Implant Sonication versus Tissue Culture for the Diagnosis of Spinal Implant Infection

Peking University First Hospital Procedure for Culturing Pathogenic Microorganisms for Bone and Joint Infection

Background

This retrospective cohort study explores a practical approach to acquiring pathogenic microorganisms in patients with bone and joint infections.

Methods

From Aug 2018 to Mar 2022, 68 consecutive patients (87 cultures) with bone and joint infection were recruited in this study. All cultures followed the Peking University First Hospital Procedure of Culturing Pathogenic microorganisms for bone and joint infection. Tissue samples were obtained through fluoroscopy-guided biopsy or open debridement. Tissue samples were divided into manual homogenization (MH), manual mixture (MM), and pathological examination. The baseline, antibiotic exposure, laboratory, surgical, and microbial data were reviewed. Independent sample T-test, Mann-Whitney U-test, and Chi-square test were used to detect the difference between patients who received different processing measures.

Results

The average age was 55.8±2.4 years old. Thirty-nine patients were male. The total positive culture rate of the manual homogenization group was 80.5% (70/87). Thirty-five patients had mixed infections with more than one microorganism cultured. Staphylococci accounted for 60.23% of all microorganisms. Staphylococcus aureus (18.2%) and Staphylococcus epidermidis (15.9%) were the two most common bacteria cultured in this study. Patients with positive culture in the manual mixture group had significantly higher WBC (p = 0.006), NE% (p = 0.024), ESR (p = 0.003), CRP (p = 0.020) and IL6 (0.050) compared to patients with negative culture. After tissue homogenization, only ESR is still statistically different. Patients without SIRS had a low positive culture rate (59.4%). Tissue homogenization could significantly increase the positive culture rate of patients without SIRS. Pre-culture antibiotic exposure was not an independent risk factor for culture results.

Conclusion

Peking University First Hospital Procedure for Culturing Pathogenic microorganisms for Bone and Joint Infections was a practical approach for obtaining pathogenic microorganisms.

Practical Guidance for Clinical Microbiology Laboratories: Microbiologic diagnosis of implant-associated infections

SUMMARYImplant-associated infections (IAIs) pose serious threats to patients and can be associated with significant morbidity and mortality. These infections may be difficult to diagnose due, in part, to biofilm formation on device surfaces, and because even when microbes are found, their clinical significance may be unclear. Despite recent advances in laboratory testing, IAIs remain a diagnostic challenge. From a therapeutic standpoint, many IAIs currently require device removal and prolonged courses of antimicrobial therapy to effect a cure. Therefore, making an accurate diagnosis, defining both the presence of infection and the involved microorganisms, is paramount. The sensitivity of standard microbial culture for IAI diagnosis varies depending on the type of IAI, the specimen analyzed, and the culture technique(s) used. Although IAI-specific culture-based diagnostics have been described, the challenge of culture-negative IAIs remains. Given this, molecular assays, including both nucleic acid amplification tests and next-generation sequencing-based assays, have been used. In this review, an overview of these challenging infections is presented, as well as an approach to their diagnosis from a microbiologic perspective.

Interdisciplinary Infection Prevention and Control Bundle in Neurosurgical Patients: Results of a Prospective Cohort Study

BACKGROUND

Surgical site infections (SSIs) account for one of the most common causes of nosocomial infections. Bundle approaches for infection prevention and control do not capture the full complexity of neurosurgical interventions.

OBJECTIVE

To study the efficacy of an interdisciplinary infection prevention and control bundle (IPCB) in neurosurgery.

METHODS

This was a prospective, single-center, observational study, analyzing 3 periods: before (2014), during (2017), and after (2019) full implementation of IPCB. IPCB included the following infection prevention measures: preoperative decolonization, patient engagement, operating room (OR) hygiene protocol, and pre-, peri-, and postoperative standard operating procedures (SOPs) while infection control measures included intraoperative sonication, blood culture inoculation, and interdisciplinary SSI management. All neurosurgical patients being readmitted to the hospital for SSIs within 90 days after receiving index surgery were included in the trial (403/9305).

RESULTS

Implementation of IPCB resulted in more frequently succeeded pathogen isolation in patients with SSI (2014: 138 isolates in 105 (83%) patients with SSI, 2017: 169 isolates in 124 (91%) patients with SSI, and 2019: 199 isolates in 136 (97%) patients with SSI; P < .001). Proportion of gram-positive SSI and virulence was declining ( P = .041, P = .007). The number of repeated revision surgeries decreased from 26 (20%) in 2014 and 31 (23%) in 2017 to 18 (13%) in 2019 ( P = .085). Significantly, fewer patients experienced sepsis in response to SSI (2014: 12%, 2017: 10%, and 2019: 3.6%, P = .035). In-hospital mortality rate was declining from 12 (9.4%) in 2014 to 9 (6.6%) in 2017 to 5 (3.6%) in 2019 ( P = .148).

CONCLUSION

Introducing an interdisciplinary IPCB in neurosurgery leads to a significant reduction of sepsis and decreased in-hospital mortality while a pathogen switch toward gram-negative bacteria was observed. Minimizing diagnostic gap of pathogen detection toward a more efficient anti-infective treatment may be the main reason for the substantial decrease in morbidity and mortality.

An Assessment of the Safety of Surgery and Hardware Placement in de-novo Spinal Infections. A Systematic Review and Meta-Analysis of the Literature

OBJECTIVES

Primary objectives were outcomes comparison of instrumented surgery used for de-novo spinal infections in terms of infection recurrence, reoperations, primary failure, mortality, and length of stay relative to non-instrumented surgery. Secondary objectives were outcomes for surgical and non-surgical treatment of de-novo spinal infections regarding recurrence of infection, mortality, quality of life, and length-of-stay.

METHODS

A systematic literature review was performed using the PubMed database. Studies comparing outcome variables of patients with de-novo spinal infections (DNSI) treated with and without instrumentation and surgical versus non-surgical treatment were included. Studies primarily focusing on epidural abscesses or non-de-novo infections were excluded. A meta-analysis was performed for infection recurrence, reoperation, primary treatment failure, mortality, and quality-of-life parameters.

RESULTS

A total of 17 retrospective studies with 2.069 patients met the inclusion criteria. 1.378 patients received surgical treatment with or without instrumentation; 676 patients were treated non-surgically. For the comparison of instrumented to non-instrumented surgery Odds-Ratios were .98 (P = .95) for infection recurrence, .83 (P = .92) for primary failure, .53 (P = .02) for mortality and .32 (P = .05) for reoperation. For the comparison of non-surgical to surgical treatment, Odds-Ratios were .98 (P = .95) for infection recurrence, and 1.05 (P = .89) for mortality.

CONCLUSION

Available data support that instrumented surgery can be performed safely without higher rates of infection recurrence or primary failure and lower reoperation and mortality rates compared to nonsurgical treatment for DNSI. Furthermore, spine surgical treatment may generally be performed without higher risk of infection recurrence and mortality and better quality-of-life outcomes compared to generic non-surgical treatment.

Changes of the microbiological spectrum and antibiotic resistance pattern in postoperative spinal implant infections with multiple culture-positive revision surgeries

BACKGROUND CONTEXT

In severe cases of postoperative spinal implant infections (PSII) multiple revision surgeries may be needed. Little is known if changes in the microbiological spectrum and antibiotic resistance pattern occur between revision surgeries.

PURPOSE

Analysis of the microbiological spectrum and antibiotic resistance pattern in patients with multiple revision surgeries for the treatment of PSII STUDY DESIGN: Retrospective database analysis.

PATIENT SAMPLE

Between 01/2011 and 12/2018, 103 patients underwent 248 revision surgeries for the treatment of PSII. Twenty patients (19.4%) who underwent multiple revision surgeries for PSII were included in this study.

OUTCOME MEASURES

Microbiological spectrum, antibiotic resistance pattern.

METHODS

A retrospective analysis of a prospectively maintained single center spine infection database was performed with a minimum follow-up of 3 years. Overall, 20 patients (six male/14 female) underwent 82 revisions for PSII (median 3; range 2-12). There were 55 of 82 (67.1%) procedures with a positive microbiological result. Microbiological analysis was performed on tissue and implant sonication fluid. Changes in microbial spectrum and antibiotic resistance pattern between surgeries were evaluated using Chi-Square and Fisher's exact test.

RESULTS

In total, 74 microorganisms (83.3% gram-positive; 10.8% gram-negative) were identified. The most common microorganisms were Staphylococcus epidermidis (18.9%) and Cutibacterium acnes (18.9%). All S. epidermidis identified were methicillin-resistant (MRSE). Overall, there were 15 of 55 (27.3%) polymicrobial infections. The microbiological spectrum changed in 57.1% (20/35) between the revision stages over the entire PSII period. In 42.9% (15/35) the microorganism persisted between the revision surgeries stages. Overall, changes of the antibiotic resistance pattern were seen in 17.4% (8/46) of the detected microorganisms, comparing index revision and all subsequent re-revisions. Moreover, higher resistance rates were found for moxifloxacin and for ciprofloxacin at first re-revision surgery compared with index PSII revision. Resistances against vancomycin increased from 4.5% (1/23) at index PSII revision to 7.7% (2/26) at first re-revision surgery.

CONCLUSIONS

Changes of the microbiological spectrum and the resistance pattern can occur in patients with severe PSII who require multiple revision surgeries. It is important to consider these findings in the antimicrobial treatment of PSII. The microbiological analysis of intraoperative tissue samples should be performed at every revision procedure for PSII.

Environmental, Microbiological, and Immunological Features of Bacterial Biofilms Associated with Implanted Medical Devices

The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.

Sacral Insufficiency Fracture Following Short-Segment Lumbosacral Fusion: Case Series and Review of the Literature

STUDY DESIGN

Retrospective case series.

OBJECTIVE

Sacral insufficiency fracture is a rare and serious complication following lumbar spine instrumented fusion. The purpose of this study was to describe the patient characteristics, presentation, evaluation, treatment options, and outcomes for patients with sacral insufficiency fracture after short-segment lumbosacral fusion.

METHODS

Six patients from our institutional database and 16 patients from literature review were identified with a sacral insufficiency fracture after short-segment (L4-S1 or L5-S1) lumbar fusion within 1 year of surgery.

RESULTS

Patients were 55% female with a mean age of 58 years and body mass index of 30 kg/m². Osteoporosis or osteopenia was the most common comorbidity (85%). Half of patients sustained a sacral fracture after surgery from a posterior approach, while the others had anterior or anterior-posterior surgery. Mean time to fracture was 42 days with patients clinically presenting with new sacral pain (86%), radiculopathy (60%), or neurologic deficit (5%). Ultimately, 73% of patients underwent operative fixation often involving extension of the construct (75%) and fusion to the pelvis (69%). Men (P = .02) and patients with new radicular pain or neurologic deficit (P = .01) were more likely to undergo revision surgical treatment while women over 50 years of age were more likely to be treated conservatively (P = .003).

CONCLUSIONS

Spine surgeons should monitor for sacral insufficiency fracture as a source of new-onset pain in the postoperative period in patients with a short segment fusion to the sacrum. The recognition of this complication should prompt an assessment of bone health and management of underlying bone fragility.