Management of Propionibacterium acnes infection after shoulder surgery

Ulnar Collateral Ligament Reconstruction Is Commonly Performed Using a Palmaris Graft and Provides Favorable Patient Outcomes With Variable Return-to-Play and Postoperative Complication Rates: A Systematic Review

PURPOSE

To systematically review the literature to provide an updated evaluation of postoperative clinical outcomes, return to play (RTP), and postoperative complications after primary ulnar collateral ligament reconstruction (UCLR) in throwing and nonthrowing athletes at minimum 2-year follow-up.

METHODS

A literature search was performed on November 25, 2023, by querying the Embase, PubMed, and Scopus online databases using the 2020 Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. The inclusion criteria consisted of Level I to IV human clinical studies reporting postoperative outcomes and/or complications after primary UCLR with minimum 2-year follow-up. The exclusion criteria consisted of non-English-language studies; biomechanical, animal, and cadaveric studies; review articles; letters to the editor; and studies not reporting postoperative outcomes or complications. Study quality was evaluated using the Methodological Index for Non-Randomized Studies criteria. The incidence of reported complications among the included studies was extracted. Clinical outcome scores included the Kerlan-Jobe Orthopaedic Clinic Shoulder & Elbow (KJOC) score, Andrews-Timmerman (AT) score, and satisfaction score. RTP data were also extracted.

RESULTS

A total of 21 studies published from 2006 to 2023, consisting of 2,452 patients (2,420 male patients) with a mean age of 21.7 years (mean range, 12-65 years) and mean follow-up period of 50.5 months (mean range, 24-151.2 months), were included. The mean Methodological Index for Non-Randomized Studies score was 16 (range, 13-20). A total of 46% of patients (1,138 of 2,452) underwent concomitant ulnar nerve transposition. Palmaris graft was the most frequently used method (66.6%; n = 1,799), followed by hamstring graft (26.0%, n = 703). At the final follow-up, mean postoperative KJOC scores ranged from 72.0 to 88.0; mean AT scores, from 83.6 to 98.3; and mean satisfaction scores, from 86.1 to 98.3. The overall RTP rate ranged from 62.5% to 100% at a mean range of 9.5 to 18.5 months. The total incidence of complications ranged from 0% to 31.8%, with 0% to 7.4% of patients undergoing revision surgery.

CONCLUSIONS

UCLR was commonly performed using a palmaris graft, with concomitant ulnar nerve transposition reported in 46% of patients. At a mean follow-up of 50.5 months, mean postoperative KJOC scores ranged from 72 to 98.3, AT scores ranged from 83.6 to 98.3, and satisfaction scores ranged from 86.1 to 98.3, with variable RTP rates.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II to IV studies.

Chronological changes in the rate of surgical field contamination in the shoulder joint

BACKGROUND

In shoulder surgery, low-virulence bacteria such as Cutibacterium acnes and coagulase-negative staphylococci can cause postoperative infection. However, the degree of sterility during surgery after disinfection is not known, and the efficacy of double skin preparation for such bacteria is unclear. This study aimed to evaluate chronological changes in the surgical field contamination rate in the shoulder joint and to compare single and double skin preparation.

METHODS

In total, 126 shoulders in 121 patients undergoing shoulder surgery (64 men, 62 women; mean age 64 years) were enrolled. Patients were divided into two groups: single skin preparation, where the site was painted with 10% povidone iodine, and double skin preparation, where the site was treated with 1% chlorhexidine gluconate/83% isopropyl alcohol and painted 10% povidone iodine. Swab samples from the axillary and proximal areas in the surgical field were collected chronologically before starting surgery and at 30, 60, and 120 min after starting surgery (MAS). The contamination rate of each sample was compared and detected species were evaluated.

RESULTS

The contamination rate for the axillary area was 48.4%, 85.9%, 95.3%, and 97.1% in the single-preparation group and 32.3%, 72.6%, 87.1%, and 91.2% in the double-preparation group before starting surgery and 30, 60, and 120 MAS, respectively, and that the proximal area was 12.5%, 26.6%, 29.7%, and 35.3% in the single-preparation group and 16.1%, 19.4%, 27.4%, and 38.2% in the double-preparation group, respectively. Significant differences were not seen between the groups by area or time point. Most detected species were Cutibacterium acnes and coagulase-negative staphylococci.

CONCLUSIONS

The incidence of surgical field contamination in shoulder joint was high from immediately after starting surgery. In the axillary area, the contamination rates exceeded 70% from 30 MAS in both groups. Measures against infection should be instituted considering these findings when performing shoulder surgery.

Image-Guided Biopsy in Acute Diskitis-Osteomyelitis: A Systematic Review and Meta-Analysis

BACKGROUND. The reported sensitivity and yield of image-guided biopsies for diskitis-osteomyelitis vary widely. OBJECTIVE. The purpose of this study was to perform a systematic review of the literature and meta-analysis of pooled sensitivity data to elucidate strategies for optimal image-guided biopsies among patients suspected to have diskitis-osteomyelitis. EVIDENCE ACQUISITION. A comprehensive literature search was performed for studies of patient populations with proven or suspected diskitis-osteomyelitis that included percutaneous image-guided biopsy as part of the workup algorithm. Type of pathogens, imaging modality used for biopsy guidance, tissue targeted, antibiotic administration at the time of biopsy, true microbiology positives, true microbiology negatives, false microbiology positives, false microbiology negatives, disease (i.e., diskitis-osteomyelitis) positives as determined by reference standard, true infection positives (i.e., positive microbiology or pathology results), and total number of biopsies performed were extracted from the studies. Microbiology sensitivity, microbiology biopsy yield, and infection sensitivity were calculated from the pooled data. These terms and the data required to calculate them were also defined in detail. EVIDENCE SYNTHESIS. Thirty-six articles satisfied inclusion criteria and were used for analysis. The pooled microbiology sensitivity, infection sensitivity, and microbiology biopsy yields were 46.6%, 70.0%, and 26.7%, respectively. Mycobacterium tuberculosis-only microbiology sensitivity was significantly higher than both pyogenic bacteria and mixed-organism microbiology sensitivity (p < .001). Staphylococcus aureus was the most common causative organism (28.6%). Pooled microbiology sensitivity was not significantly different for CT guidance and fluoroscopy guidance (p = .16). There was a statistically significant difference between pooled microbiology sensitivity of bone/end plate (45.5%) and disk/paravertebral soft-tissue (64.8%) image-guided biopsies (p < .001). There was no statistically significant difference in pooled microbiology sensitivities for patients who received antibiotics before the procedure (46.2%) and those who did not (44.6%) (p = .70). CONCLUSION. Image guidance by CT or fluoroscopy does not affect microbiology yield, disk and paravertebral soft-tissue biopsies should be considered over bone and end plate biopsies, and preprocedural antibiotic administration does not appear to impact biopsy results. CLINICAL IMPACT. Understanding and correctly applying reported statistics contribute to appropriate interpretation of the abundant literature on this topic and optimization of care for patients with diskitis-osteomyelitis.

Evaluation of the effectiveness of skin preparation methods for the reduction of Cutibacterium acnes (formerly Propionibacterium acnes) in shoulder surgery: a systematic review

Background

Cutibacterium acnes (C. acnes) is the most common pathogen responsible for post-operative shoulder infections. The purpose of this study was to evaluate the effectiveness of skin preparation methods against C. acnes in shoulder surgery.

Methods

A systematic review was conducted evaluating the effectiveness of skin preparation methods in the reduction of C. acnes in patients undergoing shoulder surgery. Outcomes were assessed based on the effectiveness of the method used; side effects and cost were also analysed.

Results

Of the 19 included studies, 9 evaluated pre-surgical home treatments: 8 assessed benzoyl peroxide (BPO) and 6 concluded it is effective in reducing C. acnes. Nine studies assessed surgical skin preparation and concluded that Chlorhexidine gluconate (CHG) was not effective; in contrast hydrogen peroxide reduced C. acnes. Finally, one study evaluated an aseptic protocol using CHG and concluded that it was not effective.

Conclusions

It was demonstrated that BPO as home treatment is effective in reducing C. acnes load on skin; it rarely causes side effects and is also cost-effective. This study highlights non-effectiveness of CHG. There was some evidence that the addition of hydrogen peroxide could have a positive effect in the reduction of C. acnes skin load; however, more studies are required.

Rapid detection of bacteria using gold nanoparticles in SERS with three different capping agents: Thioglucose, polyvinylpyrrolidone, and citrate

The increase in outbreaks of emerging and re-emerging bacterial infections over the last few decades calls for their rapid detection and treatment. Surface-enhanced Raman spectroscopy (SERS) is a technique that can be applied to develop fast screening systems for bacterial presence in biological samples. Optimizing the capping agents in nanoparticle synthesis is important because capping agents are responsible for controlling the morphological features and chemical properties of the nanoparticles that are essential for SERS. To the best of our knowledge, this paper is the first to study the application of gold nanoparticles capped with thioglucose and polyvinylpyrrolidone (PVP) in SERS detection of bacteria as an alternative to the citrate-capped gold nanoparticles that are often used in SERS detection of bacteria. Three different species of bacteria were used in this study: Cutibacterium acnes, Escherichia coli and Staphylococcus aureus (methicillin-sensitive and methicillin-resistant). This study demonstrates that the thioglucose, citrate both show good contribution in bacterial species identification and the thioglucose shows the best among the three capping agents in two types of S. aureus identification. Moreover, although PVP showed high Raman peaks in the SERS spectrum for each type of bacteria, it showed least contribution in identifying species and strains due to its low efficacy in producing responses from different nucleic acid components in the bacteria cells.

Ultrasound evaluations and guided procedures of the painful joint arthroplasty

The purpose of this article is to describe the use of ultrasound for the diagnosis and treatment of painful joint arthroplasty. Ultrasound plays a crucial role in the diagnosis of the painful joint arthroplasty, especially given its unique dynamic capabilities, convenience, and high resolution. Ultrasound guidance is also instrumental for procedures in both diagnosing and in select cases, treating the painful joint arthroplasty. Topics to be discussed in this article include trends in arthroplasty placement, benefits of the use of ultrasound overall, and ultrasound evaluation of periprosthetic joint infections. We will also review the sonographic findings with dissociated/displaced components and adverse reaction to metallic debris including metallosis, trunnionosis, and metal-on-metal pseudotumors. Additionally, we will discuss ultrasound evaluation of tendon pathologies with arthroplasties, including dynamic maneuvers to evaluate for tendon impingement/snapping. Finally, we will cover ultrasound-guided joint arthroplasty injection indications and precautions. KEY POINTS: • Ultrasound is preferred over MRI in patients with joint arthroplasty and plays a crucial role in diagnosis, especially given its unique dynamic capabilities, convenience and high resolution. • It is especially beneficial for US-guided aspiration in periprosthetic joint infections; effectively used to evaluate periprosthetic fluid collections, facilitating differentiation between abscesses and aseptic collections, and tracking sinus tracts. • Recently, the diagnosis of periprosthetic joint infections has shifted focus to biomarkers in the periprosthetic fluid, specifically α-defensin, which has a high sensitivity and specificity for diagnosing infection. • Cutibacterium acnes is a major pathogen responsible for shoulder arthroplasty infections, often presenting with normal laboratory values and since slow growing, must be kept for a minimum of 14 days.

Risk factors for cardiac implantable electronic device infections: a nationwide Danish study

AIMS

Cardiac implantable electronic device (CIED) infection is a severe complication to modern management of cardiac arrhythmias. The CIED type and the type of surgery are recognized as risk factors for CIED infections, but knowledge of patient-related risk factors is scarce. This study aimed to identify lifelong patient-related risk factors for CIED infections.

METHODS AND RESULTS

Consecutive Danish patients undergoing a CIED implantation or reoperation between January 1996 and April 2018 were included. The cohort consisted of 84 429 patients undergoing 108 494 CIED surgeries with a combined follow-up of 458 257 CIED-years. A total of 1556 CIED explantations were classified as either pocket (n = 1022) or systemic CIED infection (n = 534). Data were cross-linked with records from the Danish National Patient Registry and the Danish National Prescription Registry. Using multiple-record and multiple-event per subject proportional hazard analysis, specific patient-related risk factors were identified but with several variations amongst the subtypes of CIED infection. CIED reoperations were associated with the highest risk of pocket CIED infection but also CIED type, young age, and prior valvular surgery [hazard ratio (HR): 1.62, 95% confidence interval (CI): 1.29-2.04]. Severe renal insufficiency/dialysis (HR: 2.40, 95% CI: 1.65-3.49), dermatitis (HR: 2.80, 95% CI: 1.92-4.05), and prior valvular surgery (HR: 2.09, 95% CI: 1.59-2.75) were associated with the highest risk of systemic CIED infections. Congestive heart failure, ischaemic heart disease, malignancy, chronic obstructive pulmonary disease, and temporary pacing were not significant at multivariate analysis.

CONCLUSION

Specific comorbidities and surgical procedures were associated with a higher risk of CIED infections but with variations amongst pocket and systemic CIED infection. Pocket CIED infections were associated with CIED reoperations, young age and more complex type of CIED, whereas systemic CIED infections were associated with risk factors predisposing to bacteraemia.

Short-term outcomes of two-stage reverse total shoulder arthroplasty with antibiotic-loaded cement spacer for shoulder infection

Background

The purpose of our study was to investigate short-term outcomes of two-stage reverse total shoulder arthroplasty (RTSA) with an antibiotic-loaded cement spacer for shoulder infection.

Methods

Eleven patients with shoulder infection were treated by two-stage RTSA following temporary antibiotic-loaded cement spacer. Of the 11 shoulders, nine had pyogenic arthritis combined with complex conditions such as recurrent infection, extensive osteomyelitis, osteoarthritis, or massive rotator cuff tear and two had periprosthetic joint infection (PJI). The mean follow-up period was 29.9 months (range, 12–48 months) after RTSA. Clinical and radiographic outcomes were evaluated using the visual analog scale (VAS) score for pain, American Shoulder and Elbow Surgeons (ASES) score, subjective shoulder value (SSV), and serial plain radiographs.

Results

The mean time from antibiotic-loaded cement spacer to RTSA was 9.2 months (range, 1–35 months). All patients had no clinical and radiographic signs of recurrent infection at final follow-up. The mean final VAS score, ASES score, and SSV were significantly improved from 4.5, 38.6, and 29.1% before RTSA to 1.7, 75.1, and 75.9% at final follow-up, respectively. The mean forward flexion, abduction, external rotation, and internal rotation were improved from 50.0°, 50.9°, 17.7°, and sacrum level before RTSA to 127.3°, 110.0°, 51.8°, and L2 level at final follow-up, respectively.

Conclusions

Two-stage RTSA with antibiotic-loaded cement spacer yields satisfactory short-term clinical and radiographic outcomes. In patients with pyogenic arthritis combined with complex conditions or PJI, two-stage RTSA with an antibiotic-loaded cement spacer would be a successful approach to eradicate infection and to improve function with pain relief.

Is clindamycin a potential treatment for prostatitis?

Cutibacterium acnes has been associated with chronic prostatitis, which can potentially favor the appearance of tumors in the prostate. Prostatitis is difficult to treat, and the drug needs to be able to penetrate the prostate. The aim was to investigate the pharmacokinetics of clindamycin in the interstitial fluid of rat prostate using microdialysis. Microdialysis probes were recovered in vitro and in vivo. Clindamycin was administered at 80 mg/kg iv bolus for plasma and tissue pharmacokinetic experiments. A microdialysis probe was implanted in the prostate gland for collections over an 8-hour period. The pharmacokinetic parameters were determined by both compartmental and non-compartmental approaches. Penetration was determined as the ratio between the area under the curve and the time of the clindamycin measurement in the prostate. The recovery of the in vivo probes was 38.11 ± 1.14%. The plasma profile was modeled by a two-compartment pharmacokinetic model. Clindamycin presented a prostate/plasma ratio of 1.02, with free concentrations above the minimum inhibitory concentration for Cutibacterium acnes isolates. This was the first study that determined clindamycin free concentrations in the prostatic fluid of rats. These findings suggest that clindamycin may be an effective alternative for the treatment of prostatitis caused by Cutibacterium acnes.

Efficacy of combinational therapy using blue light and benzoyl peroxide in reducing Cutibacterium acnes bioburden at the deltopectoral interval: a randomized controlled trial

BACKGROUND

The purpose of this study was to compare the efficacy of blue light therapy (BLT) and 5% topical benzoyl peroxide (BPO) gel in combination with standard chlorhexidine (CHX) preparation in eradicating Cutibacterium acnes at the deltopectoral interval measured by positive, quantitative culture findings.

METHODS

Adult male volunteers were randomized to 1 of 3 treatment groups: BPO, BLT, and BPO followed by BLT. Contralateral shoulders served as matched controls. Volunteers randomized to BPO applied the gel for a total of 5 treatments. In the BLT group, a single 23-minute treatment was administered at an estimated irradiance of 40 mW/cm² (radiant exposure, 55.2 J/cm²). In the BPO-BLT group, volunteers received both treatments as described earlier. After treatment with either BPO, BLT, or both, a single swab culture was taken from the treatment shoulder. Next, control and treatment shoulders were prepared with CHX, and cultures were taken from each shoulder. Cultures were sent for anaerobic quantitative growth analysis with both polymerase chain reaction and Sanger sequencing confirmation of presumptive C acnes colonies.

RESULTS

This study enrolled 60 male volunteers, 20 per group, with no loss to follow-up. After treatment but prior to CHX administration, all culture samples in the BPO group and BLT group grew C acnes. Prior to CHX, 16 samples (80%) in the BPO-BLT group grew C acnes. On quantitative analysis, the BPO group and BPO-BLT group had significantly less growth of C acnes compared with the BLT group after treatment but prior to CHX (P < .05 for each). Following CHX administration, the BPO and BPO-BLT groups had significantly fewer positive culture findings (odds ratios of 0.03 and 0.29, respectively) and less quantity of growth compared with their control arms (P < .05). This was not seen in the BLT group. For quantitative between-group analysis, no significant synergistic effects were seen with BPO-BLT compared with BPO alone (P = .688). There was no difference in side effects between groups.

CONCLUSION

The combination of topical BPO and CHX was effective at eliminating C acnes in most cases. BLT alone did not demonstrate effective antimicrobial properties against C acnes at the radiant exposure administered in this study. Combining BPO and BLT did not lead to significant synergistic antimicrobial effects. Both BPO and BLT are safe with few, transient side effects reported. More work is needed to determine whether BLT at higher radiant exposures or serial treatment results in bactericidal effects against C acnes in vivo.

The management of the shoulder skin microbiome (Cutibacterium acnes) in the context of shoulder surgery: a review of the current literature

BACKGROUND

This review aims to establish current knowledge of the shoulder skin microbiome and how to manage the bacteria that reside within it.

METHODS

A review was undertaken of the current literature through OvidSP. All abstracts were reviewed by three independent researchers.

RESULTS

Thirty-five studies met the inclusion criteria. With forward referencing an additional 14 were included. None commented on organisms specific to the shoulder microbiome other than Cutibacterium acnes. Therefore, this review is focussed on the current knowledge of C. acnes.

DISCUSSION

C. acnes is a skin commensal within the pilo-sebaceous glands reported to be the primary pathogen in up to 86% of shoulder joint infections. Pre-operative culture of unprepared skin can be indicative of underlying joint infection in shoulder arthroplasty revision. Intra-articular biopsies may have a high false positive due to skin contamination. Correlating the number of positive samples and certain associated signs can give a greater than 90% probability of a true infection. Standard surgical skin preparation, peri-surgical intravenous antibiotics and oral pre-operative antibiotics do not reduce bacterial load within the skin. However, topical benzoyl peroxide and clindamycin have both demonstrated significantly reduced bacteria load. Phylogenetically there are six main types. Patients may have more than one phenotype present during infection.

Development of a 3D Bioartificial Shoulder Joint Implant Mimetic of Periprosthetic Joint Infection

Post-surgical infections of the shoulder joint involving Cutibacterium acnes are difficult to diagnose and manage. Despite the devastating clinical complications and costly healthcare burden of joint infections, the scarcity of joint infection models was identified as an unmet need by the 2019 International Consensus on Orthopedic Infections. In this study, we have developed a novel 3D shoulder joint implant mimetic (S-JIM) that includes a surgical metal surface and supports a co-culture of C. acnes and patient-derived shoulder capsule fibroblasts. Our findings indicate the S-JIM can generate a near anaerobic interior environment that allows for C. acnes proliferation and elicit fibroblast cell lysis responses that are consistent with clinical reports of tissue necrosis. Using the S-JIM, we provided proof-of-concept for the use of mass spectrometry in real-time detection of C. acnes joint infections during surgery. The S-JIM is the first in vitro cell culture-based biomimetic of periprosthetic joint infection that provides a preclinical method for the rapid and reliable testing of novel anti-PJI interventions.

Complications Associated With Intravenous Antibiotic Treatment for Cutibacterium acnes Periprosthetic Shoulder Infection

Whether positive Cutibacterium acnes cultures during revision shoulder arthroplasty represent true periprosthetic joint infection (PJI), deep tissue inoculant, or laboratory contaminant is a point of substantial controversy. The purpose of this study was to review complications of intravenous antibiotics used for treatment of presumed C acnes shoulder PJI. A study population of 26 patients treated for C acnes PJI with a minimum follow-up of 2 years after operative treatment was established. Complication occurrence and severity were obtained through chart review and phone survey. Sixteen (61.5%) patients experienced a therapeutic complication. Twelve (46.2%) patients experienced a total of 47 antibiotic-associated adverse effects and 10 (38.5%) patients experienced 11 total peripherally inserted central catheter line-associated complications. Female sex carried an increased risk for severe complications (relative risk, 3.3; 95% CI, 1.2-9.5; P=.024). Treatment duration of greater than 6 weeks was a significant predictor for the total number of complications experienced [F(1,23)=5.361; P=.030; adjusted R²=0.189]. Age older than 65 years, treatment duration greater than 6 weeks, and female sex were significant predictors for the number of severe complications [F(3,21)=3.249; P=.042; adjusted R²=0.219]. Treating C acnes infection with intravenous antibiotics carries a substantial risk of adverse events, highlighting the importance of accurate diagnosis of shoulder PJI. Further investigations into the efficacy and safety profile of oral antibiotics for shoulder PJI are necessary. [Orthopedics. 2021;44(3):e422-e426.].

Undergoing an Arthroscopic Procedure Prior to Shoulder Arthroplasty is Associated With Greater Risk of Prosthetic Joint Infection

PURPOSE

To utilize a national all-payer claims dataset to understand whether a history of a prior shoulder arthroscopy is associated with adverse outcomes or complications after the index shoulder arthroplasty itself.

METHODS

The Symphony Integrated DataVerse, an all-payer claims database, was used to identify patients undergoing primary shoulder arthroplasty (hemiarthroplasty, anatomic total shoulder arthroplasty, or reverse total shoulder arthroplasty) between 2017 to 2018. Current Procedural Terminology codes were used to identify patients who had undergone a shoulder arthroscopic procedure on the ipsilateral side within 2 years before the arthroplasty. Multivariate logistic regression analyses were used to assess whether prior shoulder arthroscopy was associated with higher risks of wound complications, postoperative stiffness, mechanical complications, prosthetic joint infection, revision surgery and readmissions within 90 days of the arthroplasty.

RESULTS

In total, 19,429 patients were included, of which 837 (4.3%) had undergone shoulder arthroscopy within 2 years before the arthroplasty. Prior shoulder arthroscopy was associated with a significantly higher risk of prosthetic joint infection (odds ratio [OR] 2.74 [95% confidence interval {CI} 1.51-4.69]; P < .001) within 90 days of the arthroplasty. The greatest risk of prosthetic joint infection was associated with arthroscopies that took place within 3 months before the arthroplasty (OR 5.32 [95% CI 1.42-15.14]; P = .005).

CONCLUSIONS

Undergoing an arthroscopic procedure of the ipsilateral shoulder before undergoing an arthroplasty was associated with greater risk of prosthetic joint infection. Furthermore, it appears that patients who received arthroscopy within the 3 months before arthroplasty had the highest risk of prosthetic joint infections. Physicians should not only anticipate possible inferior outcomes in patients who have had prior arthroscopy, but also consider delaying the arthroplasty by at least 3 months after the arthroscopy to mitigate the risks of experiencing this costly adverse event.

LEVEL OF EVIDENCE

III.

The In Vitro Efficacy of Doxycycline over Vancomycin and Penicillin in the Elimination of Cutibacterium Acnes Biofilm

Cutibacterium acnes (formerly Propionibacterium acnes) is a significant pathogen in periprosthetic joint infections (PJIs) in total shoulder arthroplasty. Poor outcomes seen in PJIs are due to the established C. acnes bacterial biofilms. The prolonged nature of C. acnes infections makes them difficult to treat with antibiotics. The goal of this study was to determine the relative efficacy of vancomycin compared with penicillin and doxycycline against planktonic and mature biofilms. Clinical isolates from PJI patients as well as a laboratory strain of C. acnes were tested. Planktonic minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were obtained using modified clinical laboratory standard index assays. Biofilm MICs and MBCs were also obtained. The MIC was determined for both using the PrestoBlue viability stain. The MBC was determined using differential reinforced clostridial medium agar plates for colony-forming unit analysis. Using the PrestoBlue viability reagent, the planktonic MIC values for vancomycin were significantly higher than doxycycline. Across 10 strains of C. acnes, all three antibiotics had decreased efficacy when comparing planktonic and biofilm cultures. Although effective antibiotic doses ranged from 1 to 1,000 μg/mL, only doxycycline achieved inhibitory and bactericidal concentrations in all tested strains. Penicillin failed to achieve the minimum biofilm inhibitory concentration (MBIC) in 60% of tested strains, whereas vancomycin failed in 80% of tested strains. Penicillin, doxycycline, and vancomycin have similar abilities in inhibiting C. acnes growth planktonically. The MBIC for doxycycline was within the clinical dosing range, suggesting C. acnes biofilm offers minimal tolerance to these antibiotics. The MBIC for penicillin was within clinical dosing ranges in only 60% of trials, suggesting the relative tolerance of C. acnes to penicillin. The minimum biofilm bactericidal concentration (MBBC) of doxycycline showed efficacy in 90% of trials, whereas penicillin and vancomycin achieved MBBC in 15% of samples.

Risk factors for increased shoulder Cutibacterium acnes burden

Background

Cutibacterium acnes is the primary cause of shoulder surgery infections, but the predisposition to larger skin counts and potentially higher risk for postoperative infection remains unclear. This study aimed to quantify risk factors influencing endogenous C. acnes burden and to compare counts among 4 shoulder sites.

Methods

C. acnes counts were quantified via a detergent scrub technique for 173 participants. Bivariate and multivariable stepwise linear regression statistical analyses were used to investigate the association of sex, age, ethnicity, degree of hirsutism, diabetes, smoking status, body mass index, and location with counts. A separate Wilcoxon rank-sum test was performed analyzing counts of East/Southeast Asians vs. all other ethnicities.

Results

Sex, age, degree of hirsutism, diabetes, smoking status, and body mass index were included in the multivariable stepwise linear regression analysis. The multiple regression analysis isolated individuals <40 years with the highest burden (P = .001). Males had a 191% increase in C. acnes counts compared with females (P = .001). Increased hirsutism was further indicated to be a risk factor for the male sex although not in a dose-dependent manner (P = .027). Wilcoxon rank-sum test results found that East/Southeast Asians had the lowest load (P = .019), although not significant in the multivariate model.

Conclusion

Surgical site C. acnes infections occur more frequently in younger males, and males <40 years with shoulder-specific hirsutism have the highest preoperative burden. East/Southeast Asians have lower raw counts of C. acnes compared with other ethnicities that may be related to less hirsutism.

Calcium sulphate mixed with antibiotics does not decrease efficacy against Cutibacterium acnes (formerly Propionibacterium acnes), in vitro study

Background

This study explored the in vitro efficacy of antibiotics mixed with calcium sulfate (ACS) against Cutibacterium acnes (C. acnes).

Methods

C. acnes isolates from orthopaedic infection sites were tested for antimicrobial susceptibility with ACS. Minimal inhibitory concentrations (MIC) were determined with a gradient diffusion method (Etest® strips).

Results

When tested with Etest®, all 22 isolates were susceptible to penicillin, ceftriaxone, vancomycin, and two were resistant to clindamycin (MICs of 4 and 8 mg/L). Penicillin and rifampin had the largest inhibition zone diameters.

Conclusions

Antibiotics retained activity against C. acnes when mixed with calcium sulfate.

Cutibacterium acnes (formerly Proprionibacterium acnes) and Shoulder Surgery

Infection is a rare but serious complication of shoulder arthroplasty. The most prevalent cause of patient infections is Cutibacterium acnes (formerly Proprionibacterium acnes), a commensal skin bacterial species. Its presentation is often non-specific and can occur long after shoulder arthroplasty, leading to delay in diagnosis. This bacterium is difficult to culture, typically taking 14 to 17 days for a positive culture and often does not exhibit abnormal results on a standard laboratory workup for infection (eg, ESR, CRP, and synovial WBC count). Male patients are at particularly high-risk due to having a greater number of sebaceous follicles than females. While it is difficult to diagnose, early diagnosis can lead to decreased morbidity, appropriate treatment, and improved clinical outcomes. Current options for treatment include antibiotics, one stage implant exchange, or two stage implant exchange, although success rates of each are not currently well described. A better understanding of the prevention, diagnosis, and treatment of C. acnes infection could lead to better patient outcomes from shoulder arthroplasty.

Spondylodiscitis due to Cutibacterium acnes following lumbosacral intradiscal biologic therapy: a case report

A 40-year-old woman with a history of chronic low back pain underwent a fluoroscopically guided intradiscal platelet-rich plasma injection (PRP) at the L5-S1 level. She subsequently developed progressive low back pain, night sweats and decreased ability to ambulate. Laboratory work-up revealed elevated acute phase reactants and imaging revealed L5-S1 intervertebral disc and vertebral end-plate abnormalities highly suggestive of spondylodiscitis. Computed tomography-guided aspiration and biopsy cultures grew Cutibacterium acnes and the patient was subsequently treated with intravenous antibiotics without surgical management. To the best of our knowledge, this is the first published case of lumbar spondylodiscitis following an intradiscal PRP injection, and brings to the forefront several clinically relevant issues including the antimicrobial effects of PRP, the role of C. acnes in spine infections and the ideal treatment protocol for intradiscal biologics in order to minimize morbidity and optimize functional outcomes.

Capsular needle biopsy as a pre-operative diagnostic test for peri-prosthetic shoulder infection

BACKGROUND

Establishing the diagnosis of peri-prosthetic shoulder infection prior to revision shoulder arthroplasty can be difficult. The objectives of the present study were (i) to describe the technique of fluoroscopic capsular needle biopsy for the diagnosis of peri-prosthetic shoulder infection and (ii) to determine the feasibility and preliminary accuracy of the test in a pilot sample of patients undergoing revision shoulder arthroplasty.

METHODS

Eighteen patients, comprising eight females and nine males with a mean age of 61 years (range 37 years to 81 years) underwent capsular needle biopsy during the work-up of suspected chronic arthroplasty-related glenohumeral infection. Intra-operative tissue samples were taken from a minimum of three regions of the joint capsule during revision surgery. Standard serum indices were obtained.

RESULTS

Of 17 patients with possible infection, five had confirmed culture positive infections based on intra-operative biopsies. Of these five patients, four (80%) had positive cultures from fluoroscopic capsular needle biopsy, with matching cultures. There were no complications. No culture-positive patients had elevated serum indices for infection.

CONCLUSIONS

The technique for fluoroscopic capsular needle biopsy appears to be feasible and the preliminary results for this technique appear to be promising, with a sensitivity of 80% and a specificity of 100%.Level of evidence: Level II: diagnostic test.

Reduced Time to Positive Cutibacterium acnes Culture Utilizing a Novel Incubation Technique: A Retrospective Cohort Study

Introduction

Cutibacterium acnes (C. acnes) is a common pathogen in postoperative shoulder infections. The purpose of this study was to evaluate the time to positive cultures for C. acnes and compare our experience before and after implementation of a regulated anaerobic chamber system. We hypothesized that this would reduce the time to identify positive cultures.

Methods

This was a retrospective review of 34 patients with cultures obtained from the shoulder that were positive for C. acnes. The time until positive result was evaluated before and after implementation of a regulated anaerobic incubation chamber.

Results

Following implementation of the regulated anaerobic incubation chamber, the time until C. acnes culture growth significantly decreased from 6.5 days (range 3–10 days) to 4.9 days (range 2.75–10 days) (mean difference: 1.6 days, 95% confidence interval: 1.06–2.66 days; P = .002). True infections had a significantly shorter time to positive culture compared to contaminants (5.5 vs 6.8 days, respectively, P = .003). Increased number of positive culture specimens correlated with a shorter time to positivity (Spearman rank = −0.58, P = .007).

Conclusion

Improved anaerobic culture protocols and techniques may lead to greater accuracy and earlier diagnosis and initiation of treatment of postoperative shoulder infections.

Polymicrobial anaerobic infection with a deep abscess in the supraspinous fossa following a subacromial corticosteroid injection

In September 2015, a male aged 61 years with poorly controlled diabetes (his only medical problem) had left shoulder surgery that included an arthroscopic acromioplasty with debridement of suture material from a rotator cuff repair done 10 years prior. A subacromial corticosteroid injection was given 7 months later for pain and reduced motion. Three weeks later a fulminate infection was evident. Cultures grew Propionibacterium acnes. Treatment included two arthroscopic debridement surgeries and 8 weeks of intravenous antibiotics (primarily daptomycin). Eight weeks after the cessation of the antibiotics, purulence recurred and tissue cultures then grew Staphylococcus epidermidis. Several additional surgeries were needed to control the infection. We failed to recognise that an abscess that extended from the subacromial space across the entire supraspinous fossa. We report this case to alert clinicians that a seemingly innocuous subacromial corticosteroid injection can lead to an atypical infection and also extend into the supraspinous fossa.

Cutibacterium acnes and the shoulder microbiome

BACKGROUND

Advances in DNA sequencing technologies have made it possible to detect microbial genome sequences (microbiomes) within tissues once thought to be sterile. We used this approach to gain insights into the likely sources of Cutibacterium acnes (formerly Propionibacterium acnes) infections within the shoulder.

METHODS

Tissue samples were collected from the skin, subcutaneous fat, anterior supraspinatus tendon, middle glenohumeral ligament, and humeral head cartilage of 23 patients (14 male and 9 female patients) during primary arthroplasty surgery. Total DNA was extracted and microbial 16S ribosomal RNA sequencing was performed using an Illumina MiSeq system. Data analysis software was used to generate operational taxonomic units for quantitative and statistical analyses.

RESULTS

After stringent removal of contamination, genomic DNA from various Acinetobacter species and from the Oxalobacteraceae family was identified in 74% of rotator cuff tendon tissue samples. C acnes DNA was detected in the skin of 1 male patient but not in any other shoulder tissues.

CONCLUSION

Our findings indicate the presence of a low-abundance microbiome in the rotator cuff and, potentially, in other shoulder tissues. The absence of C acnes DNA in all shoulder tissues assessed other than the skin is consistent with the hypothesis that C acnes infections are derived from skin contamination during surgery and not from opportunistic expansion of a resident C acnes population in the shoulder joint.

Propionibacterium acnes Infection of the Shoulder After a Manipulation Under Anesthesia for Stiffness Status Post Open Reduction and Internal Fixation Proximal Humerus: A Case Report

Introduction

Propionibacterium acnes infection has been more frequently recognized as an important cause of post-operative shoulder infection. Infection by this organism is more frequently seen after total shoulder arthroplasty but can also be seen after an open reduction and internal fixation (ORIF) of the proximal humerus. We present a patient with P. acnes infection of the shoulder that only became apparent after he underwent a manipulation under anesthesia for stiffness of the shoulder after an ORIF.

Case Report

Our patient was a 64-year-old male who sustained a proximal humerus fracture after a motorcycle collision and underwent an ORIF of the proximal humerus with plate fixation. Postoperatively, the patient had stiffness of the shoulder so he underwent a manipulation under anesthesia of the shoulder. On post-operative day 5, the patient developed an erythematous area over the incision. This area opened up and began to drain by post-operative day 10. The patient underwent an irrigation and debridement of the shoulder with partial removal of hardware. He was also started on antibiotics and clinically cleared his infection.

Conclusion

Infection by P. acnes can be difficult to diagnose and may present with shoulder stiffness as the only initial symptom. This case is unique as there have not been any documented cases of a latent P. acnes infection presenting after a manipulation under anesthesia of the shoulder. There must be a high clinical suspicion for P. acnes infection in any patient presenting with post-operative stiffness.

Preoperative Doxycycline Does Not Reduce Propionibacterium acnes in Shoulder Arthroplasty

BACKGROUND

Propionibacterium acnes (P. acnes) is the most common bacteria associated with infection after shoulder arthroplasty. These bacteria can be grown on culture of skin after standard preoperative skin preparation and antibiotics. The purpose of this study was to determine whether adding preoperative intravenous doxycycline reduces the prevalence of positive P. acnes cultures of skin and deep tissues at the time of prosthetic joint implantation during shoulder arthroplasty.

METHODS

This was a randomized controlled trial. An a priori power analysis determined that a sample size of 56 patients was necessary. Patients scheduled to undergo shoulder arthroplasty were randomized to receive either standard perioperative cefazolin or a combination of doxycycline and cefazolin. Tissue specimens for culture were then taken from the skin edge, and swabs of the superficial dermal tissue and glenohumeral joint were obtained. All cultures were maintained for 14 days to allow for P. acnes detection. Groups were compared to determine if the addition of doxycycline reduced the rate of culture positivity.

RESULTS

Fifty-six patients were enrolled and randomized. Twenty-one (38%) had ≥1 positive cultures for P. acnes, with no significant difference between the group treated with cefazolin alone (10 [37%] of 27 patients) and the combined doxycycline and cefazolin group (11 [38%] of 29 patients) (p = 0.99). The greatest numbers of culture-positive samples were obtained from the skin (30%), followed by dermal tissue (20%) and the glenohumeral joint (5%). Patients who had ≥1 positive cultures were younger than those who did not (mean age [and standard deviation], 64.9 ± 7.7 versus 69.4 ± 7.7 years; p = 0.041), had a greater tendency to be male (16 [76%] of 21 versus 17 [49%] of 35; p = 0.053), and had a lower Charlson Comorbidity Index (3.35 ± 1.3 versus 4.09 ± 1.4; p = 0.051). There were no significant differences between the culture-positive and culture-negative groups in terms of body mass index (BMI) (p = 0.446) or arthroplasty type, with positive cultures found for 8 of the 29 anatomic shoulder arthroplasty procedures compared with 13 of the 27 reverse shoulder arthroplasty procedures (p = 0.280). There were no doxycycline-related adverse events.

CONCLUSIONS

In this randomized controlled trial, doxycycline did not significantly decrease P. acnes culture positivity of the skin, dermis, or glenohumeral joint of patients undergoing shoulder arthroplasty. The addition of prophylactic intravenous antibiotics to cover P. acnes may not be an effective method to reduce postoperative and periprosthetic shoulder joint infections.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Propionibacterium acnes infections in patients with idiopathic scoliosis: a case-control study and review of the literature

PURPOSE

Surgical site infection (SSI) caused by Propionibacterium acnes is an infrequent but devastating complication after spinal fusion. The purpose of this study was to identify risk factors for SSI with Propionibacterium acnes after spinal fusion for juvenile and adolescent idiopathic scoliosis (JIS and AIS).

METHODS

A case-control study was performed. Each case was matched 2:1 for age, gender and diagnosis. Retrospective chart review was performed to obtain relevant demographic, surgical and clinical data for all cases and controls. Statistical analysis included paired t-test and McNemar test, as well as exact logistic regression and robust regression models.

RESULTS

This study included ten infection cases (eight AIS, two JIS) and 20 controls (16 AIS, four JIS). In total, six infected cases presented within two weeks of the index procedure (acute infection) and four infected cases presented more than one year from the index procedure (delayed infection). The most common presentation for acute infections was wound drainage, while back pain was more common in delayed infections. All infections were successfully treated with surgical irrigation and debridement and postoperative antibiotics. Hardware was removed for patients with delayed infections. The strongest risk factor for infection was increased requirement for blood transfusion, but it did not reach statistical significance.

CONCLUSION

SSI with Propionibacterium acnes is an important complication after spinal fusion for idiopathic scoliosis. These infections can be successfully treated, but larger studies are needed to further identify risk factors and establish standardized guidelines for the treatment and prevention of this complication.

Do Elevated Inflammatory Markers Associate With Infection in Revision Shoulder Arthroplasty?

Background

Serologic erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) measurements, which have been successfully utilized in the lower extremity, are thought to lack adequate sensitivity in the diagnosis of infection after shoulder arthroplasty. The purpose of this study is to determine the diagnostic performance of preoperative white blood cell (WBC) count, ESR, and CRP in the diagnosis of infection in the setting of revision shoulder arthroplasty with the gold standard of infection being defined as a later diagnosis of infection.

Patients and methods

A national insurance database between the years of 2007 and 2015 (PearlDiver, Warsaw, IN) was queried for those patients who underwent revision shoulder arthroplasty using a combination of procedural (common procedural terminology codes 23472 and 23474) and diagnostic codes (International Classification of Diseases [ICD]-9 code 81.97 and equivalent ICD-10 codes). This database contains demographics, laboratory data, and complication data to allow identification of patients with an infection within 1 year postoperatively.

Results

The database contained 1392 patients who met criteria. Among these, the best diagnostic performance was with a combined test which was positive if CRP, ESR, or WBC was positive with a sensitivity of 7% to 42%, a specificity of 92%, a positive predictive value of 8% to 45%, a negative predictive value of 91%, and an accuracy of 84% to 85%. On multivariate analyses, predictors included an abnormal ESR (odds ratio 2.4, P = .05) and male gender (3.8, <.001).

Conclusions

Those patients with an abnormal preoperative ESR have significantly increased odds of a subsequent infection following revision shoulder arthroplasty. ESR, CRP, and WBC in combination are specific but insensitive. Level of Evidence: Diagnostic, Level III

Two-stage revision for infected shoulder arthroplasty

BACKGROUND

Periprosthetic shoulder infections (PSIs) are challenging to treat and often result in significant patient morbidity. Without a standardized treatment protocol, PSIs are often managed similarly to periprosthetic hip and knee infections. Because 2-stage revision is the gold standard for treating periprosthetic hip and knee infections, we performed a case series and literature review to determine its effectiveness in PSIs.

METHODS

We identified 19 patients (14 men) from our institution who were treated with a 2-stage revision after presenting with a PSI. Mean patient age was 63 ± 9 years, and average body mass index was 30.8 ± 5.8. The average time from the index arthroplasty to treatment was 40 months, 8 of 13 positive cultures were Propionibacterium acnes, and 9 of 19 patients had multiple shoulder operations before presenting with infection. Minimum follow-up for all patients was 2 years.

RESULTS

After a mean follow-up of 63 months (range, 25-184 months), 15 of 19 patients in our study were successfully treated for PSI. Average postoperative American Shoulder and Elbow Surgeons (ASES) Shoulder Assessment score was 69 (range, 32-98) and average postoperative forward elevation was significantly increased from 58° to 119° (P < .001). The incidence of recurrent infection was 26%. The rate of noninfection complications was 16%, for a total complication rate of 42%.

CONCLUSION

In patients with PSIs, especially those with intractable, chronic infections, a 2-stage revision represents a viable treatment option for eradicating infection and restoring function. However, it is important to recognize the risk of recurrent infection and postoperative complications in this challenging patient population.

Incidence of Propionibacterium acnes in initially culture-negative thioglycollate broths-a prospective cohort study at a Danish University Hospital

The aim of this study was to prospectively investigate the incidence of Propionibacterium acnes in thioglycollate broths reported as culture-negative at the Department of Clinical Microbiology, Rigshospitalet, to evaluate whether 5 days of incubation was enough to find all relevant cases. Five hundred thioglycollate broths reported as culture-negative after 5 days were consecutively collected and incubated for at least a further 9 days (at least 14 days of incubation in total). Only tissue samples from sterile sites of the body (n = 298), bone tissue (n = 197) and foreign material (n = 5) were included in this study. Samples were divided into two groups: infected group and control group. This made it possible to compare findings between groups, thereby making it possible to estimate the level of true-positive findings and contamination. Samples from 296 participants were included in this study. After exclusion criteria were met, P. acnes was cultured from ten out of 151 patients (6.6%) in the infected group and from one out of 138 participants (0.7%) in the control group. This resulted in more findings of P. acnes in the infected group on day 14 than on day 5 (p 0.002). Furthermore, P. acnes was cultured more often from bone tissue and tissue surrounding foreign materials on day 14 than on day 5 (p 0.04). Clinical microbiology laboratories should consider incubating thioglycollate broths for at least 14 days to find all relevant cases of P. acnes, especially when it comes to bone tissue and tissue surrounding foreign materials.

Ten questions on prosthetic shoulder infection

Prosthetic shoulder infection can cause significant morbidity secondary to pain and stiffness. Symptoms may be present for years before diagnosis because clinical signs are often absent and inflammatory markers may be normal. An emerging common culprit, Propionibacterium acnes, is hard to culture and so prolonged incubation is necessary. A negative culture result does not always exclude infection and new synovial fluid biochemical markers such as α defensin are less sensitive than for lower limb arthroplasty. A structured approach is necessary when assessing patients for prosthetic shoulder joint infection. This includes history, examination, serum inflammatory markers, plain radiology and aspiration and/or biopsy. A classification for the likelihood of prosthetic shoulder infection has been described based on culture, pre-operative and intra-operative findings. Treatment options include antibiotic suppression, debridement with component retention, one-stage revision, two-stage revision and excision arthroplasty. Revision arthroplasty is associated with the best outcomes.

Animal Models of Implant-Related Low-Grade Infections. A Twenty-Year Review

The demand for joint replacement and surgical treatment is continuously increasing, thus representing a clinical burden and a cost for the healthcare system. Among several pathogens involved in implant-related infections, staphylococci account for the two-thirds of clinically isolated bacteria. Despite most of them are highly virulent microorganisms (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa), low virulent bacteria (Staphylococcus epidermidis, Propionibacterium acnes) are responsible for delayed, low-grade infections without specific clinical signs and hardly distinguishable from aseptic prosthetic failure. Therefore, there is a real need to study the pathogenesis of orthopedic infections through in vivo animal models. The present review of the literature provides a 20-year overview of animal models of acute, subclinical or chronic orthopedic infections according to the pathogen virulence and inocula. Through this analysis, a great variety of conditions in terms of bacterial strains and inocula emerged, thus encouraging the development of more reproducible in vivo studies to provide relevant information for a translational approach to humans.

Propionibacterium acnes infection after shoulder surgery

Propionibacterium acnes has been implicated as a cause of infection following shoulder surgery, may occur up to 2 years after the index operation and has been shown to be responsible for up to 56% of shoulder infections after orthopedic implant. Male patients within the population undergoing shoulder surgery are particularly at risk, especially if their shoulder surgery involved prosthesis or was posttraumatic. P. acnes infection can be difficult to diagnose clinically and laboratory techniques require prolonged and specialized cultures. Usual inflammatory markers are not raised in infection with this low virulence organism. Delayed diagnosis with P. acnes infection can result in significant morbidity prior to prosthesis failure. Early diagnosis of P. acnes infection and appropriate treatment can improve clinical outcomes. It is important to be aware of P. acnes infection in shoulder surgery, to evaluate risk factors, to recognize the signs of P. acnes infection, and to promptly initiate treatment. The signs and symptoms of P. acnes infection are described and discussed. Data were collected from PubMed™, Web of Science, and the NICE Evidence Healthcare Databases - AMED (Ovid), BNI (Ovid), CINAHL (EBSCO), Embase (Ovid), HMIC: DH-Data and Kings Fund (Ovid), Medline (Ovid), and PsycINFO (Ovid). The search terms used were "P. acnes," "infection," "shoulder," and "surgery." In this review, we summarize the current understanding of the prevention and management of P. acnes infection following shoulder surgery.