Cutibacterium acnes: a threat to shoulder surgery or an orthopedic red herring?

Synovial Fluid Cutibacterium acnes Antigen Is Detected Among Shoulder Samples with High Inflammation and Early Culture Growth

BACKGROUND

An emerging paradigm suggests that positive Cutibacterium acnes shoulder cultures can result from either true infection or contamination, with true infections demonstrating a host inflammatory response and early culture growth. This clinical retrospective study examines the relationship between C. acnes antigen, C. acnes culture results, and inflammation.

METHODS

From January 2021 to July 2023, 1,365 periprosthetic synovial fluid samples from 347 institutions were tested for shoulder infection at a centralized clinical laboratory. A biomarker scoring system based on the 2018 International Consensus Meeting (ICM) definition was utilized to assign each sample an inflammation score. Associations between inflammation, culture results, and C. acnes antigen results were assessed utilizing cluster and correlation analyses.

RESULTS

Of 1,365 samples, 1,150 were culture-negative and 215 were culture-positive (94 C. acnes and 121 other organisms). Among the 94 C. acnes culture-positive samples, unsupervised clustering revealed 2 distinct sample clusters (silhouette coefficient, 0.83): a high-inflammation cluster (n = 67) and a low-inflammation cluster (n = 27). C. acnes antigen levels demonstrated moderate-strong positive correlation with inflammation (Spearman ρ, 0.60), with 166-fold higher levels of C. acnes antigen in high-inflammation samples (16.6 signal/cutoff [S/CO]) compared with low-inflammation samples (0.1 S/CO) (p < 0.0001). The days to C. acnes culture positivity demonstrated weak-inverse correlation with inflammation (Spearman ρ = -0.38), with 1.5-fold earlier growth among the 67 high-inflammation samples (6.7 compared with 10.4 days; p < 0.0001). Elevated C. acnes antigen was observed in only 4 (0.38%) of 1,050 low-inflammation culture-negative samples and in only 5 (4.9%) of 103 high-inflammation non- C. acnes -positive cultures. However, 19.0% of high-inflammation, culture-negative samples demonstrated elevated C. acnes antigen.

CONCLUSIONS

Synovial fluid C. acnes antigen was detected among shoulder samples with high inflammation and early culture growth, supporting the emerging paradigm that these samples represent true infection. Future research should explore antigen testing to differentiate contamination from infection and to identify culture-negative C. acnes infections.

LEVEL OF EVIDENCE

Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Vancomycin Soaking to Reduce Intraoperative Contamination by Cutibacterium acnes During the Latarjet Procedure

BACKGROUND

Postoperative infection after the Latarjet procedure, ranging from 1% to 6%, can compromise the functional outcome of young athletes. Cutibacterium acnes is a main pathogen as a consequence of an intraoperative contamination.

PURPOSE

To evaluate intraoperative contamination with C. acnes and the effectiveness of the local application of vancomycin during the Latarjet procedure.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This was a single-center study including 75 patients (mean age, 26 years; range, 15-55 years) operated on for anterior shoulder instability with the primary open Latarjet procedure; they underwent the same protocol of skin preparation and preoperative prophylactic antibiotics. Three groups of 25 patients were created and divided sequentially, without the results of each group being known before the end of the study: group A (5 mg/mL of vancomycin), group B (20 mg/mL of vancomycin), and group C (control group with no vancomycin). Swab samples of the coracoid were taken before sectioning the coracoid process (time 1) and after its preparation (time 2). The coracoid was then wrapped in gauze impregnated with different concentrations of vancomycin, except for group C. A final sample (time 3) was taken before screwing the bone block onto the glenoid. All samples were cultured for 21 days, and patients underwent clinical and radiological follow-up for 6 months.

RESULTS

The C. acnes contamination rates at times 1, 2, and 3 were 25%, 44%, and 45%, respectively, without significant difference. There was no significant difference between groups A and B with respect to the number of positive cultures at each time point. Of 9 positive cultures at time 1, all were still positive at time 3 in group A, whereas 3 of 5 were negative in group B (P = .027). The rate of C. acnes at time 3 in the control group was higher than that in the 2 other groups (68% vs 44% for group A and 20% for group B; P = .003). Body mass index was the only prognostic factor for a C. acnes-positive culture (26.05 ± 3.39 vs 23.34 ± 2.33; P = .018). No clinical infection was reported at the 6-month postoperative follow-up.

CONCLUSION

The rate of C. acnes contamination ranged from 25% to 68% during the open Latarjet procedure in young athletes. Vancomycin reduced the bacterial contamination when it was used at high concentrations in a gauze wrap on the coracoid. The type of C. acnes detected and its clinical implications remain to be studied.

Hydrogen Peroxide May Reduce the Risk for Revision Surgery and Infection in Primary Shoulder Arthroplasty: Two-year Follow-up From a Prospective, Blinded, Controlled Trial

BACKGROUND

The purpose of this study was to determine whether the addition of hydrogen peroxide to the preoperative skin preparation for primary total shoulder arthroplasty is associated with a difference in patient-reported outcomes, risk for postoperative infection, and risk for revision surgery at a minimum of 2-year follow-up.

METHODS

This was a prospective, blinded, and controlled trial, which included a consecutive series of patients undergoing primary shoulder arthroplasty. The control group underwent standard sterile skin preparation using ethyl alcohol and ChloraPrep applicators, and the peroxide group had the same preparation with the addition of hydrogen peroxide between the alcohol and ChloraPrep applications. We then compared patient-reported outcome scores (American Shoulder and Elbow Surgeons Shoulder Score [ASES], simple shoulder test [SST], visual analog scale [VAS]), infections, and revision surgeries between the two groups at 2-year follow-up.

RESULTS

Of the 61 patients included in the original study, 52 of 58 (85%) living patients agreed to participate in this study. No preoperative differences were observed between groups. No difference was observed in ASES, SST, or VAS scores at 2 years. More revision surgeries were done in the control group (7 versus 2, P = 0.268) and Cutibacterium acnes infections (2 versus 0, P = 0.168).

CONCLUSION

The addition of hydrogen peroxide to the preoperative skin preparation before primary shoulder arthroplasty is safe, and additional research is warranted to investigate whether it may decrease the risk for revision surgery and postoperative C acnes infection.

LEVEL OF EVIDENCE

III.

Operating Room Air May Harbor Pathogens: The Role of an Ultraviolet Air Filtration Unit

BACKGROUND

One important factor for the prevention of surgical site infections is ultraclean air in the operating room (OR). Still, the direct sterilization potential of most technologies, especially in a dynamic clinical setting, is not well understood. We aimed to determine and compare the microbial presence from the inlet and outlet flow of a filtration unit with crystalline ultraviolet-C (C-UVC) light.

METHODS

A prospective study was conducted at a single institution, where primary total joint arthroplasty and spine surgeries were performed. The OR was fitted with a positive ventilation system. In addition, a filtration unit with a C-UVC sterilizing light was placed in the OR. The inlet and outlet air flows were swabbed simultaneously and compared. Swabs were processed for culture and next-generation sequencing.

RESULTS

The mean length of the surgical procedures sampled was 68 ± 13 minutes. Overall, 19 out of 200 (9.5%) swabs isolated microorganisms. Inlet air swabs were positive at a higher rate (16 versus 3%; P < .01) compared to the outlet air swabs. A wide variety of Gram-positive, Gram-negative, and anaerobic bacteria were isolated, but fungi were only recovered from inlet air swabs. The detection of microorganisms was also higher when more door openings were performed (32.5 ± 7.1 versus 27.9 ± 5.6; P < .01).

CONCLUSIONS

Air swabs mainly isolated microorganisms from the inlet flow to the filtration unit with a C-UVC light. The sterilizing unit counteracted factors affecting the air quality in the OR, namely door openings, surgical personnel, and tissue combustion.

2023 Neer Award for Basic Science: Genetics of Cutibacterium acnes in revision shoulder arthroplasty: a large-scale bacterial whole-genome sequencing study

BACKGROUND

Cutibacterium acnes is the bacterium most commonly responsible for shoulder periprosthetic joint infection (PJI) and is often cultured from samples obtained at the time of revision for failed shoulder arthroplasty. We sought to determine whether these bacteria originate from the patient or from exogenous sources. We also sought to identify which C. acnes genetic traits were associated with the development of shoulder PJI.

METHODS

We performed bacterial whole-genome sequencing of C. acnes from a single-institution repository of cultures obtained before or during primary and revision shoulder arthroplasty and correlated the molecular epidemiology and genetic content of strains with clinical features of infection.

RESULTS

A total of 341 isolates collected over a 4-year period from 88 patients were sequenced. C. acnes cultured from surgical specimens demonstrated significant similarity to the strains colonizing the skin of the same patient (P < .001). Infrequently, there was evidence of strains shared across unrelated patients, suggesting that exogenous sources of C. acnes culture-positivity were uncommon. Phylotypes IB and II were modestly associated with clinical features of PJI, but all phylotypes appeared inherently capable of causing disease. Chronic shoulder PJI was associated with the absence of common C. acnes genes involved in bacterial quorum-sensing (luxS, tqsA).

CONCLUSION

C. acnes strains cultured from deep intraoperative sources during revision shoulder arthroplasty demonstrate strong genetic similarity to the strains colonizing a patient's skin. Some phylotypes of C. acnes commonly colonizing human skin are modestly more virulent than others, but all phylotypes have a capacity for PJI. C. acnes cultured from cases of PJI commonly demonstrated genetic hallmarks associated with adaptation from acute to chronic phases of infection. This is the strongest evidence to date supporting the role of the patient's own, cutaneous C. acnes strains in the pathogenesis of shoulder arthroplasty infection. Our findings support the importance of further research focused on perioperative decolonization and management of endogenous bacteria that are likely to be introduced into the arthroplasty wound at the time of skin incision.

Detection of Cutibacterium (Propionibacterium) acnes in orthopaedic surgery: serious problem or contamination?

PURPOSE

Bone and joint infections are an important and increasing problem. Whether intraoperatively detected bacteria should be considered relevant or not is often difficult to assess. This retrospective cohort study analyzes the relevance of C. acnes cultured from deep intraoperative specimens.

METHODS

All deep tissue samples collected intraoperatively between 2015 and 2020 from a quartiary care provider were evaluated for detection of C. acnes and its therapeutical consequences. Infection rates were determined according to a standardized definition and protocol and analyzed in dependence of patient's demographic data (age and gender), operative parameters (type of surgery, body region/location of surgery, and impression of the surgeon), and initiated therapy.

RESULTS

In 270 cases of more than 8500 samples, C. acnes was detected. In 30%, the detection was considered an infection. The number of samples taken and tested positive for C. acnes correlated significantly with its classification as a cause of infection. If more than one sample of the patient was positive, the detection was significantly more likely to be treated as infection (p < 0.001). In 76% of cases, a consultation to the infectious diseases (ID) department took place regarding the classification of the pathogen detection and the therapy to be carried out. Almost all of the tested isolates demonstrated the wild-type susceptibility for penicillin and clindamycin.

CONCLUSION

Intraoperative detection of skin-colonizing bacteria such as C. acnes is not always synonymous with infection. In particular, if other examination results contradict an infection (pathological sample without evidence of an infectious event, detection of malignant cells, etc.), the situation must be considered in a very differentiated manner. Interdisciplinary boards, for example, are suitable for this purpose. Care should be taken to obtain a sufficiently large number of tissue samples for microbiological examination to be able to better classify the result.

Effect of making skin incision with electrocautery on positive Cutibacterium acnes culture rates in shoulder arthroplasty: a prospective randomized clinical trial

BACKGROUND

Cutibacterium acnes remains the most commonly detected organism in shoulder arthroplasty. C acnes infection is thought to occur during shoulder arthroplasty through contamination of the surgical field with C acnes from the incised dermis. The purpose of this study was to examine whether using electrocautery for making skin incisions would decrease C acnes culture rates at the incised dermis compared to using scalpels during shoulder arthroplasty.

METHODS

Patients undergoing primary shoulder arthroplasty were randomized into 2 groups, electrocautery vs. scalpel incision group. All patients received a standard preoperative antiseptic preparation including chlorhexidine gluconate showers, intravenous antibiotic administration, and topical application of hydrogen peroxide, povidone iodine, isopropyl alcohol, and DuraPrep. Cultures were obtained from the incised dermal edge immediately after skin incision and later from surgeon's gloves and forceps immediately prior to humeral component implantation. The primary outcome was positive C acnes culture rates compared between the groups.

RESULTS

A total of 64 patients (32 in each group) were enrolled. There were 24 males in each group. Regarding dermis cultures, 10 patients (31%) in the scalpel group were positive with 8 of them positive for C acnes, whereas no patients in the electrocautery group were positive (P < .001). Regarding glove cultures, the electrocautery group had 8 patients positive C acnes, while the scalpel group had 8 (P = .777). Regarding forceps cultures, the electrocautery group had 4 patients positive for C acnes, and the scalpel group had 6 (P = .491). All positive cultures were exclusively from male patients. There were no wound complications or infection in the electrocautery group while the scalpel group had 1 acute postoperative infection.

CONCLUSIONS

Making skin incisions using electrocautery resulted in 0 C acnes culture at the incised dermis, suggesting its potential effect against C acnes. However, despite this initial antibacterial effect, C acnes still appeared on surgeon's gloves and forceps during surgery of male patients. All positive cultures were from male patients, suggesting that the source of C acnes was specifically related to the male body. While the study hypothesis was supported by the results, the present study also raises new questions and calls for further research.

Next-generation Sequencing Results Require Higher Inoculum for Cutibacterium acnes Detection Than Conventional Anaerobic Culture

BACKGROUND

Cutibacterium acnes has been described as the most common causative microorganism in prosthetic shoulder infections. Conventional anaerobic culture or molecular-based technologies are usually used for this purpose, but little to no concordance between these methodologies (k = 0.333 or less) has been observed.

QUESTIONS/PURPOSES

(1) Is the minimum C. acnes load for detection higher for next-generation sequencing (NGS) than for anaerobic conventional culture? (2) What duration of incubation is necessary for anaerobic culture to detect all C. acnes loads?

METHODS

Five C. acnes strains were tested for this study: Four strains were causing infection and were isolated from surgical samples. Meanwhile, the other was a reference strain commonly used as a positive and quality control in microbiology and bioinformatics. To create inoculums with varying degrees of bacterial load, we began with a standard bacterial suspension at 1.5 x 10 8 colony-forming units (CFU)/mL and created six more diluted suspensions (from 1.5 x 10 6 CFU/mL to 1.5 x 10 1 CFU/mL). Briefly, to do so, we transferred 200 µL from the tube with the highest inoculum (for example, 1.5 x 10 6 CFU/mL) to the following dilution tube (1.5 x 10 5 CFU/mL; 1800 µL of diluent + 200 µL of 1.5 x 10 6 CFU/mL). We serially continued the transfers to create all diluted suspensions. Six tubes were prepared per strain. Thirty bacterial suspensions were tested per assay. Then, 100 µL of each diluted suspension was inoculated into brain heart infusion agar with horse blood and taurocholate agar plates. Two plates were used per bacterial suspension in each assay. All plates were incubated at 37°C in an anaerobic chamber and assessed for growth after 3 days of incubation and daily thereafter until positive or Day 14. The remaining volume of each bacterial suspension was sent for NGS analysis to identify bacterial DNA copies. We performed the experimental assays in duplicate. We calculated mean DNA copies and CFUs for each strain, bacterial load, and incubation timepoint assessed. We reported detection by NGS and culture as a qualitative variable based on the identification or absence of DNA copies and CFUs, respectively. In this way, we identified the minimum bacterial load detected by NGS and culture, regardless of incubation time. We performed a qualitative comparison of detection rates between methodologies. Simultaneously, we tracked C. acnes growth on agar plates and determined the minimum incubation time in days required for CFU detection in all strains and loads examined in this study. Growth detection and bacterial CFU counting were performed by three laboratory personnel, with a high intraobserver and interobserver agreement (κ > 0.80). A two-tailed p value below 0.05 was considered statistically significant.

RESULTS

Conventional cultures can detect C. acnes at a load of 1.5 x 10 1 CFU/mL, whereas NGS can detect bacteria when the concentration was higher, at 1.5 x 10 2 CFU/mL. This is represented by a lower positive detection proportion (73% [22 of 30]) for NGS than for cultures (100% [30 of 30]); p = 0.004). By 7 days, anaerobic cultures were able to detect all C. acnes loads, even at the lowest concentrations.

CONCLUSION

When NGS is negative and culture is positive for C. acnes , there is likely a low bacterial load. Holding cultures beyond 7 days is likely unnecessary.

CLINICAL RELEVANCE

This is important for treating physicians to decide whether low bacterial loads necessitate aggressive antibiotic treatment or whether they are more likely contaminants. Cultures that are positive beyond 7 days likely represent contamination or bacterial loads even below the dilution used in this study. Physicians may benefit from studies designed to clarify the clinical importance of the low bacteria loads used in this study at which both methodologies' detection differed. Moreover, researchers might explore whether even lower C. acnes loads have a role in true periprosthetic joint infection.

Phenotypic and Genotypic Characterization of Cutibacterium acnes Isolated from Shoulder Surgery Reveals Insights into Genetic Diversity

Specific virulence factors that likely influence C. acnes invasion into deep tissues remain to be elucidated. Herein, we describe the frequency of C. acnes identification in deep tissue specimens of patients undergoing clean shoulder surgery and assess its phenotypic and genetic traits associated with virulence and antibiotic resistance patterns, compared with isolates from the skin of healthy volunteers. Multiple deep tissue specimens from the bone fragments, tendons, and bursa of 84 otherwise healthy patients undergoing primary clean-open and arthroscopic shoulder surgeries were aseptically collected. The overall yield of tissue sample cultures was 21.5% (55/255), with 11.8% (30/255) identified as C. acnes in 27.3% (23/84) of patients. Antibiotic resistance rates were low, with most strains expressing susceptibility to first-line antibiotics, while a few were resistant to penicillin and rifampicin. Phylotypes IB (73.3%) and II (23.3%) were predominant in deep tissue samples. Genomic analysis demonstrated differences in the pangenome of the isolates from the same clade. Even though strains displayed a range of pathogenic markers, such as biofilm formation, patients did not evolve to infection during the 1-year follow-up. This suggests that the presence of polyclonal C. acnes in multiple deep tissue samples does not necessarily indicate infection.

The value of sonication on orthopaedic implants in an everyday clinical setting - an exploratory study

BACKGROUND

Sonication of removed orthopaedic implants in suspected implant-associated infections (IAI) is widely applied internationally. However, evaluation of the utility of sonication on all implants removed in everyday standard practice is scarce. This exploratory study was performed to evaluate the application of sonication fluid (SF) culture on removed orthopaedic implants, irrespective of the reason for removal.

METHODS

Out of 100 removed orthopaedic implants collected between August 2019 and September 2020, 77 implants with availability of concurrent tissue culture samples were included in the study. Removed implants were categorized into a confirmed or suspected IAI group and a presumed aseptic group based on pre-operative diagnosis by the responsible surgeon. Implants were sonicated and SF culture performed under both aerobic and anaerobic conditions. The significance of all bacterial isolates was evaluated based on the CFU/mL cut-offs of the EBJIS guidelines, except for C. acnes where additional investigations were performed.

RESULTS

The results of SF culture in the two groups were compared with their corresponding tissue cultures. Out of the 12 cases in the confirmed/suspected IAI group, SF culture was positive in 11 cases and had increased diagnostic yield in two (17%) cases compared to tissue culture. Increased diagnostic yield of SF compared to tissue culture was seen in seven (11%) of the 65 implants in the presumed aseptic group. If growth of Cutibacterium species isolates were interpreted based on EBJIS cut-off for SF culture instead of the study-specific criteria, then two isolates considered to represent infection might have been missed while three other isolates considered contaminants would have fallen under the 'infection confirmed' category in the EBJIS guidelines.

CONCLUSION

Sonication with SF culture has increased diagnostic yield compared to tissue cultures in all implants irrespective of reason for removal. However, positive SF cultures with Cutibacterium species should always be interpreted with extreme care.

The Diagnostic Potential of the Human Blood Microbiome: Are We Dreaming or Awake?

Human blood has historically been considered a sterile environment. Recently, a thriving microbiome dominated by Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes phyla was detected in healthy blood. The localization of these microbes is restricted to some blood cell populations, particularly the peripheral blood mononuclear cells and erythrocytes. It was hypothesized that the blood microbiome originates from the skin-oral-gut axis. In addition, many studies have evaluated the potential of blood microbiome dysbiosis as a prognostic marker in cardiovascular diseases, cirrhosis, severe liver fibrosis, severe acute pancreatitis, type 2 diabetes, and chronic kidney diseases. The present review aims to summarize current findings and most recent evidence in the field.

Shotgun sequencing of sonication fluid for the diagnosis of orthopaedic implant-associated infections with Cutibacterium acnes as suspected causative agent

Orthopaedic implant-associated infections (OIAIs) due to Cutibacterium acnes can be difficult to diagnose. The aim of this pilot study was to determine if metagenomic next-generation sequencing (mNGS) can provide additional information to improve the diagnosis of C. acnes OIAIs. mNGS was performed on sonication fluid (SF) specimens derived from 24 implants. These were divided into three groups, based on culture results: group I, culture-negative (n = 4); group II, culture-positive for C. acnes (n = 10); and group III, culture-positive for other bacteria (n = 10). In group I, sequence reads from C. acnes were detected in only one SF sample, originating from a suspected case of OIAIs, which was SF and tissue culture-negative. In group II, C. acnes sequences were detected in 7/10 samples. In group III, C. acnes sequence reads were found in 5/10 samples, in addition to sequence reads that matched the bacterial species identified by culture. These samples could represent polymicrobial infections that were missed by culture. Taken together, mNGS was able to detect C. acnes DNA in more samples compared to culture and could be used to identify cases of suspected C. acnes OIAIs, in particular regarding possible polymicrobial infections, where the growth of C. acnes might be compromised due to a fast-growing bacterial species. However, since SF specimens are usually low-biomass samples, mNGS is prone to DNA contamination, possibly introduced during DNA extraction or sequencing procedures. Thus, it is advisable to set a sequence read count threshold, taking into account project- and NGS-specific criteria.

Update on Shoulder Arthroplasties with Emphasis on Imaging

Shoulder pain and dysfunction may significantly impact quality of life. If conservative measures fail, advanced disease is frequently treated with shoulder arthroplasty, which is currently the third most common joint replacement surgery following the hip and knee. The main indications for shoulder arthroplasty include primary osteoarthritis, post-traumatic arthritis, inflammatory arthritis, osteonecrosis, proximal humeral fracture sequelae, severely dislocated proximal humeral fractures, and advanced rotator cuff disease. Several types of anatomic arthroplasties are available, such as humeral head resurfacing and hemiarthroplasties, as well as total anatomic arthroplasties. Reverse total shoulder arthroplasties, which reverse the normal ball-and-socket geometry of the shoulder, are also available. Each of these arthroplasty types has specific indications and unique complications in addition to general hardware-related or surgery-related complications. Imaging-including radiography, ultrasonography, computed tomography, magnetic resonance imaging, and, occasionally, nuclear medicine imaging-has a key role in the initial pre-operative evaluation for shoulder arthroplasty, as well as in post-surgical follow-up. This review paper aims to discuss important pre-operative imaging considerations, including rotator cuff evaluation, glenoid morphology, and glenoid version, as well as to review post-operative imaging of the various types of shoulder arthroplasties, to include normal post-operative appearances as well as imaging findings of complications.

The Choice of Antibiotic Prophylaxis Influences the Infection Reoperation Rate in Primary Shoulder Arthroplasty: Analysis From the Swedish Shoulder Arthroplasty Register

BACKGROUND

Periprosthetic joint infection is a serious complication and a major reason for revision surgery after primary shoulder arthroplasty. The prophylactic antibiotics for primary shoulder arthroplasty that have predominantly been used in Sweden are cloxacillin and clindamycin. To address Cutibacteriumacnes , benzylpenicillin has recently increasingly been added to cloxacillin, but it is unclear which antibiotic prophylaxis regimen is the most effective to prevent periprosthetic joint infection.

QUESTIONS/PURPOSES

After controlling for baseline differences among patients such as age, gender, previous surgery, cement fixation, and arthroplasty type, was the risk of reoperation for infection higher in patients who received cloxacillin than in those who received clindamycin or the combination of benzylpenicillin and cloxacillin?

METHODS

Data from the Swedish Shoulder Arthroplasty Register were used for this study. The inclusion criterion was registered antibiotic prophylaxis in primary arthroplasty. Between January 1, 1999, and December 31, 2019, 22,470 primary shoulder arthroplasties, including total shoulder, hemiarthroplasty, and reverse shoulder arthroplasties, were entered into the Swedish Shoulder Arthroplasty Register. Reporting of antibiotic prophylaxis to the register was introduced on January 1, 2013. Since then, the completeness of information on the type of antibiotic prophylaxis in the reports has been 85.3%. Consequently, 10,706 arthroplasties were eligible and fulfilled the inclusion criterion of reported antibiotic prophylaxis. A further 129 were excluded because of unusual prophylaxis regimens, leaving 10,577 shoulder arthroplasties for analysis. The Swedish Shoulder Arthroplasty Register gathers information from all 60 hospitals performing shoulder arthroplasty in Sweden, and through a comparison with the National Patient Register, it has been estimated that more than 90% of all primary shoulder arthroplasties and shoulder reoperations are reported to the register. The age of the study population ranged between 16 and 98 years; the mean age at the primary surgery was 70 ± 10 years for the entire cohort, with a mean age of 67 ± 10 years and 72 ± 9 years for men and women, respectively. The mean observation period was 989 ± 669 days. From 2013 to 2019, there was a clear change in prophylaxis; in particular, the use of the combination of benzylpenicillin and cloxacillin increased dramatically and the use of cloxacillin alone decreased. Clindamycin prophylaxis increased moderately. The primary study endpoint was reported reoperation for infection. In the register, this is defined as repeat procedures of any kind, including biopsy, lavage of the joint, or revision, defined as secondary surgery in which a component was exchanged, removed, or added. To compare the reoperation rate in relation to the different antibiotics used, which changed over time, we controlled for age, gender, previous surgery, cement fixation, and arthroplasty type using a Cox proportional hazards model.

RESULTS

When adjusting for age, gender, previous surgery, cement fixation, and arthroplasty type, cloxacillin prophylaxis was associated with an increased relative risk of reoperation for infection compared with the combination of cloxacillin and benzylpenicillin (hazard ratio [HR] 2.40 [95% confidence interval (CI) 1.35 to 4.25]; p = 0.003) and compared with clindamycin alone (HR 1.78 [95% CI 1.11 to 2.85]; p = 0.02). No difference was found between the cloxacillin and benzylpenicillin combination and clindamycin (HR 0.74 [95% CI 0.42 to 1.32]; p = 0.31).

CONCLUSION

Our results indicate that prophylaxis against C. acnes may be warranted in shoulder arthroplasty. Because the absolute number of infections was low and infections could have been underreported to the register, our results should be interpreted with caution. There is no available information about the causative microorganisms. The study lays the groundwork for further investigations of antibiotic prophylaxis regimens in shoulder arthroplasty. Because large randomized controlled trials would be impractical to perform, prospective register-based randomized controlled studies might be a viable method.

LEVEL OF EVIDENCE

Level Ⅲ, therapeutic study.

Genomics of Invasive Cutibacterium acnes Isolates from Deep-Seated Infections

Cutibacterium acnes, formerly known as Propionibacterium acnes, is a commensal of the human pilosebaceous unit but also causes deep-seated infection, especially in the context of orthopedic and neurosurgical foreign materials. Interestingly, little is known about the role of specific pathogenicity factors for infection establishment. Here, 86 infection-associated and 103 commensalism-associated isolates of C. acnes were collected from three independent microbiology laboratories. We sequenced the whole genomes of the isolates for genotyping and a genome-wide association study (GWAS). We found that C. acnes subsp. acnes IA1 was the most significant phylotype among the infection isolates (48.3% of all infection isolates; odds ratio [OR] = 1.98 for infection). Among the commensal isolates, C. acnes subsp. acnes IB was the most significant phylotype (40.8% of all commensal isolates; OR = 0.5 for infection). Interestingly, C. acnes subsp. elongatum (III) was rare overall and did not occur at all in infection. The open reading frame-based GWAS (ORF-GWAS) did not show any loci with a strong signal for infection association (no P values of ≤0.05 after adjustment for multiple testing; no logarithmic OR [logOR] of ≥|2|). We concluded that all subspecies and phylotypes of C. acnes, possibly with the exception of C. acnes subsp. elongatum, are able to cause deep-seated infection given favorable conditions, most importantly related to inserted foreign material. Genetic content appears to have a small effect on the likelihood of infection establishment, and functional studies are needed to understand the individual factors contributing to deep-seated infections caused by C. acnes. IMPORTANCE Opportunistic infections emerging from human skin microbiota are of ever-increasing importance. Cutibacterium acnes, being abundant on the human skin, may cause deep-seated infections (e.g., device-associated infections). Differentiation between invasive (i.e., clinically significant) C. acnes isolates and sole contaminants is often difficult. Identification of genetic markers associated with invasiveness not only would strengthen our knowledge related to pathogenesis but also could open ways to selectively categorize invasive and contaminating isolates in the clinical microbiology lab. We show that in contrast to other opportunistic pathogens (e.g., Staphylococcus epidermidis), invasiveness is apparently a broadly distributed ability across almost all C. acnes subspecies and phylotypes. Thus, our work strongly supports an approach in which clinical significance is judged from clinical context rather than by detecting specific genetic traits.

A high prevalence of Cutibacterium acnes infections in scoliosis revision surgery, a diagnostic and therapeutic dilemma

PURPOSE

To investigate if serum inflammatory markers or nuclear imaging can accurately diagnose a chronic spinal instrumentation infection (SII) prior to surgery.

METHODS

All patients who underwent revision of spinal instrumentation after a scoliosis correction between 2017 and 2019, were retrospectively evaluated. The diagnostic accuracy of serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR), ¹⁸F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) and Technetium-99m-methylene diphosphonate (99mTc-MDP) 3-phase bone scintigraphy (TPBS) to diagnose infection were studied. Patients with an acute infection or inadequate culture sampling were excluded. SII was diagnosed if ≥ 2 of the same microorganism(s) were isolated from intra-operative tissue cultures.

RESULTS

30 patients were included. The indication for revision surgery was pseudoarthrosis in the majority of patients (n = 15). 22 patients (73%) were diagnosed with SII. In all infected cases, Cutibacterium acnes was isolated, including 5 cases with a polymicrobial infection. The majority of patients had low inflammatory parameters preoperatively. For CRP > 10.0 mg/L, the sensitivity was 9.1% and specificity 100%; for ESR > 30 mm/h, the sensitivity was 9.1% and specificity 100%. The diagnostic accuracy for nuclear imaging was 64% for the FDG-PET/CT and 67% for the TPBS to diagnose infection.

CONCLUSIONS

The prevalence of SII in patients undergoing revision spinal surgery is high, with Cutibacterium acnes as the main pathogen. No diagnostic tests could be identified that could accurately diagnose or exclude SII prior to surgery. Future studies should aim to find more sensitive diagnostic modalities to detect low-grade inflammation.

Probing Beyond the Pain Scale: A Rare Case of Cutibacterium Acnes Septic Arthritis

Patients with sickle cell disease frequently present to the hospital for pain control secondary to vaso-occlusive crises (VOCs). Diagnostic challenges exist for healthcare providers in distinguishing joint pain secondary to a VOC from an intraarticular infection at initial presentation due to the lack of established clinical markers exclusive to one or the other. We present a 35-year-old female with sickle cell disease and avascular necrosis of bilateral hips and the right shoulder with several previous admissions for VOC pain control complaining of a "different" kind of pain in her shoulder. Treated initially for pain control, our patient was found to be suffering from culture-positive septic arthritis of the shoulder with Cutibacterium acnes, a rare source of de novo intraarticular infection. This case highlights the importance of incorporating patients' subjective descriptions of illness into differential diagnosis considerations, notably for those caring for patients with sickle cell disease. This case also establishes C. acnes as a rare organism responsible for de novo septic arthritis in the setting of sickle cell disease.

Comparison of two different antiseptics regarding intracutaneous microbial load after preoperative skin cleansing in total knee and hip arthroplasties

Periprosthetic infections (PPIs) are a serious concern in total knee and hip arthroplasty, and they have an increasing incidence. To prevent PPI, preoperative skin disinfection, as a key element of antisepsis, represents an important part of infection prevention. However, no specific antiseptic agent is endorsed by the relevant guidelines. The purpose of this retrospective, not randomized study was to investigate the difference in the residual bacteria load between an approved antiseptic with an alcohol-based solution with additional benzalkonium chloride (BAC) and an alcohol-based solution with additional octenidine dihydrochloride (OCT) at two different time periods. In 200 consecutive patients with total knee or hip arthroplasty, skin samples from the surgical sites were collected after skin disinfection with BAC (100 g solution contain: propan-2-ol 63.0 g, benzalkonium chloride 0.025 g) or OCT (100 g solution contain: octenidine dihydrochloride 0.1 g, propan-1-ol, 30.0 g, propan-2-ol 45.0 g) (100 patients per group). Following the separation of cutis and subcutis and its processing, culture was performed on different agar plates in aerobic and anaerobic environments. In the case of bacteria detection, the microbial identification was determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and the number of contaminated samples was compared between the groups. Additionally, multiple regression analysis was performed to examine the effect of the type of disinfectant, BMI, age, sex, rheumatoid arthritis, diabetes mellitus, skin disorders, smoking status, and localization of skin samples on positive bacteria detection. A total of 34 samples were positive for bacteria in the BAC group, while only 17 samples were positive in the OCT group (p = 0.005). Disinfectant type was the only significant parameter in the multiple regression analysis (p = 0.006). A significantly higher contamination rate of the subcutis was shown in the BAC group compared to the OCT group (19 vs. 9, p = 0,003). After the change from BAC to OCT in preoperative skin cleansing in the hip and knee areas, the number of positive cultures decreased by 50%, which might have been caused by a higher microbicidal activity of OCT. Therefore, the use of OCT in preoperative cleansing may reduce the risk of PPI in hip and knee surgery. Randomized controlled trials are required to confirm the effect and to evaluate if it reduces the risk of PPI.

Utility of disc space aspirate cell counts and differentials in the diagnosis of native vertebral osteomyelitis

Background: Aspiration of intervertebral disc space is often done to confirm the diagnosis of native vertebral osteomyelitis. A study has not been done examining the utility of cell counts and differentials of the aspirated fluid in diagnosing native vertebral osteomyelitis (NVO). Methods: In this feasibility study, we prospectively enrolled patients with a suspected diagnosis of NVO referred to the Division of Neuroradiology for image-guided needle aspiration of the intervertebral disc. In this study, manual cell count was done on the aspirated fluid, followed by a differential cytospin technique and touch prep. We obtained demographic, lab, and microbiologic data and used the receiver operating curve (ROC) for statistical analysis. Results: Over 12 months, we performed 17 aspirates on 14 patients. The median age was 70.5 years (range: 45-77). The median manual cell count on the aspirated fluid was 52 cells  µ L - 1 (range: 0-6656), the median neutrophil percentage on the touch prep slide was 73 % (range: 5 %-100 %), and the median neutrophil percentage on the cytospin slide was 82 % (range: 0 %-100 %). Routine bacterial cultures were positive in five cases, and the 16S ribosomal RNA gene polymerase chain reaction was positive in two cases. The optimal cutoff for a cell count of 104 total nucleated cells offered a sensitivity and specificity of 86 %, and a neutrophil cutoff of 83 % was associated with a 71 % sensitivity and specificity. Conclusion: An image-guided aspirated specimen leukocyte differential of ≥ 83  % neutrophils or a leukocyte count of ≥ 104   µ L - 1 was a sensitive and specific test for diagnosing patients with suspected NVO. Additionally, more extensive studies are warranted to confirm the findings.

Acne Vulgaris, Atopic Dermatitis and Rosacea: The Role of the Skin Microbiota-A Review

The skin harbors a huge number of different microorganisms such as bacteria, fungi and viruses, and it acts as a protective shield to prevent the invasion of pathogens and to maintain the health of the commensal microbiota. Several studies, in fact, have shown the importance of the skin microbiota for healthy skin. However, this balance can be altered by intrinsic and extrinsic factors, leading to the development of skin disease, such as acne vulgaris (AV), atopic dermatitis (AD) and rosacea(RS). Although these diseases are widespread and affect both adolescents and adults, the scientific correlation between these disorders and the skin microbiota and physiological parameters (TEWL, hydration and lipid composition) is still unclear. This review aims to investigate the current literature regarding the correlation between the skin microbiota and its imbalance underlying microbiological aspects, how the skin microbiota changes over the course of the disease and the current possible treatments. The following reported studies show a general imbalance of the bacterial flora. For this reason, more in-depth studies are necessary to explore the different subspecies and strains involved in all three diseases.

An evidence-based approach to managing unexpected positive cultures in shoulder arthroplasty

BACKGROUND

Unexpected positive cultures (UPCs) are very commonly found during shoulder arthroplasty when surgeons send intraoperative cultures to rule out periprosthetic joint infection (PJI) without clinical or radiographic signs of infection. Cutibacterium acnes is thought to be the most common bacteria cultured in this setting; however, the implications of an unexpected positive result are neither well defined nor agreed upon within the literature. The current review evaluates the incidence of UPCs and C acnes in reverse total arthroplasty; the clinical significance, if any, of these cultures; and various prognostic factors that may affect UPC incidence or recovery following PJI.

METHODS

A systematic review was performed with PRISMA guidelines using PubMed, CINAHL, and Scopus databases. Inclusion criteria included studies published from January 1, 2000, to May 20, 2021, that specifically reported on UPCs, native or revision shoulder surgery, and any study that directly addressed one of our 6 proposed clinical questions. Two independent investigators initially screened 267 articles for further evaluation. Data on study design, UPC rate/speciation, UPC risk factors, and UPC outcomes were analyzed and described.

RESULTS

A total of 22 studies met the inclusion criteria for this study. There was a pooled rate of 27.5% (653/2373) deep UPC specimen positivity, and C acnes represented 76.4% (499/653) of these positive specimens. Inanimate specimen positivity was reported at a pooled rate of 20.1% (29/144) across 3 studies. Male patients were more likely to have a UPC; however, the significance of prior surgery, surgical approach, and type of surgery conflicted across multiple articles. Patient-reported outcomes and reoperation rates did not differ between positive-UPC and negative-UPC patients. The utilization of antibiotics and treatment regimen varied across studies; however, the reinfection rates following surgery did not statistically differ based on the inclusion of antibiotics.

CONCLUSION

UPCs are a frequent finding during shoulder surgery and C acnes represents the highest percentage of cultured bacteria. Various preoperative risk factors, surgical techniques, and postoperative treatment regimens did not significantly affect the incidence of UPCs as well as the clinical outcomes for UPC vs. non-UPC patients. A standardized protocol for treatment and follow-up would decrease physician uncertainty when faced with a UPC from shoulder surgery. Given the results of this review, shoulder surgeons can consider not drastically altering the postoperative clinical course in the setting of UPC with no other evidence of PJI.

What do positive and negative Cutibacterium culture results in periprosthetic shoulder infection mean? A multi-institutional control study

BACKGROUND

Deep tissue culture specimens obtained at the time of revision shoulder arthroplasty are commonly positive for Cutibacterium. Clinical interpretation of positive cultures can be difficult. This was a multi-institutional study evaluating the accuracy of cultures for Cutibacterium using positive control (PC) and negative control (NC) samples. The relationship between time to culture positivity and strength of culture positivity was also studied.

METHODS

Eleven different institutions were each sent 12 blinded samples (10 PC and 2 NC samples). The 10 PC samples included 2 sets of 5 different dilutions of a Cutibacterium isolate from a failed total shoulder arthroplasty with a probable periprosthetic infection. At each institution, the samples were handled as if they were received from the operating room. Specimen growth, time to culture positivity, and strength of culture positivity (based on semiquantitative assessment) were reported.

RESULTS

A total of 110 PC samples and 22 NC samples were tested. One hundred percent of specimens at the 4 highest dilutions were positive for Cutibacterium. At the lowest dilution, 91% of samples showed positive findings. Cutibacterium grew in 14% of NC samples. Cutibacterium grew in PC samples at an average of 4.0 ± 1.3 days, and all of these samples showed growth within 7 days. The time to positivity was significantly shorter (P < .001) and the strength of positivity was significantly higher (P < .001) in true-positive cultures compared with false-positive cultures.

CONCLUSIONS

This multi-institutional study suggests that different institutions may report highly consistent rates of culture positivity for revision shoulder arthroplasty samples with higher bacterial loads. In contrast, with lower bacterial loads, the results are somewhat less consistent. Clinicians should consider using a shorter time to positivity and a higher strength of positivity as adjuncts in determining whether a tissue culture sample is a true positive.

Editorial Commentary: Dermal Allografts Are Indicated for Repair of Irreparable Rotator Cuff Tears and for Revision Surgery, and May Be Cost-Effective for Primary Repair

Improving rotator cuff repair results is the goal of all shoulder surgeons. The addition of a biologic graft may speed healing, allow accelerated rehabilitation, and increase healing rates. Recent research suggests that augmentation of rotator cuff repair using dermal allograft may be cost-effective. Indications for dermal allografts are revision rotator cuff repairs and primary cuff repairs in which a tensionless repair cannot be accomplished. Allografts act as a load-sharing device to allow tendons to heal without tension. They also serve to fill the gap in irreparable cuff tears. It is important to understand that augmentation will not compensate for advanced muscle fatty atrophy or neurapraxia. Precautions to prevent Cutibacterium acne nosocomial infection are essential. The healing time or dermal grafts is considerably longer than the repaired native cuff tendon, requiring supervised rehabilitation. Dermal allografts are a crucial tool for repair of irreparable rotator cuff tears and for revision surgery. From an economic standpoint, they now also may be considered for use in primary rotator cuff repair surgery.

The efficacy of topical preparations in reducing the incidence of Cutibacterium acnes at the start and conclusion of total shoulder arthroplasty: a randomized controlled trial

BACKGROUND

Preoperative skin preparations for total shoulder arthroplasty (TSA) are not standardized for Cutibacterium acnes eradication. Topical benzyl peroxide (BPO) and benzyl peroxide with clindamycin (BPO-C) have been shown to reduce the bacterial load of C acnes on the skin. Our aim was to investigate whether preoperative application of these topical antimicrobials reduced superficial colonization and deep tissue inoculation of C acnes in patients undergoing TSA.

METHODS

In a prospective, single-blinded randomized controlled trial, 101 patients undergoing primary TSA were randomized to receive either topical pHisoHex (hexachlorophene [1% triclosan; sodium benzoate, 5 mg/mL; and benzyl alcohol, 5 mg/mL]) (n = 35), 5% BPO (n = 33), or 5% BPO with 1% clindamycin (n = 33). Skin swabs obtained prior to topical application and after topical application before surgery, as well as 3 intraoperative swabs (dermis after incision, on joint capsule entry, and dermis at wound closure), were cultured. The primary outcome was positive culture findings and successful decolonization.

RESULTS

All 3 topical preparations were effective in decreasing the rate of C acnes. The application of pHisoHex reduced skin colonization by 50%, BPO reduced skin colonization by 73.7%, and BPO-C reduced skin colonization by 81.5%. The topical preparation of BPO-C was more effective in decreasing the rate of C acnes at the preoperative and intraoperative swab time points compared with pHisoHex and BPO (P = .003). Failure to eradicate C acnes with topical preparations consistently resulted in deep tissue inoculation. There was an increase in the C acnes contamination rate on the skin during closure (33%) compared with skin cultures taken at surgery commencement (22%).

CONCLUSION

Topical application of BPO and BPO-C preoperatively is more effective than pHisoHex in reducing colonization and contamination of the surgical field with C acnes in patients undergoing TSA.

Efficacy of Three Povidone Iodine Formulations against Cutibacterium acnes Assessed through In Vitro Studies: A Preliminary Study

Cutibacterium acnes (C. acnes, formerly known as Propionibacterium acnes) is the major causative agent of prosthetic joint infections (PJI). Treatment of PJI with antibiotics is difficult due to antibiotic resistance and adverse side effects on patients’ health. Proper disinfection of the surgical site using a variety of povidone iodine formulations could prevent C. acnes infection. In the current study, the efficacy of the three povidone iodine (PVP-I) formulations, viz: PVP-I 10% dermic solution, PVP-I 5% alcoholic solution and PVP-I 4% scrub, was tested against C. acnes, in vitro, in the presence of interfering substances mimicking soiling conditions. C. acnes strain ATCC 6919 was used to test the bactericidal activity of the povidone iodine formulations according to the modified dilution-neutralization method described in French Norm EN standard 13727. A 3-log reduction in the bacterial cell count in 60 s was considered to be significant. The results showed that under experimental conditions, the three PVP-I formulations displayed bactericidal activity against the micro-organism, Cutibacterium acnes, and that the lowest concentration of povidone-iodine active against C. acnes was 0.4%. These results are encouraging as PVP-I offers a low-cost and efficient method of disinfection.

Occult clavicle osteomyelitis caused by Cutibacterium acnes (C. acnes) after coracoclavicular ligament reconstruction: A case report and review of the literature

INTRODUCTION

Clavicle osteomyelitis is a rare, but serious complication following operative repair of acromioclavicular (AC) joint separations. Cutibacterium Acnes (C. acnes) is rarely a causative pathogen in clavicle osteomyelitis and diagnosis can be challenging due to the indolent nature of this organism.

CASE PRESENTATION

A 45-50 year old female with a chronic AC joint separation underwent an open coracoclavicular reconstruction using semitendinosus allograft and FiberTape (Arthrex, Naples, FL). At the six month follow up, the patient complained of mild persistent pain. Imaging demonstrated widening of the medial suture tunnel with distal clavicle osteolysis, which was concerning for osteomyelitis. This was successfully treated with implant removal revision surgery and additional intravenous antibiotics. Cultures of the graft material were positive for C. acnes. The patient continued to have osteolysis of the distal left clavicle for a period of time despite resolution of osteomyelitis.

DISCUSSION

C. acnes osteomyelitis of the clavicle is difficult to diagnose because of its vague associated symptoms when implicated in infections. There are no known obvious predisposing factors for C. acnes clavicle osteomyelitis. Literature suggests management should include aggressive irrigation and debridement, removal of any hardware, and extended intravenous antibiotic administration.

CONCLUSION

C. acnes clavicular osteomyelitis is uncommon, thus established treatment guidelines have not yet been formed. Revision surgery to remove graft material, irrigate, and debride in addition to antibiotic treatment was successful for our patient. Additional pathologic manifestations of C. acnes infections could include continued clavicular erosion post-clearance of infection, although further investigation is necessary.

Amplicon-Based Next-Generation Sequencing as a Diagnostic Tool for the Detection of Phylotypes of Cutibacterium acnes in Orthopedic Implant-Associated Infections

The diagnosis of orthopedic implant-associated infections (OIAIs) caused by the slow-growing anaerobic bacterium Cutibacterium acnes is challenging. The mild clinical presentations of this low-virulent bacterium along with its ubiquitous presence on human skin and human-dominated environments often make it difficult to differentiate true infection from contamination. Previous studies have applied C. acnes phylotyping as a potential avenue to distinguish contamination from infection; several studies reported a prevalence of phylotypes IB [corresponding to type H in the single-locus sequence typing (SLST) scheme] and II (SLST type K) in OIAIs, while a few others found phylotype IA1 (more specifically SLST type A) to be abundant. However, phylotype determination has mainly been done in a culture-dependent manner on randomly selected C. acnes isolates. Here, we used a culture-independent amplicon-based next-generation sequencing (aNGS) approach to determine the presence and relative abundances of C. acnes phylotypes in clinical OIAI specimens. As amplicon, the SLST target was used, a genomic fragment that is present in all C. acnes strains known to date. The aNGS approach was applied to 30 sonication fluid (SF) samples obtained from implants removed during revision surgeries, including 17 C. acnes culture-positive and 13 culture-negative SF specimens. In 53% of the culture-positive samples, SLST types were identified: relative abundances were highest for K-type C. acnes, followed by H- and D-type C. acnes. Other types, including A- and C-type C. acnes that are more prevalent on human skin, had low relative abundances. The aNGS results were compared with, and confirmed by a culture-dependent approach, which included the isolation, whole genome sequencing (WGS) and phylotyping of 36 strains of C. acnes obtained from these SF samples. Besides serving as a powerful adjunct to identify C. acnes phylotypes, the aNGS approach could also distinguish mono- from heterotypic infections, i.e., infections caused by more than one phylotype of C. acnes: in eight out of nine culture-positive SF samples multiple C. acnes types were detected. We propose that the aNGS approach, along with the patient's clinical information, tissue and SF cultures and WGS, could help differentiate C. acnes contamination from true infection.

Pain at the Cochlear Implant Site Requiring Device Removal in Pediatric Patients

OBJECTIVES

Idiopathic pain at the cochlear implant (CI) site outside of the immediate postoperative period is an uncommon occurrence but may necessitate device explantation. Our objective was to describe the clinical course for pediatric patients with CI site pain who ultimately required device explantation.

STUDY DESIGN

Retrospective chart review.

METHODS

We performed a retrospective database review of CIs performed at a tertiary referral center for pediatric cochlear implantation. We specifically evaluated pediatric patients who presented with pain at or near the CI device site and ultimately required explantation.

RESULTS

Fifteen patients (16 CIs) had pain at or near the CI site requiring device explantation. Cultures taken during site exploration or device explantation identified bacteria in 86% and 81% of procedures, respectively. Propionibacterium acnes and Staphylococcus non-aureus were the most commonly identified organisms.

CONCLUSIONS

The majority of patients with idiopathic pain in this cohort ultimately requiring CI explantation had chronic bacterial colonization.

LEVEL OF EVIDENCE

Level 4 (Case series) Laryngoscope, 2022.

Temporal Variation of the Facial Skin Microbiome: A 2-Year Longitudinal Study in Healthy Adults

BACKGROUND

The human skin microbiome is highly personalized, depending on, for example, body site, age, gender, and lifestyle factors. The temporal stability of an individual's skin microbiome-its resiliency and robustness over months and years-is also a personalized feature of the microbiome. The authors measured the temporal stability of the facial skin microbiome in a large cohort of subjects. In addition to measuring microbiome dynamics, they tracked facial skin condition using noninvasive, objective imaging and biophysical measures to identify significant facial features associated with temporal changes in microbiome diversity and composition.

METHODS

The authors used 16S ribosomal RNA amplicon sequencing to track cheek and forehead skin microbiome diversity and composition annually over a 2-year period (2017-2019) in 115 healthy adult men and women. Skin metadata included facial features, such as wrinkles, hyperpigmentation, porphyrins, and skin color tone, as well as biophysical parameters for stratum corneum barrier function, pH, hydration, and elasticity.

RESULTS

Across the subject population, the facial skin microbiome composition and diversity were relatively stable, showing minor variation over the 2-year period. However, for some subjects, composition, diversity, and relative abundance of specific organisms showed substantial changes from one year to the next, and these changes were associated with changes in stratum corneum barrier function and follicular porphyrins.

CONCLUSIONS

For healthy people, facial skin microbiome diversity and composition are relatively stable from year to year. Tracking the temporal changes in the microbiome along with skin phenotypic changes allows for a deeper understanding of the skin microbiome's role in health and disease. These results should be helpful in the design of longer-term intervention trials with microbiome-based skin care treatments.

Editorial Commentary: Hydrogen Peroxide in the Perioperative Skin Preparation is a No Brainer for Shoulder Surgery (Despite Imperfect Data)

Although the clinical impact of positive cultures at the time of primary shoulder surgery remain unknown, much effort has been placed on identifying agents for skin preparation that reduce Cutibacterium acnes skin colonization. Although several randomized controlled trials of hydrogen peroxide use as part of the skin preparation exist, they are plagued by small sample sizes that lead to inadequate power or statistical fragility. Despite the lack of perfect data, our clinical experience and break-even analyses indicate value to routine use of hydrogen peroxide as part of the perioperative skin preparation prior to shoulder surgery.