. However, 3 patients had functional sequelae, 2 more had residual radiological lesions, and 3 died.

CONCLUSIONS

Acute bacterial arthritis due to group C streptococci is a serious but uncommon entity that can affect patients without risk factors. Rapid diagnosis and treatment may improve the outcome. Semin Arthritis Rheum 31:43-51.

Bone and joint infections in the elderly: practical treatment guidelines

Two types of haematogenous osteomyelitis that are seen in the elderly are vertebral and long bone osteomyelitis. Osteomyelitis secondary to contiguous foci of infection can occur in older adults without vascular insufficiency (secondary to pressure ulcers) or with vascular insufficiency due to diabetes mellitus or peripheral vascular disease from atherosclerosis. Most cases of osteomyelitis can be reasonably treated with adequate drainage, thorough debridement, obliteration of dead space, wound protection, and antimicrobial therapy. Patients are initially given a broad spectrum antimicrobial that is changed to specific antimicrobial therapy based on meticulous bone cultures taken at debridement surgery or from deep bone biopsies. Surgical management is often required in the treatment of osteomyelitis and includes adequate drainage, extensive debridement of all necrotic tissue, obliteration of dead spaces, stabilisation, adequate soft tissue coverage, and restoration of an effective blood supply. Bone repair and bone mineral density may be significantly retarded and may be corrected by eliminating risk factors, supplementing the diet with calcium, bisphosphonates, and/or vitamin D, and treating with testosterone and/or estrogen when deficient. Sodium fluoride treatment and anabolic steroids may be used as alternatives. Septic arthritis is a medical emergency, and prompt recognition and rapid and aggressive treatment are critical to ensuring a good prognosis. The treatment of septic arthritis includes appropriate antimicrobial therapy and joint drainage. Adverse effects of prescribed antibacterials occur more often in the elderly patient than in young adults. The physician can help to minimise the incidence of adverse effects and improve outcomes by being aware of the principles of clinical pharmacology, the characteristics of specific drugs, and the special physical, psychological and social needs of older patients.

Bacterial arthritis in the elderly: an overview

The key to successful treatment of acute bacterial arthritis is early diagnosis and initiation of empirical antibacterial therapy. Treatment includes antimicrobial therapy, debridement of the infected joint and treatment of pain. Empirical antibacterial treatment should be re-evaluated as soon as the causative pathogen is identified from joint fluid and other cultures. Mobilisation with partial weight bearing is encouraged early during treatment. The outcome of properly treated bacterial arthritis in the elderly is generally favourable and at least 50% of patients may recover without developing secondary osteoarthritis.

Vertebral osteomyelitis at a Norwegian university hospital 1987-97: clinical features, laboratory findings and outcome

Altogether 40 patients aged 13-91 y (average 58 y) with vertebral osteomyelitis were treated at the Bergen University Hospital between July 1987 and June 1997. All patients presented with back pain, 33 (83%) had vertebral tenderness, and 26 (65%) patients were febrile. The duration of symptoms before diagnosis was < 3 weeks in 13 patients, and from 3 to 16 weeks in the remaining 27 patients. C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) were elevated in 39 and 38 patients, respectively. Staphylococcus aureus was the most frequent cause of osteomyelitis followed by Streptococcus spp., Escherichia coli and Mycobacterium tuberculosis. Magnetic resonance imaging was superior to other radiological methods and demonstrated changes consistent with osteomyelitis in all 23 patients examined with this method. 35 patients survived. 18/35 surviving patients had pareses and 17 underwent surgery with drainage of abscesses or laminectomy. All 35 patients made a good recovery and only 3 patients experienced permanent pareses. The diagnosis of vertebral osteomyelitis is easily missed, and treatment is often delayed, particularly in the elderly in whom signs of sepsis may not manifest. However, persisting localized pain and tenderness over the spine together with elevated CRP and ESR should prompt the physician to consider vertebral osteomyelitis. Fever and leukocytosis may support the diagnosis, but may not always be present.

Epidemiology of Staphylococcus aureus bacteremia in Denmark from 1957 to 1990

OBJECTIVE: To investigate the changes in epidemiology of Staphylococcus aureus (SA) bacteremia in Denmark over a 30-year period, where the population has remained stable. METHODS: Bacteriologic and clinical data were generated on 17 712 SA strains from virtually all SA bacteremia cases in Denmark from 1957 to 1990 submitted to our laboratory for phage typing. The data were related to information about population, hospital activity and blood-culturing activity during that period. RESULTS: SA bacteremia cases increased from 3 to 20/100 000 inhabitants per year, with the largest increases in incidence rates for the <1-year and >50-year age groups. While blood-culturing activity increased three-fold during the period, the rate of SA bacteremias actually decreased relative to the number of blood cultures taken. The increase in SA bacteremia cases was mainly due to increases in nosocomial infections for all age groups and was related to the increasing admission rates to Danish hospitals. Major shifts in antibiotic resistance patterns and phage types took place during the period, i.e. a marked reduction in multiresistant (including methicillin-resistant) strains, but could not explain the change in the epidemiology of the infections. CONCLUSIONS: The data indicate that increases in SA bacteremia rates correlated significantly with increasing numbers of admissions to hospitals. The main increase in SA bacteremia rates was represented by nosocomial infection, although increasing blood-culturing activity during the period may have contributed.

Increasing frequency of vertebral osteomyelitis following Staphylococcus aureus bacteraemia in Denmark 1980-1990

From 1980 to 1990, 309 cases of haematogenous osteomyelitis were identified in Denmark. Haematogenous osteomyelitis of the vertebral column increased significantly (P < 0.01) from the first to the second half of the period due to an increased number of patients > 50 years of age with community-acquired infection. Vertebral osteomyelitis differed significantly from osteomyelitis of other bones in accordance to age distribution (median 66 vs. 16 years), male/female ratio (75/71 vs. 105/ 58) and patients with diabetes (13% vs. 6%). We found a higher risk of haematogenous osteomyelitis in patients > 50 years of age and among patients with community-acquired infection. The highest incidence (5%) of vertebral osteomyelitis in Staphylococcus aureus bacteraemia in this age group was found in cases without an identified portal of entry. The highest incidence (34%) of osteomyelitis of other bones was found in community-acquired cases in the age group 1-20 years and without an identified portal of entry. The present study discusses reasons for the continued increase of vertebral osteomyelitis among adults and describes incidence rates and major risk factors for developing haematogenous osteomyelitis among patients with S. aureus bacteraemia. We suggest that the localization of haematogenous S. aureus osteomyelitis is connected with the presence of red bone marrow.

Brucellosis of the spine with a synchronous Staphylococcus aureus pyogenic elbow infection

Staphylococcus aureus osteomyelitis and pyogenic arthritis has a different pattern in the elderly than in the young. The axial skeleton is the most frequent site of infection and treatment is usually by intravenous antibiotics. We report a case of Staph. aureus septic arthritis of the elbow with concomitant osteomyelitis of the spine that was thought to be due to Staph. aureus, but culture of debrided material from the lesion grew Brucella in culture. We suggest that in the elderly it is advisable to obtain a tissue culture diagnosis and not to instigate therapy based on positive blood cultures or a concomitant infection.

Synovial fluid culture and blood culture in acute arthritis. A multi-case report of 90 patients

The use of blood culture methods for culture of synovial fluid (SF) has been suggested to increase the yield of microbes from SF of patients with septic arthritis. We report on a study of 94 SF cultures of 90 adult patients with acute effusions of the knee joint. Three different culture methods were used: conventional agar plate culture, culture with lysis and centrifugation (Isolator) and broth enrichment (BACTEC 6A and 7A). Blood was cultured simultaneously from 76 patients. In the patients with clinical septic arthritis, the SF cultures were positive by all the methods in 8 patients and negative by all the methods in 19 patients. The contamination rate of the SF cultures was 3/215 in the patients without clinical septic arthritis. We conclude that reliable evidence of septic arthritis is emerged from a SF culture by a single method, and that the choice of culture method is less critical. In addition, we discuss the role of blood cultures in the diagnosis of acute arthritides.

Bacteremia at a Danish university hospital during a twenty-five-year period (1968-1992)

In the 25-year period 1968-92, 3,317 out of 477,420 patients admitted to Frederiksberg Hospital experienced 3,491 episodes of bacteremia. Enterobacteriaceae dominated as causative agents (57%), following by Gram-positive cocci (31%) and anaerobes (7%). Polymicrobial bacteremia was found in 8% of the episodes. The incidence of Enterobacteriaceae bacteremia culminated in the middle (1978-82) of the period (4.7/1,000 admissions) and decreased during the last decade. Gram-positive bacteremia increased throughout the period (from 1.8 to 2.9; p < 0.001), due mainly to increasing incidences of bacteremia caused by non-hemolytic streptococci, Streptococcus pneumoniae and coagulase-negative staphylococci. Bacteroides fragilis accounted for a rising incidence of anaerobic bacteremia (from 0.3 to 0.7; p < 0.05). Clinical data were available for the 2,599 bacteremic episodes in the 20-year period 1968-87. 59% of these were hospital acquired. Of those, 38% were associated with indwelling catheters, mainly bladder catheters (28%) and i.v. lines (7%). The urinary tract dominated as source of bacteremia (46%), followed by the respiratory (11%) and the gastrointestinal tract (9%). Half of the patients had predisposing underlying diseases, most frequently malignancies (20%) and diabetes mellitus (7%). The mortality rate related to bacteremia decreased from 25% to 11% (p < 0.001). More than half (55%) of the fatal cases related to bacteremia occurred within the first 2 days after the first positive blood culture was obtained. Logistic regression analysis defined 7 variables that independently influenced the outcome related to bacteremia: age, source, culture verification of source, shock, body temperature, leukocyte count and empiric antibiotic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiology of Staphylococcus aureus bacteremia in Denmark

The number of Staphylococcus aureus bacteremia cases has increased annually in Denmark during the latest decades. This increase has occurred among older patients with hospital-acquired bacteremia. Methicillin-resistance, which earlier was a property of strains of the 83A phage-complex, has nearly disappeared, while the frequency of penicillin-resistance has increased. Today both the phage-type pattern and antibiotic resistance are nearly similar for strains from hospital-acquired and community-acquired cases. In hospitals the frequency of bacteremia after postoperative wound infections has decreased, while cases associated with intravascular catheters has increased, and these infections are now the most common cause of hospital-acquired S. aureus bacteremia. Endocarditis is most commonly found in community-acquired cases without an identified primary focus in patients between 21-50 years. Also hematogenous osteomyelitis is most common in community-acquired cases, but these infections have changed to having a high predilection for the vertebral column, and the prevalence of chronic cases has decreased.